[PATCH v2 0/4] Fixes for Vybrid SPI DMA implementation

[PATCH v2 0/4] Fixes for Vybrid SPI DMA implementation

[Sanchayan Maity]

Hello,

The following set of patches have fixes for Vybrid SPI DMA
implementation along with some minor clean ups requested
at time when v3 version of SPI DMA support patch was accepted.

This series of patches is based on top of branch topic/fsl-dspi.
http://git.kernel.org/cgit/linux/kernel/git/broonie/spi.git/log/?h=topic/fsl-dspi

The patches have been tested on a Toradex Colibri Vybrid VF61 module
and now incoporate feedback from Stefan on version 1 of patchset.

Changes since v1:
1. Place the continuous selection format patch second in order and remove
code duplication
2. Improve the use of curr_xfer_len and instead of converting from bytes
to DMA transfers in every use, do it at a single place. Accordingly change
it's use at other places
3. Code cleanup patch has less to clean with change above 

v1:
http://www.mail-archive.com/linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org/msg1274632.html

Thanks & Regards,
Sanchayan.

Sanchayan Maity (4):
  spi: spi-fsl-dspi: Fix SPI transfer issue when using multiple SPI_IOC_MESSAGE
  spi: spi-fsl-dspi: Fix continuous selection format
  spi: spi-fsl-dspi: Fix incorrect DMA setup
  spi: spi-fsl-dspi: Minor code cleanup and error path fixes

 drivers/spi/spi-fsl-dspi.c | 71 ++++++++++++++++++++++++++++------------------
 1 file changed, 44 insertions(+), 27 deletions(-)

-- 
2.10.2

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[PATCH v2 1/4] spi: spi-fsl-dspi: Fix SPI transfer issue when using multiple SPI_IOC_MESSAGE

[Sanchayan Maity]

Current DMA implementation had a bug where the DMA transfer would
exit the loop in dspi_transfer_one_message after the completion of
a single transfer. This results in a multi message transfer submitted
with SPI_IOC_MESSAGE to terminate incorrectly without an error.

Signed-off-by: Sanchayan Maity <maitysanchayan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Reviewed-by: Stefan Agner <stefan-XLVq0VzYD2Y@public.gmane.org>
---
 drivers/spi/spi-fsl-dspi.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index bc64700..b1ee1f5 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -714,7 +714,7 @@ static int dspi_transfer_one_message(struct spi_master *master,
 				SPI_RSER_TFFFE | SPI_RSER_TFFFD |
 				SPI_RSER_RFDFE | SPI_RSER_RFDFD);
 			status = dspi_dma_xfer(dspi);
-			goto out;
+			break;
 		default:
 			dev_err(&dspi->pdev->dev, "unsupported trans_mode %u\n",
 				trans_mode);
@@ -722,9 +722,13 @@ static int dspi_transfer_one_message(struct spi_master *master,
 			goto out;
 		}
 
-		if (wait_event_interruptible(dspi->waitq, dspi->waitflags))
-			dev_err(&dspi->pdev->dev, "wait transfer complete fail!\n");
-		dspi->waitflags = 0;
+		if (trans_mode != DSPI_DMA_MODE) {
+			if (wait_event_interruptible(dspi->waitq,
+						dspi->waitflags))
+				dev_err(&dspi->pdev->dev,
+					"wait transfer complete fail!\n");
+			dspi->waitflags = 0;
+		}
 
 		if (transfer->delay_usecs)
 			udelay(transfer->delay_usecs);
-- 
2.10.2

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Re: [PATCH v2 1/4] spi: spi-fsl-dspi: Fix SPI transfer issue when using multiple SPI_IOC_MESSAGE

[Mark Brown]

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On Mon, Nov 21, 2016 at 11:24:01AM +0530, Sanchayan Maity wrote:
> Current DMA implementation had a bug where the DMA transfer would
> exit the loop in dspi_transfer_one_message after the completion of
> a single transfer. This results in a multi message transfer submitted
> with SPI_IOC_MESSAGE to terminate incorrectly without an error.

Please don't resend already applied patches.  If there are any changes
needed please send incremental changes on top of what's already applied.

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Re: [PATCH v2 1/4] spi: spi-fsl-dspi: Fix SPI transfer issue when using multiple SPI_IOC_MESSAGE

[maitysanchayan-Re5JQEeQqe8AvxtiuMwx3w]

Hello Mark,

On 16-11-21 19:18:47, Mark Brown wrote:
> On Mon, Nov 21, 2016 at 11:24:01AM +0530, Sanchayan Maity wrote:
> > Current DMA implementation had a bug where the DMA transfer would
> > exit the loop in dspi_transfer_one_message after the completion of
> > a single transfer. This results in a multi message transfer submitted
> > with SPI_IOC_MESSAGE to terminate incorrectly without an error.
> 
> Please don't resend already applied patches.  If there are any changes
> needed please send incremental changes on top of what's already applied.

