[PATCH] drm/xe/hwmon: Clamp power1_crit to GPU firmware default

[Karthik Poosa]

Clamp card critical power(power1_crit) to GPU firmware default
when value set by sysfs exceeds the maximum supported by pcode
mailbox.
Though pcode already does clamping, values above pcode mailbox
supported gets truncated resulting in incorrect critical power
getting set.
This patch avoids that truncation.

Signed-off-by: Karthik Poosa <karthik.poosa at intel.com>
Fixes: 92d44a422d0d ("drm/xe/hwmon: Expose card reactive critical power")
---
 drivers/gpu/drm/xe/xe_hwmon.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_hwmon.c b/drivers/gpu/drm/xe/xe_hwmon.c
index f08fc4377d25..ce239bc00ee4 100644
--- a/drivers/gpu/drm/xe/xe_hwmon.c
+++ b/drivers/gpu/drm/xe/xe_hwmon.c
@@ -137,7 +137,8 @@ struct xe_hwmon {
 	u32 pl1_on_boot[CHANNEL_MAX];
 	/** @pl2_on_boot: power limit PL2 on boot */
 	u32 pl2_on_boot[CHANNEL_MAX];
-
+	/** @psys_crit_on_boot: card critical power from GPU firmware */
+	u32 psys_crit_on_boot;
 };
 
 static int xe_hwmon_pcode_read_power_limit(const struct xe_hwmon *hwmon, u32 attr, int channel,
@@ -742,7 +743,16 @@ static int xe_hwmon_power_curr_crit_write(struct xe_hwmon *hwmon, int channel,
 
 	mutex_lock(&hwmon->hwmon_lock);
 
-	uval = DIV_ROUND_CLOSEST_ULL(value << POWER_SETUP_I1_SHIFT, scale_factor);
+	/* Maximum card critical power value supported by pcode mailbox. */
+#define MAX_CRIT_POWER_CURR 1023000000ull
+
+	if (value > MAX_CRIT_POWER_CURR) {
+		uval = hwmon->psys_crit_on_boot;
+		drm_info(&hwmon->xe->drm,
+			 "Clamping critical power to GPU firmware default 0x%x\n", uval);
+	} else {
+		uval = DIV_ROUND_CLOSEST_ULL(value << POWER_SETUP_I1_SHIFT, scale_factor);
+	}
 	ret = xe_hwmon_pcode_write_i1(hwmon, uval);
 
 	mutex_unlock(&hwmon->hwmon_lock);
@@ -1251,6 +1261,9 @@ xe_hwmon_get_preregistration_info(struct xe_hwmon *hwmon)
 			hwmon->scl_shift_time = REG_FIELD_GET(PKG_TIME_UNIT, val_sku_unit);
 		}
 	}
+	xe_hwmon_pcode_read_i1(hwmon, &hwmon->psys_crit_on_boot);
+	hwmon->psys_crit_on_boot &= POWER_SETUP_I1_DATA_MASK;
+
 	/*
 	 * Initialize 'struct xe_hwmon_energy_info', i.e. set fields to the
 	 * first value of the energy register read
-- 
2.25.1