drm/xe/guc: Eliminate RPe caching for SLPC parameter handling

RPe is runtime-determined by PCODE and caching it caused stale values,
leading to incorrect GuC SLPC parameter settings.
Drop the cached rpe_freq field and query fresh values from hardware
on each use to ensure GuC SLPC parameters reflect current RPe.

v2: Remove cached RPe frequency field (Rodrigo)
v3: Remove extra variable (Vinay)
    Modify function name (Vinay)
v4: Maintain a separate function for PVC (Rodrigo)
v5: Avoid RPn update while fetching RPe frequency (Rodrigo)
v6: Split platform-specific RPe comments (Vinay)

Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/5166
Signed-off-by: Sk Anirban <sk.anirban@intel.com>
Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Link: https://patch.msgid.link/20251112185153.3593145-5-sk.anirban@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/xe/xe_guc_pc.c b/drivers/gpu/drm/xe/xe_guc_pc.c
index ff22235857f8825e6531d21c52941edefe63a537..4c48115f17951744bc5b98be765f7617ee0b197f 100644 (file)
--- a/drivers/gpu/drm/xe/xe_guc_pc.c
+++ b/drivers/gpu/drm/xe/xe_guc_pc.c
@@ -331,7 +331,7 @@ static int pc_set_min_freq(struct xe_guc_pc *pc, u32 freq)
         * Our goal is to have the admin choices respected.
         */
        pc_action_set_param(pc, SLPC_PARAM_IGNORE_EFFICIENT_FREQUENCY,
-                           freq < pc->rpe_freq);
+                           freq < xe_guc_pc_get_rpe_freq(pc));
 
        return pc_action_set_param(pc,
                                   SLPC_PARAM_GLOBAL_MIN_GT_UNSLICE_FREQ_MHZ,
@@ -376,7 +376,7 @@ static void mtl_update_rpa_value(struct xe_guc_pc *pc)
        pc->rpa_freq = decode_freq(REG_FIELD_GET(MTL_RPA_MASK, reg));
 }
 
-static void mtl_update_rpe_value(struct xe_guc_pc *pc)
+static u32 mtl_get_rpe_freq(struct xe_guc_pc *pc)
 {
        struct xe_gt *gt = pc_to_gt(pc);
        u32 reg;
@@ -386,7 +386,7 @@ static void mtl_update_rpe_value(struct xe_guc_pc *pc)
        else
                reg = xe_mmio_read32(&gt->mmio, MTL_GT_RPE_FREQUENCY);
 
-       pc->rpe_freq = decode_freq(REG_FIELD_GET(MTL_RPE_MASK, reg));
+       return decode_freq(REG_FIELD_GET(MTL_RPE_MASK, reg));
 }
 
 static void tgl_update_rpa_value(struct xe_guc_pc *pc)
@@ -409,24 +409,29 @@ static void tgl_update_rpa_value(struct xe_guc_pc *pc)
        }
 }
 
-static void tgl_update_rpe_value(struct xe_guc_pc *pc)
+static u32 pvc_get_rpe_freq(struct xe_guc_pc *pc)
 {
        struct xe_gt *gt = pc_to_gt(pc);
-       struct xe_device *xe = gt_to_xe(gt);
        u32 reg;
 
        /*
         * For PVC we still need to use fused RP1 as the approximation for RPe
-        * For other platforms than PVC we get the resolved RPe directly from
+        */
+       reg = xe_mmio_read32(&gt->mmio, PVC_RP_STATE_CAP);
+       return REG_FIELD_GET(RP1_MASK, reg) * GT_FREQUENCY_MULTIPLIER;
+}
+
+static u32 tgl_get_rpe_freq(struct xe_guc_pc *pc)
+{
+       struct xe_gt *gt = pc_to_gt(pc);
+       u32 reg;
+
+       /*
+        * For other platforms than PVC, we get the resolved RPe directly from
         * PCODE at a different register
         */
-       if (xe->info.platform == XE_PVC) {
-               reg = xe_mmio_read32(&gt->mmio, PVC_RP_STATE_CAP);
-               pc->rpe_freq = REG_FIELD_GET(RP1_MASK, reg) * GT_FREQUENCY_MULTIPLIER;
-       } else {
-               reg = xe_mmio_read32(&gt->mmio, FREQ_INFO_REC);
-               pc->rpe_freq = REG_FIELD_GET(RPE_MASK, reg) * GT_FREQUENCY_MULTIPLIER;
-       }
+       reg = xe_mmio_read32(&gt->mmio, FREQ_INFO_REC);
+       return REG_FIELD_GET(RPE_MASK, reg) * GT_FREQUENCY_MULTIPLIER;
 }
 
