From f1e4c916f97f6adc0848515d269b3899661873ce Mon Sep 17 00:00:00 2001 From: Jani Nikula Date: Mon, 11 Apr 2022 17:00:35 +0300 Subject: [PATCH] drm/edid: add EDID block count and size helpers MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add some helpers to figure out the EDID extension block count, block count, size, pointers to blocks. Unfortunately, we'll need to cast away the const in a few places where we actually need to access the data. v3: fix (!edid_extension_block_count(edid) == 0) (kernel test robot) v2: fix s/j/i/ introduced in a rebase Signed-off-by: Jani Nikula Reviewed-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/dc7b0850293d837439fb3914c8a9d81e39018b4b.1649685475.git.jani.nikula@intel.com --- drivers/gpu/drm/drm_edid.c | 80 +++++++++++++++++++++++++++----------- 1 file changed, 57 insertions(+), 23 deletions(-) diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index d2e1c101575d..324ce8467915 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -1568,6 +1568,38 @@ static const struct drm_display_mode edid_4k_modes[] = { /*** DDC fetch and block validation ***/ +static int edid_extension_block_count(const struct edid *edid) +{ + return edid->extensions; +} + +static int edid_block_count(const struct edid *edid) +{ + return edid_extension_block_count(edid) + 1; +} + +static int edid_size_by_blocks(int num_blocks) +{ + return num_blocks * EDID_LENGTH; +} + +static int edid_size(const struct edid *edid) +{ + return edid_size_by_blocks(edid_block_count(edid)); +} + +static const void *edid_block_data(const struct edid *edid, int index) +{ + BUILD_BUG_ON(sizeof(*edid) != EDID_LENGTH); + + return edid + index; +} + +static const void *edid_extension_block_data(const struct edid *edid, int index) +{ + return edid_block_data(edid, index + 1); +} + static const u8 edid_header[] = { 0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00 }; @@ -1654,8 +1686,8 @@ bool drm_edid_are_equal(const struct edid *edid1, const struct edid *edid2) return false; if (edid1) { - edid1_len = EDID_LENGTH * (1 + edid1->extensions); - edid2_len = EDID_LENGTH * (1 + edid2->extensions); + edid1_len = edid_size(edid1); + edid2_len = edid_size(edid2); if (edid1_len != edid2_len) return false; @@ -1865,14 +1897,16 @@ EXPORT_SYMBOL(drm_edid_block_valid); bool drm_edid_is_valid(struct edid *edid) { int i; - u8 *raw = (u8 *)edid; if (!edid) return false; - for (i = 0; i <= edid->extensions; i++) - if (!drm_edid_block_valid(raw + i * EDID_LENGTH, i, true, NULL)) + for (i = 0; i < edid_block_count(edid); i++) { + void *block = (void *)edid_block_data(edid, i); + + if (!drm_edid_block_valid(block, i, true, NULL)) return false; + } return true; } @@ -1885,13 +1919,13 @@ static struct edid *edid_filter_invalid_blocks(const struct edid *edid, int valid_extensions = edid->extensions - invalid_blocks; int i; - new = kmalloc_array(valid_extensions + 1, EDID_LENGTH, GFP_KERNEL); + new = kmalloc(edid_size_by_blocks(valid_extensions + 1), GFP_KERNEL); if (!new) goto out; dest_block = new; - for (i = 0; i <= edid->extensions; i++) { - const void *block = edid + i; + for (i = 0; i < edid_block_count(edid); i++) { + const void *block = edid_block_data(edid, i); if (edid_block_valid(block, i == 0)) memcpy(dest_block++, block, EDID_LENGTH); @@ -2101,7 +2135,7 @@ struct edid *drm_do_get_edid(struct drm_connector *connector, void *context) { enum edid_block_status status; - int j, invalid_blocks = 0; + int i, invalid_blocks = 0; struct edid *edid, *new; edid = drm_get_override_edid(connector); @@ -2133,20 +2167,20 @@ struct edid *drm_do_get_edid(struct drm_connector *connector, goto fail; } - if (edid->extensions == 0) + if (!edid_extension_block_count(edid)) goto ok; - new = krealloc(edid, (edid->extensions + 1) * EDID_LENGTH, GFP_KERNEL); + new = krealloc(edid, edid_size(edid), GFP_KERNEL); if (!new) goto fail; edid = new; - for (j = 1; j <= edid->extensions; j++) { - void *block = edid + j; + for (i = 1; i < edid_block_count(edid); i++) { + void *block = (void *)edid_block_data(edid, i); - status = edid_block_read(block, j, read_block, context); + status = edid_block_read(block, i, read_block, context); - edid_block_status_print(status, block, j); + edid_block_status_print(status, block, i); if (!edid_block_status_valid(status, edid_block_tag(block))) { if (status == EDID_BLOCK_READ_FAIL) @@ -2156,7 +2190,7 @@ struct edid *drm_do_get_edid(struct drm_connector *connector, } if (invalid_blocks) { - connector_bad_edid(connector, edid, edid->extensions + 1); + connector_bad_edid(connector, edid, edid_block_count(edid)); edid = edid_filter_invalid_blocks(edid, invalid_blocks); } @@ -2321,7 +2355,7 @@ EXPORT_SYMBOL(drm_get_edid_switcheroo); */ struct edid *drm_edid_duplicate(const struct edid *edid) { - return kmemdup(edid, (edid->extensions + 1) * EDID_LENGTH, GFP_KERNEL); + return kmemdup(edid, edid_size(edid), GFP_KERNEL); } EXPORT_SYMBOL(drm_edid_duplicate); @@ -2505,8 +2539,8 @@ drm_for_each_detailed_block(const struct edid *edid, detailed_cb *cb, void *clos for (i = 0; i < EDID_DETAILED_TIMINGS; i++) cb(&(edid->detailed_timings[i]), closure); - for (i = 1; i <= edid->extensions; i++) { - const u8 *ext = (const u8 *)edid + (i * EDID_LENGTH); + for (i = 0; i < edid_extension_block_count(edid); i++) { + const u8 *ext = edid_extension_block_data(edid, i); switch (*ext) { case CEA_EXT: @@ -3476,17 +3510,17 @@ const u8 *drm_find_edid_extension(const struct edid *edid, int i; /* No EDID or EDID extensions */ - if (edid == NULL || edid->extensions == 0) + if (!edid || !edid_extension_block_count(edid)) return NULL; /* Find CEA extension */ - for (i = *ext_index; i < edid->extensions; i++) { - edid_ext = (const u8 *)edid + EDID_LENGTH * (i + 1); + for (i = *ext_index; i < edid_extension_block_count(edid); i++) { + edid_ext = edid_extension_block_data(edid, i); if (edid_block_tag(edid_ext) == ext_id) break; } - if (i >= edid->extensions) + if (i >= edid_extension_block_count(edid)) return NULL; *ext_index = i + 1;