// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2017-2020, The Linux Foundation. All rights reserved.
 * Copyright (c) 2020, Linaro Limited
 */

#include <dt-bindings/dma/qcom-gpi.h>
#include <linux/bitfield.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/module.h>
#include <linux/of_dma.h>
#include <linux/platform_device.h>
#include <linux/dma/qcom-gpi-dma.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include "../dmaengine.h"
#include "../virt-dma.h"

#define TRE_TYPE_DMA            0x10
#define TRE_TYPE_IMMEDIATE_DMA  0x11
#define TRE_TYPE_GO             0x20
#define TRE_TYPE_CONFIG0        0x22

/* TRE flags */
#define TRE_FLAGS_CHAIN         BIT(0)
#define TRE_FLAGS_IEOB          BIT(8)
#define TRE_FLAGS_IEOT          BIT(9)
#define TRE_FLAGS_BEI           BIT(10)
#define TRE_FLAGS_LINK          BIT(11)
#define TRE_FLAGS_TYPE          GENMASK(23, 16)

/* SPI CONFIG0 WD0 */
#define TRE_SPI_C0_WORD_SZ      GENMASK(4, 0)
#define TRE_SPI_C0_LOOPBACK     BIT(8)
#define TRE_SPI_C0_CS           BIT(11)
#define TRE_SPI_C0_CPHA         BIT(12)
#define TRE_SPI_C0_CPOL         BIT(13)
#define TRE_SPI_C0_TX_PACK      BIT(24)
#define TRE_SPI_C0_RX_PACK      BIT(25)

/* CONFIG0 WD2 */
#define TRE_C0_CLK_DIV          GENMASK(11, 0)
#define TRE_C0_CLK_SRC          GENMASK(19, 16)

/* SPI GO WD0 */
#define TRE_SPI_GO_CMD          GENMASK(4, 0)
#define TRE_SPI_GO_CS           GENMASK(10, 8)
#define TRE_SPI_GO_FRAG         BIT(26)

/* GO WD2 */
#define TRE_RX_LEN              GENMASK(23, 0)

/* I2C Config0 WD0 */
#define TRE_I2C_C0_TLOW         GENMASK(7, 0)
#define TRE_I2C_C0_THIGH        GENMASK(15, 8)
#define TRE_I2C_C0_TCYL         GENMASK(23, 16)
#define TRE_I2C_C0_TX_PACK      BIT(24)
#define TRE_I2C_C0_RX_PACK      BIT(25)

/* I2C GO WD0 */
#define TRE_I2C_GO_CMD          GENMASK(4, 0)
#define TRE_I2C_GO_ADDR         GENMASK(14, 8)
#define TRE_I2C_GO_STRETCH      BIT(26)

/* DMA TRE */
#define TRE_DMA_LEN             GENMASK(23, 0)
#define TRE_DMA_IMMEDIATE_LEN   GENMASK(3, 0)

/* Register offsets from gpi-top */
#define GPII_n_CH_k_CNTXT_0_OFFS(n, k)  (0x20000 + (0x4000 * (n)) + (0x80 * (k)))
#define GPII_n_CH_k_CNTXT_0_EL_SIZE     GENMASK(31, 24)
#define GPII_n_CH_k_CNTXT_0_CHSTATE     GENMASK(23, 20)
#define GPII_n_CH_k_CNTXT_0_ERIDX       GENMASK(18, 14)
#define GPII_n_CH_k_CNTXT_0_DIR         BIT(3)
#define GPII_n_CH_k_CNTXT_0_PROTO       GENMASK(2, 0)

#define GPII_n_CH_k_CNTXT_0(el_size, erindex, dir, chtype_proto)  \
        (FIELD_PREP(GPII_n_CH_k_CNTXT_0_EL_SIZE, el_size)       | \
         FIELD_PREP(GPII_n_CH_k_CNTXT_0_ERIDX, erindex)         | \
         FIELD_PREP(GPII_n_CH_k_CNTXT_0_DIR, dir)               | \
         FIELD_PREP(GPII_n_CH_k_CNTXT_0_PROTO, chtype_proto))

#define GPI_CHTYPE_DIR_IN       (0)
#define GPI_CHTYPE_DIR_OUT      (1)

#define GPI_CHTYPE_PROTO_GPI    (0x2)

#define GPII_n_CH_k_DOORBELL_0_OFFS(n, k)       (0x22000 + (0x4000 * (n)) + (0x8 * (k)))
#define GPII_n_CH_CMD_OFFS(n)                   (0x23008 + (0x4000 * (n)))
#define GPII_n_CH_CMD_OPCODE                    GENMASK(31, 24)
#define GPII_n_CH_CMD_CHID                      GENMASK(7, 0)
#define GPII_n_CH_CMD(opcode, chid)                              \
                     (FIELD_PREP(GPII_n_CH_CMD_OPCODE, opcode) | \
                      FIELD_PREP(GPII_n_CH_CMD_CHID, chid))

#define GPII_n_CH_CMD_ALLOCATE          (0)
#define GPII_n_CH_CMD_START             (1)
#define GPII_n_CH_CMD_STOP              (2)
#define GPII_n_CH_CMD_RESET             (9)
#define GPII_n_CH_CMD_DE_ALLOC          (10)
#define GPII_n_CH_CMD_UART_SW_STALE     (32)
#define GPII_n_CH_CMD_UART_RFR_READY    (33)
#define GPII_n_CH_CMD_UART_RFR_NOT_READY (34)

/* EV Context Array */
#define GPII_n_EV_CH_k_CNTXT_0_OFFS(n, k) (0x21000 + (0x4000 * (n)) + (0x80 * (k)))
#define GPII_n_EV_k_CNTXT_0_EL_SIZE     GENMASK(31, 24)
#define GPII_n_EV_k_CNTXT_0_CHSTATE     GENMASK(23, 20)
#define GPII_n_EV_k_CNTXT_0_INTYPE      BIT(16)
#define GPII_n_EV_k_CNTXT_0_CHTYPE      GENMASK(3, 0)

#define GPII_n_EV_k_CNTXT_0(el_size, inttype, chtype)           \
        (FIELD_PREP(GPII_n_EV_k_CNTXT_0_EL_SIZE, el_size) |     \
         FIELD_PREP(GPII_n_EV_k_CNTXT_0_INTYPE, inttype)  |     \
         FIELD_PREP(GPII_n_EV_k_CNTXT_0_CHTYPE, chtype))

#define GPI_INTTYPE_IRQ         (1)
#define GPI_CHTYPE_GPI_EV       (0x2)

enum CNTXT_OFFS {
        CNTXT_0_CONFIG = 0x0,
        CNTXT_1_R_LENGTH = 0x4,
        CNTXT_2_RING_BASE_LSB = 0x8,
        CNTXT_3_RING_BASE_MSB = 0xC,
        CNTXT_4_RING_RP_LSB = 0x10,
        CNTXT_5_RING_RP_MSB = 0x14,
        CNTXT_6_RING_WP_LSB = 0x18,
        CNTXT_7_RING_WP_MSB = 0x1C,
        CNTXT_8_RING_INT_MOD = 0x20,
        CNTXT_9_RING_INTVEC = 0x24,
        CNTXT_10_RING_MSI_LSB = 0x28,
        CNTXT_11_RING_MSI_MSB = 0x2C,
        CNTXT_12_RING_RP_UPDATE_LSB = 0x30,
        CNTXT_13_RING_RP_UPDATE_MSB = 0x34,
};

#define GPII_n_EV_CH_k_DOORBELL_0_OFFS(n, k)    (0x22100 + (0x4000 * (n)) + (0x8 * (k)))
#define GPII_n_EV_CH_CMD_OFFS(n)                (0x23010 + (0x4000 * (n)))
#define GPII_n_EV_CMD_OPCODE                    GENMASK(31, 24)
#define GPII_n_EV_CMD_CHID                      GENMASK(7, 0)
#define GPII_n_EV_CMD(opcode, chid)                              \
                     (FIELD_PREP(GPII_n_EV_CMD_OPCODE, opcode) | \
                      FIELD_PREP(GPII_n_EV_CMD_CHID, chid))

#define GPII_n_EV_CH_CMD_ALLOCATE               (0x00)
#define GPII_n_EV_CH_CMD_RESET                  (0x09)
#define GPII_n_EV_CH_CMD_DE_ALLOC               (0x0A)

#define GPII_n_CNTXT_TYPE_IRQ_OFFS(n)           (0x23080 + (0x4000 * (n)))

/* mask type register */
#define GPII_n_CNTXT_TYPE_IRQ_MSK_OFFS(n)       (0x23088 + (0x4000 * (n)))
#define GPII_n_CNTXT_TYPE_IRQ_MSK_BMSK          GENMASK(6, 0)
#define GPII_n_CNTXT_TYPE_IRQ_MSK_GENERAL       BIT(6)
#define GPII_n_CNTXT_TYPE_IRQ_MSK_IEOB          BIT(3)
#define GPII_n_CNTXT_TYPE_IRQ_MSK_GLOB          BIT(2)
#define GPII_n_CNTXT_TYPE_IRQ_MSK_EV_CTRL       BIT(1)
#define GPII_n_CNTXT_TYPE_IRQ_MSK_CH_CTRL       BIT(0)

#define GPII_n_CNTXT_SRC_GPII_CH_IRQ_OFFS(n)    (0x23090 + (0x4000 * (n)))
#define GPII_n_CNTXT_SRC_EV_CH_IRQ_OFFS(n)      (0x23094 + (0x4000 * (n)))

/* Mask channel control interrupt register */
#define GPII_n_CNTXT_SRC_CH_IRQ_MSK_OFFS(n)     (0x23098 + (0x4000 * (n)))
#define GPII_n_CNTXT_SRC_CH_IRQ_MSK_BMSK        GENMASK(1, 0)

/* Mask event control interrupt register */
#define GPII_n_CNTXT_SRC_EV_CH_IRQ_MSK_OFFS(n)  (0x2309C + (0x4000 * (n)))
#define GPII_n_CNTXT_SRC_EV_CH_IRQ_MSK_BMSK     BIT(0)

#define GPII_n_CNTXT_SRC_CH_IRQ_CLR_OFFS(n)     (0x230A0 + (0x4000 * (n)))
#define GPII_n_CNTXT_SRC_EV_CH_IRQ_CLR_OFFS(n)  (0x230A4 + (0x4000 * (n)))

/* Mask event interrupt register */
#define GPII_n_CNTXT_SRC_IEOB_IRQ_MSK_OFFS(n)   (0x230B8 + (0x4000 * (n)))
#define GPII_n_CNTXT_SRC_IEOB_IRQ_MSK_BMSK      BIT(0)

#define GPII_n_CNTXT_SRC_IEOB_IRQ_CLR_OFFS(n)   (0x230C0 + (0x4000 * (n)))
#define GPII_n_CNTXT_GLOB_IRQ_STTS_OFFS(n)      (0x23100 + (0x4000 * (n)))
#define GPI_GLOB_IRQ_ERROR_INT_MSK              BIT(0)

/* GPII specific Global - Enable bit register */
#define GPII_n_CNTXT_GLOB_IRQ_EN_OFFS(n)        (0x23108 + (0x4000 * (n)))
#define GPII_n_CNTXT_GLOB_IRQ_CLR_OFFS(n)       (0x23110 + (0x4000 * (n)))
#define GPII_n_CNTXT_GPII_IRQ_STTS_OFFS(n)      (0x23118 + (0x4000 * (n)))

/* GPII general interrupt - Enable bit register */
#define GPII_n_CNTXT_GPII_IRQ_EN_OFFS(n)        (0x23120 + (0x4000 * (n)))
#define GPII_n_CNTXT_GPII_IRQ_EN_BMSK           GENMASK(3, 0)

#define GPII_n_CNTXT_GPII_IRQ_CLR_OFFS(n)       (0x23128 + (0x4000 * (n)))

/* GPII Interrupt Type register */
#define GPII_n_CNTXT_INTSET_OFFS(n)             (0x23180 + (0x4000 * (n)))
#define GPII_n_CNTXT_INTSET_BMSK                BIT(0)

#define GPII_n_CNTXT_MSI_BASE_LSB_OFFS(n)       (0x23188 + (0x4000 * (n)))
#define GPII_n_CNTXT_MSI_BASE_MSB_OFFS(n)       (0x2318C + (0x4000 * (n)))
#define GPII_n_CNTXT_SCRATCH_0_OFFS(n)          (0x23400 + (0x4000 * (n)))
#define GPII_n_CNTXT_SCRATCH_1_OFFS(n)          (0x23404 + (0x4000 * (n)))

