Re: [PATCH v8 08/26] drm/xe/gsc: Update handling of xe_force_wake_get return

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

On 08-10-2024 12:40, 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. 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()
> 
> v5
> - return unsigned int for xe_force_wake_get()
> - No need to WARN from caller in case of forcewake get failure.
> 
> v7
> - Fix commit message
> 
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@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_gsc.c       | 23 +++++++++++------------
>   drivers/gpu/drm/xe/xe_gsc_proxy.c |  9 ++++-----
>   2 files changed, 15 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gsc.c b/drivers/gpu/drm/xe/xe_gsc.c
> index 783b09bf3681..1eb791ddc375 100644
> --- a/drivers/gpu/drm/xe/xe_gsc.c
> +++ b/drivers/gpu/drm/xe/xe_gsc.c
> @@ -261,19 +261,17 @@ static int gsc_upload_and_init(struct xe_gsc *gsc)
>   {
>   	struct xe_gt *gt = gsc_to_gt(gsc);
>   	struct xe_tile *tile = gt_to_tile(gt);
> +	unsigned int fw_ref;
>   	int ret;
>   
>   	if (XE_WA(tile->primary_gt, 14018094691)) {
> -		ret = xe_force_wake_get(gt_to_fw(tile->primary_gt), XE_FORCEWAKE_ALL);
> +		fw_ref = xe_force_wake_get(gt_to_fw(tile->primary_gt), XE_FORCEWAKE_ALL);
>   
>   		/*
>   		 * If the forcewake fails we want to keep going, because the worst
>   		 * case outcome in failing to apply the WA is that PXP won't work,
> -		 * which is not fatal. We still throw a warning so the issue is
> -		 * seen if it happens.
> +		 * which is not fatal. Forcewake get warns implicitly in case of failure
>   		 */
> -		xe_gt_WARN_ON(tile->primary_gt, ret);
> -
>   		xe_gt_mcr_multicast_write(tile->primary_gt,
>   					  EU_SYSTOLIC_LIC_THROTTLE_CTL_WITH_LOCK,
>   					  EU_SYSTOLIC_LIC_THROTTLE_CTL_LOCK_BIT);
> @@ -282,7 +280,7 @@ static int gsc_upload_and_init(struct xe_gsc *gsc)
>   	ret = gsc_upload(gsc);
>   
>   	if (XE_WA(tile->primary_gt, 14018094691))
> -		xe_force_wake_put(gt_to_fw(tile->primary_gt), XE_FORCEWAKE_ALL);
> +		xe_force_wake_put(gt_to_fw(tile->primary_gt), fw_ref);
>   
>   	if (ret)
>   		return ret;
> @@ -352,6 +350,7 @@ static void gsc_work(struct work_struct *work)
>   	struct xe_gsc *gsc = container_of(work, typeof(*gsc), work);
>   	struct xe_gt *gt = gsc_to_gt(gsc);
>   	struct xe_device *xe = gt_to_xe(gt);
> +	unsigned int fw_ref;
>   	u32 actions;
>   	int ret;
>   
> @@ -361,7 +360,7 @@ static void gsc_work(struct work_struct *work)
>   	spin_unlock_irq(&gsc->lock);
>   
>   	xe_pm_runtime_get(xe);
> -	xe_gt_WARN_ON(gt, xe_force_wake_get(gt_to_fw(gt), XE_FW_GSC));
> +	fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FW_GSC);
>   
>   	if (actions & GSC_ACTION_ER_COMPLETE) {
>   		ret = gsc_er_complete(gt);
> @@ -381,7 +380,7 @@ static void gsc_work(struct work_struct *work)
>   		xe_gsc_proxy_request_handler(gsc);
>   
>   out:
> -	xe_force_wake_put(gt_to_fw(gt), XE_FW_GSC);
> +	xe_force_wake_put(gt_to_fw(gt), fw_ref);
>   	xe_pm_runtime_put(xe);
>   }
>   
> @@ -601,7 +600,7 @@ void xe_gsc_print_info(struct xe_gsc *gsc, struct drm_printer *p)
>   {
>   	struct xe_gt *gt = gsc_to_gt(gsc);
>   	struct xe_mmio *mmio = &gt->mmio;
> -	int err;
> +	unsigned int fw_ref;
>   
>   	xe_uc_fw_print(&gsc->fw, p);
>   
> @@ -610,8 +609,8 @@ void xe_gsc_print_info(struct xe_gsc *gsc, struct drm_printer *p)
>   	if (!xe_uc_fw_is_enabled(&gsc->fw))
>   		return;
>   
> -	err = xe_force_wake_get(gt_to_fw(gt), XE_FW_GSC);
> -	if (err)
> +	fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FW_GSC);
> +	if (!fw_ref)
>   		return;
>   
>   	drm_printf(p, "\nHECI1 FWSTS: 0x%08x 0x%08x 0x%08x 0x%08x 0x%08x 0x%08x\n",
> @@ -622,5 +621,5 @@ void xe_gsc_print_info(struct xe_gsc *gsc, struct drm_printer *p)
>   			xe_mmio_read32(mmio, HECI_FWSTS5(MTL_GSC_HECI1_BASE)),
>   			xe_mmio_read32(mmio, HECI_FWSTS6(MTL_GSC_HECI1_BASE)));
>   
> -	xe_force_wake_put(gt_to_fw(gt), XE_FW_GSC);
> +	xe_force_wake_put(gt_to_fw(gt), fw_ref);
>   }
> diff --git a/drivers/gpu/drm/xe/xe_gsc_proxy.c b/drivers/gpu/drm/xe/xe_gsc_proxy.c
> index 6d89c22ae811..fc64b45d324b 100644
> --- a/drivers/gpu/drm/xe/xe_gsc_proxy.c
> +++ b/drivers/gpu/drm/xe/xe_gsc_proxy.c
> @@ -450,22 +450,21 @@ void xe_gsc_proxy_remove(struct xe_gsc *gsc)
>   {
>   	struct xe_gt *gt = gsc_to_gt(gsc);
>   	struct xe_device *xe = gt_to_xe(gt);
> -	int err = 0;
> +	unsigned int fw_ref = 0;
>   
>   	if (!gsc->proxy.component_added)
>   		return;
>   
>   	/* disable HECI2 IRQs */
>   	xe_pm_runtime_get(xe);
> -	err = xe_force_wake_get(gt_to_fw(gt), XE_FW_GSC);
> -	if (err)
> +	fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FW_GSC);
> +	if (!fw_ref)
>   		xe_gt_err(gt, "failed to get forcewake to disable GSC interrupts\n");
>   
>   	/* try do disable irq even if forcewake failed */
>   	gsc_proxy_irq_toggle(gsc, false);
>   
> -	if (!err)
> -		xe_force_wake_put(gt_to_fw(gt), XE_FW_GSC);
> +	xe_force_wake_put(gt_to_fw(gt), fw_ref);

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

Regards,
Badal

>   	xe_pm_runtime_put(xe);
>   
>   	xe_gsc_wait_for_worker_completion(gsc);