root/drivers/tty/serial/pch_uart.c
// SPDX-License-Identifier: GPL-2.0
/*
 *Copyright (C) 2011 LAPIS Semiconductor Co., Ltd.
 */
#include <linux/kernel.h>
#include <linux/serial.h>
#include <linux/serial_reg.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/console.h>
#include <linux/serial_core.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/dmi.h>
#include <linux/nmi.h>
#include <linux/delay.h>
#include <linux/of.h>

#include <linux/debugfs.h>
#include <linux/dmaengine.h>
#include <linux/pch_dma.h>

enum {
        PCH_UART_HANDLED_RX_INT_SHIFT,
        PCH_UART_HANDLED_TX_INT_SHIFT,
        PCH_UART_HANDLED_RX_ERR_INT_SHIFT,
        PCH_UART_HANDLED_RX_TRG_INT_SHIFT,
        PCH_UART_HANDLED_MS_INT_SHIFT,
        PCH_UART_HANDLED_LS_INT_SHIFT,
};

#define PCH_UART_DRIVER_DEVICE "ttyPCH"

/* Set the max number of UART port
 * Intel EG20T PCH: 4 port
 * LAPIS Semiconductor ML7213 IOH: 3 port
 * LAPIS Semiconductor ML7223 IOH: 2 port
*/
#define PCH_UART_NR     4

#define PCH_UART_HANDLED_RX_INT (1<<((PCH_UART_HANDLED_RX_INT_SHIFT)<<1))
#define PCH_UART_HANDLED_TX_INT (1<<((PCH_UART_HANDLED_TX_INT_SHIFT)<<1))
#define PCH_UART_HANDLED_RX_ERR_INT     (1<<((\
                                        PCH_UART_HANDLED_RX_ERR_INT_SHIFT)<<1))
#define PCH_UART_HANDLED_RX_TRG_INT     (1<<((\
                                        PCH_UART_HANDLED_RX_TRG_INT_SHIFT)<<1))
#define PCH_UART_HANDLED_MS_INT (1<<((PCH_UART_HANDLED_MS_INT_SHIFT)<<1))

#define PCH_UART_HANDLED_LS_INT (1<<((PCH_UART_HANDLED_LS_INT_SHIFT)<<1))

#define PCH_UART_RBR            0x00
#define PCH_UART_THR            0x00

#define PCH_UART_IER_MASK       (PCH_UART_IER_ERBFI|PCH_UART_IER_ETBEI|\
                                PCH_UART_IER_ELSI|PCH_UART_IER_EDSSI)
#define PCH_UART_IER_ERBFI      0x00000001
#define PCH_UART_IER_ETBEI      0x00000002
#define PCH_UART_IER_ELSI       0x00000004
#define PCH_UART_IER_EDSSI      0x00000008

#define PCH_UART_IIR_IP                 0x00000001
#define PCH_UART_IIR_IID                0x00000006
#define PCH_UART_IIR_MSI                0x00000000
#define PCH_UART_IIR_TRI                0x00000002
#define PCH_UART_IIR_RRI                0x00000004
#define PCH_UART_IIR_REI                0x00000006
#define PCH_UART_IIR_TOI                0x00000008
#define PCH_UART_IIR_FIFO256            0x00000020
#define PCH_UART_IIR_FIFO64             PCH_UART_IIR_FIFO256
#define PCH_UART_IIR_FE                 0x000000C0

#define PCH_UART_FCR_FIFOE              0x00000001
#define PCH_UART_FCR_RFR                0x00000002
#define PCH_UART_FCR_TFR                0x00000004
#define PCH_UART_FCR_DMS                0x00000008
#define PCH_UART_FCR_FIFO256            0x00000020
#define PCH_UART_FCR_RFTL               0x000000C0

#define PCH_UART_FCR_RFTL1              0x00000000
#define PCH_UART_FCR_RFTL64             0x00000040
#define PCH_UART_FCR_RFTL128            0x00000080
#define PCH_UART_FCR_RFTL224            0x000000C0
#define PCH_UART_FCR_RFTL16             PCH_UART_FCR_RFTL64
#define PCH_UART_FCR_RFTL32             PCH_UART_FCR_RFTL128
#define PCH_UART_FCR_RFTL56             PCH_UART_FCR_RFTL224
#define PCH_UART_FCR_RFTL4              PCH_UART_FCR_RFTL64
#define PCH_UART_FCR_RFTL8              PCH_UART_FCR_RFTL128
#define PCH_UART_FCR_RFTL14             PCH_UART_FCR_RFTL224
#define PCH_UART_FCR_RFTL_SHIFT         6

#define PCH_UART_LCR_WLS        0x00000003
#define PCH_UART_LCR_STB        0x00000004
#define PCH_UART_LCR_PEN        0x00000008
#define PCH_UART_LCR_EPS        0x00000010
#define PCH_UART_LCR_SP         0x00000020
#define PCH_UART_LCR_SB         0x00000040
#define PCH_UART_LCR_DLAB       0x00000080
#define PCH_UART_LCR_NP         0x00000000
#define PCH_UART_LCR_OP         PCH_UART_LCR_PEN
#define PCH_UART_LCR_EP         (PCH_UART_LCR_PEN | PCH_UART_LCR_EPS)
#define PCH_UART_LCR_1P         (PCH_UART_LCR_PEN | PCH_UART_LCR_SP)
#define PCH_UART_LCR_0P         (PCH_UART_LCR_PEN | PCH_UART_LCR_EPS |\
                                PCH_UART_LCR_SP)

#define PCH_UART_LCR_5BIT       0x00000000
#define PCH_UART_LCR_6BIT       0x00000001
#define PCH_UART_LCR_7BIT       0x00000002
#define PCH_UART_LCR_8BIT       0x00000003

#define PCH_UART_MCR_DTR        0x00000001
#define PCH_UART_MCR_RTS        0x00000002
#define PCH_UART_MCR_OUT        0x0000000C
#define PCH_UART_MCR_LOOP       0x00000010
#define PCH_UART_MCR_AFE        0x00000020

#define PCH_UART_LSR_DR         0x00000001
#define PCH_UART_LSR_ERR        (1<<7)

#define PCH_UART_MSR_DCTS       0x00000001
#define PCH_UART_MSR_DDSR       0x00000002
#define PCH_UART_MSR_TERI       0x00000004
#define PCH_UART_MSR_DDCD       0x00000008
#define PCH_UART_MSR_CTS        0x00000010
#define PCH_UART_MSR_DSR        0x00000020
#define PCH_UART_MSR_RI         0x00000040
#define PCH_UART_MSR_DCD        0x00000080
#define PCH_UART_MSR_DELTA      (PCH_UART_MSR_DCTS | PCH_UART_MSR_DDSR |\
                                PCH_UART_MSR_TERI | PCH_UART_MSR_DDCD)

#define PCH_UART_DLL            0x00
#define PCH_UART_DLM            0x01

#define PCH_UART_BRCSR          0x0E

#define PCH_UART_IID_RLS        (PCH_UART_IIR_REI)
#define PCH_UART_IID_RDR        (PCH_UART_IIR_RRI)
#define PCH_UART_IID_RDR_TO     (PCH_UART_IIR_RRI | PCH_UART_IIR_TOI)
#define PCH_UART_IID_THRE       (PCH_UART_IIR_TRI)
#define PCH_UART_IID_MS         (PCH_UART_IIR_MSI)

#define PCH_UART_HAL_PARITY_NONE        (PCH_UART_LCR_NP)
#define PCH_UART_HAL_PARITY_ODD         (PCH_UART_LCR_OP)
#define PCH_UART_HAL_PARITY_EVEN        (PCH_UART_LCR_EP)
#define PCH_UART_HAL_PARITY_FIX1        (PCH_UART_LCR_1P)
#define PCH_UART_HAL_PARITY_FIX0        (PCH_UART_LCR_0P)
#define PCH_UART_HAL_5BIT               (PCH_UART_LCR_5BIT)
#define PCH_UART_HAL_6BIT               (PCH_UART_LCR_6BIT)
#define PCH_UART_HAL_7BIT               (PCH_UART_LCR_7BIT)
#define PCH_UART_HAL_8BIT               (PCH_UART_LCR_8BIT)
#define PCH_UART_HAL_STB1               0
#define PCH_UART_HAL_STB2               (PCH_UART_LCR_STB)

