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-rw-r--r--drivers/spi/pxa2xx_spi.c116
-rw-r--r--drivers/spi/spi_mpc83xx.c26
-rw-r--r--drivers/spi/spi_s3c24xx.c6
3 files changed, 110 insertions, 38 deletions
diff --git a/drivers/spi/pxa2xx_spi.c b/drivers/spi/pxa2xx_spi.c
index 34c7c9875681..0e53354c1cfe 100644
--- a/drivers/spi/pxa2xx_spi.c
+++ b/drivers/spi/pxa2xx_spi.c
@@ -47,9 +47,10 @@ MODULE_ALIAS("platform:pxa2xx-spi");
#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 DMA_INT_MASK (DCSR_ENDINTR | DCSR_STARTINTR | DCSR_BUSERR)
+#define RESET_DMA_CHANNEL (DCSR_NODESC | DMA_INT_MASK)
+#define IS_DMA_ALIGNED(x) (((x) & 0x07) == 0)
+#define MAX_DMA_LEN 8191
/*
* for testing SSCR1 changes that require SSP restart, basically
@@ -144,7 +145,6 @@ struct driver_data {
size_t tx_map_len;
u8 n_bytes;
u32 dma_width;
- int cs_change;
int (*write)(struct driver_data *drv_data);
int (*read)(struct driver_data *drv_data);
irqreturn_t (*transfer_handler)(struct driver_data *drv_data);
@@ -406,8 +406,45 @@ static void giveback(struct driver_data *drv_data)
struct spi_transfer,
transfer_list);
+ /* Delay if requested before any change in chip select */
+ if (last_transfer->delay_usecs)
+ udelay(last_transfer->delay_usecs);
+
+ /* Drop chip select UNLESS cs_change is true or we are returning
+ * a message with an error, or next message is for another chip
+ */
if (!last_transfer->cs_change)
drv_data->cs_control(PXA2XX_CS_DEASSERT);
+ else {
+ struct spi_message *next_msg;
+
+ /* Holding of cs was hinted, but we need to make sure
+ * the next message is for the same chip. Don't waste
+ * time with the following tests unless this was hinted.
+ *
+ * We cannot postpone this until pump_messages, because
+ * after calling msg->complete (below) the driver that
+ * sent the current message could be unloaded, which
+ * could invalidate the cs_control() callback...
+ */
+
+ /* get a pointer to the next message, if any */
+ spin_lock_irqsave(&drv_data->lock, flags);
+ if (list_empty(&drv_data->queue))
+ next_msg = NULL;
+ else
+ next_msg = list_entry(drv_data->queue.next,
+ struct spi_message, queue);
+ spin_unlock_irqrestore(&drv_data->lock, flags);
+
+ /* see if the next and current messages point
+ * to the same chip
+ */
+ if (next_msg && next_msg->spi != msg->spi)
+ next_msg = NULL;
+ if (!next_msg || msg->state == ERROR_STATE)
+ drv_data->cs_control(PXA2XX_CS_DEASSERT);
+ }
msg->state = NULL;
if (msg->complete)
@@ -490,10 +527,9 @@ static void dma_transfer_complete(struct driver_data *drv_data)
msg->actual_length += drv_data->len -
(drv_data->rx_end - drv_data->rx);
- /* Release chip select if requested, transfer delays are
- * handled in pump_transfers */
- if (drv_data->cs_change)
- drv_data->cs_control(PXA2XX_CS_DEASSERT);
+ /* Transfer delays and chip select release are
+ * handled in pump_transfers or giveback
+ */
/* Move to next transfer */
msg->state = next_transfer(drv_data);
@@ -602,10 +638,9 @@ static void int_transfer_complete(struct driver_data *drv_data)
drv_data->cur_msg->actual_length += drv_data->len -
(drv_data->rx_end - drv_data->rx);
- /* Release chip select if requested, transfer delays are
- * handled in pump_transfers */
- if (drv_data->cs_change)
- drv_data->cs_control(PXA2XX_CS_DEASSERT);
+ /* Transfer delays and chip select release are
+ * handled in pump_transfers or giveback
+ */
/* Move to next transfer */
drv_data->cur_msg->state = next_transfer(drv_data);
@@ -840,23 +875,40 @@ static void pump_transfers(unsigned long data)
return;
}
- /* Delay if requested at end of transfer*/
+ /* Delay if requested at end of transfer before CS change */
if (message->state == RUNNING_STATE) {
previous = list_entry(transfer->transfer_list.prev,
struct spi_transfer,
transfer_list);
if (previous->delay_usecs)
udelay(previous->delay_usecs);
+
+ /* Drop chip select only if cs_change is requested */
+ if (previous->cs_change)
+ drv_data->cs_control(PXA2XX_CS_DEASSERT);
}
- /* Check transfer length */
- if (transfer->len > 8191)
- {
- dev_warn(&drv_data->pdev->dev, "pump_transfers: transfer "
- "length greater than 8191\n");
- message->status = -EINVAL;
- giveback(drv_data);
- return;
+ /* Check for transfers that need multiple DMA segments */
+ if (transfer->len > MAX_DMA_LEN && chip->enable_dma) {
+
+ /* reject already-mapped transfers; PIO won't always work */
+ if (message->is_dma_mapped
+ || transfer->rx_dma || transfer->tx_dma) {
+ dev_err(&drv_data->pdev->dev,
+ "pump_transfers: mapped transfer length "
+ "of %lu is greater than %d\n",
+ transfer->len, MAX_DMA_LEN);
+ message->status = -EINVAL;
+ giveback(drv_data);
+ return;
+ }
+
+ /* warn ... we force this to PIO mode */
+ if (printk_ratelimit())
+ dev_warn(&message->spi->dev, "pump_transfers: "
+ "DMA disabled for transfer length %ld "
+ "greater than %d\n",
+ (long)drv_data->len, MAX_DMA_LEN);
}
/* Setup the transfer state based on the type of transfer */
@@ -878,7 +930,6 @@ static void pump_transfers(unsigned long data)
drv_data->len = transfer->len & DCMD_LENGTH;
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;
/* Change speed and bit per word on a per transfer */
cr0 = chip->cr0;
@@ -925,7 +976,7 @@ static void pump_transfers(unsigned long data)
&dma_thresh))
if (printk_ratelimit())
dev_warn(&message->spi->dev,
- "pump_transfer: "
+ "pump_transfers: "
"DMA burst size reduced to "
"match bits_per_word\n");
}
@@ -939,8 +990,23 @@ static void pump_transfers(unsigned long data)
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))) {
+ /* Try to map dma buffer and do a dma transfer if successful, but
+ * only if the length is non-zero and less than MAX_DMA_LEN.
