Re: [Intel-gfx] [PATCH 6/7] drm/i915/hwmon: Expose power1_max_interval

Dixit, Ashutosh
2022-09-23T02:52:28Z

On Thu, 22 Sep 2022 00:13:00 -0700, Gupta, Anshuman wrote:
>

Hi Anshuman,

> > +static ssize_t
> > +hwm_power1_max_interval_store(struct device *dev,
> > + struct device_attribute *attr,
> > + const char *buf, size_t count)
> > +{
> > + struct hwm_drvdata *ddat = dev_get_drvdata(dev);
> > + struct i915_hwmon *hwmon = ddat->hwmon;
> > + long val, max_win, ret;
> > + u32 x, y, rxy, x_w = 2; /* 2 bits */
> > + u64 tau4, r;
> > +
> > +#define PKG_MAX_WIN_DEFAULT 0x12ull
> > +
> > + ret = kstrtoul(buf, 0, &val);
> > + if (ret)
> > + return ret;
> > +
> > + /*
> > + * val must be < max in hwmon interface units. The steps below are
> > + * explained in i915_power1_max_interval_show()
> > + */
> > + r = FIELD_PREP(PKG_MAX_WIN, PKG_MAX_WIN_DEFAULT);
>
> AFAIU we need to read r from PACKAGE_POWER_SKU reg untill unless it has
> some known issue?

The platform on which I tried had an incorrect value (that is why I didn't
read it from PACKAGE_POWER_SKU) but let me investigate it some more for
other platforms and get back.

> > + x = REG_FIELD_GET(PKG_MAX_WIN_X, r);
> > + y = REG_FIELD_GET(PKG_MAX_WIN_Y, r);
> > + tau4 = ((1 << x_w) | x) << y;
> > + max_win = mul_u64_u32_shr(tau4, SF_TIME, hwmon->scl_shift_time + x_w);
> > +
> > + if (val > max_win)
> > + return -EINVAL;
> > +
> > + /* val in hw units */
> > + val = DIV_ROUND_CLOSEST_ULL((u64)val << hwmon->scl_shift_time, SF_TIME);
> > + /* Convert to 1.x * power(2,y) */
> > + if (!val)
> > + return -EINVAL;
> > + y = ilog2(val);
> > + /* x = (val - (1 << y)) >> (y - 2); */
> > + x = (val - (1ul << y)) << x_w >> y;
> > +
> > + rxy = REG_FIELD_PREP(PKG_PWR_LIM_1_TIME_X, x) | REG_FIELD_PREP(PKG_PWR_LIM_1_TIME_Y, y);
> > +
> > + hwm_locked_with_pm_intel_uncore_rmw(ddat, hwmon->rg.pkg_rapl_limit,
> > + PKG_PWR_LIM_1_TIME, rxy);
> > + return count;
> > +}
> > +
> /snip
> > if (IS_ERR(hwmon_dev)) {
> > mutex_destroy(&hwmon->hwmon_lock);
> > i915->hwmon = NULL;
> > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > index 956e5298ef1e..68e7cc85dc53 100644
> > --- a/drivers/gpu/drm/i915/i915_reg.h
> > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > @@ -1811,6 +1811,9 @@
> > * *_PACKAGE_POWER_SKU - SKU power and timing parameters.
> > */
> > #define PKG_PKG_TDP GENMASK_ULL(14, 0)
> > +#define PKG_MAX_WIN GENMASK_ULL(54, 48)
> > +#define PKG_MAX_WIN_X GENMASK_ULL(54, 53)
> > +#define PKG_MAX_WIN_Y GENMASK_ULL(52, 48)
> These GENMASK fields needs a reg definition.

Yes this is the same _PACKAGE_POWER_SKU register so should get fixed when
we add it in Patch 3.

Thanks.
--
Ashutosh