Revert "spi: omap2-mcspi: Set FIFO DMA trigger level to word length"
diff mbox series

Message ID 20190113204905.29795-1-david@lechnology.com
State New, archived
Headers show
Series
  • Revert "spi: omap2-mcspi: Set FIFO DMA trigger level to word length"
Related show

Commit Message

David Lechner Jan. 13, 2019, 8:49 p.m. UTC
This reverts commit b682cffa3ac6d9d9e16e9b413c45caee3b391fab.

That commit breaks displays using tinydrm drivers, such as ili9225.

It causes corruption in the image that is displayed (it looks like only
1/2 of the framebuffer data is sent, the other half of the display
remains blank.)

The following error appears multiple times:

    ili9225 spi1.0: EOW timed out

Eventually, the system locks up without any additional errors.

Cc: Vignesh R <vigneshr@ti.com>
Signed-off-by: David Lechner <david@lechnology.com>
---
 drivers/spi/spi-omap2-mcspi.c | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

Comments

David Lechner Jan. 13, 2019, 8:52 p.m. UTC | #1
CC: OMAP list for good measure

On 1/13/19 2:49 PM, David Lechner wrote:
> This reverts commit b682cffa3ac6d9d9e16e9b413c45caee3b391fab.
> 
> That commit breaks displays using tinydrm drivers, such as ili9225.
> 
> It causes corruption in the image that is displayed (it looks like only
> 1/2 of the framebuffer data is sent, the other half of the display
> remains blank.)
> 
> The following error appears multiple times:
> 
>      ili9225 spi1.0: EOW timed out
> 
> Eventually, the system locks up without any additional errors.
> 
> Cc: Vignesh R <vigneshr@ti.com>
> Signed-off-by: David Lechner <david@lechnology.com>
> ---
>   drivers/spi/spi-omap2-mcspi.c | 26 +++++++++++++++++++-------
>   1 file changed, 19 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
> index 2fd8881fcd65..5a3854ff2e08 100644
> --- a/drivers/spi/spi-omap2-mcspi.c
> +++ b/drivers/spi/spi-omap2-mcspi.c
> @@ -306,7 +306,7 @@ static void omap2_mcspi_set_fifo(const struct spi_device *spi,
>   	struct omap2_mcspi_cs *cs = spi->controller_state;
>   	struct omap2_mcspi *mcspi;
>   	unsigned int wcnt;
> -	int max_fifo_depth, bytes_per_word;
> +	int max_fifo_depth, fifo_depth, bytes_per_word;
>   	u32 chconf, xferlevel;
>   
>   	mcspi = spi_master_get_devdata(master);
> @@ -322,6 +322,10 @@ static void omap2_mcspi_set_fifo(const struct spi_device *spi,
>   		else
>   			max_fifo_depth = OMAP2_MCSPI_MAX_FIFODEPTH;
>   
> +		fifo_depth = gcd(t->len, max_fifo_depth);
> +		if (fifo_depth < 2 || fifo_depth % bytes_per_word != 0)
> +			goto disable_fifo;
> +
>   		wcnt = t->len / bytes_per_word;
>   		if (wcnt > OMAP2_MCSPI_MAX_FIFOWCNT)
>   			goto disable_fifo;
> @@ -329,17 +333,16 @@ static void omap2_mcspi_set_fifo(const struct spi_device *spi,
>   		xferlevel = wcnt << 16;
>   		if (t->rx_buf != NULL) {
>   			chconf |= OMAP2_MCSPI_CHCONF_FFER;
> -			xferlevel |= (bytes_per_word - 1) << 8;
> +			xferlevel |= (fifo_depth - 1) << 8;
>   		}
> -
>   		if (t->tx_buf != NULL) {
>   			chconf |= OMAP2_MCSPI_CHCONF_FFET;
> -			xferlevel |= bytes_per_word - 1;
> +			xferlevel |= fifo_depth - 1;
>   		}
>   
>   		mcspi_write_reg(master, OMAP2_MCSPI_XFERLEVEL, xferlevel);
>   		mcspi_write_chconf0(spi, chconf);
> -		mcspi->fifo_depth = max_fifo_depth;
> +		mcspi->fifo_depth = fifo_depth;
>   
>   		return;
>   	}
> @@ -598,6 +601,7 @@ omap2_mcspi_txrx_dma(struct spi_device *spi, struct spi_transfer *xfer)
>   	struct dma_slave_config	cfg;
>   	enum dma_slave_buswidth width;
>   	unsigned es;
> +	u32			burst;
>   	void __iomem		*chstat_reg;
>   	void __iomem            *irqstat_reg;
>   	int			wait_res;
> @@ -617,14 +621,22 @@ omap2_mcspi_txrx_dma(struct spi_device *spi, struct spi_transfer *xfer)
>   	}
>   
>   	count = xfer->len;
> +	burst = 1;
> +
> +	if (mcspi->fifo_depth > 0) {
> +		if (count > mcspi->fifo_depth)
> +			burst = mcspi->fifo_depth / es;
> +		else
> +			burst = count / es;
> +	}
>   
>   	memset(&cfg, 0, sizeof(cfg));
>   	cfg.src_addr = cs->phys + OMAP2_MCSPI_RX0;
>   	cfg.dst_addr = cs->phys + OMAP2_MCSPI_TX0;
>   	cfg.src_addr_width = width;
>   	cfg.dst_addr_width = width;
> -	cfg.src_maxburst = es;
> -	cfg.dst_maxburst = es;
> +	cfg.src_maxburst = burst;
> +	cfg.dst_maxburst = burst;
>   
>   	rx = xfer->rx_buf;
>   	tx = xfer->tx_buf;
>
Vignesh Raghavendra Jan. 14, 2019, 12:30 p.m. UTC | #2
On 14/01/19 2:19 AM, David Lechner wrote:
> This reverts commit b682cffa3ac6d9d9e16e9b413c45caee3b391fab.
> 
> That commit breaks displays using tinydrm drivers, such as ili9225.
> 
> It causes corruption in the image that is displayed (it looks like only
> 1/2 of the framebuffer data is sent, the other half of the display
> remains blank.)
> 
> The following error appears multiple times:
> 
>     ili9225 spi1.0: EOW timed out
> 
> Eventually, the system locks up without any additional errors.
> 

