drm/i915/bios: have get_blocksize() support MIPI sequence block v3+

Have get_blocksize() support the special case of MIPI sequence block v3+
which has a separate field for size. Provide and use abstractions for
getting the blocksize given a pointer to the block "envelope",
i.e. pointer to the block id, and given a pointer to the block payload
data.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/e935bd5e119a83dd91214c47e6cd4f6ce8b2a17e.1450702954.git.jani.nikula@intel.com

diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 5ea6087c40c1aef9fcbffe7c3354a42e704538aa..961ae7f6d075469f0726516579530328bf9f3c06 100644 (file)
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -58,6 +58,22 @@
 
 static int panel_type;
 
+/* Get BDB block size given a pointer to Block ID. */
+static u32 _get_blocksize(const u8 *block_base)
+{
+       /* The MIPI Sequence Block v3+ has a separate size field. */
+       if (*block_base == BDB_MIPI_SEQUENCE && *(block_base + 3) >= 3)
+               return *((const u32 *)(block_base + 4));
+       else
+               return *((const u16 *)(block_base + 1));
+}
+
+/* Get BDB block size give a pointer to data after Block ID and Block Size. */
+static u32 get_blocksize(const void *block_data)
+{
+       return _get_blocksize(block_data - 3);
+}
+
 static const void *
 find_section(const void *_bdb, int section_id)
 {
@@ -74,14 +90,8 @@ find_section(const void *_bdb, int section_id)
        /* walk the sections looking for section_id */
        while (index + 3 < total) {
                current_id = *(base + index);
-               index++;
-
-               current_size = *((const u16 *)(base + index));
-               index += 2;
-
-               /* The MIPI Sequence Block v3+ has a separate size field. */
-               if (current_id == BDB_MIPI_SEQUENCE && *(base + index) >= 3)
-                       current_size = *((const u32 *)(base + index + 1));
+               current_size = _get_blocksize(base + index);
+               index += 3;
 
                if (index + current_size > total)
                        return NULL;
@@ -95,16 +105,6 @@ find_section(const void *_bdb, int section_id)
        return NULL;
 }
 
-static u16
-get_blocksize(const void *p)
-{
-       u16 *block_ptr, block_size;
-
-       block_ptr = (u16 *)((char *)p - 2);
-       block_size = *block_ptr;
-       return block_size;
-}
-
 static void
 fill_detail_timing_data(struct drm_display_mode *panel_fixed_mode,
                        const struct lvds_dvo_timing *dvo_timing)