This is not a resend of an applied patch. The whole series applies on
top of your topic/fsl-dspi branch and has fixes for the SPI DMA as
incremental changes

- Sanchaya.
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Re: [PATCH v2 1/4] spi: spi-fsl-dspi: Fix SPI transfer issue when using multiple SPI_IOC_MESSAGE

[maitysanchayan]

Hello Mark,

On 16-11-22 00:44:30, maitysanchayan@gmail.com wrote:
> Hello Mark,
> 
> On 16-11-21 19:18:47, Mark Brown wrote:
> > On Mon, Nov 21, 2016 at 11:24:01AM +0530, Sanchayan Maity wrote:
> > > Current DMA implementation had a bug where the DMA transfer would
> > > exit the loop in dspi_transfer_one_message after the completion of
> > > a single transfer. This results in a multi message transfer submitted
> > > with SPI_IOC_MESSAGE to terminate incorrectly without an error.
> > 
> > Please don't resend already applied patches.  If there are any changes
> > needed please send incremental changes on top of what's already applied.
> 
> This is not a resend of an applied patch. The whole series applies on
> top of your topic/fsl-dspi branch and has fixes for the SPI DMA as
> incremental changes
> 
Sorry. I take that back. I now see you applied the patch and I got the applied
mail after I replied.

- Sanchayan.

Re: [PATCH v2 1/4] spi: spi-fsl-dspi: Fix SPI transfer issue when using multiple SPI_IOC_MESSAGE

[Mark Brown]

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On Tue, Nov 22, 2016 at 12:48:50AM +0530, maitysanchayan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org wrote:
> On 16-11-22 00:44:30, maitysanchayan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org wrote:

> > This is not a resend of an applied patch. The whole series applies on
> > top of your topic/fsl-dspi branch and has fixes for the SPI DMA as
> > incremental changes

> Sorry. I take that back. I now see you applied the patch and I got the applied
> mail after I replied.

Ah, I did apply it on Friday but somehow it didn't get pushed until
yesterday.  Sorry for the confusion.

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[PATCH v2 2/4] spi: spi-fsl-dspi: Fix continuous selection format

[Sanchayan Maity]

Current DMA implementation was not handling the continuous selection
format viz. SPI chip select would be deasserted even between sequential
serial transfers. Use the cs_change variable and correctly set or
reset the CONT bit accordingly for case where peripherals require
the chip select to be asserted between sequential transfers.

Signed-off-by: Sanchayan Maity <maitysanchayan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/spi/spi-fsl-dspi.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index b1ee1f5..41422cd 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -261,6 +261,8 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
 	dspi->dma->tx_dma_buf[i] = SPI_PUSHR_TXDATA(val) |
 					SPI_PUSHR_PCS(dspi->cs) |
 					SPI_PUSHR_CTAS(0);
+	if (!dspi->cs_change)
+		dspi->dma->tx_dma_buf[i] |= SPI_PUSHR_CONT;
 	dspi->tx += tx_word + 1;
 
 	dma->tx_desc = dmaengine_prep_slave_single(dma->chan_tx,
-- 
2.10.2

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Re: [PATCH v2 2/4] spi: spi-fsl-dspi: Fix continuous selection format

[Stefan Agner]

On 2016-11-20 21:54, Sanchayan Maity wrote:
> Current DMA implementation was not handling the continuous selection
> format viz. SPI chip select would be deasserted even between sequential
> serial transfers. Use the cs_change variable and correctly set or
> reset the CONT bit accordingly for case where peripherals require
> the chip select to be asserted between sequential transfers.
> 
> Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
> ---
>  drivers/spi/spi-fsl-dspi.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
> index b1ee1f5..41422cd 100644
> --- a/drivers/spi/spi-fsl-dspi.c
> +++ b/drivers/spi/spi-fsl-dspi.c
> @@ -261,6 +261,8 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
>  	dspi->dma->tx_dma_buf[i] = SPI_PUSHR_TXDATA(val) |
>  					SPI_PUSHR_PCS(dspi->cs) |
>  					SPI_PUSHR_CTAS(0);
> +	if (!dspi->cs_change)
> +		dspi->dma->tx_dma_buf[i] |= SPI_PUSHR_CONT;
>  	dspi->tx += tx_word + 1;
>  
>  	dma->tx_desc = dmaengine_prep_slave_single(dma->chan_tx,

Other transfer mode use:

if ((dspi->cs_change) && (!dspi->len))                                  
                                                           
        dspi_pushr &= ~SPI_PUSHR_CONT;

which indicates that they only clear SPI_PUSHR_CONT at the very end of a
transfer... The DMA code currently deselects after every DMA transfer if
dspi->cs_change is set.

Maybe we should use the helper dspi_data_to_pushr to fill the DMA buffer
and _clear_ SPI_PUSHR_CONT if necessary like the other transfer modes
do... Then we can use the for loop to fill the complete buffer and get
rid of some code dupplication.

