drm/i915/bios: add proper documentation for the Video BIOS Table (VBT)
Add an overview and documentation for the VBT/BDB header structures.
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/3d826d4600688ca3518713776ab5bd8a8fc9f20f.1450702954.git.jani.nikula@intel.com
diff --git a/drivers/gpu/drm/i915/intel_bios.h b/drivers/gpu/drm/i915/intel_bios.h
index 54eac10..2dc46a9 100644
--- a/drivers/gpu/drm/i915/intel_bios.h
+++ b/drivers/gpu/drm/i915/intel_bios.h
@@ -28,22 +28,40 @@
#ifndef _I830_BIOS_H_
#define _I830_BIOS_H_
+/**
+ * struct vbt_header - VBT Header structure
+ * @signature: VBT signature, always starts with "$VBT"
+ * @version: Version of this structure
+ * @header_size: Size of this structure
+ * @vbt_size: Size of VBT (VBT Header, BDB Header and data blocks)
+ * @vbt_checksum: Checksum
+ * @reserved0: Reserved
+ * @bdb_offset: Offset of &struct bdb_header from beginning of VBT
+ * @aim_offset: Offsets of add-in data blocks from beginning of VBT
+ */
struct vbt_header {
- u8 signature[20]; /**< Always starts with 'VBT$' */
- u16 version; /**< decimal */
- u16 header_size; /**< in bytes */
- u16 vbt_size; /**< in bytes */
+ u8 signature[20];
+ u16 version;
+ u16 header_size;
+ u16 vbt_size;
u8 vbt_checksum;
u8 reserved0;
- u32 bdb_offset; /**< from beginning of VBT */
- u32 aim_offset[4]; /**< from beginning of VBT */
+ u32 bdb_offset;
+ u32 aim_offset[4];
} __packed;
+/**
+ * struct bdb_header - BDB Header structure
+ * @signature: BDB signature "BIOS_DATA_BLOCK"
+ * @version: Version of the data block definitions
+ * @header_size: Size of this structure
+ * @bdb_size: Size of BDB (BDB Header and data blocks)
+ */
struct bdb_header {
- u8 signature[16]; /**< Always 'BIOS_DATA_BLOCK' */
- u16 version; /**< decimal */
- u16 header_size; /**< in bytes */
- u16 bdb_size; /**< in bytes */
+ u8 signature[16];
+ u16 version;
+ u16 header_size;
+ u16 bdb_size;
} __packed;
/* strictly speaking, this is a "skip" block, but it has interesting info */