#define GPII_n_ERROR_LOG_OFFS(n)                (0x23200 + (0x4000 * (n)))

/* QOS Registers */
#define GPII_n_CH_k_QOS_OFFS(n, k)              (0x2005C + (0x4000 * (n)) + (0x80 * (k)))

/* Scratch registers */
#define GPII_n_CH_k_SCRATCH_0_OFFS(n, k)        (0x20060 + (0x4000 * (n)) + (0x80 * (k)))
#define GPII_n_CH_k_SCRATCH_0_SEID              GENMASK(2, 0)
#define GPII_n_CH_k_SCRATCH_0_PROTO             GENMASK(7, 4)
#define GPII_n_CH_k_SCRATCH_0_PAIR              GENMASK(20, 16)
#define GPII_n_CH_k_SCRATCH_0(pair, proto, seid)                \
                             (FIELD_PREP(GPII_n_CH_k_SCRATCH_0_PAIR, pair)      | \
                              FIELD_PREP(GPII_n_CH_k_SCRATCH_0_PROTO, proto)    | \
                              FIELD_PREP(GPII_n_CH_k_SCRATCH_0_SEID, seid))
#define GPII_n_CH_k_SCRATCH_1_OFFS(n, k)        (0x20064 + (0x4000 * (n)) + (0x80 * (k)))
#define GPII_n_CH_k_SCRATCH_2_OFFS(n, k)        (0x20068 + (0x4000 * (n)) + (0x80 * (k)))
#define GPII_n_CH_k_SCRATCH_3_OFFS(n, k)        (0x2006C + (0x4000 * (n)) + (0x80 * (k)))

struct __packed gpi_tre {
        u32 dword[4];
};

enum msm_gpi_tce_code {
        MSM_GPI_TCE_SUCCESS = 1,
        MSM_GPI_TCE_EOT = 2,
        MSM_GPI_TCE_EOB = 4,
        MSM_GPI_TCE_UNEXP_ERR = 16,
};

#define CMD_TIMEOUT_MS          (250)

#define MAX_CHANNELS_PER_GPII   (2)
#define GPI_TX_CHAN             (0)
#define GPI_RX_CHAN             (1)
#define STATE_IGNORE            (U32_MAX)
#define EV_FACTOR               (2)
#define REQ_OF_DMA_ARGS         (5) /* # of arguments required from client */
#define CHAN_TRES               64

struct __packed xfer_compl_event {
        u64 ptr;
        u32 length:24;
        u8 code;
        u16 status;
        u8 type;
        u8 chid;
};

struct __packed immediate_data_event {
        u8 data_bytes[8];
        u8 length:4;
        u8 resvd:4;
        u16 tre_index;
        u8 code;
        u16 status;
        u8 type;
        u8 chid;
};

struct __packed qup_notif_event {
        u32 status;
        u32 time;
        u32 count:24;
        u8 resvd;
        u16 resvd1;
        u8 type;
        u8 chid;
};

struct __packed gpi_ere {
        u32 dword[4];
};

enum GPI_EV_TYPE {
        XFER_COMPLETE_EV_TYPE = 0x22,
        IMMEDIATE_DATA_EV_TYPE = 0x30,
        QUP_NOTIF_EV_TYPE = 0x31,
        STALE_EV_TYPE = 0xFF,
};

union __packed gpi_event {
        struct __packed xfer_compl_event xfer_compl_event;
        struct __packed immediate_data_event immediate_data_event;
        struct __packed qup_notif_event qup_notif_event;
        struct __packed gpi_ere gpi_ere;
};

enum gpii_irq_settings {
        DEFAULT_IRQ_SETTINGS,
        MASK_IEOB_SETTINGS,
};

enum gpi_ev_state {
        DEFAULT_EV_CH_STATE = 0,
        EV_STATE_NOT_ALLOCATED = DEFAULT_EV_CH_STATE,
        EV_STATE_ALLOCATED,
        MAX_EV_STATES
};

static const char *const gpi_ev_state_str[MAX_EV_STATES] = {
        [EV_STATE_NOT_ALLOCATED] = "NOT ALLOCATED",
        [EV_STATE_ALLOCATED] = "ALLOCATED",
};

#define TO_GPI_EV_STATE_STR(_state) (((_state) >= MAX_EV_STATES) ? \
                                    "INVALID" : gpi_ev_state_str[(_state)])

enum gpi_ch_state {
        DEFAULT_CH_STATE = 0x0,
        CH_STATE_NOT_ALLOCATED = DEFAULT_CH_STATE,
        CH_STATE_ALLOCATED = 0x1,
        CH_STATE_STARTED = 0x2,
        CH_STATE_STOPPED = 0x3,
        CH_STATE_STOP_IN_PROC = 0x4,
        CH_STATE_ERROR = 0xf,
        MAX_CH_STATES
};

enum gpi_cmd {
        GPI_CH_CMD_BEGIN,
        GPI_CH_CMD_ALLOCATE = GPI_CH_CMD_BEGIN,
        GPI_CH_CMD_START,
        GPI_CH_CMD_STOP,
        GPI_CH_CMD_RESET,
        GPI_CH_CMD_DE_ALLOC,
        GPI_CH_CMD_UART_SW_STALE,
        GPI_CH_CMD_UART_RFR_READY,
        GPI_CH_CMD_UART_RFR_NOT_READY,
        GPI_CH_CMD_END = GPI_CH_CMD_UART_RFR_NOT_READY,
        GPI_EV_CMD_BEGIN,
        GPI_EV_CMD_ALLOCATE = GPI_EV_CMD_BEGIN,
        GPI_EV_CMD_RESET,
        GPI_EV_CMD_DEALLOC,
        GPI_EV_CMD_END = GPI_EV_CMD_DEALLOC,
        GPI_MAX_CMD,
};

#define IS_CHAN_CMD(_cmd) ((_cmd) <= GPI_CH_CMD_END)

static const char *const gpi_cmd_str[GPI_MAX_CMD] = {
        [GPI_CH_CMD_ALLOCATE] = "CH ALLOCATE",
        [GPI_CH_CMD_START] = "CH START",
        [GPI_CH_CMD_STOP] = "CH STOP",
        [GPI_CH_CMD_RESET] = "CH_RESET",
        [GPI_CH_CMD_DE_ALLOC] = "DE ALLOC",
        [GPI_CH_CMD_UART_SW_STALE] = "UART SW STALE",
        [GPI_CH_CMD_UART_RFR_READY] = "UART RFR READY",
        [GPI_CH_CMD_UART_RFR_NOT_READY] = "UART RFR NOT READY",
        [GPI_EV_CMD_ALLOCATE] = "EV ALLOCATE",
        [GPI_EV_CMD_RESET] = "EV RESET",
        [GPI_EV_CMD_DEALLOC] = "EV DEALLOC",
};

#define TO_GPI_CMD_STR(_cmd) (((_cmd) >= GPI_MAX_CMD) ? "INVALID" : \
                                  gpi_cmd_str[(_cmd)])

/*
 * @DISABLE_STATE: no register access allowed
 * @CONFIG_STATE:  client has configured the channel
 * @PREP_HARDWARE: register access is allowed
 *                 however, no processing EVENTS
 * @ACTIVE_STATE: channels are fully operational
 * @PREPARE_TERMINATE: graceful termination of channels
 *                     register access is allowed
 * @PAUSE_STATE: channels are active, but not processing any events
 */
enum gpi_pm_state {
        DISABLE_STATE,
        CONFIG_STATE,
        PREPARE_HARDWARE,
        ACTIVE_STATE,
        PREPARE_TERMINATE,
        PAUSE_STATE,
        MAX_PM_STATE
};

#define REG_ACCESS_VALID(_pm_state) ((_pm_state) >= PREPARE_HARDWARE)

static const char *const gpi_pm_state_str[MAX_PM_STATE] = {
        [DISABLE_STATE] = "DISABLE",
        [CONFIG_STATE] = "CONFIG",
        [PREPARE_HARDWARE] = "PREPARE HARDWARE",
        [ACTIVE_STATE] = "ACTIVE",
        [PREPARE_TERMINATE] = "PREPARE TERMINATE",
        [PAUSE_STATE] = "PAUSE",
};

#define TO_GPI_PM_STR(_state) (((_state) >= MAX_PM_STATE) ? \
                              "INVALID" : gpi_pm_state_str[(_state)])

static const struct {
        enum gpi_cmd gpi_cmd;
        u32 opcode;
        u32 state;
} gpi_cmd_info[GPI_MAX_CMD] = {
        {
                GPI_CH_CMD_ALLOCATE,
                GPII_n_CH_CMD_ALLOCATE,
                CH_STATE_ALLOCATED,
        },
        {
                GPI_CH_CMD_START,
                GPII_n_CH_CMD_START,
                CH_STATE_STARTED,
        },
        {
                GPI_CH_CMD_STOP,
                GPII_n_CH_CMD_STOP,
                CH_STATE_STOPPED,
        },
        {
                GPI_CH_CMD_RESET,
                GPII_n_CH_CMD_RESET,
                CH_STATE_ALLOCATED,
        },
        {
                GPI_CH_CMD_DE_ALLOC,
                GPII_n_CH_CMD_DE_ALLOC,
                CH_STATE_NOT_ALLOCATED,
        },
        {
                GPI_CH_CMD_UART_SW_STALE,
                GPII_n_CH_CMD_UART_SW_STALE,
                STATE_IGNORE,
        },
        {
                GPI_CH_CMD_UART_RFR_READY,
                GPII_n_CH_CMD_UART_RFR_READY,
                STATE_IGNORE,
        },
        {
                GPI_CH_CMD_UART_RFR_NOT_READY,
                GPII_n_CH_CMD_UART_RFR_NOT_READY,
                STATE_IGNORE,
        },
        {
                GPI_EV_CMD_ALLOCATE,
                GPII_n_EV_CH_CMD_ALLOCATE,
                EV_STATE_ALLOCATED,
        },
        {
                GPI_EV_CMD_RESET,
                GPII_n_EV_CH_CMD_RESET,
                EV_STATE_ALLOCATED,
        },
        {
                GPI_EV_CMD_DEALLOC,
                GPII_n_EV_CH_CMD_DE_ALLOC,
                EV_STATE_NOT_ALLOCATED,
        },
};

struct gpi_ring {
        void *pre_aligned;
        size_t alloc_size;
        phys_addr_t phys_addr;
        dma_addr_t dma_handle;
        void *base;
        void *wp;
        void *rp;
        u32 len;
        u32 el_size;
        u32 elements;
        bool configured;
};

struct gpi_dev {
        struct dma_device dma_device;
        struct device *dev;
        struct resource *res;
        void __iomem *regs;
        void __iomem *ee_base; /*ee register base address*/
        u32 max_gpii; /* maximum # of gpii instances available per gpi block */
        u32 gpii_mask; /* gpii instances available for apps */
        u32 ev_factor; /* ev ring length factor */
        struct gpii *gpiis;
};

struct gchan {
        struct virt_dma_chan vc;
        u32 chid;
        u32 seid;
        u32 protocol;
        struct gpii *gpii;
        enum gpi_ch_state ch_state;
        enum gpi_pm_state pm_state;
        void __iomem *ch_cntxt_base_reg;
        void __iomem *ch_cntxt_db_reg;
        void __iomem *ch_cmd_reg;
        u32 dir;
        struct gpi_ring ch_ring;
        void *config;
};

struct gpii {
        u32 gpii_id;
        struct gchan gchan[MAX_CHANNELS_PER_GPII];
        struct gpi_dev *gpi_dev;
        int irq;
        void __iomem *regs; /* points to gpi top */
        void __iomem *ev_cntxt_base_reg;
        void __iomem *ev_cntxt_db_reg;
        void __iomem *ev_ring_rp_lsb_reg;
        void __iomem *ev_cmd_reg;
        void __iomem *ieob_clr_reg;
        struct mutex ctrl_lock;
        enum gpi_ev_state ev_state;
        bool configured_irq;
        enum gpi_pm_state pm_state;
        rwlock_t pm_lock;
        struct gpi_ring ev_ring;
        struct tasklet_struct ev_task; /* event processing tasklet */
        struct completion cmd_completion;
        enum gpi_cmd gpi_cmd;
        u32 cntxt_type_irq_msk;
        bool ieob_set;
};

