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Subject[PATCH] spi: Code Review Updated PXA2xx SSP SPI Driver
From
Date
Attached is an updated patch to add a SPI master controller for PXA2xx
boards. This update includes changes suggested by Andrew Morton and
Nicolas Pitre. Thank you for the through review:)

Any additional feedback or word of success would be greatly appreciated!

Stephen

This driver turns a PXA2xx synchronous serial port (SSP) into a SPI master
controller (see Documentation/spi/spi_summary). The driver has the following
features:

- Support for any PXA2xx SSP
- SSP PIO and SSP DMA data transfers.
- External and Internal (SSPFRM) chip selects.
- Per slave device (chip) configuration.
- Full suspend, freeze, resume support.

Signed-off-by: Stephen Street <stephen@streetfiresound.com>
---

Documentation/spi/pxa2xx | 234 +++++
drivers/spi/Kconfig | 8
drivers/spi/Makefile | 1
drivers/spi/pxa2xx_spi.c | 1399 ++++++++++++++++++++++++++++++++++
include/asm-arm/arch-pxa/pxa2xx_spi.h | 68 +
5 files changed, 1710 insertions(+)

--- linux-2.6.16-rc2/drivers/spi/Kconfig 2006-02-13 17:05:10.423080731 -0800
+++ linux-spi/drivers/spi/Kconfig 2006-02-13 17:05:23.151062669 -0800
@@ -85,6 +85,14 @@ config SPI_BUTTERFLY
inexpensive battery powered microcontroller evaluation board.
This same cable can be used to flash new firmware.

+config SPI_PXA2XX
+ tristate "PXA2xx SSP SPI master"
+ depends on SPI_MASTER && ARCH_PXA && EXPERIMENTAL
+ help
+ This enables using a PXA2xx SSP port as a SPI master controller.
+ The driver can be configured to use any SSP port and additional
+ documentation can be found a Documentation/spi/pxa2xx.
+
#
# Add new SPI master controllers in alphabetical order above this line
#
--- linux-2.6.16-rc2/drivers/spi/Makefile 2006-02-13 17:05:10.424080730 -0800
+++ linux-spi/drivers/spi/Makefile 2006-02-13 17:05:23.168062643 -0800
@@ -13,6 +13,7 @@ obj-$(CONFIG_SPI_MASTER) += spi.o
# SPI master controller drivers (bus)
obj-$(CONFIG_SPI_BITBANG) += spi_bitbang.o
obj-$(CONFIG_SPI_BUTTERFLY) += spi_butterfly.o
+obj-$(CONFIG_SPI_PXA2XX) += pxa2xx_spi.o
# ... add above this line ...

