Hi Kiran,
On Thu, Jun 20, 2024 at 10:52 AM Kiran K <kiran.k@xxxxxxxxx> wrote:
>
> 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 | 115 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 115 insertions(+)
>
> diff --git a/drivers/bluetooth/btintel.c b/drivers/bluetooth/btintel.c
> index 5d735391545a..1d6586b30c8d 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 +51,39 @@ 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)
> +{
> +#if defined(CONFIG_EFI)
iirc IS_ENABLED is normally preferred over #if defined, well except if
you have undefined symbols but that usually indicates the APIs have
not been done with usage of IS_ENABLED in mind.
> + void *data;
> + efi_status_t status;
> + size_t data_size = 0;
> +
> + 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;
> +#else
> + return ERR_PTR(-EOPNOTSUPP);
> +#endif
> +}
> +
> int btintel_check_bdaddr(struct hci_dev *hdev)
> {
> struct hci_rp_read_bd_addr *bda;
> @@ -2615,6 +2650,80 @@ 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 +2758,12 @@ 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
>
>
--
Luiz Augusto von Dentz
