[PATCH] Blackfin: blackfin on-chip SPI controller driver

["Wu, Bryan" <bryan.wu@analog.com>]

Hi folks,

Here is the latest blackfin on-chip SPI controller driver for
2.6.21-rc2-mm1

[PATCH] Blackfin: blackfin on-chip SPI controller driver

This patch implements the driver necessary use the Analog Devices
Blackfin processor's SPI Port.

Signed-off-by: Bryan Wu <bryan.wu@analog.com>
---

 drivers/spi/Kconfig       |    6
 drivers/spi/Makefile      |    1
 drivers/spi/spi_bfin5xx.c | 1261 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1267 insertions(+), 1 deletion(-)

Index: linux-2.6/drivers/spi/Kconfig
===================================================================
--- linux-2.6.orig/drivers/spi/Kconfig	2007-03-01 11:33:07.000000000 +0800
+++ linux-2.6/drivers/spi/Kconfig	2007-03-01 11:40:22.000000000 +0800
@@ -156,7 +156,11 @@
 #
 # Add new SPI protocol masters in alphabetical order above this line
 #
-
+config SPI_BFIN
+	tristate "SPI controller driver for ADI Blackfin5xx"
+	depends on SPI_MASTER && BFIN
+	help
+	  This is the SPI controller master driver for Blackfin 5xx processor.
 
 # (slave support would go here)
 
Index: linux-2.6/drivers/spi/Makefile
===================================================================
--- linux-2.6.orig/drivers/spi/Makefile	2007-03-01 11:33:07.000000000 +0800
+++ linux-2.6/drivers/spi/Makefile	2007-03-01 11:40:22.000000000 +0800
@@ -20,6 +20,7 @@
 obj-$(CONFIG_SPI_MPC83xx)		+= spi_mpc83xx.o
 obj-$(CONFIG_SPI_S3C24XX_GPIO)		+= spi_s3c24xx_gpio.o
 obj-$(CONFIG_SPI_S3C24XX)		+= spi_s3c24xx.o
+obj-$(CONFIG_SPI_BFIN)			+= spi_bfin5xx.o
 # 	... add above this line ...
 
 # SPI protocol drivers (device/link on bus)
Index: linux-2.6/drivers/spi/spi_bfin5xx.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6/drivers/spi/spi_bfin5xx.c	2007-03-01 11:40:22.000000000 +0800
@@ -0,0 +1,1261 @@
+/*
+ * File:         drivers/spi/bfin5xx_spi.c
+ * Based on:     N/A
+ * Author:       Luke Yang (Analog Devices Inc.)
+ *
+ * Created:      March. 10th 2006
+ * Description:  SPI controller driver for Blackfin 5xx
+ * Bugs:         Enter bugs at http://blackfin.uclinux.org/
+ *
+ * Rev:          $Id: spi_bfin5xx.c 2508 2006-12-06 07:35:43Z sonicz $
+ *
+ * Modified:
+ *	March 10, 2006  bfin5xx_spi.c Created. (Luke Yang)
+ *      August 7, 2006  added full duplex mode (Axel Weiss & Luke Yang)
+ *
+ * Copyright 2004-2006 Analog Devices Inc.
+ *
+ * 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, 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 ;  see the file COPYING.
+ * If not, write to the Free Software Foundation,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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/delay.h>
+#include <asm/dma.h>
+
+#include <asm/bfin5xx_spi.h>
+
+MODULE_AUTHOR("Luke Yang");
+MODULE_DESCRIPTION("Blackfin 5xx SPI Contoller");
+MODULE_LICENSE("GPL");
+
+#ifdef DEBUG
+#define ASSERT(expr) \
+	if (!(expr)) { \
+		printk(KERN_DEBUG "assertion failed! %s[%d]: %s\n", \
+		       __FUNCTION__, __LINE__, #expr); \
+		panic(KERN_DEBUG "%s", __FUNCTION__); \
+	}
+#else
+#define ASSERT(expr)
+#endif
+
+#define IS_DMA_ALIGNED(x) (((u32)(x)&0x07)==0)
+
+#define DEFINE_SPI_REG(reg, off) \
+static inline u16 read_##reg(void) \
+            { return *(volatile unsigned short*)(SPI0_REGBASE + off); } \
+static inline void write_##reg(u16 v) \
+            {*(volatile unsigned short*)(SPI0_REGBASE + off) = v;\
+             SSYNC();}
+
+DEFINE_SPI_REG(CTRL, 0x00)
+DEFINE_SPI_REG(FLAG, 0x04)
+DEFINE_SPI_REG(STAT, 0x08)
+DEFINE_SPI_REG(TDBR, 0x0C)
+DEFINE_SPI_REG(RDBR, 0x10)
