drivers/spi/pxa2xx_spi.c

/*
 * Copyright (C) 2005 Stephen Street / StreetFire Sound Labs
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/ioport.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/spi/spi.h>
#include <linux/workqueue.h>
#include <linux/errno.h>
#include <linux/delay.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/hardware.h>
#include <asm/delay.h>
#include <asm/dma.h>

#include <asm/arch/hardware.h>
#include <asm/arch/pxa-regs.h>
#include <asm/arch/pxa2xx_spi.h>

MODULE_AUTHOR("Stephen Street");
MODULE_DESCRIPTION("PXA2xx SSP SPI Contoller");
MODULE_LICENSE("GPL");

#define MAX_BUSES 3

#define DMA_INT_MASK (DCSR_ENDINTR | DCSR_STARTINTR | DCSR_BUSERR)
#define RESET_DMA_CHANNEL (DCSR_NODESC | DMA_INT_MASK)
#define IS_DMA_ALIGNED(x) (((u32)(x)&0x07)==0)

#define DEFINE_SSP_REG(reg, off) \
static inline u32 read_##reg(void *p) { return __raw_readl(p + (off)); } \
static inline void write_##reg(u32 v, void *p) { __raw_writel(v, p + (off)); }

DEFINE_SSP_REG(SSCR0, 0x00)
DEFINE_SSP_REG(SSCR1, 0x04)
DEFINE_SSP_REG(SSSR, 0x08)
DEFINE_SSP_REG(SSITR, 0x0c)
DEFINE_SSP_REG(SSDR, 0x10)
DEFINE_SSP_REG(SSTO, 0x28)
DEFINE_SSP_REG(SSPSP, 0x2c)

#define START_STATE ((void*)0)
#define RUNNING_STATE ((void*)1)
#define DONE_STATE ((void*)2)
#define ERROR_STATE ((void*)-1)

#define QUEUE_RUNNING 0
#define QUEUE_STOPPED 1

struct driver_data {
	/* Driver model hookup */
	struct platform_device *pdev;

	/* SPI framework hookup */
	enum pxa_ssp_type ssp_type;
	struct spi_master *master;

	/* PXA hookup */
	struct pxa2xx_spi_master *master_info;

	/* DMA setup stuff */
	int rx_channel;
	int tx_channel;
	u32 *null_dma_buf;

	/* SSP register addresses */
	void *ioaddr;
	u32 ssdr_physical;

	/* SSP masks*/
	u32 dma_cr1;
	u32 int_cr1;
	u32 clear_sr;
	u32 mask_sr;

	/* Driver message queue */
	struct workqueue_struct	*workqueue;
	struct work_struct pump_messages;
	spinlock_t lock;
	struct list_head queue;
	int busy;
	int run;

	/* Message Transfer pump */
	struct tasklet_struct pump_transfers;

	/* Current message transfer state info */
	struct spi_message* cur_msg;
	struct spi_transfer* cur_transfer;
	struct chip_data *cur_chip;
	size_t len;
	void *tx;
	void *tx_end;
	void *rx;
	void *rx_end;
	int dma_mapped;
	dma_addr_t rx_dma;
	dma_addr_t tx_dma;
	size_t rx_map_len;
	size_t tx_map_len;
	int cs_change;
	void (*write)(struct driver_data *drv_data);
	void (*read)(struct driver_data *drv_data);
	irqreturn_t (*transfer_handler)(struct driver_data *drv_data);
	void (*cs_control)(u32 command);
};

struct chip_data {
	u32 cr0;
	u32 cr1;
	u32 to;
	u32 psp;
	u32 timeout;
	u8 n_bytes;
	u32 dma_width;
	u32 dma_burst_size;
	u32 threshold;
	u32 dma_threshold;
	u8 enable_dma;
	void (*write)(struct driver_data *drv_data);
	void (*read)(struct driver_data *drv_data);
	void (*cs_control)(u32 command);
};

static void pump_messages(void *data);

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

	void *reg = drv_data->ioaddr;

	do {
		while (read_SSSR(reg) & SSSR_RNE) {
			read_SSDR(reg);
		}
	} while ((read_SSSR(reg) & SSSR_BSY) && limit--);
	write_SSSR(SSSR_ROR, reg);

	return limit;
}

static void restore_state(struct driver_data *drv_data)
{
	void *reg = drv_data->ioaddr;

	/* Clear status and disable clock */
	write_SSSR(drv_data->clear_sr, reg);
	write_SSCR0(drv_data->cur_chip->cr0 & ~SSCR0_SSE, reg);

	/* Load the registers */
	write_SSCR1(drv_data->cur_chip->cr1, reg);
	write_SSCR0(drv_data->cur_chip->cr0, reg);
	if (drv_data->ssp_type != PXA25x_SSP) {
		write_SSTO(0, reg);
		write_SSPSP(drv_data->cur_chip->psp, reg);
	}
}

static void null_cs_control(u32 command)
{
}

static void null_writer(struct driver_data *drv_data)
{
	void *reg = drv_data->ioaddr;
	u8 n_bytes = drv_data->cur_chip->n_bytes;

	while ((read_SSSR(reg) & SSSR_TNF)
			&& (drv_data->tx < drv_data->tx_end)) {
		write_SSDR(0, reg);
		drv_data->tx += n_bytes;
	}
}