#define PCH_UART_HAL_CLR_TX_FIFO        (PCH_UART_FCR_TFR)
#define PCH_UART_HAL_CLR_RX_FIFO        (PCH_UART_FCR_RFR)
#define PCH_UART_HAL_CLR_ALL_FIFO       (PCH_UART_HAL_CLR_TX_FIFO | \
                                        PCH_UART_HAL_CLR_RX_FIFO)

#define PCH_UART_HAL_DMA_MODE0          0
#define PCH_UART_HAL_FIFO_DIS           0
#define PCH_UART_HAL_FIFO16             (PCH_UART_FCR_FIFOE)
#define PCH_UART_HAL_FIFO256            (PCH_UART_FCR_FIFOE | \
                                        PCH_UART_FCR_FIFO256)
#define PCH_UART_HAL_FIFO64             (PCH_UART_HAL_FIFO256)
#define PCH_UART_HAL_TRIGGER1           (PCH_UART_FCR_RFTL1)
#define PCH_UART_HAL_TRIGGER64          (PCH_UART_FCR_RFTL64)
#define PCH_UART_HAL_TRIGGER128         (PCH_UART_FCR_RFTL128)
#define PCH_UART_HAL_TRIGGER224         (PCH_UART_FCR_RFTL224)
#define PCH_UART_HAL_TRIGGER16          (PCH_UART_FCR_RFTL16)
#define PCH_UART_HAL_TRIGGER32          (PCH_UART_FCR_RFTL32)
#define PCH_UART_HAL_TRIGGER56          (PCH_UART_FCR_RFTL56)
#define PCH_UART_HAL_TRIGGER4           (PCH_UART_FCR_RFTL4)
#define PCH_UART_HAL_TRIGGER8           (PCH_UART_FCR_RFTL8)
#define PCH_UART_HAL_TRIGGER14          (PCH_UART_FCR_RFTL14)
#define PCH_UART_HAL_TRIGGER_L          (PCH_UART_FCR_RFTL64)
#define PCH_UART_HAL_TRIGGER_M          (PCH_UART_FCR_RFTL128)
#define PCH_UART_HAL_TRIGGER_H          (PCH_UART_FCR_RFTL224)

#define PCH_UART_HAL_RX_INT             (PCH_UART_IER_ERBFI)
#define PCH_UART_HAL_TX_INT             (PCH_UART_IER_ETBEI)
#define PCH_UART_HAL_RX_ERR_INT         (PCH_UART_IER_ELSI)
#define PCH_UART_HAL_MS_INT             (PCH_UART_IER_EDSSI)
#define PCH_UART_HAL_ALL_INT            (PCH_UART_IER_MASK)

#define PCH_UART_HAL_DTR                (PCH_UART_MCR_DTR)
#define PCH_UART_HAL_RTS                (PCH_UART_MCR_RTS)
#define PCH_UART_HAL_OUT                (PCH_UART_MCR_OUT)
#define PCH_UART_HAL_LOOP               (PCH_UART_MCR_LOOP)
#define PCH_UART_HAL_AFE                (PCH_UART_MCR_AFE)

#define DEFAULT_UARTCLK   1843200 /*   1.8432 MHz */
#define CMITC_UARTCLK   192000000 /* 192.0000 MHz */
#define FRI2_64_UARTCLK  64000000 /*  64.0000 MHz */
#define FRI2_48_UARTCLK  48000000 /*  48.0000 MHz */
#define NTC1_UARTCLK     64000000 /*  64.0000 MHz */
#define MINNOW_UARTCLK   50000000 /*  50.0000 MHz */

struct pch_uart_buffer {
        unsigned char *buf;
        int size;
};

struct eg20t_port {
        struct uart_port port;
        int port_type;
        void __iomem *membase;
        resource_size_t mapbase;
        unsigned int iobase;
        struct pci_dev *pdev;
        int fifo_size;
        unsigned int uartclk;
        int start_tx;
        int start_rx;
        int tx_empty;
        int trigger;
        int trigger_level;
        struct pch_uart_buffer rxbuf;
        unsigned int dmsr;
        unsigned int fcr;
        unsigned int mcr;
        unsigned int use_dma;
        struct dma_async_tx_descriptor  *desc_tx;
        struct dma_async_tx_descriptor  *desc_rx;
        struct pch_dma_slave            param_tx;
        struct pch_dma_slave            param_rx;
        struct dma_chan                 *chan_tx;
        struct dma_chan                 *chan_rx;
        struct scatterlist              *sg_tx_p;
        int                             nent;
        int                             orig_nent;
        struct scatterlist              sg_rx;
        int                             tx_dma_use;
        void                            *rx_buf_virt;
        dma_addr_t                      rx_buf_dma;

#define IRQ_NAME_SIZE 17
        char                            irq_name[IRQ_NAME_SIZE];
};

/**
 * struct pch_uart_driver_data - private data structure for UART-DMA
 * @port_type:                  The type of UART port
 * @line_no:                    UART port line number (0, 1, 2...)
 */
struct pch_uart_driver_data {
        int port_type;
        int line_no;
};

enum pch_uart_num_t {
        pch_et20t_uart0 = 0,
        pch_et20t_uart1,
        pch_et20t_uart2,
        pch_et20t_uart3,
        pch_ml7213_uart0,
        pch_ml7213_uart1,
        pch_ml7213_uart2,
        pch_ml7223_uart0,
        pch_ml7223_uart1,
        pch_ml7831_uart0,
        pch_ml7831_uart1,
};

static struct pch_uart_driver_data drv_dat[] = {
        [pch_et20t_uart0] = {PORT_PCH_8LINE, 0},
        [pch_et20t_uart1] = {PORT_PCH_2LINE, 1},
        [pch_et20t_uart2] = {PORT_PCH_2LINE, 2},
        [pch_et20t_uart3] = {PORT_PCH_2LINE, 3},
        [pch_ml7213_uart0] = {PORT_PCH_8LINE, 0},
        [pch_ml7213_uart1] = {PORT_PCH_2LINE, 1},
        [pch_ml7213_uart2] = {PORT_PCH_2LINE, 2},
        [pch_ml7223_uart0] = {PORT_PCH_8LINE, 0},
        [pch_ml7223_uart1] = {PORT_PCH_2LINE, 1},
        [pch_ml7831_uart0] = {PORT_PCH_8LINE, 0},
        [pch_ml7831_uart1] = {PORT_PCH_2LINE, 1},
};

#ifdef CONFIG_SERIAL_PCH_UART_CONSOLE
static struct eg20t_port *pch_uart_ports[PCH_UART_NR];
#endif
static unsigned int default_baud = 9600;
static unsigned int user_uartclk = 0;
static const int trigger_level_256[4] = { 1, 64, 128, 224 };
static const int trigger_level_64[4] = { 1, 16, 32, 56 };
static const int trigger_level_16[4] = { 1, 4, 8, 14 };
static const int trigger_level_1[4] = { 1, 1, 1, 1 };

#define PCH_REGS_BUFSIZE        1024


static ssize_t port_show_regs(struct file *file, char __user *user_buf,
                                size_t count, loff_t *ppos)
{
        struct eg20t_port *priv = file->private_data;
        char *buf;
        u32 len = 0;
        ssize_t ret;
        unsigned char lcr;

        buf = kzalloc(PCH_REGS_BUFSIZE, GFP_KERNEL);
        if (!buf)
                return 0;

        len += scnprintf(buf + len, PCH_REGS_BUFSIZE - len,
                        "PCH EG20T port[%d] regs:\n", priv->port.line);

        len += scnprintf(buf + len, PCH_REGS_BUFSIZE - len,
                        "=================================\n");
        len += scnprintf(buf + len, PCH_REGS_BUFSIZE - len,
                        "IER: \t0x%02x\n", ioread8(priv->membase + UART_IER));
        len += scnprintf(buf + len, PCH_REGS_BUFSIZE - len,
                        "IIR: \t0x%02x\n", ioread8(priv->membase + UART_IIR));
        len += scnprintf(buf + len, PCH_REGS_BUFSIZE - len,
                        "LCR: \t0x%02x\n", ioread8(priv->membase + UART_LCR));
        len += scnprintf(buf + len, PCH_REGS_BUFSIZE - len,
                        "MCR: \t0x%02x\n", ioread8(priv->membase + UART_MCR));
        len += scnprintf(buf + len, PCH_REGS_BUFSIZE - len,
                        "LSR: \t0x%02x\n", ioread8(priv->membase + UART_LSR));
        len += scnprintf(buf + len, PCH_REGS_BUFSIZE - len,
                        "MSR: \t0x%02x\n", ioread8(priv->membase + UART_MSR));
        len += scnprintf(buf + len, PCH_REGS_BUFSIZE - len,
                        "BRCSR: \t0x%02x\n",
                        ioread8(priv->membase + PCH_UART_BRCSR));

