[Intel-gfx] [PATCH v6 07/14] drm/i915: Add functions to allocate / release gem obj for GuC

[yu.dai at intel.com]

From: Alex Dai <yu.dai at intel.com>

All gem objects used by GuC are pinned to ggtt space out of range
[0, WOPCM size]. In GuC address space mapping, [0, WPOCM size] is
used internally for its Boot ROM, SRAM etc. Currently this WPOCM
size is 512K. This is done by using of PIN_OFFSET_BIAS.

Issue: VIZ-4884
Signed-off-by: Alex Dai <yu.dai at intel.com>
---
 drivers/gpu/drm/i915/intel_guc.h        |  3 ++
 drivers/gpu/drm/i915/intel_guc_loader.c | 55 +++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_guc.h b/drivers/gpu/drm/i915/intel_guc.h
index c6886d1..3082a3e 100644
--- a/drivers/gpu/drm/i915/intel_guc.h
+++ b/drivers/gpu/drm/i915/intel_guc.h
@@ -102,5 +102,8 @@ struct intel_guc {
 extern int intel_guc_ucode_load(struct drm_device *dev, bool wait);
 extern void intel_guc_ucode_fini(struct drm_device *dev);
 extern void intel_guc_ucode_init(struct drm_device *dev);
+struct drm_i915_gem_object *
+intel_guc_allocate_gem_obj(struct drm_device *dev, u32 size);
+void intel_guc_release_gem_obj(struct drm_i915_gem_object *obj);
 
 #endif
diff --git a/drivers/gpu/drm/i915/intel_guc_loader.c b/drivers/gpu/drm/i915/intel_guc_loader.c
index 0f13620..49f3730 100644
--- a/drivers/gpu/drm/i915/intel_guc_loader.c
+++ b/drivers/gpu/drm/i915/intel_guc_loader.c
@@ -45,6 +45,12 @@
  * The firmware installation package will install (symbolic link) proper version
  * of firmware.
  *
+ * GuC address space:
+ * GuC does not allow any gfx GGTT address that falls into range [0, WOPCM_TOP),
+ * which is reserved for Boot ROM, SRAM and WOPCM. Currently this top address is
+ * 512K. In order to exclude 0-512K address space from GGTT, all gfx objects
+ * used by GuC is pinned with PIN_OFFSET_BIAS along with size of WOPCM.
+ *
  */
 
 #define I915_SKL_GUC_UCODE "i915/skl_guc_ver1.bin"
@@ -52,6 +58,55 @@ MODULE_FIRMWARE(I915_SKL_GUC_UCODE);
 #define I915_BXT_GUC_UCODE "i915/bxt_guc_ver1.bin"
 MODULE_FIRMWARE(I915_BXT_GUC_UCODE);
 
+/**
+ * intel_guc_allocate_gem_obj() - Allocate gem object for GuC usage
+ * @dev:	drm device
+ * @size:	size of object
+ *
+ * This is a wrapper to create a gem obj. In order to use it inside GuC, the
+ * object needs to be pinned lifetime. Also we must pin it to gtt space other
+ * than [0, GUC_WOPCM_SIZE] because this range is reserved inside GuC.
+ *
+ * Return:	A drm_i915_gem_object if successful, otherwise NULL.
+ */
+struct drm_i915_gem_object *
+intel_guc_allocate_gem_obj(struct drm_device *dev, u32 size)
+{
+	struct drm_i915_gem_object *obj;
+
+	obj = i915_gem_alloc_object(dev, size);
+	if (!obj)
+		return NULL;
+
+	if (i915_gem_object_get_pages(obj)) {
+		drm_gem_object_unreference(&obj->base);
+		return NULL;
+	}
+
+	if (i915_gem_obj_ggtt_pin(obj, PAGE_SIZE,
+			PIN_OFFSET_BIAS | GUC_WOPCM_SIZE_VALUE)) {
+		drm_gem_object_unreference(&obj->base);
+		return NULL;
+	}
+
+	return obj;
+}
+
+/**
+ * intel_guc_release_gem_obj() - Release gem object allocated for GuC usage
+ * @obj:	gem obj to be released
+  */
+void intel_guc_release_gem_obj(struct drm_i915_gem_object *obj)
+{
+	if (!obj)
+		return;
+
+	if (i915_gem_obj_is_pinned(obj))
+		i915_gem_object_ggtt_unpin(obj);
+
+	drm_gem_object_unreference(&obj->base);
+}
+
 /* Read GuC status register (GUC_STATUS)
  * Return true if get a success code from normal boot or RC6 boot
  */
-- 
1.9.1