/*
 * Copyright (C) 2005 Stephen Street / StreetFire Sound Labs
 * Copyright (C) 2013, Intel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/ioport.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/spi/pxa2xx_spi.h>
#include <linux/spi/spi.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/pm_runtime.h>
#include <linux/acpi.h>

#include "spi-pxa2xx.h"

MODULE_AUTHOR("Stephen Street");
MODULE_DESCRIPTION("PXA2xx SSP SPI Controller");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pxa2xx-spi");

#define TIMOUT_DFLT             1000

/*
 * for testing SSCR1 changes that require SSP restart, basically
 * everything except the service and interrupt enables, the pxa270 developer
 * manual says only SSCR1_SCFR, SSCR1_SPH, SSCR1_SPO need to be in this
 * list, but the PXA255 dev man says all bits without really meaning the
 * service and interrupt enables
 */
#define SSCR1_CHANGE_MASK (SSCR1_TTELP | SSCR1_TTE | SSCR1_SCFR \
                                | SSCR1_ECRA | SSCR1_ECRB | SSCR1_SCLKDIR \
                                | SSCR1_SFRMDIR | SSCR1_RWOT | SSCR1_TRAIL \
                                | SSCR1_IFS | SSCR1_STRF | SSCR1_EFWR \
                                | SSCR1_RFT | SSCR1_TFT | SSCR1_MWDS \
                                | SSCR1_SPH | SSCR1_SPO | SSCR1_LBM)

#define QUARK_X1000_SSCR1_CHANGE_MASK (QUARK_X1000_SSCR1_STRF   \
                                | QUARK_X1000_SSCR1_EFWR        \
                                | QUARK_X1000_SSCR1_RFT         \
                                | QUARK_X1000_SSCR1_TFT         \
                                | SSCR1_SPH | SSCR1_SPO | SSCR1_LBM)

#define CE4100_SSCR1_CHANGE_MASK (SSCR1_TTELP | SSCR1_TTE | SSCR1_SCFR \
                                | SSCR1_ECRA | SSCR1_ECRB | SSCR1_SCLKDIR \
                                | SSCR1_SFRMDIR | SSCR1_RWOT | SSCR1_TRAIL \
                                | SSCR1_IFS | SSCR1_STRF | SSCR1_EFWR \
                                | CE4100_SSCR1_RFT | CE4100_SSCR1_TFT | SSCR1_MWDS \
                                | SSCR1_SPH | SSCR1_SPO | SSCR1_LBM)

#define LPSS_GENERAL_REG_RXTO_HOLDOFF_DISABLE   BIT(24)
#define LPSS_CS_CONTROL_SW_MODE                 BIT(0)
#define LPSS_CS_CONTROL_CS_HIGH                 BIT(1)
#define LPSS_CAPS_CS_EN_SHIFT                   9
#define LPSS_CAPS_CS_EN_MASK                    (0xf << LPSS_CAPS_CS_EN_SHIFT)

struct lpss_config {
        /* LPSS offset from drv_data->ioaddr */
        unsigned offset;
        /* Register offsets from drv_data->lpss_base or -1 */
        int reg_general;
        int reg_ssp;
        int reg_cs_ctrl;
        int reg_capabilities;
        /* FIFO thresholds */
        u32 rx_threshold;
        u32 tx_threshold_lo;
        u32 tx_threshold_hi;
        /* Chip select control */
        unsigned cs_sel_shift;
        unsigned cs_sel_mask;
        unsigned cs_num;
};

/* Keep these sorted with enum pxa_ssp_type */
static const struct lpss_config lpss_platforms[] = {
        {       /* LPSS_LPT_SSP */
                .offset = 0x800,
                .reg_general = 0x08,
                .reg_ssp = 0x0c,
                .reg_cs_ctrl = 0x18,
                .reg_capabilities = -1,
                .rx_threshold = 64,
                .tx_threshold_lo = 160,
                .tx_threshold_hi = 224,
        },
        {       /* LPSS_BYT_SSP */
                .offset = 0x400,
                .reg_general = 0x08,
                .reg_ssp = 0x0c,
                .reg_cs_ctrl = 0x18,
                .reg_capabilities = -1,
                .rx_threshold = 64,
                .tx_threshold_lo = 160,
                .tx_threshold_hi = 224,
        },
        {       /* LPSS_BSW_SSP */
                .offset = 0x400,
                .reg_general = 0x08,
                .reg_ssp = 0x0c,
                .reg_cs_ctrl = 0x18,
                .reg_capabilities = -1,
                .rx_threshold = 64,
                .tx_threshold_lo = 160,
                .tx_threshold_hi = 224,
                .cs_sel_shift = 2,
                .cs_sel_mask = 1 << 2,
                .cs_num = 2,
        },
        {       /* LPSS_SPT_SSP */
                .offset = 0x200,
                .reg_general = -1,
                .reg_ssp = 0x20,
                .reg_cs_ctrl = 0x24,
                .reg_capabilities = -1,
                .rx_threshold = 1,
                .tx_threshold_lo = 32,
                .tx_threshold_hi = 56,
        },
        {       /* LPSS_BXT_SSP */
                .offset = 0x200,
                .reg_general = -1,
                .reg_ssp = 0x20,
                .reg_cs_ctrl = 0x24,
                .reg_capabilities = 0xfc,
                .rx_threshold = 1,
                .tx_threshold_lo = 16,
                .tx_threshold_hi = 48,
                .cs_sel_shift = 8,
                .cs_sel_mask = 3 << 8,
        },
};

static inline const struct lpss_config
*lpss_get_config(const struct driver_data *drv_data)
{
        return &lpss_platforms[drv_data->ssp_type - LPSS_LPT_SSP];
}

static bool is_lpss_ssp(const struct driver_data *drv_data)
{
        switch (drv_data->ssp_type) {
        case LPSS_LPT_SSP:
        case LPSS_BYT_SSP:
        case LPSS_BSW_SSP:
        case LPSS_SPT_SSP:
        case LPSS_BXT_SSP:
                return true;
        default:
                return false;
        }
}

static bool is_quark_x1000_ssp(const struct driver_data *drv_data)
{
        return drv_data->ssp_type == QUARK_X1000_SSP;
}

static u32 pxa2xx_spi_get_ssrc1_change_mask(const struct driver_data *drv_data)
{
        switch (drv_data->ssp_type) {
        case QUARK_X1000_SSP:
                return QUARK_X1000_SSCR1_CHANGE_MASK;
        case CE4100_SSP:
                return CE4100_SSCR1_CHANGE_MASK;
        default:
                return SSCR1_CHANGE_MASK;
        }
}

static u32
pxa2xx_spi_get_rx_default_thre(const struct driver_data *drv_data)
{
        switch (drv_data->ssp_type) {
        case QUARK_X1000_SSP:
                return RX_THRESH_QUARK_X1000_DFLT;
        case CE4100_SSP:
                return RX_THRESH_CE4100_DFLT;
        default:
                return RX_THRESH_DFLT;
        }
}

static bool pxa2xx_spi_txfifo_full(const struct driver_data *drv_data)
{
        u32 mask;

        switch (drv_data->ssp_type) {
        case QUARK_X1000_SSP:
                mask = QUARK_X1000_SSSR_TFL_MASK;
                break;
        case CE4100_SSP:
                mask = CE4100_SSSR_TFL_MASK;
                break;
        default:
                mask = SSSR_TFL_MASK;
                break;
        }

        return (pxa2xx_spi_read(drv_data, SSSR) & mask) == mask;
}

static void pxa2xx_spi_clear_rx_thre(const struct driver_data *drv_data,
                                     u32 *sccr1_reg)
{
        u32 mask;

        switch (drv_data->ssp_type) {
        case QUARK_X1000_SSP:
                mask = QUARK_X1000_SSCR1_RFT;
                break;
        case CE4100_SSP:
                mask = CE4100_SSCR1_RFT;
                break;
        default:
                mask = SSCR1_RFT;
                break;
        }
        *sccr1_reg &= ~mask;
}

static void pxa2xx_spi_set_rx_thre(const struct driver_data *drv_data,
                                   u32 *sccr1_reg, u32 threshold)
{
        switch (drv_data->ssp_type) {
        case QUARK_X1000_SSP:
                *sccr1_reg |= QUARK_X1000_SSCR1_RxTresh(threshold);
                break;
        case CE4100_SSP:
                *sccr1_reg |= CE4100_SSCR1_RxTresh(threshold);
                break;
        default:
                *sccr1_reg |= SSCR1_RxTresh(threshold);
                break;
        }
}

static u32 pxa2xx_configure_sscr0(const struct driver_data *drv_data,
                                  u32 clk_div, u8 bits)
{
        switch (drv_data->ssp_type) {
        case QUARK_X1000_SSP:
                return clk_div
                        | QUARK_X1000_SSCR0_Motorola
                        | QUARK_X1000_SSCR0_DataSize(bits > 32 ? 8 : bits)
                        | SSCR0_SSE;
        default:
                return clk_div
                        | SSCR0_Motorola
                        | SSCR0_DataSize(bits > 16 ? bits - 16 : bits)
                        | SSCR0_SSE
                        | (bits > 16 ? SSCR0_EDSS : 0);
        }
}

/*
 * Read and write LPSS SSP private registers. Caller must first check that
 * is_lpss_ssp() returns true before these can be called.
 */
static u32 __lpss_ssp_read_priv(struct driver_data *drv_data, unsigned offset)
{
        WARN_ON(!drv_data->lpss_base);
        return readl(drv_data->lpss_base + offset);
}

static void __lpss_ssp_write_priv(struct driver_data *drv_data,
                                  unsigned offset, u32 value)
{
        WARN_ON(!drv_data->lpss_base);
        writel(value, drv_data->lpss_base + offset);
}

/*
 * lpss_ssp_setup - perform LPSS SSP specific setup
 * @drv_data: pointer to the driver private data
 *
 * Perform LPSS SSP specific setup. This function must be called first if
 * one is going to use LPSS SSP private registers.
 */
static void lpss_ssp_setup(struct driver_data *drv_data)
{
        const struct lpss_config *config;
        u32 value;

        config = lpss_get_config(drv_data);
        drv_data->lpss_base = drv_data->ioaddr + config->offset;

        /* Enable software chip select control */
        value = __lpss_ssp_read_priv(drv_data, config->reg_cs_ctrl);
        value &= ~(LPSS_CS_CONTROL_SW_MODE | LPSS_CS_CONTROL_CS_HIGH);
        value |= LPSS_CS_CONTROL_SW_MODE | LPSS_CS_CONTROL_CS_HIGH;
        __lpss_ssp_write_priv(drv_data, config->reg_cs_ctrl, value);

        /* Enable multiblock DMA transfers */
        if (drv_data->master_info->enable_dma) {
                __lpss_ssp_write_priv(drv_data, config->reg_ssp, 1);

                if (config->reg_general >= 0) {
                        value = __lpss_ssp_read_priv(drv_data,
                                                     config->reg_general);
                        value |= LPSS_GENERAL_REG_RXTO_HOLDOFF_DISABLE;
                        __lpss_ssp_write_priv(drv_data,
                                              config->reg_general, value);
                }
        }
}

static void lpss_ssp_select_cs(struct driver_data *drv_data,
                               const struct lpss_config *config)
{
        u32 value, cs;

        if (!config->cs_sel_mask)
                return;

        value = __lpss_ssp_read_priv(drv_data, config->reg_cs_ctrl);

        cs = drv_data->master->cur_msg->spi->chip_select;
        cs <<= config->cs_sel_shift;
        if (cs != (value & config->cs_sel_mask)) {
                /*
                 * When switching another chip select output active the
                 * output must be selected first and wait 2 ssp_clk cycles
                 * before changing state to active. Otherwise a short
                 * glitch will occur on the previous chip select since
                 * output select is latched but state control is not.
                 */
                value &= ~config->cs_sel_mask;
                value |= cs;
                __lpss_ssp_write_priv(drv_data,
                                      config->reg_cs_ctrl, value);
                ndelay(1000000000 /
                       (drv_data->master->max_speed_hz / 2));
        }
}

static void lpss_ssp_cs_control(struct driver_data *drv_data, bool enable)
{
        const struct lpss_config *config;
        u32 value;

        config = lpss_get_config(drv_data);

        if (enable)
                lpss_ssp_select_cs(drv_data, config);

        value = __lpss_ssp_read_priv(drv_data, config->reg_cs_ctrl);
        if (enable)
                value &= ~LPSS_CS_CONTROL_CS_HIGH;
        else
                value |= LPSS_CS_CONTROL_CS_HIGH;
        __lpss_ssp_write_priv(drv_data, config->reg_cs_ctrl, value);
}

static void cs_assert(struct driver_data *drv_data)
{
        struct chip_data *chip =
                spi_get_ctldata(drv_data->master->cur_msg->spi);

        if (drv_data->ssp_type == CE4100_SSP) {
                pxa2xx_spi_write(drv_data, SSSR, chip->frm);
                return;
        }

        if (chip->cs_control) {
                chip->cs_control(PXA2XX_CS_ASSERT);
                return;
        }

        if (gpio_is_valid(chip->gpio_cs)) {
                gpio_set_value(chip->gpio_cs, chip->gpio_cs_inverted);
                return;
        }

        if (is_lpss_ssp(drv_data))
                lpss_ssp_cs_control(drv_data, true);
}

static void cs_deassert(struct driver_data *drv_data)
{
        struct chip_data *chip =
                spi_get_ctldata(drv_data->master->cur_msg->spi);

        if (drv_data->ssp_type == CE4100_SSP)
                return;

        if (chip->cs_control) {
                chip->cs_control(PXA2XX_CS_DEASSERT);
                return;
        }

        if (gpio_is_valid(chip->gpio_cs)) {
                gpio_set_value(chip->gpio_cs, !chip->gpio_cs_inverted);
                return;
        }

        if (is_lpss_ssp(drv_data))
                lpss_ssp_cs_control(drv_data, false);
}

int pxa2xx_spi_flush(struct driver_data *drv_data)
{
        unsigned long limit = loops_per_jiffy << 1;

        do {
                while (pxa2xx_spi_read(drv_data, SSSR) & SSSR_RNE)
                        pxa2xx_spi_read(drv_data, SSDR);
        } while ((pxa2xx_spi_read(drv_data, SSSR) & SSSR_BSY) && --limit);
        write_SSSR_CS(drv_data, SSSR_ROR);

        return limit;
}

static int null_writer(struct driver_data *drv_data)
{
        u8 n_bytes = drv_data->n_bytes;

        if (pxa2xx_spi_txfifo_full(drv_data)
                || (drv_data->tx == drv_data->tx_end))
                return 0;

        pxa2xx_spi_write(drv_data, SSDR, 0);
        drv_data->tx += n_bytes;

        return 1;
}

static int null_reader(struct driver_data *drv_data)
{
        u8 n_bytes = drv_data->n_bytes;

        while ((pxa2xx_spi_read(drv_data, SSSR) & SSSR_RNE)
               && (drv_data->rx < drv_data->rx_end)) {
                pxa2xx_spi_read(drv_data, SSDR);
                drv_data->rx += n_bytes;
        }

        return drv_data->rx == drv_data->rx_end;
}

static int u8_writer(struct driver_data *drv_data)
{
        if (pxa2xx_spi_txfifo_full(drv_data)
                || (drv_data->tx == drv_data->tx_end))
                return 0;

        pxa2xx_spi_write(drv_data, SSDR, *(u8 *)(drv_data->tx));
        ++drv_data->tx;

        return 1;
}

static int u8_reader(struct driver_data *drv_data)
{
        while ((pxa2xx_spi_read(drv_data, SSSR) & SSSR_RNE)
               && (drv_data->rx < drv_data->rx_end)) {
                *(u8 *)(drv_data->rx) = pxa2xx_spi_read(drv_data, SSDR);
                ++drv_data->rx;
        }

        return drv_data->rx == drv_data->rx_end;
}

static int u16_writer(struct driver_data *drv_data)
{
        if (pxa2xx_spi_txfifo_full(drv_data)
                || (drv_data->tx == drv_data->tx_end))
                return 0;

        pxa2xx_spi_write(drv_data, SSDR, *(u16 *)(drv_data->tx));
        drv_data->tx += 2;

