[Intel-xe] [PATCH v2] drm/xe: Donot apply forcewake while reading actual frequency

[Badal Nilawar]

RPSTAT1 is an sgunit register and thus doesn't need forcewake.
MTL_MIRROR_TARGET_WP1 is within an "always on" power domain and thus
doesn't require any forcewake to ensure the register is powered
up and usable. When GT is RC6 the actual frequency reported will be 0.

v2:
 - Add bspec index (Anshuman)
 - %s/GEN12_RPSTAT1/GT_PERF_STATUS as per bspec

Bspec: 51837, 67651
Fixes: 7dbca224f176 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Signed-off-by: Badal Nilawar <badal.nilawar at intel.com>
Reviewed-by: Matt Roper <matthew.d.roper at intel.com>
---
 drivers/gpu/drm/xe/xe_guc_pc.c | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_guc_pc.c b/drivers/gpu/drm/xe/xe_guc_pc.c
index 67faa9ee0006..5d5cf4b0d508 100644
--- a/drivers/gpu/drm/xe/xe_guc_pc.c
+++ b/drivers/gpu/drm/xe/xe_guc_pc.c
@@ -31,7 +31,7 @@
 #define GEN10_FREQ_INFO_REC	XE_REG(MCHBAR_MIRROR_BASE_SNB + 0x5ef0)
 #define   RPE_MASK		REG_GENMASK(15, 8)
 
-#define GEN12_RPSTAT1		XE_REG(0x1381b4)
+#define GT_PERF_STATUS		XE_REG(0x1381b4)
 #define   GEN12_CAGF_MASK	REG_GENMASK(19, 11)
 
 #define MTL_MIRROR_TARGET_WP1	XE_REG(0xc60)
@@ -371,26 +371,18 @@ static ssize_t freq_act_show(struct device *dev,
 	ssize_t ret;
 
 	xe_device_mem_access_get(gt_to_xe(gt));
-	/*
-	 * When in RC6, actual frequency is 0. Let's block RC6 so we are able
-	 * to verify that our freq requests are really happening.
-	 */
-	ret = xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL);
-	if (ret)
-		goto out;
 
+	/* When in RC6, actual frequency reported will be 0. */
 	if (xe->info.platform == XE_METEORLAKE) {
 		freq = xe_mmio_read32(gt, MTL_MIRROR_TARGET_WP1);
 		freq = REG_FIELD_GET(MTL_CAGF_MASK, freq);
 	} else {
-		freq = xe_mmio_read32(gt, GEN12_RPSTAT1);
+		freq = xe_mmio_read32(gt, GT_PERF_STATUS);
 		freq = REG_FIELD_GET(GEN12_CAGF_MASK, freq);
 	}
 
 	ret = sysfs_emit(buf, "%d\n", decode_freq(freq));
 
-	XE_WARN_ON(xe_force_wake_put(gt_to_fw(gt), XE_FORCEWAKE_ALL));
-out:
 	xe_device_mem_access_put(gt_to_xe(gt));
 	return ret;
 }
-- 
2.25.1