static void null_reader(struct driver_data *drv_data)
{
	void *reg = drv_data->ioaddr;
	u8 n_bytes = drv_data->cur_chip->n_bytes;

	while ((read_SSSR(reg) & SSSR_RNE)
			&& (drv_data->rx < drv_data->rx_end)) {
		read_SSDR(reg);
		drv_data->rx += n_bytes;
	}
}

static void u8_writer(struct driver_data *drv_data)
{
	void *reg = drv_data->ioaddr;

	while ((read_SSSR(reg) & SSSR_TNF)
			&& (drv_data->tx < drv_data->tx_end)) {
		write_SSDR(*(u8 *)(drv_data->tx), reg);
		++drv_data->tx;
	}
}

static void u8_reader(struct driver_data *drv_data)
{
	void *reg = drv_data->ioaddr;

	while ((read_SSSR(reg) & SSSR_RNE)
			&& (drv_data->rx < drv_data->rx_end)) {
		*(u8 *)(drv_data->rx) = read_SSDR(reg);
		++drv_data->rx;
	}
}

static void u16_writer(struct driver_data *drv_data)
{
	void *reg = drv_data->ioaddr;

	while ((read_SSSR(reg) & SSSR_TNF)
			&& (drv_data->tx < drv_data->tx_end)) {
		write_SSDR(*(u16 *)(drv_data->tx), reg);
		drv_data->tx += 2;
	}
}

static void u16_reader(struct driver_data *drv_data)
{
	void *reg = drv_data->ioaddr;

	while ((read_SSSR(reg) & SSSR_RNE)
			&& (drv_data->rx < drv_data->rx_end)) {
		*(u16 *)(drv_data->rx) = read_SSDR(reg);
		drv_data->rx += 2;
	}
}
static void u32_writer(struct driver_data *drv_data)
{
	void *reg = drv_data->ioaddr;

	while ((read_SSSR(reg) & SSSR_TNF)
			&& (drv_data->tx < drv_data->tx_end)) {
		write_SSDR(*(u16 *)(drv_data->tx), reg);
		drv_data->tx += 4;
	}
}

static void u32_reader(struct driver_data *drv_data)
{
	void *reg = drv_data->ioaddr;

	while ((read_SSSR(reg) & SSSR_RNE)
			&& (drv_data->rx < drv_data->rx_end)) {
		*(u32 *)(drv_data->rx) = read_SSDR(reg);
		drv_data->rx += 4;
	}
}

static void *next_transfer(struct driver_data *drv_data)
{
	struct spi_message *msg = drv_data->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;
}

static int map_dma_buffers(struct driver_data *drv_data)
{
	struct spi_message *msg = drv_data->cur_msg;
	struct device *dev = &msg->spi->dev;

	if (!drv_data->cur_chip->enable_dma)
		return 0;

	if (msg->is_dma_mapped)
		return  drv_data->rx_dma && drv_data->tx_dma;

	if (!IS_DMA_ALIGNED(drv_data->rx) || !IS_DMA_ALIGNED(drv_data->tx))
		return 0;

	/* Modify setup if rx buffer is null */
	if (drv_data->rx == NULL) {
		*drv_data->null_dma_buf = 0;
		drv_data->rx = drv_data->null_dma_buf;
		drv_data->rx_map_len = 4;
	} else
		drv_data->rx_map_len = drv_data->len;


	/* Modify setup if tx buffer is null */
	if (drv_data->tx == NULL) {
		*drv_data->null_dma_buf = 0;
		drv_data->tx = drv_data->null_dma_buf;
		drv_data->tx_map_len = 4;
	} else
		drv_data->tx_map_len = drv_data->len;

	/* Stream map the rx buffer */
	drv_data->rx_dma = dma_map_single(dev, drv_data->rx,
						drv_data->rx_map_len,
						DMA_FROM_DEVICE);
	if (dma_mapping_error(drv_data->rx_dma))
		return 0;

	/* Stream map the tx buffer */
	drv_data->tx_dma = dma_map_single(dev, drv_data->tx,
						drv_data->tx_map_len,
						DMA_TO_DEVICE);

	if (dma_mapping_error(drv_data->tx_dma)) {
		dma_unmap_single(dev, drv_data->rx_dma,
					drv_data->rx_map_len, DMA_FROM_DEVICE);
		return 0;
	}

	return 1;
}

static void unmap_dma_buffers(struct driver_data *drv_data)
{
	struct device *dev;

	if (!drv_data->dma_mapped)
		return;

	if (!drv_data->cur_msg->is_dma_mapped) {
		dev = &drv_data->cur_msg->spi->dev;
		dma_unmap_single(dev, drv_data->rx_dma,
					drv_data->rx_map_len, DMA_FROM_DEVICE);
		dma_unmap_single(dev, drv_data->tx_dma,
					drv_data->tx_map_len, DMA_TO_DEVICE);
	}

	drv_data->dma_mapped = 0;
}

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

	last_transfer = list_entry(message->transfers.prev,
					struct spi_transfer,
					transfer_list);

	if (!last_transfer->cs_change)
		drv_data->cs_control(PXA2XX_CS_DEASSERT);

	message->state = NULL;
	if (message->complete)
		message->complete(message->context);

	drv_data->cur_msg = NULL;
	drv_data->cur_transfer = NULL;
	drv_data->cur_chip = NULL;
	queue_work(drv_data->workqueue, &drv_data->pump_messages);
}

