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From: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
To: Chen-Yu Tsai <wenst@chromium.org>
Cc: Philipp Zabel <p.zabel@pengutronix.de>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Hans Verkuil <hverkuil-cisco@xs4all.nl>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Tomasz Figa <tfiga@chromium.org>,
	linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org,
	linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFT 5/7] media: hantro: jpeg: Add COM segment to JPEG header to align image scan
Date: Sun, 26 Dec 2021 13:33:43 -0300	[thread overview]
Message-ID: <YciZZ2hA4uMveN2l@eze-laptop> (raw)
In-Reply-To: <20211224084248.3070568-6-wenst@chromium.org>

Hi,

On Fri, Dec 24, 2021 at 04:42:46PM +0800, Chen-Yu Tsai wrote:
> The JPEG header size is not 64-bit aligned. This makes the driver
> require a bounce buffer for the encoded JPEG image scan output.
> 
> Add a COM (comment) segment to the JPEG header so that the header size
> is a multiple of 64 bits. This will then allow dropping the use of the
> bounce buffer, and instead have the hardware write out to the capture
> buffer directly.
> 
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
> ---
>  drivers/staging/media/hantro/hantro_jpeg.c | 3 +++
>  drivers/staging/media/hantro/hantro_jpeg.h | 2 +-
>  2 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/media/hantro/hantro_jpeg.c b/drivers/staging/media/hantro/hantro_jpeg.c
> index 7d4018bd6876..51e67e5cf86f 100644
> --- a/drivers/staging/media/hantro/hantro_jpeg.c
> +++ b/drivers/staging/media/hantro/hantro_jpeg.c
> @@ -247,6 +247,9 @@ static const unsigned char hantro_jpeg_header[JPEG_HEADER_SIZE] = {
>  	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
>  	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
>  
> +	/* COM */
> +	0xff, 0xfe, 0x00, 0x03, 0x00,
> +
>  	/* SOS */
>  	0xff, 0xda, 0x00, 0x0c, 0x03, 0x01, 0x00, 0x02,
>  	0x11, 0x03, 0x11, 0x00, 0x3f, 0x00,
> diff --git a/drivers/staging/media/hantro/hantro_jpeg.h b/drivers/staging/media/hantro/hantro_jpeg.h
> index f33c492134e4..0b49d0b82caa 100644
> --- a/drivers/staging/media/hantro/hantro_jpeg.h
> +++ b/drivers/staging/media/hantro/hantro_jpeg.h
> @@ -1,6 +1,6 @@
>  /* SPDX-License-Identifier: GPL-2.0+ */
>  
> -#define JPEG_HEADER_SIZE	619
> +#define JPEG_HEADER_SIZE	624

Can we add some compile-time check for the 8-byte alignment,
so this is always enforced?

Perhaps getting rid of the JPEG_HEADER_SIZE macro,
something like this....


@@ -140,7 +140,7 @@ static const unsigned char chroma_ac_table[] = {
  * and we'll use fixed offsets to change the width, height
  * quantization tables, etc.
  */
-static const unsigned char hantro_jpeg_header[JPEG_HEADER_SIZE] = {
+static const unsigned char hantro_jpeg_header[] = {
        /* SOI */
        0xff, 0xd8,

@@ -304,8 +304,13 @@ void hantro_jpeg_header_assemble(struct hantro_jpeg_ctx *ctx)
 {
        char *buf = ctx->buffer;

-       memcpy(buf, hantro_jpeg_header,
-              sizeof(hantro_jpeg_header));
+       /*
+        * THE JPEG buffer is prepended with the JPEG header,
+        * so 64-bit alignment is needed for DMA.
+        */
+       BUILD_BUG_ON(!IS_ALIGNED(sizeof(hantro_jpeg_header), 8));
+
+       memcpy(buf, hantro_jpeg_header, sizeof(hantro_jpeg_header));

Thanks,
Ezequiel

WARNING: multiple messages have this Message-ID
From: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
To: Chen-Yu Tsai <wenst@chromium.org>
Cc: Philipp Zabel <p.zabel@pengutronix.de>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Hans Verkuil <hverkuil-cisco@xs4all.nl>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Tomasz Figa <tfiga@chromium.org>,
	linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org,
	linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFT 5/7] media: hantro: jpeg: Add COM segment to JPEG header to align image scan
Date: Sun, 26 Dec 2021 13:33:43 -0300	[thread overview]
Message-ID: <YciZZ2hA4uMveN2l@eze-laptop> (raw)
In-Reply-To: <20211224084248.3070568-6-wenst@chromium.org>

Hi,

On Fri, Dec 24, 2021 at 04:42:46PM +0800, Chen-Yu Tsai wrote:
> The JPEG header size is not 64-bit aligned. This makes the driver
> require a bounce buffer for the encoded JPEG image scan output.
> 
> Add a COM (comment) segment to the JPEG header so that the header size
> is a multiple of 64 bits. This will then allow dropping the use of the
> bounce buffer, and instead have the hardware write out to the capture
> buffer directly.
> 
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
> ---
>  drivers/staging/media/hantro/hantro_jpeg.c | 3 +++
>  drivers/staging/media/hantro/hantro_jpeg.h | 2 +-
>  2 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/media/hantro/hantro_jpeg.c b/drivers/staging/media/hantro/hantro_jpeg.c
> index 7d4018bd6876..51e67e5cf86f 100644
> --- a/drivers/staging/media/hantro/hantro_jpeg.c
> +++ b/drivers/staging/media/hantro/hantro_jpeg.c
> @@ -247,6 +247,9 @@ static const unsigned char hantro_jpeg_header[JPEG_HEADER_SIZE] = {
>  	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
>  	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
>  
> +	/* COM */
> +	0xff, 0xfe, 0x00, 0x03, 0x00,
> +
>  	/* SOS */
>  	0xff, 0xda, 0x00, 0x0c, 0x03, 0x01, 0x00, 0x02,
>  	0x11, 0x03, 0x11, 0x00, 0x3f, 0x00,
> diff --git a/drivers/staging/media/hantro/hantro_jpeg.h b/drivers/staging/media/hantro/hantro_jpeg.h
> index f33c492134e4..0b49d0b82caa 100644
> --- a/drivers/staging/media/hantro/hantro_jpeg.h
> +++ b/drivers/staging/media/hantro/hantro_jpeg.h
> @@ -1,6 +1,6 @@
>  /* SPDX-License-Identifier: GPL-2.0+ */
>  
> -#define JPEG_HEADER_SIZE	619
> +#define JPEG_HEADER_SIZE	624

Can we add some compile-time check for the 8-byte alignment,
so this is always enforced?

Perhaps getting rid of the JPEG_HEADER_SIZE macro,
something like this....


@@ -140,7 +140,7 @@ static const unsigned char chroma_ac_table[] = {
  * and we'll use fixed offsets to change the width, height
  * quantization tables, etc.
  */
-static const unsigned char hantro_jpeg_header[JPEG_HEADER_SIZE] = {
+static const unsigned char hantro_jpeg_header[] = {
        /* SOI */
        0xff, 0xd8,

@@ -304,8 +304,13 @@ void hantro_jpeg_header_assemble(struct hantro_jpeg_ctx *ctx)
 {
        char *buf = ctx->buffer;

-       memcpy(buf, hantro_jpeg_header,
-              sizeof(hantro_jpeg_header));
+       /*
+        * THE JPEG buffer is prepended with the JPEG header,
+        * so 64-bit alignment is needed for DMA.
+        */
+       BUILD_BUG_ON(!IS_ALIGNED(sizeof(hantro_jpeg_header), 8));
+
+       memcpy(buf, hantro_jpeg_header, sizeof(hantro_jpeg_header));

Thanks,
Ezequiel

_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

  reply	other threads:[~2021-12-26 16:33 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-24  8:42 [PATCH RFT 0/7] media: hantro: jpeg: Various improvements Chen-Yu Tsai
2021-12-24  8:42 ` Chen-Yu Tsai
2021-12-24  8:42 ` [PATCH RFT 1/7] media: hantro: jpeg: Relax register writes before write starting hardware Chen-Yu Tsai
2021-12-24  8:42   ` Chen-Yu Tsai
2021-12-24  8:42 ` [PATCH RFT 2/7] media: hantro: Fix overfill bottom register field name Chen-Yu Tsai
2021-12-24  8:42   ` Chen-Yu Tsai
2021-12-24  8:42 ` [PATCH RFT 3/7] media: hantro: Support cropping visible area for encoders Chen-Yu Tsai
2021-12-24  8:42   ` Chen-Yu Tsai
2021-12-24  8:42 ` [PATCH RFT 4/7] media: hantro: jpeg: Add JFIF APP0 segment to JPEG encoder output Chen-Yu Tsai
2021-12-24  8:42   ` Chen-Yu Tsai
2021-12-24  8:42 ` [PATCH RFT 5/7] media: hantro: jpeg: Add COM segment to JPEG header to align image scan Chen-Yu Tsai
2021-12-24  8:42   ` Chen-Yu Tsai
2021-12-26 16:33   ` Ezequiel Garcia [this message]
2021-12-26 16:33     ` Ezequiel Garcia
2021-12-27  7:33     ` Chen-Yu Tsai
2021-12-27  7:33       ` Chen-Yu Tsai
2021-12-24  8:42 ` [PATCH RFT 6/7] media: hantro: Implement V4L2_CID_JPEG_ACTIVE_MARKER control Chen-Yu Tsai
2021-12-24  8:42   ` Chen-Yu Tsai
2021-12-24  8:42 ` [PATCH RFT 7/7] media: hantro: output encoded JPEG content directly to capture buffers Chen-Yu Tsai
2021-12-24  8:42   ` Chen-Yu Tsai

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