drm/amd/pm: setup the framework to support Wifi RFI mitigation feature

With WBRF feature supported, as a driver responding to the frequencies,
amdgpu driver is able to do shadow pstate switching to mitigate possible
interference(between its (G-)DDR memory clocks and local radio module
frequency bands used by Wifi 6/6e/7).

--
v1->v2:
  - update the prompt for feature support(Lijo)
v8->v9:
  - update parameter document for smu_wbrf_event_handler(Simon)
v9->v10:
v10->v11:
 - correct the logics for wbrf range sorting(Lijo)
v13:
 - Fix the format issue (IIpo Jarvinen)

Signed-off-by: Evan Quan <quanliangl@hotmail.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Ma Jun <Jun.Ma2@amd.com>
Signed-off-by: Ma Jun <Jun.Ma2@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu.h

@@ -252,6 +252,8 @@ extern int amdgpu_seamless;
 extern int amdgpu_user_partt_mode;
 extern int amdgpu_agp;
 
+extern int amdgpu_wbrf;
+
 #define AMDGPU_VM_MAX_NUM_CTX			4096
 #define AMDGPU_SG_THRESHOLD			(256*1024*1024)
 #define AMDGPU_WAIT_IDLE_TIMEOUT_IN_MS	        3000

drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c

@@ -208,6 +208,7 @@ int amdgpu_umsch_mm;
 int amdgpu_seamless = -1; /* auto */
 uint amdgpu_debug_mask;
 int amdgpu_agp = -1; /* auto */
+int amdgpu_wbrf = -1;
 
 static void amdgpu_drv_delayed_reset_work_handler(struct work_struct *work);
 
@@ -971,6 +972,22 @@ module_param_named(debug_mask, amdgpu_debug_mask, uint, 0444);
 MODULE_PARM_DESC(agp, "AGP (-1 = auto (default), 0 = disable, 1 = enable)");
 module_param_named(agp, amdgpu_agp, int, 0444);
 
+/**
+ * DOC: wbrf (int)
+ * Enable Wifi RFI interference mitigation feature.
+ * Due to electrical and mechanical constraints there may be likely interference of
+ * relatively high-powered harmonics of the (G-)DDR memory clocks with local radio
+ * module frequency bands used by Wifi 6/6e/7. To mitigate the possible RFI interference,
+ * with this feature enabled, PMFW will use either “shadowed P-State” or “P-State” based
+ * on active list of frequencies in-use (to be avoided) as part of initial setting or
+ * P-state transition. However, there may be potential performance impact with this
+ * feature enabled.
+ * (0 = disabled, 1 = enabled, -1 = auto (default setting, will be enabled if supported))
+ */
+MODULE_PARM_DESC(wbrf,
+	"Enable Wifi RFI interference mitigation (0 = disabled, 1 = enabled, -1 = auto(default)");
+module_param_named(wbrf, amdgpu_wbrf, int, 0444);
+
 /* These devices are not supported by amdgpu.
  * They are supported by the mach64, r128, radeon drivers
  */

drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c

@@ -1322,6 +1322,170 @@ static int smu_get_thermal_temperature_range(struct smu_context *smu)
 	return ret;
 }
 