        lcr = ioread8(priv->membase + UART_LCR);
        iowrite8(PCH_UART_LCR_DLAB, priv->membase + UART_LCR);
        len += scnprintf(buf + len, PCH_REGS_BUFSIZE - len,
                        "DLL: \t0x%02x\n", ioread8(priv->membase + UART_DLL));
        len += scnprintf(buf + len, PCH_REGS_BUFSIZE - len,
                        "DLM: \t0x%02x\n", ioread8(priv->membase + UART_DLM));
        iowrite8(lcr, priv->membase + UART_LCR);

        if (len > PCH_REGS_BUFSIZE)
                len = PCH_REGS_BUFSIZE;

        ret =  simple_read_from_buffer(user_buf, count, ppos, buf, len);
        kfree(buf);
        return ret;
}

static const struct file_operations port_regs_ops = {
        .owner          = THIS_MODULE,
        .open           = simple_open,
        .read           = port_show_regs,
        .llseek         = default_llseek,
};

static const struct dmi_system_id pch_uart_dmi_table[] = {
        {
                .ident = "CM-iTC",
                {
                        DMI_MATCH(DMI_BOARD_NAME, "CM-iTC"),
                },
                (void *)CMITC_UARTCLK,
        },
        {
                .ident = "FRI2",
                {
                        DMI_MATCH(DMI_BIOS_VERSION, "FRI2"),
                },
                (void *)FRI2_64_UARTCLK,
        },
        {
                .ident = "Fish River Island II",
                {
                        DMI_MATCH(DMI_PRODUCT_NAME, "Fish River Island II"),
                },
                (void *)FRI2_48_UARTCLK,
        },
        {
                .ident = "COMe-mTT",
                {
                        DMI_MATCH(DMI_BOARD_NAME, "COMe-mTT"),
                },
                (void *)NTC1_UARTCLK,
        },
        {
                .ident = "nanoETXexpress-TT",
                {
                        DMI_MATCH(DMI_BOARD_NAME, "nanoETXexpress-TT"),
                },
                (void *)NTC1_UARTCLK,
        },
        {
                .ident = "MinnowBoard",
                {
                        DMI_MATCH(DMI_BOARD_NAME, "MinnowBoard"),
                },
                (void *)MINNOW_UARTCLK,
        },
        { }
};

/* Return UART clock, checking for board specific clocks. */
static unsigned int pch_uart_get_uartclk(void)
{
        const struct dmi_system_id *d;

        if (user_uartclk)
                return user_uartclk;

        d = dmi_first_match(pch_uart_dmi_table);
        if (d)
                return (unsigned long)d->driver_data;

        return DEFAULT_UARTCLK;
}

static void pch_uart_hal_enable_interrupt(struct eg20t_port *priv,
                                          unsigned int flag)
{
        u8 ier = ioread8(priv->membase + UART_IER);
        ier |= flag & PCH_UART_IER_MASK;
        iowrite8(ier, priv->membase + UART_IER);
}

static void pch_uart_hal_disable_interrupt(struct eg20t_port *priv,
                                           unsigned int flag)
{
        u8 ier = ioread8(priv->membase + UART_IER);
        ier &= ~(flag & PCH_UART_IER_MASK);
        iowrite8(ier, priv->membase + UART_IER);
}

static int pch_uart_hal_set_line(struct eg20t_port *priv, unsigned int baud,
                                 unsigned int parity, unsigned int bits,
                                 unsigned int stb)
{
        unsigned int dll, dlm, lcr;
        int div;

        div = DIV_ROUND_CLOSEST(priv->uartclk / 16, baud);
        if (div < 0 || USHRT_MAX <= div) {
                dev_err(priv->port.dev, "Invalid Baud(div=0x%x)\n", div);
                return -EINVAL;
        }

        dll = (unsigned int)div & 0x00FFU;
        dlm = ((unsigned int)div >> 8) & 0x00FFU;

        if (parity & ~(PCH_UART_LCR_PEN | PCH_UART_LCR_EPS | PCH_UART_LCR_SP)) {
                dev_err(priv->port.dev, "Invalid parity(0x%x)\n", parity);
                return -EINVAL;
        }

        if (bits & ~PCH_UART_LCR_WLS) {
                dev_err(priv->port.dev, "Invalid bits(0x%x)\n", bits);
                return -EINVAL;
        }

        if (stb & ~PCH_UART_LCR_STB) {
                dev_err(priv->port.dev, "Invalid STB(0x%x)\n", stb);
                return -EINVAL;
        }

        lcr = parity;
        lcr |= bits;
        lcr |= stb;

        dev_dbg(priv->port.dev, "%s:baud = %u, div = %04x, lcr = %02x (%lu)\n",
                 __func__, baud, div, lcr, jiffies);
        iowrite8(PCH_UART_LCR_DLAB, priv->membase + UART_LCR);
        iowrite8(dll, priv->membase + PCH_UART_DLL);
        iowrite8(dlm, priv->membase + PCH_UART_DLM);
        iowrite8(lcr, priv->membase + UART_LCR);

        return 0;
}

static int pch_uart_hal_fifo_reset(struct eg20t_port *priv,
                                    unsigned int flag)
{
        if (flag & ~(PCH_UART_FCR_TFR | PCH_UART_FCR_RFR)) {
                dev_err(priv->port.dev, "%s:Invalid flag(0x%x)\n",
                        __func__, flag);
                return -EINVAL;
        }

        iowrite8(PCH_UART_FCR_FIFOE | priv->fcr, priv->membase + UART_FCR);
        iowrite8(PCH_UART_FCR_FIFOE | priv->fcr | flag,
                 priv->membase + UART_FCR);
        iowrite8(priv->fcr, priv->membase + UART_FCR);

        return 0;
}

static int pch_uart_hal_set_fifo(struct eg20t_port *priv,
                                 unsigned int dmamode,
                                 unsigned int fifo_size, unsigned int trigger)
{
        u8 fcr;

        if (dmamode & ~PCH_UART_FCR_DMS) {
                dev_err(priv->port.dev, "%s:Invalid DMA Mode(0x%x)\n",
                        __func__, dmamode);
                return -EINVAL;
        }

        if (fifo_size & ~(PCH_UART_FCR_FIFOE | PCH_UART_FCR_FIFO256)) {
                dev_err(priv->port.dev, "%s:Invalid FIFO SIZE(0x%x)\n",
                        __func__, fifo_size);
                return -EINVAL;
        }

        if (trigger & ~PCH_UART_FCR_RFTL) {
                dev_err(priv->port.dev, "%s:Invalid TRIGGER(0x%x)\n",
                        __func__, trigger);
                return -EINVAL;
        }

        switch (priv->fifo_size) {
        case 256:
                priv->trigger_level =
                    trigger_level_256[trigger >> PCH_UART_FCR_RFTL_SHIFT];
                break;
        case 64:
                priv->trigger_level =
                    trigger_level_64[trigger >> PCH_UART_FCR_RFTL_SHIFT];
                break;
        case 16:
                priv->trigger_level =
                    trigger_level_16[trigger >> PCH_UART_FCR_RFTL_SHIFT];
                break;
        default:
                priv->trigger_level =
                    trigger_level_1[trigger >> PCH_UART_FCR_RFTL_SHIFT];
                break;
        }
        fcr =
            dmamode | fifo_size | trigger | PCH_UART_FCR_RFR | PCH_UART_FCR_TFR;
        iowrite8(PCH_UART_FCR_FIFOE, priv->membase + UART_FCR);
        iowrite8(PCH_UART_FCR_FIFOE | PCH_UART_FCR_RFR | PCH_UART_FCR_TFR,
                 priv->membase + UART_FCR);
        iowrite8(fcr, priv->membase + UART_FCR);
        priv->fcr = fcr;

        return 0;
}

static u8 pch_uart_hal_get_modem(struct eg20t_port *priv)
{
        unsigned int msr = ioread8(priv->membase + UART_MSR);
        priv->dmsr = msr & PCH_UART_MSR_DELTA;
        return (u8)msr;
}

static int pch_uart_hal_read(struct eg20t_port *priv, unsigned char *buf,
                             int rx_size)
{
        int i;
        u8 rbr, lsr;
        struct uart_port *port = &priv->port;

