// SPDX-License-Identifier: GPL-2.0+
// Copyright 2018 IBM Corp
/*
 * A FSI master based on Aspeed ColdFire coprocessor
 */

#include <linux/crc4.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/fsi.h>
#include <linux/gpio/consumer.h>
#include <linux/io.h>
#include <linux/irqflags.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_reserved_mem.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/regmap.h>
#include <linux/firmware.h>
#include <linux/gpio/aspeed.h>
#include <linux/mfd/syscon.h>
#include <linux/genalloc.h>

#include "fsi-master.h"
#include "cf-fsi-fw.h"

#define FW_FILE_NAME    "cf-fsi-fw.bin"

/* Common SCU based coprocessor control registers */
#define SCU_COPRO_CTRL                  0x100
#define   SCU_COPRO_RESET                       0x00000002
#define   SCU_COPRO_CLK_EN                      0x00000001

/* AST2500 specific ones */
#define SCU_2500_COPRO_SEG0             0x104
#define SCU_2500_COPRO_SEG1             0x108
#define SCU_2500_COPRO_SEG2             0x10c
#define SCU_2500_COPRO_SEG3             0x110
#define SCU_2500_COPRO_SEG4             0x114
#define SCU_2500_COPRO_SEG5             0x118
#define SCU_2500_COPRO_SEG6             0x11c
#define SCU_2500_COPRO_SEG7             0x120
#define SCU_2500_COPRO_SEG8             0x124
#define   SCU_2500_COPRO_SEG_SWAP               0x00000001
#define SCU_2500_COPRO_CACHE_CTL        0x128
#define   SCU_2500_COPRO_CACHE_EN               0x00000001
#define   SCU_2500_COPRO_SEG0_CACHE_EN          0x00000002
#define   SCU_2500_COPRO_SEG1_CACHE_EN          0x00000004
#define   SCU_2500_COPRO_SEG2_CACHE_EN          0x00000008
#define   SCU_2500_COPRO_SEG3_CACHE_EN          0x00000010
#define   SCU_2500_COPRO_SEG4_CACHE_EN          0x00000020
#define   SCU_2500_COPRO_SEG5_CACHE_EN          0x00000040
#define   SCU_2500_COPRO_SEG6_CACHE_EN          0x00000080
#define   SCU_2500_COPRO_SEG7_CACHE_EN          0x00000100
#define   SCU_2500_COPRO_SEG8_CACHE_EN          0x00000200

#define SCU_2400_COPRO_SEG0             0x104
#define SCU_2400_COPRO_SEG2             0x108
#define SCU_2400_COPRO_SEG4             0x10c
#define SCU_2400_COPRO_SEG6             0x110
#define SCU_2400_COPRO_SEG8             0x114
#define   SCU_2400_COPRO_SEG_SWAP               0x80000000
#define SCU_2400_COPRO_CACHE_CTL        0x118
#define   SCU_2400_COPRO_CACHE_EN               0x00000001
#define   SCU_2400_COPRO_SEG0_CACHE_EN          0x00000002
#define   SCU_2400_COPRO_SEG2_CACHE_EN          0x00000004
#define   SCU_2400_COPRO_SEG4_CACHE_EN          0x00000008
#define   SCU_2400_COPRO_SEG6_CACHE_EN          0x00000010
#define   SCU_2400_COPRO_SEG8_CACHE_EN          0x00000020

/* CVIC registers */
#define CVIC_EN_REG                     0x10
#define CVIC_TRIG_REG                   0x18

/*
 * System register base address (needed for configuring the
 * coldfire maps)
 */
#define SYSREG_BASE                     0x1e600000

/* Amount of SRAM required */
#define SRAM_SIZE                       0x1000

#define LAST_ADDR_INVALID               0x1

struct fsi_master_acf {
        struct fsi_master       master;
        struct device           *dev;
        struct regmap           *scu;
        struct mutex            lock;   /* mutex for command ordering */
        struct gpio_desc        *gpio_clk;
        struct gpio_desc        *gpio_data;
        struct gpio_desc        *gpio_trans;    /* Voltage translator */
        struct gpio_desc        *gpio_enable;   /* FSI enable */
        struct gpio_desc        *gpio_mux;      /* Mux control */
        uint16_t                gpio_clk_vreg;
        uint16_t                gpio_clk_dreg;
        uint16_t                gpio_dat_vreg;
        uint16_t                gpio_dat_dreg;
        uint16_t                gpio_tra_vreg;
        uint16_t                gpio_tra_dreg;
        uint8_t                 gpio_clk_bit;
        uint8_t                 gpio_dat_bit;
        uint8_t                 gpio_tra_bit;
        uint32_t                cf_mem_addr;
        size_t                  cf_mem_size;
        void __iomem            *cf_mem;
        void __iomem            *cvic;
        struct gen_pool         *sram_pool;
        void __iomem            *sram;
        bool                    is_ast2500;
        bool                    external_mode;
        bool                    trace_enabled;
        uint32_t                last_addr;
        uint8_t                 t_send_delay;
        uint8_t                 t_echo_delay;
        uint32_t                cvic_sw_irq;
};
#define to_fsi_master_acf(m) container_of(m, struct fsi_master_acf, master)

struct fsi_msg {
        uint64_t        msg;
        uint8_t         bits;
};

#define CREATE_TRACE_POINTS
#include <trace/events/fsi_master_ast_cf.h>

static void msg_push_bits(struct fsi_msg *msg, uint64_t data, int bits)
{
        msg->msg <<= bits;
        msg->msg |= data & ((1ull << bits) - 1);
        msg->bits += bits;
}

static void msg_push_crc(struct fsi_msg *msg)
{
        uint8_t crc;
        int top;

        top = msg->bits & 0x3;

        /* start bit, and any non-aligned top bits */
        crc = crc4(0, 1 << top | msg->msg >> (msg->bits - top), top + 1);