static int wait_ssp_rx_stall(void *ioaddr)
{
	unsigned long limit = loops_per_jiffy << 1;

	while ((read_SSSR(ioaddr) & SSSR_BSY) && limit--)
		cpu_relax();

	return limit;
}

static int wait_dma_channel_stop(int channel)
{
	unsigned long limit = loops_per_jiffy << 1;

	while (!(DCSR(channel) & DCSR_STOPSTATE) && limit--)
		cpu_relax();

	return limit;
}

static void dma_handler(int channel, void *data, struct pt_regs *regs)
{
	struct driver_data *drv_data = data;
	struct spi_message *msg = drv_data->cur_msg;
	void *reg = drv_data->ioaddr;
	u32 irq_status = DCSR(channel) & DMA_INT_MASK;
	u32 trailing_sssr = 0;

	if (irq_status & DCSR_BUSERR) {

		/* Disable interrupts, clear status and reset DMA */
		if (drv_data->ssp_type != PXA25x_SSP)
			write_SSTO(0, reg);
		write_SSSR(drv_data->clear_sr, reg);
		write_SSCR1(read_SSCR1(reg) & ~drv_data->dma_cr1, reg);
		DCSR(drv_data->rx_channel) = RESET_DMA_CHANNEL;
		DCSR(drv_data->tx_channel) = RESET_DMA_CHANNEL;

		if (flush(drv_data) == 0)
			dev_err(&drv_data->pdev->dev,
					"dma_handler: flush fail\n");

		unmap_dma_buffers(drv_data);

		if (channel == drv_data->tx_channel)
			dev_err(&drv_data->pdev->dev,
				"dma_handler: bad bus address on "
				"tx channel %d, source %x target = %x\n",
				channel, DSADR(channel), DTADR(channel));
		else
			dev_err(&drv_data->pdev->dev,
				"dma_handler: bad bus address on "
				"rx channel %d, source %x target = %x\n",
				channel, DSADR(channel), DTADR(channel));

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

	/* PXA255x_SSP has no timeout interrupt, wait for tailing bytes */
	if ((drv_data->ssp_type == PXA25x_SSP)
		&& (channel == drv_data->tx_channel)
		&& (irq_status & DCSR_ENDINTR)) {

		/* Wait for rx to stall */
		if (wait_ssp_rx_stall(drv_data->ioaddr) == 0)
			dev_err(&drv_data->pdev->dev,
				"dma_handler: ssp rx stall failed\n");

		/* Clear and disable interrupts on SSP and DMA channels*/
		write_SSSR(drv_data->clear_sr, reg);
		write_SSCR1(read_SSCR1(reg) & ~drv_data->dma_cr1, reg);
		DCSR(drv_data->tx_channel) = RESET_DMA_CHANNEL;
		DCSR(drv_data->rx_channel) = RESET_DMA_CHANNEL;
		if (wait_dma_channel_stop(drv_data->rx_channel) == 0)
			dev_err(&drv_data->pdev->dev,
				"dma_handler: dma rx channel stop failed\n");

		unmap_dma_buffers(drv_data);

		/* Read trailing bytes */
		/* Calculate number of trailing bytes, read them */
		trailing_sssr = read_SSSR(reg);
		if ((trailing_sssr & 0xf008) != 0xf000) {
			drv_data->rx = drv_data->rx_end -
					(((trailing_sssr >> 12) & 0x0f) + 1);
			drv_data->read(drv_data);
		}
		msg->actual_length += drv_data->len;

		/* Release chip select if requested, transfer delays are
		 * handled in pump_transfers */
		if (drv_data->cs_change)
			drv_data->cs_control(PXA2XX_CS_DEASSERT);

		/* Move to next transfer */
		msg->state = next_transfer(drv_data);

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

static irqreturn_t dma_transfer(struct driver_data *drv_data)
{
	u32 irq_status;
	u32 trailing_sssr = 0;
	struct spi_message *msg = drv_data->cur_msg;
	void *reg = drv_data->ioaddr;

	irq_status = read_SSSR(reg) & drv_data->mask_sr;
	if (irq_status & SSSR_ROR) {
		/* Clear and disable interrupts on SSP and DMA channels*/
		if (drv_data->ssp_type != PXA25x_SSP)
			write_SSTO(0, reg);
		write_SSSR(drv_data->clear_sr, reg);
		write_SSCR1(read_SSCR1(reg) & ~drv_data->dma_cr1, reg);
		DCSR(drv_data->tx_channel) = RESET_DMA_CHANNEL;
		DCSR(drv_data->rx_channel) = RESET_DMA_CHANNEL;
		unmap_dma_buffers(drv_data);

		if (flush(drv_data) == 0)
			dev_err(&drv_data->pdev->dev,
					"dma_transfer: flush fail\n");

		dev_warn(&drv_data->pdev->dev, "dma_transfer: fifo overun\n");

