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

[Srivatsa, Anusha]

>-----Original Message-----
>From: Chris Wilson [mailto:chris at chris-wilson.co.uk]
>Sent: Friday, December 16, 2016 10:47 AM
>To: Srivatsa, Anusha <anusha.srivatsa at intel.com>
>Cc: Hiler, Arkadiusz <arkadiusz.hiler 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 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.
Ah! Got it. Thanks.

Cheers,
Anusha
>-Chris
>
>--
>Chris Wilson, Intel Open Source Technology Centre