        return 1;
}

static int u16_reader(struct driver_data *drv_data)
{
        while ((pxa2xx_spi_read(drv_data, SSSR) & SSSR_RNE)
               && (drv_data->rx < drv_data->rx_end)) {
                *(u16 *)(drv_data->rx) = pxa2xx_spi_read(drv_data, SSDR);
                drv_data->rx += 2;
        }

        return drv_data->rx == drv_data->rx_end;
}

static int u32_writer(struct driver_data *drv_data)
{
        if (pxa2xx_spi_txfifo_full(drv_data)
                || (drv_data->tx == drv_data->tx_end))
                return 0;

        pxa2xx_spi_write(drv_data, SSDR, *(u32 *)(drv_data->tx));
        drv_data->tx += 4;

        return 1;
}

static int u32_reader(struct driver_data *drv_data)
{
        while ((pxa2xx_spi_read(drv_data, SSSR) & SSSR_RNE)
               && (drv_data->rx < drv_data->rx_end)) {
                *(u32 *)(drv_data->rx) = pxa2xx_spi_read(drv_data, SSDR);
                drv_data->rx += 4;
        }

        return drv_data->rx == drv_data->rx_end;
}

void *pxa2xx_spi_next_transfer(struct driver_data *drv_data)
{
        struct spi_message *msg = drv_data->master->cur_msg;
        struct spi_transfer *trans = drv_data->cur_transfer;

        /* Move to next transfer */
        if (trans->transfer_list.next != &msg->transfers) {
                drv_data->cur_transfer =
                        list_entry(trans->transfer_list.next,
                                        struct spi_transfer,
                                        transfer_list);
                return RUNNING_STATE;
        } else
                return DONE_STATE;
}

/* caller already set message->status; dma and pio irqs are blocked */
static void giveback(struct driver_data *drv_data)
{
        struct spi_transfer* last_transfer;
        struct spi_message *msg;
        unsigned long timeout;

        msg = drv_data->master->cur_msg;
        drv_data->cur_transfer = NULL;

        last_transfer = list_last_entry(&msg->transfers, struct spi_transfer,
                                        transfer_list);

        /* Delay if requested before any change in chip select */
        if (last_transfer->delay_usecs)
                udelay(last_transfer->delay_usecs);

        /* Wait until SSP becomes idle before deasserting the CS */
        timeout = jiffies + msecs_to_jiffies(10);
        while (pxa2xx_spi_read(drv_data, SSSR) & SSSR_BSY &&
               !time_after(jiffies, timeout))
                cpu_relax();

        /* Drop chip select UNLESS cs_change is true or we are returning
         * a message with an error, or next message is for another chip
         */
        if (!last_transfer->cs_change)
                cs_deassert(drv_data);
        else {
                struct spi_message *next_msg;

                /* Holding of cs was hinted, but we need to make sure
                 * the next message is for the same chip.  Don't waste
                 * time with the following tests unless this was hinted.
                 *
                 * We cannot postpone this until pump_messages, because
                 * after calling msg->complete (below) the driver that
                 * sent the current message could be unloaded, which
                 * could invalidate the cs_control() callback...
                 */

                /* get a pointer to the next message, if any */
                next_msg = spi_get_next_queued_message(drv_data->master);

                /* see if the next and current messages point
                 * to the same chip
                 */
                if ((next_msg && next_msg->spi != msg->spi) ||
                    msg->state == ERROR_STATE)
                        cs_deassert(drv_data);
        }

        spi_finalize_current_message(drv_data->master);
}

static void reset_sccr1(struct driver_data *drv_data)
{
        struct chip_data *chip =
                spi_get_ctldata(drv_data->master->cur_msg->spi);
        u32 sccr1_reg;

        sccr1_reg = pxa2xx_spi_read(drv_data, SSCR1) & ~drv_data->int_cr1;
        switch (drv_data->ssp_type) {
        case QUARK_X1000_SSP:
                sccr1_reg &= ~QUARK_X1000_SSCR1_RFT;
                break;
        case CE4100_SSP:
                sccr1_reg &= ~CE4100_SSCR1_RFT;
                break;
        default:
                sccr1_reg &= ~SSCR1_RFT;
                break;
        }
        sccr1_reg |= chip->threshold;
        pxa2xx_spi_write(drv_data, SSCR1, sccr1_reg);
}

static void int_error_stop(struct driver_data *drv_data, const char* msg)
{
        /* Stop and reset SSP */
        write_SSSR_CS(drv_data, drv_data->clear_sr);
        reset_sccr1(drv_data);
        if (!pxa25x_ssp_comp(drv_data))
                pxa2xx_spi_write(drv_data, SSTO, 0);
        pxa2xx_spi_flush(drv_data);
        pxa2xx_spi_write(drv_data, SSCR0,
                         pxa2xx_spi_read(drv_data, SSCR0) & ~SSCR0_SSE);

        dev_err(&drv_data->pdev->dev, "%s\n", msg);

        drv_data->master->cur_msg->state = ERROR_STATE;
        tasklet_schedule(&drv_data->pump_transfers);
}

static void int_transfer_complete(struct driver_data *drv_data)
{
        /* Clear and disable interrupts */
        write_SSSR_CS(drv_data, drv_data->clear_sr);
        reset_sccr1(drv_data);
        if (!pxa25x_ssp_comp(drv_data))
                pxa2xx_spi_write(drv_data, SSTO, 0);

        /* Update total byte transferred return count actual bytes read */
        drv_data->master->cur_msg->actual_length += drv_data->len -
                                (drv_data->rx_end - drv_data->rx);

        /* Transfer delays and chip select release are
         * handled in pump_transfers or giveback
         */

        /* Move to next transfer */
        drv_data->master->cur_msg->state = pxa2xx_spi_next_transfer(drv_data);

        /* Schedule transfer tasklet */
        tasklet_schedule(&drv_data->pump_transfers);
}

static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
{
        u32 irq_mask = (pxa2xx_spi_read(drv_data, SSCR1) & SSCR1_TIE) ?
                       drv_data->mask_sr : drv_data->mask_sr & ~SSSR_TFS;

        u32 irq_status = pxa2xx_spi_read(drv_data, SSSR) & irq_mask;

        if (irq_status & SSSR_ROR) {
                int_error_stop(drv_data, "interrupt_transfer: fifo overrun");
                return IRQ_HANDLED;
        }

        if (irq_status & SSSR_TINT) {
                pxa2xx_spi_write(drv_data, SSSR, SSSR_TINT);
                if (drv_data->read(drv_data)) {
                        int_transfer_complete(drv_data);
                        return IRQ_HANDLED;
                }
        }

        /* Drain rx fifo, Fill tx fifo and prevent overruns */
        do {
                if (drv_data->read(drv_data)) {
                        int_transfer_complete(drv_data);
                        return IRQ_HANDLED;
                }
        } while (drv_data->write(drv_data));

        if (drv_data->read(drv_data)) {
                int_transfer_complete(drv_data);
                return IRQ_HANDLED;
        }

        if (drv_data->tx == drv_data->tx_end) {
                u32 bytes_left;
                u32 sccr1_reg;

                sccr1_reg = pxa2xx_spi_read(drv_data, SSCR1);
                sccr1_reg &= ~SSCR1_TIE;

                /*
                 * PXA25x_SSP has no timeout, set up rx threshould for the
                 * remaining RX bytes.
                 */
                if (pxa25x_ssp_comp(drv_data)) {
                        u32 rx_thre;

                        pxa2xx_spi_clear_rx_thre(drv_data, &sccr1_reg);

                        bytes_left = drv_data->rx_end - drv_data->rx;
                        switch (drv_data->n_bytes) {
                        case 4:
                                bytes_left >>= 1;
                        case 2:
                                bytes_left >>= 1;
                        }

                        rx_thre = pxa2xx_spi_get_rx_default_thre(drv_data);
                        if (rx_thre > bytes_left)
                                rx_thre = bytes_left;

                        pxa2xx_spi_set_rx_thre(drv_data, &sccr1_reg, rx_thre);
                }
                pxa2xx_spi_write(drv_data, SSCR1, sccr1_reg);
        }

        /* We did something */
        return IRQ_HANDLED;
}

static irqreturn_t ssp_int(int irq, void *dev_id)
{
        struct driver_data *drv_data = dev_id;
        u32 sccr1_reg;
        u32 mask = drv_data->mask_sr;
        u32 status;