 static void pc_update_rp_values(struct xe_guc_pc *pc)
@@ -434,20 +439,10 @@ static void pc_update_rp_values(struct xe_guc_pc *pc)
        struct xe_gt *gt = pc_to_gt(pc);
        struct xe_device *xe = gt_to_xe(gt);
 
-       if (GRAPHICS_VERx100(xe) >= 1270) {
+       if (GRAPHICS_VERx100(xe) >= 1270)
                mtl_update_rpa_value(pc);
-               mtl_update_rpe_value(pc);
-       } else {
+       else
                tgl_update_rpa_value(pc);
-               tgl_update_rpe_value(pc);
-       }
-
-       /*
-        * RPe is decided at runtime by PCODE. In the rare case where that's
-        * smaller than the fused min, we will trust the PCODE and use that
-        * as our minimum one.
-        */
-       pc->rpn_freq = min(pc->rpn_freq, pc->rpe_freq);
 }
 
 /**
@@ -561,9 +556,17 @@ u32 xe_guc_pc_get_rpa_freq(struct xe_guc_pc *pc)
  */
 u32 xe_guc_pc_get_rpe_freq(struct xe_guc_pc *pc)
 {
-       pc_update_rp_values(pc);
+       struct xe_device *xe = pc_to_xe(pc);
+       u32 freq;
 
-       return pc->rpe_freq;
+       if (GRAPHICS_VERx100(xe) == 1260)
+               freq = pvc_get_rpe_freq(pc);
+       else if (GRAPHICS_VERx100(xe) >= 1270)
+               freq = mtl_get_rpe_freq(pc);
+       else
+               freq = tgl_get_rpe_freq(pc);
+
+       return freq;
 }
 
 /**
@@ -1022,7 +1025,7 @@ static int pc_set_mert_freq_cap(struct xe_guc_pc *pc)
        /*
         * Ensure min and max are bound by MERT_FREQ_CAP until driver loads.
         */
-       ret = pc_set_min_freq(pc, min(pc->rpe_freq, pc_max_freq_cap(pc)));
+       ret = pc_set_min_freq(pc, min(xe_guc_pc_get_rpe_freq(pc), pc_max_freq_cap(pc)));
        if (!ret)
                ret = pc_set_max_freq(pc, min(pc->rp0_freq, pc_max_freq_cap(pc)));
 
@@ -1340,7 +1343,7 @@ static void xe_guc_pc_fini_hw(void *arg)
        XE_WARN_ON(xe_guc_pc_stop(pc));
 
        /* Bind requested freq to mert_freq_cap before unload */
-       pc_set_cur_freq(pc, min(pc_max_freq_cap(pc), pc->rpe_freq));
+       pc_set_cur_freq(pc, min(pc_max_freq_cap(pc), xe_guc_pc_get_rpe_freq(pc)));
 
        xe_force_wake_put(gt_to_fw(pc_to_gt(pc)), fw_ref);
 }

diff --git a/drivers/gpu/drm/xe/xe_guc_pc_types.h b/drivers/gpu/drm/xe/xe_guc_pc_types.h
index 5e4ea53fbee6eea63ea3354002c71c7b48bff8a6..f27c05d8170656c58ff5b933acf009e61deb59fc 100644 (file)
--- a/drivers/gpu/drm/xe/xe_guc_pc_types.h
+++ b/drivers/gpu/drm/xe/xe_guc_pc_types.h
@@ -21,8 +21,6 @@ struct xe_guc_pc {
        u32 rp0_freq;
        /** @rpa_freq: HW RPa frequency - The Achievable one */
        u32 rpa_freq;
-       /** @rpe_freq: HW RPe frequency - The Efficient one */
-       u32 rpe_freq;
        /** @rpn_freq: HW RPN frequency - The Minimum one */
        u32 rpn_freq;
        /** @user_requested_min: Stash the minimum requested freq by user */