drm/xe/hwmon: Add support to manage power limits though mailbox

Add support to manage power limits using pcode mailbox commands
for supported platforms.

v2:
 - Address review comments. (Badal)
 - Use mailbox commands instead of registers to manage power limits
   for BMG.
 - Clamp the maximum power limit to GPU firmware default value.

v3:
 - Clamp power limit in write also for platforms with mailbox support.

v4:
 - Remove unnecessary debug prints. (Badal)

v5:
 - Update description of variable pl1_on_boot to fix kernel-doc error.

v6:
 - Improve commit message, refer to BIOS as GPU firmware.
 - Change macro READ_PL_FROM_BIOS to READ_PL_FROM_FW.
 - Rectify drm_warn to drm_info.

Signed-off-by: Karthik Poosa <karthik.poosa@intel.com>
Fixes: e90f7a58e659 ("drm/xe/hwmon: Add HWMON support for BMG")
Reviewed-by: Badal Nilawar <badal.nilawar@intel.com>
Link: https://lore.kernel.org/r/20250529163458.2354509-2-karthik.poosa@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
(cherry picked from commit 7596d839f6228757fe17a810da2d1c5f3305078c)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>

1 files changed, 11 insertions, 0 deletions

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;