1 files changed, 65 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 800d13bd9e6a..73ceb36c790e 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -404,6 +404,70 @@ parse_driver_features(struct drm_i915_private *dev_priv,
                 dev_priv->render_reclock_avail = true;
 }
 
+static void
+parse_device_mapping(struct drm_i915_private *dev_priv,
+                       struct bdb_header *bdb)
+{
+        struct bdb_general_definitions *p_defs;
+        struct child_device_config *p_child, *child_dev_ptr;
+        int i, child_device_num, count;
+        u16     block_size;
+
+        p_defs = find_section(bdb, BDB_GENERAL_DEFINITIONS);
+        if (!p_defs) {
+                DRM_DEBUG_KMS("No general definition block is found\n");
+                return;
+        }
+        /* judge whether the size of child device meets the requirements.
+         * If the child device size obtained from general definition block
+         * is different with sizeof(struct child_device_config), skip the
+         * parsing of sdvo device info
+         */
+        if (p_defs->child_dev_size != sizeof(*p_child)) {
+                /* different child dev size . Ignore it */
+                DRM_DEBUG_KMS("different child size is found. Invalid.\n");
+                return;
+        }
+        /* get the block size of general definitions */
+        block_size = get_blocksize(p_defs);
+        /* get the number of child device */
+        child_device_num = (block_size - sizeof(*p_defs)) /
+                                sizeof(*p_child);
+        count = 0;
+        /* get the number of child device that is present */
+        for (i = 0; i < child_device_num; i++) {
+                p_child = &(p_defs->devices[i]);
+                if (!p_child->device_type) {
+                        /* skip the device block if device type is invalid */
+                        continue;
+                }
+                count++;
+        }
+        if (!count) {
+                DRM_DEBUG_KMS("no child dev is parsed from VBT \n");
+                return;
+        }
+        dev_priv->child_dev = kzalloc(sizeof(*p_child) * count, GFP_KERNEL);
+        if (!dev_priv->child_dev) {
+                DRM_DEBUG_KMS("No memory space for child device\n");
+                return;
+        }
+
+        dev_priv->child_dev_num = count;
+        count = 0;
+        for (i = 0; i < child_device_num; i++) {
+                p_child = &(p_defs->devices[i]);
+                if (!p_child->device_type) {
+                        /* skip the device block if device type is invalid */
+                        continue;
+                }
+                child_dev_ptr = dev_priv->child_dev + count;
+                count++;
+                memcpy((void *)child_dev_ptr, (void *)p_child,
+                                        sizeof(*p_child));
+        }
+        return;
+}
 /**
  * intel_init_bios - initialize VBIOS settings & find VBT
  * @dev: DRM device
@@ -455,6 +519,7 @@ intel_init_bios(struct drm_device *dev)
         parse_lfp_panel_data(dev_priv, bdb);
         parse_sdvo_panel_data(dev_priv, bdb);
         parse_sdvo_device_mapping(dev_priv, bdb);
+        parse_device_mapping(dev_priv, bdb);
         parse_driver_features(dev_priv, bdb);
 
         pci_unmap_rom(pdev, bios);