spi: fix freeze issue when spi transferring special length of data

Fix DMA mode will freeze when transfering
8 bytes/8 bits,16 bytes/16 bits, 32 bytes/32 bits.
and enable DMA mode in spi transferring.

Cherry-pick from:
https://github.com/01org/edison-linux/commit/2d7dacd26d06afec9fd4d7a5df73bc4f77571195

Signed-off-by: Shimin Zhou <shimingx.zhou@intel.com>
Signed-off-by: Zhenming Zhao <zhenmingx.zhao@intel.com>
BUG=26065307
Change-Id: I851219a761b6c65cd7a8edc1370c054ce6c35883

3 files changed, 14 insertions, 22 deletions

diff --git a/arch/x86/platform/intel-mid/device_libs/platform_spidev.c b/arch/x86/platform/intel-mid/device_libs/platform_spidev.c
index cc7512943a2..40827d64011 100644
--- a/arch/x86/platform/intel-mid/device_libs/platform_spidev.c
+++ b/arch/x86/platform/intel-mid/device_libs/platform_spidev.c
@@ -26,7 +26,7 @@ static struct intel_mid_ssp_spi_chip chip = {
 	.burst_size = DFLT_FIFO_BURST_SIZE,
 	.timeout = DFLT_TIMEOUT_VAL,
 	/* SPI DMA is currently usable on Tangier */
-	.dma_enabled = false,
+	.dma_enabled = true,
 	.cs_control = tng_ssp_spi_cs_control,
 	.platform_pinmux = tng_ssp_spi_platform_pinmux,
 };
diff --git a/drivers/spi/intel_mid_ssp_spi.c b/drivers/spi/intel_mid_ssp_spi.c
index 0ccffed4af5..f68691082f9 100644
--- a/drivers/spi/intel_mid_ssp_spi.c
+++ b/drivers/spi/intel_mid_ssp_spi.c
@@ -544,7 +544,7 @@ static void dma_transfer(struct ssp_drv_context *sspc)
 
 		/* In Rx direction, TRAIL Bytes are handled by memcpy */
 		if (sspc->rx_dma &&
-			(sspc->len_dma_rx >
+			(sspc->len_dma_rx >=
 				sspc->rx_fifo_threshold * sspc->n_bytes))
 		{
 			sspc->len_dma_rx = TRUNCATE(sspc->len_dma_rx,
@@ -961,7 +961,6 @@ static int handle_message(struct ssp_drv_context *sspc)
 	u32 mask = 0;
 	int bits_per_word, saved_bits_per_word;
 	unsigned long flags;
-	u8 normal_enabled = 0;
 
 	chip = spi_get_ctldata(msg->spi);
 
@@ -1056,28 +1055,16 @@ static int handle_message(struct ssp_drv_context *sspc)
 			sspc->n_bytes = 1;
 			sspc->read = u8_reader;
 			sspc->write = u8_writer;
-			/* It maybe has some unclear issue in dma mode, as workaround,
-			use normal mode to transfer when len equal 8 bytes */
-			if (transfer->len == 8)
-				normal_enabled = 1;
 		} else if (bits_per_word <= 16) {
 			sspc->n_bytes = 2;
 			sspc->read = u16_reader;
 			sspc->write = u16_writer;
-			/* It maybe has some unclear issue in dma mode, as workaround,
-			use normal mode to transfer when len equal 16 bytes */
-			if (transfer->len == 16)
-				normal_enabled = 1;
 		} else if (bits_per_word <= 32) {
 			if (!ssp_timing_wr)
 				cr0 |= SSCR0_EDSS;
 			sspc->n_bytes = 4;
 			sspc->read = u32_reader;
 			sspc->write = u32_writer;
-			/* It maybe has some unclear issue in dma mode, as workaround,
-			use normal mode to transfer when len equal 32 bytes */
-			if (transfer->len == 32)
-				normal_enabled = 1;
 		}
 
 		sspc->tx  = (void *)transfer->tx_buf;
@@ -1116,7 +1103,7 @@ static int handle_message(struct ssp_drv_context *sspc)
 			/* value. The RX fifo threshold must be aligned with the DMA */
 			/* RX transfer size, which may be limited to a multiple of 4 */
 			/* bytes due to 32bits DDR access.                           */
-			if  (sspc->len / sspc->n_bytes <= sspc->rx_fifo_threshold) {
+			if  (sspc->len / sspc->n_bytes < sspc->rx_fifo_threshold) {
 				u32 rx_fifo_threshold;
 
 				rx_fifo_threshold = (sspc->len & ~(4 - 1)) /
@@ -1178,7 +1165,7 @@ static int handle_message(struct ssp_drv_context *sspc)
 		if (sspc->cs_control)
 			sspc->cs_control(sspc->cs_assert);
 
-		if (likely(dma_enabled) && (!normal_enabled)) {
+		if (likely(dma_enabled)) {
 			if (unlikely(sspc->quirks & QUIRKS_USE_PM_QOS))
 				pm_qos_update_request(&sspc->pm_qos_req,
 						MIN_EXIT_LATENCY);
@@ -1255,10 +1242,11 @@ static int setup(struct spi_device *spi)
 	if (!spi->bits_per_word)
 		spi->bits_per_word = DFLT_BITS_PER_WORD;
 
-	if ((spi->bits_per_word < MIN_BITS_PER_WORD
-		|| spi->bits_per_word > MAX_BITS_PER_WORD)) {
-		ret = -EINVAL;
-		goto exit_setup;
+	if ((spi->bits_per_word != 8) && (spi->bits_per_word != 16)
+		&& (spi->bits_per_word != 32)) {
+		spin_unlock_irqrestore(&sspc->lock, flags);
+		dev_warn(&spi->dev, "invalid wordsize, system only support 8,16,32 bits per word.\n");
+		return -EINVAL;
 	}
 
 	chip = spi_get_ctldata(spi);
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index a08f923b992..12112a1f3ed 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -438,7 +438,8 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		break;
 
 	default:
-		/* segmented and/or full-duplex I/O request */
+		/* segmented and/or full-duplex I/O request.
+		   Note: Maximum support 511 n_ioc at a time */
 		if (_IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0))
 				|| _IOC_DIR(cmd) != _IOC_WRITE) {
 			retval = -ENOTTY;
@@ -452,7 +453,10 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		}
 		n_ioc = tmp / sizeof(struct spi_ioc_transfer);
 		if (n_ioc == 0)
+		{
+			dev_err(&spi->dev, "Value of n_ioc is out of range( 1 ~ 511 ).\n");
 			break;
+		}
 
 		/* copy into scratch area */
 		ioc = kmalloc(tmp, GFP_KERNEL);