Oops, that's unfortunate. I see ili9225 is using bits_per_word = 16.
I believe commit b682cffa3ac6d9d broke spi_transfers where 
bits_per_word anything other than 8 bits.
I don't have ili9225 HW but was able emulate this condition using a SPI 
flash as slave on AM335x and successfully reproduced the issue. Could 
you test if this diff[1] helps in fixing the regression without needing
to revert commit b682cffa3ac6d9d?

If below diff does not help, then could you post logs of types of 
spi_transfers being queued by ili9225 driver? I guess you can dump them 
by enabling DEBUG option in tinydrm-helpers.c.
Also which TI SoC are you using?

Sorry for the trouble!

[1]:

Adjust maxburst size of DMA xfer according to the DMA trigger level and word length
instead of just word length


diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index 2fd8881fcd65..6b7edcff0e6b 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -623,8 +623,8 @@ omap2_mcspi_txrx_dma(struct spi_device *spi, struct spi_transfer *xfer)
        cfg.dst_addr = cs->phys + OMAP2_MCSPI_TX0;
        cfg.src_addr_width = width;
        cfg.dst_addr_width = width;
-       cfg.src_maxburst = es;
-       cfg.dst_maxburst = es;
+       cfg.src_maxburst = width / es;
+       cfg.dst_maxburst = width / es;
 
        rx = xfer->rx_buf;
        tx = xfer->tx_buf;