#define MAX_TRE 3

struct gpi_desc {
        struct virt_dma_desc vd;
        size_t len;
        void *db; /* DB register to program */
        struct gchan *gchan;
        struct gpi_tre tre[MAX_TRE];
        u32 num_tre;
};

static const u32 GPII_CHAN_DIR[MAX_CHANNELS_PER_GPII] = {
        GPI_CHTYPE_DIR_OUT, GPI_CHTYPE_DIR_IN
};

static irqreturn_t gpi_handle_irq(int irq, void *data);
static void gpi_ring_recycle_ev_element(struct gpi_ring *ring);
static int gpi_ring_add_element(struct gpi_ring *ring, void **wp);
static void gpi_process_events(struct gpii *gpii);

static inline struct gchan *to_gchan(struct dma_chan *dma_chan)
{
        return container_of(dma_chan, struct gchan, vc.chan);
}

static inline struct gpi_desc *to_gpi_desc(struct virt_dma_desc *vd)
{
        return container_of(vd, struct gpi_desc, vd);
}

static inline phys_addr_t to_physical(const struct gpi_ring *const ring,
                                      void *addr)
{
        return ring->phys_addr + (addr - ring->base);
}

static inline void *to_virtual(const struct gpi_ring *const ring, phys_addr_t addr)
{
        return ring->base + (addr - ring->phys_addr);
}

static inline u32 gpi_read_reg(struct gpii *gpii, void __iomem *addr)
{
        return readl_relaxed(addr);
}

static inline void gpi_write_reg(struct gpii *gpii, void __iomem *addr, u32 val)
{
        writel_relaxed(val, addr);
}

static __always_inline void
gpi_update_reg(struct gpii *gpii, u32 offset, u32 mask, u32 val)
{
        void __iomem *addr = gpii->regs + offset;
        u32 tmp = gpi_read_reg(gpii, addr);

        tmp &= ~mask;
        tmp |= u32_encode_bits(val, mask);

        gpi_write_reg(gpii, addr, tmp);
}

static void gpi_disable_interrupts(struct gpii *gpii)
{
        gpi_update_reg(gpii, GPII_n_CNTXT_TYPE_IRQ_MSK_OFFS(gpii->gpii_id),
                       GPII_n_CNTXT_TYPE_IRQ_MSK_BMSK, 0);
        gpi_update_reg(gpii, GPII_n_CNTXT_SRC_IEOB_IRQ_MSK_OFFS(gpii->gpii_id),
                       GPII_n_CNTXT_SRC_IEOB_IRQ_MSK_BMSK, 0);
        gpi_update_reg(gpii, GPII_n_CNTXT_SRC_CH_IRQ_MSK_OFFS(gpii->gpii_id),
                       GPII_n_CNTXT_SRC_CH_IRQ_MSK_BMSK, 0);
        gpi_update_reg(gpii, GPII_n_CNTXT_SRC_EV_CH_IRQ_MSK_OFFS(gpii->gpii_id),
                       GPII_n_CNTXT_SRC_EV_CH_IRQ_MSK_BMSK, 0);
        gpi_update_reg(gpii, GPII_n_CNTXT_GLOB_IRQ_EN_OFFS(gpii->gpii_id),
                       GPII_n_CNTXT_GPII_IRQ_EN_BMSK, 0);
        gpi_update_reg(gpii, GPII_n_CNTXT_GPII_IRQ_EN_OFFS(gpii->gpii_id),
                       GPII_n_CNTXT_GPII_IRQ_EN_BMSK, 0);
        gpi_update_reg(gpii, GPII_n_CNTXT_INTSET_OFFS(gpii->gpii_id),
                       GPII_n_CNTXT_INTSET_BMSK, 0);

        gpii->cntxt_type_irq_msk = 0;
        devm_free_irq(gpii->gpi_dev->dev, gpii->irq, gpii);
        gpii->configured_irq = false;
}

/* configure and enable interrupts */
static int gpi_config_interrupts(struct gpii *gpii, enum gpii_irq_settings settings, bool mask)
{
        const u32 enable = (GPII_n_CNTXT_TYPE_IRQ_MSK_GENERAL |
                              GPII_n_CNTXT_TYPE_IRQ_MSK_IEOB |
                              GPII_n_CNTXT_TYPE_IRQ_MSK_GLOB |
                              GPII_n_CNTXT_TYPE_IRQ_MSK_EV_CTRL |
                              GPII_n_CNTXT_TYPE_IRQ_MSK_CH_CTRL);
        int ret;

        if (!gpii->configured_irq) {
                ret = devm_request_irq(gpii->gpi_dev->dev, gpii->irq,
                                       gpi_handle_irq, IRQF_TRIGGER_HIGH,
                                       "gpi-dma", gpii);
                if (ret < 0) {
                        dev_err(gpii->gpi_dev->dev, "error request irq:%d ret:%d\n",
                                gpii->irq, ret);
                        return ret;
                }
        }

        if (settings == MASK_IEOB_SETTINGS) {
                /*
                 * GPII only uses one EV ring per gpii so we can globally
                 * enable/disable IEOB interrupt
                 */
                if (mask)
                        gpii->cntxt_type_irq_msk |= GPII_n_CNTXT_TYPE_IRQ_MSK_IEOB;
                else
                        gpii->cntxt_type_irq_msk &= ~(GPII_n_CNTXT_TYPE_IRQ_MSK_IEOB);
                gpi_update_reg(gpii, GPII_n_CNTXT_TYPE_IRQ_MSK_OFFS(gpii->gpii_id),
                               GPII_n_CNTXT_TYPE_IRQ_MSK_BMSK, gpii->cntxt_type_irq_msk);
        } else {
                gpi_update_reg(gpii, GPII_n_CNTXT_TYPE_IRQ_MSK_OFFS(gpii->gpii_id),
                               GPII_n_CNTXT_TYPE_IRQ_MSK_BMSK, enable);
                gpi_update_reg(gpii, GPII_n_CNTXT_SRC_IEOB_IRQ_MSK_OFFS(gpii->gpii_id),
                               GPII_n_CNTXT_SRC_IEOB_IRQ_MSK_BMSK,
                               GPII_n_CNTXT_SRC_IEOB_IRQ_MSK_BMSK);
                gpi_update_reg(gpii, GPII_n_CNTXT_SRC_CH_IRQ_MSK_OFFS(gpii->gpii_id),
                               GPII_n_CNTXT_SRC_CH_IRQ_MSK_BMSK,
                               GPII_n_CNTXT_SRC_CH_IRQ_MSK_BMSK);
                gpi_update_reg(gpii, GPII_n_CNTXT_SRC_EV_CH_IRQ_MSK_OFFS(gpii->gpii_id),
                               GPII_n_CNTXT_SRC_EV_CH_IRQ_MSK_BMSK,
                               GPII_n_CNTXT_SRC_EV_CH_IRQ_MSK_BMSK);
                gpi_update_reg(gpii, GPII_n_CNTXT_GLOB_IRQ_EN_OFFS(gpii->gpii_id),
                               GPII_n_CNTXT_GPII_IRQ_EN_BMSK,
                               GPII_n_CNTXT_GPII_IRQ_EN_BMSK);
                gpi_update_reg(gpii, GPII_n_CNTXT_GPII_IRQ_EN_OFFS(gpii->gpii_id),
                               GPII_n_CNTXT_GPII_IRQ_EN_BMSK, GPII_n_CNTXT_GPII_IRQ_EN_BMSK);
                gpi_update_reg(gpii, GPII_n_CNTXT_MSI_BASE_LSB_OFFS(gpii->gpii_id), U32_MAX, 0);
                gpi_update_reg(gpii, GPII_n_CNTXT_MSI_BASE_MSB_OFFS(gpii->gpii_id), U32_MAX, 0);
                gpi_update_reg(gpii, GPII_n_CNTXT_SCRATCH_0_OFFS(gpii->gpii_id), U32_MAX, 0);
                gpi_update_reg(gpii, GPII_n_CNTXT_SCRATCH_1_OFFS(gpii->gpii_id), U32_MAX, 0);
                gpi_update_reg(gpii, GPII_n_CNTXT_INTSET_OFFS(gpii->gpii_id),
                               GPII_n_CNTXT_INTSET_BMSK, 1);
                gpi_update_reg(gpii, GPII_n_ERROR_LOG_OFFS(gpii->gpii_id), U32_MAX, 0);

                gpii->cntxt_type_irq_msk = enable;
        }

        gpii->configured_irq = true;
        return 0;
}

/* Sends gpii event or channel command */
static int gpi_send_cmd(struct gpii *gpii, struct gchan *gchan,
                        enum gpi_cmd gpi_cmd)
{
        u32 chid = MAX_CHANNELS_PER_GPII;
        unsigned long timeout;
        void __iomem *cmd_reg;
        u32 cmd;

        if (gpi_cmd >= GPI_MAX_CMD)
                return -EINVAL;
        if (IS_CHAN_CMD(gpi_cmd))
                chid = gchan->chid;

        dev_dbg(gpii->gpi_dev->dev,
                "sending cmd: %s:%u\n", TO_GPI_CMD_STR(gpi_cmd), chid);

        /* send opcode and wait for completion */
        reinit_completion(&gpii->cmd_completion);
        gpii->gpi_cmd = gpi_cmd;

        cmd_reg = IS_CHAN_CMD(gpi_cmd) ? gchan->ch_cmd_reg : gpii->ev_cmd_reg;
        cmd = IS_CHAN_CMD(gpi_cmd) ? GPII_n_CH_CMD(gpi_cmd_info[gpi_cmd].opcode, chid) :
                                     GPII_n_EV_CMD(gpi_cmd_info[gpi_cmd].opcode, 0);
        gpi_write_reg(gpii, cmd_reg, cmd);
        timeout = wait_for_completion_timeout(&gpii->cmd_completion,
                                              msecs_to_jiffies(CMD_TIMEOUT_MS));
        if (!timeout) {
                dev_err(gpii->gpi_dev->dev, "cmd: %s completion timeout:%u\n",
                        TO_GPI_CMD_STR(gpi_cmd), chid);
                return -EIO;
        }

        /* confirm new ch state is correct , if the cmd is a state change cmd */
        if (gpi_cmd_info[gpi_cmd].state == STATE_IGNORE)
                return 0;

        if (IS_CHAN_CMD(gpi_cmd) && gchan->ch_state == gpi_cmd_info[gpi_cmd].state)
                return 0;

        if (!IS_CHAN_CMD(gpi_cmd) && gpii->ev_state == gpi_cmd_info[gpi_cmd].state)
                return 0;

        return -EIO;
}

/* program transfer ring DB register */
static inline void gpi_write_ch_db(struct gchan *gchan,
                                   struct gpi_ring *ring, void *wp)
{
        struct gpii *gpii = gchan->gpii;
        phys_addr_t p_wp;

        p_wp = to_physical(ring, wp);
        gpi_write_reg(gpii, gchan->ch_cntxt_db_reg, p_wp);
}

/* program event ring DB register */
static inline void gpi_write_ev_db(struct gpii *gpii,
                                   struct gpi_ring *ring, void *wp)
{
        phys_addr_t p_wp;

        p_wp = ring->phys_addr + (wp - ring->base);
        gpi_write_reg(gpii, gpii->ev_cntxt_db_reg, p_wp);
}

/* process transfer completion interrupt */
static void gpi_process_ieob(struct gpii *gpii)
{
        gpi_write_reg(gpii, gpii->ieob_clr_reg, BIT(0));

        gpi_config_interrupts(gpii, MASK_IEOB_SETTINGS, 0);
        tasklet_hi_schedule(&gpii->ev_task);
}

/* process channel control interrupt */
static void gpi_process_ch_ctrl_irq(struct gpii *gpii)
{
        u32 gpii_id = gpii->gpii_id;
        u32 offset = GPII_n_CNTXT_SRC_GPII_CH_IRQ_OFFS(gpii_id);
        u32 ch_irq = gpi_read_reg(gpii, gpii->regs + offset);
        struct gchan *gchan;
        u32 chid, state;

        /* clear the status */
        offset = GPII_n_CNTXT_SRC_CH_IRQ_CLR_OFFS(gpii_id);
        gpi_write_reg(gpii, gpii->regs + offset, (u32)ch_irq);

        for (chid = 0; chid < MAX_CHANNELS_PER_GPII; chid++) {
                if (!(BIT(chid) & ch_irq))
                        continue;

                gchan = &gpii->gchan[chid];
                state = gpi_read_reg(gpii, gchan->ch_cntxt_base_reg +
                                     CNTXT_0_CONFIG);
                state = FIELD_GET(GPII_n_CH_k_CNTXT_0_CHSTATE, state);

