wifi: Add support for per-platform antenna gain

Add support for the PPAG ACPI BIOS configuration table as per the
connectivity document:
559910_Intel_Connectivity_Platforms_BIOS_Guidelines_Rev6_4.pdf

BUG=b:193665559
TEST=Generated SAR file with the PPAG related configuration values and
verified that the SSDT has the PPAG ACPI table.

Change-Id: Ie8d25113feeeb4a4242cfd7d72a5091d2d5fb389
Signed-off-by: Sugnan Prabhu S <sugnan.prabhu.s@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/57060
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>

src/drivers/wifi/generic/acpi.c

@@ -42,6 +42,13 @@ static const uint8_t *wgds_fetch_set(struct geo_profile *wgds, size_t set_num)
 	return wgds_table + (wgds->bands_count * set_num);
 }
 
+static const uint8_t *ppag_fetch_set(struct gain_profile *ppag, size_t set_num)
+{
+	const uint8_t *ppag_table = &ppag->ppag_table[0];
+
+	return ppag_table + (ppag->bands_count * set_num);
+}
+
 static void sar_emit_wrds(const struct sar_profile *sar)
 {
 	int i;
@@ -216,6 +223,50 @@ static void sar_emit_wgds(struct geo_profile *wgds)
 	acpigen_write_package_end();
 }
 
+static void sar_emit_ppag(struct gain_profile *ppag)
+{
+	int i;
+	size_t package_size, set_num;
+	const uint8_t *set;
+
+	if (ppag == NULL)
+		return;
+
+	/*
+	 * Name ("PPAG", Package () {
+	 *   Revision,
+	 *   Package () {
+	 *     Domain Type,		// 0x7:WiFi
+	 *     PPAG Mode,		// Defines the mode of ANT_gain control to be used
+	 *     ANT_gain Table Chain A	// Defines the ANT_gain in dBi for chain A
+	 *     ANT_gain Table Chain B	// Defines the ANT_gain in dBi for chain B
+	 *   }
+	 * })
+	 */
+	if (ppag->revision > MAX_ANT_GAINS_REVISION) {
+		printk(BIOS_ERR, "Invalid PPAG revision: %d\n", ppag->revision);
+		return;
+	}
+
+	package_size = 1 + 1 + ppag->chains_count * ppag->bands_count;
+
+	acpigen_write_name("PPAG");
+	acpigen_write_package(2);
+	acpigen_write_dword(ppag->revision);
+	acpigen_write_package(package_size);
+	acpigen_write_dword(DOMAIN_TYPE_WIFI);
+	acpigen_write_dword(ppag->mode);
+
+	for (set_num = 0; set_num < ppag->chains_count; set_num++) {
+		set = ppag_fetch_set(ppag, set_num);
+		for (i = 0; i < ppag->bands_count; i++)
+			acpigen_write_byte(set[i]);
+	}
+
+	acpigen_write_package_end();
+	acpigen_write_package_end();
+}
+
 static void emit_sar_acpi_structures(const struct device *dev)
 {
 	union wifi_sar_limits sar_limits;
@@ -236,6 +287,7 @@ static void emit_sar_acpi_structures(const struct device *dev)
 	sar_emit_wrds(sar_limits.sar);
 	sar_emit_ewrd(sar_limits.sar);
 	sar_emit_wgds(sar_limits.wgds);
+	sar_emit_ppag(sar_limits.ppag);
 
 	free(sar_limits.sar);
 }

src/include/sar.h

@@ -4,9 +4,10 @@
 
 #include <stdint.h>
 
+#define MAX_ANT_GAINS_REVISION	2
 #define MAX_DSAR_SET_COUNT	3
 #define MAX_GEO_OFFSET_REVISION	3
-#define MAX_PROFILE_COUNT	2
+#define MAX_PROFILE_COUNT	3
 #define MAX_SAR_REVISION	2
 #define REVISION_SIZE		1
 #define SAR_REV0_CHAINS_COUNT	2
@@ -30,6 +31,14 @@ struct sar_profile {
 	uint8_t sar_table[0];
 } __packed;
 