I see that dspi_data_to_pushr does move len too, which we did not in the
DMA case. dspi->len gets incremented only on successful DMA transfer in
dspi_dma_xfer. However, I wonder if that is not even a bug: We increment
dspi->tx always, but len only on success. This makes len go off sync
with regards to the tx pointer which does not help anybody. So lets get
rid of the update code in dspi_dma_xfer

--
Stefan

Re: [PATCH v2 2/4] spi: spi-fsl-dspi: Fix continuous selection format

[maitysanchayan-Re5JQEeQqe8AvxtiuMwx3w]

On 16-11-21 15:15:41, Stefan Agner wrote:
> On 2016-11-20 21:54, Sanchayan Maity wrote:
> > Current DMA implementation was not handling the continuous selection
> > format viz. SPI chip select would be deasserted even between sequential
> > serial transfers. Use the cs_change variable and correctly set or
> > reset the CONT bit accordingly for case where peripherals require
> > the chip select to be asserted between sequential transfers.
> > 
> > Signed-off-by: Sanchayan Maity <maitysanchayan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> > ---
> >  drivers/spi/spi-fsl-dspi.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
> > index b1ee1f5..41422cd 100644
> > --- a/drivers/spi/spi-fsl-dspi.c
> > +++ b/drivers/spi/spi-fsl-dspi.c
> > @@ -261,6 +261,8 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
> >  	dspi->dma->tx_dma_buf[i] = SPI_PUSHR_TXDATA(val) |
> >  					SPI_PUSHR_PCS(dspi->cs) |
> >  					SPI_PUSHR_CTAS(0);
> > +	if (!dspi->cs_change)
> > +		dspi->dma->tx_dma_buf[i] |= SPI_PUSHR_CONT;
> >  	dspi->tx += tx_word + 1;
> >  
> >  	dma->tx_desc = dmaengine_prep_slave_single(dma->chan_tx,
> 
> Other transfer mode use:
> 
> if ((dspi->cs_change) && (!dspi->len))                                  
>                                                            
>         dspi_pushr &= ~SPI_PUSHR_CONT;
> 
> which indicates that they only clear SPI_PUSHR_CONT at the very end of a
> transfer... The DMA code currently deselects after every DMA transfer if
> dspi->cs_change is set.
> 
> Maybe we should use the helper dspi_data_to_pushr to fill the DMA buffer
> and _clear_ SPI_PUSHR_CONT if necessary like the other transfer modes
> do... Then we can use the for loop to fill the complete buffer and get
> rid of some code dupplication.
> 
> I see that dspi_data_to_pushr does move len too, which we did not in the
> DMA case. dspi->len gets incremented only on successful DMA transfer in
> dspi_dma_xfer. However, I wonder if that is not even a bug: We increment
> dspi->tx always, but len only on success. This makes len go off sync
> with regards to the tx pointer which does not help anybody. So lets get
> rid of the update code in dspi_dma_xfer
> 

Thanks for the feedback. Using dspi_data_to_pushr really cleans up that
tx path very nicely. Why didn't I see it. Will send a follow up patch
soon after testing again.

- Sanchayan.
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[PATCH v2 3/4] spi: spi-fsl-dspi: Fix incorrect DMA setup

[Sanchayan Maity]

Currently dmaengine_prep_slave_single was being called with length
set to the complete DMA buffer size. This resulted in unwanted bytes
being transferred to the SPI register leading to clock and MOSI lines
having unwanted data even after chip select got deasserted and the
required bytes having been transferred.

While at it also clean up the use of curr_xfer_len which is central
to the DMA setup, from bytes to DMA transfers for every use.

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
---
 drivers/spi/spi-fsl-dspi.c | 35 ++++++++++++++++++-----------------
 1 file changed, 18 insertions(+), 17 deletions(-)

diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index 41422cd..08882f7 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -151,6 +151,7 @@ static const struct fsl_dspi_devtype_data ls2085a_data = {
 };
 
 struct fsl_dspi_dma {
+	/* Length of transfer in words of DSPI_FIFO_SIZE */
 	u32 curr_xfer_len;
 
 	u32 *tx_dma_buf;
@@ -217,15 +218,13 @@ static void dspi_rx_dma_callback(void *arg)
 	struct fsl_dspi *dspi = arg;
 	struct fsl_dspi_dma *dma = dspi->dma;
 	int rx_word;
-	int i, len;
+	int i;
 	u16 d;
 
 	rx_word = is_double_byte_mode(dspi);
 
-	len = rx_word ? (dma->curr_xfer_len / 2) : dma->curr_xfer_len;
-
 	if (!(dspi->dataflags & TRAN_STATE_RX_VOID)) {
-		for (i = 0; i < len; i++) {
+		for (i = 0; i < dma->curr_xfer_len; i++) {
 			d = dspi->dma->rx_dma_buf[i];
 			rx_word ? (*(u16 *)dspi->rx = d) :
 						(*(u8 *)dspi->rx = d);
@@ -242,14 +241,12 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
 	struct device *dev = &dspi->pdev->dev;
 	int time_left;
 	int tx_word;
-	int i, len;
+	int i;
 	u16 val;
 
 	tx_word = is_double_byte_mode(dspi);
 
