[Intel-gfx] [v2] drm/i915/selftest/gsc: Ensure GSC Proxy init completes before selftests

[Dong, Zhanjun]

See my comments below.

> -----Original Message-----
> From: Alan Previn <alan.previn.teres.alexis at intel.com>
> Sent: May 30, 2023 1:01 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: dri-devel at lists.freedesktop.org; Alan Previn
> <alan.previn.teres.alexis at intel.com>
> Subject: [v2] drm/i915/selftest/gsc: Ensure GSC Proxy init completes before
> selftests
> 
> On MTL, if the GSC Proxy init flows haven't completed, submissions to the
> GSC engine will fail. Those init flows are dependent on the mei's
> gsc_proxy component that is loaded in parallel with i915 and a
> worker that could potentially start after i915 driver init is done.
> 
> That said, all subsytems that access the GSC engine today does check
> for such init flow completion before using the GSC engine. However,
> selftests currently don't wait on anything before starting.
> 
> To fix this, add a waiter function at the start of __run_selftests
> that waits for gsc-proxy init flows to complete. While implementing this,
> use an table of function pointers so its scalable to add additional
> waiter functions for future such "wait on dependency" cases that.
> 
> Difference from prior versions:
>    v1: Based on internal testing, increase the timeout for gsc-proxy
>        specific case to 8 seconds.
> 
> Signed-off-by: Alan Previn <alan.previn.teres.alexis at intel.com>
> ---
>  .../gpu/drm/i915/selftests/i915_selftest.c    | 61 +++++++++++++++++++
>  1 file changed, 61 insertions(+)
> 
> 
> base-commit: 0ae4ee2c735979030a0219218081eee661606921
> 
> diff --git a/drivers/gpu/drm/i915/selftests/i915_selftest.c
> b/drivers/gpu/drm/i915/selftests/i915_selftest.c
> index 39da0fb0d6d2..77168a7a7e3f 100644
> --- a/drivers/gpu/drm/i915/selftests/i915_selftest.c
> +++ b/drivers/gpu/drm/i915/selftests/i915_selftest.c
> @@ -24,6 +24,8 @@
>  #include <linux/random.h>
> 
>  #include "gt/intel_gt_pm.h"
> +#include "gt/uc/intel_gsc_fw.h"
> +
>  #include "i915_driver.h"
>  #include "i915_drv.h"
>  #include "i915_selftest.h"
> @@ -127,6 +129,63 @@ static void set_default_test_all(struct selftest *st,
> unsigned int count)
>  		st[i].enabled = true;
>  }
> 
> +static int
> +__wait_gsc_proxy_completed(struct drm_i915_private *i915,
> +			   unsigned long timeout_ms)
> +{
> +	bool need_to_wait = (IS_ENABLED(CONFIG_INTEL_MEI_GSC_PROXY)
> &&
> +			     i915->media_gt &&
> +			     HAS_ENGINE(i915->media_gt, GSC0) &&
> +			     intel_uc_fw_is_loadable(&i915->media_gt-
> >uc.gsc.fw));
> +
> +	/*
> +	 * For gsc proxy component loading + init, we need a much longer
> timeout
> +	 * than what CI selftest infrastrucutre currently uses. This longer wait
> +	 * period depends on the kernel config and component driver load
> ordering
> +	 */
> +	if (timeout_ms < 8000)
> +		timeout_ms = 8000;


Lgtm, just an concern about the fixed number here, shall we set the minimal here, or let i915_selftest.timeout_ms take control? Thus no longer need coding change here in the future.

Reviewed-by: Zhanjun Dong <zhanjun.dong at intel.com>
> +
> +	if (need_to_wait &&
> +	    (wait_for(intel_gsc_uc_fw_proxy_init_done(&i915->media_gt-
> >uc.gsc),
> +	    timeout_ms)))
> +		return -ETIME;
> +
> +	return 0;
> +}
> +
> +struct __startup_waiter {
> +	const char *name;
> +	int (*wait_to_completed)(struct drm_i915_private *i915, unsigned
> long timeout_ms);
> +};
> +
> +static struct __startup_waiter all_startup_waiters[] = { \
> +	{"gsc_proxy", __wait_gsc_proxy_completed} \
> +	};
> +
> +static int __wait_on_all_system_dependencies(struct drm_i915_private
> *i915)
> +{
> +	struct __startup_waiter *waiter = all_startup_waiters;
> +	int count = ARRAY_SIZE(all_startup_waiters);
> +	int ret;
> +
> +	if (!waiter || !count || !i915)
> +		return 0;
> +
> +	for (; count--; waiter++) {
> +		if (!waiter->wait_to_completed)
> +			continue;
> +		ret = waiter->wait_to_completed(i915,
> i915_selftest.timeout_ms);
> +		if (ret) {
> +			pr_info(DRIVER_NAME ": Pre-selftest waiter %s failed
> with %d\n",
> +				waiter->name, ret);
> +			return ret;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
>  static int __run_selftests(const char *name,
>  			   struct selftest *st,
>  			   unsigned int count,
> @@ -134,6 +193,8 @@ static int __run_selftests(const char *name,
>  {
>  	int err = 0;
> 
> +	__wait_on_all_system_dependencies(data);
> +
>  	while (!i915_selftest.random_seed)
>  		i915_selftest.random_seed = get_random_u32();
>