Merge branch 'next' (accumulated 3.16 merge window patches) into master

Now that 3.15 is released, this merges the 'next' branch into 'master',
bringing us to the normal situation where my 'master' branch is the
merge window.

* accumulated work in next: (6809 commits)
  ufs: sb mutex merge + mutex_destroy
  powerpc: update comments for generic idle conversion
  cris: update comments for generic idle conversion
  idle: remove cpu_idle() forward declarations
  nbd: zero from and len fields in NBD_CMD_DISCONNECT.
  mm: convert some level-less printks to pr_*
  MAINTAINERS: adi-buildroot-devel is moderated
  MAINTAINERS: add linux-api for review of API/ABI changes
  mm/kmemleak-test.c: use pr_fmt for logging
  fs/dlm/debug_fs.c: replace seq_printf by seq_puts
  fs/dlm/lockspace.c: convert simple_str to kstr
  fs/dlm/config.c: convert simple_str to kstr
  mm: mark remap_file_pages() syscall as deprecated
  mm: memcontrol: remove unnecessary memcg argument from soft limit functions
  mm: memcontrol: clean up memcg zoneinfo lookup
  mm/memblock.c: call kmemleak directly from memblock_(alloc|free)
  mm/mempool.c: update the kmemleak stack trace for mempool allocations
  lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations
  mm: introduce kmemleak_update_trace()
  mm/kmemleak.c: use %u to print ->checksum
  ...

1 files changed, 217 insertions, 384 deletions

diff --git a/drivers/spi/spi-rspi.c b/drivers/spi/spi-rspi.c
index 1fb0ad213324..10112745bb17 100644
--- a/drivers/spi/spi-rspi.c
+++ b/drivers/spi/spi-rspi.c
@@ -183,8 +183,6 @@
 #define SPBFCR_TXTRG_MASK	0x30	/* Transmit Buffer Data Triggering Number */
 #define SPBFCR_RXTRG_MASK	0x07	/* Receive Buffer Data Triggering Number */
 
-#define DUMMY_DATA		0x00
-
 struct rspi_data {
 	void __iomem *addr;
 	u32 max_speed_hz;
@@ -197,11 +195,6 @@ struct rspi_data {
 	int rx_irq, tx_irq;
 	const struct spi_ops *ops;
 
-	/* for dmaengine */
-	struct dma_chan *chan_tx;
-	struct dma_chan *chan_rx;
-
-	unsigned dma_width_16bit:1;
 	unsigned dma_callbacked:1;
 	unsigned byte_access:1;
 };
@@ -253,6 +246,8 @@ struct spi_ops {
 	int (*transfer_one)(struct spi_master *master, struct spi_device *spi,
 			    struct spi_transfer *xfer);
 	u16 mode_bits;
+	u16 flags;
+	u16 fifo_size;
 };
 
 /*
@@ -266,7 +261,8 @@ static int rspi_set_config_register(struct rspi_data *rspi, int access_size)
 	rspi_write8(rspi, rspi->sppcr, RSPI_SPPCR);
 
 	/* Sets transfer bit rate */
-	spbr = clk_get_rate(rspi->clk) / (2 * rspi->max_speed_hz) - 1;
+	spbr = DIV_ROUND_UP(clk_get_rate(rspi->clk),
+			    2 * rspi->max_speed_hz) - 1;
 	rspi_write8(rspi, clamp(spbr, 0, 255), RSPI_SPBR);
 
 	/* Disable dummy transmission, set 16-bit word access, 1 frame */
@@ -302,7 +298,8 @@ static int rspi_rz_set_config_register(struct rspi_data *rspi, int access_size)
 	rspi_write8(rspi, rspi->sppcr, RSPI_SPPCR);
 
 	/* Sets transfer bit rate */
-	spbr = clk_get_rate(rspi->clk) / (2 * rspi->max_speed_hz) - 1;
+	spbr = DIV_ROUND_UP(clk_get_rate(rspi->clk),
+			    2 * rspi->max_speed_hz) - 1;
 	rspi_write8(rspi, clamp(spbr, 0, 255), RSPI_SPBR);
 
 	/* Disable dummy transmission, set byte access */
@@ -335,7 +332,7 @@ static int qspi_set_config_register(struct rspi_data *rspi, int access_size)
 	rspi_write8(rspi, rspi->sppcr, RSPI_SPPCR);
 
