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    <div class="moz-cite-prefix">On 02-05-2025 20:32, Nilawar, Badal
      wrote:<br>
    </div>
    <blockquote type="cite" cite="mid:ccb5e2f6-1e20-4430-bc63-f130b80a0ce2@intel.com">
      
      <p><br>
      </p>
      <div class="moz-cite-prefix">On 01-05-2025 02:06, Karthik Poosa
        wrote:<br>
      </div>
      <blockquote type="cite" cite="mid:20250430203607.926585-2-karthik.poosa@intel.com">
        <pre wrap="" class="moz-quote-pre">Add support to manage power limits using pcode mailbox commands
for supported platforms.</pre>
      </blockquote>
      Please add Fixes: tag here. </blockquote>
    <blockquote type="cite" cite="mid:ccb5e2f6-1e20-4430-bc63-f130b80a0ce2@intel.com">
      <blockquote type="cite" cite="mid:20250430203607.926585-2-karthik.poosa@intel.com">
        <pre wrap="" class="moz-quote-pre">Signed-off-by: Karthik Poosa <a class="moz-txt-link-rfc2396E" href="mailto:karthik.poosa@intel.com" moz-do-not-send="true"><karthik.poosa@intel.com></a>
---
 drivers/gpu/drm/xe/regs/xe_mchbar_regs.h |  10 +-
 drivers/gpu/drm/xe/xe_device_types.h     |   4 +
 drivers/gpu/drm/xe/xe_hwmon.c            | 348 ++++++++++++++++++-----
 drivers/gpu/drm/xe/xe_pci.c              |   5 +
 drivers/gpu/drm/xe/xe_pcode.c            |  11 +
 drivers/gpu/drm/xe/xe_pcode.h            |   3 +
 drivers/gpu/drm/xe/xe_pcode_api.h        |   7 +
 7 files changed, 307 insertions(+), 81 deletions(-)

diff --git a/drivers/gpu/drm/xe/regs/xe_mchbar_regs.h b/drivers/gpu/drm/xe/regs/xe_mchbar_regs.h
index f5e5234857c1..5394a1373a6b 100644
--- a/drivers/gpu/drm/xe/regs/xe_mchbar_regs.h
+++ b/drivers/gpu/drm/xe/regs/xe_mchbar_regs.h
@@ -38,10 +38,10 @@
 #define   TEMP_MASK                            REG_GENMASK(7, 0)
 
 #define PCU_CR_PACKAGE_RAPL_LIMIT              XE_REG(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)
+#define   PWR_LIM_VAL                          REG_GENMASK(14, 0)
+#define   PWR_LIM_EN                           REG_BIT(15)
+#define   PWR_LIM_TIME                         REG_GENMASK(23, 17)
+#define   PWR_LIM_TIME_X                       REG_GENMASK(23, 22)
+#define   PWR_LIM_TIME_Y                       REG_GENMASK(21, 17)
 
 #endif /* _XE_MCHBAR_REGS_H_ */
diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index 495bc00ebed4..2c8321eb41b9 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -326,6 +326,10 @@ struct xe_device {
                u8 has_heci_gscfi:1;
                /** @info.has_llc: Device has a shared CPU+GPU last level cache */
                u8 has_llc:1;
+               /** @info.has_mbx_power_limits: Device has support to manage power limits using
+                * pcode mailbox commands.
+                */
+               u8 has_mbx_power_limits:1;
                /** @info.has_pxp: Device has PXP support */
                u8 has_pxp:1;
                /** @info.has_range_tlb_invalidation: Has range based TLB invalidations */
diff --git a/drivers/gpu/drm/xe/xe_hwmon.c b/drivers/gpu/drm/xe/xe_hwmon.c
index eb293aec36a0..b906a1a058e0 100644
--- a/drivers/gpu/drm/xe/xe_hwmon.c
+++ b/drivers/gpu/drm/xe/xe_hwmon.c
@@ -51,6 +51,14 @@ enum xe_fan_channel {
        FAN_MAX,
 };
 
+/*
+ * For platforms that support mailbox commands for power limits, REG_PKG_POWER_SKU_UNIT is
+ * not supported and below are SKU units to be used.
+ */
+#define PWR_UNIT       0x3
+#define ENERGY_UNIT    0xe
+#define TIME_UNIT      0xa
+
 /*
  * SF_* - scale factors for particular quantities according to hwmon spec.
  */
@@ -60,6 +68,18 @@ enum xe_fan_channel {
 #define SF_ENERGY      1000000         /* microjoules */
 #define SF_TIME                1000            /* milliseconds */
 