        lsr = ioread8(priv->membase + UART_LSR);
        for (i = 0, lsr = ioread8(priv->membase + UART_LSR);
             i < rx_size && lsr & (UART_LSR_DR | UART_LSR_BI);
             lsr = ioread8(priv->membase + UART_LSR)) {
                rbr = ioread8(priv->membase + PCH_UART_RBR);

                if (lsr & UART_LSR_BI) {
                        port->icount.brk++;
                        if (uart_handle_break(port))
                                continue;
                }
                if (uart_prepare_sysrq_char(port, rbr))
                        continue;

                buf[i++] = rbr;
        }
        return i;
}

static unsigned char pch_uart_hal_get_iid(struct eg20t_port *priv)
{
        return ioread8(priv->membase + UART_IIR) &\
                      (PCH_UART_IIR_IID | PCH_UART_IIR_TOI | PCH_UART_IIR_IP);
}

static u8 pch_uart_hal_get_line_status(struct eg20t_port *priv)
{
        return ioread8(priv->membase + UART_LSR);
}

static void pch_uart_hal_set_break(struct eg20t_port *priv, int on)
{
        unsigned int lcr;

        lcr = ioread8(priv->membase + UART_LCR);
        if (on)
                lcr |= PCH_UART_LCR_SB;
        else
                lcr &= ~PCH_UART_LCR_SB;

        iowrite8(lcr, priv->membase + UART_LCR);
}

static void push_rx(struct eg20t_port *priv, const unsigned char *buf,
                    int size)
{
        struct uart_port *port = &priv->port;
        struct tty_port *tport = &port->state->port;

        tty_insert_flip_string(tport, buf, size);
        tty_flip_buffer_push(tport);
}

static int dma_push_rx(struct eg20t_port *priv, int size)
{
        int room;
        struct uart_port *port = &priv->port;
        struct tty_port *tport = &port->state->port;

        room = tty_buffer_request_room(tport, size);

        if (room < size)
                dev_warn(port->dev, "Rx overrun: dropping %u bytes\n",
                         size - room);
        if (!room)
                return 0;

        tty_insert_flip_string(tport, sg_virt(&priv->sg_rx), size);

        port->icount.rx += room;

        return room;
}

static void pch_free_dma(struct uart_port *port)
{
        struct eg20t_port *priv;
        priv = container_of(port, struct eg20t_port, port);

        if (priv->chan_tx) {
                dma_release_channel(priv->chan_tx);
                priv->chan_tx = NULL;
        }
        if (priv->chan_rx) {
                dma_release_channel(priv->chan_rx);
                priv->chan_rx = NULL;
        }

        if (priv->rx_buf_dma) {
                dma_free_coherent(port->dev, port->fifosize, priv->rx_buf_virt,
                                  priv->rx_buf_dma);
                priv->rx_buf_virt = NULL;
                priv->rx_buf_dma = 0;
        }

        return;
}

static bool filter(struct dma_chan *chan, void *slave)
{
        struct pch_dma_slave *param = slave;

        if ((chan->chan_id == param->chan_id) && (param->dma_dev ==
                                                  chan->device->dev)) {
                chan->private = param;
                return true;
        } else {
                return false;
        }
}

static void pch_request_dma(struct uart_port *port)
{
        dma_cap_mask_t mask;
        struct dma_chan *chan;
        struct pci_dev *dma_dev;
        struct pch_dma_slave *param;
        struct eg20t_port *priv =
                                container_of(port, struct eg20t_port, port);
        dma_cap_zero(mask);
        dma_cap_set(DMA_SLAVE, mask);

        /* Get DMA's dev information */
        dma_dev = pci_get_slot(priv->pdev->bus,
                        PCI_DEVFN(PCI_SLOT(priv->pdev->devfn), 0));

        /* Set Tx DMA */
        param = &priv->param_tx;
        param->dma_dev = &dma_dev->dev;
        param->chan_id = priv->port.line * 2; /* Tx = 0, 2, 4, ... */

        param->tx_reg = port->mapbase + UART_TX;
        chan = dma_request_channel(mask, filter, param);
        if (!chan) {
                dev_err(priv->port.dev, "%s:dma_request_channel FAILS(Tx)\n",
                        __func__);
                pci_dev_put(dma_dev);
                return;
        }
        priv->chan_tx = chan;

        /* Set Rx DMA */
        param = &priv->param_rx;
        param->dma_dev = &dma_dev->dev;
        param->chan_id = priv->port.line * 2 + 1; /* Rx = Tx + 1 */

        param->rx_reg = port->mapbase + UART_RX;
        chan = dma_request_channel(mask, filter, param);
        if (!chan) {
                dev_err(priv->port.dev, "%s:dma_request_channel FAILS(Rx)\n",
                        __func__);
                dma_release_channel(priv->chan_tx);
                priv->chan_tx = NULL;
                pci_dev_put(dma_dev);
                return;
        }

        /* Get Consistent memory for DMA */
        priv->rx_buf_virt = dma_alloc_coherent(port->dev, port->fifosize,
                                    &priv->rx_buf_dma, GFP_KERNEL);
        priv->chan_rx = chan;

        pci_dev_put(dma_dev);
}

static void pch_dma_rx_complete(void *arg)
{
        struct eg20t_port *priv = arg;
        struct uart_port *port = &priv->port;
        int count;

        dma_sync_sg_for_cpu(port->dev, &priv->sg_rx, 1, DMA_FROM_DEVICE);
        count = dma_push_rx(priv, priv->trigger_level);
        if (count)
                tty_flip_buffer_push(&port->state->port);
        async_tx_ack(priv->desc_rx);
        pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_RX_INT |
                                            PCH_UART_HAL_RX_ERR_INT);
}

static void pch_dma_tx_complete(void *arg)
{
        struct eg20t_port *priv = arg;
        struct uart_port *port = &priv->port;
        struct scatterlist *sg = priv->sg_tx_p;
        int i;

        for (i = 0; i < priv->nent; i++, sg++)
                uart_xmit_advance(port, sg_dma_len(sg));

        async_tx_ack(priv->desc_tx);
        dma_unmap_sg(port->dev, priv->sg_tx_p, priv->orig_nent, DMA_TO_DEVICE);
        priv->tx_dma_use = 0;
        priv->nent = 0;
        priv->orig_nent = 0;
        kfree(priv->sg_tx_p);
        pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_TX_INT);
}

static int handle_rx_to(struct eg20t_port *priv)
{
        struct pch_uart_buffer *buf;
        int rx_size;

        if (!priv->start_rx) {
                pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_RX_INT |
                                                     PCH_UART_HAL_RX_ERR_INT);
                return 0;
        }
        buf = &priv->rxbuf;
        do {
                rx_size = pch_uart_hal_read(priv, buf->buf, buf->size);
                push_rx(priv, buf->buf, rx_size);
        } while (rx_size == buf->size);

        return PCH_UART_HANDLED_RX_INT;
}

static int dma_handle_rx(struct eg20t_port *priv)
{
        struct uart_port *port = &priv->port;
        struct dma_async_tx_descriptor *desc;
        struct scatterlist *sg;

        priv = container_of(port, struct eg20t_port, port);
        sg = &priv->sg_rx;

        sg_init_table(&priv->sg_rx, 1); /* Initialize SG table */

        sg_dma_len(sg) = priv->trigger_level;

        sg_set_page(&priv->sg_rx, virt_to_page(priv->rx_buf_virt),
                     sg_dma_len(sg), offset_in_page(priv->rx_buf_virt));

        sg_dma_address(sg) = priv->rx_buf_dma;

        desc = dmaengine_prep_slave_sg(priv->chan_rx,
                        sg, 1, DMA_DEV_TO_MEM,
                        DMA_PREP_INTERRUPT | DMA_CTRL_ACK);

        if (!desc)
                return 0;

        priv->desc_rx = desc;
        desc->callback = pch_dma_rx_complete;
        desc->callback_param = priv;
        desc->tx_submit(desc);
        dma_async_issue_pending(priv->chan_rx);

        return PCH_UART_HANDLED_RX_INT;
}

static unsigned int handle_tx(struct eg20t_port *priv)
{
        struct uart_port *port = &priv->port;
        unsigned char ch;
        int fifo_size;
        int tx_empty;

