Commit a1789b3f authored by Jani Nikula's avatar Jani Nikula
Browse files

drm/i915/bios: abstract child device expected size 



Add a function to return the expected child device size. Flip the if
ladder around and use the same versions as in documentation to make it
easier to verify. Return an error for unknown versions. No functional
changes.

v2: Move BUILD_BUG_ON() next to the expected sizes

Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240226175854.287871-3-jani.nikula@intel.com


Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
parent e396a06e

drivers/gpu/drm/i915/display/intel_bios.c

+24 −16
Original line number Diff line number Diff line
@@ -2699,27 +2699,35 @@ static void parse_ddi_ports(struct drm_i915_private *i915) 
		print_ddi_port(devdata);

}



static int child_device_expected_size(u16 version)

{

	BUILD_BUG_ON(sizeof(struct child_device_config) < 40);



	if (version > 256)

		return -ENOENT;

	else if (version >= 256)

		return 40;

	else if (version >= 216)

		return 39;

	else if (version >= 196)

		return 38;

	else if (version >= 195)

		return 37;

	else if (version >= 111)

		return LEGACY_CHILD_DEVICE_CONFIG_SIZE;

	else if (version >= 106)

		return 27;

	else

		return 22;

}



static bool child_device_size_valid(struct drm_i915_private *i915, int size)

{

	int expected_size;



	if (i915->display.vbt.version < 106) {

		expected_size = 22;

	} else if (i915->display.vbt.version < 111) {

		expected_size = 27;

	} else if (i915->display.vbt.version < 195) {

		expected_size = LEGACY_CHILD_DEVICE_CONFIG_SIZE;

	} else if (i915->display.vbt.version == 195) {

		expected_size = 37;

	} else if (i915->display.vbt.version <= 215) {

		expected_size = 38;

	} else if (i915->display.vbt.version <= 255) {

		expected_size = 39;

	} else if (i915->display.vbt.version <= 256) {

		expected_size = 40;

	} else {

	expected_size = child_device_expected_size(i915->display.vbt.version);

	if (expected_size < 0) {

		expected_size = sizeof(struct child_device_config);

		BUILD_BUG_ON(sizeof(struct child_device_config) < 40);

		drm_dbg(&i915->drm,

			"Expected child device config size for VBT version %u not known; assuming %d\n",

			i915->display.vbt.version, expected_size);