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

		return IRQ_HANDLED;
	}

	/* Check for false positive timeout */
	if ((irq_status & SSSR_TINT) && DCSR(drv_data->tx_channel) & DCSR_RUN) {
		write_SSSR(SSSR_TINT, reg);
		return IRQ_HANDLED;
	}

	if (irq_status & SSSR_TINT || drv_data->rx == drv_data->rx_end) {

		/* Clear and disable interrupts on SSP and DMA channels*/
		if (drv_data->ssp_type != PXA25x_SSP)
			write_SSTO(0, reg);
		write_SSSR(drv_data->clear_sr, reg);
		write_SSCR1(read_SSCR1(reg) & ~drv_data->dma_cr1, reg);
		DCSR(drv_data->tx_channel) = RESET_DMA_CHANNEL;
		DCSR(drv_data->rx_channel) = RESET_DMA_CHANNEL;

		if (wait_dma_channel_stop(drv_data->rx_channel) == 0)
			dev_err(&drv_data->pdev->dev,
				"dma_transfer: dma rx channel stop failed\n");

		if (wait_ssp_rx_stall(drv_data->ioaddr) == 0)
			dev_err(&drv_data->pdev->dev,
				"dma_transfer: ssp rx stall failed\n");

		unmap_dma_buffers(drv_data);

		/* Calculate number of trailing bytes, read them */
		trailing_sssr = read_SSSR(reg);
		if ((trailing_sssr & 0xf008) != 0xf000) {
			drv_data->rx = drv_data->rx_end -
					(((trailing_sssr >> 12) & 0x0f) + 1);
			drv_data->read(drv_data);
		}
		msg->actual_length += drv_data->len;

		/* Release chip select if requested, transfer delays are
		 * handled in pump_transfers */
		if (drv_data->cs_change)
			drv_data->cs_control(PXA2XX_CS_DEASSERT);

		/* Move to next transfer */
		msg->state = next_transfer(drv_data);

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

		return IRQ_HANDLED;
	}

	/* Opps problem detected */
	return IRQ_NONE;
}

static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
{
	u32 irq_status;
	struct spi_message *msg = drv_data->cur_msg;
	void *reg = drv_data->ioaddr;
	irqreturn_t handled = IRQ_NONE;
	unsigned long limit = loops_per_jiffy << 1;

	while ((irq_status = (read_SSSR(reg) & drv_data->mask_sr))) {

		if (irq_status & SSSR_ROR) {

			/* Clear and disable interrupts */
			if (drv_data->ssp_type != PXA25x_SSP)
				write_SSTO(0, reg);
			write_SSSR(drv_data->clear_sr, reg);
			write_SSCR1(read_SSCR1(reg) & ~drv_data->int_cr1, reg);

			if (flush(drv_data) == 0)
				dev_err(&drv_data->pdev->dev,
					"interrupt_transfer: flush fail\n");

			dev_warn(&drv_data->pdev->dev,
					"interrupt_transfer: fifo overun\n");

			msg->state = ERROR_STATE;
			tasklet_schedule(&drv_data->pump_transfers);

			return IRQ_HANDLED;
		}

		/* Look for false positive timeout */
		if ((irq_status & SSSR_TINT)
				&& (drv_data->rx < drv_data->rx_end))
			write_SSSR(SSSR_TINT, reg);

		/* Pump data */
		drv_data->read(drv_data);
		drv_data->write(drv_data);

		if (drv_data->tx == drv_data->tx_end) {
			/* Disable tx interrupt */
			write_SSCR1(read_SSCR1(reg) & ~SSCR1_TIE, reg);

			/* PXA25x_SSP has no timeout, read trailing bytes */
			if (drv_data->ssp_type == PXA25x_SSP) {
				while ((read_SSSR(reg) & SSSR_BSY) && limit--)
					drv_data->read(drv_data);

				if (limit == 0)
					dev_err(&drv_data->pdev->dev,
						"interrupt_transfer: "
						"trailing byte read failed\n");
			}
		}

		if ((irq_status & SSSR_TINT)
				|| (drv_data->rx == drv_data->rx_end)) {

			/* Clear timeout */
			if (drv_data->ssp_type != PXA25x_SSP)
				write_SSTO(0, reg);
			write_SSSR(drv_data->clear_sr, reg);
			write_SSCR1(read_SSCR1(reg) & ~drv_data->int_cr1, reg);

			/* Update total byte transfered */
			msg->actual_length += drv_data->len;

			/* Release chip select if requested, transfer delays are
			 * handled in pump_transfers */
			if (drv_data->cs_change)
				drv_data->cs_control(PXA2XX_CS_DEASSERT);

			/* Move to next transfer */
			msg->state = next_transfer(drv_data);

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

			return IRQ_HANDLED;
		}

		/* We did something */
		handled = IRQ_HANDLED;
	}

	return handled;
}

static irqreturn_t ssp_int(int irq, void *dev_id, struct pt_regs *regs)
{
	struct driver_data *drv_data = (struct driver_data *)dev_id;

	if (!drv_data->cur_msg) {
		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);
}

static void pump_transfers(unsigned long data)
{
	struct driver_data *drv_data = (struct driver_data *)data;
	struct spi_message *message = NULL;
	struct spi_transfer *transfer = NULL;
	struct spi_transfer *previous = NULL;
	struct chip_data *chip = NULL;
	void *reg = drv_data->ioaddr;

	/* Get current state information */
	message = drv_data->cur_msg;
	transfer = drv_data->cur_transfer;
	chip = drv_data->cur_chip;

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

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

	/* Delay if requested at end of transfer*/
	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);
	}

	/* Setup the transfer state based on the type of transfer */
	if (flush(drv_data) == 0) {
		dev_err(&drv_data->pdev->dev, "pump_transfers: flush failed\n");
		message->status = -EIO;
		giveback(message, drv_data);
		return;
	}
	drv_data->cs_control = chip->cs_control;
	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->rx_dma = transfer->rx_dma;
	drv_data->tx_dma = transfer->tx_dma;
	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;
	drv_data->cs_change = transfer->cs_change;
	message->state = RUNNING_STATE;

