Commit 6537f79a authored by Jani Nikula's avatar Jani Nikula
Browse files

drm/edid: add new interfaces around struct drm_edid 



Add new functions drm_edid_read(), drm_edid_read_ddc(), and
drm_edid_read_custom() to replace drm_get_edid() and drm_do_get_edid()
for reading the EDID. The transition is expected to happen over a fairly
long time.

Note that the new drm_edid_read*() functions do not do any of the
connector updates anymore. The reading and parsing will be completely
separated from each other.

Add new functions drm_edid_alloc(), drm_edid_dup(), and drm_edid_free()
for allocating and freeing drm_edid containers.

Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/5a6532a94cad6a79424f6d1918dbe7b7d607ac03.1654674560.git.jani.nikula@intel.com
parent 407d63b3

drivers/gpu/drm/drm_edid.c

+221 −24
Original line number Diff line number Diff line
@@ -2226,29 +2226,9 @@ static enum edid_block_status edid_block_read(void *block, unsigned int block_nu 
	return status;

}



/**

 * drm_do_get_edid - get EDID data using a custom EDID block read function

 * @connector: connector we're probing

 * @read_block: EDID block read function

 * @context: private data passed to the block read function

 *

 * When the I2C adapter connected to the DDC bus is hidden behind a device that

 * exposes a different interface to read EDID blocks this function can be used

 * to get EDID data using a custom block read function.

 *

 * As in the general case the DDC bus is accessible by the kernel at the I2C

 * level, drivers must make all reasonable efforts to expose it as an I2C

 * adapter and use drm_get_edid() instead of abusing this function.

 *

 * The EDID may be overridden using debugfs override_edid or firmware EDID

 * (drm_load_edid_firmware() and drm.edid_firmware parameter), in this priority

 * order. Having either of them bypasses actual EDID reads.

 *

 * Return: Pointer to valid EDID or NULL if we couldn't find any.

 */

struct edid *drm_do_get_edid(struct drm_connector *connector,

			     read_block_fn read_block,

			     void *context)

static struct edid *_drm_do_get_edid(struct drm_connector *connector,

				     read_block_fn read_block, void *context,

				     size_t *size)

{

	enum edid_block_status status;

	int i, invalid_blocks = 0;
@@ -2315,14 +2295,125 @@ struct edid *drm_do_get_edid(struct drm_connector *connector, 
	}



ok:

	if (size)

		*size = alloc_size;



	return edid;



fail:

	kfree(edid);

	return NULL;

}



/**

 * drm_do_get_edid - get EDID data using a custom EDID block read function

 * @connector: connector we're probing

 * @read_block: EDID block read function

 * @context: private data passed to the block read function

 *

 * When the I2C adapter connected to the DDC bus is hidden behind a device that

 * exposes a different interface to read EDID blocks this function can be used

 * to get EDID data using a custom block read function.

 *

 * As in the general case the DDC bus is accessible by the kernel at the I2C

 * level, drivers must make all reasonable efforts to expose it as an I2C

 * adapter and use drm_get_edid() instead of abusing this function.

 *

 * The EDID may be overridden using debugfs override_edid or firmware EDID

 * (drm_load_edid_firmware() and drm.edid_firmware parameter), in this priority

 * order. Having either of them bypasses actual EDID reads.

 *

 * Return: Pointer to valid EDID or NULL if we couldn't find any.

 */

struct edid *drm_do_get_edid(struct drm_connector *connector,

			     read_block_fn read_block,

			     void *context)

{

	return _drm_do_get_edid(connector, read_block, context, NULL);

}

EXPORT_SYMBOL_GPL(drm_do_get_edid);



/* Allocate struct drm_edid container *without* duplicating the edid data */

static const struct drm_edid *_drm_edid_alloc(const void *edid, size_t size)

{

	struct drm_edid *drm_edid;



	if (!edid || !size || size < EDID_LENGTH)

		return NULL;



	drm_edid = kzalloc(sizeof(*drm_edid), GFP_KERNEL);

	if (drm_edid) {

		drm_edid->edid = edid;

		drm_edid->size = size;

	}



	return drm_edid;

}



/**

 * drm_edid_alloc - Allocate a new drm_edid container

 * @edid: Pointer to raw EDID data

 * @size: Size of memory allocated for EDID

 *

 * Allocate a new drm_edid container. Do not calculate edid size from edid, pass

 * the actual size that has been allocated for the data. There is no validation

 * of the raw EDID data against the size, but at least the EDID base block must

 * fit in the buffer.

 *

 * The returned pointer must be freed using drm_edid_free().

 *

 * Return: drm_edid container, or NULL on errors

 */

const struct drm_edid *drm_edid_alloc(const void *edid, size_t size)

{

	const struct drm_edid *drm_edid;



	if (!edid || !size || size < EDID_LENGTH)

		return NULL;



	edid = kmemdup(edid, size, GFP_KERNEL);

	if (!edid)

		return NULL;



	drm_edid = _drm_edid_alloc(edid, size);

	if (!drm_edid)

		kfree(edid);



	return drm_edid;

}

EXPORT_SYMBOL(drm_edid_alloc);



/**

 * drm_edid_dup - Duplicate a drm_edid container

 * @drm_edid: EDID to duplicate

 *

 * The returned pointer must be freed using drm_edid_free().

