RE: [EXT] Re: [PATCH 3/4] dmaengine: fsl-edma: support little endian for edma driver

[Peng Ma]

Hi Vinod,

Thank for you reply.
the registers (CHCFG0 - CHCFG15) on big endian socs as fallows:
CHCFG0		0x0
CHCFG1		0x1
CHCFG2		0x2
CHCFG3		0x3
......
CHCFG12		0xC
CHCFG13		0xD
CHCFG14		0xE
CHCFG15		0xF

On little endian socs as fallows:
CHCFG3		0x0
CHCFG2		0x1
CHCFG1		0x2
CHCFG0		0x3
......
CHCFG15		0xC
CHCFG14		0xD
CHCFG13		0xE
CHCFG12		0xF

To fit this map we should add this patch.

Best Regards,
Peng
>-----Original Message-----
>From: Vinod Koul <vkoul@xxxxxxxxxx>
>Sent: 2019年5月21日 12:38
>To: Peng Ma <peng.ma@xxxxxxx>
>Cc: robh+dt@xxxxxxxxxx; shawnguo@xxxxxxxxxx; mark.rutland@xxxxxxx; Leo
>Li <leoyang.li@xxxxxxx>; dan.j.williams@xxxxxxxxx;
>dmaengine@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx;
>linux-kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
>Subject: [EXT] Re: [PATCH 3/4] dmaengine: fsl-edma: support little endian for
>edma driver
>
>Caution: EXT Email
>
>On 06-05-19, 09:03, Peng Ma wrote:
>> improve edma driver to support little endian.
>
>Can you explain a bit more how adding the below lines adds little endian
>support...
>
>>
>> Signed-off-by: Peng Ma <peng.ma@xxxxxxx>
>> ---
>>  drivers/dma/fsl-edma-common.c |    5 +++++
>>  1 files changed, 5 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/dma/fsl-edma-common.c
>> b/drivers/dma/fsl-edma-common.c index 680b2a0..6bf238e 100644
>> --- a/drivers/dma/fsl-edma-common.c
>> +++ b/drivers/dma/fsl-edma-common.c
>> @@ -83,9 +83,14 @@ void fsl_edma_chan_mux(struct fsl_edma_chan
>*fsl_chan,
>>       u32 ch = fsl_chan->vchan.chan.chan_id;
>>       void __iomem *muxaddr;
>>       unsigned int chans_per_mux, ch_off;
>> +     int endian_diff[4] = {3, 1, -1, -3};
>>
>>       chans_per_mux = fsl_chan->edma->n_chans / DMAMUX_NR;
>>       ch_off = fsl_chan->vchan.chan.chan_id % chans_per_mux;
>> +
>> +     if (!fsl_chan->edma->big_endian)
>> +             ch_off += endian_diff[ch_off % 4];
>> +
>>       muxaddr = fsl_chan->edma->muxbase[ch / chans_per_mux];
>>       slot = EDMAMUX_CHCFG_SOURCE(slot);
>>
>> --
>> 1.7.1
>
>--
>~Vinod