	/* Try to map dma buffer and do a dma transfer if successful */
	if ((drv_data->dma_mapped = map_dma_buffers(drv_data))) {

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

		/* Setup rx DMA Channel */
		DCSR(drv_data->rx_channel) = RESET_DMA_CHANNEL;
		DSADR(drv_data->rx_channel) = drv_data->ssdr_physical;
		DTADR(drv_data->rx_channel) = drv_data->rx_dma;
		if (drv_data->rx == drv_data->null_dma_buf)
			/* No target address increment */
			DCMD(drv_data->rx_channel) = DCMD_FLOWSRC
							| chip->dma_width
							| chip->dma_burst_size
							| drv_data->len;
		else
			DCMD(drv_data->rx_channel) = DCMD_INCTRGADDR
							| DCMD_FLOWSRC
							| chip->dma_width
							| chip->dma_burst_size
							| drv_data->len;

		/* Setup tx DMA Channel */
		DCSR(drv_data->tx_channel) = RESET_DMA_CHANNEL;
		DSADR(drv_data->tx_channel) = drv_data->tx_dma;
		DTADR(drv_data->tx_channel) = drv_data->ssdr_physical;
		if (drv_data->tx == drv_data->null_dma_buf)
			/* No source address increment */
			DCMD(drv_data->tx_channel) = DCMD_FLOWTRG
							| chip->dma_width
							| chip->dma_burst_size
							| drv_data->len;
		else
			DCMD(drv_data->tx_channel) = DCMD_INCSRCADDR
							| DCMD_FLOWTRG
							| chip->dma_width
							| chip->dma_burst_size
							| drv_data->len;

		/* Enable dma end irqs on SSP to detect end of transfer */
		if (drv_data->ssp_type == PXA25x_SSP)
			DCMD(drv_data->tx_channel) |= DCMD_ENDIRQEN;

		/* Fix me, need to handle cs polarity */
		drv_data->cs_control(PXA2XX_CS_ASSERT);

		/* Go baby, go */
		write_SSSR(drv_data->clear_sr, reg);
		DCSR(drv_data->rx_channel) |= DCSR_RUN;
		DCSR(drv_data->tx_channel) |= DCSR_RUN;
		if (drv_data->ssp_type != PXA25x_SSP)
			write_SSTO(chip->timeout, reg);
		write_SSCR1(chip->cr1
				| chip->dma_threshold
				| drv_data->dma_cr1,
				reg);
	} else {
		/* Ensure we have the correct interrupt handler	*/
		drv_data->transfer_handler = interrupt_transfer;

		/* Fix me, need to handle cs polarity */
		drv_data->cs_control(PXA2XX_CS_ASSERT);

		/* Go baby, go */
		write_SSSR(drv_data->clear_sr, reg);
		if (drv_data->ssp_type != PXA25x_SSP)
			write_SSTO(chip->timeout, reg);
		write_SSCR1(chip->cr1
				| chip->threshold
				| drv_data->int_cr1,
				reg);
	}
}

static void pump_messages(void *data)
{
	struct driver_data *drv_data = data;
	unsigned long flags;

	/* Lock queue and check for queue work */
	spin_lock_irqsave(&drv_data->lock, flags);
	if (list_empty(&drv_data->queue) || drv_data->run == QUEUE_STOPPED) {
		drv_data->busy = 0;
		spin_unlock_irqrestore(&drv_data->lock, flags);
		return;
	}

	/* Make sure we are not already running a message */
	if (drv_data->cur_msg) {
		spin_unlock_irqrestore(&drv_data->lock, flags);
		return;
	}

	/* Extract head of queue */
	drv_data->cur_msg = list_entry(drv_data->queue.next,
					struct spi_message, queue);
	list_del_init(&drv_data->cur_msg->queue);
	drv_data->busy = 1;
	spin_unlock_irqrestore(&drv_data->lock, flags);

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

	/* Setup the SSP using the per chip configuration */
	drv_data->cur_chip = spi_get_ctldata(drv_data->cur_msg->spi);
	restore_state(drv_data);

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

static int transfer(struct spi_device *spi, struct spi_message *msg)
{
	struct driver_data *drv_data = spi_master_get_devdata(spi->master);
	unsigned long flags;

	spin_lock_irqsave(&drv_data->lock, flags);

	if (drv_data->run == QUEUE_STOPPED) {
		spin_unlock_irqrestore(&drv_data->lock, flags);
		return -ESHUTDOWN;
	}

	msg->actual_length = 0;
	msg->status = -EINPROGRESS;
	msg->state = START_STATE;

	list_add_tail(&msg->queue, &drv_data->queue);

	if (drv_data->run == QUEUE_RUNNING && !drv_data->busy)
		queue_work(drv_data->workqueue, &drv_data->pump_messages);

	spin_unlock_irqrestore(&drv_data->lock, flags);

	return 0;
}

static int setup(struct spi_device *spi)
{
	struct pxa2xx_spi_chip *chip_info = NULL;
	struct chip_data *chip;
	struct driver_data *drv_data = spi_master_get_devdata(spi->master);
	unsigned int clk_div;

	if (!spi->bits_per_word)
		spi->bits_per_word = 8;

	if (drv_data->ssp_type != PXA25x_SSP
			&& (spi->bits_per_word < 4 || spi->bits_per_word > 32))
		return -EINVAL;
	else if (spi->bits_per_word < 4 || spi->bits_per_word > 16)
		return -EINVAL;