 	/* Sets transfer bit rate */
-	spbr = clk_get_rate(rspi->clk) / (2 * rspi->max_speed_hz);
+	spbr = DIV_ROUND_UP(clk_get_rate(rspi->clk), 2 * rspi->max_speed_hz);
 	rspi_write8(rspi, clamp(spbr, 0, 255), RSPI_SPBR);
 
 	/* Disable dummy transmission, set byte access */
@@ -403,11 +400,22 @@ static int rspi_wait_for_interrupt(struct rspi_data *rspi, u8 wait_mask,
 	return 0;
 }
 
+static inline int rspi_wait_for_tx_empty(struct rspi_data *rspi)
+{
+	return rspi_wait_for_interrupt(rspi, SPSR_SPTEF, SPCR_SPTIE);
+}
+
+static inline int rspi_wait_for_rx_full(struct rspi_data *rspi)
+{
+	return rspi_wait_for_interrupt(rspi, SPSR_SPRF, SPCR_SPRIE);
+}
+
 static int rspi_data_out(struct rspi_data *rspi, u8 data)
 {
-	if (rspi_wait_for_interrupt(rspi, SPSR_SPTEF, SPCR_SPTIE) < 0) {
+	int error = rspi_wait_for_tx_empty(rspi);
+	if (error < 0) {
 		dev_err(&rspi->master->dev, "transmit timeout\n");
-		return -ETIMEDOUT;
+		return error;
 	}
 	rspi_write_data(rspi, data);
 	return 0;
@@ -415,25 +423,36 @@ static int rspi_data_out(struct rspi_data *rspi, u8 data)
 
 static int rspi_data_in(struct rspi_data *rspi)
 {
+	int error;
 	u8 data;
 
-	if (rspi_wait_for_interrupt(rspi, SPSR_SPRF, SPCR_SPRIE) < 0) {
+	error = rspi_wait_for_rx_full(rspi);
+	if (error < 0) {
 		dev_err(&rspi->master->dev, "receive timeout\n");
-		return -ETIMEDOUT;
+		return error;
 	}
 	data = rspi_read_data(rspi);
 	return data;
 }
 
-static int rspi_data_out_in(struct rspi_data *rspi, u8 data)
+static int rspi_pio_transfer(struct rspi_data *rspi, const u8 *tx, u8 *rx,
+			     unsigned int n)
 {
-	int ret;
-
-	ret = rspi_data_out(rspi, data);
-	if (ret < 0)
-		return ret;
+	while (n-- > 0) {
+		if (tx) {
+			int ret = rspi_data_out(rspi, *tx++);
+			if (ret < 0)
+				return ret;
+		}
+		if (rx) {
+			int ret = rspi_data_in(rspi);
+			if (ret < 0)
+				return ret;
+			*rx++ = ret;
+		}
+	}
 
-	return rspi_data_in(rspi);
+	return 0;
 }
 
 static void rspi_dma_complete(void *arg)
@@ -444,97 +463,67 @@ static void rspi_dma_complete(void *arg)
 	wake_up_interruptible(&rspi->wait);
 }
 
-static int rspi_dma_map_sg(struct scatterlist *sg, const void *buf,
-			   unsigned len, struct dma_chan *chan,
-			   enum dma_transfer_direction dir)
-{
-	sg_init_table(sg, 1);
-	sg_set_buf(sg, buf, len);
-	sg_dma_len(sg) = len;
-	return dma_map_sg(chan->device->dev, sg, 1, dir);
-}
-
-static void rspi_dma_unmap_sg(struct scatterlist *sg, struct dma_chan *chan,
-			      enum dma_transfer_direction dir)
+static int rspi_dma_transfer(struct rspi_data *rspi, struct sg_table *tx,
+			     struct sg_table *rx)
 {
-	dma_unmap_sg(chan->device->dev, sg, 1, dir);
-}
-
-static void rspi_memory_to_8bit(void *buf, const void *data, unsigned len)
-{
-	u16 *dst = buf;
-	const u8 *src = data;
-
-	while (len) {
-		*dst++ = (u16)(*src++);
-		len--;
-	}
-}
-
-static void rspi_memory_from_8bit(void *buf, const void *data, unsigned len)
-{
-	u8 *dst = buf;
-	const u16 *src = data;
-
-	while (len) {
-		*dst++ = (u8)*src++;
-		len--;
-	}
-}
+	struct dma_async_tx_descriptor *desc_tx = NULL, *desc_rx = NULL;
+	u8 irq_mask = 0;
+	unsigned int other_irq = 0;
+	dma_cookie_t cookie;
+	int ret;
 