                /*
                 * CH_CMD_DEALLOC cmd always successful. However cmd does
                 * not change hardware status. So overwriting software state
                 * to default state.
                 */
                if (gpii->gpi_cmd == GPI_CH_CMD_DE_ALLOC)
                        state = DEFAULT_CH_STATE;
                gchan->ch_state = state;

                /*
                 * Triggering complete all if ch_state is not a stop in process.
                 * Stop in process is a transition state and we will wait for
                 * stop interrupt before notifying.
                 */
                if (gchan->ch_state != CH_STATE_STOP_IN_PROC)
                        complete_all(&gpii->cmd_completion);
        }
}

/* processing gpi general error interrupts */
static void gpi_process_gen_err_irq(struct gpii *gpii)
{
        u32 gpii_id = gpii->gpii_id;
        u32 offset = GPII_n_CNTXT_GPII_IRQ_STTS_OFFS(gpii_id);
        u32 irq_stts = gpi_read_reg(gpii, gpii->regs + offset);

        /* clear the status */
        dev_dbg(gpii->gpi_dev->dev, "irq_stts:0x%x\n", irq_stts);

        /* Clear the register */
        offset = GPII_n_CNTXT_GPII_IRQ_CLR_OFFS(gpii_id);
        gpi_write_reg(gpii, gpii->regs + offset, irq_stts);
}

/* processing gpi level error interrupts */
static void gpi_process_glob_err_irq(struct gpii *gpii)
{
        u32 gpii_id = gpii->gpii_id;
        u32 offset = GPII_n_CNTXT_GLOB_IRQ_STTS_OFFS(gpii_id);
        u32 irq_stts = gpi_read_reg(gpii, gpii->regs + offset);

        offset = GPII_n_CNTXT_GLOB_IRQ_CLR_OFFS(gpii_id);
        gpi_write_reg(gpii, gpii->regs + offset, irq_stts);

        /* only error interrupt should be set */
        if (irq_stts & ~GPI_GLOB_IRQ_ERROR_INT_MSK) {
                dev_err(gpii->gpi_dev->dev, "invalid error status:0x%x\n", irq_stts);
                return;
        }

        offset = GPII_n_ERROR_LOG_OFFS(gpii_id);
        gpi_write_reg(gpii, gpii->regs + offset, 0);
}

/* gpii interrupt handler */
static irqreturn_t gpi_handle_irq(int irq, void *data)
{
        struct gpii *gpii = data;
        u32 gpii_id = gpii->gpii_id;
        u32 type, offset;
        unsigned long flags;

        read_lock_irqsave(&gpii->pm_lock, flags);

        /*
         * States are out of sync to receive interrupt
         * while software state is in DISABLE state, bailing out.
         */
        if (!REG_ACCESS_VALID(gpii->pm_state)) {
                dev_err(gpii->gpi_dev->dev, "receive interrupt while in %s state\n",
                        TO_GPI_PM_STR(gpii->pm_state));
                goto exit_irq;
        }

        offset = GPII_n_CNTXT_TYPE_IRQ_OFFS(gpii->gpii_id);
        type = gpi_read_reg(gpii, gpii->regs + offset);

        do {
                /* global gpii error */
                if (type & GPII_n_CNTXT_TYPE_IRQ_MSK_GLOB) {
                        gpi_process_glob_err_irq(gpii);
                        type &= ~(GPII_n_CNTXT_TYPE_IRQ_MSK_GLOB);
                }

                /* transfer complete interrupt */
                if (type & GPII_n_CNTXT_TYPE_IRQ_MSK_IEOB) {
                        gpi_process_ieob(gpii);
                        type &= ~GPII_n_CNTXT_TYPE_IRQ_MSK_IEOB;
                }

                /* event control irq */
                if (type & GPII_n_CNTXT_TYPE_IRQ_MSK_EV_CTRL) {
                        u32 ev_state;
                        u32 ev_ch_irq;

                        dev_dbg(gpii->gpi_dev->dev,
                                "processing EV CTRL interrupt\n");
                        offset = GPII_n_CNTXT_SRC_EV_CH_IRQ_OFFS(gpii_id);
                        ev_ch_irq = gpi_read_reg(gpii, gpii->regs + offset);

                        offset = GPII_n_CNTXT_SRC_EV_CH_IRQ_CLR_OFFS
                                (gpii_id);
                        gpi_write_reg(gpii, gpii->regs + offset, ev_ch_irq);
                        ev_state = gpi_read_reg(gpii, gpii->ev_cntxt_base_reg +
                                                CNTXT_0_CONFIG);
                        ev_state = FIELD_GET(GPII_n_EV_k_CNTXT_0_CHSTATE, ev_state);

                        /*
                         * CMD EV_CMD_DEALLOC is always successful. However
                         * cmd does not change hardware status. So overwriting
                         * software state to default state.
                         */
                        if (gpii->gpi_cmd == GPI_EV_CMD_DEALLOC)
                                ev_state = DEFAULT_EV_CH_STATE;

                        gpii->ev_state = ev_state;
                        dev_dbg(gpii->gpi_dev->dev, "setting EV state to %s\n",
                                TO_GPI_EV_STATE_STR(gpii->ev_state));
                        complete_all(&gpii->cmd_completion);
                        type &= ~(GPII_n_CNTXT_TYPE_IRQ_MSK_EV_CTRL);
                }

                /* channel control irq */
                if (type & GPII_n_CNTXT_TYPE_IRQ_MSK_CH_CTRL) {
                        dev_dbg(gpii->gpi_dev->dev, "process CH CTRL interrupts\n");
                        gpi_process_ch_ctrl_irq(gpii);
                        type &= ~(GPII_n_CNTXT_TYPE_IRQ_MSK_CH_CTRL);
                }

                if (type) {
                        dev_err(gpii->gpi_dev->dev, "Unhandled interrupt status:0x%x\n", type);
                        gpi_process_gen_err_irq(gpii);
                        goto exit_irq;
                }

                offset = GPII_n_CNTXT_TYPE_IRQ_OFFS(gpii->gpii_id);
                type = gpi_read_reg(gpii, gpii->regs + offset);
        } while (type);

exit_irq:
        read_unlock_irqrestore(&gpii->pm_lock, flags);

        return IRQ_HANDLED;
}

/* process DMA Immediate completion data events */
static void gpi_process_imed_data_event(struct gchan *gchan,
                                        struct immediate_data_event *imed_event)
{
        struct gpii *gpii = gchan->gpii;
        struct gpi_ring *ch_ring = &gchan->ch_ring;
        void *tre = ch_ring->base + (ch_ring->el_size * imed_event->tre_index);
        struct dmaengine_result result;
        struct gpi_desc *gpi_desc;
        struct virt_dma_desc *vd;
        unsigned long flags;
        u32 chid;

        /*
         * If channel not active don't process event
         */
        if (gchan->pm_state != ACTIVE_STATE) {
                dev_err(gpii->gpi_dev->dev, "skipping processing event because ch @ %s state\n",
                        TO_GPI_PM_STR(gchan->pm_state));
                return;
        }

        spin_lock_irqsave(&gchan->vc.lock, flags);
        vd = vchan_next_desc(&gchan->vc);
        if (!vd) {
                struct gpi_ere *gpi_ere;
                struct gpi_tre *gpi_tre;

                spin_unlock_irqrestore(&gchan->vc.lock, flags);
                dev_dbg(gpii->gpi_dev->dev, "event without a pending descriptor!\n");
                gpi_ere = (struct gpi_ere *)imed_event;
                dev_dbg(gpii->gpi_dev->dev,
                        "Event: %08x %08x %08x %08x\n",
                        gpi_ere->dword[0], gpi_ere->dword[1],
                        gpi_ere->dword[2], gpi_ere->dword[3]);
                gpi_tre = tre;
                dev_dbg(gpii->gpi_dev->dev,
                        "Pending TRE: %08x %08x %08x %08x\n",
                        gpi_tre->dword[0], gpi_tre->dword[1],
                        gpi_tre->dword[2], gpi_tre->dword[3]);
                return;
        }
        gpi_desc = to_gpi_desc(vd);
        spin_unlock_irqrestore(&gchan->vc.lock, flags);

        /*
         * RP pointed by Event is to last TRE processed,
         * we need to update ring rp to tre + 1
         */
        tre += ch_ring->el_size;
        if (tre >= (ch_ring->base + ch_ring->len))
                tre = ch_ring->base;
        ch_ring->rp = tre;

        /* make sure rp updates are immediately visible to all cores */
        smp_wmb();

        chid = imed_event->chid;
        if (imed_event->code == MSM_GPI_TCE_EOT && gpii->ieob_set) {
                if (chid == GPI_RX_CHAN)
                        goto gpi_free_desc;
                else
                        return;
        }

        if (imed_event->code == MSM_GPI_TCE_UNEXP_ERR)
                result.result = DMA_TRANS_ABORTED;
        else
                result.result = DMA_TRANS_NOERROR;
        result.residue = gpi_desc->len - imed_event->length;

        dma_cookie_complete(&vd->tx);
        dmaengine_desc_get_callback_invoke(&vd->tx, &result);

gpi_free_desc:
        spin_lock_irqsave(&gchan->vc.lock, flags);
        list_del(&vd->node);
        spin_unlock_irqrestore(&gchan->vc.lock, flags);
        kfree(gpi_desc);
        gpi_desc = NULL;
}

/* processing transfer completion events */
static void gpi_process_xfer_compl_event(struct gchan *gchan,
                                         struct xfer_compl_event *compl_event)
{
        struct gpii *gpii = gchan->gpii;
        struct gpi_ring *ch_ring = &gchan->ch_ring;
        void *ev_rp = to_virtual(ch_ring, compl_event->ptr);
        struct virt_dma_desc *vd;
        struct gpi_desc *gpi_desc;
        struct dmaengine_result result;
        unsigned long flags;
        u32 chid;

        /* only process events on active channel */
        if (unlikely(gchan->pm_state != ACTIVE_STATE)) {
                dev_err(gpii->gpi_dev->dev, "skipping processing event because ch @ %s state\n",
                        TO_GPI_PM_STR(gchan->pm_state));
                return;
        }

        spin_lock_irqsave(&gchan->vc.lock, flags);
        vd = vchan_next_desc(&gchan->vc);
        if (!vd) {
                struct gpi_ere *gpi_ere;

                spin_unlock_irqrestore(&gchan->vc.lock, flags);
                dev_err(gpii->gpi_dev->dev, "Event without a pending descriptor!\n");
                gpi_ere = (struct gpi_ere *)compl_event;
                dev_err(gpii->gpi_dev->dev,
                        "Event: %08x %08x %08x %08x\n",
                        gpi_ere->dword[0], gpi_ere->dword[1],
                        gpi_ere->dword[2], gpi_ere->dword[3]);
                return;
        }

        gpi_desc = to_gpi_desc(vd);
        spin_unlock_irqrestore(&gchan->vc.lock, flags);

        /*
         * RP pointed by Event is to last TRE processed,
         * we need to update ring rp to ev_rp + 1
         */
        ev_rp += ch_ring->el_size;
        if (ev_rp >= (ch_ring->base + ch_ring->len))
                ev_rp = ch_ring->base;
        ch_ring->rp = ev_rp;

        /* update must be visible to other cores */
        smp_wmb();

        chid = compl_event->chid;
        if (compl_event->code == MSM_GPI_TCE_EOT && gpii->ieob_set) {
                if (chid == GPI_RX_CHAN)
                        goto gpi_free_desc;
                else
                        return;
        }

        if (compl_event->code == MSM_GPI_TCE_UNEXP_ERR) {
                dev_err(gpii->gpi_dev->dev, "Error in Transaction\n");
                result.result = DMA_TRANS_ABORTED;
        } else {
                dev_dbg(gpii->gpi_dev->dev, "Transaction Success\n");
                result.result = DMA_TRANS_NOERROR;
        }
        result.residue = gpi_desc->len - compl_event->length;
        dev_dbg(gpii->gpi_dev->dev, "Residue %d\n", result.residue);

        dma_cookie_complete(&vd->tx);
        dmaengine_desc_get_callback_invoke(&vd->tx, &result);

gpi_free_desc:
        spin_lock_irqsave(&gchan->vc.lock, flags);
        list_del(&vd->node);
        spin_unlock_irqrestore(&gchan->vc.lock, flags);
        kfree(gpi_desc);
        gpi_desc = NULL;
}

