drivers/wifi: Support Bluetooth Per-Platform Antenna Gain

The ACPI BPAG method provide information to controls the antenna gain
method to be used per country.

The antenna gain mode is a bit field (0 - disabled, 1 -enabled)
defined as follow:
- Bit 0 - Antenna gain in EU
- Bit 1 - Antenna gain in China Mainland

The implementation follows document 559910 Intel Connectivity
Platforms BIOS Guideline revision 9.2 specification.

BUG=b:346600091
TEST=BPAG method is added to the bluetooth companion device and return
     the data supplied by the SAR binary blob

Change-Id: Iebe95815c944d045f4cf686abcd1874a8a45e210
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/84941
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>

3 files changed, 53 insertions, 1 deletions

diff --git a/src/drivers/wifi/generic/acpi.c b/src/drivers/wifi/generic/acpi.c
index 9ed17e0b5c..0a5bee728f 100644
--- a/src/drivers/wifi/generic/acpi.c
+++ b/src/drivers/wifi/generic/acpi.c
@@ -666,6 +666,41 @@ static void sar_emit_wbem(const struct wbem_profile *wbem)
 	acpigen_write_package_end();
 }
 
+static void sar_emit_bpag(const struct bpag_profile *bpag)
+{
+	if (bpag == NULL)
+		return;
+
+	/*
+	 * Name ("BPAG", Package () {
+	 *   Revision,
+	 *   Package () {
+	 *     Domain Type,			// 0x12:Bluetooth
+	 *     Bluetooth Per-Platform Antenna Gain Mode
+	 *   }
+	 * })
+	 */
+	if (bpag->revision == 0 || bpag->revision > BPAG_REVISION) {
+		printk(BIOS_ERR, "Unsupported BPAG table revision: %d\n",
+		       bpag->revision);
+		return;
+	}
+
+	acpigen_write_name("BPAG");
+	acpigen_write_package(2);
+	acpigen_write_dword(bpag->revision);
+
+	/*
+	 * Emit 'Domain Type' + 'Antenna Gain Mode'
+	 */
+	acpigen_write_package(2);
+	acpigen_write_dword(DOMAIN_TYPE_BLUETOOTH);
+	acpigen_write_dword(bpag->antenna_gain_country_enablement);
+
+	acpigen_write_package_end();
+	acpigen_write_package_end();
+}
+
 static void emit_wifi_sar_acpi_structures(const struct device *dev,
 					  union wifi_sar_limits *sar_limits)
 {
@@ -798,6 +833,7 @@ static void wifi_ssdt_write_properties(const struct device *dev, const char *sco
 		if (path) {	/* Bluetooth device under USB Hub scope or PCIe root port */
 			acpigen_write_scope(path);
 			sar_emit_brds(sar_limits.bsar);
+			sar_emit_bpag(sar_limits.bpag);
 			acpigen_write_scope_end();
 		} else {
 			printk(BIOS_ERR, "Failed to get %s Bluetooth companion ACPI path\n",
diff --git a/src/include/sar.h b/src/include/sar.h
index b0274b501a..b9c83c3a05 100644
--- a/src/include/sar.h
+++ b/src/include/sar.h
@@ -9,10 +9,11 @@
 #define MAX_DENYLIST_ENTRY	16
 #define MAX_DSAR_SET_COUNT	3
 #define MAX_GEO_OFFSET_REVISION	3
-#define MAX_PROFILE_COUNT	7
+#define MAX_PROFILE_COUNT	8
 #define MAX_SAR_REVISION	2
 #define BSAR_REVISION		1
 #define WBEM_REVISION		0
+#define BPAG_REVISION		2
 #define REVISION_SIZE		1
 #define SAR_REV0_CHAINS_COUNT	2
 #define SAR_REV0_SUBBANDS_COUNT	5
@@ -81,6 +82,11 @@ struct wbem_profile {
 	uint32_t bandwidth_320mhz_country_enablement;
 } __packed;
 
+struct bpag_profile {
+	uint8_t revision;
+	uint32_t antenna_gain_country_enablement;
+} __packed;
+
 struct sar_header {
 	char marker[SAR_STR_PREFIX_SIZE];
 	uint8_t version;
@@ -97,6 +103,7 @@ union wifi_sar_limits {
 		struct dsm_profile *dsm;
 		struct bsar_profile *bsar;
 		struct wbem_profile *wbem;
+		struct bpag_profile *bpag;
 	};
 	void *profile[MAX_PROFILE_COUNT];
 };
diff --git a/src/vendorcode/google/chromeos/sar.c b/src/vendorcode/google/chromeos/sar.c
index e8d4410f4b..dcf647398e 100644
--- a/src/vendorcode/google/chromeos/sar.c
+++ b/src/vendorcode/google/chromeos/sar.c
@@ -110,6 +110,14 @@ static size_t wbem_table_size(const struct wbem_profile *wbem)
 	return sizeof(struct wbem_profile);
 }
 
+static size_t bpag_table_size(const struct bpag_profile *bpag)
+{
+	if (bpag == NULL)
+		return 0;
+
+	return sizeof(struct bpag_profile);
+}
+
 static bool valid_legacy_length(size_t bin_len)
 {
 	if (bin_len == LEGACY_SAR_WGDS_BIN_SIZE)
@@ -163,6 +171,7 @@ static int fill_wifi_sar_limits(union wifi_sar_limits *sar_limits, const uint8_t
 	expected_sar_bin_size += dsm_table_size(sar_limits->dsm);
 	expected_sar_bin_size += bsar_table_size(sar_limits->bsar);
 	expected_sar_bin_size += wbem_table_size(sar_limits->wbem);
+	expected_sar_bin_size += bpag_table_size(sar_limits->bpag);
 
 	if (sar_bin_size != expected_sar_bin_size) {
 		printk(BIOS_ERR, "Invalid SAR size, expected: %zu, obtained: %zu\n",