Unverified Commit 0c9d0ddd authored by Maxime Ripard's avatar Maxime Ripard
Browse files

drm/vc4: hdmi: Move audio structure offset checks 



The HDMI driver unbind hook doesn't have any ALSA-related code anymore, so
let's move the ALSA sanity checks and comments we have to some other part
of the driver dedicated to ALSA.

Acked-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: default avatarMaxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220711173939.1132294-47-maxime@cerno.tech
parent af8a3b12

drivers/gpu/drm/vc4/vc4_hdmi.c

+20 −20
Original line number Diff line number Diff line
@@ -2076,6 +2076,26 @@ static int vc4_hdmi_audio_init(struct vc4_hdmi *vc4_hdmi) 
	int index, len;

	int ret;



	/*

	 * ASoC makes it a bit hard to retrieve a pointer to the

	 * vc4_hdmi structure. Registering the card will overwrite our

	 * device drvdata with a pointer to the snd_soc_card structure,

	 * which can then be used to retrieve whatever drvdata we want

	 * to associate.

	 *

	 * However, that doesn't fly in the case where we wouldn't

	 * register an ASoC card (because of an old DT that is missing

	 * the dmas properties for example), then the card isn't

	 * registered and the device drvdata wouldn't be set.

	 *

	 * We can deal with both cases by making sure a snd_soc_card

	 * pointer and a vc4_hdmi structure are pointing to the same

	 * memory address, so we can treat them indistinctly without any

	 * issue.

	 */

	BUILD_BUG_ON(offsetof(struct vc4_hdmi_audio, card) != 0);

	BUILD_BUG_ON(offsetof(struct vc4_hdmi, audio) != 0);



	if (!of_find_property(dev->of_node, "dmas", &len) || !len) {

		dev_warn(dev,

			 "'dmas' DT property is missing or empty, no HDMI audio\n");
@@ -3082,26 +3102,6 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data) 
static void vc4_hdmi_unbind(struct device *dev, struct device *master,

			    void *data)

{

	/*

	 * ASoC makes it a bit hard to retrieve a pointer to the

	 * vc4_hdmi structure. Registering the card will overwrite our

	 * device drvdata with a pointer to the snd_soc_card structure,

	 * which can then be used to retrieve whatever drvdata we want

	 * to associate.

	 *

	 * However, that doesn't fly in the case where we wouldn't

	 * register an ASoC card (because of an old DT that is missing

	 * the dmas properties for example), then the card isn't

	 * registered and the device drvdata wouldn't be set.

	 *

	 * We can deal with both cases by making sure a snd_soc_card

	 * pointer and a vc4_hdmi structure are pointing to the same

	 * memory address, so we can treat them indistinctly without any

	 * issue.

	 */

	BUILD_BUG_ON(offsetof(struct vc4_hdmi_audio, card) != 0);

	BUILD_BUG_ON(offsetof(struct vc4_hdmi, audio) != 0);



	pm_runtime_disable(dev);

}