        if (!priv->start_tx) {
                dev_info(priv->port.dev, "%s:Tx isn't started. (%lu)\n",
                        __func__, jiffies);
                pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_TX_INT);
                priv->tx_empty = 1;
                return 0;
        }

        fifo_size = max(priv->fifo_size, 1);
        tx_empty = 1;
        if (port->x_char) {
                iowrite8(port->x_char, priv->membase + PCH_UART_THR);
                port->icount.tx++;
                port->x_char = 0;
                tx_empty = 0;
                fifo_size--;
        }

        while (!uart_tx_stopped(port) && fifo_size &&
                        uart_fifo_get(port, &ch)) {
                iowrite8(ch, priv->membase + PCH_UART_THR);
                fifo_size--;
                tx_empty = 0;
        }

        priv->tx_empty = tx_empty;

        if (tx_empty) {
                pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_TX_INT);
                uart_write_wakeup(port);
        }

        return PCH_UART_HANDLED_TX_INT;
}

static unsigned int dma_handle_tx(struct eg20t_port *priv)
{
        struct uart_port *port = &priv->port;
        struct tty_port *tport = &port->state->port;
        struct scatterlist *sg;
        int nent;
        int fifo_size;
        struct dma_async_tx_descriptor *desc;
        unsigned int bytes, tail;
        int num;
        int i;
        int size;
        int rem;

        if (!priv->start_tx) {
                dev_info(priv->port.dev, "%s:Tx isn't started. (%lu)\n",
                        __func__, jiffies);
                pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_TX_INT);
                priv->tx_empty = 1;
                return 0;
        }

        if (priv->tx_dma_use) {
                dev_dbg(priv->port.dev, "%s:Tx is not completed. (%lu)\n",
                        __func__, jiffies);
                pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_TX_INT);
                priv->tx_empty = 1;
                return 0;
        }

        fifo_size = max(priv->fifo_size, 1);

        if (port->x_char) {
                iowrite8(port->x_char, priv->membase + PCH_UART_THR);
                port->icount.tx++;
                port->x_char = 0;
                fifo_size--;
        }

        bytes = kfifo_out_linear(&tport->xmit_fifo, &tail, UART_XMIT_SIZE);
        if (!bytes) {
                dev_dbg(priv->port.dev, "%s 0 bytes return\n", __func__);
                pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_TX_INT);
                uart_write_wakeup(port);
                return 0;
        }

        if (bytes > fifo_size) {
                num = bytes / fifo_size + 1;
                size = fifo_size;
                rem = bytes % fifo_size;
        } else {
                num = 1;
                size = bytes;
                rem = bytes;
        }

        dev_dbg(priv->port.dev, "%s num=%d size=%d rem=%d\n",
                __func__, num, size, rem);

        priv->tx_dma_use = 1;

        priv->sg_tx_p = kmalloc_objs(struct scatterlist, num, GFP_ATOMIC);
        if (!priv->sg_tx_p) {
                dev_err(priv->port.dev, "%s:kzalloc Failed\n", __func__);
                return 0;
        }

        sg_init_table(priv->sg_tx_p, num); /* Initialize SG table */
        sg = priv->sg_tx_p;

        for (i = 0; i < num; i++, sg++) {
                if (i == (num - 1))
                        sg_set_page(sg, virt_to_page(tport->xmit_buf),
                                    rem, fifo_size * i);
                else
                        sg_set_page(sg, virt_to_page(tport->xmit_buf),
                                    size, fifo_size * i);
        }

        sg = priv->sg_tx_p;
        nent = dma_map_sg(port->dev, sg, num, DMA_TO_DEVICE);
        if (!nent) {
                dev_err(priv->port.dev, "%s:dma_map_sg Failed\n", __func__);
                return 0;
        }
        priv->orig_nent = num;
        priv->nent = nent;

        for (i = 0; i < nent; i++, sg++) {
                sg->offset = tail + fifo_size * i;
                sg_dma_address(sg) = (sg_dma_address(sg) &
                                    ~(UART_XMIT_SIZE - 1)) + sg->offset;
                if (i == (nent - 1))
                        sg_dma_len(sg) = rem;
                else
                        sg_dma_len(sg) = size;
        }

        desc = dmaengine_prep_slave_sg(priv->chan_tx,
                                        priv->sg_tx_p, nent, DMA_MEM_TO_DEV,
                                        DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
        if (!desc) {
                dev_err(priv->port.dev, "%s:dmaengine_prep_slave_sg Failed\n",
                        __func__);
                return 0;
        }
        dma_sync_sg_for_device(port->dev, priv->sg_tx_p, num, DMA_TO_DEVICE);
        priv->desc_tx = desc;
        desc->callback = pch_dma_tx_complete;
        desc->callback_param = priv;

        desc->tx_submit(desc);

        dma_async_issue_pending(priv->chan_tx);

        return PCH_UART_HANDLED_TX_INT;
}

static void pch_uart_err_ir(struct eg20t_port *priv, unsigned int lsr)
{
        struct uart_port *port = &priv->port;
        struct tty_struct *tty = tty_port_tty_get(&port->state->port);
        char   *error_msg[5] = {};
        int    i = 0;

        if (lsr & PCH_UART_LSR_ERR)
                error_msg[i++] = "Error data in FIFO\n";

        if (lsr & UART_LSR_FE) {
                port->icount.frame++;
                error_msg[i++] = "  Framing Error\n";
        }

        if (lsr & UART_LSR_PE) {
                port->icount.parity++;
                error_msg[i++] = "  Parity Error\n";
        }

        if (lsr & UART_LSR_OE) {
                port->icount.overrun++;
                error_msg[i++] = "  Overrun Error\n";
        }

        if (tty == NULL) {
                for (i = 0; error_msg[i] != NULL; i++)
                        dev_err(&priv->pdev->dev, error_msg[i]);
        } else {
                tty_kref_put(tty);
        }
}

static irqreturn_t pch_uart_interrupt(int irq, void *dev_id)
{
        struct eg20t_port *priv = dev_id;
        unsigned int handled;
        u8 lsr;
        int ret = 0;
        unsigned char iid;
        int next = 1;
        u8 msr;

        uart_port_lock(&priv->port);
        handled = 0;
        while (next) {
                iid = pch_uart_hal_get_iid(priv);
                if (iid & PCH_UART_IIR_IP) /* No Interrupt */
                        break;
                switch (iid) {
                case PCH_UART_IID_RLS:  /* Receiver Line Status */
                        lsr = pch_uart_hal_get_line_status(priv);
                        if (lsr & (PCH_UART_LSR_ERR | UART_LSR_FE |
                                                UART_LSR_PE | UART_LSR_OE)) {
                                pch_uart_err_ir(priv, lsr);
                                ret = PCH_UART_HANDLED_RX_ERR_INT;
                        } else {
                                ret = PCH_UART_HANDLED_LS_INT;
                        }
                        break;
                case PCH_UART_IID_RDR:  /* Received Data Ready */
                        if (priv->use_dma) {
                                pch_uart_hal_disable_interrupt(priv,
                                                PCH_UART_HAL_RX_INT |
                                                PCH_UART_HAL_RX_ERR_INT);
                                ret = dma_handle_rx(priv);
                                if (!ret)
                                        pch_uart_hal_enable_interrupt(priv,
                                                PCH_UART_HAL_RX_INT |
                                                PCH_UART_HAL_RX_ERR_INT);
                        } else {
                                ret = handle_rx_to(priv);
                        }
                        break;
                case PCH_UART_IID_RDR_TO:       /* Received Data Ready
                                                   (FIFO Timeout) */
                        ret = handle_rx_to(priv);
                        break;
                case PCH_UART_IID_THRE: /* Transmitter Holding Register
                                                   Empty */
                        if (priv->use_dma)
                                ret = dma_handle_tx(priv);
                        else
                                ret = handle_tx(priv);
                        break;
                case PCH_UART_IID_MS:   /* Modem Status */
                        msr = pch_uart_hal_get_modem(priv);
                        next = 0; /* MS ir prioirty is the lowest. So, MS ir
                                     means final interrupt */
                        if ((msr & UART_MSR_ANY_DELTA) == 0)
                                break;
                        ret |= PCH_UART_HANDLED_MS_INT;
                        break;
                default:        /* Never junp to this label */
                        dev_err(priv->port.dev, "%s:iid=%02x (%lu)\n", __func__,
                                iid, jiffies);
                        ret = -1;
                        next = 0;
                        break;
                }
                handled |= (unsigned int)ret;
        }

        uart_unlock_and_check_sysrq(&priv->port);
        return IRQ_RETVAL(handled);
}

/* This function tests whether the transmitter fifo and shifter for the port
                                                described by 'port' is empty. */
static unsigned int pch_uart_tx_empty(struct uart_port *port)
{
        struct eg20t_port *priv;

        priv = container_of(port, struct eg20t_port, port);
        if (priv->tx_empty)
                return TIOCSER_TEMT;
        else
                return 0;
}