+/*
+ * PL*_HWMON_ATTR - mapping of hardware power limits to corresponding hwmon power attribute.
+ */
+#define PL1_HWMON_ATTR hwmon_power_max
+
+#define PWR_ATTR_TO_STR(attr)  (((attr) == hwmon_power_max) ? "PL1" : "Invalid")
+
+/*
+ * Timeout for power limit write mailbox command.
+ */
+#define PL_WRITE_MBX_TIMEOUT_MS        (1)
+
 /**
  * struct xe_hwmon_energy_info - to accumulate energy
  */
@@ -100,8 +120,81 @@ struct xe_hwmon {
        struct xe_hwmon_energy_info ei[CHANNEL_MAX];
        /** @fi: Fan info for fanN_input */
        struct xe_hwmon_fan_info fi[FAN_MAX];
+       /** @boot_power_limit_read: is boot power limits read */
+       bool boot_power_limit_read;
+       /** pl1_on_boot: power limit PL1 on boot */
+       u32 pl1_on_boot[CHANNEL_MAX];
 };
 
+static int xe_hwmon_pcode_read_power_limit(const struct xe_hwmon *hwmon, u32 attr, int channel,
+                                          u32 *uval)
+{
+       struct xe_tile *root_tile = xe_device_get_root_tile(hwmon->xe);
+       u32 val0 = 0, val1 = 0;
+       int ret = 0;
+
+       ret = xe_pcode_read(root_tile, PCODE_MBOX(PCODE_POWER_SETUP,
+                                                 (channel == CHANNEL_CARD) ?
+                                                 READ_PSYSGPU_POWER_LIMIT :
+                                                 READ_PACKAGE_POWER_LIMIT,
+                                                 hwmon->boot_power_limit_read ?
+                                                 READ_PL_FROM_PCODE : READ_PL_FROM_BIOS),
+                                                 &val0, &val1);
+
+       if (ret) {
+               drm_dbg(&hwmon->xe->drm, "read failed ch %d val0 0x%08x, val1 0x%08x, ret %d\n",
+                       channel, val0, val1, ret);
+               *uval = 0;
+               return ret;
+       }
+
+       /* return the value only if limit is enabled */
+       if (attr == PL1_HWMON_ATTR)
+               *uval = (val0 & PWR_LIM_EN) ? val0 : 0;
+       else if (attr == hwmon_power_label)
+               *uval = (val0 & PWR_LIM_EN) ? 1 : (val1 & PWR_LIM_EN) ? 1 : 0;
+       else
+               *uval = 0;
+
+       return ret;
+}
+
+static int xe_hwmon_pcode_write_power_limit(const struct xe_hwmon *hwmon, u32 attr, u8 channel,
+                                           u32 uval)
+{
+       struct xe_tile *root_tile = xe_device_get_root_tile(hwmon->xe);
+       u32 val0, val1;
+       int ret = 0;
+
+       ret = xe_pcode_read(root_tile, PCODE_MBOX(PCODE_POWER_SETUP,
+                                                 (channel == CHANNEL_CARD) ?
+                                                 READ_PSYSGPU_POWER_LIMIT :
+                                                 READ_PACKAGE_POWER_LIMIT,
+                                                 hwmon->boot_power_limit_read ?
+                                                 READ_PL_FROM_PCODE : READ_PL_FROM_BIOS),
+                                                 &val0, &val1);
+
+       if (ret)
+               drm_dbg(&hwmon->xe->drm, "read failed ch %d val0 0x%08x, val1 0x%08x, ret %d\n",
+                       channel, val0, val1, ret);
+
+       if (attr == PL1_HWMON_ATTR)
+               val0 = uval;
+       else
+               return -EIO;
+
+       drm_dbg(&hwmon->xe->drm, "writing limit val %x channel %d\n", uval, channel);
+       ret = xe_pcode_write64_timeout(root_tile, PCODE_MBOX(PCODE_POWER_SETUP,
+                                                            (channel == CHANNEL_CARD) ?
+                                                            WRITE_PSYSGPU_POWER_LIMIT :
+                                                            WRITE_PACKAGE_POWER_LIMIT, 1),</pre>
      </blockquote>
      Any specific reason to use param2=1? In mbx doc I don't see param2
      is needed for power limit write. </blockquote>
    <p>This can be removed, it is valid only for read.</p>
    <blockquote type="cite" cite="mid:ccb5e2f6-1e20-4430-bc63-f130b80a0ce2@intel.com">
      <blockquote type="cite" cite="mid:20250430203607.926585-2-karthik.poosa@intel.com">
        <pre wrap="" class="moz-quote-pre">+                                                       val0, val1, PL_WRITE_MBX_TIMEOUT_MS);
+       if (ret)
+               drm_dbg(&hwmon->xe->drm, "write failed ch %d val0 0x%08x, val1 0x%08x, ret %d\n",
+                       channel, val0, val1, ret);
+       return ret;
+}
+
 static struct xe_reg xe_hwmon_get_reg(struct xe_hwmon *hwmon, enum xe_hwmon_reg hwmon_reg,
                                      int channel)
 {
@@ -181,7 +274,7 @@ static struct xe_reg xe_hwmon_get_reg(struct xe_hwmon *hwmon, enum xe_hwmon_reg
        return XE_REG(0);
 }
 