        /* aligned bits */
        crc = crc4(crc, msg->msg, msg->bits - top);

        msg_push_bits(msg, crc, 4);
}

static void msg_finish_cmd(struct fsi_msg *cmd)
{
        /* Left align message */
        cmd->msg <<= (64 - cmd->bits);
}

static bool check_same_address(struct fsi_master_acf *master, int id,
                               uint32_t addr)
{
        /* this will also handle LAST_ADDR_INVALID */
        return master->last_addr == (((id & 0x3) << 21) | (addr & ~0x3));
}

static bool check_relative_address(struct fsi_master_acf *master, int id,
                                   uint32_t addr, uint32_t *rel_addrp)
{
        uint32_t last_addr = master->last_addr;
        int32_t rel_addr;

        if (last_addr == LAST_ADDR_INVALID)
                return false;

        /* We may be in 23-bit addressing mode, which uses the id as the
         * top two address bits. So, if we're referencing a different ID,
         * use absolute addresses.
         */
        if (((last_addr >> 21) & 0x3) != id)
                return false;

        /* remove the top two bits from any 23-bit addressing */
        last_addr &= (1 << 21) - 1;

        /* We know that the addresses are limited to 21 bits, so this won't
         * overflow the signed rel_addr */
        rel_addr = addr - last_addr;
        if (rel_addr > 255 || rel_addr < -256)
                return false;

        *rel_addrp = (uint32_t)rel_addr;

        return true;
}

static void last_address_update(struct fsi_master_acf *master,
                                int id, bool valid, uint32_t addr)
{
        if (!valid)
                master->last_addr = LAST_ADDR_INVALID;
        else
                master->last_addr = ((id & 0x3) << 21) | (addr & ~0x3);
}

/*
 * Encode an Absolute/Relative/Same Address command
 */
static void build_ar_command(struct fsi_master_acf *master,
                             struct fsi_msg *cmd, uint8_t id,
                             uint32_t addr, size_t size,
                             const void *data)
{
        int i, addr_bits, opcode_bits;
        bool write = !!data;
        uint8_t ds, opcode;
        uint32_t rel_addr;

        cmd->bits = 0;
        cmd->msg = 0;

        /* we have 21 bits of address max */
        addr &= ((1 << 21) - 1);

        /* cmd opcodes are variable length - SAME_AR is only two bits */
        opcode_bits = 3;

        if (check_same_address(master, id, addr)) {
                /* we still address the byte offset within the word */
                addr_bits = 2;
                opcode_bits = 2;
                opcode = FSI_CMD_SAME_AR;
                trace_fsi_master_acf_cmd_same_addr(master);

        } else if (check_relative_address(master, id, addr, &rel_addr)) {
                /* 8 bits plus sign */
                addr_bits = 9;
                addr = rel_addr;
                opcode = FSI_CMD_REL_AR;
                trace_fsi_master_acf_cmd_rel_addr(master, rel_addr);

        } else {
                addr_bits = 21;
                opcode = FSI_CMD_ABS_AR;
                trace_fsi_master_acf_cmd_abs_addr(master, addr);
        }

        /*
         * The read/write size is encoded in the lower bits of the address
         * (as it must be naturally-aligned), and the following ds bit.
         *
         *      size    addr:1  addr:0  ds
         *      1       x       x       0
         *      2       x       0       1
         *      4       0       1       1
         *
         */
        ds = size > 1 ? 1 : 0;
        addr &= ~(size - 1);
        if (size == 4)
                addr |= 1;

        msg_push_bits(cmd, id, 2);
        msg_push_bits(cmd, opcode, opcode_bits);
        msg_push_bits(cmd, write ? 0 : 1, 1);
        msg_push_bits(cmd, addr, addr_bits);
        msg_push_bits(cmd, ds, 1);
        for (i = 0; write && i < size; i++)
                msg_push_bits(cmd, ((uint8_t *)data)[i], 8);

        msg_push_crc(cmd);
        msg_finish_cmd(cmd);
}

static void build_dpoll_command(struct fsi_msg *cmd, uint8_t slave_id)
{
        cmd->bits = 0;
        cmd->msg = 0;

        msg_push_bits(cmd, slave_id, 2);
        msg_push_bits(cmd, FSI_CMD_DPOLL, 3);
        msg_push_crc(cmd);
        msg_finish_cmd(cmd);
}

static void build_epoll_command(struct fsi_msg *cmd, uint8_t slave_id)
{
        cmd->bits = 0;
        cmd->msg = 0;

        msg_push_bits(cmd, slave_id, 2);
        msg_push_bits(cmd, FSI_CMD_EPOLL, 3);
        msg_push_crc(cmd);
        msg_finish_cmd(cmd);
}

static void build_term_command(struct fsi_msg *cmd, uint8_t slave_id)
{
        cmd->bits = 0;
        cmd->msg = 0;

        msg_push_bits(cmd, slave_id, 2);
        msg_push_bits(cmd, FSI_CMD_TERM, 6);
        msg_push_crc(cmd);
        msg_finish_cmd(cmd);
}

static int do_copro_command(struct fsi_master_acf *master, uint32_t op)
{
        uint32_t timeout = 10000000;
        uint8_t stat;

        trace_fsi_master_acf_copro_command(master, op);

        /* Send command */
        iowrite32be(op, master->sram + CMD_STAT_REG);

        /* Ring doorbell if any */
        if (master->cvic)
                iowrite32(0x2, master->cvic + CVIC_TRIG_REG);

        /* Wait for status to indicate completion (or error) */
        do {
                if (timeout-- == 0) {
                        dev_warn(master->dev,
                                 "Timeout waiting for coprocessor completion\n");
                        return -ETIMEDOUT;
                }
                stat = ioread8(master->sram + CMD_STAT_REG);
        } while(stat < STAT_COMPLETE || stat == 0xff);

        if (stat == STAT_COMPLETE)
                return 0;
        switch(stat) {
        case STAT_ERR_INVAL_CMD:
                return -EINVAL;
        case STAT_ERR_INVAL_IRQ:
                return -EIO;
        case STAT_ERR_MTOE:
                return -ESHUTDOWN;
        }
        return -ENXIO;
}

static int clock_zeros(struct fsi_master_acf *master, int count)
{
        while (count) {
                int rc, lcnt = min(count, 255);

                rc = do_copro_command(master,
                                      CMD_IDLE_CLOCKS | (lcnt << CMD_REG_CLEN_SHIFT));
                if (rc)
                        return rc;
                count -= lcnt;
        }
        return 0;
}

static int send_request(struct fsi_master_acf *master, struct fsi_msg *cmd,
                        unsigned int resp_bits)
{
        uint32_t op;

        trace_fsi_master_acf_send_request(master, cmd, resp_bits);

