drm/amdgpu: Add flags for partition mode query

It's not required to take lock on all cases while querying partition
mode. Querying partition mode during KFD init process doesn't need to
take a lock. Init process after a switch will already be happening under
lock. Control the behaviour by adding flags to xcp_query_partition_mode.
Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c

@@ -1177,7 +1177,8 @@ static ssize_t amdgpu_gfx_get_current_compute_partition(struct device *dev,
 	int mode;
 	char *partition_mode;
 
-	mode = amdgpu_xcp_query_partition_mode(adev->xcp_mgr);
+	mode = amdgpu_xcp_query_partition_mode(adev->xcp_mgr,
+					       AMDGPU_XCP_FL_NONE);
 
 	switch (mode) {
 	case AMDGPU_SPX_PARTITION_MODE:

drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c

@@ -170,7 +170,7 @@ int amdgpu_xcp_switch_partition_mode(struct amdgpu_xcp_mgr *xcp_mgr, int mode)
 	return ret;
 }
 
-int amdgpu_xcp_query_partition_mode(struct amdgpu_xcp_mgr *xcp_mgr)
+int amdgpu_xcp_query_partition_mode(struct amdgpu_xcp_mgr *xcp_mgr, u32 flags)
 {
 	int mode;
 
@@ -180,7 +180,8 @@ int amdgpu_xcp_query_partition_mode(struct amdgpu_xcp_mgr *xcp_mgr)
 	if (!xcp_mgr->funcs || !xcp_mgr->funcs->query_partition_mode)
 		return xcp_mgr->mode;
 
-	mutex_lock(&xcp_mgr->xcp_lock);
+	if (!(flags & AMDGPU_XCP_FL_LOCKED))
+		mutex_lock(&xcp_mgr->xcp_lock);
 	mode = xcp_mgr->funcs->query_partition_mode(xcp_mgr);
 	if (mode != xcp_mgr->mode)
 		dev_WARN(
@@ -188,7 +189,8 @@ int amdgpu_xcp_query_partition_mode(struct amdgpu_xcp_mgr *xcp_mgr)
 			"Cached partition mode %d not matching with device mode %d",
 			xcp_mgr->mode, mode);
 
-	mutex_unlock(&xcp_mgr->xcp_lock);
+	if (!(flags & AMDGPU_XCP_FL_LOCKED))
+		mutex_unlock(&xcp_mgr->xcp_lock);
 
 	return mode;
 }

drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.h

@@ -30,6 +30,9 @@
 
 #define AMDGPU_XCP_MODE_NONE -1
 
+#define AMDGPU_XCP_FL_NONE 0
+#define AMDGPU_XCP_FL_LOCKED (1 << 0)
+
 enum AMDGPU_XCP_IP_BLOCK {
 	AMDGPU_XCP_GFXHUB,
 	AMDGPU_XCP_GFX,
@@ -99,7 +102,7 @@ int amdgpu_xcp_resume(struct amdgpu_xcp_mgr *xcp_mgr, int xcp_id);
 
 int amdgpu_xcp_mgr_init(struct amdgpu_device *adev, int init_mode,
 			int init_xcps, struct amdgpu_xcp_mgr_funcs *xcp_funcs);
-int amdgpu_xcp_query_partition_mode(struct amdgpu_xcp_mgr *xcp_mgr);
+int amdgpu_xcp_query_partition_mode(struct amdgpu_xcp_mgr *xcp_mgr, u32 flags);
 int amdgpu_xcp_switch_partition_mode(struct amdgpu_xcp_mgr *xcp_mgr, int mode);
 int amdgpu_xcp_get_partition(struct amdgpu_xcp_mgr *xcp_mgr,
 			     enum AMDGPU_XCP_IP_BLOCK ip, int instance);

drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c

@@ -1940,7 +1940,9 @@ static int gfx_v9_4_3_cp_resume(struct amdgpu_device *adev)
 {
 	int r, i, num_xcc;
 
-	if (amdgpu_xcp_query_partition_mode(adev->xcp_mgr) == AMDGPU_UNKNOWN_COMPUTE_PARTITION_MODE)
+	if (amdgpu_xcp_query_partition_mode(adev->xcp_mgr,
+					    AMDGPU_XCP_FL_NONE) ==
+	    AMDGPU_UNKNOWN_COMPUTE_PARTITION_MODE)
 		amdgpu_xcp_switch_partition_mode(adev->xcp_mgr, amdgpu_user_partt_mode);
 
 	num_xcc = NUM_XCC(adev->gfx.xcc_mask);

drivers/gpu/drm/amd/amdkfd/kfd_device.c

@@ -645,7 +645,7 @@ bool kgd2kfd_device_init(struct kfd_dev *kfd,
 	 * If the VMID range changes for GFX9.4.3, then this code MUST be
 	 * revisited.
 	 */
-	partition_mode = amdgpu_xcp_query_partition_mode(kfd->adev->xcp_mgr);
+	partition_mode = amdgpu_xcp_query_partition_mode(kfd->adev->xcp_mgr, AMDGPU_XCP_FL_LOCKED);
 	if (KFD_GC_VERSION(kfd) == IP_VERSION(9, 4, 3) &&
 	    partition_mode == AMDGPU_CPX_PARTITION_MODE &&
 	    kfd->num_nodes != 1) {