-static int rspi_send_dma(struct rspi_data *rspi, struct spi_transfer *t)
-{
-	struct scatterlist sg;
-	const void *buf = NULL;
-	struct dma_async_tx_descriptor *desc;
-	unsigned int len;
-	int ret = 0;
-
-	if (rspi->dma_width_16bit) {
-		void *tmp;
-		/*
-		 * If DMAC bus width is 16-bit, the driver allocates a dummy
-		 * buffer. And, the driver converts original data into the
-		 * DMAC data as the following format:
-		 *  original data: 1st byte, 2nd byte ...
-		 *  DMAC data:     1st byte, dummy, 2nd byte, dummy ...
-		 */
-		len = t->len * 2;
-		tmp = kmalloc(len, GFP_KERNEL);
-		if (!tmp)
-			return -ENOMEM;
-		rspi_memory_to_8bit(tmp, t->tx_buf, t->len);
-		buf = tmp;
-	} else {
-		len = t->len;
-		buf = t->tx_buf;
-	}
+	if (tx) {
+		desc_tx = dmaengine_prep_slave_sg(rspi->master->dma_tx,
+					tx->sgl, tx->nents, DMA_TO_DEVICE,
+					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+		if (!desc_tx)
+			return -EIO;
 
-	if (!rspi_dma_map_sg(&sg, buf, len, rspi->chan_tx, DMA_TO_DEVICE)) {
-		ret = -EFAULT;
-		goto end_nomap;
+		irq_mask |= SPCR_SPTIE;
 	}
-	desc = dmaengine_prep_slave_sg(rspi->chan_tx, &sg, 1, DMA_TO_DEVICE,
-				       DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
-	if (!desc) {
-		ret = -EIO;
-		goto end;
+	if (rx) {
+		desc_rx = dmaengine_prep_slave_sg(rspi->master->dma_rx,
+					rx->sgl, rx->nents, DMA_FROM_DEVICE,
+					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+		if (!desc_rx)
+			return -EIO;
+
+		irq_mask |= SPCR_SPRIE;
 	}
 
 	/*
-	 * DMAC needs SPTIE, but if SPTIE is set, this IRQ routine will be
+	 * DMAC needs SPxIE, but if SPxIE is set, the IRQ routine will be
 	 * called. So, this driver disables the IRQ while DMA transfer.
 	 */
-	disable_irq(rspi->tx_irq);
+	if (tx)
+		disable_irq(other_irq = rspi->tx_irq);
+	if (rx && rspi->rx_irq != other_irq)
+		disable_irq(rspi->rx_irq);
 
-	rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) | SPCR_TXMD, RSPI_SPCR);
-	rspi_enable_irq(rspi, SPCR_SPTIE);
+	rspi_enable_irq(rspi, irq_mask);
 	rspi->dma_callbacked = 0;
 
-	desc->callback = rspi_dma_complete;
-	desc->callback_param = rspi;
-	dmaengine_submit(desc);
-	dma_async_issue_pending(rspi->chan_tx);
+	if (rx) {
+		desc_rx->callback = rspi_dma_complete;
+		desc_rx->callback_param = rspi;
+		cookie = dmaengine_submit(desc_rx);
+		if (dma_submit_error(cookie))
+			return cookie;
+		dma_async_issue_pending(rspi->master->dma_rx);
+	}
+	if (tx) {
+		if (rx) {
+			/* No callback */
+			desc_tx->callback = NULL;
+		} else {
+			desc_tx->callback = rspi_dma_complete;
+			desc_tx->callback_param = rspi;
+		}
+		cookie = dmaengine_submit(desc_tx);
+		if (dma_submit_error(cookie))
+			return cookie;
+		dma_async_issue_pending(rspi->master->dma_tx);
+	}
 
 	ret = wait_event_interruptible_timeout(rspi->wait,
 					       rspi->dma_callbacked, HZ);
@@ -542,15 +531,13 @@ static int rspi_send_dma(struct rspi_data *rspi, struct spi_transfer *t)
 		ret = 0;
 	else if (!ret)
 		ret = -ETIMEDOUT;
-	rspi_disable_irq(rspi, SPCR_SPTIE);
 
