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Bluetooth: btintel: Add support to configure TX power
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BRDS - Bluetooth Regulatory Domain Specific absorption rate

Bluetooth has regulatory limitations which prohibit or allow usage of certain
bands or channels as well as limiting Tx power. The Tx power values can be
configured in ACPI table. This patch reads from ACPI entry configures the
controller accordingly.

Signed-off-by: Kiran K <kiran.k@intel.com>
Signed-off-by: Vijay Satija <vijay.satija@intel.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
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Vijay Satija authored and Luiz Augusto von Dentz committed Mar 25, 2025
1 parent 6ac4233 commit e036afb
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333 changes: 333 additions & 0 deletions drivers/bluetooth/btintel.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,11 @@ enum {
DSM_SET_RESET_METHOD = 3,
};

#define BTINTEL_BT_DOMAIN 0x12
#define BTINTEL_SAR_LEGACY 0
#define BTINTEL_SAR_INC_PWR 1
#define BTINTEL_SAR_INC_PWR_SUPPORTED 0

#define CMD_WRITE_BOOT_PARAMS 0xfc0e
struct cmd_write_boot_params {
__le32 boot_addr;
Expand Down Expand Up @@ -2806,6 +2811,331 @@ static int btintel_set_dsbr(struct hci_dev *hdev, struct intel_version_tlv *ver)
return 0;
}

#ifdef CONFIG_ACPI
static acpi_status btintel_evaluate_acpi_method(struct hci_dev *hdev,
acpi_string method,
union acpi_object **ptr,
u8 pkg_size)
{
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object *p;
acpi_status status;
acpi_handle handle;

handle = ACPI_HANDLE(GET_HCIDEV_DEV(hdev));
if (!handle) {
bt_dev_dbg(hdev, "ACPI-BT: No ACPI support for Bluetooth device");
return AE_NOT_EXIST;
}

status = acpi_evaluate_object(handle, method, NULL, &buffer);

if (ACPI_FAILURE(status)) {
bt_dev_dbg(hdev, "ACPI-BT: ACPI Failure: %s method: %s",
acpi_format_exception(status), method);
return status;
}

p = buffer.pointer;

if (p->type != ACPI_TYPE_PACKAGE || p->package.count < pkg_size) {
bt_dev_warn(hdev, "ACPI-BT: Invalid object type: %d or package count: %d",
p->type, p->package.count);
kfree(buffer.pointer);
return AE_ERROR;
}

*ptr = buffer.pointer;
return 0;
}

static union acpi_object *btintel_acpi_get_bt_pkg(union acpi_object *buffer)
{
union acpi_object *domain, *bt_pkg;
int i;

for (i = 1; i < buffer->package.count; i++) {
bt_pkg = &buffer->package.elements[i];
domain = &bt_pkg->package.elements[0];
if (domain->type == ACPI_TYPE_INTEGER &&
domain->integer.value == BTINTEL_BT_DOMAIN)
return bt_pkg;
}
return ERR_PTR(-ENOENT);
}

static int btintel_send_sar_ddc(struct hci_dev *hdev, struct btintel_cp_ddc_write *data, u8 len)
{
struct sk_buff *skb;

skb = __hci_cmd_sync(hdev, 0xfc8b, len, data, HCI_CMD_TIMEOUT);
if (IS_ERR(skb)) {
bt_dev_warn(hdev, "Failed to send sar ddc id:0x%4.4x (%ld)",
le16_to_cpu(data->id), PTR_ERR(skb));
return PTR_ERR(skb);
}
kfree_skb(skb);
return 0;
}

static int btintel_send_edr(struct hci_dev *hdev, struct btintel_cp_ddc_write *cmd,
int id, struct btintel_sar_inc_pwr *sar)
{
cmd->len = 5;
cmd->id = cpu_to_le16(id);
cmd->data[0] = sar->br >> 3;
cmd->data[1] = sar->edr2 >> 3;
cmd->data[2] = sar->edr3 >> 3;
return btintel_send_sar_ddc(hdev, cmd, 6);
}

static int btintel_send_le(struct hci_dev *hdev, struct btintel_cp_ddc_write *cmd,
int id, struct btintel_sar_inc_pwr *sar)
{
cmd->len = 3;
cmd->id = cpu_to_le16(id);
cmd->data[0] = min3(sar->le, sar->le_lr, sar->le_2mhz) >> 3;
return btintel_send_sar_ddc(hdev, cmd, 4);
}

static int btintel_send_br(struct hci_dev *hdev, struct btintel_cp_ddc_write *cmd,
int id, struct btintel_sar_inc_pwr *sar)
{
cmd->len = 3;
cmd->id = cpu_to_le16(id);
cmd->data[0] = sar->br >> 3;
return btintel_send_sar_ddc(hdev, cmd, 4);
}

static int btintel_send_br_mutual(struct hci_dev *hdev, struct btintel_cp_ddc_write *cmd,
int id, struct btintel_sar_inc_pwr *sar)
{
cmd->len = 3;
cmd->id = cpu_to_le16(id);
cmd->data[0] = sar->br;
return btintel_send_sar_ddc(hdev, cmd, 4);
}

