From: Dale B Stimson <dale.b.stim...@intel.com>

Use i915 HWMON to display/modify dGfx power PL1 limit and TDP setting.

v2:
  - Fix review comments (Ashutosh)
  - Do not restore power1_max upon module unload/load sequence
    because on production systems modules are always loaded
    and not unloaded/reloaded (Ashutosh)
  - Fix review comments (Jani)
  - Remove endianness conversion (Ashutosh)
v3: Add power1_rated_max (Ashutosh)
v4:
  - Use macro HWMON_CHANNEL_INFO to define power channel (Guenter)
  - Update the date and kernel version in Documentation (Badal)
v5: Use hwm_ prefix for static functions (Ashutosh)

Cc: Guenter Roeck <li...@roeck-us.net>
Signed-off-by: Dale B Stimson <dale.b.stim...@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.di...@intel.com>
Signed-off-by: Riana Tauro <riana.ta...@intel.com>
Signed-off-by: Badal Nilawar <badal.nila...@intel.com>
Acked-by: Guenter Roeck <li...@roeck-us.net>
---
 .../ABI/testing/sysfs-driver-intel-i915-hwmon |  20 ++
 drivers/gpu/drm/i915/i915_hwmon.c             | 175 +++++++++++++++++-
 drivers/gpu/drm/i915/i915_reg.h               |  16 ++
 drivers/gpu/drm/i915/intel_mchbar_regs.h      |   7 +
 4 files changed, 216 insertions(+), 2 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon 
b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
index 24c4b7477d51..9a2d10edfce8 100644
--- a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
+++ b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
@@ -5,3 +5,23 @@ Contact:       dri-de...@lists.freedesktop.org
 Description:   RO. Current Voltage in millivolt.
 
                Only supported for particular Intel i915 graphics platforms.
+
+What:          /sys/devices/.../hwmon/hwmon<i>/power1_max
+Date:          June 2022
+KernelVersion: 5.19
+Contact:       dri-de...@lists.freedesktop.org
+Description:   RW. Card reactive sustained  (PL1/Tau) power limit in 
microwatts.
+
+               The power controller will throttle the operating frequency
+               if the power averaged over a window (typically seconds)
+               exceeds this limit.
+
+               Only supported for particular Intel i915 graphics platforms.
+
+What:          /sys/devices/.../hwmon/hwmon<i>/power1_rated_max
+Date:          June 2022
+KernelVersion: 5.19
+Contact:       dri-de...@lists.freedesktop.org
+Description:   RO. Card default power limit (default TDP setting).
+
+               Only supported for particular Intel i915 graphics platforms.
diff --git a/drivers/gpu/drm/i915/i915_hwmon.c 
b/drivers/gpu/drm/i915/i915_hwmon.c
index 1893efe796a4..ccda7b690435 100644
--- a/drivers/gpu/drm/i915/i915_hwmon.c
+++ b/drivers/gpu/drm/i915/i915_hwmon.c
@@ -12,8 +12,22 @@
 #include "intel_mchbar_regs.h"
 #include "gt/intel_gt_regs.h"
 
+/*
+ * SF_* - scale factors for particular quantities according to hwmon spec.
+ * - power  - microwatts
+ */
+#define SF_POWER       1000000
+
+#define FIELD_SHIFT(__mask)                                \
+       (BUILD_BUG_ON_ZERO(!__builtin_constant_p(__mask)) + \
+               BUILD_BUG_ON_ZERO((__mask) == 0) +          \
+               __bf_shf(__mask))
+
 struct hwm_reg {
        i915_reg_t gt_perf_status;
+       i915_reg_t pkg_power_sku_unit;
+       i915_reg_t pkg_power_sku;
+       i915_reg_t pkg_rapl_limit;
 };
 
 struct hwm_drvdata {
@@ -27,10 +41,69 @@ struct i915_hwmon {
        struct hwm_drvdata ddat;
        struct mutex hwmon_lock;                /* counter overflow logic and 
rmw */
        struct hwm_reg rg;
+       int scl_shift_power;
 };
 