        /* Store message into SRAM */
        iowrite32be((cmd->msg >> 32), master->sram + CMD_DATA);
        iowrite32be((cmd->msg & 0xffffffff), master->sram + CMD_DATA + 4);

        op = CMD_COMMAND;
        op |= cmd->bits << CMD_REG_CLEN_SHIFT;
        if (resp_bits)
                op |= resp_bits << CMD_REG_RLEN_SHIFT;

        return do_copro_command(master, op);
}

static int read_copro_response(struct fsi_master_acf *master, uint8_t size,
                               uint32_t *response, u8 *tag)
{
        uint8_t rtag = ioread8(master->sram + STAT_RTAG) & 0xf;
        uint8_t rcrc = ioread8(master->sram + STAT_RCRC) & 0xf;
        uint32_t rdata = 0;
        uint32_t crc;
        uint8_t ack;

        *tag = ack = rtag & 3;

        /* we have a whole message now; check CRC */
        crc = crc4(0, 1, 1);
        crc = crc4(crc, rtag, 4);
        if (ack == FSI_RESP_ACK && size) {
                rdata = ioread32be(master->sram + RSP_DATA);
                crc = crc4(crc, rdata, size);
                if (response)
                        *response = rdata;
        }
        crc = crc4(crc, rcrc, 4);

        trace_fsi_master_acf_copro_response(master, rtag, rcrc, rdata, crc == 0);

        if (crc) {
                /*
                 * Check if it's all 1's or all 0's, that probably means
                 * the host is off
                 */
                if ((rtag == 0xf && rcrc == 0xf) || (rtag == 0 && rcrc == 0))
                        return -ENODEV;
                dev_dbg(master->dev, "Bad response CRC !\n");
                return -EAGAIN;
        }
        return 0;
}

static int send_term(struct fsi_master_acf *master, uint8_t slave)
{
        struct fsi_msg cmd;
        uint8_t tag;
        int rc;

        build_term_command(&cmd, slave);

        rc = send_request(master, &cmd, 0);
        if (rc) {
                dev_warn(master->dev, "Error %d sending term\n", rc);
                return rc;
        }

        rc = read_copro_response(master, 0, NULL, &tag);
        if (rc < 0) {
                dev_err(master->dev,
                                "TERM failed; lost communication with slave\n");
                return -EIO;
        } else if (tag != FSI_RESP_ACK) {
                dev_err(master->dev, "TERM failed; response %d\n", tag);
                return -EIO;
        }
        return 0;
}

static void dump_ucode_trace(struct fsi_master_acf *master)
{
        char trbuf[52];
        char *p;
        int i;

        dev_dbg(master->dev,
                "CMDSTAT:%08x RTAG=%02x RCRC=%02x RDATA=%02x #INT=%08x\n",
                ioread32be(master->sram + CMD_STAT_REG),
                ioread8(master->sram + STAT_RTAG),
                ioread8(master->sram + STAT_RCRC),
                ioread32be(master->sram + RSP_DATA),
                ioread32be(master->sram + INT_CNT));

        for (i = 0; i < 512; i++) {
                uint8_t v;
                if ((i % 16) == 0)
                        p = trbuf;
                v = ioread8(master->sram + TRACEBUF + i);
                p += sprintf(p, "%02x ", v);
                if (((i % 16) == 15) || v == TR_END)
                        dev_dbg(master->dev, "%s\n", trbuf);
                if (v == TR_END)
                        break;
        }
}

static int handle_response(struct fsi_master_acf *master,
                           uint8_t slave, uint8_t size, void *data)
{
        int busy_count = 0, rc;
        int crc_err_retries = 0;
        struct fsi_msg cmd;
        uint32_t response;
        uint8_t tag;
retry:
        rc = read_copro_response(master, size, &response, &tag);

        /* Handle retries on CRC errors */
        if (rc == -EAGAIN) {
                /* Too many retries ? */
                if (crc_err_retries++ > FSI_CRC_ERR_RETRIES) {
                        /*
                         * Pass it up as a -EIO otherwise upper level will retry
                         * the whole command which isn't what we want here.
                         */
                        rc = -EIO;
                        goto bail;
                }
                trace_fsi_master_acf_crc_rsp_error(master, crc_err_retries);
                if (master->trace_enabled)
                        dump_ucode_trace(master);
                rc = clock_zeros(master, FSI_MASTER_EPOLL_CLOCKS);
                if (rc) {
                        dev_warn(master->dev,
                                 "Error %d clocking zeros for E_POLL\n", rc);
                        return rc;
                }
                build_epoll_command(&cmd, slave);
                rc = send_request(master, &cmd, size);
                if (rc) {
                        dev_warn(master->dev, "Error %d sending E_POLL\n", rc);
                        return -EIO;
                }
                goto retry;
        }
        if (rc)
                return rc;

        switch (tag) {
        case FSI_RESP_ACK:
                if (size && data) {
                        if (size == 32)
                                *(__be32 *)data = cpu_to_be32(response);
                        else if (size == 16)
                                *(__be16 *)data = cpu_to_be16(response);
                        else
                                *(u8 *)data = response;
                }
                break;
        case FSI_RESP_BUSY:
                /*
                 * Its necessary to clock slave before issuing
                 * d-poll, not indicated in the hardware protocol
                 * spec. < 20 clocks causes slave to hang, 21 ok.
                 */
                dev_dbg(master->dev, "Busy, retrying...\n");
                if (master->trace_enabled)
                        dump_ucode_trace(master);
                rc = clock_zeros(master, FSI_MASTER_DPOLL_CLOCKS);
                if (rc) {
                        dev_warn(master->dev,
                                 "Error %d clocking zeros for D_POLL\n", rc);
                        break;
                }
                if (busy_count++ < FSI_MASTER_MAX_BUSY) {
                        build_dpoll_command(&cmd, slave);
                        rc = send_request(master, &cmd, size);
                        if (rc) {
                                dev_warn(master->dev, "Error %d sending D_POLL\n", rc);
                                break;
                        }
                        goto retry;
                }
                dev_dbg(master->dev,
                        "ERR slave is stuck in busy state, issuing TERM\n");
                send_term(master, slave);
                rc = -EIO;
                break;