-	len = tx_word ? (dma->curr_xfer_len / 2) : dma->curr_xfer_len;
-
-	for (i = 0; i < len - 1; i++) {
+	for (i = 0; i < dma->curr_xfer_len - 1; i++) {
 		val = tx_word ? *(u16 *) dspi->tx : *(u8 *) dspi->tx;
 		dspi->dma->tx_dma_buf[i] =
 			SPI_PUSHR_TXDATA(val) | SPI_PUSHR_PCS(dspi->cs) |
@@ -267,7 +264,9 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
 
 	dma->tx_desc = dmaengine_prep_slave_single(dma->chan_tx,
 					dma->tx_dma_phys,
-					DSPI_DMA_BUFSIZE, DMA_MEM_TO_DEV,
+					dma->curr_xfer_len *
+					DMA_SLAVE_BUSWIDTH_4_BYTES,
+					DMA_MEM_TO_DEV,
 					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 	if (!dma->tx_desc) {
 		dev_err(dev, "Not able to get desc for DMA xfer\n");
@@ -283,7 +282,9 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
 
 	dma->rx_desc = dmaengine_prep_slave_single(dma->chan_rx,
 					dma->rx_dma_phys,
-					DSPI_DMA_BUFSIZE, DMA_DEV_TO_MEM,
+					dma->curr_xfer_len *
+					DMA_SLAVE_BUSWIDTH_4_BYTES,
+					DMA_DEV_TO_MEM,
 					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 	if (!dma->rx_desc) {
 		dev_err(dev, "Not able to get desc for DMA xfer\n");
@@ -330,17 +331,17 @@ static int dspi_dma_xfer(struct fsl_dspi *dspi)
 	struct device *dev = &dspi->pdev->dev;
 	int curr_remaining_bytes;
 	int bytes_per_buffer;
-	int tx_word;
+	int word = 1;
 	int ret = 0;
 
-	tx_word = is_double_byte_mode(dspi);
+	if (is_double_byte_mode(dspi))
+		word = 2;
 	curr_remaining_bytes = dspi->len;
+	bytes_per_buffer = DSPI_DMA_BUFSIZE / DSPI_FIFO_SIZE;
 	while (curr_remaining_bytes) {
 		/* Check if current transfer fits the DMA buffer */
-		dma->curr_xfer_len = curr_remaining_bytes;
-		bytes_per_buffer = DSPI_DMA_BUFSIZE /
-				(DSPI_FIFO_SIZE / (tx_word ? 2 : 1));
-		if (curr_remaining_bytes > bytes_per_buffer)
+		dma->curr_xfer_len = curr_remaining_bytes / word;
+		if (dma->curr_xfer_len > bytes_per_buffer)
 			dma->curr_xfer_len = bytes_per_buffer;
 
 		ret = dspi_next_xfer_dma_submit(dspi);
@@ -349,7 +350,7 @@ static int dspi_dma_xfer(struct fsl_dspi *dspi)
 			goto exit;
 
 		} else {
-			curr_remaining_bytes -= dma->curr_xfer_len;
+			curr_remaining_bytes -= dma->curr_xfer_len * word;
 			if (curr_remaining_bytes < 0)
 				curr_remaining_bytes = 0;
 			dspi->len = curr_remaining_bytes;
-- 
2.10.2

Re: [PATCH v2 3/4] spi: spi-fsl-dspi: Fix incorrect DMA setup

[Stefan Agner]

On 2016-11-20 21:54, Sanchayan Maity wrote:
> Currently dmaengine_prep_slave_single was being called with length
> set to the complete DMA buffer size. This resulted in unwanted bytes
> being transferred to the SPI register leading to clock and MOSI lines
> having unwanted data even after chip select got deasserted and the
> required bytes having been transferred.
> 
> While at it also clean up the use of curr_xfer_len which is central
> to the DMA setup, from bytes to DMA transfers for every use.
> 
> Signed-off-by: Sanchayan Maity <maitysanchayan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Looks good to me:

