From: Alexandre Courbot <acourbot@chromium.org> To: Hans Verkuil <hverkuil@xs4all.nl> Cc: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>, Linux Media Mailing List <linux-media@vger.kernel.org>, "moderated list:ARM/Mediatek SoC support" <linux-mediatek@lists.infradead.org>, LKML <linux-kernel@vger.kernel.org>, kernel@collabora.com, Enric Balletbo i Serra <enric.balletbo@collabora.com>, Dafna Hirschfeld <dafna3@gmail.com>, Tiffany Lin <tiffany.lin@mediatek.com>, Andrew-CT Chen <andrew-ct.chen@mediatek.com>, minghsiu.tsai@mediatek.com, houlong.wei@mediatek.com, Mauro Carvalho Chehab <mchehab@kernel.org>, Matthias Brugger <matthias.bgg@gmail.com> Subject: Re: [PATCH v4] media: mtk-vpu: Ensure alignment of 8 for DTCM buffer Date: Mon, 18 Oct 2021 10:16:54 +0900 [thread overview] Message-ID: <CAPBb6MW_i1_Lh2ZaF8jGjcV-4XBhjswtyKkZCk3HxKO7LX79Og@mail.gmail.com> (raw) In-Reply-To: <c59b7f40-d99e-370a-b797-5dc72979df46@xs4all.nl> Hi Hans! On Mon, Oct 4, 2021 at 6:37 PM Hans Verkuil <hverkuil@xs4all.nl> wrote: > > On 20/09/2021 19:04, Dafna Hirschfeld wrote: > > From: Alexandre Courbot <acourbot@chromium.org> > > > > When running memcpy_toio: > > memcpy_toio(send_obj->share_buf, buf, len); > > it was found that errors appear if len is not a multiple of 8: > > > > [58.350841] mtk-mdp 14001000.rdma: processing failed: -22 > > Why do errors appear? Is that due to a HW bug? Some other reason? MTK folks would be the best placed to answer this, but since the failure is reported by the firmware I'd suspect either a firmware or hardware limitation. > > > > > This patch ensures the copy of a multiple of 8 size by calling > > round_up(len, 8) when copying > > > > Fixes: e6599adfad30 ("media: mtk-vpu: avoid unaligned access to DTCM buffer.") > > Signed-off-by: Alexandre Courbot <acourbot@chromium.org> > > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> > > Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com> > > Reviewed-by: Houlong Wei <houlong.wei@mediatek.com> > > --- > > changes since v3: > > 1. multile -> multiple > > 2. add inline doc > > > > changes since v2: > > 1. do the extra copy only if len is not multiple of 8 > > > > changes since v1: > > 1. change sign-off-by tags > > 2. change values to memset > > > > drivers/media/platform/mtk-vpu/mtk_vpu.c | 15 ++++++++++++++- > > 1 file changed, 14 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/media/platform/mtk-vpu/mtk_vpu.c b/drivers/media/platform/mtk-vpu/mtk_vpu.c > > index ec290dde59cf..1df031716c8f 100644 > > --- a/drivers/media/platform/mtk-vpu/mtk_vpu.c > > +++ b/drivers/media/platform/mtk-vpu/mtk_vpu.c > > @@ -349,7 +349,20 @@ int vpu_ipi_send(struct platform_device *pdev, > > } > > } while (vpu_cfg_readl(vpu, HOST_TO_VPU)); > > > > - memcpy_toio(send_obj->share_buf, buf, len); > > + /* > > + * when copying data to the vpu hardware, the memcpy_toio operation must copy > > + * a multiple of 8. Otherwise the processing fails > > Same here: it needs to explain why the processing fails. > > > + */ > > + if (len % 8 != 0) { > > + unsigned char data[SHARE_BUF_SIZE]; > > Wouldn't it be more robust if you say: > > unsigned char data[sizeof(send_obj->share_buf)]; Definitely yes. > > I also think that the SHARE_BUF_SIZE define needs a comment stating that it must be a > multiple of 8, otherwise unexpected things can happen. > > You also noticed that the current SHARE_BUF_SIZE define is too low, but I saw > no patch correcting this. Shouldn't that be fixed as well? AFAICT the firmware expects this exact size on its end, so I don't believe it can be changed that easily. But maybe someone from MTK can prove me wrong. Cheers, Alex.
