[SRU][P:linux][PATCH v2 8/8] drm/xe/hwmon: Fix xe_hwmon_power_max_write
Thibault Ferrante
thibault.ferrante at canonical.com
Thu Sep 11 07:58:37 UTC 2025
From: Karthik Poosa <karthik.poosa at intel.com>
BugLink: https://bugs.launchpad.net/bugs/2122435
Prevent other bits of mailbox power limit from being overwritten with 0.
This issue was due to a missing read and modify of current power limit,
before setting a requested mailbox power limit, which is added in this
patch.
v2:
- Improve commit message. (Anshuman)
v3:
- Rebase.
- Rephrase commit message. (Riana)
- Add read-modify-write variant of xe_hwmon_pcode_write_power_limit()
i.e. xe_hwmon_pcode_rmw_power_limit(). (Badal)
- Use xe_hwmon_pcode_rmw_power_limit() to set mailbox power limits.
- Remove xe_hwmon_pcode_write_power_limit() as all mailbox power limits
writes use xe_hwmon_pcode_rmw_power_limit() only.
v4:
- Use PWR_LIM in place of (PWR_LIM_EN | PWR_LIM_VAL) wherever
applicable. (Riana)
Fixes: 7596d839f6228 ("drm/xe/hwmon: Add support to manage power limits though mailbox")
Reviewed-by: Riana Tauro <riana.tauro at intel.com>
Signed-off-by: Karthik Poosa <karthik.poosa at intel.com>
Reviewed-by: Badal Nilawar <badal.nilawar at intel.com>
Link: https://lore.kernel.org/r/20250617120030.612819-1-karthik.poosa@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
(cherry picked from commit 8aa7306631f088881759398972d503757cf0c901)
Signed-off-by: Bommu Krishnaiah <krishnaiah.bommu at intel.com>
Signed-off-by: Thibault Ferrante <thibault.ferrante at canonical.com>
---
drivers/gpu/drm/xe/regs/xe_mchbar_regs.h | 1 +
drivers/gpu/drm/xe/xe_hwmon.c | 50 +++++++++++-------------
2 files changed, 24 insertions(+), 27 deletions(-)
diff --git a/drivers/gpu/drm/xe/regs/xe_mchbar_regs.h b/drivers/gpu/drm/xe/regs/xe_mchbar_regs.h
index 5e8ce7bf78d3..2fb4b61544bc 100644
--- a/drivers/gpu/drm/xe/regs/xe_mchbar_regs.h
+++ b/drivers/gpu/drm/xe/regs/xe_mchbar_regs.h
@@ -37,6 +37,7 @@
#define PCU_CR_PACKAGE_RAPL_LIMIT XE_REG(MCHBAR_MIRROR_BASE_SNB + 0x59a0)
#define PWR_LIM_VAL REG_GENMASK(14, 0)
#define PWR_LIM_EN REG_BIT(15)
+#define PWR_LIM REG_GENMASK(15, 0)
#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)
diff --git a/drivers/gpu/drm/xe/xe_hwmon.c b/drivers/gpu/drm/xe/xe_hwmon.c
index 4212b1a4a392..ad79843c1b58 100644
--- a/drivers/gpu/drm/xe/xe_hwmon.c
+++ b/drivers/gpu/drm/xe/xe_hwmon.c
@@ -172,8 +172,8 @@ static int xe_hwmon_pcode_read_power_limit(const struct xe_hwmon *hwmon, u32 att
return ret;
}
-static int xe_hwmon_pcode_write_power_limit(const struct xe_hwmon *hwmon, u32 attr, u8 channel,
- u32 uval)
+static int xe_hwmon_pcode_rmw_power_limit(const struct xe_hwmon *hwmon, u32 attr, u8 channel,
+ u32 clr, u32 set)
{
struct xe_tile *root_tile = xe_device_get_root_tile(hwmon->xe);
u32 val0, val1;
@@ -192,9 +192,9 @@ static int xe_hwmon_pcode_write_power_limit(const struct xe_hwmon *hwmon, u32 at
channel, val0, val1, ret);