Reviewed-by: Stefan Agner <stefan-XLVq0VzYD2Y@public.gmane.org>

> ---
>  drivers/spi/spi-fsl-dspi.c | 35 ++++++++++++++++++-----------------
>  1 file changed, 18 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
> index 41422cd..08882f7 100644
> --- a/drivers/spi/spi-fsl-dspi.c
> +++ b/drivers/spi/spi-fsl-dspi.c
> @@ -151,6 +151,7 @@ static const struct fsl_dspi_devtype_data ls2085a_data = {
>  };
>  
>  struct fsl_dspi_dma {
> +	/* Length of transfer in words of DSPI_FIFO_SIZE */
>  	u32 curr_xfer_len;
>  
>  	u32 *tx_dma_buf;
> @@ -217,15 +218,13 @@ static void dspi_rx_dma_callback(void *arg)
>  	struct fsl_dspi *dspi = arg;
>  	struct fsl_dspi_dma *dma = dspi->dma;
>  	int rx_word;
> -	int i, len;
> +	int i;
>  	u16 d;
>  
>  	rx_word = is_double_byte_mode(dspi);
>  
> -	len = rx_word ? (dma->curr_xfer_len / 2) : dma->curr_xfer_len;
> -
>  	if (!(dspi->dataflags & TRAN_STATE_RX_VOID)) {
> -		for (i = 0; i < len; i++) {
> +		for (i = 0; i < dma->curr_xfer_len; i++) {
>  			d = dspi->dma->rx_dma_buf[i];
>  			rx_word ? (*(u16 *)dspi->rx = d) :
>  						(*(u8 *)dspi->rx = d);
> @@ -242,14 +241,12 @@ static int dspi_next_xfer_dma_submit(struct
> fsl_dspi *dspi)
>  	struct device *dev = &dspi->pdev->dev;
>  	int time_left;
>  	int tx_word;
> -	int i, len;
> +	int i;
>  	u16 val;
>  
>  	tx_word = is_double_byte_mode(dspi);
>  
> -	len = tx_word ? (dma->curr_xfer_len / 2) : dma->curr_xfer_len;
> -
> -	for (i = 0; i < len - 1; i++) {
> +	for (i = 0; i < dma->curr_xfer_len - 1; i++) {
>  		val = tx_word ? *(u16 *) dspi->tx : *(u8 *) dspi->tx;
>  		dspi->dma->tx_dma_buf[i] =
>  			SPI_PUSHR_TXDATA(val) | SPI_PUSHR_PCS(dspi->cs) |
> @@ -267,7 +264,9 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
>  
>  	dma->tx_desc = dmaengine_prep_slave_single(dma->chan_tx,
>  					dma->tx_dma_phys,
> -					DSPI_DMA_BUFSIZE, DMA_MEM_TO_DEV,
> +					dma->curr_xfer_len *
> +					DMA_SLAVE_BUSWIDTH_4_BYTES,
> +					DMA_MEM_TO_DEV,
>  					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
>  	if (!dma->tx_desc) {
>  		dev_err(dev, "Not able to get desc for DMA xfer\n");
> @@ -283,7 +282,9 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
>  
>  	dma->rx_desc = dmaengine_prep_slave_single(dma->chan_rx,
>  					dma->rx_dma_phys,
> -					DSPI_DMA_BUFSIZE, DMA_DEV_TO_MEM,
> +					dma->curr_xfer_len *
> +					DMA_SLAVE_BUSWIDTH_4_BYTES,
> +					DMA_DEV_TO_MEM,
>  					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
>  	if (!dma->rx_desc) {
>  		dev_err(dev, "Not able to get desc for DMA xfer\n");
> @@ -330,17 +331,17 @@ static int dspi_dma_xfer(struct fsl_dspi *dspi)
>  	struct device *dev = &dspi->pdev->dev;
>  	int curr_remaining_bytes;
>  	int bytes_per_buffer;
> -	int tx_word;
> +	int word = 1;
>  	int ret = 0;
>  
> -	tx_word = is_double_byte_mode(dspi);
> +	if (is_double_byte_mode(dspi))
> +		word = 2;
>  	curr_remaining_bytes = dspi->len;
> +	bytes_per_buffer = DSPI_DMA_BUFSIZE / DSPI_FIFO_SIZE;
>  	while (curr_remaining_bytes) {
>  		/* Check if current transfer fits the DMA buffer */
> -		dma->curr_xfer_len = curr_remaining_bytes;
> -		bytes_per_buffer = DSPI_DMA_BUFSIZE /
> -				(DSPI_FIFO_SIZE / (tx_word ? 2 : 1));
> -		if (curr_remaining_bytes > bytes_per_buffer)
> +		dma->curr_xfer_len = curr_remaining_bytes / word;
> +		if (dma->curr_xfer_len > bytes_per_buffer)
>  			dma->curr_xfer_len = bytes_per_buffer;
>  
>  		ret = dspi_next_xfer_dma_submit(dspi);
> @@ -349,7 +350,7 @@ static int dspi_dma_xfer(struct fsl_dspi *dspi)
>  			goto exit;
>  
>  		} else {
> -			curr_remaining_bytes -= dma->curr_xfer_len;
> +			curr_remaining_bytes -= dma->curr_xfer_len * word;
>  			if (curr_remaining_bytes < 0)
>  				curr_remaining_bytes = 0;
>  			dspi->len = curr_remaining_bytes;
--
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Applied "spi: spi-fsl-dspi: Fix incorrect DMA setup" to the spi tree

[Mark Brown]

The patch

   spi: spi-fsl-dspi: Fix incorrect DMA setup

has been applied to the spi tree at

   git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 1eaccf210c59e04eb6e9b5469a60d6609c95ac61 Mon Sep 17 00:00:00 2001
From: Sanchayan Maity <maitysanchayan@gmail.com>
Date: Tue, 22 Nov 2016 12:31:30 +0530
Subject: [PATCH] spi: spi-fsl-dspi: Fix incorrect DMA setup

Currently dmaengine_prep_slave_single was being called with length
set to the complete DMA buffer size. This resulted in unwanted bytes
being transferred to the SPI register leading to clock and MOSI lines
having unwanted data even after chip select got deasserted and the
required bytes having been transferred.

While at it also clean up the use of curr_xfer_len which is central
to the DMA setup, from bytes to DMA transfers for every use.