static int btintel_send_edr2(struct hci_dev *hdev, struct btintel_cp_ddc_write *cmd,
int id, struct btintel_sar_inc_pwr *sar)
{
cmd->len = 3;
cmd->id = cpu_to_le16(id);
cmd->data[0] = sar->edr2;
return btintel_send_sar_ddc(hdev, cmd, 4);
}

static int btintel_send_edr3(struct hci_dev *hdev, struct btintel_cp_ddc_write *cmd,
int id, struct btintel_sar_inc_pwr *sar)
{
cmd->len = 3;
cmd->id = cpu_to_le16(id);
cmd->data[0] = sar->edr3;
return btintel_send_sar_ddc(hdev, cmd, 4);
}

static int btintel_set_legacy_sar(struct hci_dev *hdev, struct btintel_sar_inc_pwr *sar)
{
struct btintel_cp_ddc_write *cmd;
u8 buffer[64];
int ret;

cmd = (void *)buffer;
ret = btintel_send_br(hdev, cmd, 0x0131, sar);
if (ret)
return ret;

ret = btintel_send_br(hdev, cmd, 0x0132, sar);
if (ret)
return ret;

ret = btintel_send_le(hdev, cmd, 0x0133, sar);
if (ret)
return ret;

ret = btintel_send_edr(hdev, cmd, 0x0137, sar);
if (ret)
return ret;

ret = btintel_send_edr(hdev, cmd, 0x0138, sar);
if (ret)
return ret;

ret = btintel_send_edr(hdev, cmd, 0x013b, sar);
if (ret)
return ret;

ret = btintel_send_edr(hdev, cmd, 0x013c, sar);

return ret;
}

static int btintel_set_mutual_sar(struct hci_dev *hdev, struct btintel_sar_inc_pwr *sar)
{
struct btintel_cp_ddc_write *cmd;
struct sk_buff *skb;
u8 buffer[64];
bool enable;
int ret;

cmd = (void *)buffer;

cmd->len = 3;
cmd->id = cpu_to_le16(0x019e);

if (sar->revision == BTINTEL_SAR_INC_PWR &&
sar->inc_power_mode == BTINTEL_SAR_INC_PWR_SUPPORTED)
cmd->data[0] = 0x01;
else
cmd->data[0] = 0x00;

ret = btintel_send_sar_ddc(hdev, cmd, 4);
if (ret)
return ret;

if (sar->revision == BTINTEL_SAR_INC_PWR &&
sar->inc_power_mode == BTINTEL_SAR_INC_PWR_SUPPORTED) {
cmd->len = 3;
cmd->id = cpu_to_le16(0x019f);
cmd->data[0] = sar->sar_2400_chain_a;

ret = btintel_send_sar_ddc(hdev, cmd, 4);
if (ret)
return ret;
}

ret = btintel_send_br_mutual(hdev, cmd, 0x01a0, sar);
if (ret)
return ret;

ret = btintel_send_edr2(hdev, cmd, 0x01a1, sar);
if (ret)
return ret;

ret = btintel_send_edr3(hdev, cmd, 0x01a2, sar);
if (ret)
return ret;

ret = btintel_send_le(hdev, cmd, 0x01a3, sar);
if (ret)
return ret;

enable = true;
skb = __hci_cmd_sync(hdev, 0xfe25, 1, &enable, HCI_CMD_TIMEOUT);
if (IS_ERR(skb)) {
bt_dev_warn(hdev, "Failed to send Intel SAR Enable (%ld)", PTR_ERR(skb));
return PTR_ERR(skb);
}

kfree_skb(skb);
return 0;
}

static int btintel_sar_send_to_device(struct hci_dev *hdev, struct btintel_sar_inc_pwr *sar,
struct intel_version_tlv *ver)
{
u16 cnvi, cnvr;
int ret;

cnvi = ver->cnvi_top & 0xfff;
cnvr = ver->cnvr_top & 0xfff;

if (cnvi < BTINTEL_CNVI_BLAZARI && cnvr < BTINTEL_CNVR_FMP2) {
bt_dev_info(hdev, "Applying legacy Bluetooth SAR");
ret = btintel_set_legacy_sar(hdev, sar);
} else if (cnvi == BTINTEL_CNVI_GAP || cnvr == BTINTEL_CNVR_FMP2) {
bt_dev_info(hdev, "Applying mutual Bluetooth SAR");
ret = btintel_set_mutual_sar(hdev, sar);
} else {
ret = -EOPNOTSUPP;
}

return ret;
}

static int btintel_acpi_set_sar(struct hci_dev *hdev, struct intel_version_tlv *ver)
{
union acpi_object *bt_pkg, *buffer = NULL;
struct btintel_sar_inc_pwr sar;
acpi_status status;
u8 revision;
int ret;

status = btintel_evaluate_acpi_method(hdev, "BRDS", &buffer, 2);
if (ACPI_FAILURE(status))
return -ENOENT;

