[PATCH v3 06/12] drm/amdgpu: create kernel doorbell pages

Shashank Sharma shashank.sharma at amd.com
Tue Jun 20 17:16:02 UTC 2023 

This patch:
- creates a doorbell page for graphics driver usages.
- adds a few new varlables in adev->doorbell structure to
  keep track of kernel's doorbell-bo.
- removes the adev->doorbell.ptr variable, replaces it with
  kernel-doorbell-bo's cpu address.

V2: - Create doorbell BO directly, no wrappe functions (Alex)
    - no additional doorbell structure (Alex, Christian)
    - Use doorbell_cpu_ptr, remove ioremap (Christian, Alex)
    - Allocate one extra page of doorbells for MES (Alex)

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  |  8 ++-
 .../gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c  | 56 ++++++++++++++-----
 drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h       |  3 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c       |  7 +++
 4 files changed, 60 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h
index 783e2b8b086c..002899edb9d7 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h
@@ -31,10 +31,15 @@ struct amdgpu_doorbell {
 	/* doorbell mmio */
 	resource_size_t		base;
 	resource_size_t		size;
-	u32 __iomem		*ptr;
 
 	/* Number of doorbells reserved for amdgpu kernel driver */
 	u32 num_kernel_doorbells;
+
+	/* Kernel doorbells */
+	struct amdgpu_bo *kernel_doorbells;
+
+	/* For CPU access of doorbells */
+	uint32_t *cpu_addr;
 };
 
 /* Reserved doorbells for amdgpu (including multimedia).
@@ -311,6 +316,7 @@ void amdgpu_mm_wdoorbell64(struct amdgpu_device *adev, u32 index, u64 v);
  */
 int amdgpu_doorbell_init(struct amdgpu_device *adev);
 void amdgpu_doorbell_fini(struct amdgpu_device *adev);
+int amdgpu_doorbell_create_kernel_doorbells(struct amdgpu_device *adev);
 
 #define RDOORBELL32(index) amdgpu_mm_rdoorbell(adev, (index))
 #define WDOORBELL32(index, v) amdgpu_mm_wdoorbell(adev, (index), (v))
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
index eb113e38f5e9..118f4bed32fd 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
@@ -39,7 +39,7 @@ u32 amdgpu_mm_rdoorbell(struct amdgpu_device *adev, u32 index)
 		return 0;
 
 	if (index < adev->doorbell.num_kernel_doorbells)
-		return readl(adev->doorbell.ptr + index);
+		return readl(adev->doorbell.cpu_addr + index);
 
 	DRM_ERROR("reading beyond doorbell aperture: 0x%08x!\n", index);
 	return 0;
@@ -61,7 +61,7 @@ void amdgpu_mm_wdoorbell(struct amdgpu_device *adev, u32 index, u32 v)
 		return;
 
 	if (index < adev->doorbell.num_kernel_doorbells)
-		writel(v, adev->doorbell.ptr + index);
+		writel(v, adev->doorbell.cpu_addr + index);
 	else
 		DRM_ERROR("writing beyond doorbell aperture: 0x%08x!\n", index);
 }
@@ -81,7 +81,7 @@ u64 amdgpu_mm_rdoorbell64(struct amdgpu_device *adev, u32 index)
 		return 0;
 
 	if (index < adev->doorbell.num_kernel_doorbells)
-		return atomic64_read((atomic64_t *)(adev->doorbell.ptr + index));
+		return atomic64_read((atomic64_t *)(adev->doorbell.cpu_addr + index));
 
 	DRM_ERROR("reading beyond doorbell aperture: 0x%08x!\n", index);
 	return 0;
@@ -103,11 +103,47 @@ void amdgpu_mm_wdoorbell64(struct amdgpu_device *adev, u32 index, u64 v)
 		return;
 
 	if (index < adev->doorbell.num_kernel_doorbells)
-		atomic64_set((atomic64_t *)(adev->doorbell.ptr + index), v);
+		atomic64_set((atomic64_t *)(adev->doorbell.cpu_addr + index), v);
 	else
 		DRM_ERROR("writing beyond doorbell aperture: 0x%08x!\n", index);
 }
 
