On Fri, May 27, 2022 at 06:24:44PM +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,
> 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>
> Reviewed-by: Tommaso Merciai <tommaso.merciai@xxxxxxxxxxxxxxxxxxxx>
> ---
> v2
> - add some comments about why the 0x80 offset is needed
> drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c | 9 ++++++++-
> 1 file changed, 8 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..c0fd030d0f19 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 +756,13 @@ static unsigned int mxc_jpeg_setup_cfg_stream(void *cfg_stream_vaddr,
> u32 fourcc,
> u16 w, u16 h)
> {
> - unsigned int offset = 0;
> + /*
> + * There is a hardware issue that first 128 bytes of configuration data
> + * can't be loaded correctly.
> + * To avoid this issue, we need to write the configuration from
> + * an offset which should be no less than 0x80 (128 bytes).
> + */
> + unsigned int offset = 0x80;
> u8 *cfg = (u8 *)cfg_stream_vaddr;
> struct mxc_jpeg_sof *sof;
> struct mxc_jpeg_sos *sos;
> --
> 2.36.1
>
Looks good to me!
Thanks,
Tommaso
--
Tommaso Merciai
Embedded Linux Engineer
tommaso.merciai@xxxxxxxxxxxxxxxxxxxx
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