/* Returns the current state of modem control inputs. */
static unsigned int pch_uart_get_mctrl(struct uart_port *port)
{
        struct eg20t_port *priv;
        u8 modem;
        unsigned int ret = 0;

        priv = container_of(port, struct eg20t_port, port);
        modem = pch_uart_hal_get_modem(priv);

        if (modem & UART_MSR_DCD)
                ret |= TIOCM_CAR;

        if (modem & UART_MSR_RI)
                ret |= TIOCM_RNG;

        if (modem & UART_MSR_DSR)
                ret |= TIOCM_DSR;

        if (modem & UART_MSR_CTS)
                ret |= TIOCM_CTS;

        return ret;
}

static void pch_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
        u32 mcr = 0;
        struct eg20t_port *priv = container_of(port, struct eg20t_port, port);

        if (mctrl & TIOCM_DTR)
                mcr |= UART_MCR_DTR;
        if (mctrl & TIOCM_RTS)
                mcr |= UART_MCR_RTS;
        if (mctrl & TIOCM_LOOP)
                mcr |= UART_MCR_LOOP;

        if (priv->mcr & UART_MCR_AFE)
                mcr |= UART_MCR_AFE;

        if (mctrl)
                iowrite8(mcr, priv->membase + UART_MCR);
}

static void pch_uart_stop_tx(struct uart_port *port)
{
        struct eg20t_port *priv;
        priv = container_of(port, struct eg20t_port, port);
        priv->start_tx = 0;
        priv->tx_dma_use = 0;
}

static void pch_uart_start_tx(struct uart_port *port)
{
        struct eg20t_port *priv;

        priv = container_of(port, struct eg20t_port, port);

        if (priv->use_dma) {
                if (priv->tx_dma_use) {
                        dev_dbg(priv->port.dev, "%s : Tx DMA is NOT empty.\n",
                                __func__);
                        return;
                }
        }

        priv->start_tx = 1;
        pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_TX_INT);
}

static void pch_uart_stop_rx(struct uart_port *port)
{
        struct eg20t_port *priv;
        priv = container_of(port, struct eg20t_port, port);
        priv->start_rx = 0;
        pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_RX_INT |
                                             PCH_UART_HAL_RX_ERR_INT);
}

/* Enable the modem status interrupts. */
static void pch_uart_enable_ms(struct uart_port *port)
{
        struct eg20t_port *priv;
        priv = container_of(port, struct eg20t_port, port);
        pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_MS_INT);
}

/* Control the transmission of a break signal. */
static void pch_uart_break_ctl(struct uart_port *port, int ctl)
{
        struct eg20t_port *priv;
        unsigned long flags;

        priv = container_of(port, struct eg20t_port, port);
        uart_port_lock_irqsave(&priv->port, &flags);
        pch_uart_hal_set_break(priv, ctl);
        uart_port_unlock_irqrestore(&priv->port, flags);
}

/* Grab any interrupt resources and initialise any low level driver state. */
static int pch_uart_startup(struct uart_port *port)
{
        struct eg20t_port *priv;
        int ret;
        int fifo_size;
        int trigger_level;

        priv = container_of(port, struct eg20t_port, port);
        priv->tx_empty = 1;

        if (port->uartclk)
                priv->uartclk = port->uartclk;
        else
                port->uartclk = priv->uartclk;

        pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_ALL_INT);
        ret = pch_uart_hal_set_line(priv, default_baud,
                              PCH_UART_HAL_PARITY_NONE, PCH_UART_HAL_8BIT,
                              PCH_UART_HAL_STB1);
        if (ret)
                return ret;

        switch (priv->fifo_size) {
        case 256:
                fifo_size = PCH_UART_HAL_FIFO256;
                break;
        case 64:
                fifo_size = PCH_UART_HAL_FIFO64;
                break;
        case 16:
                fifo_size = PCH_UART_HAL_FIFO16;
                break;
        case 1:
        default:
                fifo_size = PCH_UART_HAL_FIFO_DIS;
                break;
        }

        switch (priv->trigger) {
        case PCH_UART_HAL_TRIGGER1:
                trigger_level = 1;
                break;
        case PCH_UART_HAL_TRIGGER_L:
                trigger_level = priv->fifo_size / 4;
                break;
        case PCH_UART_HAL_TRIGGER_M:
                trigger_level = priv->fifo_size / 2;
                break;
        case PCH_UART_HAL_TRIGGER_H:
        default:
                trigger_level = priv->fifo_size - (priv->fifo_size / 8);
                break;
        }

        priv->trigger_level = trigger_level;
        ret = pch_uart_hal_set_fifo(priv, PCH_UART_HAL_DMA_MODE0,
                                    fifo_size, priv->trigger);
        if (ret < 0)
                return ret;

        ret = request_irq(priv->port.irq, pch_uart_interrupt, IRQF_SHARED,
                        priv->irq_name, priv);
        if (ret < 0)
                return ret;

        if (priv->use_dma)
                pch_request_dma(port);

        priv->start_rx = 1;
        pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_RX_INT |
                                            PCH_UART_HAL_RX_ERR_INT);
        uart_update_timeout(port, CS8, default_baud);

        return 0;
}

static void pch_uart_shutdown(struct uart_port *port)
{
        struct eg20t_port *priv;
        int ret;

        priv = container_of(port, struct eg20t_port, port);
        pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_ALL_INT);
        pch_uart_hal_fifo_reset(priv, PCH_UART_HAL_CLR_ALL_FIFO);
        ret = pch_uart_hal_set_fifo(priv, PCH_UART_HAL_DMA_MODE0,
                              PCH_UART_HAL_FIFO_DIS, PCH_UART_HAL_TRIGGER1);
        if (ret)
                dev_err(priv->port.dev,
                        "pch_uart_hal_set_fifo Failed(ret=%d)\n", ret);

        pch_free_dma(port);

        free_irq(priv->port.irq, priv);
}

/* Change the port parameters, including word length, parity, stop
 *bits.  Update read_status_mask and ignore_status_mask to indicate
 *the types of events we are interested in receiving.  */
static void pch_uart_set_termios(struct uart_port *port,
                                 struct ktermios *termios,
                                 const struct ktermios *old)
{
        int rtn;
        unsigned int baud, parity, bits, stb;
        struct eg20t_port *priv;
        unsigned long flags;

        priv = container_of(port, struct eg20t_port, port);
        switch (termios->c_cflag & CSIZE) {
        case CS5:
                bits = PCH_UART_HAL_5BIT;
                break;
        case CS6:
                bits = PCH_UART_HAL_6BIT;
                break;
        case CS7:
                bits = PCH_UART_HAL_7BIT;
                break;
        default:                /* CS8 */
                bits = PCH_UART_HAL_8BIT;
                break;
        }
        if (termios->c_cflag & CSTOPB)
                stb = PCH_UART_HAL_STB2;
        else
                stb = PCH_UART_HAL_STB1;

        if (termios->c_cflag & PARENB) {
                if (termios->c_cflag & PARODD)
                        parity = PCH_UART_HAL_PARITY_ODD;
                else
                        parity = PCH_UART_HAL_PARITY_EVEN;

        } else
                parity = PCH_UART_HAL_PARITY_NONE;