-	enable_irq(rspi->tx_irq);
+	rspi_disable_irq(rspi, irq_mask);
 
-end:
-	rspi_dma_unmap_sg(&sg, rspi->chan_tx, DMA_TO_DEVICE);
-end_nomap:
-	if (rspi->dma_width_16bit)
-		kfree(buf);
+	if (tx)
+		enable_irq(rspi->tx_irq);
+	if (rx && rspi->rx_irq != other_irq)
+		enable_irq(rspi->rx_irq);
 
 	return ret;
 }
@@ -585,157 +572,37 @@ static void qspi_receive_init(const struct rspi_data *rspi)
 	rspi_write8(rspi, 0, QSPI_SPBFCR);
 }
 
-static int rspi_receive_dma(struct rspi_data *rspi, struct spi_transfer *t)
+static bool __rspi_can_dma(const struct rspi_data *rspi,
+			   const struct spi_transfer *xfer)
 {
-	struct scatterlist sg, sg_dummy;
-	void *dummy = NULL, *rx_buf = NULL;
-	struct dma_async_tx_descriptor *desc, *desc_dummy;
-	unsigned int len;
-	int ret = 0;
-
-	if (rspi->dma_width_16bit) {
-		/*
-		 * If DMAC bus width is 16-bit, the driver allocates a dummy
-		 * buffer. And, finally the driver converts the DMAC data into
-		 * actual data as the following format:
-		 *  DMAC data:   1st byte, dummy, 2nd byte, dummy ...
-		 *  actual data: 1st byte, 2nd byte ...
-		 */
-		len = t->len * 2;
-		rx_buf = kmalloc(len, GFP_KERNEL);
-		if (!rx_buf)
-			return -ENOMEM;
-	 } else {
-		len = t->len;
-		rx_buf = t->rx_buf;
-	}
-
-	/* prepare dummy transfer to generate SPI clocks */
-	dummy = kzalloc(len, GFP_KERNEL);
-	if (!dummy) {
-		ret = -ENOMEM;
-		goto end_nomap;
-	}
-	if (!rspi_dma_map_sg(&sg_dummy, dummy, len, rspi->chan_tx,
-			     DMA_TO_DEVICE)) {
-		ret = -EFAULT;
-		goto end_nomap;
-	}
-	desc_dummy = dmaengine_prep_slave_sg(rspi->chan_tx, &sg_dummy, 1,
-			DMA_TO_DEVICE, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
-	if (!desc_dummy) {
-		ret = -EIO;
-		goto end_dummy_mapped;
-	}
-
-	/* prepare receive transfer */
-	if (!rspi_dma_map_sg(&sg, rx_buf, len, rspi->chan_rx,
-			     DMA_FROM_DEVICE)) {
-		ret = -EFAULT;
-		goto end_dummy_mapped;
-
-	}
-	desc = dmaengine_prep_slave_sg(rspi->chan_rx, &sg, 1, DMA_FROM_DEVICE,
-				       DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
-	if (!desc) {
-		ret = -EIO;
-		goto end;
-	}
-
-	rspi_receive_init(rspi);
-
-	/*
-	 * DMAC needs SPTIE, but if SPTIE is set, this IRQ routine will be
-	 * called. So, this driver disables the IRQ while DMA transfer.
-	 */
-	disable_irq(rspi->tx_irq);
-	if (rspi->rx_irq != rspi->tx_irq)
-		disable_irq(rspi->rx_irq);
-
-	rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) & ~SPCR_TXMD, RSPI_SPCR);
-	rspi_enable_irq(rspi, SPCR_SPTIE | SPCR_SPRIE);
-	rspi->dma_callbacked = 0;
-
-	desc->callback = rspi_dma_complete;
-	desc->callback_param = rspi;
-	dmaengine_submit(desc);
-	dma_async_issue_pending(rspi->chan_rx);
-
-	desc_dummy->callback = NULL;	/* No callback */
-	dmaengine_submit(desc_dummy);
-	dma_async_issue_pending(rspi->chan_tx);
-
-	ret = wait_event_interruptible_timeout(rspi->wait,
-					       rspi->dma_callbacked, HZ);
-	if (ret > 0 && rspi->dma_callbacked)
-		ret = 0;
-	else if (!ret)
-		ret = -ETIMEDOUT;
-	rspi_disable_irq(rspi, SPCR_SPTIE | SPCR_SPRIE);
-
-	enable_irq(rspi->tx_irq);
-	if (rspi->rx_irq != rspi->tx_irq)
-		enable_irq(rspi->rx_irq);
-
-end:
-	rspi_dma_unmap_sg(&sg, rspi->chan_rx, DMA_FROM_DEVICE);
-end_dummy_mapped:
-	rspi_dma_unmap_sg(&sg_dummy, rspi->chan_tx, DMA_TO_DEVICE);
-end_nomap:
-	if (rspi->dma_width_16bit) {
-		if (!ret)
-			rspi_memory_from_8bit(t->rx_buf, rx_buf, t->len);
-		kfree(rx_buf);
-	}
-	kfree(dummy);
-
-	return ret;
+	return xfer->len > rspi->ops->fifo_size;
 }
 
