drm/i915/guc/slpc: Add methods to set min/max frequency

Add param set h2g helpers to set the min and max frequencies
for use by SLPC.

v2: Address review comments (Michal W)
v3: Check for positive error code (Michal W)
v4: Print generic error in set_param (Michal W)
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Sundaresan Sujaritha <sujaritha.sundaresan@intel.com>
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210730202119.23810-8-vinay.belgaumkar@intel.com

drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c

@@ -111,6 +111,21 @@ static u32 slpc_get_state(struct intel_guc_slpc *slpc)
 	return data->header.global_state;
 }
 
+static int guc_action_slpc_set_param(struct intel_guc *guc, u8 id, u32 value)
+{
+	u32 request[] = {
+		GUC_ACTION_HOST2GUC_PC_SLPC_REQUEST,
+		SLPC_EVENT(SLPC_EVENT_PARAMETER_SET, 2),
+		id,
+		value,
+	};
+	int ret;
+
+	ret = intel_guc_send(guc, request, ARRAY_SIZE(request));
+
+	return ret > 0 ? -EPROTO : ret;
+}
+
 static bool slpc_is_running(struct intel_guc_slpc *slpc)
 {
 	return slpc_get_state(slpc) == SLPC_GLOBAL_STATE_RUNNING;
@@ -148,6 +163,22 @@ static int slpc_query_task_state(struct intel_guc_slpc *slpc)
 	return ret;
 }
 
+static int slpc_set_param(struct intel_guc_slpc *slpc, u8 id, u32 value)
+{
+	struct intel_guc *guc = slpc_to_guc(slpc);
+	struct drm_i915_private *i915 = slpc_to_i915(slpc);
+	int ret;
+
+	GEM_BUG_ON(id >= SLPC_MAX_PARAM);
+
+	ret = guc_action_slpc_set_param(guc, id, value);
+	if (ret)
+		drm_err(&i915->drm, "Failed to set param %d to %u (%pe)\n",
+			id, value, ERR_PTR(ret));
+
+	return ret;
+}
+
 static const char *slpc_global_state_to_string(enum slpc_global_state state)
 {
 	switch (state) {
@@ -231,6 +262,64 @@ static void slpc_shared_data_reset(struct slpc_shared_data *data)
 			      SLPC_PARAM_TASK_DISABLE_DCC);
 }
 
+/**
+ * intel_guc_slpc_set_max_freq() - Set max frequency limit for SLPC.
+ * @slpc: pointer to intel_guc_slpc.
+ * @val: frequency (MHz)
+ *
+ * This function will invoke GuC SLPC action to update the max frequency
+ * limit for unslice.
+ *
+ * Return: 0 on success, non-zero error code on failure.
+ */
+int intel_guc_slpc_set_max_freq(struct intel_guc_slpc *slpc, u32 val)
+{
+	struct drm_i915_private *i915 = slpc_to_i915(slpc);
+	intel_wakeref_t wakeref;
+	int ret;
+
+	with_intel_runtime_pm(&i915->runtime_pm, wakeref) {
+		ret = slpc_set_param(slpc,
+				     SLPC_PARAM_GLOBAL_MAX_GT_UNSLICE_FREQ_MHZ,
+				     val);
+
+		/* Return standardized err code for sysfs calls */
+		if (ret)
+			ret = -EIO;
+	}
+
+	return ret;
+}
+
+/**
+ * intel_guc_slpc_set_min_freq() - Set min frequency limit for SLPC.
+ * @slpc: pointer to intel_guc_slpc.
+ * @val: frequency (MHz)
+ *
+ * This function will invoke GuC SLPC action to update the min unslice
+ * frequency.
+ *
+ * Return: 0 on success, non-zero error code on failure.
+ */
+int intel_guc_slpc_set_min_freq(struct intel_guc_slpc *slpc, u32 val)
+{
+	struct drm_i915_private *i915 = slpc_to_i915(slpc);
+	intel_wakeref_t wakeref;
+	int ret;
+
+	with_intel_runtime_pm(&i915->runtime_pm, wakeref) {
+		ret = slpc_set_param(slpc,
+				     SLPC_PARAM_GLOBAL_MIN_GT_UNSLICE_FREQ_MHZ,
+				     val);
+
+		/* Return standardized err code for sysfs calls */
+		if (ret)
+			ret = -EIO;
+	}
+
+	return ret;
+}
+
 /*
  * intel_guc_slpc_enable() - Start SLPC
  * @slpc: pointer to intel_guc_slpc.

drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h

@@ -29,5 +29,7 @@ void intel_guc_slpc_init_early(struct intel_guc_slpc *slpc);
 int intel_guc_slpc_init(struct intel_guc_slpc *slpc);
 int intel_guc_slpc_enable(struct intel_guc_slpc *slpc);
 void intel_guc_slpc_fini(struct intel_guc_slpc *slpc);
+int intel_guc_slpc_set_max_freq(struct intel_guc_slpc *slpc, u32 val);
+int intel_guc_slpc_set_min_freq(struct intel_guc_slpc *slpc, u32 val);
 
 #endif