[PATCH 18/22] drm/vkms: Introduce config for connector EDID

[Louis Chauvet <louis.chauvet@bootlin.com>]

Allows configuration of EDID for each connector.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/tests/vkms_config_test.c |  2 +
 drivers/gpu/drm/vkms/vkms_config.h            | 77 +++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_connector.c         | 48 +++++++++++++++--
 3 files changed, 123 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/vkms/tests/vkms_config_test.c b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
index a89ccd75060d..d1e380da31ff 100644
--- a/drivers/gpu/drm/vkms/tests/vkms_config_test.c
+++ b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
@@ -190,6 +190,8 @@ static void vkms_config_test_default_config(struct kunit *test)
 		KUNIT_EXPECT_EQ(test,
 				vkms_config_connector_get_supported_colorspaces(connector_cfg),
 				0);
+		KUNIT_EXPECT_EQ(test, vkms_config_connector_get_edid_enabled(connector_cfg),
+				false);
 	}
 
 	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
index ec614c2d4a30..eaf76a58aab6 100644
--- a/drivers/gpu/drm/vkms/vkms_config.h
+++ b/drivers/gpu/drm/vkms/vkms_config.h
@@ -129,6 +129,8 @@ struct vkms_config_encoder {
  * @type: Store the type of connector using DRM_MODE_CONNECTOR_* values
  * @config: The vkms_config this connector belongs to
  * @status: Status (connected, disconnected...) of the connector
+ * @edid: Stores the current EDID
+ * @edid_len: Current EDID length
  * @possible_encoders: Array of encoders that can be used with this connector
  * @connector: Internal usage. This pointer should never be considered as valid.
  *             It can be used to store a temporary reference to a VKMS connector
@@ -142,6 +144,9 @@ struct vkms_config_connector {
 	int type;
 	enum drm_connector_status status;
 	u32 supported_colorspaces;
+	bool edid_enabled;
+	u8 *edid;
+	unsigned int edid_len;
 	struct xarray possible_encoders;
 
 	/* Internal usage */
@@ -265,6 +270,78 @@ vkms_config_connector_get_supported_colorspaces(struct vkms_config_connector *co
 	return connector_cfg->supported_colorspaces;
 }
 
+/**
+ * vkms_config_connector_get_edid_enabled() - Check if EDID is enabled for a connector
+ * @connector_cfg: Connector configuration to check
+ *
+ * Returns:
+ * True if EDID is enabled for this connector, false otherwise.
+ */
+static inline bool
+vkms_config_connector_get_edid_enabled(struct vkms_config_connector *connector_cfg)
+{
+	return connector_cfg->edid_enabled;
+}
+
+/**
+ * vkms_config_connector_set_edid_enabled() - Enable or disable EDID for a connector
+ * @connector_cfg: Connector configuration to modify
+ * @enabled: Whether to enable EDID for this connector
+ */
+static inline void
+vkms_config_connector_set_edid_enabled(struct vkms_config_connector *connector_cfg,
+				       bool enabled)
+{
+	connector_cfg->edid_enabled = enabled;
+}
+
+/**
+ * vkms_config_connector_get_edid() - Get the EDID data for a connector
+ * @connector_cfg: Connector configuration to get the EDID from
+ * @len: Pointer to store the length of the EDID data
+ *
+ * Returns:
+ * Pointer to the EDID data buffer, or NULL if no EDID is set.
+ * The length of the EDID data is stored in @len.
+ */
+static inline const u8 *
+vkms_config_connector_get_edid(const struct vkms_config_connector *connector_cfg, int *len)
+{
+	*len = connector_cfg->edid_len;
+	return connector_cfg->edid;
+}
+
+/**
+ * vkms_config_connector_set_edid() - Set the EDID data for a connector
+ * @connector_cfg: Connector configuration to modify
+ * @edid: Pointer to the EDID data buffer
+ * @len: Length of the EDID data
+ *
+ * If @len is 0, the EDID data will be cleared. If memory allocation fails,
+ * the existing EDID data will be preserved.
+ */
+static inline void
+vkms_config_connector_set_edid(struct vkms_config_connector *connector_cfg,
+			       const u8 *edid, unsigned int len)
+{
+	if (len) {
+		void *edid_tmp = krealloc(connector_cfg->edid, len, GFP_KERNEL);
+
+		if (edid_tmp) {
+			connector_cfg->edid = edid_tmp;
+			memcpy(connector_cfg->edid, edid, len);
+			connector_cfg->edid_len = len;
+		} else {
+			kfree(connector_cfg->edid);
+			connector_cfg->edid_len = 0;
+		}
+	} else {
+		kfree(connector_cfg->edid);
+		connector_cfg->edid = NULL;
+		connector_cfg->edid_len = len;
+	}
+}
+
 /**
  * vkms_config_get_device_name() - Return the name of the device
  * @config: Configuration to get the device name from
diff --git a/drivers/gpu/drm/vkms/vkms_connector.c b/drivers/gpu/drm/vkms/vkms_connector.c
index cc59d13c2d22..339d747e729e 100644
--- a/drivers/gpu/drm/vkms/vkms_connector.c
+++ b/drivers/gpu/drm/vkms/vkms_connector.c
@@ -42,13 +42,53 @@ static const struct drm_connector_funcs vkms_connector_funcs = {
 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 };
 
+static int vkms_connector_read_block(void *context, u8 *buf, unsigned int block, size_t len)
+{
+	struct vkms_config_connector *config = context;
+	unsigned int edid_len;
+	const u8 *edid = vkms_config_connector_get_edid(config, &edid_len);
+
+	if (block * len + len > edid_len)
+		return 1;
+	memcpy(buf, &edid[block * len], len);
+	return 0;
+}
+
 static int vkms_conn_get_modes(struct drm_connector *connector)
 {
-	int count;
+	struct vkms_connector *vkms_connector = drm_connector_to_vkms_connector(connector);
+	const struct drm_edid *drm_edid = NULL;
+	int count = 0;
+	struct vkms_config_connector *context = NULL;
+	struct drm_device *dev = connector->dev;
+	struct vkms_device *vkmsdev = drm_device_to_vkms_device(dev);
+	struct vkms_config_connector *connector_cfg;
 
-	/* Use the default modes list from DRM */
-	count = drm_add_modes_noedid(connector, XRES_MAX, YRES_MAX);
-	drm_set_preferred_mode(connector, XRES_DEF, YRES_DEF);
+	vkms_config_for_each_connector(vkmsdev->config, connector_cfg) {
+		if (connector_cfg->connector == vkms_connector)
+			context = connector_cfg;
+	}
+	if (context) {
+		if (vkms_config_connector_get_edid_enabled(context)) {
+			drm_edid = drm_edid_read_custom(connector,
+							vkms_connector_read_block, context);
+
+			/*
+			 * Unconditionally update the connector. If the EDID was read
+			 * successfully, fill in the connector information derived from the
+			 * EDID. Otherwise, if the EDID is NULL, clear the connector
+			 * information.
+			 */
+			drm_edid_connector_update(connector, drm_edid);
+
+			count = drm_edid_connector_add_modes(connector);
+
+			drm_edid_free(drm_edid);
+		} else {
+			count = drm_add_modes_noedid(connector, XRES_MAX, YRES_MAX);
+			drm_set_preferred_mode(connector, XRES_DEF, YRES_DEF);
+		}
+	}
 
 	return count;
 }

-- 
2.51.0