-static int rspi_is_dma(const struct rspi_data *rspi, struct spi_transfer *t)
+static bool rspi_can_dma(struct spi_master *master, struct spi_device *spi,
+			 struct spi_transfer *xfer)
 {
-	if (t->tx_buf && rspi->chan_tx)
-		return 1;
-	/* If the module receives data by DMAC, it also needs TX DMAC */
-	if (t->rx_buf && rspi->chan_tx && rspi->chan_rx)
-		return 1;
+	struct rspi_data *rspi = spi_master_get_devdata(master);
 
-	return 0;
+	return __rspi_can_dma(rspi, xfer);
 }
 
-static int rspi_transfer_out_in(struct rspi_data *rspi,
+static int rspi_common_transfer(struct rspi_data *rspi,
 				struct spi_transfer *xfer)
 {
-	int remain = xfer->len, ret;
-	const u8 *tx_buf = xfer->tx_buf;
-	u8 *rx_buf = xfer->rx_buf;
-	u8 spcr, data;
-
-	rspi_receive_init(rspi);
-
-	spcr = rspi_read8(rspi, RSPI_SPCR);
-	if (rx_buf)
-		spcr &= ~SPCR_TXMD;
-	else
-		spcr |= SPCR_TXMD;
-	rspi_write8(rspi, spcr, RSPI_SPCR);
+	int ret;
 
-	while (remain > 0) {
-		data = tx_buf ? *tx_buf++ : DUMMY_DATA;
-		ret = rspi_data_out(rspi, data);
-		if (ret < 0)
-			return ret;
-		if (rx_buf) {
-			ret = rspi_data_in(rspi);
-			if (ret < 0)
-				return ret;
-			*rx_buf++ = ret;
-		}
-		remain--;
+	if (rspi->master->can_dma && __rspi_can_dma(rspi, xfer)) {
+		/* rx_buf can be NULL on RSPI on SH in TX-only Mode */
+		return rspi_dma_transfer(rspi, &xfer->tx_sg,
+					 xfer->rx_buf ? &xfer->rx_sg : NULL);
 	}
 
+	ret = rspi_pio_transfer(rspi, xfer->tx_buf, xfer->rx_buf, xfer->len);
+	if (ret < 0)
+		return ret;
+
 	/* Wait for the last transmission */
-	rspi_wait_for_interrupt(rspi, SPSR_SPTEF, SPCR_SPTIE);
+	rspi_wait_for_tx_empty(rspi);
 
 	return 0;
 }
@@ -744,46 +611,18 @@ static int rspi_transfer_one(struct spi_master *master, struct spi_device *spi,
 			     struct spi_transfer *xfer)
 {
 	struct rspi_data *rspi = spi_master_get_devdata(master);
-	int ret;
+	u8 spcr;
 