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

		chip->cs_control = null_cs_control;
		chip->enable_dma = 0;
		chip->timeout = 5;
		chip->threshold = SSCR1_RxTresh(1) | SSCR1_TxTresh(1);
		chip->dma_burst_size = drv_data->master_info->enable_dma ?
					DCMD_BURST8 : 0;

		chip_info = spi->controller_data;
	}

	/* chip_info isn't always needed */
	if (chip_info) {
		if (chip_info->cs_control)
			chip->cs_control = chip_info->cs_control;

		chip->timeout = (chip_info->timeout_microsecs * 10000) / 2712;

		chip->threshold = SSCR1_RxTresh(chip_info->rx_threshold)
					| SSCR1_TxTresh(chip_info->tx_threshold);

		chip->enable_dma = chip_info->dma_burst_size != 0
					&& drv_data->master_info->enable_dma;
		chip->dma_threshold = 0;

		if (chip->enable_dma) {
			if (chip_info->dma_burst_size <= 8) {
				chip->dma_threshold = SSCR1_RxTresh(8)
							| SSCR1_TxTresh(8);
				chip->dma_burst_size = DCMD_BURST8;
			} else if (chip_info->dma_burst_size <= 16) {
				chip->dma_threshold = SSCR1_RxTresh(16)
							| SSCR1_TxTresh(16);
				chip->dma_burst_size = DCMD_BURST16;
			} else {
				chip->dma_threshold = SSCR1_RxTresh(32)
							| SSCR1_TxTresh(32);
				chip->dma_burst_size = DCMD_BURST32;
			}
		}


		if (chip_info->enable_loopback)
			chip->cr1 = SSCR1_LBM;
	}

	if (drv_data->ioaddr == SSP1_VIRT)
		clk_div = SSP1_SerClkDiv(spi->max_speed_hz);
	else if (drv_data->ioaddr == SSP2_VIRT)
		clk_div = SSP2_SerClkDiv(spi->max_speed_hz);
	else if (drv_data->ioaddr == SSP3_VIRT)
		clk_div = SSP3_SerClkDiv(spi->max_speed_hz);
	else
		return -ENODEV;

	chip->cr0 = clk_div
			| SSCR0_Motorola
			| SSCR0_DataSize(spi->bits_per_word & 0x0f)
			| SSCR0_SSE
			| (spi->bits_per_word > 16 ? SSCR0_EDSS : 0);
	chip->cr1 |= (((spi->mode & SPI_CPHA) != 0) << 4)
			| (((spi->mode & SPI_CPOL) != 0) << 3);

	/* NOTE:  PXA25x_SSP _could_ use external clocking ... */
	if (drv_data->ssp_type != PXA25x_SSP)
		dev_dbg(&spi->dev, "%d bits/word, %d Hz, mode %d\n",
				spi->bits_per_word,
				(CLOCK_SPEED_HZ)
					/ (1 + ((chip->cr0 & SSCR0_SCR) >> 8)),
				spi->mode & 0x3);
	else
		dev_dbg(&spi->dev, "%d bits/word, %d Hz, mode %d\n",
				spi->bits_per_word,
				(CLOCK_SPEED_HZ/2)
					/ (1 + ((chip->cr0 & SSCR0_SCR) >> 8)),
				spi->mode & 0x3);

	if (spi->bits_per_word <= 8) {
		chip->n_bytes = 1;
		chip->dma_width = DCMD_WIDTH1;
		chip->read = u8_reader;
		chip->write = u8_writer;
	} else if (spi->bits_per_word <= 16) {
		chip->n_bytes = 2;
		chip->dma_width = DCMD_WIDTH2;
		chip->read = u16_reader;
		chip->write = u16_writer;
	} else if (spi->bits_per_word <= 32) {
		chip->cr0 |= SSCR0_EDSS;
		chip->n_bytes = 4;
		chip->dma_width = DCMD_WIDTH4;
		chip->read = u32_reader;
		chip->write = u32_writer;
	} else {
		dev_err(&spi->dev, "invalid wordsize\n");
		kfree(chip);
		return -ENODEV;
	}

	spi_set_ctldata(spi, chip);

	return 0;
}

static void cleanup(const struct spi_device *spi)
{
	struct chip_data *chip = spi_get_ctldata((struct spi_device *)spi);

	kfree(chip);
}

static int init_queue(struct driver_data *drv_data)
{
	INIT_LIST_HEAD(&drv_data->queue);
	spin_lock_init(&drv_data->lock);

	drv_data->run = QUEUE_STOPPED;
	drv_data->busy = 0;

