nouveau: handle EBUSY and EAGAIN for GSP aux errors.

The upper layer transfer functions expect EBUSY as a return
for when retries should be done.

Fix the AUX error translation, but also check for both errors
in a few places.

Fixes: eb284f4 ("drm/nouveau/dp: Honor GSP link training retry timeouts")
Cc: stable@vger.kernel.org
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241111034126.2028401-1-airlied@gmail.com

Author: airlied

drivers/gpu/drm/nouveau/nvkm/engine/disp/r535.c

@@ -992,7 +992,7 @@ r535_dp_train_target(struct nvkm_outp *outp, u8 target, bool mst, u8 link_nr, u8
 		ctrl->data = data;
 
 		ret = nvkm_gsp_rm_ctrl_push(&disp->rm.objcom, &ctrl, sizeof(*ctrl));
-		if (ret == -EAGAIN && ctrl->retryTimeMs) {
+		if ((ret == -EAGAIN || ret == -EBUSY) && ctrl->retryTimeMs) {
 			/*
 			 * Device (likely an eDP panel) isn't ready yet, wait for the time specified
 			 * by GSP before retrying again

drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c

@@ -78,7 +78,7 @@ r535_rpc_status_to_errno(uint32_t rpc_status)
 	switch (rpc_status) {
 	case 0x55: /* NV_ERR_NOT_READY */
 	case 0x66: /* NV_ERR_TIMEOUT_RETRY */
-		return -EAGAIN;
+		return -EBUSY;
 	case 0x51: /* NV_ERR_NO_MEMORY */
 		return -ENOMEM;
 	default:
@@ -601,7 +601,7 @@ r535_gsp_rpc_rm_alloc_push(struct nvkm_gsp_object *object, void *argv, u32 repc)
 
 	if (rpc->status) {
 		ret = ERR_PTR(r535_rpc_status_to_errno(rpc->status));
-		if (PTR_ERR(ret) != -EAGAIN)
+		if (PTR_ERR(ret) != -EAGAIN && PTR_ERR(ret) != -EBUSY)
 			nvkm_error(&gsp->subdev, "RM_ALLOC: 0x%x\n", rpc->status);
 	} else {
 		ret = repc ? rpc->params : NULL;
@@ -660,7 +660,7 @@ r535_gsp_rpc_rm_ctrl_push(struct nvkm_gsp_object *object, void **argv, u32 repc)
 
 	if (rpc->status) {
 		ret = r535_rpc_status_to_errno(rpc->status);
-		if (ret != -EAGAIN)
+		if (ret != -EAGAIN && ret != -EBUSY)
 			nvkm_error(&gsp->subdev, "cli:0x%08x obj:0x%08x ctrl cmd:0x%08x failed: 0x%08x\n",
 				   object->client->object.handle, object->handle, rpc->cmd, rpc->status);
 	}