        /* Only UART0 has auto hardware flow function */
        if ((termios->c_cflag & CRTSCTS) && (priv->fifo_size == 256))
                priv->mcr |= UART_MCR_AFE;
        else
                priv->mcr &= ~UART_MCR_AFE;

        termios->c_cflag &= ~CMSPAR; /* Mark/Space parity is not supported */

        baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);

        uart_port_lock_irqsave(port, &flags);

        uart_update_timeout(port, termios->c_cflag, baud);
        rtn = pch_uart_hal_set_line(priv, baud, parity, bits, stb);
        if (rtn)
                goto out;

        pch_uart_set_mctrl(&priv->port, priv->port.mctrl);
        /* Don't rewrite B0 */
        if (tty_termios_baud_rate(termios))
                tty_termios_encode_baud_rate(termios, baud, baud);

out:
        uart_port_unlock_irqrestore(port, flags);
}

static const char *pch_uart_type(struct uart_port *port)
{
        return KBUILD_MODNAME;
}

static void pch_uart_release_port(struct uart_port *port)
{
        struct eg20t_port *priv;

        priv = container_of(port, struct eg20t_port, port);
        pci_iounmap(priv->pdev, priv->membase);
        pci_release_regions(priv->pdev);
}

static int pch_uart_request_port(struct uart_port *port)
{
        struct eg20t_port *priv;
        int ret;
        void __iomem *membase;

        priv = container_of(port, struct eg20t_port, port);
        ret = pci_request_regions(priv->pdev, KBUILD_MODNAME);
        if (ret < 0)
                return -EBUSY;

        membase = pci_iomap(priv->pdev, 1, 0);
        if (!membase) {
                pci_release_regions(priv->pdev);
                return -EBUSY;
        }
        priv->membase = port->membase = membase;

        return 0;
}

static void pch_uart_config_port(struct uart_port *port, int type)
{
        struct eg20t_port *priv;

        priv = container_of(port, struct eg20t_port, port);
        if (type & UART_CONFIG_TYPE) {
                port->type = priv->port_type;
                pch_uart_request_port(port);
        }
}

static int pch_uart_verify_port(struct uart_port *port,
                                struct serial_struct *serinfo)
{
        struct eg20t_port *priv;

        priv = container_of(port, struct eg20t_port, port);
        if (serinfo->flags & UPF_LOW_LATENCY) {
                dev_info(priv->port.dev,
                        "PCH UART : Use PIO Mode (without DMA)\n");
                priv->use_dma = 0;
                serinfo->flags &= ~UPF_LOW_LATENCY;
        } else {
#ifndef CONFIG_PCH_DMA
                dev_err(priv->port.dev, "%s : PCH DMA is not Loaded.\n",
                        __func__);
                return -EOPNOTSUPP;
#endif
                if (!priv->use_dma) {
                        pch_request_dma(port);
                        if (priv->chan_rx)
                                priv->use_dma = 1;
                }
                dev_info(priv->port.dev, "PCH UART: %s\n",
                                priv->use_dma ?
                                "Use DMA Mode" : "No DMA");
        }

        return 0;
}

#if defined(CONFIG_CONSOLE_POLL) || defined(CONFIG_SERIAL_PCH_UART_CONSOLE)
/*
 *      Wait for transmitter & holding register to empty
 */
static void wait_for_xmitr(struct eg20t_port *up, int bits)
{
        unsigned int status, tmout = 10000;

        /* Wait up to 10ms for the character(s) to be sent. */
        for (;;) {
                status = ioread8(up->membase + UART_LSR);

                if ((status & bits) == bits)
                        break;
                if (--tmout == 0)
                        break;
                udelay(1);
        }

        /* Wait up to 1s for flow control if necessary */
        if (up->port.flags & UPF_CONS_FLOW) {
                unsigned int tmout;
                for (tmout = 1000000; tmout; tmout--) {
                        unsigned int msr = ioread8(up->membase + UART_MSR);
                        if (msr & UART_MSR_CTS)
                                break;
                        udelay(1);
                        touch_nmi_watchdog();
                }
        }
}
#endif /* CONFIG_CONSOLE_POLL || CONFIG_SERIAL_PCH_UART_CONSOLE */

#ifdef CONFIG_CONSOLE_POLL
/*
 * Console polling routines for communicate via uart while
 * in an interrupt or debug context.
 */
static int pch_uart_get_poll_char(struct uart_port *port)
{
        struct eg20t_port *priv =
                container_of(port, struct eg20t_port, port);
        u8 lsr = ioread8(priv->membase + UART_LSR);

        if (!(lsr & UART_LSR_DR))
                return NO_POLL_CHAR;

        return ioread8(priv->membase + PCH_UART_RBR);
}


static void pch_uart_put_poll_char(struct uart_port *port,
                         unsigned char c)
{
        unsigned int ier;
        struct eg20t_port *priv =
                container_of(port, struct eg20t_port, port);

        /*
         * First save the IER then disable the interrupts
         */
        ier = ioread8(priv->membase + UART_IER);
        pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_ALL_INT);

        wait_for_xmitr(priv, UART_LSR_THRE);
        /*
         * Send the character out.
         */
        iowrite8(c, priv->membase + PCH_UART_THR);

        /*
         * Finally, wait for transmitter to become empty
         * and restore the IER
         */
        wait_for_xmitr(priv, UART_LSR_BOTH_EMPTY);
        iowrite8(ier, priv->membase + UART_IER);
}
#endif /* CONFIG_CONSOLE_POLL */

static const struct uart_ops pch_uart_ops = {
        .tx_empty = pch_uart_tx_empty,
        .set_mctrl = pch_uart_set_mctrl,
        .get_mctrl = pch_uart_get_mctrl,
        .stop_tx = pch_uart_stop_tx,
        .start_tx = pch_uart_start_tx,
        .stop_rx = pch_uart_stop_rx,
        .enable_ms = pch_uart_enable_ms,
        .break_ctl = pch_uart_break_ctl,
        .startup = pch_uart_startup,
        .shutdown = pch_uart_shutdown,
        .set_termios = pch_uart_set_termios,
        .type = pch_uart_type,
        .release_port = pch_uart_release_port,
        .request_port = pch_uart_request_port,
        .config_port = pch_uart_config_port,
        .verify_port = pch_uart_verify_port,
#ifdef CONFIG_CONSOLE_POLL
        .poll_get_char = pch_uart_get_poll_char,
        .poll_put_char = pch_uart_put_poll_char,
#endif
};

#ifdef CONFIG_SERIAL_PCH_UART_CONSOLE

static void pch_console_putchar(struct uart_port *port, unsigned char ch)
{
        struct eg20t_port *priv =
                container_of(port, struct eg20t_port, port);

        wait_for_xmitr(priv, UART_LSR_THRE);
        iowrite8(ch, priv->membase + PCH_UART_THR);
}

/*
 *      Print a string to the serial port trying not to disturb
 *      any possible real use of the port...
 *
 *      The console_lock must be held when we get here.
 */
static void
pch_console_write(struct console *co, const char *s, unsigned int count)
{
        struct eg20t_port *priv;
        unsigned long flags;
        int locked = 1;
        u8 ier;

        priv = pch_uart_ports[co->index];

        touch_nmi_watchdog();

        if (oops_in_progress)
                locked = uart_port_trylock_irqsave(&priv->port, &flags);
        else
                uart_port_lock_irqsave(&priv->port, &flags);

        /*
         *      First save the IER then disable the interrupts
         */
        ier = ioread8(priv->membase + UART_IER);

        pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_ALL_INT);

        uart_console_write(&priv->port, s, count, pch_console_putchar);

        /*
         *      Finally, wait for transmitter to become empty
         *      and restore the IER
         */
        wait_for_xmitr(priv, UART_LSR_BOTH_EMPTY);
        iowrite8(ier, priv->membase + UART_IER);

        if (locked)
                uart_port_unlock_irqrestore(&priv->port, flags);
}

static int __init pch_console_setup(struct console *co, char *options)
{
        struct uart_port *port;
        int baud = default_baud;
        int bits = 8;
        int parity = 'n';
        int flow = 'n';

        /*
         * Check whether an invalid uart number has been specified, and
         * if so, search for the first available port that does have
         * console support.
         */
        if (co->index >= PCH_UART_NR)
                co->index = 0;
        port = &pch_uart_ports[co->index]->port;

        if (!port || (!port->iobase && !port->membase))
                return -ENODEV;

        port->uartclk = pch_uart_get_uartclk();

        if (options)
                uart_parse_options(options, &baud, &parity, &bits, &flow);

        return uart_set_options(port, co, baud, parity, bits, flow);
}

static struct uart_driver pch_uart_driver;

static struct console pch_console = {
        .name           = PCH_UART_DRIVER_DEVICE,
        .write          = pch_console_write,
        .device         = uart_console_device,
        .setup          = pch_console_setup,
        .flags          = CON_PRINTBUFFER | CON_ANYTIME,
        .index          = -1,
        .data           = &pch_uart_driver,
};