--
Regards
Vignesh



> Cc: Vignesh R <vigneshr@ti.com>
> Signed-off-by: David Lechner <david@lechnology.com>
> ---
>  drivers/spi/spi-omap2-mcspi.c | 26 +++++++++++++++++++-------
>  1 file changed, 19 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
> index 2fd8881fcd65..5a3854ff2e08 100644
> --- a/drivers/spi/spi-omap2-mcspi.c
> +++ b/drivers/spi/spi-omap2-mcspi.c
> @@ -306,7 +306,7 @@ static void omap2_mcspi_set_fifo(const struct spi_device *spi,
>  	struct omap2_mcspi_cs *cs = spi->controller_state;
>  	struct omap2_mcspi *mcspi;
>  	unsigned int wcnt;
> -	int max_fifo_depth, bytes_per_word;
> +	int max_fifo_depth, fifo_depth, bytes_per_word;
>  	u32 chconf, xferlevel;
>  
>  	mcspi = spi_master_get_devdata(master);
> @@ -322,6 +322,10 @@ static void omap2_mcspi_set_fifo(const struct spi_device *spi,
>  		else
>  			max_fifo_depth = OMAP2_MCSPI_MAX_FIFODEPTH;
>  
> +		fifo_depth = gcd(t->len, max_fifo_depth);
> +		if (fifo_depth < 2 || fifo_depth % bytes_per_word != 0)
> +			goto disable_fifo;
> +
>  		wcnt = t->len / bytes_per_word;
>  		if (wcnt > OMAP2_MCSPI_MAX_FIFOWCNT)
>  			goto disable_fifo;
> @@ -329,17 +333,16 @@ static void omap2_mcspi_set_fifo(const struct spi_device *spi,
>  		xferlevel = wcnt << 16;
>  		if (t->rx_buf != NULL) {
>  			chconf |= OMAP2_MCSPI_CHCONF_FFER;
> -			xferlevel |= (bytes_per_word - 1) << 8;
> +			xferlevel |= (fifo_depth - 1) << 8;
>  		}
> -
>  		if (t->tx_buf != NULL) {
>  			chconf |= OMAP2_MCSPI_CHCONF_FFET;
> -			xferlevel |= bytes_per_word - 1;
> +			xferlevel |= fifo_depth - 1;
>  		}
>  
>  		mcspi_write_reg(master, OMAP2_MCSPI_XFERLEVEL, xferlevel);
>  		mcspi_write_chconf0(spi, chconf);
> -		mcspi->fifo_depth = max_fifo_depth;
> +		mcspi->fifo_depth = fifo_depth;
>  
>  		return;
>  	}
> @@ -598,6 +601,7 @@ omap2_mcspi_txrx_dma(struct spi_device *spi, struct spi_transfer *xfer)
>  	struct dma_slave_config	cfg;
>  	enum dma_slave_buswidth width;
>  	unsigned es;
> +	u32			burst;
>  	void __iomem		*chstat_reg;
>  	void __iomem            *irqstat_reg;
>  	int			wait_res;
> @@ -617,14 +621,22 @@ omap2_mcspi_txrx_dma(struct spi_device *spi, struct spi_transfer *xfer)
>  	}
>  
>  	count = xfer->len;
> +	burst = 1;
> +
> +	if (mcspi->fifo_depth > 0) {
> +		if (count > mcspi->fifo_depth)
> +			burst = mcspi->fifo_depth / es;
> +		else
> +			burst = count / es;
> +	}
>  
>  	memset(&cfg, 0, sizeof(cfg));
>  	cfg.src_addr = cs->phys + OMAP2_MCSPI_RX0;
>  	cfg.dst_addr = cs->phys + OMAP2_MCSPI_TX0;
>  	cfg.src_addr_width = width;
>  	cfg.dst_addr_width = width;
> -	cfg.src_maxburst = es;
> -	cfg.dst_maxburst = es;
> +	cfg.src_maxburst = burst;
> +	cfg.dst_maxburst = burst;
>  
>  	rx = xfer->rx_buf;
>  	tx = xfer->tx_buf;
>
David Lechner Jan. 14, 2019, 11:50 p.m. UTC | #3
On 1/14/19 6:30 AM, Vignesh R wrote:
> 
> 
> On 14/01/19 2:19 AM, David Lechner wrote:
>> This reverts commit b682cffa3ac6d9d9e16e9b413c45caee3b391fab.
>>
>> That commit breaks displays using tinydrm drivers, such as ili9225.
>>
>> It causes corruption in the image that is displayed (it looks like only
>> 1/2 of the framebuffer data is sent, the other half of the display
>> remains blank.)
>>
>> The following error appears multiple times:
>>
>>      ili9225 spi1.0: EOW timed out
>>
>> Eventually, the system locks up without any additional errors.
>>
> 
> Oops, that's unfortunate. I see ili9225 is using bits_per_word = 16.
> I believe commit b682cffa3ac6d9d broke spi_transfers where
> bits_per_word anything other than 8 bits.
> I don't have ili9225 HW but was able emulate this condition using a SPI
> flash as slave on AM335x and successfully reproduced the issue. Could
> you test if this diff[1] helps in fixing the regression without needing
> to revert commit b682cffa3ac6d9d?