+DEFINE_SPI_REG(BAUD, 0x14)
+DEFINE_SPI_REG(SHAW, 0x18)
+
+#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
+
+int dma_requested;
+char chip_select_flag;
+
+struct driver_data {
+	/* Driver model hookup */
+	struct platform_device *pdev;
+
+	/* SPI framework hookup */
+	struct spi_master *master;
+
+	/* BFIN hookup */
+	struct bfin5xx_spi_master *master_info;
+
+	/* 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_in_bytes;
+	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;
+	u8 n_bytes;
+	void (*write) (struct driver_data *);
+	void (*read) (struct driver_data *);
+	void (*duplex) (struct driver_data *);
+};
+
+struct chip_data {
+	u16 ctl_reg;
+	u16 baud;
+	u16 flag;
+
+	u8 chip_select_num;
+	u8 n_bytes;
+	u32 width;		/* 0 or 1 */
+	u8 enable_dma;
+	u8 bits_per_word;	/* 8 or 16 */
+	u8 cs_change_per_word;
+	u8 cs_chg_udelay;
+	void (*write) (struct driver_data *);
+	void (*read) (struct driver_data *);
+	void (*duplex) (struct driver_data *);
+};
+
+void bfin_spi_enable(struct driver_data *drv_data)
+{
+	u16 cr;
+
+	cr = read_CTRL();
+	write_CTRL(cr | BIT_CTL_ENABLE);
+	SSYNC();
+}
+
+void bfin_spi_disable(struct driver_data *drv_data)
+{
+	u16 cr;
+
+	cr = read_CTRL();
+	write_CTRL(cr & (~BIT_CTL_ENABLE));
+	SSYNC();
+}
+
+/* Caculate the SPI_BAUD register value based on input HZ */
+static u16 hz_to_spi_baud(u32 speed_hz)
+{
+	u_long sclk = get_sclk();
+	u16 spi_baud = (sclk / (2*speed_hz));
+
+	if ((sclk % (2*speed_hz)) > 0)
+		spi_baud++;
+
+	pr_debug("sclk = %ld, speed_hz = %d, spi_baud = %d\n", sclk, speed_hz, spi_baud);
+	
+	return spi_baud;
+}
+
+static int flush(struct driver_data *drv_data)
+{
+	unsigned long limit = loops_per_jiffy << 1;
+
+	/* wait for stop and clear stat */
+	do {} while (!(read_STAT() & BIT_STAT_SPIF) && limit--);
+	write_STAT(BIT_STAT_CLR);
+
+	return limit;
+}
+
+/* stop controller and re-config current chip*/
+static void restore_state(struct driver_data *drv_data)
+{
+	struct chip_data *chip = drv_data->cur_chip;
+
+	/* Clear status and disable clock */
+	write_STAT(BIT_STAT_CLR);
+	bfin_spi_disable(drv_data);
+	pr_debug("restoring spi ctl state\n");
+
+#if defined(CONFIG_BF534)||defined(CONFIG_BF536)||defined(CONFIG_BF537)
+	if (chip->chip_select_num == 1) {
+		pr_debug("set for chip select 1\n");
+		bfin_write_PORTF_FER(bfin_read_PORTF_FER() | 0x3c00);
+		SSYNC();
+
+	} else if (chip->chip_select_num == 2 || chip->chip_select_num == 3) {
+		pr_debug("set for chip select 2\n");
+		bfin_write_PORT_MUX(bfin_read_PORT_MUX() | PJSE_SPI);
+		SSYNC();
+		bfin_write_PORTF_FER(bfin_read_PORTF_FER() | 0x3800);
+		SSYNC();
+
+	} else if (chip->chip_select_num == 4) {
+		bfin_write_PORT_MUX(bfin_read_PORT_MUX() | PFS4E_SPI);
+		SSYNC();
+		bfin_write_PORTF_FER(bfin_read_PORTF_FER() | 0x3840);
+		SSYNC();
+
+	} else if (chip->chip_select_num == 5) {
+		bfin_write_PORT_MUX(bfin_read_PORT_MUX() | PFS5E_SPI);
+		SSYNC();
+		bfin_write_PORTF_FER(bfin_read_PORTF_FER() | 0x3820);
+		SSYNC();
+
+	} else if (chip->chip_select_num == 6) {
+		bfin_write_PORT_MUX(bfin_read_PORT_MUX() | PFS6E_SPI);
+		SSYNC();
+		bfin_write_PORTF_FER(bfin_read_PORTF_FER() | 0x3810);
+		SSYNC();
+
+	} else if (chip->chip_select_num == 7) {
+		bfin_write_PORT_MUX(bfin_read_PORT_MUX() | PJCE_SPI);
+		SSYNC();
+		bfin_write_PORTF_FER(bfin_read_PORTF_FER() | 0x3800);
+		SSYNC();
+	}
+#endif
+
+	/* Load the registers */
+	write_CTRL(chip->ctl_reg);
+	write_BAUD(chip->baud);
+	write_FLAG(chip->flag);
+}
+
+/* used to kick off transfer in rx mode */
+static unsigned short dummy_read(void)
+{
+	unsigned short tmp;
+	tmp = read_RDBR();
+	return tmp;
