linux-kernel - [PATCH 1/2] media: coda: jpeg: support optimized huffman tables

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Date:   Mon, 23 Mar 2020 15:09:36 +0200
From:   Adrian Ratiu <adrian.ratiu@...labora.com>
To:     Philipp Zabel <p.zabel@...gutronix.de>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        Ezequiel Garcia <ezequiel@...labora.com>, kernel@...labora.com,
        kernel@...gutronix.de, Tim Harvey <tharvey@...eworks.com>
Subject: [PATCH 1/2] media: coda: jpeg: support optimized huffman tables

Each jpeg can have the huffman tables optimized for its specific content
meaning that the table lenghts and values don't match the standard table
of substitutions so there's no reason to hardcode and expect the sandard
lenghts, otherwise we just end up rejecting optimized jpegs altogether.

Tested on CODA960.

Signed-off-by: Adrian Ratiu <adrian.ratiu@...labora.com>
---
 drivers/media/platform/coda/coda-jpeg.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/media/platform/coda/coda-jpeg.c b/drivers/media/platform/coda/coda-jpeg.c
index 6a11b64efb6b..162ba28a6b95 100644
--- a/drivers/media/platform/coda/coda-jpeg.c
+++ b/drivers/media/platform/coda/coda-jpeg.c
@@ -343,7 +343,8 @@ int coda_jpeg_decode_header(struct coda_ctx *ctx, struct vb2_buffer *vb)
 			v4l2_err(&dev->v4l2_dev, "missing Huffman table\n");
 			return -EINVAL;
 		}
-		if (huffman_tables[i].length != ((i & 2) ? 178 : 28)) {
+		if (huffman_tables[i].length < 17 ||
+		    huffman_tables[i].length > 178) {
 			v4l2_err(&dev->v4l2_dev,
 				 "invalid Huffman table %d length: %zu\n",
 				 i, huffman_tables[i].length);
@@ -357,10 +358,12 @@ int coda_jpeg_decode_header(struct coda_ctx *ctx, struct vb2_buffer *vb)
 			return -ENOMEM;
 		ctx->params.jpeg_huff_tab = huff_tab;
 	}
-	memcpy(huff_tab->luma_dc, huffman_tables[0].start, 16 + 12);
-	memcpy(huff_tab->chroma_dc, huffman_tables[1].start, 16 + 12);
-	memcpy(huff_tab->luma_ac, huffman_tables[2].start, 16 + 162);
-	memcpy(huff_tab->chroma_ac, huffman_tables[3].start, 16 + 162);
+
+	memset(huff_tab, 0, sizeof(*huff_tab));
+	memcpy(huff_tab->luma_dc, huffman_tables[0].start, huffman_tables[0].length);
+	memcpy(huff_tab->chroma_dc, huffman_tables[1].start, huffman_tables[1].length);
+	memcpy(huff_tab->luma_ac, huffman_tables[2].start, huffman_tables[2].length);
+	memcpy(huff_tab->chroma_ac, huffman_tables[3].start, huffman_tables[3].length);
 
 	/* check scan header */
 	for (i = 0; i < scan_header.num_components; i++) {
-- 
2.25.2