+/**
+ * smu_wbrf_handle_exclusion_ranges - consume the wbrf exclusion ranges
+ *
+ * @smu: smu_context pointer
+ *
+ * Retrieve the wbrf exclusion ranges and send them to PMFW for proper handling.
+ * Returns 0 on success, error on failure.
+ */
+static int smu_wbrf_handle_exclusion_ranges(struct smu_context *smu)
+{
+	struct wbrf_ranges_in_out wbrf_exclusion = {0};
+	struct freq_band_range *wifi_bands = wbrf_exclusion.band_list;
+	struct amdgpu_device *adev = smu->adev;
+	uint32_t num_of_wbrf_ranges = MAX_NUM_OF_WBRF_RANGES;
+	uint64_t start, end;
+	int ret, i, j;
+
+	ret = amd_wbrf_retrieve_freq_band(adev->dev, &wbrf_exclusion);
+	if (ret) {
+		dev_err(adev->dev, "Failed to retrieve exclusion ranges!\n");
+		return ret;
+	}
+
+	/*
+	 * The exclusion ranges array we got might be filled with holes and duplicate
+	 * entries. For example:
+	 * {(2400, 2500), (0, 0), (6882, 6962), (2400, 2500), (0, 0), (6117, 6189), (0, 0)...}
+	 * We need to do some sortups to eliminate those holes and duplicate entries.
+	 * Expected output: {(2400, 2500), (6117, 6189), (6882, 6962), (0, 0)...}
+	 */
+	for (i = 0; i < num_of_wbrf_ranges; i++) {
+		start = wifi_bands[i].start;
+		end = wifi_bands[i].end;
+
+		/* get the last valid entry to fill the intermediate hole */
+		if (!start && !end) {
+			for (j = num_of_wbrf_ranges - 1; j > i; j--)
+				if (wifi_bands[j].start && wifi_bands[j].end)
+					break;
+
+			/* no valid entry left */
+			if (j <= i)
+				break;
+
+			start = wifi_bands[i].start = wifi_bands[j].start;
+			end = wifi_bands[i].end = wifi_bands[j].end;
+			wifi_bands[j].start = 0;
+			wifi_bands[j].end = 0;
+			num_of_wbrf_ranges = j;
+		}
+
+		/* eliminate duplicate entries */
+		for (j = i + 1; j < num_of_wbrf_ranges; j++) {
+			if ((wifi_bands[j].start == start) && (wifi_bands[j].end == end)) {
+				wifi_bands[j].start = 0;
+				wifi_bands[j].end = 0;
+			}
+		}
+	}
+
+	/* Send the sorted wifi_bands to PMFW */
+	ret = smu_set_wbrf_exclusion_ranges(smu, wifi_bands);
+	/* Try to set the wifi_bands again */
+	if (unlikely(ret == -EBUSY)) {
+		mdelay(5);
+		ret = smu_set_wbrf_exclusion_ranges(smu, wifi_bands);
+	}
+
+	return ret;
+}
+
+/**
+ * smu_wbrf_event_handler - handle notify events
+ *
+ * @nb: notifier block
+ * @action: event type
+ * @_arg: event data
+ *
+ * Calls relevant amdgpu function in response to wbrf event
+ * notification from kernel.
+ */
+static int smu_wbrf_event_handler(struct notifier_block *nb,
+				  unsigned long action, void *_arg)
+{
+	struct smu_context *smu = container_of(nb, struct smu_context, wbrf_notifier);
+
+	switch (action) {
+	case WBRF_CHANGED:
+		smu_wbrf_handle_exclusion_ranges(smu);
+		break;
+	default:
+		return NOTIFY_DONE;
+	};
+
+	return NOTIFY_OK;
+}
+
+/**
+ * smu_wbrf_support_check - check wbrf support
+ *
+ * @smu: smu_context pointer
+ *
+ * Verifies the ACPI interface whether wbrf is supported.
+ */
+static void smu_wbrf_support_check(struct smu_context *smu)
+{
+	struct amdgpu_device *adev = smu->adev;
+
+	smu->wbrf_supported = smu_is_asic_wbrf_supported(smu) && amdgpu_wbrf &&
+							acpi_amd_wbrf_supported_consumer(adev->dev);
+
+	if (smu->wbrf_supported)
+		dev_info(adev->dev, "RF interference mitigation is supported\n");
+}
+
+/**
+ * smu_wbrf_init - init driver wbrf support
+ *
+ * @smu: smu_context pointer
+ *
+ * Verifies the AMD ACPI interfaces and registers with the wbrf
+ * notifier chain if wbrf feature is supported.
+ * Returns 0 on success, error on failure.
+ */
+static int smu_wbrf_init(struct smu_context *smu)
+{
+	struct amdgpu_device *adev = smu->adev;
+	int ret;
+
+	if (!smu->wbrf_supported)
+		return 0;
+
+	smu->wbrf_notifier.notifier_call = smu_wbrf_event_handler;
+	ret = amd_wbrf_register_notifier(&smu->wbrf_notifier);
+	if (ret)
+		return ret;
+
+	/*
+	 * Some wifiband exclusion ranges may be already there
+	 * before our driver loaded. To make sure our driver
+	 * is awared of those exclusion ranges.
+	 */
+	ret = smu_wbrf_handle_exclusion_ranges(smu);
+	if (ret)
+		dev_err(adev->dev, "Failed to handle wbrf exclusion ranges\n");
+
+	return ret;
+}
+
+/**
+ * smu_wbrf_fini - tear down driver wbrf support
+ *
+ * @smu: smu_context pointer
+ *
+ * Unregisters with the wbrf notifier chain.
+ */
+static void smu_wbrf_fini(struct smu_context *smu)
+{
+	if (!smu->wbrf_supported)
+		return;
+
+	amd_wbrf_unregister_notifier(&smu->wbrf_notifier);
+}
+
 static int smu_smc_hw_setup(struct smu_context *smu)
 {
 	struct smu_feature *feature = &smu->smu_feature;
@@ -1414,6 +1578,15 @@ static int smu_smc_hw_setup(struct smu_context *smu)
 	if (ret)
 		return ret;
 
