[PATCH] dmaengine: edma: Align the memcpy acnt array size with the transfer

[PATCH] dmaengine: edma: Align the memcpy acnt array size with the transfer

[Peter Ujfalusi]

?Memory to Memory transfers does not have any special alignment needs
regarding to acnt array size, but if one of the areas are in memory mapped
regions (like PCIe memory), we need to make sure that the acnt array size
is aligned with the mem copy parameters.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
 drivers/dma/edma.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index 14c52574262c..2f880010297d 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -1169,11 +1169,24 @@ static struct dma_async_tx_descriptor *edma_prep_dma_memcpy(
 	struct edma_desc *edesc;
 	struct device *dev = chan->device->dev;
 	struct edma_chan *echan = to_edma_chan(chan);
-	unsigned int width, pset_len;
+	unsigned int width, pset_len, array_size;
 
 	if (unlikely(!echan || !len))
 		return NULL;
 
+	/* Align the array size (acnt block) with the transfer properties */
+	switch (__ffs((src | dest | len))) {
+	case 0:
+		array_size = SZ_32K - 1;
+		break;
+	case 1:
+		array_size = SZ_32K - 2;
+		break;
+	default:
+		array_size = SZ_32K - 4;
+		break;
+	}
+
 	if (len < SZ_64K) {
 		/*
 		 * Transfer size less than 64K can be handled with one paRAM
@@ -1195,7 +1208,7 @@ static struct dma_async_tx_descriptor *edma_prep_dma_memcpy(
 		 * When the full_length is multibple of 32767 one slot can be
 		 * used to complete the transfer.
 		 */
-		width = SZ_32K - 1;
+		width = array_size;
 		pset_len = rounddown(len, width);
 		/* One slot is enough for lengths multiple of (SZ_32K -1) */
 		if (unlikely(pset_len == len))
@@ -1243,7 +1256,7 @@ static struct dma_async_tx_descriptor *edma_prep_dma_memcpy(
 		}
 		dest += pset_len;
 		src += pset_len;
-		pset_len = width = len % (SZ_32K - 1);
+		pset_len = width = len % array_size;
 
 		ret = edma_config_pset(chan, &edesc->pset[1], src, dest, 1,
 				       width, pset_len, DMA_MEM_TO_MEM);
-- 
2.14.1


Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

[PATCH] dmaengine: edma: Align the memcpy acnt array size with the transfer

[Greg KH]

On Fri, Sep 15, 2017 at 10:23:28AM +0300, Peter Ujfalusi wrote:
> ?Memory to Memory transfers does not have any special alignment needs
> regarding to acnt array size, but if one of the areas are in memory mapped
> regions (like PCIe memory), we need to make sure that the acnt array size
> is aligned with the mem copy parameters.
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> ---
>  drivers/dma/edma.c | 19 ++++++++++++++++---
>  1 file changed, 16 insertions(+), 3 deletions(-)

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>

[PATCH] dmaengine: edma: Align the memcpy acnt array size with the transfer

[Peter Ujfalusi]

?
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

On 09/15/2017 07:47 PM, Greg KH wrote:
> On Fri, Sep 15, 2017 at 10:23:28AM +0300, Peter Ujfalusi wrote:
>> ?Memory to Memory transfers does not have any special alignment needs
>> regarding to acnt array size, but if one of the areas are in memory mapped
>> regions (like PCIe memory), we need to make sure that the acnt array size
>> is aligned with the mem copy parameters.
>>
>> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
>> ---
>>  drivers/dma/edma.c | 19 ++++++++++++++++---
>>  1 file changed, 16 insertions(+), 3 deletions(-)
> 
> <formletter>
> 
> This is not the correct way to submit patches for inclusion in the
> stable kernel tree.  Please read:
>     https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> for how to do this properly.
> 
> </formletter>

Sorry, I forgot to add the CC to the patch itself. I will resend it with the
correct form.

-- 
P?ter