mt76: mt7921: introduce ACPI SAR support

In ACPI SAR enabled device, mt7921 should read power limit in ACPI config.
The limit value would be applied to regular tx power settings in mt76.

Two major functionalities added:
1. Get SAR power table through ACPI.
2. Read power in Dynamic/Geo SAR table for tx power limit.

Table note
MTDS: Dynamic SAR table
MTGS: Geo SAR table
MTCL: Country List table (for 6GHz support)

Reviewed-by: Sean Wang <sean.wang@mediatek.com>
Co-developed-by: Quan Zhou <quan.zhou@mediatek.com>
Signed-off-by: Quan Zhou <quan.zhou@mediatek.com>
Co-developed-by: Ming Yen Hsieh <mingyen.hsieh@mediatek.com>
Signed-off-by: Ming Yen Hsieh <mingyen.hsieh@mediatek.com>
Signed-off-by: Deren Wu <deren.wu@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7921/Makefile

@@ -9,6 +9,7 @@ CFLAGS_trace.o := -I$(src)
 
 mt7921-common-y := mac.o mcu.o main.o init.o debugfs.o trace.o
 mt7921-common-$(CONFIG_NL80211_TESTMODE) += testmode.o
+mt7921-common-$(CONFIG_ACPI) += acpi_sar.o
 mt7921e-y := pci.o pci_mac.o pci_mcu.o dma.o
 mt7921s-y := sdio.o sdio_mac.o sdio_mcu.o
 mt7921u-y := usb.o usb_mac.o