+}
+
+static void null_writer(struct driver_data *drv_data)
+{
+	u8 n_bytes = drv_data->n_bytes;
+
+	while (drv_data->tx < drv_data->tx_end) {
+		write_TDBR(0);
+		do {} while ((read_STAT() & BIT_STAT_TXS));
+		drv_data->tx += n_bytes;
+	}
+}
+
+static void null_reader(struct driver_data *drv_data)
+{
+	u8 n_bytes = drv_data->n_bytes;
+	dummy_read();
+
+	while (drv_data->rx < drv_data->rx_end) {
+		do {} while (!(read_STAT() & BIT_STAT_RXS));
+		dummy_read();
+		drv_data->rx += n_bytes;
+	}
+}
+
+static void u8_writer(struct driver_data *drv_data)
+{
+	pr_debug("cr8-s is 0x%x\n", read_STAT());
+	while (drv_data->tx < drv_data->tx_end) {
+		write_TDBR(*(u8 *)(drv_data->tx));
+		do {} while (read_STAT() & BIT_STAT_TXS);
+		++drv_data->tx;
+	}
+
+	// poll for SPI completion before returning
+	do {} while (!(read_STAT() & BIT_STAT_SPIF));
+}
+
+static void u8_cs_chg_writer(struct driver_data *drv_data)
+{
+	struct chip_data *chip = drv_data->cur_chip;
+
+	while (drv_data->tx < drv_data->tx_end) {
+		write_FLAG(chip->flag);
+		SSYNC();
+
+		write_TDBR(*(u8 *)(drv_data->tx));
+		do {} while (read_STAT() & BIT_STAT_TXS);
+		do {} while (!(read_STAT() & BIT_STAT_SPIF));
+		write_FLAG(0xFF00|chip->flag);
+		SSYNC();
+		if (chip->cs_chg_udelay)
+			udelay(chip->cs_chg_udelay);
+		++drv_data->tx;
+	}
+	write_FLAG(0xFF00);
+	SSYNC();
+}
+
+static void u8_reader(struct driver_data *drv_data)
+{
+	pr_debug("cr-8 is 0x%x\n", read_STAT());
+
+	// clear TDBR buffer before read(else it will be shifted out)
+	write_TDBR(0xFFFF);
+
+	dummy_read();
+
+	while (drv_data->rx < drv_data->rx_end - 1) {
+		do {} while (!(read_STAT() & BIT_STAT_RXS));
+		*(u8 *)(drv_data->rx) = read_RDBR();
+		++drv_data->rx;
+	}
+	do {} while (!(read_STAT() & BIT_STAT_RXS));
+	*(u8 *)(drv_data->rx) = read_SHAW();
+	++drv_data->rx;
+}
+
+static void u8_cs_chg_reader(struct driver_data *drv_data)
+{
+	struct chip_data *chip = drv_data->cur_chip;
+
+	while (drv_data->rx < drv_data->rx_end) {
+		write_FLAG(chip->flag);
+		SSYNC();
+
+		read_RDBR(); /* kick off */
+		do {} while (!(read_STAT() & BIT_STAT_RXS));
+		do {} while (!(read_STAT() & BIT_STAT_SPIF));
+		*(u8 *)(drv_data->rx) = read_SHAW();
+		write_FLAG(0xFF00|chip->flag);
+		SSYNC();
+		if (chip->cs_chg_udelay)
+			udelay(chip->cs_chg_udelay);
+		++drv_data->rx;
+	}
+	write_FLAG(0xFF00);
+	SSYNC();
+}
+
+static void u8_duplex(struct driver_data *drv_data)
+{
+	/* in duplex mode, clk is triggered by writing of TDBR */
+	while (drv_data->rx < drv_data->rx_end) {
+		write_TDBR(*(u8 *)(drv_data->tx));
+		do {} while (!(read_STAT() & BIT_STAT_SPIF));
+		do {} while (!(read_STAT() & BIT_STAT_RXS));
+		*(u8 *)(drv_data->rx) = read_RDBR();
+		//if (*(u8 *)(drv_data->rx)) pr_debug(KERN_NOTICE "u8_duplex: %c\n", *(u8 *)(drv_data->rx));
+		++drv_data->rx;
+		++drv_data->tx;
+	}
+}
+
+static void u8_cs_chg_duplex(struct driver_data *drv_data)
+{
+	struct chip_data *chip = drv_data->cur_chip;
+
+	while (drv_data->rx < drv_data->rx_end) {
+		write_FLAG(chip->flag);
+		SSYNC();
+
+		write_TDBR(*(u8 *)(drv_data->tx));
+		do {} while (!(read_STAT() & BIT_STAT_SPIF));
+		do {} while (!(read_STAT() & BIT_STAT_RXS));
+		*(u8 *)(drv_data->rx) = read_RDBR();
+		write_FLAG(0xFF00|chip->flag);
+		SSYNC();
+		if (chip->cs_chg_udelay)
+			udelay(chip->cs_chg_udelay);
+		++drv_data->rx;
+		++drv_data->tx;
+	}
+	write_FLAG(0xFF00);
+	SSYNC();
+}
+
+static void u16_writer(struct driver_data *drv_data)
+{
+	pr_debug("cr16 is 0x%x\n", read_STAT());
+	while (drv_data->tx < drv_data->tx_end) {
+		write_TDBR(*(u16 *)(drv_data->tx));
+		do {} while ((read_STAT() & BIT_STAT_TXS));