-#define PL1_DISABLE 0
+#define PL_DISABLE 0
 
 /*
  * HW allows arbitrary PL1 limits to be set but silently clamps these values to
@@ -189,67 +282,87 @@ static struct xe_reg xe_hwmon_get_reg(struct xe_hwmon *hwmon, enum xe_hwmon_reg
  * same pattern for sysfs, allow arbitrary PL1 limits to be set but display
  * clamped values when read.
  */
-static void xe_hwmon_power_max_read(struct xe_hwmon *hwmon, int channel, long *value)
+static void xe_hwmon_power_max_read(struct xe_hwmon *hwmon, u32 attr, int channel, long *value)
 {
        u64 reg_val, min, max;
        struct xe_device *xe = hwmon->xe;
        struct xe_reg rapl_limit, pkg_power_sku;
        struct xe_mmio *mmio = xe_root_tile_mmio(xe);
 
-       rapl_limit = xe_hwmon_get_reg(hwmon, REG_PKG_RAPL_LIMIT, channel);
-       pkg_power_sku = xe_hwmon_get_reg(hwmon, REG_PKG_POWER_SKU, channel);
+       mutex_lock(&hwmon->hwmon_lock);
 
-       /*
-        * Valid check of REG_PKG_RAPL_LIMIT is already done in xe_hwmon_power_is_visible.
-        * So not checking it again here.
-        */
-       if (!xe_reg_is_valid(pkg_power_sku)) {
-               drm_warn(&xe->drm, "pkg_power_sku invalid\n");
-               *value = 0;
-               return;
+       if (hwmon->xe->info.has_mbx_power_limits) {
+               xe_hwmon_pcode_read_power_limit(hwmon, attr, channel, (u32 *)&reg_val);
+       } else {
+               rapl_limit = xe_hwmon_get_reg(hwmon, REG_PKG_RAPL_LIMIT, channel);
+               pkg_power_sku = xe_hwmon_get_reg(hwmon, REG_PKG_POWER_SKU, channel);
+
+               /*
+                * Valid check of REG_PKG_RAPL_LIMIT is already done in xe_hwmon_power_is_visible.
+                * So not checking it again here.
+                */
+               if (!xe_reg_is_valid(pkg_power_sku)) {
+                       drm_warn(&xe->drm, "pkg_power_sku invalid\n");
+                       *value = 0;
+                       goto unlock;
+               }
+               reg_val = xe_mmio_read32(mmio, rapl_limit);
        }
 
-       mutex_lock(&hwmon->hwmon_lock);
-
-       reg_val = xe_mmio_read32(mmio, rapl_limit);
-       /* Check if PL1 limit is disabled */
-       if (!(reg_val & PKG_PWR_LIM_1_EN)) {
-               *value = PL1_DISABLE;
+       /* Check if PL limits are disabled */
+       if (!(reg_val & PWR_LIM_EN)) {
+               *value = PL_DISABLE;
+               drm_warn(&hwmon->xe->drm, "%s disabled for channel %d !, val 0x%016llx\n",
+                        PWR_ATTR_TO_STR(attr), channel, reg_val);
                goto unlock;
        }
 
-       reg_val = REG_FIELD_GET(PKG_PWR_LIM_1, reg_val);
+       reg_val = REG_FIELD_GET(PWR_LIM_VAL, reg_val);
        *value = mul_u64_u32_shr(reg_val, SF_POWER, hwmon->scl_shift_power);
 
-       reg_val = xe_mmio_read64_2x32(mmio, pkg_power_sku);
-       min = REG_FIELD_GET(PKG_MIN_PWR, reg_val);
+       if (hwmon->xe->info.has_mbx_power_limits) {
+               /* No MIN_PWR defined, using boot PL1 as max */
+               min = 0;</pre>
      </blockquote>
      <p>In my opinion, the pcode clips the values according to the BIOS
        settings, so should we simply  return value provided by the
        pcode?</p>
    </blockquote>
    <p>I shall check on this.</p>
    <blockquote type="cite" cite="mid:ccb5e2f6-1e20-4430-bc63-f130b80a0ce2@intel.com">
      <blockquote type="cite" cite="mid:20250430203607.926585-2-karthik.poosa@intel.com">
        <pre wrap="" class="moz-quote-pre">+          max = hwmon->pl1_on_boot[channel] & PWR_LIM_VAL;
+       } else {
+               reg_val = xe_mmio_read64_2x32(mmio, pkg_power_sku);
+               min = REG_FIELD_GET(PKG_MIN_PWR, reg_val);
+               max = REG_FIELD_GET(PKG_MAX_PWR, reg_val);
+       }
+
        min = mul_u64_u32_shr(min, SF_POWER, hwmon->scl_shift_power);
-       max = REG_FIELD_GET(PKG_MAX_PWR, reg_val);
        max = mul_u64_u32_shr(max, SF_POWER, hwmon->scl_shift_power);
-
        if (min && max)
                *value = clamp_t(u64, *value, min, max);
 unlock:
        mutex_unlock(&hwmon->hwmon_lock);
 }
 
-static int xe_hwmon_power_max_write(struct xe_hwmon *hwmon, int channel, long value)
+static int xe_hwmon_power_max_write(struct xe_hwmon *hwmon, u32 attr, int channel, long value)
 {
        struct xe_mmio *mmio = xe_root_tile_mmio(hwmon->xe);
        int ret = 0;
-       u64 reg_val;
+       u32 reg_val;
        struct xe_reg rapl_limit;
 