drivers/net/wireless/mediatek/mt76/mt7921/acpi_sar.c

@@ -0,0 +1,279 @@
+// SPDX-License-Identifier: ISC
+/* Copyright (C) 2022 MediaTek Inc. */
+
+#include <linux/acpi.h>
+#include "mt7921.h"
+
+static int
+mt7921_acpi_read(struct mt7921_dev *dev, u8 *method, u8 **tbl, u32 *len)
+{
+	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *sar_root, *sar_unit;
+	struct mt76_dev *mdev = &dev->mt76;
+	acpi_handle root, handle;
+	acpi_status status;
+	u32 i = 0;
+
+	root = ACPI_HANDLE(mdev->dev);
+	if (!root)
+		return -EOPNOTSUPP;
+
+	status = acpi_get_handle(root, method, &handle);
+	if (ACPI_FAILURE(status))
+		return -EIO;
+
+	status = acpi_evaluate_object(handle, NULL, NULL, &buf);
+	if (ACPI_FAILURE(status))
+		return -EIO;
+
+	sar_root = buf.pointer;
+	if (sar_root->type != ACPI_TYPE_PACKAGE ||
+	    sar_root->package.count < 4 ||
+	    sar_root->package.elements[0].type != ACPI_TYPE_INTEGER) {
+		dev_err(mdev->dev, "sar cnt = %d\n",
+			sar_root->package.count);
+		goto free;
+	}
+
+	if (!*tbl) {
+		*tbl = devm_kzalloc(mdev->dev, sar_root->package.count,
+				    GFP_KERNEL);
+		if (!*tbl)
+			goto free;
+	}
+	if (len)
+		*len = sar_root->package.count;
+
+	for (i = 0; i < sar_root->package.count; i++) {
+		sar_unit = &sar_root->package.elements[i];
+
+		if (sar_unit->type != ACPI_TYPE_INTEGER)
+			break;
+		*(*tbl + i) = (u8)sar_unit->integer.value;
+	}
+free:
+	kfree(sar_root);
+
+	return (i == sar_root->package.count) ? 0 : -EINVAL;
+}
+
+/* MTCL : Country List Table for 6G band */
+static int
+mt7921_asar_acpi_read_mtcl(struct mt7921_dev *dev, u8 **table, u8 *version)
+{
+	*version = (mt7921_acpi_read(dev, MT7921_ACPI_MTCL, table, 0) < 0)
+		   ? 1 : 2;
+	return 0;
+}
+
+/* MTDS : Dynamic SAR Power Table */
+static int
+mt7921_asar_acpi_read_mtds(struct mt7921_dev *dev, u8 **table, u8 version)
+{
+	int len, ret, sarlen, prelen, tblcnt;
+	bool enable;
+
+	ret = mt7921_acpi_read(dev, MT7921_ACPI_MTDS, table, &len);
+	if (ret)
+		return ret;
+
+	/* Table content validation */
+	switch (version) {
+	case 1:
+		enable = ((struct mt7921_asar_dyn *)*table)->enable;
+		sarlen = sizeof(struct mt7921_asar_dyn_limit);
+		prelen = sizeof(struct mt7921_asar_dyn);
+		break;
+	case 2:
+		enable = ((struct mt7921_asar_dyn_v2 *)*table)->enable;
+		sarlen = sizeof(struct mt7921_asar_dyn_limit_v2);
+		prelen = sizeof(struct mt7921_asar_dyn_v2);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	tblcnt = (len - prelen) / sarlen;
+	if (!enable ||
+	    tblcnt > MT7921_ASAR_MAX_DYN || tblcnt < MT7921_ASAR_MIN_DYN)
+		ret = -EINVAL;
+
+	return ret;
+}
+
+/* MTGS : Geo SAR Power Table */
+static int
+mt7921_asar_acpi_read_mtgs(struct mt7921_dev *dev, u8 **table, u8 version)
+{
+	int len, ret = 0, sarlen, prelen, tblcnt;
+
+	ret = mt7921_acpi_read(dev, MT7921_ACPI_MTGS, table, &len);
+	if (ret)
+		return ret;
+
+	/* Table content validation */
+	switch (version) {
+	case 1:
+		sarlen = sizeof(struct mt7921_asar_geo_limit);
+		prelen = sizeof(struct mt7921_asar_geo);
+		break;
+	case 2:
+		sarlen = sizeof(struct mt7921_asar_geo_limit_v2);
+		prelen = sizeof(struct mt7921_asar_geo_v2);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	tblcnt = (len - prelen) / sarlen;
+	if (tblcnt > MT7921_ASAR_MAX_GEO || tblcnt < MT7921_ASAR_MIN_GEO)
+		ret = -EINVAL;
+
+	return ret;
+}
+
+int mt7921_init_acpi_sar(struct mt7921_dev *dev)
+{
+	struct mt7921_acpi_sar *asar;
+	int ret;
+
+	asar = devm_kzalloc(dev->mt76.dev, sizeof(*asar), GFP_KERNEL);
+	if (!asar)
+		return -ENOMEM;
+
+	mt7921_asar_acpi_read_mtcl(dev, (u8 **)&asar->countrylist, &asar->ver);
+
+	/* MTDS is mandatory. Return error if table is invalid */
+	ret = mt7921_asar_acpi_read_mtds(dev, (u8 **)&asar->dyn, asar->ver);
+	if (ret) {
+		devm_kfree(dev->mt76.dev, asar->dyn);
+		devm_kfree(dev->mt76.dev, asar->countrylist);
+		devm_kfree(dev->mt76.dev, asar);
+		return ret;
+	}
+
+	/* MTGS is optional */
+	ret = mt7921_asar_acpi_read_mtgs(dev, (u8 **)&asar->geo, asar->ver);
+	if (ret) {
+		devm_kfree(dev->mt76.dev, asar->geo);
+		asar->geo = NULL;
+	}
+
+	dev->phy.acpisar = asar;
+
+	return 0;
+}
+
+static s8
+mt7921_asar_get_geo_pwr(struct mt7921_phy *phy,
+			enum nl80211_band band, s8 dyn_power)
+{
+	struct mt7921_acpi_sar *asar = phy->acpisar;
+	struct mt7921_asar_geo_band *band_pwr;
+	s8 geo_power;
+	u8 idx, max;
+
+	if (!asar->geo)
+		return dyn_power;
+
+	switch (phy->mt76->dev->region) {
+	case NL80211_DFS_FCC:
+		idx = 0;
+		break;
+	case NL80211_DFS_ETSI:
+		idx = 1;
+		break;
+	default: /* WW */
+		idx = 2;
+		break;
+	}
+
+	if (asar->ver == 1) {
+		band_pwr = &asar->geo->tbl[idx].band[0];
+		max = ARRAY_SIZE(asar->geo->tbl[idx].band);
+	} else {
+		band_pwr = &asar->geo_v2->tbl[idx].band[0];
+		max = ARRAY_SIZE(asar->geo_v2->tbl[idx].band);
+	}
+
+	switch (band) {
+	case NL80211_BAND_2GHZ:
+		idx = 0;
+		break;
+	case NL80211_BAND_5GHZ:
+		idx = 1;
+		break;
+	case NL80211_BAND_6GHZ:
+		idx = 2;
+		break;
+	default:
+		return dyn_power;
+	}
+
+	if (idx >= max)
+		return dyn_power;
+
+	geo_power = (band_pwr + idx)->pwr;
+	dyn_power += (band_pwr + idx)->offset;
+
+	return min(geo_power, dyn_power);
+}
+
+static s8
+mt7921_asar_range_pwr(struct mt7921_phy *phy,
+		      const struct cfg80211_sar_freq_ranges *range,
+		      u8 idx)
+{
+	const struct cfg80211_sar_capa *capa = phy->mt76->hw->wiphy->sar_capa;
+	struct mt7921_acpi_sar *asar = phy->acpisar;
+	u8 *limit, band, max;
+
+	if (!capa)
+		return 127;
+
+	if (asar->ver == 1) {
+		limit = &asar->dyn->tbl[0].frp[0];
+		max = ARRAY_SIZE(asar->dyn->tbl[0].frp);
+	} else {
+		limit = &asar->dyn_v2->tbl[0].frp[0];
+		max = ARRAY_SIZE(asar->dyn_v2->tbl[0].frp);
+	}
+
+	if (idx >= max)
+		return 127;
+
+	if (range->start_freq >= 5945)
+		band = NL80211_BAND_6GHZ;
+	else if (range->start_freq >= 5150)
+		band = NL80211_BAND_5GHZ;
+	else
+		band = NL80211_BAND_2GHZ;
+
+	return mt7921_asar_get_geo_pwr(phy, band, limit[idx]);
+}
+
+int mt7921_init_acpi_sar_power(struct mt7921_phy *phy, bool set_default)
+{
+	const struct cfg80211_sar_capa *capa = phy->mt76->hw->wiphy->sar_capa;
+	int i;
+
+	if (!phy->acpisar)
+		return 0;
+
+	/* When ACPI SAR enabled in HW, we should apply rules for .frp
+	 * 1. w/o .sar_specs : set ACPI SAR power as the defatul value
+	 * 2. w/  .sar_specs : set power with min(.sar_specs, ACPI_SAR)
+	 */
+	for (i = 0; i < capa->num_freq_ranges; i++) {
+		struct mt76_freq_range_power *frp = &phy->mt76->frp[i];
+
+		frp->range = set_default ? &capa->freq_ranges[i] : frp->range;
+		if (!frp->range)
+			continue;
+
+		frp->power = min_t(s8, set_default ? 127 : frp->power,
+				   mt7921_asar_range_pwr(phy, frp->range, i));
+	}
+
+	return 0;
+}