-	if (!rspi_is_dma(rspi, xfer))
-		return rspi_transfer_out_in(rspi, xfer);
-
-	if (xfer->tx_buf) {
-		ret = rspi_send_dma(rspi, xfer);
-		if (ret < 0)
-			return ret;
-	}
-	if (xfer->rx_buf)
-		return rspi_receive_dma(rspi, xfer);
-
-	return 0;
-}
-
-static int rspi_rz_transfer_out_in(struct rspi_data *rspi,
-				   struct spi_transfer *xfer)
-{
-	int remain = xfer->len, ret;
-	const u8 *tx_buf = xfer->tx_buf;
-	u8 *rx_buf = xfer->rx_buf;
-	u8 data;
-
-	rspi_rz_receive_init(rspi);
-
-	while (remain > 0) {
-		data = tx_buf ? *tx_buf++ : DUMMY_DATA;
-		ret = rspi_data_out_in(rspi, data);
-		if (ret < 0)
-			return ret;
-		if (rx_buf)
-			*rx_buf++ = ret;
-		remain--;
+	spcr = rspi_read8(rspi, RSPI_SPCR);
+	if (xfer->rx_buf) {
+		rspi_receive_init(rspi);
+		spcr &= ~SPCR_TXMD;
+	} else {
+		spcr |= SPCR_TXMD;
 	}
+	rspi_write8(rspi, spcr, RSPI_SPCR);
 
-	/* Wait for the last transmission */
-	rspi_wait_for_interrupt(rspi, SPSR_SPTEF, SPCR_SPTIE);
-
-	return 0;
+	return rspi_common_transfer(rspi, xfer);
 }
 
 static int rspi_rz_transfer_one(struct spi_master *master,
@@ -791,68 +630,44 @@ static int rspi_rz_transfer_one(struct spi_master *master,
 				struct spi_transfer *xfer)
 {
 	struct rspi_data *rspi = spi_master_get_devdata(master);
+	int ret;
 
-	return rspi_rz_transfer_out_in(rspi, xfer);
+	rspi_rz_receive_init(rspi);
+
+	return rspi_common_transfer(rspi, xfer);
 }
 
 static int qspi_transfer_out_in(struct rspi_data *rspi,
 				struct spi_transfer *xfer)
 {
-	int remain = xfer->len, ret;
-	const u8 *tx_buf = xfer->tx_buf;
-	u8 *rx_buf = xfer->rx_buf;
-	u8 data;
-
 	qspi_receive_init(rspi);
 
-	while (remain > 0) {
-		data = tx_buf ? *tx_buf++ : DUMMY_DATA;
-		ret = rspi_data_out_in(rspi, data);
-		if (ret < 0)
-			return ret;
-		if (rx_buf)
-			*rx_buf++ = ret;
-		remain--;
-	}
-
-	/* Wait for the last transmission */
-	rspi_wait_for_interrupt(rspi, SPSR_SPTEF, SPCR_SPTIE);
-
-	return 0;
+	return rspi_common_transfer(rspi, xfer);
 }
 
 static int qspi_transfer_out(struct rspi_data *rspi, struct spi_transfer *xfer)
 {
-	const u8 *buf = xfer->tx_buf;
-	unsigned int i;
 	int ret;
 
-	for (i = 0; i < xfer->len; i++) {
-		ret = rspi_data_out(rspi, *buf++);
-		if (ret < 0)
-			return ret;
-	}
+	if (rspi->master->can_dma && __rspi_can_dma(rspi, xfer))
+		return rspi_dma_transfer(rspi, &xfer->tx_sg, NULL);
+
+	ret = rspi_pio_transfer(rspi, xfer->tx_buf, NULL, xfer->len);
+	if (ret < 0)
+		return ret;
 
 	/* Wait for the last transmission */
-	rspi_wait_for_interrupt(rspi, SPSR_SPTEF, SPCR_SPTIE);
+	rspi_wait_for_tx_empty(rspi);
 
 	return 0;
 }
 
 static int qspi_transfer_in(struct rspi_data *rspi, struct spi_transfer *xfer)
 {
-	u8 *buf = xfer->rx_buf;
-	unsigned int i;
-	int ret;
-
-	for (i = 0; i < xfer->len; i++) {
-		ret = rspi_data_in(rspi);
-		if (ret < 0)
-			return ret;
-		*buf++ = ret;
-	}
+	if (rspi->master->can_dma && __rspi_can_dma(rspi, xfer))
+		return rspi_dma_transfer(rspi, NULL, &xfer->rx_sg);
 
