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

Badal Nilawar
2022-09-26T17:50:27Z

From: Ashutosh Dixit <ashutosh.dixit@intel.com>

Expose power1_max_interval, that is the tau corresponding to PL1, as a
custom hwmon attribute. 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)
v4:
- Fixed review comments (Anshuman)
- In hwm_power1_max_interval_store() get PKG_MAX_WIN from
pkg_power_sku when it is valid (Ashutosh)
- KernelVersion: 6.2, Date: February 2023 in doc (Tvrtko)
v5: On some of the DGFX setups it is seen that although pkg_power_sku
is valid the field PKG_WIN_MAX is not populated. So it is
decided to stick to default value of PKG_WIN_MAX (Ashutosh)

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 | 115 +++++++++++++++++-
drivers/gpu/drm/i915/intel_mchbar_regs.h | 7 ++
3 files changed, 130 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
index f9d6d3b08bba..19b9fe3ef237 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: February 2023
+KernelVersion: 6.2
+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: February 2023
KernelVersion: 6.2
diff --git a/drivers/gpu/drm/i915/i915_hwmon.c b/drivers/gpu/drm/i915/i915_hwmon.c
index 2394fa789793..641143956c45 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 +164,115 @@ 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);
+
+ 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;
+}
+
+static SENSOR_DEVICE_ATTR(power1_max_interval, 0664,
+ hwm_power1_max_interval_show,
+ hwm_power1_max_interval_store, 0);
+
+static struct attribute *hwm_attributes[] = {
+ &sensor_dev_attr_power1_max_interval.dev_attr.attr,
+ NULL
+};
+
+static umode_t hwm_attributes_visible(struct kobject *kobj,
+ struct attribute *attr, int index)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ struct hwm_drvdata *ddat = dev_get_drvdata(dev);
+ struct i915_hwmon *hwmon = ddat->hwmon;
+
+ if (attr == &sensor_dev_attr_power1_max_interval.dev_attr.attr)
+ return i915_mmio_reg_valid(hwmon->rg.pkg_rapl_limit) ? attr->mode : 0;
+ else
+ return 0;
+}
+
+static const struct attribute_group hwm_attrgroup = {
+ .attrs = hwm_attributes,
+ .is_visible = hwm_attributes_visible,
+};
+
+static const struct attribute_group *hwm_groups[] = {
+ &hwm_attrgroup,
+ NULL
+};
+
static const struct hwmon_channel_info *hwm_info[] = {
HWMON_CHANNEL_INFO(in, HWMON_I_INPUT),
HWMON_CHANNEL_INFO(power, HWMON_P_MAX | HWMON_P_RATED_MAX | HWMON_P_CRIT),
@@ -472,6 +584,7 @@ hwm_get_preregistration_info(struct drm_i915_private *i915)

hwmon->scl_shift_power = REG_FIELD_GET(PKG_PWR_UNIT, val_sku_unit);
hwmon->scl_shift_energy = REG_FIELD_GET(PKG_ENERGY_UNIT, val_sku_unit);
+ hwmon->scl_shift_time = REG_FIELD_GET(PKG_TIME_UNIT, val_sku_unit);

/*
* Initialize 'struct hwm_energy_info', i.e. set fields to the
@@ -510,7 +623,7 @@ void i915_hwmon_register(struct drm_i915_private *i915)
hwmon_dev = devm_hwmon_device_register_with_info(dev, ddat->name,
ddat,
&hwm_chip_info,
- NULL);
+ hwm_groups);
if (IS_ERR(hwmon_dev)) {
i915->hwmon = NULL;
return;
diff --git a/drivers/gpu/drm/i915/intel_mchbar_regs.h b/drivers/gpu/drm/i915/intel_mchbar_regs.h
index bd42fb66e297..64aa1e9be463 100644
--- a/drivers/gpu/drm/i915/intel_mchbar_regs.h
+++ b/drivers/gpu/drm/i915/intel_mchbar_regs.h
@@ -194,6 +194,9 @@
*/
#define PCU_PACKAGE_POWER_SKU _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5930)
#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)

#define PCU_PACKAGE_POWER_SKU_UNIT _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5938)
#define PKG_PWR_UNIT REG_GENMASK(3, 0)
@@ -212,6 +215,10 @@
#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)
--
2.25.1