+		drv_data->tx += 2;
+	}
+
+	// poll for SPI completion before returning
+	do {} while (!(read_STAT() & BIT_STAT_SPIF));
+}
+
+static void u16_cs_chg_writer(struct driver_data *drv_data)
+{
+	struct chip_data *chip = drv_data->cur_chip;
+
+	while (drv_data->tx < drv_data->tx_end) {
+		write_FLAG(chip->flag);
+		SSYNC();
+
+		write_TDBR(*(u16 *)(drv_data->tx));
+		do {} while ((read_STAT() & BIT_STAT_TXS));
+		do {} while (!(read_STAT() & BIT_STAT_SPIF));
+		write_FLAG(0xFF00|chip->flag);
+		SSYNC();
+		if (chip->cs_chg_udelay)
+			udelay(chip->cs_chg_udelay);
+		drv_data->tx += 2;
+	}
+	write_FLAG(0xFF00);
+	SSYNC();
+}
+
+static void u16_reader(struct driver_data *drv_data)
+{
+	pr_debug("cr-16 is 0x%x\n", read_STAT());
+	dummy_read();
+
+	while (drv_data->rx < (drv_data->rx_end - 2)) {
+		do {} while (!(read_STAT() & BIT_STAT_RXS));
+		*(u16 *)(drv_data->rx) = read_RDBR();
+		drv_data->rx += 2;
+	}
+	do {} while (!(read_STAT() & BIT_STAT_RXS));
+	*(u16 *)(drv_data->rx) = read_SHAW();
+	drv_data->rx += 2;
+}
+
+static void u16_cs_chg_reader(struct driver_data *drv_data)
+{
+	struct chip_data *chip = drv_data->cur_chip;
+
+	while (drv_data->rx < drv_data->rx_end) {
+		write_FLAG(chip->flag);
+		SSYNC();
+
+		read_RDBR();  /* kick off */
+		do {} while (!(read_STAT() & BIT_STAT_RXS));
+		do {} while (!(read_STAT() & BIT_STAT_SPIF));
+		*(u16 *)(drv_data->rx) = read_SHAW();
+		write_FLAG(0xFF00|chip->flag);
+		SSYNC();
+		if (chip->cs_chg_udelay)
+			udelay(chip->cs_chg_udelay);
+		drv_data->rx += 2;
+	}
+	write_FLAG(0xFF00);
+	SSYNC();
+}
+
+static void u16_duplex(struct driver_data *drv_data)
+{
+	/* in duplex mode, clk is triggered by writing of TDBR */
+	while (drv_data->tx < drv_data->tx_end) {
+		write_TDBR(*(u16 *)(drv_data->tx));
+		do {} while (!(read_STAT() & BIT_STAT_SPIF));
+		do {} while (!(read_STAT() & BIT_STAT_RXS));
+		*(u16 *)(drv_data->rx) = read_RDBR();
+		drv_data->rx += 2;
+		drv_data->tx += 2;
+	}
+}
+
+static void u16_cs_chg_duplex(struct driver_data *drv_data)
+{
+	struct chip_data *chip = drv_data->cur_chip;
+
+	while (drv_data->tx < drv_data->tx_end) {
+		write_FLAG(chip->flag);
+		SSYNC();
+
+		write_TDBR(*(u16 *)(drv_data->tx));
+		do {} while (!(read_STAT() & BIT_STAT_SPIF));
+		do {} while (!(read_STAT() & BIT_STAT_RXS));
+		*(u16 *)(drv_data->rx) = read_RDBR();
+		write_FLAG(0xFF00|chip->flag);
+		SSYNC();
+		if (chip->cs_chg_udelay)
+			udelay(chip->cs_chg_udelay);
+		drv_data->rx += 2;
+		drv_data->tx += 2;
+	}
+	write_FLAG(0xFF00);
+	SSYNC();
+}
+
+/* test if ther is more transfer to be done */
+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;
+}
+
+/* caller already set message->status; dma and pio irqs are blocked
+ * give finished message back
+ */
+static void giveback(struct driver_data *drv_data)
+{
+	struct spi_transfer *last_transfer;
+	unsigned long flags;
+	struct spi_message *msg;
+
+	spin_lock_irqsave(&drv_data->lock, flags);
+	msg = drv_data->cur_msg;
+	drv_data->cur_msg = NULL;
+	drv_data->cur_transfer = NULL;
+	drv_data->cur_chip = NULL;
+	queue_work(drv_data->workqueue, &drv_data->pump_messages);
+	spin_unlock_irqrestore(&drv_data->lock, flags);
+
+	last_transfer = list_entry(msg->transfers.prev,
+					struct spi_transfer,
+					transfer_list);
+
+	msg->state = NULL;
+	/* disable chip select signal. And not stop spi in autobuffer mode */
+	if (drv_data->tx_dma != 0xFFFF) {
+		write_FLAG(0xFF00);
+		bfin_spi_disable(drv_data);
+	}
+
+	if (msg->complete)
+		msg->complete(msg->context);
+}
+
+static irqreturn_t dma_irq_handler(int irq, void *dev_id, struct pt_regs *regs)
+{