+static void
+hwm_locked_with_pm_intel_uncore_rmw(struct hwm_drvdata *ddat,
+                                   i915_reg_t reg, u32 clear, u32 set)
+{
+       struct i915_hwmon *hwmon = ddat->hwmon;
+       struct intel_uncore *uncore = ddat->uncore;
+       intel_wakeref_t wakeref;
+
+       mutex_lock(&hwmon->hwmon_lock);
+
+       with_intel_runtime_pm(uncore->rpm, wakeref)
+               intel_uncore_rmw(uncore, reg, clear, set);
+
+       mutex_unlock(&hwmon->hwmon_lock);
+}
+
+/*
+ * This function's return type of u64 allows for the case where the scaling
+ * of the field taken from the 32-bit register value might cause a result to
+ * exceed 32 bits.
+ */
+static u64
+hwm_field_read_and_scale(struct hwm_drvdata *ddat, i915_reg_t rgadr,
+                        u32 field_msk, int field_shift,
+                        int nshift, u32 scale_factor)
+{
+       struct intel_uncore *uncore = ddat->uncore;
+       intel_wakeref_t wakeref;
+       u32 reg_value;
+
+       with_intel_runtime_pm(uncore->rpm, wakeref)
+               reg_value = intel_uncore_read(uncore, rgadr);
+
+       reg_value = (reg_value & field_msk) >> field_shift;
+
+       return mul_u64_u32_shr(reg_value, scale_factor, nshift);
+}
+
+static void
+hwm_field_scale_and_write(struct hwm_drvdata *ddat, i915_reg_t rgadr,
+                         u32 field_msk, int field_shift,
+                         int nshift, unsigned int scale_factor, long lval)
+{
+       u32 nval;
+       u32 bits_to_clear;
+       u32 bits_to_set;
+
+       /* Computation in 64-bits to avoid overflow. Round to nearest. */
+       nval = DIV_ROUND_CLOSEST_ULL((u64)lval << nshift, scale_factor);
+
+       bits_to_clear = field_msk;
+       bits_to_set = (nval << field_shift) & field_msk;
+
+       hwm_locked_with_pm_intel_uncore_rmw(ddat, rgadr,
+                                           bits_to_clear, bits_to_set);
+}
+
 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),
        NULL
 };
 
@@ -64,6 +137,67 @@ hwm_in_read(struct hwm_drvdata *ddat, u32 attr, long *val)
        }
 }
 