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

	INIT_WORK(&drv_data->pump_messages, pump_messages, drv_data);
	drv_data->workqueue = create_singlethread_workqueue(
					drv_data->master->cdev.dev->bus_id);
	if (drv_data->workqueue == NULL)
		return -EBUSY;

	return 0;
}

static int start_queue(struct driver_data *drv_data)
{
	unsigned long flags;

	spin_lock_irqsave(&drv_data->lock, flags);

	if (drv_data->run == QUEUE_RUNNING || drv_data->busy) {
		spin_unlock_irqrestore(&drv_data->lock, flags);
		return -EBUSY;
	}

	drv_data->run = QUEUE_RUNNING;
	drv_data->cur_msg = NULL;
	drv_data->cur_transfer = NULL;
	drv_data->cur_chip = NULL;
	spin_unlock_irqrestore(&drv_data->lock, flags);

	queue_work(drv_data->workqueue, &drv_data->pump_messages);

	return 0;
}

static int stop_queue(struct driver_data *drv_data)
{
	unsigned long flags;
	unsigned limit = 500;
	int status = 0;

	spin_lock_irqsave(&drv_data->lock, flags);

	/* This is a bit lame, but is optimized for the common execution path.
	 * A wait_queue on the drv_data->busy could be used, but then the common
	 * execution path (pump_messages) would be required to call wake_up or
	 * friends on every SPI message. Do this instead */
	drv_data->run = QUEUE_STOPPED;
	while (!list_empty(&drv_data->queue) && drv_data->busy && limit--) {
		spin_unlock_irqrestore(&drv_data->lock, flags);
		msleep(10);
		spin_lock_irqsave(&drv_data->lock, flags);
	}

	if (!list_empty(&drv_data->queue) || drv_data->busy)
		status = -EBUSY;

	spin_unlock_irqrestore(&drv_data->lock, flags);

	return status;
}

static int destroy_queue(struct driver_data *drv_data)
{
	int status;

	status = stop_queue(drv_data);
	if (status != 0)
		return status;

	destroy_workqueue(drv_data->workqueue);

	return 0;
}

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 = 0;
	struct resource *memory_resource;
	int irq;
	int status = 0;

	platform_info = dev->platform_data;

	if (platform_info->ssp_type == SSP_UNDEFINED) {
		dev_err(&pdev->dev, "undefined SSP\n");
		return -ENODEV;
	}

	/* Allocate master with space for drv_data and null dma buffer */
	master = spi_alloc_master(dev, sizeof(struct driver_data) + 16);
	if (!master) {
		dev_err(&pdev->dev, "can not alloc spi_master\n");
		return -ENOMEM;
	}
	drv_data = spi_master_get_devdata(master);
	drv_data->master = master;
	drv_data->master_info = platform_info;
	drv_data->pdev = pdev;

	master->bus_num = pdev->id;
	master->num_chipselect = platform_info->num_chipselect;
	master->cleanup = cleanup;
	master->setup = setup;
	master->transfer = transfer;

	drv_data->ssp_type = platform_info->ssp_type;
	drv_data->null_dma_buf = (u32 *)ALIGN((u32)(drv_data +
						sizeof(struct driver_data)), 8);

	/* Setup register addresses */
	memory_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!memory_resource) {
		dev_err(&pdev->dev, "memory resources not defined\n");
		status = -ENODEV;
		goto out_error_master_alloc;
	}

	drv_data->ioaddr = (void *)io_p2v(memory_resource->start);
	drv_data->ssdr_physical = memory_resource->start + 0x00000010;
	if (platform_info->ssp_type == PXA25x_SSP) {
		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 {
		drv_data->int_cr1 = SSCR1_TIE | SSCR1_RIE | SSCR1_TINTE;
		drv_data->dma_cr1 = SSCR1_TSRE | SSCR1_RSRE | SSCR1_TINTE;
		drv_data->clear_sr = SSSR_ROR | SSSR_TINT;
		drv_data->mask_sr = SSSR_TINT | SSSR_RFS | SSSR_TFS | SSSR_ROR;
	}

	/* Attach to IRQ */
	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		dev_err(&pdev->dev, "irq resource not defined\n");
		status = -ENODEV;
		goto out_error_master_alloc;
	}

	status = request_irq(irq, ssp_int, SA_INTERRUPT, dev->bus_id, drv_data);
	if (status < 0) {
		dev_err(&pdev->dev, "can not get IRQ\n");
		goto out_error_master_alloc;
	}

	/* Setup DMA if requested */
	drv_data->tx_channel = -1;
	drv_data->rx_channel = -1;
	if (platform_info->enable_dma) {

		/* Get two DMA channels	(rx and tx) */
		drv_data->rx_channel = pxa_request_dma("pxa2xx_spi_ssp_rx",
							DMA_PRIO_HIGH,
							dma_handler,
							drv_data);
		if (drv_data->rx_channel < 0) {
			dev_err(dev, "problem (%d) requesting rx channel\n",
				drv_data->rx_channel);
			status = -ENODEV;
			goto out_error_irq_alloc;
		}
		drv_data->tx_channel = pxa_request_dma("pxa2xx_spi_ssp_tx",
							DMA_PRIO_MEDIUM,
							dma_handler,
							drv_data);
		if (drv_data->tx_channel < 0) {
			dev_err(dev, "problem (%d) requesting tx channel\n",
				drv_data->tx_channel);
			status = -ENODEV;
			goto out_error_dma_alloc;
		}

		if (drv_data->ioaddr == SSP1_VIRT) {
				DRCMRRXSSDR = DRCMR_MAPVLD
						| drv_data->rx_channel;
				DRCMRTXSSDR = DRCMR_MAPVLD
						| drv_data->tx_channel;
		} else if (drv_data->ioaddr == SSP2_VIRT) {
				DRCMRRXSS2DR = DRCMR_MAPVLD
						| drv_data->rx_channel;
				DRCMRTXSS2DR = DRCMR_MAPVLD
						| drv_data->tx_channel;
		} else if (drv_data->ioaddr == SSP3_VIRT) {
				DRCMRRXSS3DR = DRCMR_MAPVLD
						| drv_data->rx_channel;
				DRCMRTXSS3DR = DRCMR_MAPVLD
						| drv_data->tx_channel;
		} else {
			dev_err(dev, "bad SSP type\n");
			goto out_error_dma_alloc;
		}
	}