+	struct driver_data *drv_data = (struct driver_data *)dev_id;
+	struct spi_message *msg = drv_data->cur_msg;
+
+	pr_debug("in dma_irq_handler\n");
+	clear_dma_irqstat(CH_SPI);
+
+	/* wait for the last transaction shifted out.  yes, these two
+	 * while loops are supposed to be the same (see the HRM).
+	 */
+	if (drv_data->tx != NULL) {
+		while (bfin_read_SPI_STAT() & TXS)
+			;
+		while (bfin_read_SPI_STAT() & TXS)
+			;
+	}
+
+	while (!(bfin_read_SPI_STAT() & SPIF))
+		;
+
+	bfin_spi_disable(drv_data);
+
+	msg->actual_length += drv_data->len_in_bytes;
+
+	/* Move to next transfer */
+	msg->state = next_transfer(drv_data);
+
+	/* Schedule transfer tasklet */
+	tasklet_schedule(&drv_data->pump_transfers);
+
+	/* free the irq handler before next transfer */
+	pr_debug("disable dma channel irq%d\n", CH_SPI);
+	dma_disable_irq(CH_SPI);
+
+	return IRQ_HANDLED;
+}
+
+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;
+	u16 cr, width, dma_width, dma_config;
+	u32 tranf_success = 1;
+
+	/* Get current state information */
+	message = drv_data->cur_msg;
+	transfer = drv_data->cur_transfer;
+	chip = drv_data->cur_chip;
+
+	/* if msg is error or done, report it back using complete() callback */
+	/* 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 */
+	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(drv_data);
+		return;
+	}
+
+	if (transfer->tx_buf != NULL) {
+		drv_data->tx = (void *)transfer->tx_buf;
+		drv_data->tx_end = drv_data->tx + transfer->len;
+		pr_debug("tx_buf is %p, tx_end is %p\n", transfer->tx_buf, drv_data->tx_end);
+	} else {
+		drv_data->tx = NULL;
+	}
+
+	if (transfer->rx_buf != NULL) {
+		drv_data->rx = transfer->rx_buf;
+		drv_data->rx_end = drv_data->rx + transfer->len;
+		pr_debug("rx_buf is %p, rx_end is %p\n", transfer->rx_buf, drv_data->rx_end);
+	} else {
+		drv_data->rx = NULL;
+	}
+
+	drv_data->rx_dma = transfer->rx_dma;
+	drv_data->tx_dma = transfer->tx_dma;
+	drv_data->len_in_bytes = transfer->len;
+
+	width = chip->width;
+	if (width == CFG_SPI_WORDSIZE16) {
+		drv_data->len = (transfer->len) >> 1;
+	} else {
+		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->duplex = chip->duplex ? chip->duplex : null_writer;
+	pr_debug("transfer: drv_data->write is %p, chip->write is %p, null_wr is %p\n",
+	       drv_data->write, chip->write, null_writer);
+
+	/* speed and width has been set on per message */
+
+	message->state = RUNNING_STATE;
+	dma_config = 0;
+
+	/* restore spi status for each spi transfer */
+	if (transfer->speed_hz) {
+		write_BAUD(hz_to_spi_baud(transfer->speed_hz));
+	} else {
+		write_BAUD(chip->baud);
+	}
+	write_FLAG(chip->flag);
+
+	pr_debug("now pumping a transfer: width is %d, len is %d\n",width,transfer->len);
+	/* Try to map dma buffer and do a dma transfer if successful */
+	/* use different way to r/w according to drv_data->cur_chip->enable_dma */
+	if (drv_data->cur_chip->enable_dma && drv_data->len > 6) {
+
+		write_STAT(BIT_STAT_CLR);
+		disable_dma(CH_SPI);
+		clear_dma_irqstat(CH_SPI);
+		bfin_spi_disable(drv_data);
+
+		pr_debug("doing dma transfer\n");
+		/* config dma channel */
+		if (width == CFG_SPI_WORDSIZE16) {
+			set_dma_x_count(CH_SPI, drv_data->len);
+			set_dma_x_modify(CH_SPI, 2);
+			dma_width = WDSIZE_16;
+		} else {
+			set_dma_x_count(CH_SPI, drv_data->len);
+			set_dma_x_modify(CH_SPI, 1);
+			dma_width = WDSIZE_8;
+		}
+
+		/* Go baby, go */
+		/* set transfer width,direction. And enable spi */
+		cr = (read_CTRL() & (~BIT_CTL_TIMOD));	/* clear the TIMOD bits */
+
+		/* dirty hack for autobuffer DMA mode */
+		if (drv_data->tx_dma == 0xFFFF) {
