> From: Tommaso Merciai <tommaso.merciai@xxxxxxxxxxxxxxxxxxxx>
> Sent: 2022年5月27日 17:38
> To: Ming Qian <ming.qian@xxxxxxx>
> Cc: mchehab@xxxxxxxxxx; Mirela Rabulea (OSS)
> <mirela.rabulea@xxxxxxxxxxx>; hverkuil-cisco@xxxxxxxxx;
> shawnguo@xxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx;
> festevam@xxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>;
> linux-media@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Subject: [EXT] Re: [PATCH] media: imx-jpeg: Leave a blank space before the
> configuration data
>
> Caution: EXT Email
>
> Hi Ming,
> I think have some comments on the code for this would be nice for the future
>
> On Fri, May 27, 2022 at 03:54:35PM +0800, Ming Qian wrote:
> > There is a hardware bug that it will load the first 128 bytes of
> > configuration data twice, it will led to some configure error.
> > so shift the configuration data 128 bytes, and make the first 128
> > bytes all zero, then hardware will load the 128 zero twice,
>
> From what I've understood you initialize cfg_stm with zeros then you start to
> write the configuration from 0x80 (128 bytes), avoiding the hw issue right?
>
HI Tommaso,
Yes, you're right, there is a hardware bug.
I want to write the configuration data from the offset 0x80,
And set the first 128 bytes to zero.
Then the hardware bug can be avoided.
Ming.
> > and ignore them as garbage.
> > then the configuration data can be loaded correctly
> >
> > Signed-off-by: Ming Qian <ming.qian@xxxxxxx>
> > Reviewed-by: Mirela Rabulea <mirela.rabulea@xxxxxxx>
> > ---
> > drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
> > b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
> > index 734e1b65fbc7..ad4213e020f3 100644
> > --- a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
> > +++ b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
> > @@ -519,6 +519,7 @@ static bool mxc_jpeg_alloc_slot_data(struct
> mxc_jpeg_dev *jpeg,
> > GFP_ATOMIC);
> > if (!cfg_stm)
> > goto err;
> > + memset(cfg_stm, 0, MXC_JPEG_MAX_CFG_STREAM);
> > jpeg->slot_data[slot].cfg_stream_vaddr = cfg_stm;
> >
> > skip_alloc:
> > @@ -755,7 +756,7 @@ static unsigned int mxc_jpeg_setup_cfg_stream(void
> *cfg_stream_vaddr,
> > u32 fourcc,
> > u16 w, u16 h) {
> > - unsigned int offset = 0;
> > + unsigned int offset = 0x80;
> > u8 *cfg = (u8 *)cfg_stream_vaddr;
> > struct mxc_jpeg_sof *sof;
> > struct mxc_jpeg_sos *sos;
> > --
> > 2.36.1
> >
>
> Thanks,
> Tommaso
>
> --
> Tommaso Merciai
> Embedded Linux Engineer
> tommaso.merciai@xxxxxxxxxxxxxxxxxxxx
> __________________________________
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