        case FSI_RESP_ERRA:
                dev_dbg(master->dev, "ERRA received\n");
                if (master->trace_enabled)
                        dump_ucode_trace(master);
                rc = -EIO;
                break;
        case FSI_RESP_ERRC:
                dev_dbg(master->dev, "ERRC received\n");
                if (master->trace_enabled)
                        dump_ucode_trace(master);
                rc = -EAGAIN;
                break;
        }
 bail:
        if (busy_count > 0) {
                trace_fsi_master_acf_poll_response_busy(master, busy_count);
        }

        return rc;
}

static int fsi_master_acf_xfer(struct fsi_master_acf *master, uint8_t slave,
                               struct fsi_msg *cmd, size_t resp_len, void *resp)
{
        int rc = -EAGAIN, retries = 0;

        resp_len <<= 3;
        while ((retries++) < FSI_CRC_ERR_RETRIES) {
                rc = send_request(master, cmd, resp_len);
                if (rc) {
                        if (rc != -ESHUTDOWN)
                                dev_warn(master->dev, "Error %d sending command\n", rc);
                        break;
                }
                rc = handle_response(master, slave, resp_len, resp);
                if (rc != -EAGAIN)
                        break;
                rc = -EIO;
                dev_dbg(master->dev, "ECRC retry %d\n", retries);

                /* Pace it a bit before retry */
                msleep(1);
        }

        return rc;
}

static int fsi_master_acf_read(struct fsi_master *_master, int link,
                               uint8_t id, uint32_t addr, void *val,
                               size_t size)
{
        struct fsi_master_acf *master = to_fsi_master_acf(_master);
        struct fsi_msg cmd;
        int rc;

        if (link != 0)
                return -ENODEV;

        mutex_lock(&master->lock);
        dev_dbg(master->dev, "read id %d addr %x size %zd\n", id, addr, size);
        build_ar_command(master, &cmd, id, addr, size, NULL);
        rc = fsi_master_acf_xfer(master, id, &cmd, size, val);
        last_address_update(master, id, rc == 0, addr);
        if (rc)
                dev_dbg(master->dev, "read id %d addr 0x%08x err: %d\n",
                        id, addr, rc);
        mutex_unlock(&master->lock);

        return rc;
}

static int fsi_master_acf_write(struct fsi_master *_master, int link,
                                uint8_t id, uint32_t addr, const void *val,
                                size_t size)
{
        struct fsi_master_acf *master = to_fsi_master_acf(_master);
        struct fsi_msg cmd;
        int rc;

        if (link != 0)
                return -ENODEV;

        mutex_lock(&master->lock);
        build_ar_command(master, &cmd, id, addr, size, val);
        dev_dbg(master->dev, "write id %d addr %x size %zd raw_data: %08x\n",
                id, addr, size, *(uint32_t *)val);
        rc = fsi_master_acf_xfer(master, id, &cmd, 0, NULL);
        last_address_update(master, id, rc == 0, addr);
        if (rc)
                dev_dbg(master->dev, "write id %d addr 0x%08x err: %d\n",
                        id, addr, rc);
        mutex_unlock(&master->lock);

        return rc;
}

static int fsi_master_acf_term(struct fsi_master *_master,
                               int link, uint8_t id)
{
        struct fsi_master_acf *master = to_fsi_master_acf(_master);
        struct fsi_msg cmd;
        int rc;

        if (link != 0)
                return -ENODEV;

        mutex_lock(&master->lock);
        build_term_command(&cmd, id);
        dev_dbg(master->dev, "term id %d\n", id);
        rc = fsi_master_acf_xfer(master, id, &cmd, 0, NULL);
        last_address_update(master, id, false, 0);
        mutex_unlock(&master->lock);

        return rc;
}

static int fsi_master_acf_break(struct fsi_master *_master, int link)
{
        struct fsi_master_acf *master = to_fsi_master_acf(_master);
        int rc;

        if (link != 0)
                return -ENODEV;

        mutex_lock(&master->lock);
        if (master->external_mode) {
                mutex_unlock(&master->lock);
                return -EBUSY;
        }
        dev_dbg(master->dev, "sending BREAK\n");
        rc = do_copro_command(master, CMD_BREAK);
        last_address_update(master, 0, false, 0);
        mutex_unlock(&master->lock);

        /* Wait for logic reset to take effect */
        udelay(200);

        return rc;
}

static void reset_cf(struct fsi_master_acf *master)
{
        regmap_write(master->scu, SCU_COPRO_CTRL, SCU_COPRO_RESET);
        usleep_range(20,20);
        regmap_write(master->scu, SCU_COPRO_CTRL, 0);
        usleep_range(20,20);
}

static void start_cf(struct fsi_master_acf *master)
{
        regmap_write(master->scu, SCU_COPRO_CTRL, SCU_COPRO_CLK_EN);
}

static void setup_ast2500_cf_maps(struct fsi_master_acf *master)
{
        /*
         * Note about byteswap setting: the bus is wired backwards,
         * so setting the byteswap bit actually makes the ColdFire
         * work "normally" for a BE processor, ie, put the MSB in
         * the lowest address byte.
         *
         * We thus need to set the bit for our main memory which
         * contains our program code. We create two mappings for
         * the register, one with each setting.
         *
         * Segments 2 and 3 has a "swapped" mapping (BE)
         * and 6 and 7 have a non-swapped mapping (LE) which allows
         * us to avoid byteswapping register accesses since the
         * registers are all LE.
         */

        /* Setup segment 0 to our memory region */
        regmap_write(master->scu, SCU_2500_COPRO_SEG0, master->cf_mem_addr |
                     SCU_2500_COPRO_SEG_SWAP);

        /* Segments 2 and 3 to sysregs with byteswap (for SRAM) */
        regmap_write(master->scu, SCU_2500_COPRO_SEG2, SYSREG_BASE |
                     SCU_2500_COPRO_SEG_SWAP);
        regmap_write(master->scu, SCU_2500_COPRO_SEG3, SYSREG_BASE | 0x100000 |
                     SCU_2500_COPRO_SEG_SWAP);

        /* And segment 6 and 7 to sysregs no byteswap */
        regmap_write(master->scu, SCU_2500_COPRO_SEG6, SYSREG_BASE);
        regmap_write(master->scu, SCU_2500_COPRO_SEG7, SYSREG_BASE | 0x100000);