+			pr_debug("doing autobuffer DMA out.\n");
+
+			/* no irq in autobuffer mode */
+			dma_config = (DMAFLOW_AUTO | RESTART | dma_width | DI_EN);
+			set_dma_config(CH_SPI, dma_config);
+			set_dma_start_addr(CH_SPI, (unsigned long)drv_data->tx);
+			enable_dma(CH_SPI);
+			write_CTRL(cr | CFG_SPI_DMAWRITE | (width << 8) | (CFG_SPI_ENABLE << 14));
+			/* just return here, there can only be one transfer in this mode*/
+			message->status = 0;
+			giveback(drv_data);
+			return;
+		}
+
+		/* In dma mode, rx or tx must be NULL in one transfer*/
+		if (drv_data->rx != NULL) {
+			/* set transfer mode, and enable SPI */
+			pr_debug("doing DMA in.\n");
+
+			/* disable SPI before write to TDBR*/
+			write_CTRL(cr & ~BIT_CTL_ENABLE);
+
+			/* clear tx reg soformer data is not shifted out */
+			write_TDBR(0xFF);
+
+			set_dma_x_count(CH_SPI, drv_data->len);
+
+			/* start dma*/
+			dma_enable_irq(CH_SPI);
+			dma_config = (WNR | RESTART | dma_width | DI_EN);
+			set_dma_config(CH_SPI, dma_config);
+			set_dma_start_addr(CH_SPI, (unsigned long)drv_data->rx);
+			enable_dma(CH_SPI);
+
+			cr |= CFG_SPI_DMAREAD | (width << 8) | (CFG_SPI_ENABLE << 14);
+			/* set transfer mode, and enable SPI */
+			write_CTRL(cr);
+		} else if (drv_data->tx != NULL) {
+			pr_debug("doing DMA out.\n");
+			/* start dma */
+			dma_enable_irq(CH_SPI);
+			dma_config = (RESTART | dma_width | DI_EN);
+			set_dma_config(CH_SPI, dma_config);
+			set_dma_start_addr(CH_SPI, (unsigned long)drv_data->tx);
+			enable_dma(CH_SPI);
+
+			write_CTRL(cr | CFG_SPI_DMAWRITE | (width << 8) | (CFG_SPI_ENABLE << 14));
+
+		}
+	} else {		/* IO mode write then read */
+		/* Go baby, go */
+		pr_debug("doing IO transfer\n");
+
+		write_STAT(BIT_STAT_CLR);
+
+		if (drv_data->tx != NULL && drv_data->rx != NULL) { /* full duplex mode */
+			ASSERT((drv_data->tx_end - drv_data->tx) == (drv_data->rx_end - drv_data->rx));
+			cr = (read_CTRL() & (~BIT_CTL_TIMOD));	/* clear the TIMOD bits */
+			cr |= CFG_SPI_WRITE | (width << 8) | (CFG_SPI_ENABLE << 14);
+			pr_debug("IO duplex: cr is 0x%x\n", cr);
+
+			write_CTRL(cr);
+			SSYNC();
+
+			drv_data->duplex(drv_data);
+
+			if (drv_data->tx != drv_data->tx_end)
+				tranf_success = 0;
+		} else if (drv_data->tx != NULL) {        /* write only half duplex */
+			cr = (read_CTRL() & (~BIT_CTL_TIMOD));	/* clear the TIMOD bits */
+			cr |= CFG_SPI_WRITE | (width << 8) | (CFG_SPI_ENABLE << 14);
+			pr_debug("IO write: cr is 0x%x\n", cr);
+
+			write_CTRL(cr);
+			SSYNC();
+
+			drv_data->write(drv_data);
+
+			if (drv_data->tx != drv_data->tx_end)
+				tranf_success = 0;
+		} else if (drv_data->rx != NULL) {        /* read only half duplex */
+
+			cr = (read_CTRL() & (~BIT_CTL_TIMOD));	/* cleare the TIMOD bits */
+			cr |= CFG_SPI_READ | (width << 8) | (CFG_SPI_ENABLE << 14);
+			pr_debug("IO read: cr is 0x%x\n", cr);
+
+			write_CTRL(cr);
+			SSYNC();
+
+			drv_data->read(drv_data);
+			if (drv_data->rx != drv_data->rx_end)
+				tranf_success = 0;
+		}
+
+		if (!tranf_success) {
+			pr_debug("IO write error!\n");
+			message->state = ERROR_STATE;
+		} else {
+			/* Update total byte transfered */
+			message->actual_length += drv_data->len;
+
+			/* Move to next transfer of this msg*/
+			message->state = next_transfer(drv_data);
+		}
+
+		/* Schedule next transfer tasklet */
+		tasklet_schedule(&drv_data->pump_transfers);
+
+	}
+}
+
+/* pop a msg from queue and kick off real transfer */
+static void pump_messages(struct work_struct *work)
+{
+	struct driver_data *drv_data = container_of(work, struct driver_data, pump_messages);
+	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) {