-	return 0;
+	return rspi_pio_transfer(rspi, NULL, xfer->rx_buf, xfer->len);
 }
 
 static int qspi_transfer_one(struct spi_master *master, struct spi_device *spi,
@@ -862,10 +677,10 @@ static int qspi_transfer_one(struct spi_master *master, struct spi_device *spi,
 
 	if (spi->mode & SPI_LOOP) {
 		return qspi_transfer_out_in(rspi, xfer);
-	} else if (xfer->tx_buf && xfer->tx_nbits > SPI_NBITS_SINGLE) {
+	} else if (xfer->tx_nbits > SPI_NBITS_SINGLE) {
 		/* Quad or Dual SPI Write */
 		return qspi_transfer_out(rspi, xfer);
-	} else if (xfer->rx_buf && xfer->rx_nbits > SPI_NBITS_SINGLE) {
+	} else if (xfer->rx_nbits > SPI_NBITS_SINGLE) {
 		/* Quad or Dual SPI Read */
 		return qspi_transfer_in(rspi, xfer);
 	} else {
@@ -1046,65 +861,78 @@ static irqreturn_t rspi_irq_tx(int irq, void *_sr)
 	return 0;
 }
 
-static int rspi_request_dma(struct rspi_data *rspi,
-				      struct platform_device *pdev)
+static struct dma_chan *rspi_request_dma_chan(struct device *dev,
+					      enum dma_transfer_direction dir,
+					      unsigned int id,
+					      dma_addr_t port_addr)
 {
-	const struct rspi_plat_data *rspi_pd = dev_get_platdata(&pdev->dev);
-	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	dma_cap_mask_t mask;
+	struct dma_chan *chan;
 	struct dma_slave_config cfg;
 	int ret;
 
-	if (!res || !rspi_pd)
-		return 0;	/* The driver assumes no error. */
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
 
-	rspi->dma_width_16bit = rspi_pd->dma_width_16bit;
-
-	/* If the module receives data by DMAC, it also needs TX DMAC */
-	if (rspi_pd->dma_rx_id && rspi_pd->dma_tx_id) {
-		dma_cap_zero(mask);
-		dma_cap_set(DMA_SLAVE, mask);
-		rspi->chan_rx = dma_request_channel(mask, shdma_chan_filter,
-						    (void *)rspi_pd->dma_rx_id);
-		if (rspi->chan_rx) {
-			cfg.slave_id = rspi_pd->dma_rx_id;
-			cfg.direction = DMA_DEV_TO_MEM;
-			cfg.dst_addr = 0;
-			cfg.src_addr = res->start + RSPI_SPDR;
-			ret = dmaengine_slave_config(rspi->chan_rx, &cfg);
-			if (!ret)
-				dev_info(&pdev->dev, "Use DMA when rx.\n");
-			else
-				return ret;
-		}
+	chan = dma_request_channel(mask, shdma_chan_filter,
+				   (void *)(unsigned long)id);
+	if (!chan) {
+		dev_warn(dev, "dma_request_channel failed\n");
+		return NULL;
 	}
-	if (rspi_pd->dma_tx_id) {
-		dma_cap_zero(mask);
-		dma_cap_set(DMA_SLAVE, mask);
-		rspi->chan_tx = dma_request_channel(mask, shdma_chan_filter,
-						    (void *)rspi_pd->dma_tx_id);
-		if (rspi->chan_tx) {
-			cfg.slave_id = rspi_pd->dma_tx_id;
-			cfg.direction = DMA_MEM_TO_DEV;
-			cfg.dst_addr = res->start + RSPI_SPDR;
-			cfg.src_addr = 0;
-			ret = dmaengine_slave_config(rspi->chan_tx, &cfg);
-			if (!ret)
-				dev_info(&pdev->dev, "Use DMA when tx\n");
-			else
-				return ret;
-		}
+
+	memset(&cfg, 0, sizeof(cfg));
+	cfg.slave_id = id;
+	cfg.direction = dir;
+	if (dir == DMA_MEM_TO_DEV)
+		cfg.dst_addr = port_addr;
+	else
+		cfg.src_addr = port_addr;
+
+	ret = dmaengine_slave_config(chan, &cfg);
+	if (ret) {
+		dev_warn(dev, "dmaengine_slave_config failed %d\n", ret);
+		dma_release_channel(chan);
+		return NULL;
 	}
 