WARNING: multiple messages have this Message-ID (diff)
From: Alexandre Courbot <acourbot@chromium.org> To: Hans Verkuil <hverkuil@xs4all.nl> Cc: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>, Linux Media Mailing List <linux-media@vger.kernel.org>, "moderated list:ARM/Mediatek SoC support" <linux-mediatek@lists.infradead.org>, LKML <linux-kernel@vger.kernel.org>, kernel@collabora.com, Enric Balletbo i Serra <enric.balletbo@collabora.com>, Dafna Hirschfeld <dafna3@gmail.com>, Tiffany Lin <tiffany.lin@mediatek.com>, Andrew-CT Chen <andrew-ct.chen@mediatek.com>, minghsiu.tsai@mediatek.com, houlong.wei@mediatek.com, Mauro Carvalho Chehab <mchehab@kernel.org>, Matthias Brugger <matthias.bgg@gmail.com> Subject: Re: [PATCH v4] media: mtk-vpu: Ensure alignment of 8 for DTCM buffer Date: Mon, 18 Oct 2021 10:16:54 +0900 [thread overview] Message-ID: <CAPBb6MW_i1_Lh2ZaF8jGjcV-4XBhjswtyKkZCk3HxKO7LX79Og@mail.gmail.com> (raw) In-Reply-To: <c59b7f40-d99e-370a-b797-5dc72979df46@xs4all.nl> Hi Hans! On Mon, Oct 4, 2021 at 6:37 PM Hans Verkuil <hverkuil@xs4all.nl> wrote: > > On 20/09/2021 19:04, Dafna Hirschfeld wrote: > > From: Alexandre Courbot <acourbot@chromium.org> > > > > When running memcpy_toio: > > memcpy_toio(send_obj->share_buf, buf, len); > > it was found that errors appear if len is not a multiple of 8: > > > > [58.350841] mtk-mdp 14001000.rdma: processing failed: -22 > > Why do errors appear? Is that due to a HW bug? Some other reason? MTK folks would be the best placed to answer this, but since the failure is reported by the firmware I'd suspect either a firmware or hardware limitation. > > > > > This patch ensures the copy of a multiple of 8 size by calling > > round_up(len, 8) when copying > > > > Fixes: e6599adfad30 ("media: mtk-vpu: avoid unaligned access to DTCM buffer.") > > Signed-off-by: Alexandre Courbot <acourbot@chromium.org> > > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> > > Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com> > > Reviewed-by: Houlong Wei <houlong.wei@mediatek.com> > > --- > > changes since v3: > > 1. multile -> multiple > > 2. add inline doc > > > > changes since v2: > > 1. do the extra copy only if len is not multiple of 8 > > > > changes since v1: > > 1. change sign-off-by tags > > 2. change values to memset > > > > drivers/media/platform/mtk-vpu/mtk_vpu.c | 15 ++++++++++++++- > > 1 file changed, 14 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/media/platform/mtk-vpu/mtk_vpu.c b/drivers/media/platform/mtk-vpu/mtk_vpu.c > > index ec290dde59cf..1df031716c8f 100644 > > --- a/drivers/media/platform/mtk-vpu/mtk_vpu.c > > +++ b/drivers/media/platform/mtk-vpu/mtk_vpu.c > > @@ -349,7 +349,20 @@ int vpu_ipi_send(struct platform_device *pdev, > > } > > } while (vpu_cfg_readl(vpu, HOST_TO_VPU)); > > > > - memcpy_toio(send_obj->share_buf, buf, len); > > + /* > > + * when copying data to the vpu hardware, the memcpy_toio operation must copy > > + * a multiple of 8. Otherwise the processing fails > > Same here: it needs to explain why the processing fails. > > > + */ > > + if (len % 8 != 0) { > > + unsigned char data[SHARE_BUF_SIZE]; > > Wouldn't it be more robust if you say: > > unsigned char data[sizeof(send_obj->share_buf)]; Definitely yes. > > I also think that the SHARE_BUF_SIZE define needs a comment stating that it must be a > multiple of 8, otherwise unexpected things can happen. > > You also noticed that the current SHARE_BUF_SIZE define is too low, but I saw > no patch correcting this. Shouldn't that be fixed as well? AFAICT the firmware expects this exact size on its end, so I don't believe it can be changed that easily. But maybe someone from MTK can prove me wrong. Cheers, Alex. _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek
next prev parent reply other threads:[~2021-10-18 1:17 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-09-20 17:04 [PATCH v4] media: mtk-vpu: Ensure alignment of 8 for DTCM buffer Dafna Hirschfeld 2021-09-20 17:04 ` Dafna Hirschfeld 2021-10-04 9:37 ` Hans Verkuil 2021-10-04 9:37 ` Hans Verkuil 2021-10-18 1:16 ` Alexandre Courbot [this message] 2021-10-18 1:16 ` Alexandre Courbot 2021-10-18 7:07 ` Dafna Hirschfeld 2021-10-18 7:07 ` Dafna Hirschfeld 2021-11-03 8:03 ` houlong wei 2021-11-03 8:03 ` houlong wei 2021-11-03 9:19 ` Irui Wang 2021-11-03 9:19 ` Irui Wang 2021-11-03 11:04 ` Dafna Hirschfeld 2021-11-03 11:04 ` Dafna Hirschfeld 2021-11-09 8:46 ` Dafna Hirschfeld 2021-11-09 8:46 ` Dafna Hirschfeld 2021-11-10 3:11 ` Irui Wang 2021-11-10 3:11 ` Irui Wang 2021-11-29 8:11 ` Dafna Hirschfeld 2021-11-29 8:11 ` Dafna Hirschfeld 2021-11-29 14:39 ` Dafna Hirschfeld 2021-11-29 14:39 ` Dafna Hirschfeld 2021-12-06 7:23 ` Alexandre Courbot 2021-12-06 7:23 ` Alexandre Courbot 2022-02-15 9:41 ` AngeloGioacchino Del Regno 2022-02-15 9:41 ` AngeloGioacchino Del Regno
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