+		/* pumper kicked off but no work to do */
+		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);
+
+	/* 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);
+	pr_debug("got a message to pump, state is set to: baud %d, flag 0x%x, ctl 0x%x\n",
+	       drv_data->cur_chip->baud, drv_data->cur_chip->flag, drv_data->cur_chip->ctl_reg);
+	pr_debug("the first transfer len is %d\n", drv_data->cur_transfer->len);
+
+	/* Mark as busy and launch transfers */
+	tasklet_schedule(&drv_data->pump_transfers);
+
+	drv_data->busy = 1;
+	spin_unlock_irqrestore(&drv_data->lock, flags);
+}
+
+/* got a msg to transfer, queue it in drv_data->queue. And kick off message pumper */
+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;
+
+	pr_debug("adding an msg in transfer() \n");
+	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;
+}
+
+/* first setup for new devices */
+static int setup(struct spi_device *spi)
+{
+	struct bfin5xx_spi_chip *chip_info = NULL;
+	struct chip_data *chip;
+	struct driver_data *drv_data = spi_master_get_devdata(spi->master);
+	u8 spi_flg;
+
+	if (chip_select_flag & (1 << (spi->chip_select))) {
+		printk(KERN_ERR "spi_bfin: error: %s is using the same chip selection as another device.\n", spi->modalias);
+		return -ENODEV;
+	}
+	chip_select_flag |= (1 << (spi->chip_select));
+
+	if (!spi->bits_per_word)
+		spi->bits_per_word = 16;
+
+	if (spi->bits_per_word != 8 && 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->enable_dma = 0;
+		chip_info = spi->controller_data;
+	}
+
+	/* chip_info isn't always needed */
+	if (chip_info) {
+		chip->enable_dma = chip_info->enable_dma != 0
+					&& drv_data->master_info->enable_dma;
+		chip->ctl_reg = chip_info->ctl_reg;
+		chip->bits_per_word = chip_info->bits_per_word;
+		chip->cs_change_per_word = chip_info->cs_change_per_word;
+		chip->cs_chg_udelay = chip_info->cs_chg_udelay;
+	}
+
+	if (spi->mode & SPI_CPOL)
+		chip->ctl_reg &= CPOL;
+	if (spi->mode & SPI_CPHA)
+		chip->ctl_reg &= CPHA;
+
+	/* if any one SPI chip is registered and wants DMA, request the
+	   DMA channel for it */
+	if (chip->enable_dma && !dma_requested) {
+		/* register dma irq handler */
+		if (request_dma(CH_SPI, "BF53x_SPI_DMA") < 0) {
+			pr_debug("Unable to request BlackFin SPI DMA channel\n");
+			return -ENODEV;
+		}
+		if (set_dma_callback(CH_SPI, (void *)dma_irq_handler, drv_data) < 0) {
+			pr_debug("Unable to set dma callback\n");
+			return -EPERM;
+		}
+		dma_disable_irq(CH_SPI);
+		dma_requested = 1;
+	}
+
+	/* Notice: for blackfin, the speed_hz is the value of register
+	   SPI_BAUD, not the real baudrate */
+	chip->baud = hz_to_spi_baud(spi->max_speed_hz);
+	spi_flg = ~(1 << (spi->chip_select));
+	chip->flag = ((u16)spi_flg << 8 ) | (1 << (spi->chip_select));
+	chip->chip_select_num = spi->chip_select;
+
+	if (chip->bits_per_word <= 8) {
+		chip->n_bytes = 1;
+		chip->width = CFG_SPI_WORDSIZE8;
+		chip->read = chip->cs_change_per_word? u8_cs_chg_reader: u8_reader;
+		chip->write = chip->cs_change_per_word? u8_cs_chg_writer: u8_writer;
+		chip->duplex = chip->cs_change_per_word? u8_cs_chg_duplex: u8_duplex;
+		pr_debug("8bit: chip->write is %p, u8_writer is %p\n", chip->write, u8_writer);
+	} else if (spi->bits_per_word <= 16) {
+		chip->n_bytes = 2;
+		chip->width = CFG_SPI_WORDSIZE16;
+		chip->read = chip->cs_change_per_word? u16_cs_chg_reader: u16_reader;
+		chip->write = chip->cs_change_per_word? u16_cs_chg_writer: u16_writer;
+		chip->duplex = chip->cs_change_per_word? u16_cs_chg_duplex: u16_duplex;
+		pr_debug("16bit: chip->write is %p, u16_writer is %p\n", chip->write, u16_writer);