+       mutex_lock(&hwmon->hwmon_lock);
+
        rapl_limit = xe_hwmon_get_reg(hwmon, REG_PKG_RAPL_LIMIT, channel);
 
-       mutex_lock(&hwmon->hwmon_lock);
+       /* Disable Power Limit and verify, as limit cannot be disabled on all platforms */
+       if (value == PL_DISABLE) {
+               if (hwmon->xe->info.has_mbx_power_limits) {
+                       drm_dbg(&hwmon->xe->drm, "disabling %s on channel %d\n",
+                               PWR_ATTR_TO_STR(attr), channel);
+                       xe_hwmon_pcode_write_power_limit(hwmon, attr, channel, 0);
+                       xe_hwmon_pcode_read_power_limit(hwmon, attr, channel, &reg_val);
+               } else {
+                       reg_val = xe_mmio_rmw32(mmio, rapl_limit, PWR_LIM_EN, 0);
+                       reg_val = xe_mmio_read32(mmio, rapl_limit);
+               }
 
-       /* Disable PL1 limit and verify, as limit cannot be disabled on all platforms */
-       if (value == PL1_DISABLE) {
-               reg_val = xe_mmio_rmw32(mmio, rapl_limit, PKG_PWR_LIM_1_EN, 0);
-               reg_val = xe_mmio_read32(mmio, rapl_limit);
-               if (reg_val & PKG_PWR_LIM_1_EN) {
-                       drm_warn(&hwmon->xe->drm, "PL1 disable is not supported!\n");
+               if (reg_val & PWR_LIM_EN) {
+                       drm_warn(&hwmon->xe->drm, "Power limit disable is not supported!\n");
                        ret = -EOPNOTSUPP;
                }
                goto unlock;
@@ -257,26 +370,38 @@ static int xe_hwmon_power_max_write(struct xe_hwmon *hwmon, int channel, long va
 
        /* Computation in 64-bits to avoid overflow. Round to nearest. */
        reg_val = DIV_ROUND_CLOSEST_ULL((u64)value << hwmon->scl_shift_power, SF_POWER);
-       reg_val = PKG_PWR_LIM_1_EN | REG_FIELD_PREP(PKG_PWR_LIM_1, reg_val);
-       reg_val = xe_mmio_rmw32(mmio, rapl_limit, PKG_PWR_LIM_1_EN | PKG_PWR_LIM_1, reg_val);
+       reg_val = PWR_LIM_EN | REG_FIELD_PREP(PWR_LIM_VAL, reg_val);
 
+       if (hwmon->xe->info.has_mbx_power_limits)
+               ret = xe_hwmon_pcode_write_power_limit(hwmon, attr, channel, reg_val);
+       else
+               reg_val = xe_mmio_rmw32(mmio, rapl_limit, PWR_LIM_EN | PWR_LIM_VAL,
+                                       reg_val);
 unlock:
        mutex_unlock(&hwmon->hwmon_lock);
        return ret;
 }
 
-static void xe_hwmon_power_rated_max_read(struct xe_hwmon *hwmon, int channel, long *value)
+static void xe_hwmon_power_rated_max_read(struct xe_hwmon *hwmon, u32 attr, int channel,
+                                         long *value)
 {
        struct xe_mmio *mmio = xe_root_tile_mmio(hwmon->xe);
-       struct xe_reg reg = xe_hwmon_get_reg(hwmon, REG_PKG_POWER_SKU, channel);
-       u64 reg_val;
+       u32 reg_val;
+
+       if (hwmon->xe->info.has_mbx_power_limits) {
+               /* PL1 is rated max if supported */
+               xe_hwmon_pcode_read_power_limit(hwmon, PL1_HWMON_ATTR, channel, &reg_val);
+       } else {
+               /*
+                * This sysfs file won't be visible if REG_PKG_POWER_SKU is invalid, so valid check
+                * for this register can be skipped.
+                * See xe_hwmon_power_is_visible.
+                */
+               struct xe_reg reg = xe_hwmon_get_reg(hwmon, REG_PKG_POWER_SKU, channel);
+
+               reg_val = xe_mmio_read32(mmio, reg);
+       }
 
-       /*
-        * This sysfs file won't be visible if REG_PKG_POWER_SKU is invalid, so valid check
-        * for this register can be skipped.
-        * See xe_hwmon_power_is_visible.
-        */
-       reg_val = xe_mmio_read32(mmio, reg);
        reg_val = REG_FIELD_GET(PKG_TDP, reg_val);</pre>
      </blockquote>
      <blockquote type="cite" cite="mid:20250430203607.926585-2-karthik.poosa@intel.com">
        <pre wrap="" class="moz-quote-pre">   *value = mul_u64_u32_shr(reg_val, SF_POWER, hwmon->scl_shift_power);
 }
@@ -330,20 +455,32 @@ xe_hwmon_power_max_interval_show(struct device *dev, struct device_attribute *at
        struct xe_mmio *mmio = xe_root_tile_mmio(hwmon->xe);
        u32 x, y, x_w = 2; /* 2 bits */
        u64 r, tau4, out;
-       int sensor_index = to_sensor_dev_attr(attr)->index;
+       int channel = to_sensor_dev_attr(attr)->index;
+       u32 power_attr = PL1_HWMON_ATTR;
+       int ret = 0;
 
        xe_pm_runtime_get(hwmon->xe);
 
        mutex_lock(&hwmon->hwmon_lock);
 