# SPI protocol drivers (device/link on bus)
--- linux-2.6.16-rc2/drivers/spi/pxa2xx_spi.c 1969-12-31 16:00:00.000000000 -0800
+++ linux-spi/drivers/spi/pxa2xx_spi.c 2006-02-13 17:05:23.178062627 -0800
@@ -0,0 +1,1399 @@
+/*
+ * 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);
--- linux-2.6.16-rc2/include/asm-arm/arch-pxa/pxa2xx_spi.h 1969-12-31 16:00:00.000000000 -0800
+++ linux-spi/include/asm-arm/arch-pxa/pxa2xx_spi.h 2006-02-13 17:05:23.186062615 -0800
@@ -0,0 +1,68 @@
+/*
+ * 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.
+ */
+
+#ifndef PXA2XX_SPI_H_
+#define PXA2XX_SPI_H_
+
+#define PXA2XX_CS_ASSERT (0x01)
+#define PXA2XX_CS_DEASSERT (0x02)
+
+#if defined(CONFIG_PXA25x)
+#define CLOCK_SPEED_HZ 3686400
+#define SSP1_SerClkDiv(x) (((CLOCK_SPEED_HZ/2/(x+1))<<8)&0x0000ff00)
+#define SSP2_SerClkDiv(x) (((CLOCK_SPEED_HZ/(x+1))<<8)&0x000fff00)
+#define SSP3_SerClkDiv(x) (((CLOCK_SPEED_HZ/(x+1))<<8)&0x000fff00)
+#elif defined(CONFIG_PXA27x)
+#define CLOCK_SPEED_HZ 13000000
+#define SSP1_SerClkDiv(x) (((CLOCK_SPEED_HZ/(x+1))<<8)&0x000fff00)
+#define SSP2_SerClkDiv(x) (((CLOCK_SPEED_HZ/(x+1))<<8)&0x000fff00)
+#define SSP3_SerClkDiv(x) (((CLOCK_SPEED_HZ/(x+1))<<8)&0x000fff00)
+#endif
+
+#define SSP1_VIRT ((void *)(io_p2v(__PREG(SSCR0_P(1)))))
+#define SSP2_VIRT ((void *)(io_p2v(__PREG(SSCR0_P(2)))))
+#define SSP3_VIRT ((void *)(io_p2v(__PREG(SSCR0_P(3)))))
+
+enum pxa_ssp_type {
+ SSP_UNDEFINED = 0,
+ PXA25x_SSP, /* pxa 210, 250, 255, 26x */
+ PXA25x_NSSP, /* pxa 255, 26x (including ASSP) */
+ PXA27x_SSP,
+};
+
+/* device.platform_data for SSP controller devices */
+struct pxa2xx_spi_master {
+ enum pxa_ssp_type ssp_type;
+ u32 clock_enable;
+ u16 num_chipselect;
+ u8 enable_dma;
+};
+
+/* spi_board_info.controller_data for SPI slave devices,
+ * copied to spi_device.platform_data ... mostly for dma tuning
+ */
+struct pxa2xx_spi_chip {
+ u8 tx_threshold;
+ u8 rx_threshold;
+ u8 dma_burst_size;
+ u32 timeout_microsecs;
+ u8 enable_loopback;
+ void (*cs_control)(u32 command);
+};
+
+#endif /*PXA2XX_SPI_H_*/
--- linux-2.6.16-rc2/Documentation/spi/pxa2xx 1969-12-31 16:00:00.000000000 -0800
+++ linux-spi/Documentation/spi/pxa2xx 2006-02-13 17:05:23.203062588 -0800
@@ -0,0 +1,234 @@
+PXA2xx SPI on SSP driver HOWTO
+===================================================
+This a mini howto on the pxa2xx_spi driver. The driver turns a PXA2xx
+synchronous serial port into a SPI master controller
+(see Documentation/spi/spi_summary). The driver has the following features
+
+- Support for any PXA2xx SSP
+- SSP PIO and SSP DMA data transfers.
+- External and Internal (SSPFRM) chip selects.
+- Per slave device (chip) configuration.
+- Full suspend, freeze, resume support.
+
+The driver is built around a "spi_message" fifo serviced by workqueue and a
+tasklet. The workqueue, "pump_messages", drives message fifo and the tasklet
+(pump_transfer) is responsible for queuing SPI transactions and setting up and
+launching the dma/interrupt driven transfers.
+
+Declaring PXA2xx Master Controllers
+-----------------------------------
+Typically a SPI master is defined in the arch/.../mach-*/board-*.c as a
+"platform device". The master configuration is passed to the driver via a table
+found in include/asm-arm/arch-pxa/pxa2xx_spi.h:
+
+struct pxa2xx_spi_master {
+ enum pxa_ssp_type ssp_type;
+ u32 clock_enable;
+ u16 num_chipselect;
+ u8 enable_dma;
+};
+
+The "pxa2xx_spi_master.ssp_type" field must have a value between 1 and 3 and
+informs the driver which features a particular SSP supports.
+
+The "pxa2xx_spi_master.clock_enable" field is used to enable/disable the
+corresponding SSP peripheral block in the "Clock Enable Register (CKEN"). See
