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

Gupta, Anshuman
2022-09-22T07:13:29Z

On 9/16/2022 8:30 PM, Badal Nilawar wrote:
> From: Ashutosh Dixit <ashutosh.dixit@intel.com>
>
> Expose power1_max_interval, that is the tau corresponding to PL1. Some bit
> manipulation is needed because of the format of PKG_PWR_LIM_1_TIME in
> GT0_PACKAGE_RAPL_LIMIT register (1.x * power(2,y)).
>
> v2: Update date and kernel version in Documentation (Badal)
> v3: Cleaned up hwm_power1_max_interval_store() (Badal)
>
> Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
> Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
> Acked-by: Guenter Roeck <linux@roeck-us.net>
> ---
> .../ABI/testing/sysfs-driver-intel-i915-hwmon | 9 ++
> drivers/gpu/drm/i915/i915_hwmon.c | 114 +++++++++++++++++-
> drivers/gpu/drm/i915/i915_reg.h | 3 +
> drivers/gpu/drm/i915/intel_mchbar_regs.h | 4 +
> 4 files changed, 129 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
> index cc70596fff44..7995a885c9d6 100644
> --- a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
> +++ b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
> @@ -26,6 +26,15 @@ Description: RO. Card default power limit (default TDP setting).
>
> Only supported for particular Intel i915 graphics platforms.
>
> +What: /sys/devices/.../hwmon/hwmon/power1_max_interval
> +Date: September 2022
> +KernelVersion: 6
> +Contact: dri-devel@lists.freedesktop.org
> +Description: RW. Sustained power limit interval (Tau in PL1/Tau) in
> + milliseconds over which sustained power is averaged.
> +
> + Only supported for particular Intel i915 graphics platforms.
> +
> What: /sys/devices/.../hwmon/hwmon/power1_crit
> Date: September 2022
> KernelVersion: 6
> diff --git a/drivers/gpu/drm/i915/i915_hwmon.c b/drivers/gpu/drm/i915/i915_hwmon.c
> index bd9ba312c474..7d85a81bc39b 100644
> --- a/drivers/gpu/drm/i915/i915_hwmon.c
> +++ b/drivers/gpu/drm/i915/i915_hwmon.c
> @@ -20,11 +20,13 @@
> * - power - microwatts
> * - curr - milliamperes
> * - energy - microjoules
> + * - time - milliseconds
> */
> #define SF_VOLTAGE 1000
> #define SF_POWER 1000000
> #define SF_CURR 1000
> #define SF_ENERGY 1000000
> +#define SF_TIME 1000
>
> struct hwm_reg {
> i915_reg_t gt_perf_status;
> @@ -53,6 +55,7 @@ struct i915_hwmon {
> struct hwm_reg rg;
> int scl_shift_power;
> int scl_shift_energy;
> + int scl_shift_time;
> };
>
> static void
> @@ -161,6 +164,114 @@ hwm_energy(struct hwm_drvdata *ddat, long *energy)
> return 0;
> }
>
> +static ssize_t
> +hwm_power1_max_interval_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + struct hwm_drvdata *ddat = dev_get_drvdata(dev);
> + struct i915_hwmon *hwmon = ddat->hwmon;
> + intel_wakeref_t wakeref;
> + u32 r, x, y, x_w = 2; /* 2 bits */
> + u64 tau4, out;
> +
> + with_intel_runtime_pm(ddat->uncore->rpm, wakeref)
> + r = intel_uncore_read(ddat->uncore, hwmon->rg.pkg_rapl_limit);
> +
> + x = REG_FIELD_GET(PKG_PWR_LIM_1_TIME_X, r);
> + y = REG_FIELD_GET(PKG_PWR_LIM_1_TIME_Y, r);
> + /*
> + * tau = 1.x * power(2,y), x = bits(23:22), y = bits(21:17)
> + * = (4 | x) << (y - 2)
> + * where (y - 2) ensures a 1.x fixed point representation of 1.x
> + * However because y can be < 2, we compute
> + * tau4 = (4 | x) << y
> + * but add 2 when doing the final right shift to account for units
> + */
> + tau4 = ((1 << x_w) | x) << y;
> + /* val in hwmon interface units (millisec) */
> + out = mul_u64_u32_shr(tau4, SF_TIME, hwmon->scl_shift_time + x_w);
> +
> + return sysfs_emit(buf, "%llu\n", out);
> +}
> +
> +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?
> + 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.
Br,
Anshuman Gupta.
>
> #define CHV_CLK_CTL1 _MMIO(0x101100)
> #define VLV_CLK_CTL2 _MMIO(0x101104)
> diff --git a/drivers/gpu/drm/i915/intel_mchbar_regs.h b/drivers/gpu/drm/i915/intel_mchbar_regs.h
> index 1014d0b7cc16..9331a3c15fd1 100644
> --- a/drivers/gpu/drm/i915/intel_mchbar_regs.h
> +++ b/drivers/gpu/drm/i915/intel_mchbar_regs.h
> @@ -206,6 +206,10 @@
> #define RPE_MASK REG_GENMASK(15, 8)
> #define PCU_PACKAGE_RAPL_LIMIT _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x59a0)
> #define PKG_PWR_LIM_1 REG_GENMASK(14, 0)
> +#define PKG_PWR_LIM_1_EN REG_BIT(15)
> +#define PKG_PWR_LIM_1_TIME REG_GENMASK(23, 17)
> +#define PKG_PWR_LIM_1_TIME_X REG_GENMASK(23, 22)
> +#define PKG_PWR_LIM_1_TIME_Y REG_GENMASK(21, 17)
>
> /* snb MCH registers for priority tuning */
> #define MCH_SSKPD _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5d10)