-       r = xe_mmio_read32(mmio, xe_hwmon_get_reg(hwmon, REG_PKG_RAPL_LIMIT, sensor_index));
+       if (hwmon->xe->info.has_mbx_power_limits) {
+               ret = xe_hwmon_pcode_read_power_limit(hwmon, power_attr, channel, (u32 *)&r);
+               if (ret) {
+                       drm_err(&hwmon->xe->drm,
+                               "power interval read fail, ch %d, attr %d, r 0%llx, ret %d\n",
+                               channel, power_attr, r, ret);
+                       r = 0;
+               }
+       } else {
+               r = xe_mmio_read32(mmio, xe_hwmon_get_reg(hwmon, REG_PKG_RAPL_LIMIT, channel));
+       }
 
        mutex_unlock(&hwmon->hwmon_lock);
 
        xe_pm_runtime_put(hwmon->xe);
 
-       x = REG_FIELD_GET(PKG_PWR_LIM_1_TIME_X, r);
-       y = REG_FIELD_GET(PKG_PWR_LIM_1_TIME_Y, r);
+       x = REG_FIELD_GET(PWR_LIM_TIME_X, r);
+       y = REG_FIELD_GET(PWR_LIM_TIME_Y, r);
 
        /*
         * tau = 1.x * power(2,y), x = bits(23:22), y = bits(21:17)
@@ -373,12 +510,16 @@ xe_hwmon_power_max_interval_store(struct device *dev, struct device_attribute *a
        u64 tau4, r, max_win;
        unsigned long val;
        int ret;
-       int sensor_index = to_sensor_dev_attr(attr)->index;
+       int channel = to_sensor_dev_attr(attr)->index;
+       u32 power_attr = PL1_HWMON_ATTR;
 
        ret = kstrtoul(buf, 0, &val);
        if (ret)
                return ret;
 
+       drm_dbg(&hwmon->xe->drm, "power_max_interval store ch %d, attr %s val 0x%lx\n", channel,
+               PWR_ATTR_TO_STR(power_attr), val);
+
        /*
         * Max HW supported tau in '1.x * power(2,y)' format, x = 0, y = 0x12.
         * The hwmon->scl_shift_time default of 0xa results in a max tau of 256 seconds.
@@ -400,8 +541,10 @@ xe_hwmon_power_max_interval_store(struct device *dev, struct device_attribute *a
        tau4 = (u64)((1 << x_w) | x) << y;
        max_win = mul_u64_u32_shr(tau4, SF_TIME, hwmon->scl_shift_time + x_w);
 
-       if (val > max_win)
+       if (val > max_win) {
+               drm_warn(&hwmon->xe->drm, "power_interval invalid val 0x%lx\n", val);
                return -EINVAL;
+       }
 
        /* val in hw units */
        val = DIV_ROUND_CLOSEST_ULL((u64)val << hwmon->scl_shift_time, SF_TIME);
@@ -419,14 +562,22 @@ xe_hwmon_power_max_interval_store(struct device *dev, struct device_attribute *a
                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);
+       rxy = REG_FIELD_PREP(PWR_LIM_TIME_X, x) |
+                              REG_FIELD_PREP(PWR_LIM_TIME_Y, y);
 
        xe_pm_runtime_get(hwmon->xe);
 
        mutex_lock(&hwmon->hwmon_lock);
 
-       r = xe_mmio_rmw32(mmio, xe_hwmon_get_reg(hwmon, REG_PKG_RAPL_LIMIT, sensor_index),
-                         PKG_PWR_LIM_1_TIME, rxy);
+       if (hwmon->xe->info.has_mbx_power_limits) {
+               ret = xe_hwmon_pcode_read_power_limit(hwmon, power_attr, channel, (u32 *)&r);
+               r = (r & ~PWR_LIM_TIME) | rxy;
+               drm_dbg(&hwmon->xe->drm, "power_max_interval store ch %d rxy 0x%x\n", channel, rxy);
+               xe_hwmon_pcode_write_power_limit(hwmon, power_attr, channel, r);
+       } else {
+               r = xe_mmio_rmw32(mmio, xe_hwmon_get_reg(hwmon, REG_PKG_RAPL_LIMIT, channel),
+                                 PWR_LIM_TIME, rxy);
+       }
 
        mutex_unlock(&hwmon->hwmon_lock);
 
@@ -435,6 +586,7 @@ xe_hwmon_power_max_interval_store(struct device *dev, struct device_attribute *a
        return count;
 }
 