+static umode_t
+hwm_power_is_visible(const struct hwm_drvdata *ddat, u32 attr, int chan)
+{
+       struct i915_hwmon *hwmon = ddat->hwmon;
+
+       switch (attr) {
+       case hwmon_power_max:
+               return i915_mmio_reg_valid(hwmon->rg.pkg_rapl_limit) ? 0664 : 0;
+       case hwmon_power_rated_max:
+               return i915_mmio_reg_valid(hwmon->rg.pkg_power_sku) ? 0444 : 0;
+       default:
+               return 0;
+       }
+}
+
+static int
+hwm_power_read(struct hwm_drvdata *ddat, u32 attr, int chan, long *val)
+{
+       struct i915_hwmon *hwmon = ddat->hwmon;
+
+       switch (attr) {
+       case hwmon_power_max:
+               *val = hwm_field_read_and_scale(ddat,
+                                               hwmon->rg.pkg_rapl_limit,
+                                               PKG_PWR_LIM_1,
+                                               FIELD_SHIFT(PKG_PWR_LIM_1),
+                                               hwmon->scl_shift_power,
+                                               SF_POWER);
+               return 0;
+       case hwmon_power_rated_max:
+               *val = hwm_field_read_and_scale(ddat,
+                                               hwmon->rg.pkg_power_sku,
+                                               PKG_PKG_TDP,
+                                               FIELD_SHIFT(PKG_PKG_TDP),
+                                               hwmon->scl_shift_power,
+                                               SF_POWER);
+               return 0;
+       default:
+               return -EOPNOTSUPP;
+       }
+}
+
+static int
+hwm_power_write(struct hwm_drvdata *ddat, u32 attr, int chan, long val)
+{
+       struct i915_hwmon *hwmon = ddat->hwmon;
+
+       switch (attr) {
+       case hwmon_power_max:
+               hwm_field_scale_and_write(ddat,
+                                         hwmon->rg.pkg_rapl_limit,
+                                         PKG_PWR_LIM_1,
+                                         FIELD_SHIFT(PKG_PWR_LIM_1),
+                                         hwmon->scl_shift_power,
+                                         SF_POWER, val);
+               return 0;
+       default:
+               return -EOPNOTSUPP;
+       }
+}
+
 static umode_t
 hwm_is_visible(const void *drvdata, enum hwmon_sensor_types type,
               u32 attr, int channel)
@@ -73,6 +207,8 @@ hwm_is_visible(const void *drvdata, enum hwmon_sensor_types 
type,
        switch (type) {
        case hwmon_in:
                return hwm_in_is_visible(ddat, attr);
+       case hwmon_power:
+               return hwm_power_is_visible(ddat, attr, channel);
        default:
                return 0;
        }
@@ -87,6 +223,8 @@ hwm_read(struct device *dev, enum hwmon_sensor_types type, 
u32 attr,
        switch (type) {
        case hwmon_in:
                return hwm_in_read(ddat, attr, val);
+       case hwmon_power:
+               return hwm_power_read(ddat, attr, channel, val);
        default:
                return -EOPNOTSUPP;
        }
@@ -96,7 +234,11 @@ static int
 hwm_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
          int channel, long val)
 {
+       struct hwm_drvdata *ddat = dev_get_drvdata(dev);
+
        switch (type) {
+       case hwmon_power:
+               return hwm_power_write(ddat, attr, channel, val);
        default:
                return -EOPNOTSUPP;
        }
@@ -117,11 +259,40 @@ static void
 hwm_get_preregistration_info(struct drm_i915_private *i915)
 {
        struct i915_hwmon *hwmon = i915->hwmon;
+       struct intel_uncore *uncore = &i915->uncore;
+       intel_wakeref_t wakeref;
+       u32 val_sku_unit;
 
-       if (IS_DG1(i915) || IS_DG2(i915))
+       if (IS_DG1(i915) || IS_DG2(i915)) {
                hwmon->rg.gt_perf_status = GEN12_RPSTAT1;
-       else
+               hwmon->rg.pkg_power_sku_unit = PCU_PACKAGE_POWER_SKU_UNIT;
+               hwmon->rg.pkg_power_sku = INVALID_MMIO_REG;
+               hwmon->rg.pkg_rapl_limit = PCU_PACKAGE_RAPL_LIMIT;
+       } else {
                hwmon->rg.gt_perf_status = INVALID_MMIO_REG;
+               hwmon->rg.pkg_power_sku_unit = INVALID_MMIO_REG;
+               hwmon->rg.pkg_power_sku = INVALID_MMIO_REG;
+               hwmon->rg.pkg_rapl_limit = INVALID_MMIO_REG;
+       }
+
+       with_intel_runtime_pm(uncore->rpm, wakeref) {
+               /*
+                * The contents of register hwmon->rg.pkg_power_sku_unit do not 
change,
+                * so read it once and store the shift values.
+                *
+                * For some platforms, this value is defined as available "for 
all
+                * tiles", with the values consistent across all tiles.
+                * In this case, use the tile 0 value for all.
+                */
+               if (i915_mmio_reg_valid(hwmon->rg.pkg_power_sku_unit)) {
+                       val_sku_unit = intel_uncore_read(uncore,
+                                                        
hwmon->rg.pkg_power_sku_unit);
+               } else {
+                       val_sku_unit = 0;
+               }
+
+               hwmon->scl_shift_power = REG_FIELD_GET(PKG_PWR_UNIT, 
val_sku_unit);
+       }
 }
 
 void i915_hwmon_register(struct drm_i915_private *i915)
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 50d7bfd541ad..78c7ce781c22 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1866,6 +1866,22 @@
 #define   POWER_LIMIT_1_MASK           REG_BIT(11)
 #define   POWER_LIMIT_2_MASK           REG_BIT(12)
 
