BRI (Bluetooth Radio Interface) traffic from CNVr to CNVi was found
causing cross talk step errors to WiFi. As a workaround, driver needs to
reduce the drive strength of BRI. During *setup*, driver reads the drive
strength value from efi variable and passes it controller via vendor
specific command with opcode 0xfc0a.
Signed-off-by: Kiran K <kiran.k@xxxxxxxxx>
---
drivers/bluetooth/btintel.c | 114 ++++++++++++++++++++++++++++++++++++
1 file changed, 114 insertions(+)
diff --git a/drivers/bluetooth/btintel.c b/drivers/bluetooth/btintel.c
index 5d735391545a..3dc557aac43d 100644
--- a/drivers/bluetooth/btintel.c
+++ b/drivers/bluetooth/btintel.c
@@ -12,6 +12,8 @@
#include <linux/acpi.h>
#include <acpi/acpi_bus.h>
#include <asm/unaligned.h>
+#include <linux/efi.h>
+
#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
@@ -49,6 +51,38 @@ static const guid_t btintel_guid_dsm =
GUID_INIT(0xaa10f4e0, 0x81ac, 0x4233,
0xab, 0xf6, 0x3b, 0x2a, 0xc5, 0x0e, 0x28, 0xd9);
+static void *btintel_uefi_get_variable(efi_char16_t *name, efi_guid_t *guid)
+{
+ void *data;
+ efi_status_t status;
+ size_t data_size = 0;
+
+ if (!IS_ENABLED(CONFIG_EFI))
+ return ERR_PTR(-EOPNOTSUPP);
+
+ if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE))
+ return ERR_PTR(-EOPNOTSUPP);
+
+ status = efi.get_variable(name, guid, NULL, &data_size, NULL);
+
+ if (status != EFI_BUFFER_TOO_SMALL || !data_size)
+ return ERR_PTR(-EIO);
+
+ data = kmalloc(data_size, GFP_KERNEL);
+
+ if (!data)
+ return ERR_PTR(-ENOMEM);
+
+ status = efi.get_variable(name, guid, NULL, &data_size, data);
+
+ if (status != EFI_SUCCESS) {
+ kfree(data);
+ return ERR_PTR(-ENXIO);
+ }
+
+ return data;
+}
+
int btintel_check_bdaddr(struct hci_dev *hdev)
{
struct hci_rp_read_bd_addr *bda;
@@ -2615,6 +2649,80 @@ static u8 btintel_classify_pkt_type(struct hci_dev *hdev, struct sk_buff *skb)
return hci_skb_pkt_type(skb);
}
+static int btintel_set_dsbr(struct hci_dev *hdev, struct intel_version_tlv *ver)
+{
+ struct btintel_dsbr_cmd {
+ u8 enable;
+ u8 dsbr;
+ } __packed;
+
+ struct btintel_dsbr {
+ u8 header;
+ u32 dsbr;
+ } __packed;
+
+ struct btintel_dsbr *dsbr;
+ struct btintel_dsbr_cmd cmd;
+ struct sk_buff *skb;
+ u8 status;
+ efi_guid_t guid = EFI_GUID(0xe65d8884, 0xd4af, 0x4b20, 0x8d, 0x03,
+ 0x77, 0x2e, 0xcc, 0x3d, 0xa5, 0x31);
+
+ memset(&cmd, 0, sizeof(cmd));
+ dsbr = btintel_uefi_get_variable(L"UefiCnvCommonDSBR", &guid);
+ if (IS_ERR(dsbr)) {
+ /* If efi variable is not present, driver still needs to send
+ * 0xfc0a command with default values
+ */
+ bt_dev_dbg(hdev, "Error reading efi DSBR (%ld)",
+ PTR_ERR(dsbr));
+ dsbr = NULL;
+ }
+
+ if (dsbr) {
+ /* bit0: 0 - Use firmware default value
+ * 1 - Override firmware value
+ * bit3:1 - Reserved
+ * bit7:4 - DSBR override values
+ * bt31:7 - Reserved
+ */
+ cmd.enable = dsbr->dsbr & BIT(0);
+ if (cmd.enable)
+ cmd.dsbr = dsbr->dsbr >> 4 & 0xF;
+ kfree(dsbr);
+ }
+
+ bt_dev_info(hdev, "dsbr: enabled: 0x%2.2x value: 0x%2.2x", cmd.enable,
+ cmd.dsbr);
+
+ skb = __hci_cmd_sync(hdev, 0xfc0a, sizeof(cmd), &cmd, HCI_CMD_TIMEOUT);
+ if (IS_ERR(skb)) {
+ bt_dev_err(hdev, "Failed to send Intel DSBR command (%ld)",
+ PTR_ERR(skb));
+ return -bt_to_errno(PTR_ERR(skb));
+ }
+
+ status = skb->data[0];
+ kfree_skb(skb);
+
+ if (status) {
+ bt_dev_err(hdev, "Set DSBR failed 0x%2.2x", status);
+ return -bt_to_errno(status);
+ }
+ return 0;
+}
+
+static int btintel_apply_dsbr(struct hci_dev *hdev,
+ struct intel_version_tlv *ver)
+{
+ /* For BlazarI + B0 step, DSBR command needs to be sent just after
+ * downloading IML firmware
+ */
+ return ver->img_type == BTINTEL_IMG_IML &&
+ ((ver->cnvi_top & 0xfff) == BTINTEL_CNVI_BLAZARI) &&
+ INTEL_CNVX_TOP_STEP(ver->cnvi_top) == 0x01;
+}
+
int btintel_bootloader_setup_tlv(struct hci_dev *hdev,
struct intel_version_tlv *ver)
{
@@ -2649,6 +2757,12 @@ int btintel_bootloader_setup_tlv(struct hci_dev *hdev,
if (err)
return err;
+ if (btintel_apply_dsbr(hdev, ver)) {
+ err = btintel_set_dsbr(hdev, ver);
+ if (err)
+ return err;
+ }
+
/* If image type returned is BTINTEL_IMG_IML, then controller supports
* intermediae loader image
*/
--
2.40.1