        /* Memory cachable, regs and SRAM not cachable */
        regmap_write(master->scu, SCU_2500_COPRO_CACHE_CTL,
                     SCU_2500_COPRO_SEG0_CACHE_EN | SCU_2500_COPRO_CACHE_EN);
}

static void setup_ast2400_cf_maps(struct fsi_master_acf *master)
{
        /* Setup segment 0 to our memory region */
        regmap_write(master->scu, SCU_2400_COPRO_SEG0, master->cf_mem_addr |
                     SCU_2400_COPRO_SEG_SWAP);

        /* Segments 2 to sysregs with byteswap (for SRAM) */
        regmap_write(master->scu, SCU_2400_COPRO_SEG2, SYSREG_BASE |
                     SCU_2400_COPRO_SEG_SWAP);

        /* And segment 6 to sysregs no byteswap */
        regmap_write(master->scu, SCU_2400_COPRO_SEG6, SYSREG_BASE);

        /* Memory cachable, regs and SRAM not cachable */
        regmap_write(master->scu, SCU_2400_COPRO_CACHE_CTL,
                     SCU_2400_COPRO_SEG0_CACHE_EN | SCU_2400_COPRO_CACHE_EN);
}

static void setup_common_fw_config(struct fsi_master_acf *master,
                                   void __iomem *base)
{
        iowrite16be(master->gpio_clk_vreg, base + HDR_CLOCK_GPIO_VADDR);
        iowrite16be(master->gpio_clk_dreg, base + HDR_CLOCK_GPIO_DADDR);
        iowrite16be(master->gpio_dat_vreg, base + HDR_DATA_GPIO_VADDR);
        iowrite16be(master->gpio_dat_dreg, base + HDR_DATA_GPIO_DADDR);
        iowrite16be(master->gpio_tra_vreg, base + HDR_TRANS_GPIO_VADDR);
        iowrite16be(master->gpio_tra_dreg, base + HDR_TRANS_GPIO_DADDR);
        iowrite8(master->gpio_clk_bit, base + HDR_CLOCK_GPIO_BIT);
        iowrite8(master->gpio_dat_bit, base + HDR_DATA_GPIO_BIT);
        iowrite8(master->gpio_tra_bit, base + HDR_TRANS_GPIO_BIT);
}

static void setup_ast2500_fw_config(struct fsi_master_acf *master)
{
        void __iomem *base = master->cf_mem + HDR_OFFSET;

        setup_common_fw_config(master, base);
        iowrite32be(FW_CONTROL_USE_STOP, base + HDR_FW_CONTROL);
}

static void setup_ast2400_fw_config(struct fsi_master_acf *master)
{
        void __iomem *base = master->cf_mem + HDR_OFFSET;

        setup_common_fw_config(master, base);
        iowrite32be(FW_CONTROL_CONT_CLOCK|FW_CONTROL_DUMMY_RD, base + HDR_FW_CONTROL);
}

static int setup_gpios_for_copro(struct fsi_master_acf *master)
{

        int rc;

        /* This aren't under ColdFire control, just set them up appropriately */
        gpiod_direction_output(master->gpio_mux, 1);
        gpiod_direction_output(master->gpio_enable, 1);

        /* Those are under ColdFire control, let it configure them */
        rc = aspeed_gpio_copro_grab_gpio(master->gpio_clk, &master->gpio_clk_vreg,
                                         &master->gpio_clk_dreg, &master->gpio_clk_bit);
        if (rc) {
                dev_err(master->dev, "failed to assign clock gpio to coprocessor\n");
                return rc;
        }
        rc = aspeed_gpio_copro_grab_gpio(master->gpio_data, &master->gpio_dat_vreg,
                                         &master->gpio_dat_dreg, &master->gpio_dat_bit);
        if (rc) {
                dev_err(master->dev, "failed to assign data gpio to coprocessor\n");
                aspeed_gpio_copro_release_gpio(master->gpio_clk);
                return rc;
        }
        rc = aspeed_gpio_copro_grab_gpio(master->gpio_trans, &master->gpio_tra_vreg,
                                         &master->gpio_tra_dreg, &master->gpio_tra_bit);
        if (rc) {
                dev_err(master->dev, "failed to assign trans gpio to coprocessor\n");
                aspeed_gpio_copro_release_gpio(master->gpio_clk);
                aspeed_gpio_copro_release_gpio(master->gpio_data);
                return rc;
        }
        return 0;
}

static void release_copro_gpios(struct fsi_master_acf *master)
{
        aspeed_gpio_copro_release_gpio(master->gpio_clk);
        aspeed_gpio_copro_release_gpio(master->gpio_data);
        aspeed_gpio_copro_release_gpio(master->gpio_trans);
}

static int load_copro_firmware(struct fsi_master_acf *master)
{
        const struct firmware *fw;
        uint16_t sig = 0, wanted_sig;
        const u8 *data;
        size_t size = 0;
        int rc;

        /* Get the binary */
        rc = request_firmware(&fw, FW_FILE_NAME, master->dev);
        if (rc) {
                dev_err(
                        master->dev, "Error %d to load firmware '%s' !\n",
                        rc, FW_FILE_NAME);
                return rc;
        }

        /* Which image do we want ? (shared vs. split clock/data GPIOs) */
        if (master->gpio_clk_vreg == master->gpio_dat_vreg)
                wanted_sig = SYS_SIG_SHARED;
        else
                wanted_sig = SYS_SIG_SPLIT;
        dev_dbg(master->dev, "Looking for image sig %04x\n", wanted_sig);