+	/* Enable UclkShadow on wbrf supported */
+	if (smu->wbrf_supported) {
+		ret = smu_enable_uclk_shadow(smu, true);
+		if (ret) {
+			dev_err(adev->dev, "Failed to enable UclkShadow feature to support wbrf!\n");
+			return ret;
+		}
+	}
+
 	/*
 	 * With SCPM enabled, these actions(and relevant messages) are
 	 * not needed and permitted.
@@ -1512,6 +1685,15 @@ static int smu_smc_hw_setup(struct smu_context *smu)
 	 */
 	ret = smu_set_min_dcef_deep_sleep(smu,
 					  smu->smu_table.boot_values.dcefclk / 100);
+	if (ret) {
+		dev_err(adev->dev, "Error setting min deepsleep dcefclk\n");
+		return ret;
+	}
+
+	/* Init wbrf support. Properly setup the notifier */
+	ret = smu_wbrf_init(smu);
+	if (ret)
+		dev_err(adev->dev, "Error during wbrf init call\n");
 
 	return ret;
 }
@@ -1567,6 +1749,13 @@ static int smu_hw_init(void *handle)
 		return ret;
 	}
 
+	/*
+	 * Check whether wbrf is supported. This needs to be done
+	 * before SMU setup starts since part of SMU configuration
+	 * relies on this.
+	 */
+	smu_wbrf_support_check(smu);
+
 	if (smu->is_apu) {
 		ret = smu_set_gfx_imu_enable(smu);
 		if (ret)
@@ -1733,6 +1922,8 @@ static int smu_smc_hw_cleanup(struct smu_context *smu)
 	struct amdgpu_device *adev = smu->adev;
 	int ret = 0;
 
+	smu_wbrf_fini(smu);
+
 	cancel_work_sync(&smu->throttling_logging_work);
 	cancel_work_sync(&smu->interrupt_work);
 

drivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h

@@ -22,6 +22,8 @@
 #ifndef __AMDGPU_SMU_H__
 #define __AMDGPU_SMU_H__
 
+#include <linux/acpi_amd_wbrf.h>
+
 #include "amdgpu.h"
 #include "kgd_pp_interface.h"
 #include "dm_pp_interface.h"
@@ -570,6 +572,10 @@ struct smu_context {
 	struct delayed_work		swctf_delayed_work;
 
 	enum pp_xgmi_plpd_mode plpd_mode;
+
+	/* data structures for wbrf feature support */
+	bool				wbrf_supported;
+	struct notifier_block		wbrf_notifier;
 };
 
 struct i2c_adapter;
@@ -1375,6 +1381,22 @@ struct pptable_funcs {
 	 * @notify_rlc_state: Notify RLC power state to SMU.
 	 */
 	int (*notify_rlc_state)(struct smu_context *smu, bool en);
+
+	/**
+	 * @is_asic_wbrf_supported: check whether PMFW supports the wbrf feature
+	 */
+	bool (*is_asic_wbrf_supported)(struct smu_context *smu);
+
+	/**
+	 * @enable_uclk_shadow: Enable the uclk shadow feature on wbrf supported
+	 */
+	int (*enable_uclk_shadow)(struct smu_context *smu, bool enable);
+
+	/**
+	 * @set_wbrf_exclusion_ranges: notify SMU the wifi bands occupied
+	 */
+	int (*set_wbrf_exclusion_ranges)(struct smu_context *smu,
+					struct freq_band_range *exclusion_ranges);
 };
 
 typedef enum {

drivers/gpu/drm/amd/pm/swsmu/smu_internal.h

@@ -98,6 +98,9 @@
 #define smu_set_config_table(smu, config_table)				smu_ppt_funcs(set_config_table, -EOPNOTSUPP, smu, config_table)
 #define smu_init_pptable_microcode(smu)					smu_ppt_funcs(init_pptable_microcode, 0, smu)
 #define smu_notify_rlc_state(smu, en)					smu_ppt_funcs(notify_rlc_state, 0, smu, en)
+#define smu_is_asic_wbrf_supported(smu)			smu_ppt_funcs(is_asic_wbrf_supported, false, smu)
+#define smu_enable_uclk_shadow(smu, enable)		smu_ppt_funcs(enable_uclk_shadow, 0, smu, enable)
+#define smu_set_wbrf_exclusion_ranges(smu, freq_band_range)		smu_ppt_funcs(set_wbrf_exclusion_ranges, -EOPNOTSUPP, smu, freq_band_range)
 
 #endif
 #endif