+struct gain_profile {
+	uint8_t revision;
+	uint8_t mode;
+	uint8_t chains_count;
+	uint8_t bands_count;
+	uint8_t ppag_table[0];
+} __packed;
+
 struct sar_header {
 	char marker[SAR_STR_PREFIX_SIZE];
 	uint8_t version;
@@ -41,6 +50,7 @@ union wifi_sar_limits {
 	struct {
 		struct sar_profile *sar;
 		struct geo_profile *wgds;
+		struct gain_profile *ppag;
 	};
 	void *profile[MAX_PROFILE_COUNT];
 };

src/vendorcode/google/chromeos/sar.c

@@ -68,6 +68,14 @@ static int wgds_table_size(const struct geo_profile *geo)
 	return sizeof(struct geo_profile) + (geo->chains_count * geo->bands_count);
 }
 
+static int gain_table_size(const struct gain_profile *gain)
+{
+	if (gain == NULL)
+		return 0;
+
+	return sizeof(struct gain_profile) + (gain->chains_count * gain->bands_count);
+}
+
 static bool valid_legacy_length(size_t bin_len)
 {
 	if (bin_len == LEGACY_SAR_WGDS_BIN_SIZE)
@@ -116,6 +124,7 @@ static int fill_wifi_sar_limits(union wifi_sar_limits *sar_limits, const uint8_t
 	expected_sar_bin_size = header_size;
 	expected_sar_bin_size += sar_table_size(sar_limits->sar);
 	expected_sar_bin_size += wgds_table_size(sar_limits->wgds);
+	expected_sar_bin_size += gain_table_size(sar_limits->ppag);
 
 	if (sar_bin_size != expected_sar_bin_size) {
 		printk(BIOS_ERR, "ERROR: Invalid SAR size, expected: %ld, obtained: %ld\n",
@@ -178,6 +187,7 @@ static int fill_wifi_sar_limits_legacy(union wifi_sar_limits *sar_limits,
  * Offsets
  * [SAR_REVISION,DSAR_SET_COUNT,CHAINS_COUNT,SUBBANDS_COUNT <WRDD>[EWRD]]
  * [WGDS_REVISION,CHAINS_COUNT,SUBBANDS_COUNT<WGDS_DATA>]
+ * [PPAG_REVISION,MODE,CHAINS_COUNT,SUBBANDS_COUNT<PPAG_DATA>]
  *
  * The configuration data will always have the revision added in the file for each of the
  * block, based on the revision number and validity, size of the specific block will be
@@ -195,6 +205,23 @@ static int fill_wifi_sar_limits_legacy(union wifi_sar_limits *sar_limits,
  * [GROUP#0] is for FCC
  * [GROUP#1] is for Europe/Japan
  * [GROUP#2] is for ROW
+ *
+ * [PPAG_DATA] = [ANT_gain Table Chain A] [ANT_gain Table Chain A]
+ *
+ * [ANT_gain Table] =
+ *	Supported by Revision 0, 1 and 2
+ *              [Antenna gain used for 2400MHz frequency]
+ *              [Antenna gain used for 5150-5350MHz frequency]
+ *              [Antenna gain used for 5350-5470MHz frequency]
+ *              [Antenna gain used for 5470-5725MHz frequency]
+ *              [Antenna gain used for 5725-5945MHz frequency]
+ *	Supported by Revision 1 and 2
+ *              [Antenna gain used for 5945-6165MHz frequency]
+ *              [Antenna gain used for 6165-6405MHz frequency]
+ *              [Antenna gain used for 6405-6525MHz frequency]
+ *              [Antenna gain used for 6525-6705MHz frequency]
+ *              [Antenna gain used for 6705-6865MHz frequency]
+ *              [Antenna gain used for 6865-7105MHz frequency]
  */
 int get_wifi_sar_limits(union wifi_sar_limits *sar_limits)
 {