[PATCH 07/16] drm/amdgpu: add helper to create doorbell pages

[Shashank Sharma]

From: Shashank Sharma <contactshashanksharma at gmail.com>

This patch adds helper functions to create and free doorbell
pages for kernel objects.

Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: Christian Koenig <christian.koenig at amd.com>
Signed-off-by: Shashank Sharma <shashank.sharma at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h  | 41 ++++++++++++++++
 .../gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c  | 49 +++++++++++++++++++
 2 files changed, 90 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h
index f9c3b77bf65d..6581b78fe438 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h
@@ -27,6 +27,24 @@
 /*
  * GPU doorbell structures, functions & helpers
  */
+
+/* Structure to hold doorbell pages from PCI doorbell BAR */
+struct amdgpu_doorbell_obj {
+	struct amdgpu_bo *bo;
+	uint64_t gpu_addr;
+	uint32_t *cpu_addr;
+	uint32_t size;
+
+	/* First index in this object */
+	uint32_t start;
+
+	/* Last index in this object */
+	uint32_t end;
+
+	/* bitmap for dynamic doorbell allocation from this object */
+	unsigned long *doorbell_bitmap;
+};
+
 struct amdgpu_doorbell {
 	/* doorbell mmio */
 	resource_size_t		base;
@@ -328,6 +346,29 @@ int amdgpu_device_doorbell_init(struct amdgpu_device *adev);
  */
 void amdgpu_device_doorbell_fini(struct amdgpu_device *adev);
 
+/**
+ * amdgpu_doorbell_free_page - Free a doorbell page
+ *
+ * @adev: amdgpu_device pointer
+ *
+ * @db_age: previously allocated doobell page details
+ *
+ */
+void amdgpu_doorbell_free_page(struct amdgpu_device *adev,
+				struct amdgpu_doorbell_obj *db_obj);
+
+/**
+ * amdgpu_doorbell_alloc_page - create a page from doorbell pool
+ *
+ * @adev: amdgpu_device pointer
+ *
+ * @db_age: doobell page structure to fill details with
+ *
+ * returns 0 on success, else error number
+ */
+int amdgpu_doorbell_alloc_page(struct amdgpu_device *adev,
+				struct amdgpu_doorbell_obj *db_obj);
+
 #define RDOORBELL32(index) amdgpu_mm_rdoorbell(adev, (index))
 #define WDOORBELL32(index, v) amdgpu_mm_wdoorbell(adev, (index), (v))
 #define RDOORBELL64(index) amdgpu_mm_rdoorbell64(adev, (index))
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
index 1aea92363fd3..8be15b82b545 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
@@ -111,6 +111,55 @@ void amdgpu_mm_wdoorbell64(struct amdgpu_device *adev, u32 index, u64 v)
 	}
 }
 
+/**
+ * amdgpu_doorbell_free_page - Free a doorbell page
+ *
+ * @adev: amdgpu_device pointer
+ *
+ * @db_age: previously allocated doobell page details
+ *
+ */
+void amdgpu_doorbell_free_page(struct amdgpu_device *adev,
+					struct amdgpu_doorbell_obj *db_obj)
+{
+	amdgpu_bo_free_kernel(&db_obj->bo,
+			      &db_obj->gpu_addr,
+			      (void **)&db_obj->cpu_addr);
+
+}
+
+/**
+ * amdgpu_doorbell_alloc_page - create a page from doorbell pool
+ *
+ * @adev: amdgpu_device pointer
+ *
+ * @db_age: doobell page structure to fill details with
+ *
+ * returns 0 on success, else error number
+ */
+int amdgpu_doorbell_alloc_page(struct amdgpu_device *adev,
+				struct amdgpu_doorbell_obj *db_obj)
+{
+	int r;
+
+	db_obj->size = ALIGN(db_obj->size, PAGE_SIZE);
+
+	r = amdgpu_bo_create_kernel(adev,
+				    db_obj->size,
+				    PAGE_SIZE,
+				    AMDGPU_GEM_DOMAIN_DOORBELL,
+				    &db_obj->bo,
+				    &db_obj->gpu_addr,
+				    (void **)&db_obj->cpu_addr);
+
+	if (r) {
+		DRM_ERROR("Failed to create doorbell BO, err=%d\n", r);
+		return r;
+	}
+
+	return 0;
+}
+
 /*
  * GPU doorbell aperture helpers function.
  */
-- 
2.40.0