/* process all events */
static void gpi_process_events(struct gpii *gpii)
{
        struct gpi_ring *ev_ring = &gpii->ev_ring;
        phys_addr_t cntxt_rp;
        void *rp;
        union gpi_event *gpi_event;
        struct gchan *gchan;
        u32 chid, type;

        cntxt_rp = gpi_read_reg(gpii, gpii->ev_ring_rp_lsb_reg);
        rp = to_virtual(ev_ring, cntxt_rp);

        do {
                while (rp != ev_ring->rp) {
                        gpi_event = ev_ring->rp;
                        chid = gpi_event->xfer_compl_event.chid;
                        type = gpi_event->xfer_compl_event.type;

                        dev_dbg(gpii->gpi_dev->dev,
                                "Event: CHID:%u, type:%x %08x %08x %08x %08x\n",
                                chid, type, gpi_event->gpi_ere.dword[0],
                                gpi_event->gpi_ere.dword[1], gpi_event->gpi_ere.dword[2],
                                gpi_event->gpi_ere.dword[3]);

                        switch (type) {
                        case XFER_COMPLETE_EV_TYPE:
                                gchan = &gpii->gchan[chid];
                                gpi_process_xfer_compl_event(gchan,
                                                             &gpi_event->xfer_compl_event);
                                break;
                        case STALE_EV_TYPE:
                                dev_dbg(gpii->gpi_dev->dev, "stale event, not processing\n");
                                break;
                        case IMMEDIATE_DATA_EV_TYPE:
                                gchan = &gpii->gchan[chid];
                                gpi_process_imed_data_event(gchan,
                                                            &gpi_event->immediate_data_event);
                                break;
                        case QUP_NOTIF_EV_TYPE:
                                dev_dbg(gpii->gpi_dev->dev, "QUP_NOTIF_EV_TYPE\n");
                                break;
                        default:
                                dev_dbg(gpii->gpi_dev->dev,
                                        "not supported event type:0x%x\n", type);
                        }
                        gpi_ring_recycle_ev_element(ev_ring);
                }
                gpi_write_ev_db(gpii, ev_ring, ev_ring->wp);

                /* clear pending IEOB events */
                gpi_write_reg(gpii, gpii->ieob_clr_reg, BIT(0));

                cntxt_rp = gpi_read_reg(gpii, gpii->ev_ring_rp_lsb_reg);
                rp = to_virtual(ev_ring, cntxt_rp);

        } while (rp != ev_ring->rp);
}

/* processing events using tasklet */
static void gpi_ev_tasklet(unsigned long data)
{
        struct gpii *gpii = (struct gpii *)data;

        read_lock(&gpii->pm_lock);
        if (!REG_ACCESS_VALID(gpii->pm_state)) {
                read_unlock(&gpii->pm_lock);
                dev_err(gpii->gpi_dev->dev, "not processing any events, pm_state:%s\n",
                        TO_GPI_PM_STR(gpii->pm_state));
                return;
        }

        /* process the events */
        gpi_process_events(gpii);

        /* enable IEOB, switching back to interrupts */
        gpi_config_interrupts(gpii, MASK_IEOB_SETTINGS, 1);
        read_unlock(&gpii->pm_lock);
}

/* marks all pending events for the channel as stale */
static void gpi_mark_stale_events(struct gchan *gchan)
{
        struct gpii *gpii = gchan->gpii;
        struct gpi_ring *ev_ring = &gpii->ev_ring;
        u32 cntxt_rp, local_rp;
        void *ev_rp;

        cntxt_rp = gpi_read_reg(gpii, gpii->ev_ring_rp_lsb_reg);

        ev_rp = ev_ring->rp;
        local_rp = (u32)to_physical(ev_ring, ev_rp);
        while (local_rp != cntxt_rp) {
                union gpi_event *gpi_event = ev_rp;
                u32 chid = gpi_event->xfer_compl_event.chid;

                if (chid == gchan->chid)
                        gpi_event->xfer_compl_event.type = STALE_EV_TYPE;
                ev_rp += ev_ring->el_size;
                if (ev_rp >= (ev_ring->base + ev_ring->len))
                        ev_rp = ev_ring->base;
                cntxt_rp = gpi_read_reg(gpii, gpii->ev_ring_rp_lsb_reg);
                local_rp = (u32)to_physical(ev_ring, ev_rp);
        }
}

/* reset sw state and issue channel reset or de-alloc */
static int gpi_reset_chan(struct gchan *gchan, enum gpi_cmd gpi_cmd)
{
        struct gpii *gpii = gchan->gpii;
        struct gpi_ring *ch_ring = &gchan->ch_ring;
        LIST_HEAD(list);
        int ret;

        ret = gpi_send_cmd(gpii, gchan, gpi_cmd);
        if (ret) {
                dev_err(gpii->gpi_dev->dev, "Error with cmd:%s ret:%d\n",
                        TO_GPI_CMD_STR(gpi_cmd), ret);
                return ret;
        }

        /* initialize the local ring ptrs */
        ch_ring->rp = ch_ring->base;
        ch_ring->wp = ch_ring->base;

        /* visible to other cores */
        smp_wmb();

        /* check event ring for any stale events */
        write_lock_irq(&gpii->pm_lock);
        gpi_mark_stale_events(gchan);

        /* remove all async descriptors */
        spin_lock(&gchan->vc.lock);
        vchan_get_all_descriptors(&gchan->vc, &list);
        spin_unlock(&gchan->vc.lock);
        write_unlock_irq(&gpii->pm_lock);
        vchan_dma_desc_free_list(&gchan->vc, &list);

        return 0;
}

static int gpi_start_chan(struct gchan *gchan)
{
        struct gpii *gpii = gchan->gpii;
        int ret;

        ret = gpi_send_cmd(gpii, gchan, GPI_CH_CMD_START);
        if (ret) {
                dev_err(gpii->gpi_dev->dev, "Error with cmd:%s ret:%d\n",
                        TO_GPI_CMD_STR(GPI_CH_CMD_START), ret);
                return ret;
        }

        /* gpii CH is active now */
        write_lock_irq(&gpii->pm_lock);
        gchan->pm_state = ACTIVE_STATE;
        write_unlock_irq(&gpii->pm_lock);

        return 0;
}

static int gpi_stop_chan(struct gchan *gchan)
{
        struct gpii *gpii = gchan->gpii;
        int ret;

        ret = gpi_send_cmd(gpii, gchan, GPI_CH_CMD_STOP);
        if (ret) {
                dev_err(gpii->gpi_dev->dev, "Error with cmd:%s ret:%d\n",
                        TO_GPI_CMD_STR(GPI_CH_CMD_STOP), ret);
                return ret;
        }

        return 0;
}

/* allocate and configure the transfer channel */
static int gpi_alloc_chan(struct gchan *chan, bool send_alloc_cmd)
{
        struct gpii *gpii = chan->gpii;
        struct gpi_ring *ring = &chan->ch_ring;
        int ret;
        u32 id = gpii->gpii_id;
        u32 chid = chan->chid;
        u32 pair_chid = !chid;

        if (send_alloc_cmd) {
                ret = gpi_send_cmd(gpii, chan, GPI_CH_CMD_ALLOCATE);
                if (ret) {
                        dev_err(gpii->gpi_dev->dev, "Error with cmd:%s ret:%d\n",
                                TO_GPI_CMD_STR(GPI_CH_CMD_ALLOCATE), ret);
                        return ret;
                }
        }

        gpi_write_reg(gpii, chan->ch_cntxt_base_reg + CNTXT_0_CONFIG,
                      GPII_n_CH_k_CNTXT_0(ring->el_size, 0, chan->dir, GPI_CHTYPE_PROTO_GPI));
        gpi_write_reg(gpii, chan->ch_cntxt_base_reg + CNTXT_1_R_LENGTH, ring->len);
        gpi_write_reg(gpii, chan->ch_cntxt_base_reg + CNTXT_2_RING_BASE_LSB, ring->phys_addr);
        gpi_write_reg(gpii, chan->ch_cntxt_base_reg + CNTXT_3_RING_BASE_MSB,
                      upper_32_bits(ring->phys_addr));
        gpi_write_reg(gpii, chan->ch_cntxt_db_reg + CNTXT_5_RING_RP_MSB - CNTXT_4_RING_RP_LSB,
                      upper_32_bits(ring->phys_addr));
        gpi_write_reg(gpii, gpii->regs + GPII_n_CH_k_SCRATCH_0_OFFS(id, chid),
                      GPII_n_CH_k_SCRATCH_0(pair_chid, chan->protocol, chan->seid));
        gpi_write_reg(gpii, gpii->regs + GPII_n_CH_k_SCRATCH_1_OFFS(id, chid), 0);
        gpi_write_reg(gpii, gpii->regs + GPII_n_CH_k_SCRATCH_2_OFFS(id, chid), 0);
        gpi_write_reg(gpii, gpii->regs + GPII_n_CH_k_SCRATCH_3_OFFS(id, chid), 0);
        gpi_write_reg(gpii, gpii->regs + GPII_n_CH_k_QOS_OFFS(id, chid), 1);

        /* flush all the writes */
        wmb();
        return 0;
}

/* allocate and configure event ring */
static int gpi_alloc_ev_chan(struct gpii *gpii)
{
        struct gpi_ring *ring = &gpii->ev_ring;
        void __iomem *base = gpii->ev_cntxt_base_reg;
        int ret;

        ret = gpi_send_cmd(gpii, NULL, GPI_EV_CMD_ALLOCATE);
        if (ret) {
                dev_err(gpii->gpi_dev->dev, "error with cmd:%s ret:%d\n",
                        TO_GPI_CMD_STR(GPI_EV_CMD_ALLOCATE), ret);
                return ret;
        }

        /* program event context */
        gpi_write_reg(gpii, base + CNTXT_0_CONFIG,
                      GPII_n_EV_k_CNTXT_0(ring->el_size, GPI_INTTYPE_IRQ, GPI_CHTYPE_GPI_EV));
        gpi_write_reg(gpii, base + CNTXT_1_R_LENGTH, ring->len);
        gpi_write_reg(gpii, base + CNTXT_2_RING_BASE_LSB, lower_32_bits(ring->phys_addr));
        gpi_write_reg(gpii, base + CNTXT_3_RING_BASE_MSB, upper_32_bits(ring->phys_addr));
        gpi_write_reg(gpii, gpii->ev_cntxt_db_reg + CNTXT_5_RING_RP_MSB - CNTXT_4_RING_RP_LSB,
                      upper_32_bits(ring->phys_addr));
        gpi_write_reg(gpii, base + CNTXT_8_RING_INT_MOD, 0);
        gpi_write_reg(gpii, base + CNTXT_10_RING_MSI_LSB, 0);
        gpi_write_reg(gpii, base + CNTXT_11_RING_MSI_MSB, 0);
        gpi_write_reg(gpii, base + CNTXT_8_RING_INT_MOD, 0);
        gpi_write_reg(gpii, base + CNTXT_12_RING_RP_UPDATE_LSB, 0);
        gpi_write_reg(gpii, base + CNTXT_13_RING_RP_UPDATE_MSB, 0);

        /* add events to ring */
        ring->wp = (ring->base + ring->len - ring->el_size);

        /* flush all the writes */
        wmb();

        /* gpii is active now */
        write_lock_irq(&gpii->pm_lock);
        gpii->pm_state = ACTIVE_STATE;
        write_unlock_irq(&gpii->pm_lock);
        gpi_write_ev_db(gpii, ring, ring->wp);

        return 0;
}

/* calculate # of ERE/TRE available to queue */
static int gpi_ring_num_elements_avail(const struct gpi_ring * const ring)
{
        int elements = 0;

        if (ring->wp < ring->rp) {
                elements = ((ring->rp - ring->wp) / ring->el_size) - 1;
        } else {
                elements = (ring->rp - ring->base) / ring->el_size;
                elements += ((ring->base + ring->len - ring->wp) / ring->el_size) - 1;
        }

        return elements;
}

static int gpi_ring_add_element(struct gpi_ring *ring, void **wp)
{
        if (gpi_ring_num_elements_avail(ring) <= 0)
                return -ENOMEM;

