[PATCH 3/4] drm/amdkfd: Fix bugs regarding CP queue doorbell mask on SOC15

["Zhao, Yong" <Yong.Zhao-5C7GfCeVMHo@public.gmane.org>]

Reserved doorbells for SDMA IH and VCN were not properly masked out
when allocating doorbells for CP user queues. This patch fixed that.

Change-Id: I670adfc3fd7725d2ed0bd9665cb7f69f8b9023c2
Signed-off-by: Yong Zhao <Yong.Zhao@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c      | 16 ++++++++++++----
 drivers/gpu/drm/amd/amdkfd/kfd_priv.h           | 11 +++++++++++
 drivers/gpu/drm/amd/amdkfd/kfd_process.c        | 14 +++++++++-----
 drivers/gpu/drm/amd/include/kgd_kfd_interface.h | 15 ++++++---------
 4 files changed, 38 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
index e957e42c539a..30e2b371578e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
@@ -196,11 +196,19 @@ void amdgpu_amdkfd_device_init(struct amdgpu_device *adev)
 			gpu_resources.sdma_doorbell[1][i+1] =
 				adev->doorbell_index.sdma_engine[1] + 0x200 + (i >> 1);
 		}
-		/* Doorbells 0x0e0-0ff and 0x2e0-2ff are reserved for
-		 * SDMA, IH and VCN. So don't use them for the CP.
+
+		/* Since SOC15, BIF starts to statically use the
+		 * lower 12 bits of doorbell addresses for routing
+		 * based on settings in registers like
+		 * SDMA0_DOORBELL_RANGE etc..
+		 * In order to route a doorbell to CP engine, the lower
+		 * 12 bits of its address has to be outside the range
+		 * set for SDMA, VCN, and IH blocks.
 		 */
-		gpu_resources.reserved_doorbell_mask = 0x1e0;
-		gpu_resources.reserved_doorbell_val  = 0x0e0;
+		gpu_resources.non_cp_doorbells_start =
+				adev->doorbell_index.first_non_cp;
+		gpu_resources.non_cp_doorbells_end =
+				adev->doorbell_index.last_non_cp;
 
 		kgd2kfd_device_init(adev->kfd.dev, &gpu_resources);
 	}
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
index e5ebcca7f031..0eeee3c6d6dc 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
@@ -103,6 +103,17 @@
 
 #define KFD_KERNEL_QUEUE_SIZE 2048
 
+/*
+ * 512 = 0x200
+ * The doorbell index distance between SDMA RLC (2*i) and (2*i+1) in the
+ * same SDMA engine on SOC15, which has 8-byte doorbells for SDMA.
+ * 512 8-byte doorbell distance (i.e. one page away) ensures that SDMA RLC
+ * (2*i+1) doorbells (in terms of the lower 12 bit address) lie exactly in
+ * the OFFSET and SIZE set in registers like BIF_SDMA0_DOORBELL_RANGE.
+ */
+#define KFD_QUEUE_DOORBELL_MIRROR_OFFSET 512
+
+
 /*
  * Kernel module parameter to specify maximum number of supported queues per
  * device
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
index 80b36e860a0a..4bdae78bab8e 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
@@ -607,13 +607,17 @@ static int init_doorbell_bitmap(struct qcm_process_device *qpd,
 	if (!qpd->doorbell_bitmap)
 		return -ENOMEM;
 
-	/* Mask out any reserved doorbells */
-	for (i = 0; i < KFD_MAX_NUM_OF_QUEUES_PER_PROCESS; i++)
-		if ((dev->shared_resources.reserved_doorbell_mask & i) ==
-		    dev->shared_resources.reserved_doorbell_val) {
+	/* Mask out doorbells reserved for SDMA, IH, and VCN on SOC15. */
+	for (i = 0; i < KFD_MAX_NUM_OF_QUEUES_PER_PROCESS / 2; i++) {
+		if (i >= dev->shared_resources.non_cp_doorbells_start
+			&& i <= dev->shared_resources.non_cp_doorbells_end) {
 			set_bit(i, qpd->doorbell_bitmap);
-			pr_debug("reserved doorbell 0x%03x\n", i);
+			set_bit(i + KFD_QUEUE_DOORBELL_MIRROR_OFFSET,
+				qpd->doorbell_bitmap);
+			pr_debug("reserved doorbell 0x%03x and 0x%03x\n", i,
+				i + KFD_QUEUE_DOORBELL_MIRROR_OFFSET);
 		}
+	}
 
 	return 0;
 }
diff --git a/drivers/gpu/drm/amd/include/kgd_kfd_interface.h b/drivers/gpu/drm/amd/include/kgd_kfd_interface.h
index 83d960110d23..0b6b34f4e5a1 100644
--- a/drivers/gpu/drm/amd/include/kgd_kfd_interface.h
+++ b/drivers/gpu/drm/amd/include/kgd_kfd_interface.h
@@ -140,17 +140,14 @@ struct kgd2kfd_shared_resources {
 	/* Doorbell assignments (SOC15 and later chips only). Only
 	 * specific doorbells are routed to each SDMA engine. Others
 	 * are routed to IH and VCN. They are not usable by the CP.
-	 *
-	 * Any doorbell number D that satisfies the following condition
-	 * is reserved: (D & reserved_doorbell_mask) == reserved_doorbell_val
-	 *
-	 * KFD currently uses 1024 (= 0x3ff) doorbells per process. If
-	 * doorbells 0x0e0-0x0ff and 0x2e0-0x2ff are reserved, that means
-	 * mask would be set to 0x1e0 and val set to 0x0e0.
 	 */
 	unsigned int sdma_doorbell[2][8];
-	unsigned int reserved_doorbell_mask;
-	unsigned int reserved_doorbell_val;
+
+	/* From SOC15 onward, the doorbell index range not usable for CP
+	 * queues.
+	 */
+	uint32_t non_cp_doorbells_start;
+	uint32_t non_cp_doorbells_end;
 
 	/* Base address of doorbell aperture. */
 	phys_addr_t doorbell_physical_address;
-- 
2.17.1

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