        /* Try to find it */
        for (data = fw->data; data < (fw->data + fw->size);) {
                sig = be16_to_cpup((__be16 *)(data + HDR_OFFSET + HDR_SYS_SIG));
                size = be32_to_cpup((__be32 *)(data + HDR_OFFSET + HDR_FW_SIZE));
                if (sig == wanted_sig)
                        break;
                data += size;
        }
        if (sig != wanted_sig) {
                dev_err(master->dev, "Failed to locate image sig %04x in FW blob\n",
                        wanted_sig);
                rc = -ENODEV;
                goto release_fw;
        }
        if (size > master->cf_mem_size) {
                dev_err(master->dev, "FW size (%zd) bigger than memory reserve (%zd)\n",
                        fw->size, master->cf_mem_size);
                rc = -ENOMEM;
        } else {
                memcpy_toio(master->cf_mem, data, size);
        }

release_fw:
        release_firmware(fw);
        return rc;
}

static int check_firmware_image(struct fsi_master_acf *master)
{
        uint32_t fw_vers, fw_api, fw_options;

        fw_vers = ioread16be(master->cf_mem + HDR_OFFSET + HDR_FW_VERS);
        fw_api = ioread16be(master->cf_mem + HDR_OFFSET + HDR_API_VERS);
        fw_options = ioread32be(master->cf_mem + HDR_OFFSET + HDR_FW_OPTIONS);
        master->trace_enabled = !!(fw_options & FW_OPTION_TRACE_EN);

        /* Check version and signature */
        dev_info(master->dev, "ColdFire initialized, firmware v%d API v%d.%d (trace %s)\n",
                 fw_vers, fw_api >> 8, fw_api & 0xff,
                 master->trace_enabled ? "enabled" : "disabled");

        if ((fw_api >> 8) != API_VERSION_MAJ) {
                dev_err(master->dev, "Unsupported coprocessor API version !\n");
                return -ENODEV;
        }

        return 0;
}

static int copro_enable_sw_irq(struct fsi_master_acf *master)
{
        int timeout;
        uint32_t val;

        /*
         * Enable coprocessor interrupt input. I've had problems getting the
         * value to stick, so try in a loop
         */
        for (timeout = 0; timeout < 10; timeout++) {
                iowrite32(0x2, master->cvic + CVIC_EN_REG);
                val = ioread32(master->cvic + CVIC_EN_REG);
                if (val & 2)
                        break;
                msleep(1);
        }
        if (!(val & 2)) {
                dev_err(master->dev, "Failed to enable coprocessor interrupt !\n");
                return -ENODEV;
        }
        return 0;
}

static int fsi_master_acf_setup(struct fsi_master_acf *master)
{
        int timeout, rc;
        uint32_t val;

        /* Make sure the ColdFire is stopped  */
        reset_cf(master);

        /*
         * Clear SRAM. This needs to happen before we setup the GPIOs
         * as we might start trying to arbitrate as soon as that happens.
         */
        memset_io(master->sram, 0, SRAM_SIZE);

        /* Configure GPIOs */
        rc = setup_gpios_for_copro(master);
        if (rc)
                return rc;

        /* Load the firmware into the reserved memory */
        rc = load_copro_firmware(master);
        if (rc)
                return rc;

        /* Read signature and check versions */
        rc = check_firmware_image(master);
        if (rc)
                return rc;

        /* Setup coldfire memory map */
        if (master->is_ast2500) {
                setup_ast2500_cf_maps(master);
                setup_ast2500_fw_config(master);
        } else {
                setup_ast2400_cf_maps(master);
                setup_ast2400_fw_config(master);
        }

        /* Start the ColdFire */
        start_cf(master);

        /* Wait for status register to indicate command completion
         * which signals the initialization is complete
         */
        for (timeout = 0; timeout < 10; timeout++) {
                val = ioread8(master->sram + CF_STARTED);
                if (val)
                        break;
                msleep(1);
        }
        if (!val) {
                dev_err(master->dev, "Coprocessor startup timeout !\n");
                rc = -ENODEV;
                goto err;
        }

        /* Configure echo & send delay */
        iowrite8(master->t_send_delay, master->sram + SEND_DLY_REG);
        iowrite8(master->t_echo_delay, master->sram + ECHO_DLY_REG);

        /* Enable SW interrupt to copro if any */
        if (master->cvic) {
                rc = copro_enable_sw_irq(master);
                if (rc)
                        goto err;
        }
        return 0;
 err:
        /* An error occurred, don't leave the coprocessor running */
        reset_cf(master);

        /* Release the GPIOs */
        release_copro_gpios(master);

        return rc;
}


static void fsi_master_acf_terminate(struct fsi_master_acf *master)
{
        unsigned long flags;

        /*
         * A GPIO arbitration requestion could come in while this is
         * happening. To avoid problems, we disable interrupts so it
         * cannot preempt us on this CPU
         */

        local_irq_save(flags);

        /* Stop the coprocessor */
        reset_cf(master);

        /* We mark the copro not-started */
        iowrite32(0, master->sram + CF_STARTED);

        /* We mark the ARB register as having given up arbitration to
         * deal with a potential race with the arbitration request
         */
        iowrite8(ARB_ARM_ACK, master->sram + ARB_REG);

        local_irq_restore(flags);

        /* Return the GPIOs to the ARM */
        release_copro_gpios(master);
}

static void fsi_master_acf_setup_external(struct fsi_master_acf *master)
{
        /* Setup GPIOs for external FSI master (FSP box) */
        gpiod_direction_output(master->gpio_mux, 0);
        gpiod_direction_output(master->gpio_trans, 0);
        gpiod_direction_output(master->gpio_enable, 1);
        gpiod_direction_input(master->gpio_clk);
        gpiod_direction_input(master->gpio_data);
}

static int fsi_master_acf_link_enable(struct fsi_master *_master, int link,
                                      bool enable)
{
        struct fsi_master_acf *master = to_fsi_master_acf(_master);
        int rc = -EBUSY;

        if (link != 0)
                return -ENODEV;

        mutex_lock(&master->lock);
        if (!master->external_mode) {
                gpiod_set_value(master->gpio_enable, enable ? 1 : 0);
                rc = 0;
        }
        mutex_unlock(&master->lock);

        return rc;
}

static int fsi_master_acf_link_config(struct fsi_master *_master, int link,
                                      u8 t_send_delay, u8 t_echo_delay)
{
        struct fsi_master_acf *master = to_fsi_master_acf(_master);

        if (link != 0)
                return -ENODEV;

        mutex_lock(&master->lock);
        master->t_send_delay = t_send_delay;
        master->t_echo_delay = t_echo_delay;
        dev_dbg(master->dev, "Changing delays: send=%d echo=%d\n",
                t_send_delay, t_echo_delay);
        iowrite8(master->t_send_delay, master->sram + SEND_DLY_REG);
        iowrite8(master->t_echo_delay, master->sram + ECHO_DLY_REG);
        mutex_unlock(&master->lock);

