drivers/wifi: Support Drive Strength BRI Rsp Table

Drive Strength BRI Rsp Object provides information from the OEM
platforms if they have replaced the Bluetooth Radio Interface resistor
to overcome the potential STEP errors on their designs. Based on
configuration, CNV firmware shall adjust the BRI Rsp line drive
strength.

The bri_resistor_value is encoded as follow:

|  Bit | Val | Description                                 | Default |
|------+-----+---------------------------------------------+---------|
|    0 |   0 | Device FW default values                    |       1 |
|      |   1 | Override device FW default values           |         |
|  3:1 |   0 | Reserved (shall be set to 0)                |       0 |
|  7:4 |   0 | DSBR override values (only if bit 0 is set) |     0xf |
| 31:7 |   0 | Reserved (shall be set to 0)                |       0 |

Possible values:
- 0xf1 (default): indicates that the resistor on board is 33 Ohm
- 0x0 or 0xb1: indicates that the resistor on board is 10 Ohm

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

BUG=b:346600091
TEST=DSBR methods are added to the wifi device and bluetooth companion
     device and they return the data supplied by the SAR binary blob

Change-Id: Iebe95815c944d045f4cf686abcd1874a8a45e300
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/85017
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

1 files changed, 40 insertions, 2 deletions

diff --git a/src/drivers/wifi/generic/acpi.c b/src/drivers/wifi/generic/acpi.c
index d3277cc1e0..44705535ef 100644
--- a/src/drivers/wifi/generic/acpi.c
+++ b/src/drivers/wifi/generic/acpi.c
@@ -16,8 +16,10 @@
 #include "wifi_private.h"
 
 /* Domain type */
-#define DOMAIN_TYPE_WIFI 0x7
-#define DOMAIN_TYPE_BLUETOOTH 0x12
+enum sar_domain {
+	DOMAIN_TYPE_WIFI = 0x7,
+	DOMAIN_TYPE_BLUETOOTH = 0x12
+};
 
 /* Maximum number DSM UUID bifurcations in _DSM */
 #define MAX_DSM_FUNCS 2
@@ -967,6 +969,40 @@ static void sar_emit_wpfc(const struct wpfc_profile *wpfc)
 	acpigen_write_package_end();
 }
 
+static void sar_emit_dsbr(const struct dsbr_profile *dsbr, enum sar_domain domain)
+{
+	if (dsbr == NULL)
+		return;
+
+	/*
+	 * Name ("DSBR", Package() {
+	 * {
+	 *   Revision,
+	 *   Package()
+	 *   {
+	 *     DomainType,				// 0x7:WiFi
+	 *     BRI Resistor Value			// in Ohm
+	 *   }
+	 } })
+	 */
+	if (dsbr->revision != DSBR_REVISION) {
+		printk(BIOS_ERR, "Unsupported DSBR table revision: %d\n",
+		       dsbr->revision);
+		return;
+	}
+
+	acpigen_write_name("DSBR");
+	acpigen_write_package(2);
+	acpigen_write_dword(dsbr->revision);
+
+	acpigen_write_package(2);
+	acpigen_write_dword(domain);
+	acpigen_write_dword(dsbr->bri_resistor_value);
+
+	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)
 {
@@ -984,6 +1020,7 @@ static void emit_wifi_sar_acpi_structures(const struct device *dev,
 	sar_emit_wtas(sar_limits->wtas);
 	sar_emit_wbem(sar_limits->wbem);
 	sar_emit_wpfc(sar_limits->wpfc);
+	sar_emit_dsbr(sar_limits->dsbr, DOMAIN_TYPE_WIFI);
 }
 
 static void wifi_ssdt_write_device(const struct device *dev, const char *path)
@@ -1107,6 +1144,7 @@ static void wifi_ssdt_write_properties(const struct device *dev, const char *sco
 			sar_emit_bucs(sar_limits.bucs);
 			sar_emit_bdmm(sar_limits.bdmm);
 			sar_emit_ebrd(sar_limits.ebrd);
+			sar_emit_dsbr(sar_limits.dsbr, DOMAIN_TYPE_BLUETOOTH);
 			acpigen_write_scope_end();
 		} else {
 			printk(BIOS_ERR, "Failed to get %s Bluetooth companion ACPI path\n",