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-fsl-dspi.c | 35 ++++++++++++++++++-----------------
 1 file changed, 18 insertions(+), 17 deletions(-)

diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index 22f7ce1279bd..cb41c327bd77 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -151,6 +151,7 @@ static const struct fsl_dspi_devtype_data ls2085a_data = {
 };
 
 struct fsl_dspi_dma {
+	/* Length of transfer in words of DSPI_FIFO_SIZE */
 	u32 curr_xfer_len;
 
 	u32 *tx_dma_buf;
@@ -217,15 +218,13 @@ static void dspi_rx_dma_callback(void *arg)
 	struct fsl_dspi *dspi = arg;
 	struct fsl_dspi_dma *dma = dspi->dma;
 	int rx_word;
-	int i, len;
+	int i;
 	u16 d;
 
 	rx_word = is_double_byte_mode(dspi);
 
-	len = rx_word ? (dma->curr_xfer_len / 2) : dma->curr_xfer_len;
-
 	if (!(dspi->dataflags & TRAN_STATE_RX_VOID)) {
-		for (i = 0; i < len; i++) {
+		for (i = 0; i < dma->curr_xfer_len; i++) {
 			d = dspi->dma->rx_dma_buf[i];
 			rx_word ? (*(u16 *)dspi->rx = d) :
 						(*(u8 *)dspi->rx = d);
@@ -242,14 +241,12 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
 	struct device *dev = &dspi->pdev->dev;
 	int time_left;
 	int tx_word;
-	int i, len;
+	int i;
 	u16 val;
 
 	tx_word = is_double_byte_mode(dspi);
 
-	len = tx_word ? (dma->curr_xfer_len / 2) : dma->curr_xfer_len;
-
-	for (i = 0; i < len - 1; i++) {
+	for (i = 0; i < dma->curr_xfer_len - 1; i++) {
 		val = tx_word ? *(u16 *) dspi->tx : *(u8 *) dspi->tx;
 		dspi->dma->tx_dma_buf[i] =
 			SPI_PUSHR_TXDATA(val) | SPI_PUSHR_PCS(dspi->cs) |
@@ -265,7 +262,9 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
 
 	dma->tx_desc = dmaengine_prep_slave_single(dma->chan_tx,
 					dma->tx_dma_phys,
-					DSPI_DMA_BUFSIZE, DMA_MEM_TO_DEV,
+					dma->curr_xfer_len *
+					DMA_SLAVE_BUSWIDTH_4_BYTES,
+					DMA_MEM_TO_DEV,
 					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 	if (!dma->tx_desc) {
 		dev_err(dev, "Not able to get desc for DMA xfer\n");
@@ -281,7 +280,9 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
 
 	dma->rx_desc = dmaengine_prep_slave_single(dma->chan_rx,
 					dma->rx_dma_phys,
-					DSPI_DMA_BUFSIZE, DMA_DEV_TO_MEM,
+					dma->curr_xfer_len *
+					DMA_SLAVE_BUSWIDTH_4_BYTES,
+					DMA_DEV_TO_MEM,
 					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 	if (!dma->rx_desc) {
 		dev_err(dev, "Not able to get desc for DMA xfer\n");
@@ -328,17 +329,17 @@ static int dspi_dma_xfer(struct fsl_dspi *dspi)
 	struct device *dev = &dspi->pdev->dev;
 	int curr_remaining_bytes;
 	int bytes_per_buffer;
-	int tx_word;
+	int word = 1;
 	int ret = 0;
 
-	tx_word = is_double_byte_mode(dspi);
+	if (is_double_byte_mode(dspi))
+		word = 2;
 	curr_remaining_bytes = dspi->len;
+	bytes_per_buffer = DSPI_DMA_BUFSIZE / DSPI_FIFO_SIZE;
 	while (curr_remaining_bytes) {
 		/* Check if current transfer fits the DMA buffer */
-		dma->curr_xfer_len = curr_remaining_bytes;
-		bytes_per_buffer = DSPI_DMA_BUFSIZE /
-				(DSPI_FIFO_SIZE / (tx_word ? 2 : 1));
-		if (curr_remaining_bytes > bytes_per_buffer)
+		dma->curr_xfer_len = curr_remaining_bytes / word;
+		if (dma->curr_xfer_len > bytes_per_buffer)
 			dma->curr_xfer_len = bytes_per_buffer;
 
 		ret = dspi_next_xfer_dma_submit(dspi);
@@ -347,7 +348,7 @@ static int dspi_dma_xfer(struct fsl_dspi *dspi)
 			goto exit;
 
 		} else {
-			curr_remaining_bytes -= dma->curr_xfer_len;
+			curr_remaining_bytes -= dma->curr_xfer_len * word;
 			if (curr_remaining_bytes < 0)
 				curr_remaining_bytes = 0;
 			dspi->len = curr_remaining_bytes;
-- 
2.10.2

[PATCH v2 4/4] spi: spi-fsl-dspi: Minor code cleanup and error path fixes

[Sanchayan Maity]

Code cleanup for improving code readability and error path fixes
and cleanup removing use of devm_kfree.