+/* PSYS PL1 */
 static SENSOR_DEVICE_ATTR(power1_max_interval, 0664,
                          xe_hwmon_power_max_interval_show,
                          xe_hwmon_power_max_interval_store, CHANNEL_CARD);
@@ -455,10 +607,19 @@ static umode_t xe_hwmon_attributes_visible(struct kobject *kobj,
        struct device *dev = kobj_to_dev(kobj);
        struct xe_hwmon *hwmon = dev_get_drvdata(dev);
        int ret = 0;
+       int channel = index ? CHANNEL_PKG : CHANNEL_CARD;
+       u32 power_attr = PL1_HWMON_ATTR;
+       u32 uval;
 
        xe_pm_runtime_get(hwmon->xe);
 
-       ret = xe_reg_is_valid(xe_hwmon_get_reg(hwmon, REG_PKG_RAPL_LIMIT, index)) ? attr->mode : 0;
+       if (hwmon->xe->info.has_mbx_power_limits) {
+               xe_hwmon_pcode_read_power_limit(hwmon, power_attr, channel, &uval);
+               ret = (uval & PWR_LIM_EN) ? attr->mode : 0;
+       } else {
+               ret = xe_reg_is_valid(xe_hwmon_get_reg(hwmon, REG_PKG_RAPL_LIMIT,
+                                                      channel)) ? attr->mode : 0;
+       }
 
        xe_pm_runtime_put(hwmon->xe);
 
@@ -604,19 +765,27 @@ xe_hwmon_power_is_visible(struct xe_hwmon *hwmon, u32 attr, int channel)
 
        switch (attr) {
        case hwmon_power_max:
-               return xe_reg_is_valid(xe_hwmon_get_reg(hwmon, REG_PKG_RAPL_LIMIT,
+               if (hwmon->xe->info.has_mbx_power_limits) {
+                       xe_hwmon_pcode_read_power_limit(hwmon, attr, channel, &uval);
+                       return (uval) ? (attr == hwmon_power_label) ? 0444 : 0664 : 0;</pre>
      </blockquote>
      In this code block this check is unnecessary. <br>
    </blockquote>
    yes, will remove it.
    <blockquote type="cite" cite="mid:ccb5e2f6-1e20-4430-bc63-f130b80a0ce2@intel.com">
      <blockquote type="cite" cite="mid:20250430203607.926585-2-karthik.poosa@intel.com">
        <pre wrap="" class="moz-quote-pre">+          } else {
+                       return xe_reg_is_valid(xe_hwmon_get_reg(hwmon, REG_PKG_RAPL_LIMIT,
                                       channel)) ? 0664 : 0;
+               }
        case hwmon_power_rated_max:
-               return xe_reg_is_valid(xe_hwmon_get_reg(hwmon, REG_PKG_POWER_SKU,
-                                      channel)) ? 0444 : 0;
+               if (hwmon->xe->info.has_mbx_power_limits)
+                       return 0;
+               else
+                       return xe_reg_is_valid(xe_hwmon_get_reg(hwmon, REG_PKG_POWER_SKU,
+                                              channel)) ? 0444 : 0;
        case hwmon_power_crit:
-               if (channel == CHANNEL_PKG)
-                       return (xe_hwmon_pcode_read_i1(hwmon, &uval) ||
-                               !(uval & POWER_SETUP_I1_WATTS)) ? 0 : 0644;
-               break;
        case hwmon_power_label:
-               return xe_reg_is_valid(xe_hwmon_get_reg(hwmon, REG_PKG_POWER_SKU_UNIT,
-                                      channel)) ? 0444 : 0;
+               if (channel == CHANNEL_PKG) {
+                       xe_hwmon_pcode_read_i1(hwmon, &uval);
+                       return (uval & POWER_SETUP_I1_WATTS) ? (attr == hwmon_power_label) ?
+                               0444 : 0644 : 0;</pre>
      </blockquote>
      In this code block this check is unnecessary. </blockquote>
    <p>Here it is needed, because case defintion is same <span style="white-space: pre-wrap">hwmon_power_crit</span> and <span style="white-space: pre-wrap">hwmon_power_label</span></p>
    <p>and for case for label we dont have write permission.</p>
    <blockquote type="cite" cite="mid:ccb5e2f6-1e20-4430-bc63-f130b80a0ce2@intel.com">
      <blockquote type="cite" cite="mid:20250430203607.926585-2-karthik.poosa@intel.com">
        <pre wrap="" class="moz-quote-pre">+          }
+               break;
        default:
                return 0;
        }
@@ -628,10 +797,10 @@ xe_hwmon_power_read(struct xe_hwmon *hwmon, u32 attr, int channel, long *val)
 {
        switch (attr) {
        case hwmon_power_max:
-               xe_hwmon_power_max_read(hwmon, channel, val);
+               xe_hwmon_power_max_read(hwmon, attr, channel, val);
                return 0;
        case hwmon_power_rated_max:
-               xe_hwmon_power_rated_max_read(hwmon, channel, val);
+               xe_hwmon_power_rated_max_read(hwmon, attr, channel, val);
                return 0;
        case hwmon_power_crit:
                return xe_hwmon_power_curr_crit_read(hwmon, channel, val, SF_POWER);
@@ -645,7 +814,7 @@ xe_hwmon_power_write(struct xe_hwmon *hwmon, u32 attr, int channel, long val)
 {
        switch (attr) {
        case hwmon_power_max:
-               return xe_hwmon_power_max_write(hwmon, channel, val);
+               return xe_hwmon_power_max_write(hwmon, attr, channel, val);
        case hwmon_power_crit:
                return xe_hwmon_power_curr_crit_write(hwmon, channel, val, SF_POWER);
        default:
@@ -965,18 +1134,45 @@ xe_hwmon_get_preregistration_info(struct xe_hwmon *hwmon)
        int channel;
        struct xe_reg pkg_power_sku_unit;
 