+/**
+ * amdgpu_doorbell_create_kernel_doorbells - Create kernel doorbells for graphics
+ *
+ * @adev: amdgpu_device pointer
+ *
+ * Creates doorbells for graphics driver usages.
+ * returns 0 on success, error otherwise.
+ */
+int amdgpu_doorbell_create_kernel_doorbells(struct amdgpu_device *adev)
+{
+	int r;
+	int size;
+
+	/* Reserve first num_kernel_doorbells (page-aligned) for kernel ops */
+	size = ALIGN(adev->doorbell.num_kernel_doorbells * sizeof(u32), PAGE_SIZE);
+
+	/* Allocate an extra page for MES kernel usages (ring test) */
+	adev->mes.db_start_dw_offset = size / sizeof(u32);
+	size += PAGE_SIZE;
+
+	r = amdgpu_bo_create_kernel(adev,
+				    size,
+				    PAGE_SIZE,
+				    AMDGPU_GEM_DOMAIN_DOORBELL,
+				    &adev->doorbell.kernel_doorbells,
+				    NULL,
+				    (void **)&adev->doorbell.cpu_addr);
+	if (r) {
+		DRM_ERROR("Failed to allocate kernel doorbells, err=%d\n", r);
+		return r;
+	}
+
+	adev->doorbell.num_kernel_doorbells = size / sizeof(u32);
+	return 0;
+}
+
 /*
  * GPU doorbell aperture helpers function.
  */
@@ -127,7 +163,6 @@ int amdgpu_doorbell_init(struct amdgpu_device *adev)
 		adev->doorbell.base = 0;
 		adev->doorbell.size = 0;
 		adev->doorbell.num_kernel_doorbells = 0;
-		adev->doorbell.ptr = NULL;
 		return 0;
 	}
 
@@ -156,12 +191,6 @@ int amdgpu_doorbell_init(struct amdgpu_device *adev)
 	if (adev->asic_type >= CHIP_VEGA10)
 		adev->doorbell.num_kernel_doorbells += 0x400;
 
-	adev->doorbell.ptr = ioremap(adev->doorbell.base,
-				     adev->doorbell.num_kernel_doorbells *
-				     sizeof(u32));
-	if (adev->doorbell.ptr == NULL)
-		return -ENOMEM;
-
 	return 0;
 }
 
@@ -174,6 +203,7 @@ int amdgpu_doorbell_init(struct amdgpu_device *adev)
  */
 void amdgpu_doorbell_fini(struct amdgpu_device *adev)
 {
-	iounmap(adev->doorbell.ptr);
-	adev->doorbell.ptr = NULL;
+	amdgpu_bo_free_kernel(&adev->doorbell.kernel_doorbells,
+			      NULL,
+			      (void **)&adev->doorbell.cpu_addr);
 }
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h
index 547ec35691fa..a403418d5eac 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h
@@ -128,6 +128,9 @@ struct amdgpu_mes {
 	int                             (*kiq_hw_init)(struct amdgpu_device *adev);
 	int                             (*kiq_hw_fini)(struct amdgpu_device *adev);
 
+	/* MES doorbells */
+	uint32_t			db_start_dw_offset;
+
 	/* ip specific functions */
 	const struct amdgpu_mes_funcs   *funcs;
 };
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 6d1587bbda52..c48e97646541 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1854,6 +1854,13 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
 		return r;
 	}
 
+	/* Create a boorbell page for kernel usages */
+	r = amdgpu_doorbell_create_kernel_doorbells(adev);
+	if (r) {
+		DRM_ERROR("Failed to initialize kernel doorbells.\n");
+		return r;
+	}
+
 	/* Initialize preemptible memory pool */
 	r = amdgpu_preempt_mgr_init(adev);
 	if (r) {
-- 
2.40.1

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