bt_pkg = btintel_acpi_get_bt_pkg(buffer);

if (IS_ERR(bt_pkg)) {
ret = PTR_ERR(bt_pkg);
goto error;
}

if (!bt_pkg->package.count) {
ret = -EINVAL;
goto error;
}

revision = buffer->package.elements[0].integer.value;

if (revision > BTINTEL_SAR_INC_PWR) {
bt_dev_dbg(hdev, "BT_SAR: revision: 0x%2.2x not supported", revision);
ret = -EOPNOTSUPP;
goto error;
}

memset(&sar, 0, sizeof(sar));

if (revision == BTINTEL_SAR_LEGACY && bt_pkg->package.count == 8) {
sar.revision = revision;
sar.bt_sar_bios = bt_pkg->package.elements[1].integer.value;
sar.br = bt_pkg->package.elements[2].integer.value;
sar.edr2 = bt_pkg->package.elements[3].integer.value;
sar.edr3 = bt_pkg->package.elements[4].integer.value;
sar.le = bt_pkg->package.elements[5].integer.value;
sar.le_2mhz = bt_pkg->package.elements[6].integer.value;
sar.le_lr = bt_pkg->package.elements[7].integer.value;

} else if (revision == BTINTEL_SAR_INC_PWR && bt_pkg->package.count == 10) {
sar.revision = revision;
sar.bt_sar_bios = bt_pkg->package.elements[1].integer.value;
sar.inc_power_mode = bt_pkg->package.elements[2].integer.value;
sar.sar_2400_chain_a = bt_pkg->package.elements[3].integer.value;
sar.br = bt_pkg->package.elements[4].integer.value;
sar.edr2 = bt_pkg->package.elements[5].integer.value;
sar.edr3 = bt_pkg->package.elements[6].integer.value;
sar.le = bt_pkg->package.elements[7].integer.value;
sar.le_2mhz = bt_pkg->package.elements[8].integer.value;
sar.le_lr = bt_pkg->package.elements[9].integer.value;
} else {
ret = -EINVAL;
goto error;
}

/* Apply only if it is enabled in BIOS */
if (sar.bt_sar_bios != 1) {
bt_dev_dbg(hdev, "Bluetooth SAR is not enabled");
ret = -EOPNOTSUPP;
goto error;
}

ret = btintel_sar_send_to_device(hdev, &sar, ver);
error:
kfree(buffer);
return ret;
}
#endif /* CONFIG_ACPI */

static int btintel_set_specific_absorption_rate(struct hci_dev *hdev,
struct intel_version_tlv *ver)
{
#ifdef CONFIG_ACPI
return btintel_acpi_set_sar(hdev, ver);
#endif
return 0;
}

int btintel_bootloader_setup_tlv(struct hci_dev *hdev,
struct intel_version_tlv *ver)
{
Expand Down Expand Up @@ -2883,6 +3213,9 @@ int btintel_bootloader_setup_tlv(struct hci_dev *hdev,

hci_dev_clear_flag(hdev, HCI_QUALITY_REPORT);

/* Send sar values to controller */
btintel_set_specific_absorption_rate(hdev, ver);

/* Set PPAG feature */
btintel_set_ppag(hdev, ver);

Expand Down
23 changes: 23 additions & 0 deletions drivers/bluetooth/btintel.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -58,6 +58,9 @@ struct intel_tlv {
#define BTINTEL_CNVI_BLAZARU 0x930
#define BTINTEL_CNVI_SCP 0xA00

/* CNVR */
#define BTINTEL_CNVR_FMP2 0x910

#define BTINTEL_IMG_BOOTLOADER 0x01 /* Bootloader image */
#define BTINTEL_IMG_IML 0x02 /* Intermediate image */
#define BTINTEL_IMG_OP 0x03 /* Operational image */
Expand Down Expand Up @@ -165,6 +168,26 @@ struct hci_ppag_enable_cmd {
#define INTEL_TLV_DEBUG_EXCEPTION 0x02
#define INTEL_TLV_TEST_EXCEPTION 0xDE

struct btintel_cp_ddc_write {
u8 len;
__le16 id;
u8 data[];
} __packed;

/* Bluetooth SAR feature (BRDS), Revision 1 */
struct btintel_sar_inc_pwr {
u8 revision;
u32 bt_sar_bios; /* Mode of SAR control to be used, 1:enabled in bios */
u32 inc_power_mode; /* Increased power mode */
u8 sar_2400_chain_a; /* Sar power restriction LB */
u8 br;
u8 edr2;
u8 edr3;
u8 le;
u8 le_2mhz;
u8 le_lr;
};

#define INTEL_HW_PLATFORM(cnvx_bt) ((u8)(((cnvx_bt) & 0x0000ff00) >> 8))
#define INTEL_HW_VARIANT(cnvx_bt) ((u8)(((cnvx_bt) & 0x003f0000) >> 16))
#define INTEL_CNVX_TOP_TYPE(cnvx_top) ((cnvx_top) & 0x00000fff)
Expand Down

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