-       /*
-        * The contents of register PKG_POWER_SKU_UNIT do not change,
-        * so read it once and store the shift values.
-        */
-       pkg_power_sku_unit = xe_hwmon_get_reg(hwmon, REG_PKG_POWER_SKU_UNIT, 0);
-       if (xe_reg_is_valid(pkg_power_sku_unit)) {
-               val_sku_unit = xe_mmio_read32(mmio, pkg_power_sku_unit);
-               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);
+       if (hwmon->xe->info.has_mbx_power_limits) {
+               /* Check if mailbox power limits commands are supported by the firmware */
+               if (!xe_hwmon_pcode_read_power_limit(hwmon, PL1_HWMON_ATTR, CHANNEL_CARD,
+                                                    &hwmon->pl1_on_boot[CHANNEL_CARD])) {
+                       /* Read all default power limits */
+                       if (xe_hwmon_pcode_read_power_limit(hwmon, PL1_HWMON_ATTR, CHANNEL_PKG,
+                                                           &hwmon->pl1_on_boot[CHANNEL_PKG])) {
+                               drm_warn(&hwmon->xe->drm, "Failed to read pkg power limit\n");
+                       } else {
+                               /* Write default limits to read from pcode from now on */
+                               xe_hwmon_pcode_write_power_limit(hwmon, PL1_HWMON_ATTR,
+                                                                CHANNEL_CARD,
+                                                                hwmon->pl1_on_boot[CHANNEL_CARD]);
+                               xe_hwmon_pcode_write_power_limit(hwmon, PL1_HWMON_ATTR, CHANNEL_PKG,
+                                                                hwmon->pl1_on_boot[CHANNEL_PKG]);
+
+                               hwmon->scl_shift_power = PWR_UNIT;
+                               hwmon->scl_shift_energy = ENERGY_UNIT;
+                               hwmon->scl_shift_time = TIME_UNIT;
+                               drm_info(&hwmon->xe->drm, "Using mailbox commands for power limits\n");
+                               hwmon->boot_power_limit_read = true;
+                       }
+               } else {
+                       drm_warn(&hwmon->xe->drm, "Failed to read power limits, check firmware !\n");</pre>
      </blockquote>
      s/check firmware/check card firmware/ ?
      <blockquote type="cite" cite="mid:20250430203607.926585-2-karthik.poosa@intel.com">
        <pre wrap="" class="moz-quote-pre">+          }</pre>
      </blockquote>
      <p>Could you please simplify this if else block. <br>
      </p>
      <pre wrap="" class="moz-quote-pre">     if (xe_hwmon_pcode_read_power_limit(hwmon, PL1_HWMON_ATTR, CHANNEL_CARD,
                                             &hwmon->pl1_on_boot[CHANNEL_CARD])) {
                drm_warn;
                return;
        <span style="white-space: normal"> }
</span>   if (xe_hwmon_pcode_read_power_limit(hwmon, PL1_HWMON_ATTR, CHANNEL_PKG,
                                             &hwmon->pl1_on_boot[CHANNEL_PKG])) {
                drm_warn;
                return;
        <span style="white-space: normal"> }</span>
</pre>
      <pre wrap="" class="moz-quote-pre">         update default values.

Regards,
Badal</pre>
    </blockquote>
    <blockquote type="cite" cite="mid:ccb5e2f6-1e20-4430-bc63-f130b80a0ce2@intel.com">
      <blockquote type="cite" cite="mid:20250430203607.926585-2-karthik.poosa@intel.com">
        <pre wrap="" class="moz-quote-pre">+  } else {
+               drm_info(&hwmon->xe->drm, "Using register for power limits\n");
+               /*
+                * The contents of register PKG_POWER_SKU_UNIT do not change,
+                * so read it once and store the shift values.
+                */
+               pkg_power_sku_unit = xe_hwmon_get_reg(hwmon, REG_PKG_POWER_SKU_UNIT, 0);
+               if (xe_reg_is_valid(pkg_power_sku_unit)) {
+                       val_sku_unit = xe_mmio_read32(mmio, pkg_power_sku_unit);
+                       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 xe_hwmon_energy_info', i.e. set fields to the
         * first value of the energy register read
diff --git a/drivers/gpu/drm/xe/xe_pci.c b/drivers/gpu/drm/xe/xe_pci.c
index 882398e09b7e..95a2a458e8f7 100644
--- a/drivers/gpu/drm/xe/xe_pci.c
+++ b/drivers/gpu/drm/xe/xe_pci.c
@@ -66,6 +66,7 @@ struct xe_device_desc {
        u8 has_heci_gscfi:1;
        u8 has_heci_cscfi:1;
        u8 has_llc:1;
+       u8 has_mbx_power_limits:1;
        u8 has_pxp:1;
        u8 has_sriov:1;
        u8 needs_scratch:1;
@@ -305,6 +306,7 @@ static const struct xe_device_desc dg2_desc = {
        DG2_FEATURES,
        .has_display = true,
        .has_fan_control = true,
+       .has_mbx_power_limits = false,
 };
 
