accel/ivpu: Add support for VPU_JOB_FLAGS_NULL_SUBMISSION_MASK

Add test_mode = 3 that add VPU_JOB_FLAGS_NULL_SUBMISSION_MASK
flag to the job send to the VPU device. Then the VPU will process
the job but won't execute commands (except the command to signal
the fence).

This can be used to estimate job processing overhead in the host
software and VPU firmware.

Unlike the null hardware mode, the null submission mode will
still work even if UMD uses VPU fences to track job completion.
Signed-off-by: Andrzej Kacprowski <andrzej.kacprowski@linux.intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231028133415.1169975-6-stanislaw.gruszka@linux.intel.com

drivers/accel/ivpu/ivpu_drv.c

@@ -39,7 +39,7 @@ MODULE_PARM_DESC(dbg_mask, "Driver debug mask. See IVPU_DBG_* macros.");
 
 int ivpu_test_mode;
 module_param_named_unsafe(test_mode, ivpu_test_mode, int, 0644);
-MODULE_PARM_DESC(test_mode, "Test mode: 0 - normal operation, 1 - fw unit test, 2 - null hw");
+MODULE_PARM_DESC(test_mode, "Test mode: 0 - disabled , 1 - fw unit test, 2 - null hw, 3 - null submission");
 
 u8 ivpu_pll_min_ratio;
 module_param_named(pll_min_ratio, ivpu_pll_min_ratio, byte, 0644);

drivers/accel/ivpu/ivpu_drv.h

@@ -150,6 +150,7 @@ extern bool ivpu_disable_mmu_cont_pages;
 #define IVPU_TEST_MODE_DISABLED        0
 #define IVPU_TEST_MODE_FW_TEST         1
 #define IVPU_TEST_MODE_NULL_HW         2
+#define IVPU_TEST_MODE_NULL_SUBMISSION 3
 extern int ivpu_test_mode;
 
 struct ivpu_file_priv *ivpu_file_priv_get(struct ivpu_file_priv *file_priv);

drivers/accel/ivpu/ivpu_job.c

@@ -196,6 +196,8 @@ static int ivpu_cmdq_push_job(struct ivpu_cmdq *cmdq, struct ivpu_job *job)
 	entry->batch_buf_addr = job->cmd_buf_vpu_addr;
 	entry->job_id = job->job_id;
 	entry->flags = 0;
+	if (unlikely(ivpu_test_mode == IVPU_TEST_MODE_NULL_SUBMISSION))
+		entry->flags = VPU_JOB_FLAGS_NULL_SUBMISSION_MASK;
 	wmb(); /* Ensure that tail is updated after filling entry */
 	header->tail = next_entry;
 	wmb(); /* Flush WC buffer for jobq header */