        *wp = ring->wp;
        ring->wp += ring->el_size;
        if (ring->wp  >= (ring->base + ring->len))
                ring->wp = ring->base;

        /* visible to other cores */
        smp_wmb();

        return 0;
}

static void gpi_ring_recycle_ev_element(struct gpi_ring *ring)
{
        /* Update the WP */
        ring->wp += ring->el_size;
        if (ring->wp  >= (ring->base + ring->len))
                ring->wp = ring->base;

        /* Update the RP */
        ring->rp += ring->el_size;
        if (ring->rp  >= (ring->base + ring->len))
                ring->rp = ring->base;

        /* visible to other cores */
        smp_wmb();
}

static void gpi_free_ring(struct gpi_ring *ring,
                          struct gpii *gpii)
{
        dma_free_coherent(gpii->gpi_dev->dev, ring->alloc_size,
                          ring->pre_aligned, ring->dma_handle);
        memset(ring, 0, sizeof(*ring));
}

/* allocate memory for transfer and event rings */
static int gpi_alloc_ring(struct gpi_ring *ring, u32 elements,
                          u32 el_size, struct gpii *gpii)
{
        u64 len = elements * el_size;
        int bit;

        /* ring len must be power of 2 */
        bit = find_last_bit((unsigned long *)&len, 32);
        if (((1 << bit) - 1) & len)
                bit++;
        len = 1 << bit;
        ring->alloc_size = (len + (len - 1));
        dev_dbg(gpii->gpi_dev->dev,
                "#el:%u el_size:%u len:%u actual_len:%llu alloc_size:%zu\n",
                  elements, el_size, (elements * el_size), len,
                  ring->alloc_size);

        ring->pre_aligned = dma_alloc_coherent(gpii->gpi_dev->dev,
                                               ring->alloc_size,
                                               &ring->dma_handle, GFP_KERNEL);
        if (!ring->pre_aligned) {
                dev_err(gpii->gpi_dev->dev, "could not alloc size:%zu mem for ring\n",
                        ring->alloc_size);
                return -ENOMEM;
        }

        /* align the physical mem */
        ring->phys_addr = (ring->dma_handle + (len - 1)) & ~(len - 1);
        ring->base = ring->pre_aligned + (ring->phys_addr - ring->dma_handle);
        ring->rp = ring->base;
        ring->wp = ring->base;
        ring->len = len;
        ring->el_size = el_size;
        ring->elements = ring->len / ring->el_size;
        memset(ring->base, 0, ring->len);
        ring->configured = true;

        /* update to other cores */
        smp_wmb();

        dev_dbg(gpii->gpi_dev->dev,
                "phy_pre:%pad phy_alig:%pa len:%u el_size:%u elements:%u\n",
                &ring->dma_handle, &ring->phys_addr, ring->len,
                ring->el_size, ring->elements);

        return 0;
}

/* copy tre into transfer ring */
static void gpi_queue_xfer(struct gpii *gpii, struct gchan *gchan,
                           struct gpi_tre *gpi_tre, void **wp)
{
        struct gpi_tre *ch_tre;
        int ret;

        /* get next tre location we can copy */
        ret = gpi_ring_add_element(&gchan->ch_ring, (void **)&ch_tre);
        if (unlikely(ret)) {
                dev_err(gpii->gpi_dev->dev, "Error adding ring element to xfer ring\n");
                return;
        }

        /* copy the tre info */
        memcpy(ch_tre, gpi_tre, sizeof(*ch_tre));
        *wp = ch_tre;
}

/* reset and restart transfer channel */
static int gpi_terminate_all(struct dma_chan *chan)
{
        struct gchan *gchan = to_gchan(chan);
        struct gpii *gpii = gchan->gpii;
        int schid, echid, i;
        int ret = 0;

        mutex_lock(&gpii->ctrl_lock);

        /*
         * treat both channels as a group if its protocol is not UART
         * STOP, RESET, or START needs to be in lockstep
         */
        schid = (gchan->protocol == QCOM_GPI_UART) ? gchan->chid : 0;
        echid = (gchan->protocol == QCOM_GPI_UART) ? schid + 1 : MAX_CHANNELS_PER_GPII;

        /* stop the channel */
        for (i = schid; i < echid; i++) {
                gchan = &gpii->gchan[i];

                /* disable ch state so no more TRE processing */
                write_lock_irq(&gpii->pm_lock);
                gchan->pm_state = PREPARE_TERMINATE;
                write_unlock_irq(&gpii->pm_lock);

                /* send command to Stop the channel */
                ret = gpi_stop_chan(gchan);
        }

        /* reset the channels (clears any pending tre) */
        for (i = schid; i < echid; i++) {
                gchan = &gpii->gchan[i];

                ret = gpi_reset_chan(gchan, GPI_CH_CMD_RESET);
                if (ret) {
                        dev_err(gpii->gpi_dev->dev, "Error resetting channel ret:%d\n", ret);
                        goto terminate_exit;
                }

                /* reprogram channel CNTXT */
                ret = gpi_alloc_chan(gchan, false);
                if (ret) {
                        dev_err(gpii->gpi_dev->dev, "Error alloc_channel ret:%d\n", ret);
                        goto terminate_exit;
                }
        }

        /* restart the channels */
        for (i = schid; i < echid; i++) {
                gchan = &gpii->gchan[i];

                ret = gpi_start_chan(gchan);
                if (ret) {
                        dev_err(gpii->gpi_dev->dev, "Error Starting Channel ret:%d\n", ret);
                        goto terminate_exit;
                }
        }

terminate_exit:
        mutex_unlock(&gpii->ctrl_lock);
        return ret;
}

/* pause dma transfer for all channels */
static int gpi_pause(struct dma_chan *chan)
{
        struct gchan *gchan = to_gchan(chan);
        struct gpii *gpii = gchan->gpii;
        int i, ret;

        mutex_lock(&gpii->ctrl_lock);

        /*
         * pause/resume are per gpii not per channel, so
         * client needs to call pause only once
         */
        if (gpii->pm_state == PAUSE_STATE) {
                dev_dbg(gpii->gpi_dev->dev, "channel is already paused\n");
                mutex_unlock(&gpii->ctrl_lock);
                return 0;
        }

        /* send stop command to stop the channels */
        for (i = 0; i < MAX_CHANNELS_PER_GPII; i++) {
                ret = gpi_stop_chan(&gpii->gchan[i]);
                if (ret) {
                        mutex_unlock(&gpii->ctrl_lock);
                        return ret;
                }
        }

        disable_irq(gpii->irq);

        /* Wait for threads to complete out */
        tasklet_kill(&gpii->ev_task);

        write_lock_irq(&gpii->pm_lock);
        gpii->pm_state = PAUSE_STATE;
        write_unlock_irq(&gpii->pm_lock);
        mutex_unlock(&gpii->ctrl_lock);

        return 0;
}

/* resume dma transfer */
static int gpi_resume(struct dma_chan *chan)
{
        struct gchan *gchan = to_gchan(chan);
        struct gpii *gpii = gchan->gpii;
        int i, ret;

        mutex_lock(&gpii->ctrl_lock);
        if (gpii->pm_state == ACTIVE_STATE) {
                dev_dbg(gpii->gpi_dev->dev, "channel is already active\n");
                mutex_unlock(&gpii->ctrl_lock);
                return 0;
        }

        enable_irq(gpii->irq);

        /* send start command to start the channels */
        for (i = 0; i < MAX_CHANNELS_PER_GPII; i++) {
                ret = gpi_send_cmd(gpii, &gpii->gchan[i], GPI_CH_CMD_START);
                if (ret) {
                        dev_err(gpii->gpi_dev->dev, "Error starting chan, ret:%d\n", ret);
                        mutex_unlock(&gpii->ctrl_lock);
                        return ret;
                }
        }

        write_lock_irq(&gpii->pm_lock);
        gpii->pm_state = ACTIVE_STATE;
        write_unlock_irq(&gpii->pm_lock);
        mutex_unlock(&gpii->ctrl_lock);

        return 0;
}

static void gpi_desc_free(struct virt_dma_desc *vd)
{
        struct gpi_desc *gpi_desc = to_gpi_desc(vd);

        kfree(gpi_desc);
        gpi_desc = NULL;
}

static int
gpi_peripheral_config(struct dma_chan *chan, struct dma_slave_config *config)
{
        struct gchan *gchan = to_gchan(chan);
        void *new_config;

        if (!config->peripheral_config)
                return -EINVAL;

        new_config = krealloc(gchan->config, config->peripheral_size, GFP_NOWAIT);
        if (!new_config)
                return -ENOMEM;

        gchan->config = new_config;
        memcpy(gchan->config, config->peripheral_config, config->peripheral_size);

        return 0;
}

static int gpi_create_i2c_tre(struct gchan *chan, struct gpi_desc *desc,
                              struct scatterlist *sgl, enum dma_transfer_direction direction,
                              unsigned long flags)
{
        struct gpi_i2c_config *i2c = chan->config;
        struct device *dev = chan->gpii->gpi_dev->dev;
        unsigned int tre_idx = 0;
        dma_addr_t address;
        struct gpi_tre *tre;
        unsigned int i;

        /* first create config tre if applicable */
        if (i2c->set_config) {
                tre = &desc->tre[tre_idx];
                tre_idx++;

                tre->dword[0] = u32_encode_bits(i2c->low_count, TRE_I2C_C0_TLOW);
                tre->dword[0] |= u32_encode_bits(i2c->high_count, TRE_I2C_C0_THIGH);
                tre->dword[0] |= u32_encode_bits(i2c->cycle_count, TRE_I2C_C0_TCYL);
                tre->dword[0] |= u32_encode_bits(i2c->pack_enable, TRE_I2C_C0_TX_PACK);
                tre->dword[0] |= u32_encode_bits(i2c->pack_enable, TRE_I2C_C0_RX_PACK);

                tre->dword[1] = 0;

                tre->dword[2] = u32_encode_bits(i2c->clk_div, TRE_C0_CLK_DIV);

                tre->dword[3] = u32_encode_bits(TRE_TYPE_CONFIG0, TRE_FLAGS_TYPE);
                tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_CHAIN);
        }

        /* create the GO tre for Tx */
        if (i2c->op == I2C_WRITE) {
                tre = &desc->tre[tre_idx];
                tre_idx++;

                if (i2c->multi_msg)
                        tre->dword[0] = u32_encode_bits(I2C_READ, TRE_I2C_GO_CMD);
                else
                        tre->dword[0] = u32_encode_bits(i2c->op, TRE_I2C_GO_CMD);

                tre->dword[0] |= u32_encode_bits(i2c->addr, TRE_I2C_GO_ADDR);
                tre->dword[0] |= u32_encode_bits(i2c->stretch, TRE_I2C_GO_STRETCH);

                tre->dword[1] = 0;
                tre->dword[2] = u32_encode_bits(i2c->rx_len, TRE_RX_LEN);

                tre->dword[3] = u32_encode_bits(TRE_TYPE_GO, TRE_FLAGS_TYPE);

                if (i2c->multi_msg)
                        tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_LINK);
                else
                        tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_CHAIN);
        }

        if (i2c->op == I2C_READ || i2c->multi_msg == false) {
                /* create the DMA TRE */
                tre = &desc->tre[tre_idx];
                tre_idx++;

                address = sg_dma_address(sgl);
                tre->dword[0] = lower_32_bits(address);
                tre->dword[1] = upper_32_bits(address);

                tre->dword[2] = u32_encode_bits(sg_dma_len(sgl), TRE_DMA_LEN);

                tre->dword[3] = u32_encode_bits(TRE_TYPE_DMA, TRE_FLAGS_TYPE);
                tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_IEOT);

                if (!(flags & DMA_PREP_INTERRUPT))
                        tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_BEI);
        }

        for (i = 0; i < tre_idx; i++)
                dev_dbg(dev, "TRE:%d %x:%x:%x:%x\n", i, desc->tre[i].dword[0],
                        desc->tre[i].dword[1], desc->tre[i].dword[2], desc->tre[i].dword[3]);

        return tre_idx;
}

static int gpi_create_spi_tre(struct gchan *chan, struct gpi_desc *desc,
                              struct scatterlist *sgl, enum dma_transfer_direction direction)
{
        struct gpi_spi_config *spi = chan->config;
        struct device *dev = chan->gpii->gpi_dev->dev;
        unsigned int tre_idx = 0;
        dma_addr_t address;
        struct gpi_tre *tre;
        unsigned int i;
        int len;