+/*
+ * *_PACKAGE_POWER_SKU - SKU power and timing parameters.
+ * Used herein as a 64-bit register.
+ * These masks are defined using GENMASK_ULL as REG_GENMASK is limited to u32
+ * and as GENMASK is "long" and therefore 32-bits on a 32-bit system.
+ * PKG_PKG_TDP, PKG_MIN_PWR, and PKG_MAX_PWR are scaled in the same way as
+ * PKG_PWR_LIM_*, above.
+ * PKG_MAX_WIN has sub-fields for x and y, and has the value: is 1.x * 2^y.
+ */
+#define   PKG_PKG_TDP                  GENMASK_ULL(14, 0)
+#define   PKG_MIN_PWR                  GENMASK_ULL(30, 16)
+#define   PKG_MAX_PWR                  GENMASK_ULL(46, 32)
+#define   PKG_MAX_WIN                  GENMASK_ULL(54, 48)
+#define     PKG_MAX_WIN_Y              GENMASK_ULL(54, 53)
+#define     PKG_MAX_WIN_X              GENMASK_ULL(52, 48)
+
 #define CHV_CLK_CTL1                   _MMIO(0x101100)
 #define VLV_CLK_CTL2                   _MMIO(0x101104)
 #define   CLK_CTL2_CZCOUNT_30NS_SHIFT  28
diff --git a/drivers/gpu/drm/i915/intel_mchbar_regs.h 
b/drivers/gpu/drm/i915/intel_mchbar_regs.h
index 2aad2f0cc8db..4ba5f30b7901 100644
--- a/drivers/gpu/drm/i915/intel_mchbar_regs.h
+++ b/drivers/gpu/drm/i915/intel_mchbar_regs.h
@@ -189,6 +189,10 @@
 #define  DG1_QCLK_RATIO_MASK                   REG_GENMASK(9, 2)
 #define  DG1_QCLK_REFERENCE                    REG_BIT(10)
 
+#define PCU_PACKAGE_POWER_SKU_UNIT             _MMIO(MCHBAR_MIRROR_BASE_SNB + 
0x5938)
+#define   PKG_PWR_UNIT                         REG_GENMASK(3, 0)
+#define   PKG_TIME_UNIT                                REG_GENMASK(19, 16)
+
 #define GEN6_GT_PERF_STATUS                    _MMIO(MCHBAR_MIRROR_BASE_SNB + 
0x5948)
 #define GEN6_RP_STATE_LIMITS                   _MMIO(MCHBAR_MIRROR_BASE_SNB + 
0x5994)
 #define GEN6_RP_STATE_CAP                      _MMIO(MCHBAR_MIRROR_BASE_SNB + 
0x5998)
@@ -196,6 +200,9 @@
 #define   RP1_CAP_MASK                         REG_GENMASK(15, 8)
 #define   RPN_CAP_MASK                         REG_GENMASK(23, 16)
 
+#define PCU_PACKAGE_RAPL_LIMIT                 _MMIO(MCHBAR_MIRROR_BASE_SNB + 
0x59a0)
+#define   PKG_PWR_LIM_1                                REG_GENMASK(14, 0)
+
 /* snb MCH registers for priority tuning */
 #define MCH_SSKPD                              _MMIO(MCHBAR_MIRROR_BASE_SNB + 
0x5d10)
 #define   SSKPD_NEW_WM0_MASK_HSW               REG_GENMASK64(63, 56)
-- 
2.25.1

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