Yes, this changes fixes the problem. Thanks!

> 
> If below diff does not help, then could you post logs of types of
> spi_transfers being queued by ili9225 driver? I guess you can dump them
> by enabling DEBUG option in tinydrm-helpers.c.
> Also which TI SoC are you using?
> 
I'm using BeagleBone Green, so AM335x as well.
David Lechner Jan. 14, 2019, 11:57 p.m. UTC | #4
On 1/14/19 6:30 AM, Vignesh R wrote:
> 
> On 14/01/19 2:19 AM, David Lechner wrote:
>> This reverts commit b682cffa3ac6d9d9e16e9b413c45caee3b391fab.
>>
>> That commit breaks displays using tinydrm drivers, such as ili9225.
>>
>> It causes corruption in the image that is displayed (it looks like only
>> 1/2 of the framebuffer data is sent, the other half of the display
>> remains blank.)
>>
>> The following error appears multiple times:
>>
>>      ili9225 spi1.0: EOW timed out
>>
>> Eventually, the system locks up without any additional errors.
>>
> Oops, that's unfortunate. I see ili9225 is using bits_per_word = 16.
> I believe commit b682cffa3ac6d9d broke spi_transfers where
> bits_per_word anything other than 8 bits.
> I don't have ili9225 HW but was able emulate this condition using a SPI
> flash as slave on AM335x and successfully reproduced the issue. Could
> you test if this diff[1] helps in fixing the regression without needing
> to revert commit b682cffa3ac6d9d?
> 
> If below diff does not help, then could you post logs of types of
> spi_transfers being queued by ili9225 driver? I guess you can dump them
> by enabling DEBUG option in tinydrm-helpers.c.
> Also which TI SoC are you using?
> 
> Sorry for the trouble!
> 
> [1]:
> 
> Adjust maxburst size of DMA xfer according to the DMA trigger level and word length
> instead of just word length
> 
> 
> diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
> index 2fd8881fcd65..6b7edcff0e6b 100644
> --- a/drivers/spi/spi-omap2-mcspi.c
> +++ b/drivers/spi/spi-omap2-mcspi.c
> @@ -623,8 +623,8 @@ omap2_mcspi_txrx_dma(struct spi_device *spi, struct spi_transfer *xfer)
>          cfg.dst_addr = cs->phys + OMAP2_MCSPI_TX0;
>          cfg.src_addr_width = width;
>          cfg.dst_addr_width = width;
> -       cfg.src_maxburst = es;
> -       cfg.dst_maxburst = es;
> +       cfg.src_maxburst = width / es;
> +       cfg.dst_maxburst = width / es;

Just an observation... won't `width / es` always == 1 because width is always == es?


>   
>          rx = xfer->rx_buf;
>          tx = xfer->tx_buf;
>
Mark Brown Jan. 15, 2019, 12:07 a.m. UTC | #5
On Mon, Jan 14, 2019 at 05:50:34PM -0600, David Lechner wrote:
> On 1/14/19 6:30 AM, Vignesh R wrote:

> > Oops, that's unfortunate. I see ili9225 is using bits_per_word = 16.
> > I believe commit b682cffa3ac6d9d broke spi_transfers where
> > bits_per_word anything other than 8 bits.
> > I don't have ili9225 HW but was able emulate this condition using a SPI
> > flash as slave on AM335x and successfully reproduced the issue. Could
> > you test if this diff[1] helps in fixing the regression without needing
> > to revert commit b682cffa3ac6d9d?

