[PATCH] drm/amdkfd: Add rec SDMA engines support with limited XGMI

[Shane Xiao]

This patch adds recommended SDMA engines with limited XGMI SDMA engines.
It will help improve overall performance for device to device copies
with this optimization.

Signed-off-by: Shane Xiao <shane.xiao at amd.com>
Suggested-by: Jonathan Kim <jonathan.kim at amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_topology.c | 42 ++++++++++++++---------
 1 file changed, 26 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_topology.c b/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
index 9bbee484d57c..3835b5d96355 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
@@ -1267,33 +1267,43 @@ static void kfd_set_recommended_sdma_engines(struct kfd_topology_device *to_dev,
 {
 	struct kfd_node *gpu = outbound_link->gpu;
 	struct amdgpu_device *adev = gpu->adev;
-	int num_xgmi_nodes = adev->gmc.xgmi.num_physical_nodes;
+	unsigned int num_xgmi_nodes = adev->gmc.xgmi.num_physical_nodes;
+	unsigned int num_xgmi_sdma_engines = kfd_get_num_xgmi_sdma_engines(gpu);
+	unsigned int num_sdma_engines = kfd_get_num_sdma_engines(gpu);
+	unsigned int sdma_eng_id_mask = (1 << num_sdma_engines) - 1;
+	unsigned int xgmi_sdma_eng_id_mask =
+			((1 << num_xgmi_sdma_engines) - 1) << num_sdma_engines;
+
 	bool support_rec_eng = !amdgpu_sriov_vf(adev) && to_dev->gpu &&
 		adev->aid_mask && num_xgmi_nodes && gpu->kfd->num_nodes == 1 &&
-		kfd_get_num_xgmi_sdma_engines(gpu) >= 14 &&
-		(!(adev->flags & AMD_IS_APU) && num_xgmi_nodes == 8);
+		num_xgmi_sdma_engines >= 6 && (!(adev->flags & AMD_IS_APU) &&
+		num_xgmi_nodes == 8);
 
 	if (support_rec_eng) {
 		int src_socket_id = adev->gmc.xgmi.physical_node_id;
 		int dst_socket_id = to_dev->gpu->adev->gmc.xgmi.physical_node_id;
+		unsigned int reshift = num_xgmi_sdma_engines == 6 ? 1 : 0;
 
 		outbound_link->rec_sdma_eng_id_mask =
-			1 << rec_sdma_eng_map[src_socket_id][dst_socket_id];
+				1 << (rec_sdma_eng_map[src_socket_id][dst_socket_id] >> reshift);
 		inbound_link->rec_sdma_eng_id_mask =
-			1 << rec_sdma_eng_map[dst_socket_id][src_socket_id];
-	} else {
-		int num_sdma_eng = kfd_get_num_sdma_engines(gpu);
-		int i, eng_offset = 0;
+				1 << (rec_sdma_eng_map[dst_socket_id][src_socket_id] >> reshift);
 
-		if (outbound_link->iolink_type == CRAT_IOLINK_TYPE_XGMI &&
-		    kfd_get_num_xgmi_sdma_engines(gpu) && to_dev->gpu) {
-			eng_offset = num_sdma_eng;
-			num_sdma_eng = kfd_get_num_xgmi_sdma_engines(gpu);
+		/* If recommended engine is out of range, need to reset the mask */
+		if (outbound_link->rec_sdma_eng_id_mask & sdma_eng_id_mask) {
+			outbound_link->rec_sdma_eng_id_mask = xgmi_sdma_eng_id_mask;
 		}
-
-		for (i = 0; i < num_sdma_eng; i++) {
-			outbound_link->rec_sdma_eng_id_mask |= (1 << (i + eng_offset));
-			inbound_link->rec_sdma_eng_id_mask |= (1 << (i + eng_offset));
+		if (inbound_link->rec_sdma_eng_id_mask & sdma_eng_id_mask) {
+			inbound_link->rec_sdma_eng_id_mask = xgmi_sdma_eng_id_mask;
+		}
+	} else {
+		if (outbound_link->iolink_type == CRAT_IOLINK_TYPE_XGMI &&
+		    num_xgmi_sdma_engines && to_dev->gpu) {
+			outbound_link->rec_sdma_eng_id_mask = xgmi_sdma_eng_id_mask;
+			inbound_link->rec_sdma_eng_id_mask = xgmi_sdma_eng_id_mask;
+		} else {
+			outbound_link->rec_sdma_eng_id_mask = sdma_eng_id_mask;
+			inbound_link->rec_sdma_eng_id_mask = sdma_eng_id_mask;
 		}
 	}
 }
-- 
2.25.1