        /*
         * The IRQ might be shared with other peripherals so we must first
         * check that are we RPM suspended or not. If we are we assume that
         * the IRQ was not for us (we shouldn't be RPM suspended when the
         * interrupt is enabled).
         */
        if (pm_runtime_suspended(&drv_data->pdev->dev))
                return IRQ_NONE;

        /*
         * If the device is not yet in RPM suspended state and we get an
         * interrupt that is meant for another device, check if status bits
         * are all set to one. That means that the device is already
         * powered off.
         */
        status = pxa2xx_spi_read(drv_data, SSSR);
        if (status == ~0)
                return IRQ_NONE;

        sccr1_reg = pxa2xx_spi_read(drv_data, SSCR1);

        /* Ignore possible writes if we don't need to write */
        if (!(sccr1_reg & SSCR1_TIE))
                mask &= ~SSSR_TFS;

        /* Ignore RX timeout interrupt if it is disabled */
        if (!(sccr1_reg & SSCR1_TINTE))
                mask &= ~SSSR_TINT;

        if (!(status & mask))
                return IRQ_NONE;

        if (!drv_data->master->cur_msg) {

                pxa2xx_spi_write(drv_data, SSCR0,
                                 pxa2xx_spi_read(drv_data, SSCR0)
                                 & ~SSCR0_SSE);
                pxa2xx_spi_write(drv_data, SSCR1,
                                 pxa2xx_spi_read(drv_data, SSCR1)
                                 & ~drv_data->int_cr1);
                if (!pxa25x_ssp_comp(drv_data))
                        pxa2xx_spi_write(drv_data, SSTO, 0);
                write_SSSR_CS(drv_data, drv_data->clear_sr);

                dev_err(&drv_data->pdev->dev,
                        "bad message state in interrupt handler\n");

                /* Never fail */
                return IRQ_HANDLED;
        }

        return drv_data->transfer_handler(drv_data);
}

/*
 * The Quark SPI has an additional 24 bit register (DDS_CLK_RATE) to multiply
 * input frequency by fractions of 2^24. It also has a divider by 5.
 *
 * There are formulas to get baud rate value for given input frequency and
 * divider parameters, such as DDS_CLK_RATE and SCR:
 *
 * Fsys = 200MHz
 *
 * Fssp = Fsys * DDS_CLK_RATE / 2^24                    (1)
 * Baud rate = Fsclk = Fssp / (2 * (SCR + 1))           (2)
 *
 * DDS_CLK_RATE either 2^n or 2^n / 5.
 * SCR is in range 0 .. 255
 *
 * Divisor = 5^i * 2^j * 2 * k
 *       i = [0, 1]      i = 1 iff j = 0 or j > 3
 *       j = [0, 23]     j = 0 iff i = 1
 *       k = [1, 256]
 * Special case: j = 0, i = 1: Divisor = 2 / 5
 *
 * Accordingly to the specification the recommended values for DDS_CLK_RATE
 * are:
 *      Case 1:         2^n, n = [0, 23]
 *      Case 2:         2^24 * 2 / 5 (0x666666)
 *      Case 3:         less than or equal to 2^24 / 5 / 16 (0x33333)
 *
 * In all cases the lowest possible value is better.
 *
 * The function calculates parameters for all cases and chooses the one closest
 * to the asked baud rate.
 */
static unsigned int quark_x1000_get_clk_div(int rate, u32 *dds)
{
        unsigned long xtal = 200000000;
        unsigned long fref = xtal / 2;          /* mandatory division by 2,
                                                   see (2) */
                                                /* case 3 */
        unsigned long fref1 = fref / 2;         /* case 1 */
        unsigned long fref2 = fref * 2 / 5;     /* case 2 */
        unsigned long scale;
        unsigned long q, q1, q2;
        long r, r1, r2;
        u32 mul;

        /* Case 1 */

        /* Set initial value for DDS_CLK_RATE */
        mul = (1 << 24) >> 1;

        /* Calculate initial quot */
        q1 = DIV_ROUND_UP(fref1, rate);

        /* Scale q1 if it's too big */
        if (q1 > 256) {
                /* Scale q1 to range [1, 512] */
                scale = fls_long(q1 - 1);
                if (scale > 9) {
                        q1 >>= scale - 9;
                        mul >>= scale - 9;
                }

                /* Round the result if we have a remainder */
                q1 += q1 & 1;
        }

        /* Decrease DDS_CLK_RATE as much as we can without loss in precision */
        scale = __ffs(q1);
        q1 >>= scale;
        mul >>= scale;

        /* Get the remainder */
        r1 = abs(fref1 / (1 << (24 - fls_long(mul))) / q1 - rate);

        /* Case 2 */

        q2 = DIV_ROUND_UP(fref2, rate);
        r2 = abs(fref2 / q2 - rate);

        /*
         * Choose the best between two: less remainder we have the better. We
         * can't go case 2 if q2 is greater than 256 since SCR register can
         * hold only values 0 .. 255.
         */
        if (r2 >= r1 || q2 > 256) {
                /* case 1 is better */
                r = r1;
                q = q1;
        } else {
                /* case 2 is better */
                r = r2;
                q = q2;
                mul = (1 << 24) * 2 / 5;
        }

        /* Check case 3 only if the divisor is big enough */
        if (fref / rate >= 80) {
                u64 fssp;
                u32 m;

                /* Calculate initial quot */
                q1 = DIV_ROUND_UP(fref, rate);
                m = (1 << 24) / q1;

                /* Get the remainder */
                fssp = (u64)fref * m;
                do_div(fssp, 1 << 24);
                r1 = abs(fssp - rate);

                /* Choose this one if it suits better */
                if (r1 < r) {
                        /* case 3 is better */
                        q = 1;
                        mul = m;
                }
        }

        *dds = mul;
        return q - 1;
}

static unsigned int ssp_get_clk_div(struct driver_data *drv_data, int rate)
{
        unsigned long ssp_clk = drv_data->master->max_speed_hz;
        const struct ssp_device *ssp = drv_data->ssp;

        rate = min_t(int, ssp_clk, rate);

        if (ssp->type == PXA25x_SSP || ssp->type == CE4100_SSP)
                return (ssp_clk / (2 * rate) - 1) & 0xff;
        else
                return (ssp_clk / rate - 1) & 0xfff;
}

static unsigned int pxa2xx_ssp_get_clk_div(struct driver_data *drv_data,
                                           int rate)
{
        struct chip_data *chip =
                spi_get_ctldata(drv_data->master->cur_msg->spi);
        unsigned int clk_div;

        switch (drv_data->ssp_type) {
        case QUARK_X1000_SSP:
                clk_div = quark_x1000_get_clk_div(rate, &chip->dds_rate);
                break;
        default:
                clk_div = ssp_get_clk_div(drv_data, rate);
                break;
        }
        return clk_div << 8;
}

static bool pxa2xx_spi_can_dma(struct spi_master *master,
                               struct spi_device *spi,
                               struct spi_transfer *xfer)
{
        struct chip_data *chip = spi_get_ctldata(spi);

        return chip->enable_dma &&
               xfer->len <= MAX_DMA_LEN &&
               xfer->len >= chip->dma_burst_size;
}

static void pump_transfers(unsigned long data)
{
        struct driver_data *drv_data = (struct driver_data *)data;
        struct spi_master *master = drv_data->master;
        struct spi_message *message = master->cur_msg;
        struct chip_data *chip = spi_get_ctldata(message->spi);
        u32 dma_thresh = chip->dma_threshold;
        u32 dma_burst = chip->dma_burst_size;
        u32 change_mask = pxa2xx_spi_get_ssrc1_change_mask(drv_data);
        struct spi_transfer *transfer;
        struct spi_transfer *previous;
        u32 clk_div;
        u8 bits;
        u32 speed;
        u32 cr0;
        u32 cr1;
        int err;
        int dma_mapped;

        /* Get current state information */
        transfer = drv_data->cur_transfer;

        /* Handle for abort */
        if (message->state == ERROR_STATE) {
                message->status = -EIO;
                giveback(drv_data);
                return;
        }

        /* Handle end of message */
        if (message->state == DONE_STATE) {
                message->status = 0;
                giveback(drv_data);
                return;
        }