+the "PXA2xx Developer Manual" section "Clocks and Power Management".
+
+The "pxa2xx_spi_master.num_chipselect" field is used to determine the number of
+slave device (chips) attached to this SPI master.
+
+The "pxa2xx_spi_master.enable_dma" field informs the driver that SSP DMA should
+be used. This caused the driver to acquire two DMA channels: rx_channel and
+tx_channel. The rx_channel has a higher DMA service priority the tx_channel.
+See the "PXA2xx Developer Manual" section "DMA Controller".
+
+NSSP MASTER SAMPLE
+------------------
+Below is a sample configuration using the PXA255 NSSP.
+
+static struct resource pxa_spi_nssp_resources[] = {
+ [0] = {
+ .start = __PREG(SSCR0_P(2)), /* Start address of NSSP */
+ .end = __PREG(SSCR0_P(2)) + 0x2c, /* Range of registers */
+ .flags = IORESOURCE_MEM,
+ },
+ [1] = {
+ .start = IRQ_NSSP, /* NSSP IRQ */
+ .end = IRQ_NSSP,
+ .flags = IORESOURCE_IRQ,
+ },
+};
+
+static struct pxa2xx_spi_master pxa_nssp_master_info = {
+ .ssp_type = PXA25x_NSSP, /* Type of SSP */
+ .clock_enable = CKEN9_NSSP, /* NSSP Peripheral clock */
+ .num_chipselect = 1, /* Matches the number of chips attached to NSSP */
+ .enable_dma = 1, /* Enables NSSP DMA */
+};
+
+static struct platform_device pxa_spi_nssp = {
+ .name = "pxa2xx-spi", /* MUST BE THIS VALUE, so device match driver */
+ .id = 2, /* Bus number, MUST MATCH SSP number 1..n */
+ .resource = pxa_spi_nssp_resources,
+ .num_resources = ARRAY_SIZE(pxa_spi_nssp_resources),
+ .dev = {
+ .platform_data = &pxa_nssp_master_info, /* Passed to driver */
+ },
+};
+
+static struct platform_device *devices[] __initdata = {
+ &pxa_spi_nssp,
+};
+
+static void __init board_init(void)
+{
+ (void)platform_add_device(devices, ARRAY_SIZE(devices));
+}
+
+Declaring Slave Devices
+-----------------------
+Typically each SPI slave (chip) is defined in the arch/.../mach-*/board-*.c
+using the "spi_board_info" structure found in "linux/spi/spi.h". See
+"Documentation/spi/spi_summary" for additional information.
+
+Each slave device attached to the PXA must provide slave specific configuration
+information via the structure "pxa2xx_spi_chip" found in
+"include/asm-arm/arch-pxa/pxa2xx_spi.h". The pxa2xx_spi master controller driver
+will uses the configuration whenever the driver communicates with the slave
+device.
+
+struct pxa2xx_spi_chip {
+ u8 tx_threshold;
+ u8 rx_threshold;
+ u8 dma_burst_size;
+ u32 timeout_microsecs;
+ u8 enable_loopback;
+ void (*cs_control)(u32 command);
+};
+
+The "pxa2xx_spi_chip.tx_threshold" and "pxa2xx_spi_chip.rx_threshold" fields are
+used to configure the SSP hardware fifo. These fields are critical to the
+performance of pxa2xx_spi driver and misconfiguration will result in rx
+fifo overruns (especially in PIO mode transfers). Good default values are
+
+ .tx_threshold = 12,
+ .rx_threshold = 4,
+
+The "pxa2xx_spi_chip.dma_burst_size" field is used to configure PXA2xx DMA
+engine and is related the "spi_device.bits_per_word" field. Read and understand
+the PXA2xx "Developer Manual" sections on the DMA controller and SSP Controllers
+to determine the correct value. An SSP configured for byte-wide transfers would
+use a value of 8.
+
+The "pxa2xx_spi_chip.timeout_microsecs" fields is used to efficiently handle
+trailing bytes in the SSP receiver fifo. The correct value for this field is
+dependent on the SPI bus speed ("spi_board_info.max_speed_hz") and the specific
+slave device. Please note the the PXA2xx SSP 1 does not support trailing byte
+timeouts and must busy-wait any trailing bytes.
+
+The "pxa2xx_spi_chip.enable_loopback" field is used to place the SSP porting
+into internal loopback mode. In this mode the SSP controller internally