+	return chan;
+}
+
+static int rspi_request_dma(struct device *dev, struct spi_master *master,
+			    const struct resource *res)
+{
+	const struct rspi_plat_data *rspi_pd = dev_get_platdata(dev);
+
+	if (!rspi_pd || !rspi_pd->dma_rx_id || !rspi_pd->dma_tx_id)
+		return 0;	/* The driver assumes no error. */
+
+	master->dma_rx = rspi_request_dma_chan(dev, DMA_DEV_TO_MEM,
+					       rspi_pd->dma_rx_id,
+					       res->start + RSPI_SPDR);
+	if (!master->dma_rx)
+		return -ENODEV;
+
+	master->dma_tx = rspi_request_dma_chan(dev, DMA_MEM_TO_DEV,
+					       rspi_pd->dma_tx_id,
+					       res->start + RSPI_SPDR);
+	if (!master->dma_tx) {
+		dma_release_channel(master->dma_rx);
+		master->dma_rx = NULL;
+		return -ENODEV;
+	}
+
+	master->can_dma = rspi_can_dma;
+	dev_info(dev, "DMA available");
 	return 0;
 }
 
 static void rspi_release_dma(struct rspi_data *rspi)
 {
-	if (rspi->chan_tx)
-		dma_release_channel(rspi->chan_tx);
-	if (rspi->chan_rx)
-		dma_release_channel(rspi->chan_rx);
+	if (rspi->master->dma_tx)
+		dma_release_channel(rspi->master->dma_tx);
+	if (rspi->master->dma_rx)
+		dma_release_channel(rspi->master->dma_rx);
 }
 
 static int rspi_remove(struct platform_device *pdev)
@@ -1118,23 +946,29 @@ static int rspi_remove(struct platform_device *pdev)
 }
 
 static const struct spi_ops rspi_ops = {
-	.set_config_register =		rspi_set_config_register,
-	.transfer_one =			rspi_transfer_one,
-	.mode_bits =			SPI_CPHA | SPI_CPOL | SPI_LOOP,
+	.set_config_register =	rspi_set_config_register,
+	.transfer_one =		rspi_transfer_one,
+	.mode_bits =		SPI_CPHA | SPI_CPOL | SPI_LOOP,
+	.flags =		SPI_MASTER_MUST_TX,
+	.fifo_size =		8,
 };
 
 static const struct spi_ops rspi_rz_ops = {
-	.set_config_register =		rspi_rz_set_config_register,
-	.transfer_one =			rspi_rz_transfer_one,
-	.mode_bits =			SPI_CPHA | SPI_CPOL | SPI_LOOP,
+	.set_config_register =	rspi_rz_set_config_register,
+	.transfer_one =		rspi_rz_transfer_one,
+	.mode_bits =		SPI_CPHA | SPI_CPOL | SPI_LOOP,
+	.flags =		SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX,
+	.fifo_size =		8,	/* 8 for TX, 32 for RX */
 };
 
 static const struct spi_ops qspi_ops = {
-	.set_config_register =		qspi_set_config_register,
-	.transfer_one =			qspi_transfer_one,
-	.mode_bits =			SPI_CPHA | SPI_CPOL | SPI_LOOP |
-					SPI_TX_DUAL | SPI_TX_QUAD |
-					SPI_RX_DUAL | SPI_RX_QUAD,
+	.set_config_register =	qspi_set_config_register,
+	.transfer_one =		qspi_transfer_one,
+	.mode_bits =		SPI_CPHA | SPI_CPOL | SPI_LOOP |
+				SPI_TX_DUAL | SPI_TX_QUAD |
+				SPI_RX_DUAL | SPI_RX_QUAD,
+	.flags =		SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX,
+	.fifo_size =		32,
 };
 
 #ifdef CONFIG_OF
@@ -1254,6 +1088,7 @@ static int rspi_probe(struct platform_device *pdev)
 	master->prepare_message = rspi_prepare_message;
 	master->unprepare_message = rspi_unprepare_message;
 	master->mode_bits = ops->mode_bits;
+	master->flags = ops->flags;
 	master->dev.of_node = pdev->dev.of_node;
 
 	ret = platform_get_irq_byname(pdev, "rx");
@@ -1291,11 +1126,9 @@ static int rspi_probe(struct platform_device *pdev)
 		goto error2;
 	}
 
-	ret = rspi_request_dma(rspi, pdev);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "rspi_request_dma failed.\n");
-		goto error3;
-	}
+	ret = rspi_request_dma(&pdev->dev, master, res);
+	if (ret < 0)
+		dev_warn(&pdev->dev, "DMA not available, using PIO\n");
 
 	ret = devm_spi_register_master(&pdev->dev, master);
 	if (ret < 0) {