drivers/net/wireless/mediatek/mt76/mt7921/acpi_sar.h

@@ -0,0 +1,93 @@
+/* SPDX-License-Identifier: ISC */
+/* Copyright (C) 2022 MediaTek Inc. */
+
+#ifndef __MT7921_ACPI_SAR_H
+#define __MT7921_ACPI_SAR_H
+
+#define MT7921_ASAR_MIN_DYN		1
+#define MT7921_ASAR_MAX_DYN		8
+#define MT7921_ASAR_MIN_GEO		3
+#define MT7921_ASAR_MAX_GEO		8
+
+#define MT7921_ACPI_MTCL		"MTCL"
+#define MT7921_ACPI_MTDS		"MTDS"
+#define MT7921_ACPI_MTGS		"MTGS"
+
+struct mt7921_asar_dyn_limit {
+	u8 idx;
+	u8 frp[5];
+} __packed;
+
+struct mt7921_asar_dyn {
+	u8 names[4];
+	u8 enable;
+	u8 nr_tbl;
+	struct mt7921_asar_dyn_limit tbl[0];
+} __packed;
+
+struct mt7921_asar_dyn_limit_v2 {
+	u8 idx;
+	u8 frp[11];
+} __packed;
+
+struct mt7921_asar_dyn_v2 {
+	u8 names[4];
+	u8 enable;
+	u8 rsvd;
+	u8 nr_tbl;
+	struct mt7921_asar_dyn_limit_v2 tbl[0];
+} __packed;
+
+struct mt7921_asar_geo_band {
+	u8 pwr;
+	u8 offset;
+} __packed;
+
+struct mt7921_asar_geo_limit {
+	u8 idx;
+	/* 0:2G, 1:5G */
+	struct mt7921_asar_geo_band band[2];
+} __packed;
+
+struct mt7921_asar_geo {
+	u8 names[4];
+	u8 version;
+	u8 nr_tbl;
+	struct mt7921_asar_geo_limit tbl[0];
+} __packed;
+
+struct mt7921_asar_geo_limit_v2 {
+	u8 idx;
+	/* 0:2G, 1:5G, 2:6G */
+	struct mt7921_asar_geo_band band[3];
+} __packed;
+
+struct mt7921_asar_geo_v2 {
+	u8 names[4];
+	u8 version;
+	u8 rsvd;
+	u8 nr_tbl;
+	struct mt7921_asar_geo_limit_v2 tbl[0];
+} __packed;
+
+struct mt7921_asar_cl {
+	u8 names[4];
+	u8 version;
+	u8 mode_6g;
+	u8 cl6g[6];
+} __packed;
+
+struct mt7921_acpi_sar {
+	u8 ver;
+	union {
+		struct mt7921_asar_dyn *dyn;
+		struct mt7921_asar_dyn_v2 *dyn_v2;
+	};
+	union {
+		struct mt7921_asar_geo *geo;
+		struct mt7921_asar_geo_v2 *geo_v2;
+	};
+	struct mt7921_asar_cl *countrylist;
+};
+
+#endif

drivers/net/wireless/mediatek/mt76/mt7921/init.c

@@ -289,6 +289,8 @@ int mt7921_register_device(struct mt7921_dev *dev)
 	if (!mt76_is_mmio(&dev->mt76))
 		hw->extra_tx_headroom += MT_SDIO_TXD_SIZE + MT_SDIO_HDR_SIZE;
 
+	mt7921_init_acpi_sar(dev);
+
 	ret = mt7921_init_wcid(dev);
 	if (ret)
 		return ret;