	/* Enable SOC clock */
	pxa_set_cken(platform_info->clock_enable, 1);

	/* Load default SSP configuration */
	write_SSCR0(0, drv_data->ioaddr);
	write_SSCR1(SSCR1_RxTresh(4) | SSCR1_TxTresh(12), drv_data->ioaddr);
	write_SSCR0(SSCR0_SerClkDiv(2)
			| SSCR0_Motorola
			| SSCR0_DataSize(8),
			drv_data->ioaddr);
	if (drv_data->ssp_type != PXA25x_SSP)
		write_SSTO(0, drv_data->ioaddr);
	write_SSPSP(0, drv_data->ioaddr);

	/* Initial and start queue */
	status = init_queue(drv_data);
	if (status != 0) {
		dev_err(&pdev->dev, "problem initializing queue\n");
		goto out_error_clock_enabled;
	}
	status = start_queue(drv_data);
	if (status != 0) {
		dev_err(&pdev->dev, "problem starting queue\n");
		goto out_error_clock_enabled;
	}

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

	return status;

out_error_queue_alloc:
	destroy_queue(drv_data);

out_error_clock_enabled:
	pxa_set_cken(platform_info->clock_enable, 0);

out_error_dma_alloc:
	if (drv_data->tx_channel != -1)
		pxa_free_dma(drv_data->tx_channel);
	if (drv_data->rx_channel != -1)
		pxa_free_dma(drv_data->rx_channel);

out_error_irq_alloc:
	free_irq(irq, drv_data);

out_error_master_alloc:
	spi_master_put(master);
	return status;
}

static int pxa2xx_spi_remove(struct platform_device *pdev)
{
	struct driver_data *drv_data = platform_get_drvdata(pdev);
	int irq;
	int status = 0;

	if (!drv_data)
		return 0;

	/* Remove the queue */
	status = destroy_queue(drv_data);
	if (status != 0)
		return status;

	/* Disable the SSP at the peripheral and SOC level */
	write_SSCR0(0, drv_data->ioaddr);
	pxa_set_cken(drv_data->master_info->clock_enable, 0);

	/* Release DMA */
	if (drv_data->master_info->enable_dma) {
		if (drv_data->ioaddr == SSP1_VIRT) {
			DRCMRRXSSDR = 0;
			DRCMRTXSSDR = 0;
		} else if (drv_data->ioaddr == SSP2_VIRT) {
			DRCMRRXSS2DR = 0;
			DRCMRTXSS2DR = 0;
		} else if (drv_data->ioaddr == SSP3_VIRT) {
			DRCMRRXSS3DR = 0;
			DRCMRTXSS3DR = 0;
		}
		pxa_free_dma(drv_data->tx_channel);
		pxa_free_dma(drv_data->rx_channel);
	}

	/* Release IRQ */
	irq = platform_get_irq(pdev, 0);
	if (irq >= 0)
		free_irq(irq, drv_data);

	/* Disconnect from the SPI framework */
	spi_unregister_master(drv_data->master);

	/* Prevent double remove */
	platform_set_drvdata(pdev, NULL);

	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
static int suspend_devices(struct device *dev, void *pm_message)
{
	pm_message_t *state = pm_message;

	if (dev->power.power_state.event != state->event) {
		dev_warn(dev, "pm state does not match request\n");
		return -1;
	}

	return 0;
}

static int pxa2xx_spi_suspend(struct platform_device *pdev, pm_message_t state)
{
	struct driver_data *drv_data = platform_get_drvdata(pdev);
	int status = 0;

	/* Check all childern for current power state */
	if (device_for_each_child(&pdev->dev, &state, suspend_devices) != 0) {
		dev_warn(&pdev->dev, "suspend aborted\n");
		return -1;
	}

	status = stop_queue(drv_data);
	if (status != 0)
		return status;
	write_SSCR0(0, drv_data->ioaddr);
	pxa_set_cken(drv_data->master_info->clock_enable, 0);

	return 0;
}

static int pxa2xx_spi_resume(struct platform_device *pdev)
{
	struct driver_data *drv_data = platform_get_drvdata(pdev);
	int status = 0;

	/* Enable the SSP clock */
	pxa_set_cken(drv_data->master_info->clock_enable, 1);

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

	return 0;
}
#else
#define pxa2xx_spi_suspend NULL
#define pxa2xx_spi_resume NULL
#endif /* CONFIG_PM */

static struct platform_driver driver = {
	.driver = {
		.name = "pxa2xx-spi",
		.bus = &platform_bus_type,
		.owner = THIS_MODULE,
	},
	.probe = pxa2xx_spi_probe,
	.remove = __devexit_p(pxa2xx_spi_remove),
	.shutdown = pxa2xx_spi_shutdown,
	.suspend = pxa2xx_spi_suspend,
	.resume = pxa2xx_spi_resume,
};

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

	return 0;
}
module_init(pxa2xx_spi_init);

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