        /* first create config tre if applicable */
        if (direction == DMA_MEM_TO_DEV && spi->set_config) {
                tre = &desc->tre[tre_idx];
                tre_idx++;

                tre->dword[0] = u32_encode_bits(spi->word_len, TRE_SPI_C0_WORD_SZ);
                tre->dword[0] |= u32_encode_bits(spi->loopback_en, TRE_SPI_C0_LOOPBACK);
                tre->dword[0] |= u32_encode_bits(spi->clock_pol_high, TRE_SPI_C0_CPOL);
                tre->dword[0] |= u32_encode_bits(spi->data_pol_high, TRE_SPI_C0_CPHA);
                tre->dword[0] |= u32_encode_bits(spi->pack_en, TRE_SPI_C0_TX_PACK);
                tre->dword[0] |= u32_encode_bits(spi->pack_en, TRE_SPI_C0_RX_PACK);

                tre->dword[1] = 0;

                tre->dword[2] = u32_encode_bits(spi->clk_div, TRE_C0_CLK_DIV);
                tre->dword[2] |= u32_encode_bits(spi->clk_src, TRE_C0_CLK_SRC);

                tre->dword[3] = u32_encode_bits(TRE_TYPE_CONFIG0, TRE_FLAGS_TYPE);
                tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_CHAIN);
        }

        /* create the GO tre for Tx */
        if (direction == DMA_MEM_TO_DEV) {
                tre = &desc->tre[tre_idx];
                tre_idx++;

                tre->dword[0] = u32_encode_bits(spi->fragmentation, TRE_SPI_GO_FRAG);
                tre->dword[0] |= u32_encode_bits(spi->cs, TRE_SPI_GO_CS);
                tre->dword[0] |= u32_encode_bits(spi->cmd, TRE_SPI_GO_CMD);

                tre->dword[1] = 0;

                tre->dword[2] = u32_encode_bits(spi->rx_len, TRE_RX_LEN);

                tre->dword[3] = u32_encode_bits(TRE_TYPE_GO, TRE_FLAGS_TYPE);
                if (spi->cmd == SPI_RX) {
                        tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_IEOB);
                        tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_LINK);
                } else if (spi->cmd == SPI_TX) {
                        tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_CHAIN);
                } else { /* SPI_DUPLEX */
                        tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_CHAIN);
                        tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_LINK);
                }
        }

        /* create the dma tre */
        tre = &desc->tre[tre_idx];
        tre_idx++;

        address = sg_dma_address(sgl);
        len = sg_dma_len(sgl);

        /* Support Immediate dma for write transfers for data length up to 8 bytes */
        if (direction == DMA_MEM_TO_DEV && len <= 2 * sizeof(tre->dword[0])) {
                /*
                 * For Immediate dma, data length may not always be length of 8 bytes,
                 * it can be length less than 8, hence initialize both dword's with 0
                 */
                tre->dword[0] = 0;
                tre->dword[1] = 0;
                memcpy(&tre->dword[0], sg_virt(sgl), len);

                tre->dword[2] = u32_encode_bits(len, TRE_DMA_IMMEDIATE_LEN);
                tre->dword[3] = u32_encode_bits(TRE_TYPE_IMMEDIATE_DMA, TRE_FLAGS_TYPE);
        } else {
                tre->dword[0] = lower_32_bits(address);
                tre->dword[1] = upper_32_bits(address);

                tre->dword[2] = u32_encode_bits(len, TRE_DMA_LEN);
                tre->dword[3] = u32_encode_bits(TRE_TYPE_DMA, TRE_FLAGS_TYPE);
        }

        tre->dword[3] |= u32_encode_bits(direction == DMA_MEM_TO_DEV,
                                         TRE_FLAGS_IEOT);

        for (i = 0; i < tre_idx; i++)
                dev_dbg(dev, "TRE:%d %x:%x:%x:%x\n", i, desc->tre[i].dword[0],
                        desc->tre[i].dword[1], desc->tre[i].dword[2], desc->tre[i].dword[3]);

        return tre_idx;
}

/* copy tre into transfer ring */
static struct dma_async_tx_descriptor *
gpi_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
                  unsigned int sg_len, enum dma_transfer_direction direction,
                  unsigned long flags, void *context)
{
        struct gchan *gchan = to_gchan(chan);
        struct gpii *gpii = gchan->gpii;
        struct device *dev = gpii->gpi_dev->dev;
        struct gpi_ring *ch_ring = &gchan->ch_ring;
        struct gpi_desc *gpi_desc;
        u32 nr, nr_tre = 0;
        u8 set_config;
        int i;

        gpii->ieob_set = false;
        if (!is_slave_direction(direction)) {
                dev_err(gpii->gpi_dev->dev, "invalid dma direction: %d\n", direction);
                return NULL;
        }

        if (sg_len > 1) {
                dev_err(dev, "Multi sg sent, we support only one atm: %d\n", sg_len);
                return NULL;
        }

        nr_tre = 3;
        set_config = *(u32 *)gchan->config;
        if (!set_config)
                nr_tre = 2;
        if (direction == DMA_DEV_TO_MEM) /* rx */
                nr_tre = 1;

        /* calculate # of elements required & available */
        nr = gpi_ring_num_elements_avail(ch_ring);
        if (nr < nr_tre) {
                dev_err(dev, "not enough space in ring, avail:%u required:%u\n", nr, nr_tre);
                return NULL;
        }

        if (!(flags & DMA_PREP_INTERRUPT) && (nr - nr_tre < 2))
                return NULL;

        gpi_desc = kzalloc_obj(*gpi_desc, GFP_NOWAIT);
        if (!gpi_desc)
                return NULL;

        /* create TREs for xfer */
        if (gchan->protocol == QCOM_GPI_SPI) {
                i = gpi_create_spi_tre(gchan, gpi_desc, sgl, direction);
        } else if (gchan->protocol == QCOM_GPI_I2C) {
                i = gpi_create_i2c_tre(gchan, gpi_desc, sgl, direction, flags);
        } else {
                dev_err(dev, "invalid peripheral: %d\n", gchan->protocol);
                kfree(gpi_desc);
                return NULL;
        }

        /* set up the descriptor */
        gpi_desc->gchan = gchan;
        gpi_desc->len = sg_dma_len(sgl);
        gpi_desc->num_tre  = i;

        return vchan_tx_prep(&gchan->vc, &gpi_desc->vd, flags);
}

/* rings transfer ring db to being transfer */
static void gpi_issue_pending(struct dma_chan *chan)
{
        struct gchan *gchan = to_gchan(chan);
        struct gpii *gpii = gchan->gpii;
        unsigned long flags, pm_lock_flags;
        struct virt_dma_desc *vd = NULL;
        struct gpi_desc *gpi_desc;
        struct gpi_ring *ch_ring = &gchan->ch_ring;
        void *tre, *wp = NULL;
        int i;

        read_lock_irqsave(&gpii->pm_lock, pm_lock_flags);

        /* move all submitted descriptors to issued list */
        spin_lock_irqsave(&gchan->vc.lock, flags);
        if (vchan_issue_pending(&gchan->vc))
                vd = list_last_entry(&gchan->vc.desc_issued,
                                     struct virt_dma_desc, node);
        spin_unlock_irqrestore(&gchan->vc.lock, flags);

        /* nothing to do list is empty */
        if (!vd) {
                read_unlock_irqrestore(&gpii->pm_lock, pm_lock_flags);
                return;
        }

        gpi_desc = to_gpi_desc(vd);
        for (i = 0; i < gpi_desc->num_tre; i++) {
                tre = &gpi_desc->tre[i];
                gpi_queue_xfer(gpii, gchan, tre, &wp);
        }

        gpi_desc->db = ch_ring->wp;
        gpi_write_ch_db(gchan, &gchan->ch_ring, gpi_desc->db);
        read_unlock_irqrestore(&gpii->pm_lock, pm_lock_flags);
}

static int gpi_ch_init(struct gchan *gchan)
{
        struct gpii *gpii = gchan->gpii;
        const int ev_factor = gpii->gpi_dev->ev_factor;
        u32 elements;
        int i = 0, ret = 0;

        gchan->pm_state = CONFIG_STATE;

        /* check if both channels are configured before continue */
        for (i = 0; i < MAX_CHANNELS_PER_GPII; i++)
                if (gpii->gchan[i].pm_state != CONFIG_STATE)
                        goto exit_gpi_init;

        /* protocol must be same for both channels */
        if (gpii->gchan[0].protocol != gpii->gchan[1].protocol) {
                dev_err(gpii->gpi_dev->dev, "protocol did not match protocol %u != %u\n",
                        gpii->gchan[0].protocol, gpii->gchan[1].protocol);
                ret = -EINVAL;
                goto exit_gpi_init;
        }

        /* allocate memory for event ring */
        elements = CHAN_TRES << ev_factor;
        ret = gpi_alloc_ring(&gpii->ev_ring, elements,
                             sizeof(union gpi_event), gpii);
        if (ret)
                goto exit_gpi_init;

        /* configure interrupts */
        write_lock_irq(&gpii->pm_lock);
        gpii->pm_state = PREPARE_HARDWARE;
        write_unlock_irq(&gpii->pm_lock);
        ret = gpi_config_interrupts(gpii, DEFAULT_IRQ_SETTINGS, 0);
        if (ret) {
                dev_err(gpii->gpi_dev->dev, "error config. interrupts, ret:%d\n", ret);
                goto error_config_int;
        }

        /* allocate event rings */
        ret = gpi_alloc_ev_chan(gpii);
        if (ret) {
                dev_err(gpii->gpi_dev->dev, "error alloc_ev_chan:%d\n", ret);
                goto error_alloc_ev_ring;
        }

        /* Allocate all channels */
        for (i = 0; i < MAX_CHANNELS_PER_GPII; i++) {
                ret = gpi_alloc_chan(&gpii->gchan[i], true);
                if (ret) {
                        dev_err(gpii->gpi_dev->dev, "Error allocating chan:%d\n", ret);
                        goto error_alloc_chan;
                }
        }

        /* start channels  */
        for (i = 0; i < MAX_CHANNELS_PER_GPII; i++) {
                ret = gpi_start_chan(&gpii->gchan[i]);
                if (ret) {
                        dev_err(gpii->gpi_dev->dev, "Error start chan:%d\n", ret);
                        goto error_start_chan;
                }
        }
        return ret;

error_start_chan:
        for (i = i - 1; i >= 0; i--) {
                gpi_stop_chan(&gpii->gchan[i]);
                gpi_send_cmd(gpii, gchan, GPI_CH_CMD_RESET);
        }
        i = 2;
error_alloc_chan:
        for (i = i - 1; i >= 0; i--)
                gpi_reset_chan(gchan, GPI_CH_CMD_DE_ALLOC);
error_alloc_ev_ring:
        gpi_disable_interrupts(gpii);
error_config_int:
        gpi_free_ring(&gpii->ev_ring, gpii);
exit_gpi_init:
        return ret;
}

/* release all channel resources */
static void gpi_free_chan_resources(struct dma_chan *chan)
{
        struct gchan *gchan = to_gchan(chan);
        struct gpii *gpii = gchan->gpii;
        enum gpi_pm_state cur_state;
        int ret, i;

        mutex_lock(&gpii->ctrl_lock);

        cur_state = gchan->pm_state;

        /* disable ch state so no more TRE processing for this channel */
        write_lock_irq(&gpii->pm_lock);
        gchan->pm_state = PREPARE_TERMINATE;
        write_unlock_irq(&gpii->pm_lock);

        /* attempt to do graceful hardware shutdown */
        if (cur_state == ACTIVE_STATE) {
                gpi_stop_chan(gchan);

                ret = gpi_send_cmd(gpii, gchan, GPI_CH_CMD_RESET);
                if (ret)
                        dev_err(gpii->gpi_dev->dev, "error resetting channel:%d\n", ret);

                gpi_reset_chan(gchan, GPI_CH_CMD_DE_ALLOC);
        }

        /* free all allocated memory */
        gpi_free_ring(&gchan->ch_ring, gpii);
        vchan_free_chan_resources(&gchan->vc);
        kfree(gchan->config);

        write_lock_irq(&gpii->pm_lock);
        gchan->pm_state = DISABLE_STATE;
        write_unlock_irq(&gpii->pm_lock);

        /* if other rings are still active exit */
        for (i = 0; i < MAX_CHANNELS_PER_GPII; i++)
                if (gpii->gchan[i].ch_ring.configured)
                        goto exit_free;