+connects the SSPTX pin the the SSPRX pin. This is useful for initial setup
+testing.
+
+The "pxa2xx_spi_chip.cs_control" field is used to point to a board specific
+function for asserting/deasserting a slave device chip select. If the field is
+NULL, the pxa2xx_spi master controller driver assumes that the SSP port is
+configured to use SSPFRM instead.
+
+NSSP SALVE SAMPLE
+-----------------
+The pxa2xx_spi_chip structure is passed to the pxa2xx_spi driver in the
+"spi_board_info.controller_data" field. Below is a sample configuration using
+the PXA255 NSSP.
+
+/* Chip Select control for the CS8415A SPI slave device */
+static void cs8415a_cs_control(u32 command)
+{
+ if (command & PXA2XX_CS_ASSERT)
+ GPCR(2) = GPIO_bit(2);
+ else
+ GPSR(2) = GPIO_bit(2);
+}
+
+/* Chip Select control for the CS8405A SPI slave device */
+static void cs8405a_cs_control(u32 command)
+{
+ if (command & PXA2XX_CS_ASSERT)
+ GPCR(3) = GPIO_bit(3);
+ else
+ GPSR(3) = GPIO_bit(3);
+}
+
+static struct pxa2xx_spi_chip cs8415a_chip_info = {
+ .tx_threshold = 12, /* SSP hardward FIFO threshold */
+ .rx_threshold = 4, /* SSP hardward FIFO threshold */
+ .dma_burst_size = 8, /* Byte wide transfers used so 8 byte bursts */
+ .timeout_microsecs = 64, /* Wait at least 64usec to handle trailing */
+ .cs_control = cs8415a_cs_control, /* Use external chip select */
+};
+
+static struct pxa2xx_spi_chip cs8405a_chip_info = {
+ .tx_threshold = 12, /* SSP hardward FIFO threshold */
+ .rx_threshold = 4, /* SSP hardward FIFO threshold */
+ .dma_burst_size = 8, /* Byte wide transfers used so 8 byte bursts */
+ .timeout_microsecs = 64, /* Wait at least 64usec to handle trailing */
+ .cs_control = cs8405a_cs_control, /* Use external chip select */
+};
+
+static struct spi_board_info streetracer_spi_board_info[] __initdata = {
+ {
+ .modalias = "cs8415a", /* Name of spi_driver for this device */
+ .max_speed_hz = 3686400, /* Run SSP as fast a possbile */
+ .bus_num = 2, /* Framework bus number */
+ .chip_select = 0, /* Framework chip select */
+ .platform_data = NULL; /* No spi_driver specific config */
+ .controller_data = &cs8415a_chip_info, /* Master chip config */
+ .irq = STREETRACER_APCI_IRQ, /* Slave device interrupt */
+ },
+ {
+ .modalias = "cs8405a", /* Name of spi_driver for this device */
+ .max_speed_hz = 3686400, /* Run SSP as fast a possbile */
+ .bus_num = 2, /* Framework bus number */
+ .chip_select = 1, /* Framework chip select */
+ .controller_data = &cs8405a_chip_info, /* Master chip config */
+ .irq = STREETRACER_APCI_IRQ, /* Slave device interrupt */
+ },
+};
+
+static void __init streetracer_init(void)
+{
+ spi_register_board_info(streetracer_spi_board_info,
+ ARRAY_SIZE(streetracer_spi_board_info));
+}
+
+
+DMA and PIO I/O Support
+-----------------------
+The pxa2xx_spi driver support both DMA and interrupt driven PIO message
+transfers. The driver defaults to PIO mode and DMA transfers must enabled by
+setting the "enable_dma" flag in the "pxa2xx_spi_master" structure and and
+ensuring that the "pxa2xx_spi_chip.dma_burst_size" field is non-zero. The DMA
+mode support both coherent and stream based DMA mappings.
+
+The following logic is used to determine the type of I/O to be used on
+a per "spi_transfer" basis:
+
+if !enable_dma or dma_burst_size == 0 then
+ always use PIO transfers
+
+if spi_message.is_dma_mapped and rx_dma_buf != 0 and tx_dma_buf != 0 then
+ use coherent DMA mode
+
+if rx_buf and tx_buf are aligned on 8 byte boundary then
+ use streaming DMA mode
+
+otherwise
+ use PIO transfer
+
+THANKS TO
+---------
+
+David Brownell and others for mentoring the development of this driver.
+
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