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
---
 drivers/spi/spi-fsl-dspi.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index 08882f7..2987a16 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -226,8 +226,10 @@ static void dspi_rx_dma_callback(void *arg)
 	if (!(dspi->dataflags & TRAN_STATE_RX_VOID)) {
 		for (i = 0; i < dma->curr_xfer_len; i++) {
 			d = dspi->dma->rx_dma_buf[i];
-			rx_word ? (*(u16 *)dspi->rx = d) :
-						(*(u8 *)dspi->rx = d);
+			if (rx_word)
+				*(u16 *)dspi->rx = d;
+			else
+				*(u8 *)dspi->rx = d;
 			dspi->rx += rx_word + 1;
 		}
 	}
@@ -247,14 +249,20 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
 	tx_word = is_double_byte_mode(dspi);
 
 	for (i = 0; i < dma->curr_xfer_len - 1; i++) {
-		val = tx_word ? *(u16 *) dspi->tx : *(u8 *) dspi->tx;
+		if (tx_word)
+			val = *(u16 *) dspi->tx;
+		else
+			val = *(u8 *) dspi->tx;
 		dspi->dma->tx_dma_buf[i] =
 			SPI_PUSHR_TXDATA(val) | SPI_PUSHR_PCS(dspi->cs) |
 			SPI_PUSHR_CTAS(0) | SPI_PUSHR_CONT;
 		dspi->tx += tx_word + 1;
 	}
 
-	val = tx_word ? *(u16 *) dspi->tx : *(u8 *) dspi->tx;
+	if (tx_word)
+		val = *(u16 *) dspi->tx;
+	else
+		val = *(u8 *) dspi->tx;
 	dspi->dma->tx_dma_buf[i] = SPI_PUSHR_TXDATA(val) |
 					SPI_PUSHR_PCS(dspi->cs) |
 					SPI_PUSHR_CTAS(0);
@@ -430,9 +438,11 @@ static int dspi_request_dma(struct fsl_dspi *dspi, phys_addr_t phy_addr)
 	return 0;
 
 err_slave_config:
-	devm_kfree(dev, dma->rx_dma_buf);
+	dma_free_coherent(dev, DSPI_DMA_BUFSIZE,
+			dma->rx_dma_buf, dma->rx_dma_phys);
 err_rx_dma_buf:
-	devm_kfree(dev, dma->tx_dma_buf);
+	dma_free_coherent(dev, DSPI_DMA_BUFSIZE,
+			dma->tx_dma_buf, dma->tx_dma_phys);
 err_tx_dma_buf:
 	dma_release_channel(dma->chan_tx);
 err_tx_channel:
-- 
2.10.2

Re: [PATCH v2 4/4] spi: spi-fsl-dspi: Minor code cleanup and error path fixes

[Stefan Agner]

On 2016-11-20 21:54, Sanchayan Maity wrote:
> Code cleanup for improving code readability and error path fixes
> and cleanup removing use of devm_kfree.

Two things in one, not very nice. Especially the dma_free_coherent is
really a bug and the other is a cleanup. Can you make a separate patch
for the bug?

As for the cleanup, I don't like the one line conditions too, but I
don't think it is worth a patch. At least the TX path should be solved
with my suggestion in patch 2.

--
Stefan

> 
> Signed-off-by: Sanchayan Maity <maitysanchayan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
>  drivers/spi/spi-fsl-dspi.c | 22 ++++++++++++++++------
>  1 file changed, 16 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
> index 08882f7..2987a16 100644
> --- a/drivers/spi/spi-fsl-dspi.c
> +++ b/drivers/spi/spi-fsl-dspi.c
> @@ -226,8 +226,10 @@ static void dspi_rx_dma_callback(void *arg)
>  	if (!(dspi->dataflags & TRAN_STATE_RX_VOID)) {
>  		for (i = 0; i < dma->curr_xfer_len; i++) {
>  			d = dspi->dma->rx_dma_buf[i];
> -			rx_word ? (*(u16 *)dspi->rx = d) :
> -						(*(u8 *)dspi->rx = d);
> +			if (rx_word)
> +				*(u16 *)dspi->rx = d;
> +			else
> +				*(u8 *)dspi->rx = d;
>  			dspi->rx += rx_word + 1;
>  		}
>  	}
> @@ -247,14 +249,20 @@ static int dspi_next_xfer_dma_submit(struct
> fsl_dspi *dspi)
>  	tx_word = is_double_byte_mode(dspi);
>  
>  	for (i = 0; i < dma->curr_xfer_len - 1; i++) {
> -		val = tx_word ? *(u16 *) dspi->tx : *(u8 *) dspi->tx;
> +		if (tx_word)
> +			val = *(u16 *) dspi->tx;
> +		else
> +			val = *(u8 *) dspi->tx;
>  		dspi->dma->tx_dma_buf[i] =
>  			SPI_PUSHR_TXDATA(val) | SPI_PUSHR_PCS(dspi->cs) |
>  			SPI_PUSHR_CTAS(0) | SPI_PUSHR_CONT;
>  		dspi->tx += tx_word + 1;
>  	}
>  
> -	val = tx_word ? *(u16 *) dspi->tx : *(u8 *) dspi->tx;
> +	if (tx_word)
> +		val = *(u16 *) dspi->tx;
> +	else
> +		val = *(u8 *) dspi->tx;
>  	dspi->dma->tx_dma_buf[i] = SPI_PUSHR_TXDATA(val) |
>  					SPI_PUSHR_PCS(dspi->cs) |
>  					SPI_PUSHR_CTAS(0);
> @@ -430,9 +438,11 @@ static int dspi_request_dma(struct fsl_dspi
> *dspi, phys_addr_t phy_addr)
>  	return 0;
>  
>  err_slave_config:
> -	devm_kfree(dev, dma->rx_dma_buf);
> +	dma_free_coherent(dev, DSPI_DMA_BUFSIZE,
> +			dma->rx_dma_buf, dma->rx_dma_phys);
>  err_rx_dma_buf:
> -	devm_kfree(dev, dma->tx_dma_buf);
> +	dma_free_coherent(dev, DSPI_DMA_BUFSIZE,
> +			dma->tx_dma_buf, dma->tx_dma_phys);
>  err_tx_dma_buf:
>  	dma_release_channel(dma->chan_tx);
>  err_tx_channel:
--
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Re: [PATCH v2 4/4] spi: spi-fsl-dspi: Minor code cleanup and error path fixes