+ *
+ * Zero-length non-descriptor DMA is illegal on PXA2xx; force use
+ * of PIO instead. Care is needed above because the transfer may
+ * have have been passed with buffers that are already dma mapped.
+ * A zero-length transfer in PIO mode will not try to write/read
+ * to/from the buffers
+ *
+ * REVISIT large transfers are exactly where we most want to be
+ * using DMA. If this happens much, split those transfers into
+ * multiple DMA segments rather than forcing PIO.
+ */
+ drv_data->dma_mapped = 0;
+ if (drv_data->len > 0 && drv_data->len <= MAX_DMA_LEN)
+ drv_data->dma_mapped = map_dma_buffers(drv_data);
+ if (drv_data->dma_mapped) {
/* Ensure we have the correct interrupt handler */
drv_data->transfer_handler = dma_transfer;
diff --git a/drivers/spi/spi_mpc83xx.c b/drivers/spi/spi_mpc83xx.c
index 070c6219e2d6..ac0e3e4b3c54 100644
--- a/drivers/spi/spi_mpc83xx.c
+++ b/drivers/spi/spi_mpc83xx.c
@@ -267,16 +267,13 @@ int mpc83xx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
cs->hw_mode |= SPMODE_LEN(bits_per_word);
if ((mpc83xx_spi->spibrg / hz) > 64) {
+ cs->hw_mode |= SPMODE_DIV16;
pm = mpc83xx_spi->spibrg / (hz * 64);
if (pm > 16) {
- cs->hw_mode |= SPMODE_DIV16;
- pm /= 16;
- if (pm > 16) {
- dev_err(&spi->dev, "Requested speed is too "
- "low: %d Hz. Will use %d Hz instead.\n",
- hz, mpc83xx_spi->spibrg / 1024);
- pm = 16;
- }
+ dev_err(&spi->dev, "Requested speed is too "
+ "low: %d Hz. Will use %d Hz instead.\n",
+ hz, mpc83xx_spi->spibrg / 1024);
+ pm = 16;
}
} else
pm = mpc83xx_spi->spibrg / (hz * 4);
@@ -315,11 +312,20 @@ static int mpc83xx_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
if (t->bits_per_word)
bits_per_word = t->bits_per_word;
len = t->len;
- if (bits_per_word > 8)
+ if (bits_per_word > 8) {
+ /* invalid length? */
+ if (len & 1)
+ return -EINVAL;
len /= 2;
- if (bits_per_word > 16)
+ }
+ if (bits_per_word > 16) {
+ /* invalid length? */
+ if (len & 1)
+ return -EINVAL;
len /= 2;
+ }
mpc83xx_spi->count = len;
+
INIT_COMPLETION(mpc83xx_spi->done);
/* enable rx ints */
diff --git a/drivers/spi/spi_s3c24xx.c b/drivers/spi/spi_s3c24xx.c
index 98abc73c1a1d..3eb414b84a9d 100644
--- a/drivers/spi/spi_s3c24xx.c
+++ b/drivers/spi/spi_s3c24xx.c
@@ -430,7 +430,7 @@ static int s3c24xx_spi_resume(struct platform_device *pdev)
#endif
MODULE_ALIAS("platform:s3c2410-spi");
-static struct platform_driver s3c24xx_spidrv = {
+static struct platform_driver s3c24xx_spi_driver = {
.remove = __exit_p(s3c24xx_spi_remove),
.suspend = s3c24xx_spi_suspend,
.resume = s3c24xx_spi_resume,
@@ -442,12 +442,12 @@ static struct platform_driver s3c24xx_spidrv = {
static int __init s3c24xx_spi_init(void)
{
- return platform_driver_probe(&s3c24xx_spidrv, s3c24xx_spi_probe);
+ return platform_driver_probe(&s3c24xx_spi_driver, s3c24xx_spi_probe);
}
static void __exit s3c24xx_spi_exit(void)
{
- platform_driver_unregister(&s3c24xx_spidrv);
+ platform_driver_unregister(&s3c24xx_spi_driver);
}
module_init(s3c24xx_spi_init);
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