Re: [PATCH v9 16/26] drm/xe/guc: Update handling of xe_force_wake_get return

["Nilawar, Badal" <badal.nilawar@intel.com>]

On 14-10-2024 13:25, Himal Prasad Ghimiray wrote:
> xe_force_wake_get() now returns the reference count-incremented domain
> mask. If it fails for individual domains, the return value will always
> be 0. However, for XE_FORCEWAKE_ALL, it may return a non-zero value even
> in the event of failure. Use helper xe_force_wake_ref_has_domain to
> verify all domains are initialized or not. Update the return handling of
> xe_force_wake_get() to reflect this behavior, and ensure that the return
> value is passed as input to xe_force_wake_put().
> 
> v3
> - return xe_wakeref_t instead of int in xe_force_wake_get()
> - xe_force_wake_put() error doesn't need to be checked. It internally
> WARNS on domain ack failure.
> 
> v5
> - return unsigned int from xe_force_wake_get()
> - Remove redundant xe_gt_WARN_ON
> 
> v6
> - use helper xe_force_wake_ref_has_domain()
> 
> v7
> - Fix commit message
> 
> v9
> - Rebase
> 
> Cc: Matthew Brost <matthew.brost@intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Lucas De Marchi <lucas.demarchi@intel.com>
> Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
> ---
>   drivers/gpu/drm/xe/xe_guc.c        | 13 ++++----
>   drivers/gpu/drm/xe/xe_guc_log.c    |  9 +++---
>   drivers/gpu/drm/xe/xe_guc_pc.c     | 50 ++++++++++++++++++------------
>   drivers/gpu/drm/xe/xe_guc_submit.c |  6 ++--
>   4 files changed, 47 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
> index 8570b1218287..76437d42b8a1 100644
> --- a/drivers/gpu/drm/xe/xe_guc.c
> +++ b/drivers/gpu/drm/xe/xe_guc.c
> @@ -248,10 +248,11 @@ static void guc_fini_hw(void *arg)
>   {
>   	struct xe_guc *guc = arg;
>   	struct xe_gt *gt = guc_to_gt(guc);
> +	unsigned int fw_ref;
>   
> -	xe_gt_WARN_ON(gt, xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL));
> +	fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL);
>   	xe_uc_fini_hw(&guc_to_gt(guc)->uc);
> -	xe_force_wake_put(gt_to_fw(gt), XE_FORCEWAKE_ALL);
> +	xe_force_wake_put(gt_to_fw(gt), fw_ref);
>   }
>   
>   /**
> @@ -1155,14 +1156,14 @@ int xe_guc_start(struct xe_guc *guc)
>   void xe_guc_print_info(struct xe_guc *guc, struct drm_printer *p)
>   {
>   	struct xe_gt *gt = guc_to_gt(guc);
> +	unsigned int fw_ref;
>   	u32 status;
> -	int err;
>   	int i;
>   
>   	xe_uc_fw_print(&guc->fw, p);
>   
> -	err = xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
> -	if (err)
> +	fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
> +	if (!fw_ref)
>   		return;
>   
>   	status = xe_mmio_read32(&gt->mmio, GUC_STATUS);
> @@ -1183,7 +1184,7 @@ void xe_guc_print_info(struct xe_guc *guc, struct drm_printer *p)
>   			   i, xe_mmio_read32(&gt->mmio, SOFT_SCRATCH(i)));
>   	}
>   
> -	xe_force_wake_put(gt_to_fw(gt), XE_FW_GT);
> +	xe_force_wake_put(gt_to_fw(gt), fw_ref);
>   
>   	xe_guc_ct_print(&guc->ct, p);
>   	xe_guc_submit_print(guc, p);
> diff --git a/drivers/gpu/drm/xe/xe_guc_log.c b/drivers/gpu/drm/xe/xe_guc_log.c
> index cc70f448d879..fead96216243 100644
> --- a/drivers/gpu/drm/xe/xe_guc_log.c
> +++ b/drivers/gpu/drm/xe/xe_guc_log.c
> @@ -145,8 +145,9 @@ struct xe_guc_log_snapshot *xe_guc_log_snapshot_capture(struct xe_guc_log *log,
>   	struct xe_device *xe = log_to_xe(log);
>   	struct xe_guc *guc = log_to_guc(log);
>   	struct xe_gt *gt = log_to_gt(log);