 static const __maybe_unused struct xe_device_desc pvc_desc = {
@@ -316,6 +318,7 @@ static const __maybe_unused struct xe_device_desc pvc_desc = {
        .has_heci_gscfi = 1,
        .max_remote_tiles = 1,
        .require_force_probe = true,
+       .has_mbx_power_limits = false,
 };
 
 static const struct xe_device_desc mtl_desc = {
@@ -341,6 +344,7 @@ static const struct xe_device_desc bmg_desc = {
        .dma_mask_size = 46,
        .has_display = true,
        .has_fan_control = true,
+       .has_mbx_power_limits = true,
        .has_heci_cscfi = 1,
        .needs_scratch = true,
 };
@@ -583,6 +587,7 @@ static int xe_info_init_early(struct xe_device *xe,
        xe->info.dma_mask_size = desc->dma_mask_size;
        xe->info.is_dgfx = desc->is_dgfx;
        xe->info.has_fan_control = desc->has_fan_control;
+       xe->info.has_mbx_power_limits = desc->has_mbx_power_limits;
        xe->info.has_heci_gscfi = desc->has_heci_gscfi;
        xe->info.has_heci_cscfi = desc->has_heci_cscfi;
        xe->info.has_llc = desc->has_llc;
diff --git a/drivers/gpu/drm/xe/xe_pcode.c b/drivers/gpu/drm/xe/xe_pcode.c
index cf955b3ed52c..9189117fe825 100644
--- a/drivers/gpu/drm/xe/xe_pcode.c
+++ b/drivers/gpu/drm/xe/xe_pcode.c
@@ -109,6 +109,17 @@ int xe_pcode_write_timeout(struct xe_tile *tile, u32 mbox, u32 data, int timeout
        return err;
 }
 
+int xe_pcode_write64_timeout(struct xe_tile *tile, u32 mbox, u32 data0, u32 data1, int timeout)
+{
+       int err;
+
+       mutex_lock(&tile->pcode.lock);
+       err = pcode_mailbox_rw(tile, mbox, &data0, &data1, timeout, false, false);
+       mutex_unlock(&tile->pcode.lock);
+
+       return err;
+}
+
 int xe_pcode_read(struct xe_tile *tile, u32 mbox, u32 *val, u32 *val1)
 {
        int err;
diff --git a/drivers/gpu/drm/xe/xe_pcode.h b/drivers/gpu/drm/xe/xe_pcode.h
index ba33991d72a7..de38f44f3201 100644
--- a/drivers/gpu/drm/xe/xe_pcode.h
+++ b/drivers/gpu/drm/xe/xe_pcode.h
@@ -18,6 +18,9 @@ int xe_pcode_init_min_freq_table(struct xe_tile *tile, u32 min_gt_freq,
 int xe_pcode_read(struct xe_tile *tile, u32 mbox, u32 *val, u32 *val1);
 int xe_pcode_write_timeout(struct xe_tile *tile, u32 mbox, u32 val,
                           int timeout_ms);
+int xe_pcode_write64_timeout(struct xe_tile *tile, u32 mbox, u32 data0,
+                            u32 data1, int timeout);
+
 #define xe_pcode_write(tile, mbox, val) \
        xe_pcode_write_timeout(tile, mbox, val, 1)
 
diff --git a/drivers/gpu/drm/xe/xe_pcode_api.h b/drivers/gpu/drm/xe/xe_pcode_api.h
index e622ae17f08d..8c8be7c5f47b 100644
--- a/drivers/gpu/drm/xe/xe_pcode_api.h
+++ b/drivers/gpu/drm/xe/xe_pcode_api.h
@@ -42,6 +42,13 @@
 #define            POWER_SETUP_I1_SHIFT                6       /* 10.6 fixed point format */
 #define            POWER_SETUP_I1_DATA_MASK            REG_GENMASK(15, 0)
 
+#define        READ_PSYSGPU_POWER_LIMIT                0x6
+#define        WRITE_PSYSGPU_POWER_LIMIT               0x7
+#define        READ_PACKAGE_POWER_LIMIT                0x8
+#define        WRITE_PACKAGE_POWER_LIMIT               0x9
+#define        READ_PL_FROM_BIOS                       0x1
+#define        READ_PL_FROM_PCODE                      0x0
+
 #define   PCODE_FREQUENCY_CONFIG               0x6e
 /* Frequency Config Sub Commands (param1) */
 #define     PCODE_MBOX_FC_SC_READ_FUSED_P0     0x0
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