+	} else {
+		dev_err(&spi->dev, "invalid wordsize\n");
+		kfree(chip);
+		return -ENODEV;
+	}
+	pr_debug("setup spi chip %s, width is %d, dma is %d, ctl_reg is 0x%x, flag_reg is 0x%x\n",
+	       spi->modalias, chip->width, chip->enable_dma, chip->ctl_reg, chip->flag);
+	spi_set_ctldata(spi, chip);
+
+	return 0;
+}
+
+/* callback for spi framework. clean driver specific data */
+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;
+
+	/* init transfer tasklet */
+	tasklet_init(&drv_data->pump_transfers,
+			pump_transfers,	(unsigned long)drv_data);
+
+	/* init messages workqueue */
+	INIT_WORK(&drv_data->pump_messages, pump_messages);
+	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 bfin5xx_spi_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct bfin5xx_spi_master *platform_info;
+	struct spi_master *master;
+	struct driver_data *drv_data = 0;
+	int status = 0;
+
+	platform_info = dev->platform_data;
+
+	/* 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;
+
+	/* Initial and start queue */
+	status = init_queue(drv_data);
+	if (status != 0) {
+		dev_err(&pdev->dev, "problem initializing queue\n");
+		goto out_error_queue_alloc;
+	}
+	status = start_queue(drv_data);
+	if (status != 0) {
+		dev_err(&pdev->dev, "problem starting queue\n");
+		goto out_error_queue_alloc;
+	}
+
+	/* 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;
+	}
+	pr_debug("controller probe successfully\n");
+	return status;
+
+out_error_queue_alloc:
+	destroy_queue(drv_data);
+	spi_master_put(master);
+	return status;
+}
+
+/* stop hardware and remove the driver */
+static int bfin5xx_spi_remove(struct platform_device *pdev)
+{
+	struct driver_data *drv_data = platform_get_drvdata(pdev);
+	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 */
+	bfin_spi_disable(drv_data);
+
+	/* Release DMA */
+	if (drv_data->master_info->enable_dma) {
+		if (dma_channel_active(CH_SPI))
+			free_dma(CH_SPI);
+	}
+
+	/* Disconnect from the SPI framework */
+	spi_unregister_master(drv_data->master);
+
+	/* Prevent double remove */
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+static void bfin5xx_spi_shutdown(struct platform_device *pdev)
+{
+	int status = 0;
+
+	if ((status = bfin5xx_spi_remove(pdev)) != 0)
+		dev_err(&pdev->dev, "shutdown failed with %d\n", status);
+}
+
+/* PM, do nothing now */
+#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->driver != NULL) {
+		dev_warn(dev, "pm state does not match request\n");
+		return -1;
+	}
+
+	return 0;
+}
+
+static int bfin5xx_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;
+
+	/* stop hardware */
+	bfin_spi_disable(drv_data);
+
+	return 0;
+}
+
+static int bfin5xx_spi_resume(struct platform_device *pdev)
+{
+	struct driver_data *drv_data = platform_get_drvdata(pdev);
+	int status = 0;
+
+	/* Enable the SPI interface */
+	bfin_spi_enable(drv_data);
+
+	/* 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 bfin5xx_spi_suspend NULL
+#define bfin5xx_spi_resume NULL
+#endif /* CONFIG_PM */
+
+
+static struct platform_driver driver = {
+	.driver = {
+		.name = "bfin-spi-master",
+		.bus = &platform_bus_type,
+		.owner = THIS_MODULE,
+	},
+	.probe = bfin5xx_spi_probe,
+	.remove = __devexit_p(bfin5xx_spi_remove),
+	.shutdown = bfin5xx_spi_shutdown,
+	.suspend = bfin5xx_spi_suspend,
+	.resume = bfin5xx_spi_resume,
+};
+
+static int __init bfin5xx_spi_init(void)
+{
+	platform_driver_register(&driver);
+	return 0;
+}
+module_init(bfin5xx_spi_init);
+
+static void __exit bfin5xx_spi_exit(void)
+{
+	platform_driver_unregister(&driver);
+}
+module_exit(bfin5xx_spi_exit);
_

Thanks a lot
-Bryan Wu