> +	unsigned int fw_ref;
>   	size_t remain;
> -	int i, err;
> +	int i;
>   
>   	if (!log->bo) {
>   		xe_gt_err(gt, "GuC log buffer not allocated\n");
> @@ -168,12 +169,12 @@ struct xe_guc_log_snapshot *xe_guc_log_snapshot_capture(struct xe_guc_log *log,
>   		remain -= size;
>   	}
>   
> -	err = xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
> -	if (err) {
> +	fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
> +	if (!fw_ref) {
>   		snapshot->stamp = ~0;
>   	} else {
>   		snapshot->stamp = xe_mmio_read32(&gt->mmio, GUC_PMTIMESTAMP);
> -		xe_force_wake_put(gt_to_fw(gt), XE_FW_GT);
> +		xe_force_wake_put(gt_to_fw(gt), fw_ref);
>   	}
>   	snapshot->ktime = ktime_get_boottime_ns();
>   	snapshot->level = log->level;
> diff --git a/drivers/gpu/drm/xe/xe_guc_pc.c b/drivers/gpu/drm/xe/xe_guc_pc.c
> index 2b654f820ae2..e8b9faeaef64 100644
> --- a/drivers/gpu/drm/xe/xe_guc_pc.c
> +++ b/drivers/gpu/drm/xe/xe_guc_pc.c
> @@ -415,22 +415,24 @@ u32 xe_guc_pc_get_act_freq(struct xe_guc_pc *pc)
>   int xe_guc_pc_get_cur_freq(struct xe_guc_pc *pc, u32 *freq)
>   {
>   	struct xe_gt *gt = pc_to_gt(pc);
> -	int ret;
> +	unsigned int fw_ref;
>   
>   	/*
>   	 * GuC SLPC plays with cur freq request when GuCRC is enabled
>   	 * Block RC6 for a more reliable read.
>   	 */
> -	ret = xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL);
> -	if (ret)
> -		return ret;
> +	fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL);
> +	if (!xe_force_wake_ref_has_domain(fw_ref, XE_FORCEWAKE_ALL)) {
> +		xe_force_wake_put(gt_to_fw(gt), fw_ref);
> +		return -ETIMEDOUT;
> +	}
>   
>   	*freq = xe_mmio_read32(&gt->mmio, RPNSWREQ);
>   
>   	*freq = REG_FIELD_GET(REQ_RATIO_MASK, *freq);
>   	*freq = decode_freq(*freq);
>   
> -	XE_WARN_ON(xe_force_wake_put(gt_to_fw(gt), XE_FORCEWAKE_ALL));
> +	xe_force_wake_put(gt_to_fw(gt), fw_ref);
>   	return 0;
>   }
>   
> @@ -480,6 +482,7 @@ u32 xe_guc_pc_get_rpn_freq(struct xe_guc_pc *pc)
>   int xe_guc_pc_get_min_freq(struct xe_guc_pc *pc, u32 *freq)
>   {
>   	struct xe_gt *gt = pc_to_gt(pc);
> +	unsigned int fw_ref;
>   	int ret;
>   
>   	mutex_lock(&pc->freq_lock);
> @@ -493,9 +496,11 @@ int xe_guc_pc_get_min_freq(struct xe_guc_pc *pc, u32 *freq)
>   	 * GuC SLPC plays with min freq request when GuCRC is enabled
>   	 * Block RC6 for a more reliable read.
>   	 */
> -	ret = xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL);
> -	if (ret)
> -		goto out;
> +	fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL);
> +	if (!xe_force_wake_ref_has_domain(fw_ref, XE_FORCEWAKE_ALL)) {
> +		ret = -ETIMEDOUT;
> +		goto fw;
> +	}
>   
>   	ret = pc_action_query_task_state(pc);
>   	if (ret)
> @@ -504,7 +509,7 @@ int xe_guc_pc_get_min_freq(struct xe_guc_pc *pc, u32 *freq)
>   	*freq = pc_get_min_freq(pc);
>   
>   fw:
> -	XE_WARN_ON(xe_force_wake_put(gt_to_fw(gt), XE_FORCEWAKE_ALL));
> +	xe_force_wake_put(gt_to_fw(gt), fw_ref);
>   out:
>   	mutex_unlock(&pc->freq_lock);
>   	return ret;
> @@ -855,6 +860,7 @@ int xe_guc_pc_gucrc_disable(struct xe_guc_pc *pc)
>   {
>   	struct xe_device *xe = pc_to_xe(pc);
>   	struct xe_gt *gt = pc_to_gt(pc);
> +	unsigned int fw_ref;
>   	int ret = 0;
>   
>   	if (xe->info.skip_guc_pc)
> @@ -864,13 +870,15 @@ int xe_guc_pc_gucrc_disable(struct xe_guc_pc *pc)
>   	if (ret)
>   		return ret;
>   
> -	ret = xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL);
> -	if (ret)
