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author | Hans Verkuil <hans.verkuil@cisco.com> | 2018-09-13 03:25:59 -0400 |
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committer | Mauro Carvalho Chehab <mchehab+samsung@kernel.org> | 2018-09-24 09:09:07 -0400 |
commit | b915bf575d5b7774d0f22d57d6c143e07dcaade2 (patch) | |
tree | f9ae6f8c0b3f6402f220ed59304c21ff1dc889dd /include | |
parent | 985cdcb08a0488558d1005139596b64d73bee267 (diff) | |
download | linux-stable-b915bf575d5b7774d0f22d57d6c143e07dcaade2.tar.gz linux-stable-b915bf575d5b7774d0f22d57d6c143e07dcaade2.tar.bz2 linux-stable-b915bf575d5b7774d0f22d57d6c143e07dcaade2.zip |
media: cec: make cec_get_edid_spa_location() an inline function
This function is needed by both V4L2 and CEC, so move this to
cec.h as a static inline since there are no obvious shared
modules between the two subsystems.
This patch, together with the following ones, fixes a
dependency bug: if CEC_CORE is disabled, then building adv7604
(and other HDMI receivers) will fail because an essential
function is now stubbed out.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Cc: <stable@vger.kernel.org> # for v4.17 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Diffstat (limited to 'include')
-rw-r--r-- | include/media/cec.h | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/include/media/cec.h b/include/media/cec.h index ff9847f7f99d..603f2fa08f62 100644 --- a/include/media/cec.h +++ b/include/media/cec.h @@ -461,4 +461,74 @@ static inline void cec_phys_addr_invalidate(struct cec_adapter *adap) cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false); } +/** + * cec_get_edid_spa_location() - find location of the Source Physical Address + * + * @edid: the EDID + * @size: the size of the EDID + * + * This EDID is expected to be a CEA-861 compliant, which means that there are + * at least two blocks and one or more of the extensions blocks are CEA-861 + * blocks. + * + * The returned location is guaranteed to be <= size-2. + * + * This is an inline function since it is used by both CEC and V4L2. + * Ideally this would go in a module shared by both, but it is overkill to do + * that for just a single function. + */ +static inline unsigned int cec_get_edid_spa_location(const u8 *edid, + unsigned int size) +{ + unsigned int blocks = size / 128; + unsigned int block; + u8 d; + + /* Sanity check: at least 2 blocks and a multiple of the block size */ + if (blocks < 2 || size % 128) + return 0; + + /* + * If there are fewer extension blocks than the size, then update + * 'blocks'. It is allowed to have more extension blocks than the size, + * since some hardware can only read e.g. 256 bytes of the EDID, even + * though more blocks are present. The first CEA-861 extension block + * should normally be in block 1 anyway. + */ + if (edid[0x7e] + 1 < blocks) + blocks = edid[0x7e] + 1; + + for (block = 1; block < blocks; block++) { + unsigned int offset = block * 128; + + /* Skip any non-CEA-861 extension blocks */ + if (edid[offset] != 0x02 || edid[offset + 1] != 0x03) + continue; + + /* search Vendor Specific Data Block (tag 3) */ + d = edid[offset + 2] & 0x7f; + /* Check if there are Data Blocks */ + if (d <= 4) + continue; + if (d > 4) { + unsigned int i = offset + 4; + unsigned int end = offset + d; + + /* Note: 'end' is always < 'size' */ + do { + u8 tag = edid[i] >> 5; + u8 len = edid[i] & 0x1f; + + if (tag == 3 && len >= 5 && i + len <= end && + edid[i + 1] == 0x03 && + edid[i + 2] == 0x0c && + edid[i + 3] == 0x00) + return i + 4; + i += len + 1; + } while (i < end); + } + } + return 0; +} + #endif /* _MEDIA_CEC_H */ |