        /* deallocate EV Ring */
        cur_state = gpii->pm_state;
        write_lock_irq(&gpii->pm_lock);
        gpii->pm_state = PREPARE_TERMINATE;
        write_unlock_irq(&gpii->pm_lock);

        /* wait for threads to complete out */
        tasklet_kill(&gpii->ev_task);

        /* send command to de allocate event ring */
        if (cur_state == ACTIVE_STATE)
                gpi_send_cmd(gpii, NULL, GPI_EV_CMD_DEALLOC);

        gpi_free_ring(&gpii->ev_ring, gpii);

        /* disable interrupts */
        if (cur_state == ACTIVE_STATE)
                gpi_disable_interrupts(gpii);

        /* set final state to disable */
        write_lock_irq(&gpii->pm_lock);
        gpii->pm_state = DISABLE_STATE;
        write_unlock_irq(&gpii->pm_lock);

exit_free:
        mutex_unlock(&gpii->ctrl_lock);
}

/* allocate channel resources */
static int gpi_alloc_chan_resources(struct dma_chan *chan)
{
        struct gchan *gchan = to_gchan(chan);
        struct gpii *gpii = gchan->gpii;
        int ret;

        mutex_lock(&gpii->ctrl_lock);

        /* allocate memory for transfer ring */
        ret = gpi_alloc_ring(&gchan->ch_ring, CHAN_TRES,
                             sizeof(struct gpi_tre), gpii);
        if (ret)
                goto xfer_alloc_err;

        ret = gpi_ch_init(gchan);

        mutex_unlock(&gpii->ctrl_lock);

        return ret;
xfer_alloc_err:
        mutex_unlock(&gpii->ctrl_lock);

        return ret;
}

static int gpi_find_avail_gpii(struct gpi_dev *gpi_dev, u32 seid)
{
        struct gchan *tx_chan, *rx_chan;
        unsigned int gpii;

        /* check if same seid is already configured for another chid */
        for (gpii = 0; gpii < gpi_dev->max_gpii; gpii++) {
                if (!((1 << gpii) & gpi_dev->gpii_mask))
                        continue;

                tx_chan = &gpi_dev->gpiis[gpii].gchan[GPI_TX_CHAN];
                rx_chan = &gpi_dev->gpiis[gpii].gchan[GPI_RX_CHAN];

                if (rx_chan->vc.chan.client_count && rx_chan->seid == seid)
                        return gpii;
                if (tx_chan->vc.chan.client_count && tx_chan->seid == seid)
                        return gpii;
        }

        /* no channels configured with same seid, return next avail gpii */
        for (gpii = 0; gpii < gpi_dev->max_gpii; gpii++) {
                if (!((1 << gpii) & gpi_dev->gpii_mask))
                        continue;

                tx_chan = &gpi_dev->gpiis[gpii].gchan[GPI_TX_CHAN];
                rx_chan = &gpi_dev->gpiis[gpii].gchan[GPI_RX_CHAN];

                /* check if gpii is configured */
                if (tx_chan->vc.chan.client_count ||
                    rx_chan->vc.chan.client_count)
                        continue;

                /* found a free gpii */
                return gpii;
        }

        /* no gpii instance available to use */
        return -EIO;
}

/* gpi_of_dma_xlate: open client requested channel */
static struct dma_chan *gpi_of_dma_xlate(struct of_phandle_args *args,
                                         struct of_dma *of_dma)
{
        struct gpi_dev *gpi_dev = (struct gpi_dev *)of_dma->of_dma_data;
        u32 seid, chid;
        int gpii;
        struct gchan *gchan;

        if (args->args_count < 3) {
                dev_err(gpi_dev->dev, "gpii require minimum 2 args, client passed:%d args\n",
                        args->args_count);
                return NULL;
        }

        chid = args->args[0];
        if (chid >= MAX_CHANNELS_PER_GPII) {
                dev_err(gpi_dev->dev, "gpii channel:%d not valid\n", chid);
                return NULL;
        }

        seid = args->args[1];

        /* find next available gpii to use */
        gpii = gpi_find_avail_gpii(gpi_dev, seid);
        if (gpii < 0) {
                dev_err(gpi_dev->dev, "no available gpii instances\n");
                return NULL;
        }

        gchan = &gpi_dev->gpiis[gpii].gchan[chid];
        if (gchan->vc.chan.client_count) {
                dev_err(gpi_dev->dev, "gpii:%d chid:%d seid:%d already configured\n",
                        gpii, chid, gchan->seid);
                return NULL;
        }

        gchan->seid = seid;
        gchan->protocol = args->args[2];

        return dma_get_slave_channel(&gchan->vc.chan);
}

static int gpi_probe(struct platform_device *pdev)
{
        struct gpi_dev *gpi_dev;
        unsigned int i;
        u32 ee_offset;
        int ret;

        gpi_dev = devm_kzalloc(&pdev->dev, sizeof(*gpi_dev), GFP_KERNEL);
        if (!gpi_dev)
                return -ENOMEM;

        gpi_dev->dev = &pdev->dev;
        gpi_dev->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &gpi_dev->res);
        if (IS_ERR(gpi_dev->regs))
                return PTR_ERR(gpi_dev->regs);
        gpi_dev->ee_base = gpi_dev->regs;

        ret = of_property_read_u32(gpi_dev->dev->of_node, "dma-channels",
                                   &gpi_dev->max_gpii);
        if (ret) {
                dev_err(gpi_dev->dev, "missing 'max-no-gpii' DT node\n");
                return ret;
        }

        ret = of_property_read_u32(gpi_dev->dev->of_node, "dma-channel-mask",
                                   &gpi_dev->gpii_mask);
        if (ret) {
                dev_err(gpi_dev->dev, "missing 'gpii-mask' DT node\n");
                return ret;
        }

        ee_offset = (uintptr_t)device_get_match_data(gpi_dev->dev);
        gpi_dev->ee_base = gpi_dev->ee_base - ee_offset;

        gpi_dev->ev_factor = EV_FACTOR;

        ret = dma_set_mask(gpi_dev->dev, DMA_BIT_MASK(64));
        if (ret) {
                dev_err(gpi_dev->dev, "Error setting dma_mask to 64, ret:%d\n", ret);
                return ret;
        }

        gpi_dev->gpiis = devm_kzalloc(gpi_dev->dev, sizeof(*gpi_dev->gpiis) *
                                      gpi_dev->max_gpii, GFP_KERNEL);
        if (!gpi_dev->gpiis)
                return -ENOMEM;

        /* setup all the supported gpii */
        INIT_LIST_HEAD(&gpi_dev->dma_device.channels);
        for (i = 0; i < gpi_dev->max_gpii; i++) {
                struct gpii *gpii = &gpi_dev->gpiis[i];
                int chan;

                if (!((1 << i) & gpi_dev->gpii_mask))
                        continue;

                /* set up ev cntxt register map */
                gpii->ev_cntxt_base_reg = gpi_dev->ee_base + GPII_n_EV_CH_k_CNTXT_0_OFFS(i, 0);
                gpii->ev_cntxt_db_reg = gpi_dev->ee_base + GPII_n_EV_CH_k_DOORBELL_0_OFFS(i, 0);
                gpii->ev_ring_rp_lsb_reg = gpii->ev_cntxt_base_reg + CNTXT_4_RING_RP_LSB;
                gpii->ev_cmd_reg = gpi_dev->ee_base + GPII_n_EV_CH_CMD_OFFS(i);
                gpii->ieob_clr_reg = gpi_dev->ee_base + GPII_n_CNTXT_SRC_IEOB_IRQ_CLR_OFFS(i);

                /* set up irq */
                ret = platform_get_irq(pdev, i);
                if (ret < 0)
                        return ret;
                gpii->irq = ret;

                /* set up channel specific register info */
                for (chan = 0; chan < MAX_CHANNELS_PER_GPII; chan++) {
                        struct gchan *gchan = &gpii->gchan[chan];

                        /* set up ch cntxt register map */
                        gchan->ch_cntxt_base_reg = gpi_dev->ee_base +
                                GPII_n_CH_k_CNTXT_0_OFFS(i, chan);
                        gchan->ch_cntxt_db_reg = gpi_dev->ee_base +
                                GPII_n_CH_k_DOORBELL_0_OFFS(i, chan);
                        gchan->ch_cmd_reg = gpi_dev->ee_base + GPII_n_CH_CMD_OFFS(i);

                        /* vchan setup */
                        vchan_init(&gchan->vc, &gpi_dev->dma_device);
                        gchan->vc.desc_free = gpi_desc_free;
                        gchan->chid = chan;
                        gchan->gpii = gpii;
                        gchan->dir = GPII_CHAN_DIR[chan];
                }
                mutex_init(&gpii->ctrl_lock);
                rwlock_init(&gpii->pm_lock);
                tasklet_init(&gpii->ev_task, gpi_ev_tasklet,
                             (unsigned long)gpii);
                init_completion(&gpii->cmd_completion);
                gpii->gpii_id = i;
                gpii->regs = gpi_dev->ee_base;
                gpii->gpi_dev = gpi_dev;
        }

        platform_set_drvdata(pdev, gpi_dev);

        /* clear and Set capabilities */
        dma_cap_zero(gpi_dev->dma_device.cap_mask);
        dma_cap_set(DMA_SLAVE, gpi_dev->dma_device.cap_mask);

        /* configure dmaengine apis */
        gpi_dev->dma_device.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
        gpi_dev->dma_device.residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
        gpi_dev->dma_device.src_addr_widths = DMA_SLAVE_BUSWIDTH_8_BYTES;
        gpi_dev->dma_device.dst_addr_widths = DMA_SLAVE_BUSWIDTH_8_BYTES;
        gpi_dev->dma_device.device_alloc_chan_resources = gpi_alloc_chan_resources;
        gpi_dev->dma_device.device_free_chan_resources = gpi_free_chan_resources;
        gpi_dev->dma_device.device_tx_status = dma_cookie_status;
        gpi_dev->dma_device.device_issue_pending = gpi_issue_pending;
        gpi_dev->dma_device.device_prep_slave_sg = gpi_prep_slave_sg;
        gpi_dev->dma_device.device_config = gpi_peripheral_config;
        gpi_dev->dma_device.device_terminate_all = gpi_terminate_all;
        gpi_dev->dma_device.dev = gpi_dev->dev;
        gpi_dev->dma_device.device_pause = gpi_pause;
        gpi_dev->dma_device.device_resume = gpi_resume;

        /* register with dmaengine framework */
        ret = dma_async_device_register(&gpi_dev->dma_device);
        if (ret) {
                dev_err(gpi_dev->dev, "async_device_register failed ret:%d", ret);
                return ret;
        }

        ret = of_dma_controller_register(gpi_dev->dev->of_node,
                                         gpi_of_dma_xlate, gpi_dev);
        if (ret) {
                dev_err(gpi_dev->dev, "of_dma_controller_reg failed ret:%d", ret);
                return ret;
        }

        return ret;
}

static const struct of_device_id gpi_of_match[] = {
        { .compatible = "qcom,sdm845-gpi-dma", .data = (void *)0x0 },
        { .compatible = "qcom,sm6350-gpi-dma", .data = (void *)0x10000 },
        /*
         * Do not grow the list for compatible devices. Instead use
         * qcom,sdm845-gpi-dma (for ee_offset = 0x0) or qcom,sm6350-gpi-dma
         * (for ee_offset = 0x10000).
         */
        { .compatible = "qcom,sc7280-gpi-dma", .data = (void *)0x10000 },
        { .compatible = "qcom,sm8150-gpi-dma", .data = (void *)0x0 },
        { .compatible = "qcom,sm8250-gpi-dma", .data = (void *)0x0 },
        { .compatible = "qcom,sm8350-gpi-dma", .data = (void *)0x10000 },
        { .compatible = "qcom,sm8450-gpi-dma", .data = (void *)0x10000 },
        { },
};
MODULE_DEVICE_TABLE(of, gpi_of_match);

static struct platform_driver gpi_driver = {
        .probe = gpi_probe,
        .driver = {
                .name = KBUILD_MODNAME,
                .of_match_table = gpi_of_match,
        },
};

static int __init gpi_init(void)
{
        return platform_driver_register(&gpi_driver);
}
subsys_initcall(gpi_init)

MODULE_DESCRIPTION("QCOM GPI DMA engine driver");
MODULE_LICENSE("GPL v2");