> -		return ret;
> +	fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL);
> +	if (!xe_force_wake_ref_has_domain(fw_ref, XE_FORCEWAKE_ALL)) {
> +		xe_force_wake_put(gt_to_fw(gt), fw_ref);
> +		return -ETIMEDOUT;
> +	}
>   
>   	xe_gt_idle_disable_c6(gt);
>   
> -	XE_WARN_ON(xe_force_wake_put(gt_to_fw(gt), XE_FORCEWAKE_ALL));
> +	xe_force_wake_put(gt_to_fw(gt), fw_ref);
>   
>   	return 0;
>   }
> @@ -956,13 +964,16 @@ int xe_guc_pc_start(struct xe_guc_pc *pc)
>   	struct xe_device *xe = pc_to_xe(pc);
>   	struct xe_gt *gt = pc_to_gt(pc);
>   	u32 size = PAGE_ALIGN(sizeof(struct slpc_shared_data));
> +	unsigned int fw_ref;
>   	int ret;
>   
>   	xe_gt_assert(gt, xe_device_uc_enabled(xe));
>   
> -	ret = xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL);
> -	if (ret)
> -		return ret;
> +	fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL);
> +	if (!xe_force_wake_ref_has_domain(fw_ref, XE_FORCEWAKE_ALL)) {
> +		xe_force_wake_put(gt_to_fw(gt), fw_ref);
> +		return -ETIMEDOUT;
> +	}
>   
>   	if (xe->info.skip_guc_pc) {
>   		if (xe->info.platform != XE_PVC)
> @@ -1005,7 +1016,7 @@ int xe_guc_pc_start(struct xe_guc_pc *pc)
>   	ret = pc_action_setup_gucrc(pc, GUCRC_FIRMWARE_CONTROL);
>   
>   out:
> -	XE_WARN_ON(xe_force_wake_put(gt_to_fw(gt), XE_FORCEWAKE_ALL));
> +	xe_force_wake_put(gt_to_fw(gt), fw_ref);
>   	return ret;
>   }
>   
> @@ -1037,18 +1048,19 @@ static void xe_guc_pc_fini_hw(void *arg)
>   {
>   	struct xe_guc_pc *pc = arg;
>   	struct xe_device *xe = pc_to_xe(pc);
> +	unsigned int fw_ref;
>   
>   	if (xe_device_wedged(xe))
>   		return;
>   
> -	XE_WARN_ON(xe_force_wake_get(gt_to_fw(pc_to_gt(pc)), XE_FORCEWAKE_ALL));
> +	fw_ref = xe_force_wake_get(gt_to_fw(pc_to_gt(pc)), XE_FORCEWAKE_ALL);
>   	xe_guc_pc_gucrc_disable(pc);
>   	XE_WARN_ON(xe_guc_pc_stop(pc));
>   
>   	/* Bind requested freq to mert_freq_cap before unload */
>   	pc_set_cur_freq(pc, min(pc_max_freq_cap(pc), pc->rpe_freq));
>   
> -	xe_force_wake_put(gt_to_fw(pc_to_gt(pc)), XE_FORCEWAKE_ALL);
> +	xe_force_wake_put(gt_to_fw(pc_to_gt(pc)), fw_ref);
>   }
>   
>   /**
> diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
> index 0e5649b394b6..fc8ababc79fb 100644
> --- a/drivers/gpu/drm/xe/xe_guc_submit.c
> +++ b/drivers/gpu/drm/xe/xe_guc_submit.c
> @@ -1098,6 +1098,7 @@ guc_exec_queue_timedout_job(struct drm_sched_job *drm_job)
>   	struct xe_guc *guc = exec_queue_to_guc(q);
>   	const char *process_name = "no process";
>   	struct xe_device *xe = guc_to_xe(guc);
> +	unsigned int fw_ref;
>   	int err = -ETIME;
>   	pid_t pid = -1;
>   	int i = 0;
> @@ -1135,12 +1136,13 @@ guc_exec_queue_timedout_job(struct drm_sched_job *drm_job)
>   	if (!exec_queue_killed(q) && !xe->devcoredump.captured &&
>   	    !xe_guc_capture_get_matching_and_lock(job)) {
>   		/* take force wake before engine register manual capture */
> -		if (xe_force_wake_get(gt_to_fw(q->gt), XE_FORCEWAKE_ALL))
> +		fw_ref = xe_force_wake_get(gt_to_fw(q->gt), XE_FORCEWAKE_ALL);
> +		if (!xe_force_wake_ref_has_domain(fw_ref, XE_FORCEWAKE_ALL))
>   			xe_gt_info(q->gt, "failed to get forcewake for coredump capture\n");
>   
>   		xe_engine_snapshot_capture_for_job(job);
>   
> -		xe_force_wake_put(gt_to_fw(q->gt), XE_FORCEWAKE_ALL);
> +		xe_force_wake_put(gt_to_fw(q->gt), fw_ref);

LGTM.
Reviewed-by: Badal Nilawar <badal.nilawar@intel.com>

Regards,
Badal

>   	}
>   
>   	/*