 *

 * Returns: drm_edid container copy, or NULL on errors

 */

const struct drm_edid *drm_edid_dup(const struct drm_edid *drm_edid)

{

	if (!drm_edid)

		return NULL;



	return drm_edid_alloc(drm_edid->edid, drm_edid->size);

}

EXPORT_SYMBOL(drm_edid_dup);



/**

 * drm_edid_free - Free the drm_edid container

 * @drm_edid: EDID to free

 */

void drm_edid_free(const struct drm_edid *drm_edid)

{

	if (!drm_edid)

		return;



	kfree(drm_edid->edid);

	kfree(drm_edid);

}

EXPORT_SYMBOL(drm_edid_free);



/**

 * drm_probe_ddc() - probe DDC presence

 * @adapter: I2C adapter to probe
@@ -2359,12 +2450,118 @@ struct edid *drm_get_edid(struct drm_connector *connector, 
	if (connector->force == DRM_FORCE_UNSPECIFIED && !drm_probe_ddc(adapter))

		return NULL;



	edid = drm_do_get_edid(connector, drm_do_probe_ddc_edid, adapter);

	edid = _drm_do_get_edid(connector, drm_do_probe_ddc_edid, adapter, NULL);

	drm_connector_update_edid_property(connector, edid);

	return edid;

}

EXPORT_SYMBOL(drm_get_edid);



/**

 * drm_edid_read_custom - Read EDID data using given EDID block read function

 * @connector: Connector to use

 * @read_block: EDID block read function

 * @context: Private data passed to the block read function

 *

 * When the I2C adapter connected to the DDC bus is hidden behind a device that

 * exposes a different interface to read EDID blocks this function can be used

 * to get EDID data using a custom block read function.

 *

 * As in the general case the DDC bus is accessible by the kernel at the I2C

 * level, drivers must make all reasonable efforts to expose it as an I2C

 * adapter and use drm_edid_read() or drm_edid_read_ddc() instead of abusing

 * this function.

 *

 * The EDID may be overridden using debugfs override_edid or firmware EDID

 * (drm_load_edid_firmware() and drm.edid_firmware parameter), in this priority

 * order. Having either of them bypasses actual EDID reads.

 *

 * The returned pointer must be freed using drm_edid_free().

 *

 * Return: Pointer to EDID, or NULL if probe/read failed.

 */

const struct drm_edid *drm_edid_read_custom(struct drm_connector *connector,

					    read_block_fn read_block,

					    void *context)

{

	const struct drm_edid *drm_edid;

	struct edid *edid;

	size_t size = 0;



	edid = _drm_do_get_edid(connector, read_block, context, &size);

	if (!edid)

		return NULL;



	/* Sanity check for now */

	drm_WARN_ON(connector->dev, !size);



	drm_edid = _drm_edid_alloc(edid, size);

	if (!drm_edid)

		kfree(edid);



	return drm_edid;

}

EXPORT_SYMBOL(drm_edid_read_custom);



/**

 * drm_edid_read_ddc - Read EDID data using given I2C adapter

 * @connector: Connector to use

 * @adapter: I2C adapter to use for DDC

 *

 * Read EDID using the given I2C adapter.

 *

 * The EDID may be overridden using debugfs override_edid or firmware EDID

 * (drm_load_edid_firmware() and drm.edid_firmware parameter), in this priority

 * order. Having either of them bypasses actual EDID reads.

 *

 * Prefer initializing connector->ddc with drm_connector_init_with_ddc() and

 * using drm_edid_read() instead of this function.

 *

 * The returned pointer must be freed using drm_edid_free().

 *

 * Return: Pointer to EDID, or NULL if probe/read failed.

 */

const struct drm_edid *drm_edid_read_ddc(struct drm_connector *connector,

					 struct i2c_adapter *adapter)

{

	const struct drm_edid *drm_edid;



	if (connector->force == DRM_FORCE_OFF)

		return NULL;



	if (connector->force == DRM_FORCE_UNSPECIFIED && !drm_probe_ddc(adapter))

		return NULL;



	drm_edid = drm_edid_read_custom(connector, drm_do_probe_ddc_edid, adapter);



	/* Note: Do *not* call connector updates here. */



	return drm_edid;

}

EXPORT_SYMBOL(drm_edid_read_ddc);



/**

 * drm_edid_read - Read EDID data using connector's I2C adapter

 * @connector: Connector to use

 *

 * Read EDID using the connector's I2C adapter.

 *

 * The EDID may be overridden using debugfs override_edid or firmware EDID

 * (drm_load_edid_firmware() and drm.edid_firmware parameter), in this priority

 * order. Having either of them bypasses actual EDID reads.

 *

 * The returned pointer must be freed using drm_edid_free().

 *

 * Return: Pointer to EDID, or NULL if probe/read failed.

 */

const struct drm_edid *drm_edid_read(struct drm_connector *connector)

{

	if (drm_WARN_ON(connector->dev, !connector->ddc))

		return NULL;



	return drm_edid_read_ddc(connector, connector->ddc);

}

EXPORT_SYMBOL(drm_edid_read);



static u32 edid_extract_panel_id(const struct edid *edid)

{

	/*

include/drm/drm_edid.h

+9 −0
Original line number Diff line number Diff line
@@ -594,6 +594,15 @@ drm_display_mode_from_cea_vic(struct drm_device *dev, 
			      u8 video_code);



/* Interface based on struct drm_edid */

const struct drm_edid *drm_edid_alloc(const void *edid, size_t size);

const struct drm_edid *drm_edid_dup(const struct drm_edid *drm_edid);

void drm_edid_free(const struct drm_edid *drm_edid);

const struct drm_edid *drm_edid_read(struct drm_connector *connector);

const struct drm_edid *drm_edid_read_ddc(struct drm_connector *connector,

					 struct i2c_adapter *adapter);

const struct drm_edid *drm_edid_read_custom(struct drm_connector *connector,

					    int (*read_block)(void *context, u8 *buf, unsigned int block, size_t len),

					    void *context);

const u8 *drm_find_edid_extension(const struct drm_edid *drm_edid,

				  int ext_id, int *ext_index);