wifi: rtw89: acpi: process 6 GHz SP policy from ACPI DSM

Realtek ACPI DSM func 7, RTW89_ACPI_DSM_FUNC_6GHZ_SP_SUP, accepts a format
via ACPI buffer as below.

| index | description                      |
--------------------------------------------
| [0-3] | signature                        |
| [4]   | revision                         |
| [5]   | override driver settings, or not |
| [6]   | configuration if override        |
| [7]   | reserved                         |

	where field of [6] is a bitmap by country,
	and for now, only define BIT(0) is for US.

Through this function with overriding, BIOS can indicate to allow/block
6 GHz SP power by country.
Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://msgid.link/20240412115729.8316-8-pkshih@realtek.com

drivers/net/wireless/realtek/rtw89/acpi.c

@@ -77,6 +77,50 @@ int rtw89_acpi_dsm_get_policy_6ghz(struct rtw89_dev *rtwdev,
 	return 0;
 }
 
+static bool chk_acpi_policy_6ghz_sp_sig(const struct rtw89_acpi_policy_6ghz_sp *p)
+{
+	return p->signature[0] == 0x52 &&
+	       p->signature[1] == 0x54 &&
+	       p->signature[2] == 0x4B &&
+	       p->signature[3] == 0x07;
+}
+
+static
+int rtw89_acpi_dsm_get_policy_6ghz_sp(struct rtw89_dev *rtwdev,
+				      union acpi_object *obj,
+				      struct rtw89_acpi_policy_6ghz_sp **policy)
+{
+	const struct rtw89_acpi_policy_6ghz_sp *ptr;
+	u32 buf_len;
+
+	if (obj->type != ACPI_TYPE_BUFFER) {
+		rtw89_debug(rtwdev, RTW89_DBG_ACPI,
+			    "acpi: expect buffer but type: %d\n", obj->type);
+		return -EINVAL;
+	}
+
+	buf_len = obj->buffer.length;
+	if (buf_len < sizeof(*ptr)) {
+		rtw89_debug(rtwdev, RTW89_DBG_ACPI, "%s: invalid buffer length: %u\n",
+			    __func__, buf_len);
+		return -EINVAL;
+	}
+
+	ptr = (typeof(ptr))obj->buffer.pointer;
+	if (!chk_acpi_policy_6ghz_sp_sig(ptr)) {
+		rtw89_debug(rtwdev, RTW89_DBG_ACPI, "%s: bad signature\n", __func__);
+		return -EINVAL;
+	}
+
+	*policy = kmemdup(ptr, sizeof(*ptr), GFP_KERNEL);
+	if (!*policy)
+		return -ENOMEM;
+
+	rtw89_hex_dump(rtwdev, RTW89_DBG_ACPI, "policy_6ghz_sp: ", *policy,
+		       sizeof(*ptr));
+	return 0;
+}
+
 int rtw89_acpi_evaluate_dsm(struct rtw89_dev *rtwdev,
 			    enum rtw89_acpi_dsm_func func,
 			    struct rtw89_acpi_dsm_result *res)
@@ -95,6 +139,9 @@ int rtw89_acpi_evaluate_dsm(struct rtw89_dev *rtwdev,
 	if (func == RTW89_ACPI_DSM_FUNC_6G_BP)
 		ret = rtw89_acpi_dsm_get_policy_6ghz(rtwdev, obj,
 						     &res->u.policy_6ghz);
+	else if (func == RTW89_ACPI_DSM_FUNC_6GHZ_SP_SUP)
+		ret = rtw89_acpi_dsm_get_policy_6ghz_sp(rtwdev, obj,
+							&res->u.policy_6ghz_sp);
 	else
 		ret = rtw89_acpi_dsm_get_value(rtwdev, obj, &res->u.value);
 

drivers/net/wireless/realtek/rtw89/acpi.h

@@ -13,6 +13,7 @@ enum rtw89_acpi_dsm_func {
 	RTW89_ACPI_DSM_FUNC_6G_BP = 4,
 	RTW89_ACPI_DSM_FUNC_TAS_EN = 5,
 	RTW89_ACPI_DSM_FUNC_UNII4_SUP = 6,
+	RTW89_ACPI_DSM_FUNC_6GHZ_SP_SUP = 7,
 };
 
 enum rtw89_acpi_conf_unii4 {
@@ -41,11 +42,24 @@ struct rtw89_acpi_policy_6ghz {
 	struct rtw89_acpi_country_code country_list[] __counted_by(country_count);
 } __packed;
 
+enum rtw89_acpi_conf_6ghz_sp {
+	RTW89_ACPI_CONF_6GHZ_SP_US = BIT(0),
+};
+
+struct rtw89_acpi_policy_6ghz_sp {
+	u8 signature[4];
+	u8 revision;
+	u8 override;
+	u8 conf;
+	u8 rsvd;
+} __packed;
+
 struct rtw89_acpi_dsm_result {
 	union {
 		u8 value;
 		/* caller needs to free it after using */
 		struct rtw89_acpi_policy_6ghz *policy_6ghz;
+		struct rtw89_acpi_policy_6ghz_sp *policy_6ghz_sp;
 	} u;
 };