if (attr == PL1_HWMON_ATTR)
- val0 = uval;
+ val0 = (val0 & ~clr) | set;
else if (attr == PL2_HWMON_ATTR)
- val1 = uval;
+ val1 = (val1 & ~clr) | set;
else
return -EIO;
@@ -326,7 +326,7 @@ static int xe_hwmon_power_max_write(struct xe_hwmon *hwmon, u32 attr, int channe
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_rmw_power_limit(hwmon, attr, channel, PWR_LIM_EN, 0);
xe_hwmon_pcode_read_power_limit(hwmon, attr, channel, ®_val);
} else {
reg_val = xe_mmio_rmw32(mmio, rapl_limit, PWR_LIM_EN, 0);
@@ -362,10 +362,9 @@ static int xe_hwmon_power_max_write(struct xe_hwmon *hwmon, u32 attr, int channe
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);
+ ret = xe_hwmon_pcode_rmw_power_limit(hwmon, attr, channel, PWR_LIM, reg_val);
else
- reg_val = xe_mmio_rmw32(mmio, rapl_limit, PWR_LIM_EN | PWR_LIM_VAL,
- reg_val);
+ reg_val = xe_mmio_rmw32(mmio, rapl_limit, PWR_LIM, reg_val);
unlock:
mutex_unlock(&hwmon->hwmon_lock);
return ret;
@@ -577,14 +576,11 @@ xe_hwmon_power_max_interval_store(struct device *dev, struct device_attribute *a
mutex_lock(&hwmon->hwmon_lock);
- 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;
- xe_hwmon_pcode_write_power_limit(hwmon, power_attr, channel, r);
- } else {
+ if (hwmon->xe->info.has_mbx_power_limits)
+ xe_hwmon_pcode_rmw_power_limit(hwmon, power_attr, channel, PWR_LIM_TIME, rxy);
+ 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);
@@ -1160,25 +1156,25 @@ xe_hwmon_get_preregistration_info(struct xe_device *xe)
&hwmon->pl1_on_boot[CHANNEL_PKG]) |
xe_hwmon_pcode_read_power_limit(hwmon, PL2_HWMON_ATTR, CHANNEL_CARD,
&hwmon->pl2_on_boot[CHANNEL_CARD]) |
- xe_hwmon_pcode_read_power_limit(hwmon, PL1_HWMON_ATTR, CHANNEL_PKG,
+ xe_hwmon_pcode_read_power_limit(hwmon, PL2_HWMON_ATTR, CHANNEL_PKG,
&hwmon->pl2_on_boot[CHANNEL_PKG])) {
drm_warn(&hwmon->xe->drm,
"Failed to read power limits, check GPU firmware !\n");
} else {
drm_info(&hwmon->xe->drm, "Using mailbox commands for power limits\n");
/* 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]);
- xe_hwmon_pcode_write_power_limit(hwmon, PL2_HWMON_ATTR,
- CHANNEL_CARD,
- hwmon->pl2_on_boot[CHANNEL_CARD]);
- xe_hwmon_pcode_write_power_limit(hwmon, PL2_HWMON_ATTR,
- CHANNEL_PKG,
- hwmon->pl2_on_boot[CHANNEL_PKG]);
+ xe_hwmon_pcode_rmw_power_limit(hwmon, PL1_HWMON_ATTR,
+ CHANNEL_CARD, PWR_LIM | PWR_LIM_TIME,
+ hwmon->pl1_on_boot[CHANNEL_CARD]);
+ xe_hwmon_pcode_rmw_power_limit(hwmon, PL1_HWMON_ATTR,
+ CHANNEL_PKG, PWR_LIM | PWR_LIM_TIME,
+ hwmon->pl1_on_boot[CHANNEL_PKG]);
+ xe_hwmon_pcode_rmw_power_limit(hwmon, PL2_HWMON_ATTR,
+ CHANNEL_CARD, PWR_LIM | PWR_LIM_TIME,
+ hwmon->pl2_on_boot[CHANNEL_CARD]);
+ xe_hwmon_pcode_rmw_power_limit(hwmon, PL2_HWMON_ATTR,
+ CHANNEL_PKG, PWR_LIM | PWR_LIM_TIME,
+ hwmon->pl2_on_boot[CHANNEL_PKG]);
hwmon->scl_shift_power = PWR_UNIT;
hwmon->scl_shift_energy = ENERGY_UNIT;
hwmon->scl_shift_time = TIME_UNIT;
--
2.48.1
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