[maitysanchayan]

On 16-11-21 15:22:09, Stefan Agner wrote:
> On 2016-11-20 21:54, Sanchayan Maity wrote:
> > Code cleanup for improving code readability and error path fixes
> > and cleanup removing use of devm_kfree.
> 
> Two things in one, not very nice. Especially the dma_free_coherent is
> really a bug and the other is a cleanup. Can you make a separate patch
> for the bug?
> 
> As for the cleanup, I don't like the one line conditions too, but I
> don't think it is worth a patch. At least the TX path should be solved
> with my suggestion in patch 2.

Agreed.

- Sanchayan.

> 
> --
> Stefan
> 
> > 
> > Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
> > ---
> >  drivers/spi/spi-fsl-dspi.c | 22 ++++++++++++++++------
> >  1 file changed, 16 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
> > index 08882f7..2987a16 100644
> > --- a/drivers/spi/spi-fsl-dspi.c
> > +++ b/drivers/spi/spi-fsl-dspi.c
> > @@ -226,8 +226,10 @@ static void dspi_rx_dma_callback(void *arg)
> >  	if (!(dspi->dataflags & TRAN_STATE_RX_VOID)) {
> >  		for (i = 0; i < dma->curr_xfer_len; i++) {
> >  			d = dspi->dma->rx_dma_buf[i];
> > -			rx_word ? (*(u16 *)dspi->rx = d) :
> > -						(*(u8 *)dspi->rx = d);
> > +			if (rx_word)
> > +				*(u16 *)dspi->rx = d;
> > +			else
> > +				*(u8 *)dspi->rx = d;
> >  			dspi->rx += rx_word + 1;
> >  		}
> >  	}
> > @@ -247,14 +249,20 @@ static int dspi_next_xfer_dma_submit(struct
> > fsl_dspi *dspi)
> >  	tx_word = is_double_byte_mode(dspi);
> >  
> >  	for (i = 0; i < dma->curr_xfer_len - 1; i++) {
> > -		val = tx_word ? *(u16 *) dspi->tx : *(u8 *) dspi->tx;
> > +		if (tx_word)
> > +			val = *(u16 *) dspi->tx;
> > +		else
> > +			val = *(u8 *) dspi->tx;
> >  		dspi->dma->tx_dma_buf[i] =
> >  			SPI_PUSHR_TXDATA(val) | SPI_PUSHR_PCS(dspi->cs) |
> >  			SPI_PUSHR_CTAS(0) | SPI_PUSHR_CONT;
> >  		dspi->tx += tx_word + 1;
> >  	}
> >  
> > -	val = tx_word ? *(u16 *) dspi->tx : *(u8 *) dspi->tx;
> > +	if (tx_word)
> > +		val = *(u16 *) dspi->tx;
> > +	else
> > +		val = *(u8 *) dspi->tx;
> >  	dspi->dma->tx_dma_buf[i] = SPI_PUSHR_TXDATA(val) |
> >  					SPI_PUSHR_PCS(dspi->cs) |
> >  					SPI_PUSHR_CTAS(0);
> > @@ -430,9 +438,11 @@ static int dspi_request_dma(struct fsl_dspi
> > *dspi, phys_addr_t phy_addr)
> >  	return 0;
> >  
> >  err_slave_config:
> > -	devm_kfree(dev, dma->rx_dma_buf);
> > +	dma_free_coherent(dev, DSPI_DMA_BUFSIZE,
> > +			dma->rx_dma_buf, dma->rx_dma_phys);
> >  err_rx_dma_buf:
> > -	devm_kfree(dev, dma->tx_dma_buf);
> > +	dma_free_coherent(dev, DSPI_DMA_BUFSIZE,
> > +			dma->tx_dma_buf, dma->tx_dma_phys);
> >  err_tx_dma_buf:
> >  	dma_release_channel(dma->chan_tx);
> >  err_tx_channel: