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Subject[PATCH RFT 5/7] media: hantro: jpeg: Add COM segment to JPEG header to align image scan
Date
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
#define JPEG_QUANT_SIZE 64

struct hantro_jpeg_ctx {
--
2.34.1.448.ga2b2bfdf31-goog
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