Re: [PATCH] spi: imx: fix the burst length at DMA mode and CPU mode

[Carlos Song]

> -----Original Message-----
> From: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
> Sent: Wednesday, January 31, 2024 4:08 PM
> To: Carlos Song <carlos.song@xxxxxxx>
> Cc: broonie@xxxxxxxxxx; shawnguo@xxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx;
> kernel@xxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>; benjamin@xxxxxxxxxx;
> stefanmoring@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-spi@xxxxxxxxxxxxxxx
> Subject: [EXT] Re: [PATCH] spi: imx: fix the burst length at DMA mode and CPU
> mode
> 
> On 31.01.2024 10:46:23, carlos.song@xxxxxxx wrote:
> > From: Carlos Song <carlos.song@xxxxxxx>
> >
> > For DMA mode, the bus width of the DMA is equal to the size of data
> > word, so burst length should be configured as bits per word.
> >
> > For CPU mode, because of the spi transfer len is in byte, so burst
> > length should be configured as bits per byte * spi_imx->count.
> >
> > Signed-off-by: Carlos Song <carlos.song@xxxxxxx>
> > Reviewed-by: Clark Wang <xiaoning.wang@xxxxxxx>
> > Fixes: e9b220aeacf1 ("spi: spi-imx: correctly configure burst length
> > when using dma")
> > Fixes: 5f66db08cbd3 ("spi: imx: Take in account bits per word instead
> > of assuming 8-bits")
> > ---
> >  drivers/spi/spi-imx.c | 9 ++++-----
> >  1 file changed, 4 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c index
> > 546cdce525fc..b4ade2d53fef 100644
> > --- a/drivers/spi/spi-imx.c
> > +++ b/drivers/spi/spi-imx.c
> > @@ -54,7 +54,7 @@ MODULE_PARM_DESC(polling_limit_us,
> >  #define MX51_ECSPI_CTRL_MAX_BURST	512
> >  /* The maximum bytes that IMX53_ECSPI can transfer in target mode.*/
> >  #define MX53_MAX_TRANSFER_BYTES		512
> > -
> > +#define BITS_PER_BYTE	8
> 

It will be removed and I will send patch V2.
Thank you!

BR
Carlos

> That's already defined in linux/bits.h
> 
> regards,
> Marc
> 
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