        return 0;
}

static ssize_t external_mode_show(struct device *dev,
                                  struct device_attribute *attr, char *buf)
{
        struct fsi_master_acf *master = dev_get_drvdata(dev);

        return snprintf(buf, PAGE_SIZE - 1, "%u\n",
                        master->external_mode ? 1 : 0);
}

static ssize_t external_mode_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        struct fsi_master_acf *master = dev_get_drvdata(dev);
        unsigned long val;
        bool external_mode;
        int err;

        err = kstrtoul(buf, 0, &val);
        if (err)
                return err;

        external_mode = !!val;

        mutex_lock(&master->lock);

        if (external_mode == master->external_mode) {
                mutex_unlock(&master->lock);
                return count;
        }

        master->external_mode = external_mode;
        if (master->external_mode) {
                fsi_master_acf_terminate(master);
                fsi_master_acf_setup_external(master);
        } else
                fsi_master_acf_setup(master);

        mutex_unlock(&master->lock);

        fsi_master_rescan(&master->master);

        return count;
}

static DEVICE_ATTR(external_mode, 0664,
                external_mode_show, external_mode_store);

static int fsi_master_acf_gpio_request(void *data)
{
        struct fsi_master_acf *master = data;
        int timeout;
        u8 val;

        /* Note: This doesn't require holding out mutex */

        /* Write request */
        iowrite8(ARB_ARM_REQ, master->sram + ARB_REG);

        /*
         * There is a race (which does happen at boot time) when we get an
         * arbitration request as we are either about to or just starting
         * the coprocessor.
         *
         * To handle it, we first check if we are running. If not yet we
         * check whether the copro is started in the SCU.
         *
         * If it's not started, we can basically just assume we have arbitration
         * and return. Otherwise, we wait normally expecting for the arbitration
         * to eventually complete.
         */
        if (ioread32(master->sram + CF_STARTED) == 0) {
                unsigned int reg = 0;

                regmap_read(master->scu, SCU_COPRO_CTRL, &reg);
                if (!(reg & SCU_COPRO_CLK_EN))
                        return 0;
        }

        /* Ring doorbell if any */
        if (master->cvic)
                iowrite32(0x2, master->cvic + CVIC_TRIG_REG);

        for (timeout = 0; timeout < 10000; timeout++) {
                val = ioread8(master->sram + ARB_REG);
                if (val != ARB_ARM_REQ)
                        break;
                udelay(1);
        }

        /* If it failed, override anyway */
        if (val != ARB_ARM_ACK)
                dev_warn(master->dev, "GPIO request arbitration timeout\n");

        return 0;
}

static int fsi_master_acf_gpio_release(void *data)
{
        struct fsi_master_acf *master = data;

        /* Write release */
        iowrite8(0, master->sram + ARB_REG);

        /* Ring doorbell if any */
        if (master->cvic)
                iowrite32(0x2, master->cvic + CVIC_TRIG_REG);

        return 0;
}

static void fsi_master_acf_release(struct device *dev)
{
        struct fsi_master_acf *master = to_fsi_master_acf(to_fsi_master(dev));

        /* Cleanup, stop coprocessor */
        mutex_lock(&master->lock);
        fsi_master_acf_terminate(master);
        aspeed_gpio_copro_set_ops(NULL, NULL);
        mutex_unlock(&master->lock);

        /* Free resources */
        gen_pool_free(master->sram_pool, (unsigned long)master->sram, SRAM_SIZE);
        of_node_put(dev_of_node(master->dev));

        kfree(master);
}

static const struct aspeed_gpio_copro_ops fsi_master_acf_gpio_ops = {
        .request_access = fsi_master_acf_gpio_request,
        .release_access = fsi_master_acf_gpio_release,
};

static int fsi_master_acf_probe(struct platform_device *pdev)
{
        struct device_node *np, *mnode = dev_of_node(&pdev->dev);
        struct genpool_data_fixed gpdf;
        struct fsi_master_acf *master;
        struct gpio_desc *gpio;
        struct resource res;
        uint32_t cf_mem_align;
        int rc;

        master = kzalloc_obj(*master);
        if (!master)
                return -ENOMEM;

        master->dev = &pdev->dev;
        master->master.dev.parent = master->dev;
        master->last_addr = LAST_ADDR_INVALID;

        /* AST2400 vs. AST2500 */
        master->is_ast2500 = of_device_is_compatible(mnode, "aspeed,ast2500-cf-fsi-master");

        /* Grab the SCU, we'll need to access it to configure the coprocessor */
        if (master->is_ast2500)
                master->scu = syscon_regmap_lookup_by_compatible("aspeed,ast2500-scu");
        else
                master->scu = syscon_regmap_lookup_by_compatible("aspeed,ast2400-scu");
        if (IS_ERR(master->scu)) {
                dev_err(&pdev->dev, "failed to find SCU regmap\n");
                rc = PTR_ERR(master->scu);
                goto err_free;
        }

        /* Grab all the GPIOs we need */
        gpio = devm_gpiod_get(&pdev->dev, "clock", 0);
        if (IS_ERR(gpio)) {
                dev_err(&pdev->dev, "failed to get clock gpio\n");
                rc = PTR_ERR(gpio);
                goto err_free;
        }
        master->gpio_clk = gpio;

        gpio = devm_gpiod_get(&pdev->dev, "data", 0);
        if (IS_ERR(gpio)) {
                dev_err(&pdev->dev, "failed to get data gpio\n");
                rc = PTR_ERR(gpio);
                goto err_free;
        }
        master->gpio_data = gpio;

        /* Optional GPIOs */
        gpio = devm_gpiod_get_optional(&pdev->dev, "trans", 0);
        if (IS_ERR(gpio)) {
                dev_err(&pdev->dev, "failed to get trans gpio\n");
                rc = PTR_ERR(gpio);
                goto err_free;
        }
        master->gpio_trans = gpio;

        gpio = devm_gpiod_get_optional(&pdev->dev, "enable", 0);
        if (IS_ERR(gpio)) {
                dev_err(&pdev->dev, "failed to get enable gpio\n");
                rc = PTR_ERR(gpio);
                goto err_free;
        }
        master->gpio_enable = gpio;

        gpio = devm_gpiod_get_optional(&pdev->dev, "mux", 0);
        if (IS_ERR(gpio)) {
                dev_err(&pdev->dev, "failed to get mux gpio\n");
                rc = PTR_ERR(gpio);
                goto err_free;
        }
        master->gpio_mux = gpio;

