[Intel-gfx] [PATCH 8/8] drm/i915/get_params: Add HuC status to getparams

[Chris Wilson]

On Fri, Dec 16, 2016 at 06:31:46PM +0000, Srivatsa, Anusha wrote:
> 
> 
> >-----Original Message-----
> >From: Chris Wilson [mailto:chris at chris-wilson.co.uk]
> >Sent: Friday, December 16, 2016 8:31 AM
> >To: Hiler, Arkadiusz <arkadiusz.hiler at intel.com>
> >Cc: Srivatsa, Anusha <anusha.srivatsa at intel.com>; intel-
> >gfx at lists.freedesktop.org
> >Subject: Re: [Intel-gfx] [PATCH 8/8] drm/i915/get_params: Add HuC status to
> >getparams
> >
> >On Fri, Dec 16, 2016 at 05:21:38PM +0100, Arkadiusz Hiler wrote:
> >> On Fri, Dec 16, 2016 at 04:12:36PM +0000, Chris Wilson wrote:
> >> > On Fri, Dec 16, 2016 at 03:43:46PM +0100, Arkadiusz Hiler wrote:
> >> > > On Thu, Dec 15, 2016 at 10:42:53PM +0000, Chris Wilson wrote:
> >> > > > On Thu, Dec 15, 2016 at 02:29:50PM -0800, anushasr wrote:
> >> > > > > From: Peter Antoine <peter.antoine at intel.com>
> >> > > > >
> >> > > > > This patch will allow for getparams to return the status of the HuC.
> >> > > > > As the HuC has to be validated by the GuC this patch uses the
> >> > > > > validated status to show when the HuC is loaded and ready for
> >> > > > > use. You cannot use the loaded status as with the GuC as the
> >> > > > > HuC is verified after it is loaded and is not usable until it is verified.
> >> > > > >
> >> > > > > v2: removed the forewakes as the registers are already force-woken.
> >> > > > >      (T.Ursulin)
> >> > > > > v4: rebased.
> >> > > > > v5: rebased on top of drm-tip.
> >> > > > > v6: rebased. Removed any reference to intel_huc.h
> >> > > > > v7: rebased. Rename I915_PARAM_HAS_HUC to
> >I915_PARAM_HUC_STATUS.
> >> > > > > Remove intel_is_huc_valid() since it is used only in one place.
> >> > > > > Put the case of I915_PARAM_HAS_HUC() in the right place.
> >> > > > >
> >> > > > > Signed-off-by: Peter Antoine <peter.antoine at intel.com>
> >> > > > > Reviewed-by: Arkadiusz Hiler <arkadiusz.hiler at intel.com>
> >> > > > > ---
> >> > > > >  drivers/gpu/drm/i915/i915_drv.c         | 4 ++++
> >> > > > >  drivers/gpu/drm/i915/intel_huc_loader.c | 1 -
> >> > > > >  include/uapi/drm/i915_drm.h             | 1 +
> >> > > > >  3 files changed, 5 insertions(+), 1 deletion(-)
> >> > > > >
> >> > > > > diff --git a/drivers/gpu/drm/i915/i915_drv.c
> >> > > > > b/drivers/gpu/drm/i915/i915_drv.c index 85a47c2..0bc016d
> >> > > > > 100644
> >> > > > > --- a/drivers/gpu/drm/i915/i915_drv.c
> >> > > > > +++ b/drivers/gpu/drm/i915/i915_drv.c
> >> > > > > @@ -49,6 +49,7 @@
> >> > > > >  #include "i915_trace.h"
> >> > > > >  #include "i915_vgpu.h"
> >> > > > >  #include "intel_drv.h"
> >> > > > > +#include "intel_uc.h"
> >> > > > >
> >> > > > >  static struct drm_driver driver;
> >> > > > >
> >> > > > > @@ -315,6 +316,9 @@ static int i915_getparam(struct drm_device
> >*dev, void *data,
> >> > > > >  	case I915_PARAM_MIN_EU_IN_POOL:
> >> > > > >  		value = INTEL_INFO(dev_priv)->sseu.min_eu_in_pool;
> >> > > > >  		break;
> >> > > > > +	case I915_PARAM_HUC_STATUS:
> >> > > > > +		value = I915_READ(HUC_STATUS2) &
> >HUC_FW_VERIFIED;
> >> > > >
> >> > > > Same question as last time: does the device need to be awake? We
> >> > > > know is one of the GT power wells, so presumably we need an
> >> > > > rpm_get/rpm_put as well to access the register.
> >> > > > -Chris
> >> > >
> >> > > I get:
> >> > >
> >> > > [ 1588.570174] [drm:i915_huc_load_status_info [i915]] HUC_STATUS2
> >> > > PRE  24704 [ 1588.571285] [drm:intel_runtime_suspend [i915]]
> >> > > Suspending device [ 1588.575768] [drm:intel_runtime_suspend
> >> > > [i915]] Device suspended [ 1588.577156]
> >> > > [drm:i915_huc_load_status_info [i915]] HUC_STATUS2 POST 24704 [
> >> > > 1588.578259] [drm:intel_runtime_resume [i915]] Resuming device
> >> > >
> >> > > consistently from:
> >> > >
> >> > > value = I915_READ(HUC_STATUS2);
> >> > > DRM_DEBUG_DRIVER("HUC_STATUS2 PRE  %d\n", value);
> >> > > i915_pm_ops.runtime_suspend(dev_priv->drm.dev);
> >> > >
> >> > > value = I915_READ(HUC_STATUS2);
> >> > > DRM_DEBUG_DRIVER("HUC_STATUS2 POST %d\n", value);
> >> > > i915_pm_ops.runtime_resume(dev_priv->drm.dev);
> >> >
> >> > Also do the test with i915.mmio_debug=9999 -Chris
> >>
> >> Same effect. Works.
> Thanks Arek for confirming.
> 
> >Ok, then just mark up that we don't need rpm here so that we don't freak out in
> >future scans for mmio access outside of rpm.
> >-Chris
> Chris, v2 as changed by Tvrtko suggests that forcewakes are removed since the register is force waken. Are you suggesting that adding that rpm not  being required in the commit message will make things much more clearer?

No, if you are eschewing taking rpm around mmio access, I want that
commented upon in the code so that it is visible the next time we do an
audit for rpm abuse/misuse.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre