forked from Minki/linux
bfd4e1929b
Neatly reduce displayid boilerplate in code. Remove excessive debug logging while at it, no other functional changes. The old displayid iterator becomes unused; remove it as well as make drm_find_displayid_extension() static. Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/fa4b5c790b5bdd82063545a6f209f8e9d78a63a7.1617024940.git.jani.nikula@intel.com
134 lines
2.8 KiB
C
134 lines
2.8 KiB
C
// SPDX-License-Identifier: MIT
|
|
/*
|
|
* Copyright © 2021 Intel Corporation
|
|
*/
|
|
|
|
#include <drm/drm_displayid.h>
|
|
#include <drm/drm_edid.h>
|
|
#include <drm/drm_print.h>
|
|
|
|
static int validate_displayid(const u8 *displayid, int length, int idx)
|
|
{
|
|
int i, dispid_length;
|
|
u8 csum = 0;
|
|
const struct displayid_hdr *base;
|
|
|
|
base = (const struct displayid_hdr *)&displayid[idx];
|
|
|
|
DRM_DEBUG_KMS("base revision 0x%x, length %d, %d %d\n",
|
|
base->rev, base->bytes, base->prod_id, base->ext_count);
|
|
|
|
/* +1 for DispID checksum */
|
|
dispid_length = sizeof(*base) + base->bytes + 1;
|
|
if (dispid_length > length - idx)
|
|
return -EINVAL;
|
|
|
|
for (i = 0; i < dispid_length; i++)
|
|
csum += displayid[idx + i];
|
|
if (csum) {
|
|
DRM_NOTE("DisplayID checksum invalid, remainder is %d\n", csum);
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const u8 *drm_find_displayid_extension(const struct edid *edid,
|
|
int *length, int *idx,
|
|
int *ext_index)
|
|
{
|
|
const u8 *displayid = drm_find_edid_extension(edid, DISPLAYID_EXT, ext_index);
|
|
const struct displayid_hdr *base;
|
|
int ret;
|
|
|
|
if (!displayid)
|
|
return NULL;
|
|
|
|
/* EDID extensions block checksum isn't for us */
|
|
*length = EDID_LENGTH - 1;
|
|
*idx = 1;
|
|
|
|
ret = validate_displayid(displayid, *length, *idx);
|
|
if (ret)
|
|
return NULL;
|
|
|
|
base = (const struct displayid_hdr *)&displayid[*idx];
|
|
*length = *idx + sizeof(*base) + base->bytes;
|
|
|
|
return displayid;
|
|
}
|
|
|
|
void displayid_iter_edid_begin(const struct edid *edid,
|
|
struct displayid_iter *iter)
|
|
{
|
|
memset(iter, 0, sizeof(*iter));
|
|
|
|
iter->edid = edid;
|
|
}
|
|
|
|
static const struct displayid_block *
|
|
displayid_iter_block(const struct displayid_iter *iter)
|
|
{
|
|
const struct displayid_block *block;
|
|
|
|
if (!iter->section)
|
|
return NULL;
|
|
|
|
block = (const struct displayid_block *)&iter->section[iter->idx];
|
|
|
|
if (iter->idx + sizeof(*block) <= iter->length &&
|
|
iter->idx + sizeof(*block) + block->num_bytes <= iter->length &&
|
|
block->num_bytes > 0)
|
|
return block;
|
|
|
|
return NULL;
|
|
}
|
|
|
|
const struct displayid_block *
|
|
__displayid_iter_next(struct displayid_iter *iter)
|
|
{
|
|
const struct displayid_block *block;
|
|
|
|
if (!iter->edid)
|
|
return NULL;
|
|
|
|
if (iter->section) {
|
|
/* current block should always be valid */
|
|
block = displayid_iter_block(iter);
|
|
if (WARN_ON(!block)) {
|
|
iter->section = NULL;
|
|
iter->edid = NULL;
|
|
return NULL;
|
|
}
|
|
|
|
/* next block in section */
|
|
iter->idx += sizeof(*block) + block->num_bytes;
|
|
|
|
block = displayid_iter_block(iter);
|
|
if (block)
|
|
return block;
|
|
}
|
|
|
|
for (;;) {
|
|
iter->section = drm_find_displayid_extension(iter->edid,
|
|
&iter->length,
|
|
&iter->idx,
|
|
&iter->ext_index);
|
|
if (!iter->section) {
|
|
iter->edid = NULL;
|
|
return NULL;
|
|
}
|
|
|
|
iter->idx += sizeof(struct displayid_hdr);
|
|
|
|
block = displayid_iter_block(iter);
|
|
if (block)
|
|
return block;
|
|
}
|
|
}
|
|
|
|
void displayid_iter_end(struct displayid_iter *iter)
|
|
{
|
|
memset(iter, 0, sizeof(*iter));
|
|
}
|