        /* Grab the reserved memory region (use DMA API instead ?) */
        rc = of_reserved_mem_region_to_resource(mnode, 0, &res);
        if (rc) {
                dev_err(&pdev->dev, "Couldn't address to resource for reserved memory\n");
                rc = -ENOMEM;
                goto err_free;
        }
        master->cf_mem_size = resource_size(&res);
        master->cf_mem_addr = (uint32_t)res.start;
        cf_mem_align = master->is_ast2500 ? 0x00100000 : 0x00200000;
        if (master->cf_mem_addr & (cf_mem_align - 1)) {
                dev_err(&pdev->dev, "Reserved memory has insufficient alignment\n");
                rc = -ENOMEM;
                goto err_free;
        }
        master->cf_mem = devm_ioremap_resource(&pdev->dev, &res);
        if (IS_ERR(master->cf_mem)) {
                rc = PTR_ERR(master->cf_mem);
                goto err_free;
        }
        dev_dbg(&pdev->dev, "DRAM allocation @%x\n", master->cf_mem_addr);

        /* AST2500 has a SW interrupt to the coprocessor */
        if (master->is_ast2500) {
                /* Grab the CVIC (ColdFire interrupts controller) */
                np = of_parse_phandle(mnode, "aspeed,cvic", 0);
                if (!np) {
                        dev_err(&pdev->dev, "Didn't find CVIC\n");
                        rc = -EINVAL;
                        goto err_free;
                }
                master->cvic = devm_of_iomap(&pdev->dev, np, 0, NULL);
                if (IS_ERR(master->cvic)) {
                        of_node_put(np);
                        rc = PTR_ERR(master->cvic);
                        dev_err(&pdev->dev, "Error %d mapping CVIC\n", rc);
                        goto err_free;
                }
                rc = of_property_read_u32(np, "copro-sw-interrupts",
                                          &master->cvic_sw_irq);
                of_node_put(np);
                if (rc) {
                        dev_err(&pdev->dev, "Can't find coprocessor SW interrupt\n");
                        goto err_free;
                }
        }

        /* Grab the SRAM */
        master->sram_pool = of_gen_pool_get(dev_of_node(&pdev->dev), "aspeed,sram", 0);
        if (!master->sram_pool) {
                rc = -ENODEV;
                dev_err(&pdev->dev, "Can't find sram pool\n");
                goto err_free;
        }

        /* Current microcode only deals with fixed location in SRAM */
        gpdf.offset = 0;
        master->sram = (void __iomem *)gen_pool_alloc_algo(master->sram_pool, SRAM_SIZE,
                                                           gen_pool_fixed_alloc, &gpdf);
        if (!master->sram) {
                rc = -ENOMEM;
                dev_err(&pdev->dev, "Failed to allocate sram from pool\n");
                goto err_free;
        }
        dev_dbg(&pdev->dev, "SRAM allocation @%lx\n",
                (unsigned long)gen_pool_virt_to_phys(master->sram_pool,
                                                     (unsigned long)master->sram));

        /*
         * Hookup with the GPIO driver for arbitration of GPIO banks
         * ownership.
         */
        aspeed_gpio_copro_set_ops(&fsi_master_acf_gpio_ops, master);

        /* Default FSI command delays */
        master->t_send_delay = FSI_SEND_DELAY_CLOCKS;
        master->t_echo_delay = FSI_ECHO_DELAY_CLOCKS;
        master->master.n_links = 1;
        if (master->is_ast2500)
                master->master.flags = FSI_MASTER_FLAG_SWCLOCK;
        master->master.read = fsi_master_acf_read;
        master->master.write = fsi_master_acf_write;
        master->master.term = fsi_master_acf_term;
        master->master.send_break = fsi_master_acf_break;
        master->master.link_enable = fsi_master_acf_link_enable;
        master->master.link_config = fsi_master_acf_link_config;
        master->master.dev.of_node = of_node_get(dev_of_node(master->dev));
        master->master.dev.release = fsi_master_acf_release;
        platform_set_drvdata(pdev, master);
        mutex_init(&master->lock);

        mutex_lock(&master->lock);
        rc = fsi_master_acf_setup(master);
        mutex_unlock(&master->lock);
        if (rc)
                goto release_of_dev;

        rc = device_create_file(&pdev->dev, &dev_attr_external_mode);
        if (rc)
                goto stop_copro;

        rc = fsi_master_register(&master->master);
        if (!rc)
                return 0;

        device_remove_file(master->dev, &dev_attr_external_mode);
        put_device(&master->master.dev);
        return rc;

 stop_copro:
        fsi_master_acf_terminate(master);
 release_of_dev:
        aspeed_gpio_copro_set_ops(NULL, NULL);
        gen_pool_free(master->sram_pool, (unsigned long)master->sram, SRAM_SIZE);
        of_node_put(dev_of_node(master->dev));
 err_free:
        kfree(master);
        return rc;
}


static void fsi_master_acf_remove(struct platform_device *pdev)
{
        struct fsi_master_acf *master = platform_get_drvdata(pdev);

        device_remove_file(master->dev, &dev_attr_external_mode);

        fsi_master_unregister(&master->master);
}

static const struct of_device_id fsi_master_acf_match[] = {
        { .compatible = "aspeed,ast2400-cf-fsi-master" },
        { .compatible = "aspeed,ast2500-cf-fsi-master" },
        { },
};
MODULE_DEVICE_TABLE(of, fsi_master_acf_match);

static struct platform_driver fsi_master_acf = {
        .driver = {
                .name           = "fsi-master-acf",
                .of_match_table = fsi_master_acf_match,
        },
        .probe  = fsi_master_acf_probe,
        .remove = fsi_master_acf_remove,
};

module_platform_driver(fsi_master_acf);
MODULE_DESCRIPTION("A FSI master based on Aspeed ColdFire coprocessor");
MODULE_LICENSE("GPL");
MODULE_FIRMWARE(FW_FILE_NAME);