> Yes, this changes fixes the problem. Thanks!

Excellent!  Vignesh, can you post a formal patch please and I'll get it
merged?

Patch
diff mbox series

diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index 2fd8881fcd65..5a3854ff2e08 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -306,7 +306,7 @@  static void omap2_mcspi_set_fifo(const struct spi_device *spi,
 	struct omap2_mcspi_cs *cs = spi->controller_state;
 	struct omap2_mcspi *mcspi;
 	unsigned int wcnt;
-	int max_fifo_depth, bytes_per_word;
+	int max_fifo_depth, fifo_depth, bytes_per_word;
 	u32 chconf, xferlevel;
 
 	mcspi = spi_master_get_devdata(master);
@@ -322,6 +322,10 @@  static void omap2_mcspi_set_fifo(const struct spi_device *spi,
 		else
 			max_fifo_depth = OMAP2_MCSPI_MAX_FIFODEPTH;
 
+		fifo_depth = gcd(t->len, max_fifo_depth);
+		if (fifo_depth < 2 || fifo_depth % bytes_per_word != 0)
+			goto disable_fifo;
+
 		wcnt = t->len / bytes_per_word;
 		if (wcnt > OMAP2_MCSPI_MAX_FIFOWCNT)
 			goto disable_fifo;
@@ -329,17 +333,16 @@  static void omap2_mcspi_set_fifo(const struct spi_device *spi,
 		xferlevel = wcnt << 16;
 		if (t->rx_buf != NULL) {
 			chconf |= OMAP2_MCSPI_CHCONF_FFER;
-			xferlevel |= (bytes_per_word - 1) << 8;
+			xferlevel |= (fifo_depth - 1) << 8;
 		}
-
 		if (t->tx_buf != NULL) {
 			chconf |= OMAP2_MCSPI_CHCONF_FFET;
-			xferlevel |= bytes_per_word - 1;
+			xferlevel |= fifo_depth - 1;
 		}
 
 		mcspi_write_reg(master, OMAP2_MCSPI_XFERLEVEL, xferlevel);
 		mcspi_write_chconf0(spi, chconf);
-		mcspi->fifo_depth = max_fifo_depth;
+		mcspi->fifo_depth = fifo_depth;
 
 		return;
 	}
@@ -598,6 +601,7 @@  omap2_mcspi_txrx_dma(struct spi_device *spi, struct spi_transfer *xfer)
 	struct dma_slave_config	cfg;
 	enum dma_slave_buswidth width;
 	unsigned es;
+	u32			burst;
 	void __iomem		*chstat_reg;
 	void __iomem            *irqstat_reg;
 	int			wait_res;
@@ -617,14 +621,22 @@  omap2_mcspi_txrx_dma(struct spi_device *spi, struct spi_transfer *xfer)
 	}
 
 	count = xfer->len;
+	burst = 1;
+
+	if (mcspi->fifo_depth > 0) {
+		if (count > mcspi->fifo_depth)
+			burst = mcspi->fifo_depth / es;
+		else
+			burst = count / es;
+	}
 
 	memset(&cfg, 0, sizeof(cfg));
 	cfg.src_addr = cs->phys + OMAP2_MCSPI_RX0;
 	cfg.dst_addr = cs->phys + OMAP2_MCSPI_TX0;
 	cfg.src_addr_width = width;
 	cfg.dst_addr_width = width;
-	cfg.src_maxburst = es;
-	cfg.dst_maxburst = es;
+	cfg.src_maxburst = burst;
+	cfg.dst_maxburst = burst;
 
 	rx = xfer->rx_buf;
 	tx = xfer->tx_buf;