        /* Delay if requested at end of transfer before CS change */
        if (message->state == RUNNING_STATE) {
                previous = list_entry(transfer->transfer_list.prev,
                                        struct spi_transfer,
                                        transfer_list);
                if (previous->delay_usecs)

                        udelay(previous->delay_usecs);

                /* Drop chip select only if cs_change is requested */
                if (previous->cs_change)
                        cs_deassert(drv_data);
        }

        /* Check if we can DMA this transfer */
        if (transfer->len > MAX_DMA_LEN && chip->enable_dma) {

                /* reject already-mapped transfers; PIO won't always work */
                if (message->is_dma_mapped
                                || transfer->rx_dma || transfer->tx_dma) {
                        dev_err(&drv_data->pdev->dev,
                                "pump_transfers: mapped transfer length of "
                                "%u is greater than %d\n",
                                transfer->len, MAX_DMA_LEN);
                        message->status = -EINVAL;
                        giveback(drv_data);
                        return;
                }

                /* warn ... we force this to PIO mode */
                dev_warn_ratelimited(&message->spi->dev,
                                     "pump_transfers: DMA disabled for transfer length %ld "
                                     "greater than %d\n",
                                     (long)drv_data->len, MAX_DMA_LEN);
        }

        /* Setup the transfer state based on the type of transfer */
        if (pxa2xx_spi_flush(drv_data) == 0) {
                dev_err(&drv_data->pdev->dev, "pump_transfers: flush failed\n");
                message->status = -EIO;
                giveback(drv_data);
                return;
        }
        drv_data->n_bytes = chip->n_bytes;
        drv_data->tx = (void *)transfer->tx_buf;
        drv_data->tx_end = drv_data->tx + transfer->len;
        drv_data->rx = transfer->rx_buf;
        drv_data->rx_end = drv_data->rx + transfer->len;
        drv_data->len = transfer->len;
        drv_data->write = drv_data->tx ? chip->write : null_writer;
        drv_data->read = drv_data->rx ? chip->read : null_reader;

        /* Change speed and bit per word on a per transfer */
        bits = transfer->bits_per_word;
        speed = transfer->speed_hz;

        clk_div = pxa2xx_ssp_get_clk_div(drv_data, speed);

        if (bits <= 8) {
                drv_data->n_bytes = 1;
                drv_data->read = drv_data->read != null_reader ?
                                        u8_reader : null_reader;
                drv_data->write = drv_data->write != null_writer ?
                                        u8_writer : null_writer;
        } else if (bits <= 16) {
                drv_data->n_bytes = 2;
                drv_data->read = drv_data->read != null_reader ?
                                        u16_reader : null_reader;
                drv_data->write = drv_data->write != null_writer ?
                                        u16_writer : null_writer;
        } else if (bits <= 32) {
                drv_data->n_bytes = 4;
                drv_data->read = drv_data->read != null_reader ?
                                        u32_reader : null_reader;
                drv_data->write = drv_data->write != null_writer ?
                                        u32_writer : null_writer;
        }
        /*
         * if bits/word is changed in dma mode, then must check the
         * thresholds and burst also
         */
        if (chip->enable_dma) {
                if (pxa2xx_spi_set_dma_burst_and_threshold(chip,
                                                message->spi,
                                                bits, &dma_burst,
                                                &dma_thresh))
                        dev_warn_ratelimited(&message->spi->dev,
                                             "pump_transfers: DMA burst size reduced to match bits_per_word\n");
        }

        message->state = RUNNING_STATE;

        dma_mapped = master->can_dma &&
                     master->can_dma(master, message->spi, transfer) &&
                     master->cur_msg_mapped;
        if (dma_mapped) {

                /* Ensure we have the correct interrupt handler */
                drv_data->transfer_handler = pxa2xx_spi_dma_transfer;

                err = pxa2xx_spi_dma_prepare(drv_data, dma_burst);
                if (err) {
                        message->status = err;
                        giveback(drv_data);
                        return;
                }

                /* Clear status and start DMA engine */
                cr1 = chip->cr1 | dma_thresh | drv_data->dma_cr1;
                pxa2xx_spi_write(drv_data, SSSR, drv_data->clear_sr);

                pxa2xx_spi_dma_start(drv_data);
        } else {
                /* Ensure we have the correct interrupt handler */
                drv_data->transfer_handler = interrupt_transfer;

                /* Clear status  */
                cr1 = chip->cr1 | chip->threshold | drv_data->int_cr1;
                write_SSSR_CS(drv_data, drv_data->clear_sr);
        }

        /* NOTE:  PXA25x_SSP _could_ use external clocking ... */
        cr0 = pxa2xx_configure_sscr0(drv_data, clk_div, bits);
        if (!pxa25x_ssp_comp(drv_data))
                dev_dbg(&message->spi->dev, "%u Hz actual, %s\n",
                        master->max_speed_hz
                                / (1 + ((cr0 & SSCR0_SCR(0xfff)) >> 8)),
                        dma_mapped ? "DMA" : "PIO");
        else
                dev_dbg(&message->spi->dev, "%u Hz actual, %s\n",
                        master->max_speed_hz / 2
                                / (1 + ((cr0 & SSCR0_SCR(0x0ff)) >> 8)),
                        dma_mapped ? "DMA" : "PIO");

        if (is_lpss_ssp(drv_data)) {
                if ((pxa2xx_spi_read(drv_data, SSIRF) & 0xff)
                    != chip->lpss_rx_threshold)
                        pxa2xx_spi_write(drv_data, SSIRF,
                                         chip->lpss_rx_threshold);
                if ((pxa2xx_spi_read(drv_data, SSITF) & 0xffff)
                    != chip->lpss_tx_threshold)
                        pxa2xx_spi_write(drv_data, SSITF,
                                         chip->lpss_tx_threshold);
        }

        if (is_quark_x1000_ssp(drv_data) &&
            (pxa2xx_spi_read(drv_data, DDS_RATE) != chip->dds_rate))
                pxa2xx_spi_write(drv_data, DDS_RATE, chip->dds_rate);

        /* see if we need to reload the config registers */
        if ((pxa2xx_spi_read(drv_data, SSCR0) != cr0)
            || (pxa2xx_spi_read(drv_data, SSCR1) & change_mask)
            != (cr1 & change_mask)) {
                /* stop the SSP, and update the other bits */
                pxa2xx_spi_write(drv_data, SSCR0, cr0 & ~SSCR0_SSE);
                if (!pxa25x_ssp_comp(drv_data))
                        pxa2xx_spi_write(drv_data, SSTO, chip->timeout);
                /* first set CR1 without interrupt and service enables */
                pxa2xx_spi_write(drv_data, SSCR1, cr1 & change_mask);
                /* restart the SSP */
                pxa2xx_spi_write(drv_data, SSCR0, cr0);

        } else {
                if (!pxa25x_ssp_comp(drv_data))
                        pxa2xx_spi_write(drv_data, SSTO, chip->timeout);
        }

        cs_assert(drv_data);

        /* after chip select, release the data by enabling service
         * requests and interrupts, without changing any mode bits */
        pxa2xx_spi_write(drv_data, SSCR1, cr1);
}

static int pxa2xx_spi_transfer_one_message(struct spi_master *master,
                                           struct spi_message *msg)
{
        struct driver_data *drv_data = spi_master_get_devdata(master);

        /* Initial message state*/
        msg->state = START_STATE;
        drv_data->cur_transfer = list_entry(msg->transfers.next,
                                                struct spi_transfer,
                                                transfer_list);

        /* Mark as busy and launch transfers */
        tasklet_schedule(&drv_data->pump_transfers);
        return 0;
}

static int pxa2xx_spi_unprepare_transfer(struct spi_master *master)
{
        struct driver_data *drv_data = spi_master_get_devdata(master);

        /* Disable the SSP now */
        pxa2xx_spi_write(drv_data, SSCR0,
                         pxa2xx_spi_read(drv_data, SSCR0) & ~SSCR0_SSE);

        return 0;
}

static int setup_cs(struct spi_device *spi, struct chip_data *chip,
                    struct pxa2xx_spi_chip *chip_info)
{
        struct driver_data *drv_data = spi_master_get_devdata(spi->master);
        int err = 0;

        if (chip == NULL)
                return 0;

        if (drv_data->cs_gpiods) {
                struct gpio_desc *gpiod;

                gpiod = drv_data->cs_gpiods[spi->chip_select];
                if (gpiod) {
                        chip->gpio_cs = desc_to_gpio(gpiod);
                        chip->gpio_cs_inverted = spi->mode & SPI_CS_HIGH;
                        gpiod_set_value(gpiod, chip->gpio_cs_inverted);
                }

                return 0;
        }

        if (chip_info == NULL)
                return 0;

        /* NOTE: setup() can be called multiple times, possibly with
         * different chip_info, release previously requested GPIO
         */
        if (gpio_is_valid(chip->gpio_cs))
                gpio_free(chip->gpio_cs);

        /* If (*cs_control) is provided, ignore GPIO chip select */
        if (chip_info->cs_control) {
                chip->cs_control = chip_info->cs_control;
                return 0;
        }

        if (gpio_is_valid(chip_info->gpio_cs)) {
                err = gpio_request(chip_info->gpio_cs, "SPI_CS");
                if (err) {
                        dev_err(&spi->dev, "failed to request chip select GPIO%d\n",
                                chip_info->gpio_cs);
                        return err;
                }

                chip->gpio_cs = chip_info->gpio_cs;
                chip->gpio_cs_inverted = spi->mode & SPI_CS_HIGH;

                err = gpio_direction_output(chip->gpio_cs,
                                        !chip->gpio_cs_inverted);
        }

        return err;
}

static int setup(struct spi_device *spi)
{
        struct pxa2xx_spi_chip *chip_info;
        struct chip_data *chip;
        const struct lpss_config *config;
        struct driver_data *drv_data = spi_master_get_devdata(spi->master);
        uint tx_thres, tx_hi_thres, rx_thres;

        switch (drv_data->ssp_type) {
        case QUARK_X1000_SSP:
                tx_thres = TX_THRESH_QUARK_X1000_DFLT;
                tx_hi_thres = 0;
                rx_thres = RX_THRESH_QUARK_X1000_DFLT;
                break;
        case CE4100_SSP:
                tx_thres = TX_THRESH_CE4100_DFLT;
                tx_hi_thres = 0;
                rx_thres = RX_THRESH_CE4100_DFLT;
                break;
        case LPSS_LPT_SSP:
        case LPSS_BYT_SSP:
        case LPSS_BSW_SSP:
        case LPSS_SPT_SSP:
        case LPSS_BXT_SSP:
                config = lpss_get_config(drv_data);
                tx_thres = config->tx_threshold_lo;
                tx_hi_thres = config->tx_threshold_hi;
                rx_thres = config->rx_threshold;
                break;
        default:
                tx_thres = TX_THRESH_DFLT;
                tx_hi_thres = 0;
                rx_thres = RX_THRESH_DFLT;
                break;
        }

        /* Only alloc on first setup */
        chip = spi_get_ctldata(spi);
        if (!chip) {
                chip = kzalloc(sizeof(struct chip_data), GFP_KERNEL);
                if (!chip)
                        return -ENOMEM;

                if (drv_data->ssp_type == CE4100_SSP) {
                        if (spi->chip_select > 4) {
                                dev_err(&spi->dev,
                                        "failed setup: cs number must not be > 4.\n");
                                kfree(chip);
                                return -EINVAL;
                        }

                        chip->frm = spi->chip_select;
                } else
                        chip->gpio_cs = -1;
                chip->enable_dma = drv_data->master_info->enable_dma;
                chip->timeout = TIMOUT_DFLT;
        }

        /* protocol drivers may change the chip settings, so...
         * if chip_info exists, use it */
        chip_info = spi->controller_data;

        /* chip_info isn't always needed */
        chip->cr1 = 0;
        if (chip_info) {
                if (chip_info->timeout)
                        chip->timeout = chip_info->timeout;
                if (chip_info->tx_threshold)
                        tx_thres = chip_info->tx_threshold;
                if (chip_info->tx_hi_threshold)
                        tx_hi_thres = chip_info->tx_hi_threshold;
                if (chip_info->rx_threshold)
                        rx_thres = chip_info->rx_threshold;
                chip->dma_threshold = 0;
                if (chip_info->enable_loopback)
                        chip->cr1 = SSCR1_LBM;
        }

        chip->lpss_rx_threshold = SSIRF_RxThresh(rx_thres);
        chip->lpss_tx_threshold = SSITF_TxLoThresh(tx_thres)
                                | SSITF_TxHiThresh(tx_hi_thres);

        /* set dma burst and threshold outside of chip_info path so that if
         * chip_info goes away after setting chip->enable_dma, the
         * burst and threshold can still respond to changes in bits_per_word */
        if (chip->enable_dma) {
                /* set up legal burst and threshold for dma */
                if (pxa2xx_spi_set_dma_burst_and_threshold(chip, spi,
                                                spi->bits_per_word,
                                                &chip->dma_burst_size,
                                                &chip->dma_threshold)) {
                        dev_warn(&spi->dev,
                                 "in setup: DMA burst size reduced to match bits_per_word\n");
                }
        }

        switch (drv_data->ssp_type) {
        case QUARK_X1000_SSP:
                chip->threshold = (QUARK_X1000_SSCR1_RxTresh(rx_thres)
                                   & QUARK_X1000_SSCR1_RFT)
                                   | (QUARK_X1000_SSCR1_TxTresh(tx_thres)
                                   & QUARK_X1000_SSCR1_TFT);
                break;
        case CE4100_SSP:
                chip->threshold = (CE4100_SSCR1_RxTresh(rx_thres) & CE4100_SSCR1_RFT) |
                        (CE4100_SSCR1_TxTresh(tx_thres) & CE4100_SSCR1_TFT);
                break;
        default:
                chip->threshold = (SSCR1_RxTresh(rx_thres) & SSCR1_RFT) |
                        (SSCR1_TxTresh(tx_thres) & SSCR1_TFT);
                break;
        }

        chip->cr1 &= ~(SSCR1_SPO | SSCR1_SPH);
        chip->cr1 |= (((spi->mode & SPI_CPHA) != 0) ? SSCR1_SPH : 0)
                        | (((spi->mode & SPI_CPOL) != 0) ? SSCR1_SPO : 0);

        if (spi->mode & SPI_LOOP)
                chip->cr1 |= SSCR1_LBM;

        if (spi->bits_per_word <= 8) {
                chip->n_bytes = 1;
                chip->read = u8_reader;
                chip->write = u8_writer;
        } else if (spi->bits_per_word <= 16) {
                chip->n_bytes = 2;
                chip->read = u16_reader;
                chip->write = u16_writer;
        } else if (spi->bits_per_word <= 32) {
                chip->n_bytes = 4;
                chip->read = u32_reader;
                chip->write = u32_writer;
        }

        spi_set_ctldata(spi, chip);

        if (drv_data->ssp_type == CE4100_SSP)
                return 0;

        return setup_cs(spi, chip, chip_info);
}

static void cleanup(struct spi_device *spi)
{
        struct chip_data *chip = spi_get_ctldata(spi);
        struct driver_data *drv_data = spi_master_get_devdata(spi->master);

        if (!chip)
                return;

        if (drv_data->ssp_type != CE4100_SSP && !drv_data->cs_gpiods &&
            gpio_is_valid(chip->gpio_cs))
                gpio_free(chip->gpio_cs);

        kfree(chip);
}

#ifdef CONFIG_PCI
#ifdef CONFIG_ACPI

static const struct acpi_device_id pxa2xx_spi_acpi_match[] = {
        { "INT33C0", LPSS_LPT_SSP },
        { "INT33C1", LPSS_LPT_SSP },
        { "INT3430", LPSS_LPT_SSP },
        { "INT3431", LPSS_LPT_SSP },
        { "80860F0E", LPSS_BYT_SSP },
        { "8086228E", LPSS_BSW_SSP },
        { },
};
MODULE_DEVICE_TABLE(acpi, pxa2xx_spi_acpi_match);

static int pxa2xx_spi_get_port_id(struct acpi_device *adev)
{
        unsigned int devid;
        int port_id = -1;

        if (adev && adev->pnp.unique_id &&
            !kstrtouint(adev->pnp.unique_id, 0, &devid))
                port_id = devid;
        return port_id;
}
#else /* !CONFIG_ACPI */
static int pxa2xx_spi_get_port_id(struct acpi_device *adev)
{
        return -1;
}
#endif

/*
 * PCI IDs of compound devices that integrate both host controller and private
 * integrated DMA engine. Please note these are not used in module
 * autoloading and probing in this module but matching the LPSS SSP type.
 */
static const struct pci_device_id pxa2xx_spi_pci_compound_match[] = {
        /* SPT-LP */
        { PCI_VDEVICE(INTEL, 0x9d29), LPSS_SPT_SSP },
        { PCI_VDEVICE(INTEL, 0x9d2a), LPSS_SPT_SSP },
        /* SPT-H */
        { PCI_VDEVICE(INTEL, 0xa129), LPSS_SPT_SSP },
        { PCI_VDEVICE(INTEL, 0xa12a), LPSS_SPT_SSP },
        /* KBL-H */
        { PCI_VDEVICE(INTEL, 0xa2a9), LPSS_SPT_SSP },
        { PCI_VDEVICE(INTEL, 0xa2aa), LPSS_SPT_SSP },
        /* BXT A-Step */
        { PCI_VDEVICE(INTEL, 0x0ac2), LPSS_BXT_SSP },
        { PCI_VDEVICE(INTEL, 0x0ac4), LPSS_BXT_SSP },
        { PCI_VDEVICE(INTEL, 0x0ac6), LPSS_BXT_SSP },
        /* BXT B-Step */
        { PCI_VDEVICE(INTEL, 0x1ac2), LPSS_BXT_SSP },
        { PCI_VDEVICE(INTEL, 0x1ac4), LPSS_BXT_SSP },
        { PCI_VDEVICE(INTEL, 0x1ac6), LPSS_BXT_SSP },
        /* APL */
        { PCI_VDEVICE(INTEL, 0x5ac2), LPSS_BXT_SSP },
        { PCI_VDEVICE(INTEL, 0x5ac4), LPSS_BXT_SSP },
        { PCI_VDEVICE(INTEL, 0x5ac6), LPSS_BXT_SSP },
        { },
};

static bool pxa2xx_spi_idma_filter(struct dma_chan *chan, void *param)
{
        struct device *dev = param;

        if (dev != chan->device->dev->parent)
                return false;

        return true;
}

static struct pxa2xx_spi_master *
pxa2xx_spi_init_pdata(struct platform_device *pdev)
{
        struct pxa2xx_spi_master *pdata;
        struct acpi_device *adev;
        struct ssp_device *ssp;
        struct resource *res;
        const struct acpi_device_id *adev_id = NULL;
        const struct pci_device_id *pcidev_id = NULL;
        int type;

        adev = ACPI_COMPANION(&pdev->dev);

        if (dev_is_pci(pdev->dev.parent))
                pcidev_id = pci_match_id(pxa2xx_spi_pci_compound_match,
                                         to_pci_dev(pdev->dev.parent));
        else if (adev)
                adev_id = acpi_match_device(pdev->dev.driver->acpi_match_table,
                                            &pdev->dev);
        else
                return NULL;

        if (adev_id)
                type = (int)adev_id->driver_data;
        else if (pcidev_id)
                type = (int)pcidev_id->driver_data;
        else
                return NULL;

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

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res)
                return NULL;

        ssp = &pdata->ssp;

        ssp->phys_base = res->start;
        ssp->mmio_base = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(ssp->mmio_base))
                return NULL;

        if (pcidev_id) {
                pdata->tx_param = pdev->dev.parent;
                pdata->rx_param = pdev->dev.parent;
                pdata->dma_filter = pxa2xx_spi_idma_filter;
        }

        ssp->clk = devm_clk_get(&pdev->dev, NULL);
        ssp->irq = platform_get_irq(pdev, 0);
        ssp->type = type;
        ssp->pdev = pdev;
        ssp->port_id = pxa2xx_spi_get_port_id(adev);

        pdata->num_chipselect = 1;
        pdata->enable_dma = true;

        return pdata;
}

#else /* !CONFIG_PCI */
static inline struct pxa2xx_spi_master *
pxa2xx_spi_init_pdata(struct platform_device *pdev)
{
        return NULL;
}
#endif

static int pxa2xx_spi_fw_translate_cs(struct spi_master *master, unsigned cs)
{
        struct driver_data *drv_data = spi_master_get_devdata(master);

        if (has_acpi_companion(&drv_data->pdev->dev)) {
                switch (drv_data->ssp_type) {
                /*
                 * For Atoms the ACPI DeviceSelection used by the Windows
                 * driver starts from 1 instead of 0 so translate it here
                 * to match what Linux expects.
                 */
                case LPSS_BYT_SSP:
                case LPSS_BSW_SSP:
                        return cs - 1;

                default:
                        break;
                }
        }

        return cs;
}

static int pxa2xx_spi_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct pxa2xx_spi_master *platform_info;
        struct spi_master *master;
        struct driver_data *drv_data;
        struct ssp_device *ssp;
        const struct lpss_config *config;
        int status, count;
        u32 tmp;

        platform_info = dev_get_platdata(dev);
        if (!platform_info) {
                platform_info = pxa2xx_spi_init_pdata(pdev);
                if (!platform_info) {
                        dev_err(&pdev->dev, "missing platform data\n");
                        return -ENODEV;
                }
        }

        ssp = pxa_ssp_request(pdev->id, pdev->name);
        if (!ssp)
                ssp = &platform_info->ssp;

        if (!ssp->mmio_base) {
                dev_err(&pdev->dev, "failed to get ssp\n");
                return -ENODEV;
        }

        master = spi_alloc_master(dev, sizeof(struct driver_data));
        if (!master) {
                dev_err(&pdev->dev, "cannot alloc spi_master\n");
                pxa_ssp_free(ssp);
                return -ENOMEM;
        }
        drv_data = spi_master_get_devdata(master);
        drv_data->master = master;
        drv_data->master_info = platform_info;
        drv_data->pdev = pdev;
        drv_data->ssp = ssp;

        master->dev.of_node = pdev->dev.of_node;
        /* the spi->mode bits understood by this driver: */
        master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LOOP;

        master->bus_num = ssp->port_id;
        master->dma_alignment = DMA_ALIGNMENT;
        master->cleanup = cleanup;
        master->setup = setup;
        master->transfer_one_message = pxa2xx_spi_transfer_one_message;
        master->unprepare_transfer_hardware = pxa2xx_spi_unprepare_transfer;
        master->fw_translate_cs = pxa2xx_spi_fw_translate_cs;
        master->auto_runtime_pm = true;
        master->flags = SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX;

        drv_data->ssp_type = ssp->type;

        drv_data->ioaddr = ssp->mmio_base;
        drv_data->ssdr_physical = ssp->phys_base + SSDR;
        if (pxa25x_ssp_comp(drv_data)) {
                switch (drv_data->ssp_type) {
                case QUARK_X1000_SSP:
                        master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
                        break;
                default:
                        master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
                        break;
                }

                drv_data->int_cr1 = SSCR1_TIE | SSCR1_RIE;
                drv_data->dma_cr1 = 0;
                drv_data->clear_sr = SSSR_ROR;
                drv_data->mask_sr = SSSR_RFS | SSSR_TFS | SSSR_ROR;
        } else {
                master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
                drv_data->int_cr1 = SSCR1_TIE | SSCR1_RIE | SSCR1_TINTE;
                drv_data->dma_cr1 = DEFAULT_DMA_CR1;
                drv_data->clear_sr = SSSR_ROR | SSSR_TINT;
                drv_data->mask_sr = SSSR_TINT | SSSR_RFS | SSSR_TFS | SSSR_ROR;
        }

        status = request_irq(ssp->irq, ssp_int, IRQF_SHARED, dev_name(dev),
                        drv_data);
        if (status < 0) {
                dev_err(&pdev->dev, "cannot get IRQ %d\n", ssp->irq);
                goto out_error_master_alloc;
        }

        /* Setup DMA if requested */
        if (platform_info->enable_dma) {
                status = pxa2xx_spi_dma_setup(drv_data);
                if (status) {
                        dev_dbg(dev, "no DMA channels available, using PIO\n");
                        platform_info->enable_dma = false;
                } else {
                        master->can_dma = pxa2xx_spi_can_dma;
                }
        }

        /* Enable SOC clock */
        clk_prepare_enable(ssp->clk);

        master->max_speed_hz = clk_get_rate(ssp->clk);