#define PCH_CONSOLE     (&pch_console)
#else
#define PCH_CONSOLE     NULL
#endif  /* CONFIG_SERIAL_PCH_UART_CONSOLE */

static struct uart_driver pch_uart_driver = {
        .owner = THIS_MODULE,
        .driver_name = KBUILD_MODNAME,
        .dev_name = PCH_UART_DRIVER_DEVICE,
        .major = 0,
        .minor = 0,
        .nr = PCH_UART_NR,
        .cons = PCH_CONSOLE,
};

static struct eg20t_port *pch_uart_init_port(struct pci_dev *pdev,
                                             const struct pci_device_id *id)
{
        struct eg20t_port *priv;
        int ret;
        unsigned int iobase;
        unsigned int mapbase;
        unsigned char *rxbuf;
        int fifosize;
        int port_type;
        struct pch_uart_driver_data *board;
        char name[32];

        board = &drv_dat[id->driver_data];
        port_type = board->port_type;

        priv = kzalloc_obj(struct eg20t_port);
        if (priv == NULL)
                goto init_port_alloc_err;

        rxbuf = (unsigned char *)__get_free_page(GFP_KERNEL);
        if (!rxbuf)
                goto init_port_free_txbuf;

        switch (port_type) {
        case PORT_PCH_8LINE:
                fifosize = 256; /* EG20T/ML7213: UART0 */
                break;
        case PORT_PCH_2LINE:
                fifosize = 64; /* EG20T:UART1~3  ML7213: UART1~2*/
                break;
        default:
                dev_err(&pdev->dev, "Invalid Port Type(=%d)\n", port_type);
                goto init_port_hal_free;
        }

        pci_enable_msi(pdev);
        pci_set_master(pdev);

        iobase = pci_resource_start(pdev, 0);
        mapbase = pci_resource_start(pdev, 1);
        priv->mapbase = mapbase;
        priv->iobase = iobase;
        priv->pdev = pdev;
        priv->tx_empty = 1;
        priv->rxbuf.buf = rxbuf;
        priv->rxbuf.size = PAGE_SIZE;

        priv->fifo_size = fifosize;
        priv->uartclk = pch_uart_get_uartclk();
        priv->port_type = port_type;
        priv->port.dev = &pdev->dev;
        priv->port.iobase = iobase;
        priv->port.membase = NULL;
        priv->port.mapbase = mapbase;
        priv->port.irq = pdev->irq;
        priv->port.iotype = UPIO_PORT;
        priv->port.ops = &pch_uart_ops;
        priv->port.flags = UPF_BOOT_AUTOCONF;
        priv->port.fifosize = fifosize;
        priv->port.line = board->line_no;
        priv->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_PCH_UART_CONSOLE);
        priv->trigger = PCH_UART_HAL_TRIGGER_M;

        snprintf(priv->irq_name, IRQ_NAME_SIZE,
                 KBUILD_MODNAME ":" PCH_UART_DRIVER_DEVICE "%d",
                 priv->port.line);

        pci_set_drvdata(pdev, priv);
        priv->trigger_level = 1;
        priv->fcr = 0;

        if (pdev->dev.of_node)
                of_property_read_u32(pdev->dev.of_node, "clock-frequency"
                                         , &user_uartclk);

#ifdef CONFIG_SERIAL_PCH_UART_CONSOLE
        pch_uart_ports[board->line_no] = priv;
#endif
        ret = uart_add_one_port(&pch_uart_driver, &priv->port);
        if (ret < 0)
                goto init_port_hal_free;

        snprintf(name, sizeof(name), "uart%d_regs", priv->port.line);
        debugfs_create_file(name, S_IFREG | S_IRUGO, NULL, priv,
                            &port_regs_ops);

        return priv;

init_port_hal_free:
#ifdef CONFIG_SERIAL_PCH_UART_CONSOLE
        pch_uart_ports[board->line_no] = NULL;
#endif
        free_page((unsigned long)rxbuf);
init_port_free_txbuf:
        kfree(priv);
init_port_alloc_err:

        return NULL;
}

static void pch_uart_exit_port(struct eg20t_port *priv)
{
        char name[32];

        snprintf(name, sizeof(name), "uart%d_regs", priv->port.line);
        debugfs_lookup_and_remove(name, NULL);
        uart_remove_one_port(&pch_uart_driver, &priv->port);
        free_page((unsigned long)priv->rxbuf.buf);
}

static void pch_uart_pci_remove(struct pci_dev *pdev)
{
        struct eg20t_port *priv = pci_get_drvdata(pdev);

        pci_disable_msi(pdev);

#ifdef CONFIG_SERIAL_PCH_UART_CONSOLE
        pch_uart_ports[priv->port.line] = NULL;
#endif
        pch_uart_exit_port(priv);
        pci_disable_device(pdev);
        kfree(priv);
        return;
}

static int __maybe_unused pch_uart_pci_suspend(struct device *dev)
{
        struct eg20t_port *priv = dev_get_drvdata(dev);

        uart_suspend_port(&pch_uart_driver, &priv->port);

        return 0;
}

static int __maybe_unused pch_uart_pci_resume(struct device *dev)
{
        struct eg20t_port *priv = dev_get_drvdata(dev);

        uart_resume_port(&pch_uart_driver, &priv->port);

        return 0;
}

static const struct pci_device_id pch_uart_pci_id[] = {
        {PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x8811),
         .driver_data = pch_et20t_uart0},
        {PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x8812),
         .driver_data = pch_et20t_uart1},
        {PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x8813),
         .driver_data = pch_et20t_uart2},
        {PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x8814),
         .driver_data = pch_et20t_uart3},
        {PCI_DEVICE(PCI_VENDOR_ID_ROHM, 0x8027),
         .driver_data = pch_ml7213_uart0},
        {PCI_DEVICE(PCI_VENDOR_ID_ROHM, 0x8028),
         .driver_data = pch_ml7213_uart1},
        {PCI_DEVICE(PCI_VENDOR_ID_ROHM, 0x8029),
         .driver_data = pch_ml7213_uart2},
        {PCI_DEVICE(PCI_VENDOR_ID_ROHM, 0x800C),
         .driver_data = pch_ml7223_uart0},
        {PCI_DEVICE(PCI_VENDOR_ID_ROHM, 0x800D),
         .driver_data = pch_ml7223_uart1},
        {PCI_DEVICE(PCI_VENDOR_ID_ROHM, 0x8811),
         .driver_data = pch_ml7831_uart0},
        {PCI_DEVICE(PCI_VENDOR_ID_ROHM, 0x8812),
         .driver_data = pch_ml7831_uart1},
        {0,},
};

static int pch_uart_pci_probe(struct pci_dev *pdev,
                                        const struct pci_device_id *id)
{
        int ret;
        struct eg20t_port *priv;

        ret = pci_enable_device(pdev);
        if (ret < 0)
                goto probe_error;

        priv = pch_uart_init_port(pdev, id);
        if (!priv) {
                ret = -EBUSY;
                goto probe_disable_device;
        }
        pci_set_drvdata(pdev, priv);

        return ret;

probe_disable_device:
        pci_disable_msi(pdev);
        pci_disable_device(pdev);
probe_error:
        return ret;
}

static SIMPLE_DEV_PM_OPS(pch_uart_pci_pm_ops,
                         pch_uart_pci_suspend,
                         pch_uart_pci_resume);

static struct pci_driver pch_uart_pci_driver = {
        .name = "pch_uart",
        .id_table = pch_uart_pci_id,
        .probe = pch_uart_pci_probe,
        .remove = pch_uart_pci_remove,
        .driver.pm = &pch_uart_pci_pm_ops,
};

static int __init pch_uart_module_init(void)
{
        int ret;

        /* register as UART driver */
        ret = uart_register_driver(&pch_uart_driver);
        if (ret < 0)
                return ret;

        /* register as PCI driver */
        ret = pci_register_driver(&pch_uart_pci_driver);
        if (ret < 0)
                uart_unregister_driver(&pch_uart_driver);

        return ret;
}
module_init(pch_uart_module_init);

static void __exit pch_uart_module_exit(void)
{
        pci_unregister_driver(&pch_uart_pci_driver);
        uart_unregister_driver(&pch_uart_driver);
}
module_exit(pch_uart_module_exit);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Intel EG20T PCH UART PCI Driver");
MODULE_DEVICE_TABLE(pci, pch_uart_pci_id);

module_param(default_baud, uint, S_IRUGO);
MODULE_PARM_DESC(default_baud,
                 "Default BAUD for initial driver state and console (default 9600)");
module_param(user_uartclk, uint, S_IRUGO);
MODULE_PARM_DESC(user_uartclk,
                 "Override UART default or board specific UART clock");