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From: <Tudor.Ambarus@microchip.com>
To: <Eugen.Hristev@microchip.com>, <vkoul@kernel.org>,
	<robh+dt@kernel.org>, <Ludovic.Desroches@microchip.com>
Cc: <dmaengine@vger.kernel.org>, <devicetree@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, <Nicolas.Ferre@microchip.com>
Subject: Re: [PATCH 4/7] dmaengine: at_xdmac: adapt perid for mem2mem operations
Date: Wed, 23 Sep 2020 05:30:40 +0000	[thread overview]
Message-ID: <520058c4-00a6-bbe3-2b60-93477be982fa@microchip.com> (raw)
In-Reply-To: <20200914140956.221432-5-eugen.hristev@microchip.com>

On 9/14/20 5:09 PM, Eugen Hristev wrote:
> The PERID in the CC register for mem2mem operations must match an unused
> PERID.
> The PERID field is 7 bits, but the selected value is 0x3f.
> On later products we can have more reserved PERIDs for actual peripherals,
> thus this needs to be increased to maximum size.
> Changing the value to 0x7f, which is the maximum for 7 bits field.
> 

Maybe it is worth to explain that for memory-to-memory transfers, PERID
should be set to an unused peripheral ID, and the maximum value seems the
safest. Anyway with or without this addressed, one can add:

Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>

> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
> ---
>  drivers/dma/at_xdmac.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
> index fab19e00a7be..81bb90206092 100644
> --- a/drivers/dma/at_xdmac.c
> +++ b/drivers/dma/at_xdmac.c
> @@ -726,7 +726,7 @@ at_xdmac_interleaved_queue_desc(struct dma_chan *chan,
>  	 * match the one of another channel. If not, it could lead to spurious
>  	 * flag status.
>  	 */
> -	u32			chan_cc = AT_XDMAC_CC_PERID(0x3f)
> +	u32			chan_cc = AT_XDMAC_CC_PERID(0x7f)
>  					| AT_XDMAC_CC_DIF(0)
>  					| AT_XDMAC_CC_SIF(0)
>  					| AT_XDMAC_CC_MBSIZE_SIXTEEN
> @@ -908,7 +908,7 @@ at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
>  	 * match the one of another channel. If not, it could lead to spurious
>  	 * flag status.
>  	 */
> -	u32			chan_cc = AT_XDMAC_CC_PERID(0x3f)
> +	u32			chan_cc = AT_XDMAC_CC_PERID(0x7f)
>  					| AT_XDMAC_CC_DAM_INCREMENTED_AM
>  					| AT_XDMAC_CC_SAM_INCREMENTED_AM
>  					| AT_XDMAC_CC_DIF(0)
> @@ -1014,7 +1014,7 @@ static struct at_xdmac_desc *at_xdmac_memset_create_desc(struct dma_chan *chan,
>  	 * match the one of another channel. If not, it could lead to spurious
>  	 * flag status.
>  	 */
> -	u32			chan_cc = AT_XDMAC_CC_PERID(0x3f)
> +	u32			chan_cc = AT_XDMAC_CC_PERID(0x7f)
>  					| AT_XDMAC_CC_DAM_UBS_AM
>  					| AT_XDMAC_CC_SAM_INCREMENTED_AM
>  					| AT_XDMAC_CC_DIF(0)
> 


  reply	other threads:[~2020-09-23  5:30 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-14 14:09 [PATCH 0/7] dmaengine: add support for sama7g5 based at_xdmac Eugen Hristev
2020-09-14 14:09 ` [PATCH 1/7] dmaengine: at_xdmac: separate register defines into header file Eugen Hristev
2020-09-23  5:07   ` Tudor.Ambarus
2020-09-14 14:09 ` [PATCH 2/7] MAINTAINERS: add dma/at_xdmac_regs.h to XDMAC driver entry Eugen Hristev
2020-09-23  5:12   ` Tudor.Ambarus
2020-09-14 14:09 ` [PATCH 3/7] dt-bindings: dmaengine: at_xdmac: add compatible with microchip,sama7g5 Eugen Hristev
2020-09-22 23:32   ` Rob Herring
2020-09-14 14:09 ` [PATCH 4/7] dmaengine: at_xdmac: adapt perid for mem2mem operations Eugen Hristev
2020-09-23  5:30   ` Tudor.Ambarus [this message]
2020-09-23  5:35     ` Tudor.Ambarus
2020-09-14 14:09 ` [PATCH 5/7] dmaengine: at_xdmac: add support for sama7g5 based at_xdmac Eugen Hristev
2020-09-23  7:08   ` Tudor.Ambarus
2020-10-16  6:52     ` Eugen.Hristev
2020-09-14 14:09 ` [PATCH 6/7] dt-bindings: dmaengine: at_xdmac: add optional microchip,m2m property Eugen Hristev
2020-09-22 23:33   ` Rob Herring
2020-10-16  6:45     ` Eugen.Hristev
2020-10-16  7:06       ` Vinod Koul
2020-10-16  7:09         ` Eugen.Hristev
2020-09-14 14:09 ` [PATCH 7/7] dmaengine: at_xdmac: add AXI priority support and recommended settings Eugen Hristev

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