        /* Load default SSP configuration */
        pxa2xx_spi_write(drv_data, SSCR0, 0);
        switch (drv_data->ssp_type) {
        case QUARK_X1000_SSP:
                tmp = QUARK_X1000_SSCR1_RxTresh(RX_THRESH_QUARK_X1000_DFLT) |
                      QUARK_X1000_SSCR1_TxTresh(TX_THRESH_QUARK_X1000_DFLT);
                pxa2xx_spi_write(drv_data, SSCR1, tmp);

                /* using the Motorola SPI protocol and use 8 bit frame */
                tmp = QUARK_X1000_SSCR0_Motorola | QUARK_X1000_SSCR0_DataSize(8);
                pxa2xx_spi_write(drv_data, SSCR0, tmp);
                break;
        case CE4100_SSP:
                tmp = CE4100_SSCR1_RxTresh(RX_THRESH_CE4100_DFLT) |
                      CE4100_SSCR1_TxTresh(TX_THRESH_CE4100_DFLT);
                pxa2xx_spi_write(drv_data, SSCR1, tmp);
                tmp = SSCR0_SCR(2) | SSCR0_Motorola | SSCR0_DataSize(8);
                pxa2xx_spi_write(drv_data, SSCR0, tmp);
        default:
                tmp = SSCR1_RxTresh(RX_THRESH_DFLT) |
                      SSCR1_TxTresh(TX_THRESH_DFLT);
                pxa2xx_spi_write(drv_data, SSCR1, tmp);
                tmp = SSCR0_SCR(2) | SSCR0_Motorola | SSCR0_DataSize(8);
                pxa2xx_spi_write(drv_data, SSCR0, tmp);
                break;
        }

        if (!pxa25x_ssp_comp(drv_data))
                pxa2xx_spi_write(drv_data, SSTO, 0);

        if (!is_quark_x1000_ssp(drv_data))
                pxa2xx_spi_write(drv_data, SSPSP, 0);

        if (is_lpss_ssp(drv_data)) {
                lpss_ssp_setup(drv_data);
                config = lpss_get_config(drv_data);
                if (config->reg_capabilities >= 0) {
                        tmp = __lpss_ssp_read_priv(drv_data,
                                                   config->reg_capabilities);
                        tmp &= LPSS_CAPS_CS_EN_MASK;
                        tmp >>= LPSS_CAPS_CS_EN_SHIFT;
                        platform_info->num_chipselect = ffz(tmp);
                } else if (config->cs_num) {
                        platform_info->num_chipselect = config->cs_num;
                }
        }
        master->num_chipselect = platform_info->num_chipselect;

        count = gpiod_count(&pdev->dev, "cs");
        if (count > 0) {
                int i;

                master->num_chipselect = max_t(int, count,
                        master->num_chipselect);

                drv_data->cs_gpiods = devm_kcalloc(&pdev->dev,
                        master->num_chipselect, sizeof(struct gpio_desc *),
                        GFP_KERNEL);
                if (!drv_data->cs_gpiods) {
                        status = -ENOMEM;
                        goto out_error_clock_enabled;
                }

                for (i = 0; i < master->num_chipselect; i++) {
                        struct gpio_desc *gpiod;

                        gpiod = devm_gpiod_get_index(dev, "cs", i,
                                                     GPIOD_OUT_HIGH);
                        if (IS_ERR(gpiod)) {
                                /* Means use native chip select */
                                if (PTR_ERR(gpiod) == -ENOENT)
                                        continue;

                                status = (int)PTR_ERR(gpiod);
                                goto out_error_clock_enabled;
                        } else {
                                drv_data->cs_gpiods[i] = gpiod;
                        }
                }
        }

        tasklet_init(&drv_data->pump_transfers, pump_transfers,
                     (unsigned long)drv_data);

        pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
        pm_runtime_use_autosuspend(&pdev->dev);
        pm_runtime_set_active(&pdev->dev);
        pm_runtime_enable(&pdev->dev);

        /* Register with the SPI framework */
        platform_set_drvdata(pdev, drv_data);
        status = devm_spi_register_master(&pdev->dev, master);
        if (status != 0) {
                dev_err(&pdev->dev, "problem registering spi master\n");
                goto out_error_clock_enabled;
        }

        return status;

out_error_clock_enabled:
        clk_disable_unprepare(ssp->clk);
        pxa2xx_spi_dma_release(drv_data);
        free_irq(ssp->irq, drv_data);

out_error_master_alloc:
        spi_master_put(master);
        pxa_ssp_free(ssp);
        return status;
}

static int pxa2xx_spi_remove(struct platform_device *pdev)
{
        struct driver_data *drv_data = platform_get_drvdata(pdev);
        struct ssp_device *ssp;

        if (!drv_data)
                return 0;
        ssp = drv_data->ssp;

        pm_runtime_get_sync(&pdev->dev);

        /* Disable the SSP at the peripheral and SOC level */
        pxa2xx_spi_write(drv_data, SSCR0, 0);
        clk_disable_unprepare(ssp->clk);

        /* Release DMA */
        if (drv_data->master_info->enable_dma)
                pxa2xx_spi_dma_release(drv_data);

        pm_runtime_put_noidle(&pdev->dev);
        pm_runtime_disable(&pdev->dev);

        /* Release IRQ */
        free_irq(ssp->irq, drv_data);

        /* Release SSP */
        pxa_ssp_free(ssp);

        return 0;
}

static void pxa2xx_spi_shutdown(struct platform_device *pdev)
{
        int status = 0;

        if ((status = pxa2xx_spi_remove(pdev)) != 0)
                dev_err(&pdev->dev, "shutdown failed with %d\n", status);
}

#ifdef CONFIG_PM_SLEEP
static int pxa2xx_spi_suspend(struct device *dev)
{
        struct driver_data *drv_data = dev_get_drvdata(dev);
        struct ssp_device *ssp = drv_data->ssp;
        int status;

        status = spi_master_suspend(drv_data->master);
        if (status != 0)
                return status;
        pxa2xx_spi_write(drv_data, SSCR0, 0);

        if (!pm_runtime_suspended(dev))
                clk_disable_unprepare(ssp->clk);

        return 0;
}

static int pxa2xx_spi_resume(struct device *dev)
{
        struct driver_data *drv_data = dev_get_drvdata(dev);
        struct ssp_device *ssp = drv_data->ssp;
        int status;

        /* Enable the SSP clock */
        if (!pm_runtime_suspended(dev))
                clk_prepare_enable(ssp->clk);

        /* Restore LPSS private register bits */
        if (is_lpss_ssp(drv_data))
                lpss_ssp_setup(drv_data);

        /* Start the queue running */
        status = spi_master_resume(drv_data->master);
        if (status != 0) {
                dev_err(dev, "problem starting queue (%d)\n", status);
                return status;
        }

        return 0;
}
#endif

#ifdef CONFIG_PM
static int pxa2xx_spi_runtime_suspend(struct device *dev)
{
        struct driver_data *drv_data = dev_get_drvdata(dev);

        clk_disable_unprepare(drv_data->ssp->clk);
        return 0;
}

static int pxa2xx_spi_runtime_resume(struct device *dev)
{
        struct driver_data *drv_data = dev_get_drvdata(dev);

        clk_prepare_enable(drv_data->ssp->clk);
        return 0;
}
#endif

static const struct dev_pm_ops pxa2xx_spi_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(pxa2xx_spi_suspend, pxa2xx_spi_resume)
        SET_RUNTIME_PM_OPS(pxa2xx_spi_runtime_suspend,
                           pxa2xx_spi_runtime_resume, NULL)
};

static struct platform_driver driver = {
        .driver = {
                .name   = "pxa2xx-spi",
                .pm     = &pxa2xx_spi_pm_ops,
                .acpi_match_table = ACPI_PTR(pxa2xx_spi_acpi_match),
        },
        .probe = pxa2xx_spi_probe,
        .remove = pxa2xx_spi_remove,
        .shutdown = pxa2xx_spi_shutdown,
};

static int __init pxa2xx_spi_init(void)
{
        return platform_driver_register(&driver);
}
subsys_initcall(pxa2xx_spi_init);

static void __exit pxa2xx_spi_exit(void)
{
        platform_driver_unregister(&driver);
}
module_exit(pxa2xx_spi_exit);