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Bluetooth: btintel: Add iBT register access over HCI support 

Add regmap ibt to support Intel Bluetooth silicon register access
over HCI. Intel BT/FM combo chip allows to read/write some registers
(e.g. FM registers) via its HCI interface.

Read/Write operations are performed via a HCI transaction composed of
a HCI command (host->controller) followed by a HCI command complete
event (controller->host). Read/Write Command opcodes can be specified
to the regmap init function.
We define data formats which are intel/vendor specific.

Register Read/Write HCI command payload (Host):
Field: | REG ADDR | MODE | DATA_LEN | DATA... |
size:  |   32b    |  8b  |    8b    |  8b*    |

Register Read HCI command complete event payload (Controller):
Field: | CMD STATUS | REG ADDR | DATA... |
size:  |     8b     |   32b    |  8b*    |

Register Write HCI command complete event payload (Controller):
Field: | CMD_STATUS |
size:  |     8b     |

Since this payload is HCI encapsulated, Little Endian byte order is
used.

Write/Read Example:

If we write 0x0000002a at address 0x00008c04, with opcode_write 0xfc5d,
The resulting transaction is (btmon trace):

< HCI Command (0x3f|0x005d) plen 10 [hci0]
        04 8c 00 00 02 04 2a 00 00 00
> HCI Event (0x0e) plen 4
      Unknown (0x3f|0x005d) ncmd 1
        00

Then, if we read the same register with opcode_read 0xfc5e:

< HCI Command (0x3f|0x005e) plen 6 [hci0]
        04 8c 00 00 02 04
> HCI Event (0x0e) plen 12 [hci0]
      Unknown (0x3f|0x005e) ncmd 1
        00 04 8c 00 00 2a 00 00 00

Signed-off-by: Loic Poulain <loic.poulain@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This commit is contained in:
Loic Poulain 2015-10-01 18:16:21 +02:00 committed by Marcel Holtmann
parent aa6555622c
commit d06f107bcd
3 changed files with 206 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/bluetooth/Kconfig
View File

@ -4,6 +4,7 @@ menu "Bluetooth device drivers"
config BT_INTEL
tristate
select REGMAP
config BT_BCM
tristate

196
drivers/bluetooth/btintel.c
View File

@ -23,6 +23,7 @@
#include <linux/module.h>
#include <linux/firmware.h>
#include <linux/regmap.h>
#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
@ -215,6 +216,201 @@ int btintel_load_ddc_config(struct hci_dev *hdev, const char *ddc_name)
}
EXPORT_SYMBOL_GPL(btintel_load_ddc_config);
/* ------- REGMAP IBT SUPPORT ------- */
#define IBT_REG_MODE_8BIT 0x00
#define IBT_REG_MODE_16BIT 0x01
#define IBT_REG_MODE_32BIT 0x02
struct regmap_ibt_context {
struct hci_dev *hdev;
__u16 op_write;
__u16 op_read;
};
struct ibt_cp_reg_access {
__le32 addr;
__u8 mode;
__u8 len;
__u8 data[0];
} __packed;
struct ibt_rp_reg_access {
__u8 status;
__le32 addr;
__u8 data[0];
} __packed;
static int regmap_ibt_read(void *context, const void *addr, size_t reg_size,
void *val, size_t val_size)
{
struct regmap_ibt_context *ctx = context;
struct ibt_cp_reg_access cp;
struct ibt_rp_reg_access *rp;
struct sk_buff *skb;
int err = 0;
if (reg_size != sizeof(__le32))
return -EINVAL;
switch (val_size) {
case 1:
cp.mode = IBT_REG_MODE_8BIT;
break;
case 2:
cp.mode = IBT_REG_MODE_16BIT;
break;
case 4:
cp.mode = IBT_REG_MODE_32BIT;
break;
default:
return -EINVAL;
}
/* regmap provides a little-endian formatted addr */
cp.addr = *(__le32 *)addr;
cp.len = val_size;
bt_dev_dbg(ctx->hdev, "Register (0x%x) read", le32_to_cpu(cp.addr));
skb = hci_cmd_sync(ctx->hdev, ctx->op_read, sizeof(cp), &cp,
HCI_CMD_TIMEOUT);
if (IS_ERR(skb)) {
err = PTR_ERR(skb);
bt_dev_err(ctx->hdev, "regmap: Register (0x%x) read error (%d)",
le32_to_cpu(cp.addr), err);
return err;
}
if (skb->len != sizeof(*rp) + val_size) {
bt_dev_err(ctx->hdev, "regmap: Register (0x%x) read error, bad len",
le32_to_cpu(cp.addr));
err = -EINVAL;
goto done;
}
rp = (struct ibt_rp_reg_access *)skb->data;
if (rp->addr != cp.addr) {
bt_dev_err(ctx->hdev, "regmap: Register (0x%x) read error, bad addr",
le32_to_cpu(rp->addr));
err = -EINVAL;
goto done;
}
memcpy(val, rp->data, val_size);
done:
kfree_skb(skb);
return err;
}
static int regmap_ibt_gather_write(void *context,
const void *addr, size_t reg_size,
const void *val, size_t val_size)
{
struct regmap_ibt_context *ctx = context;
struct ibt_cp_reg_access *cp;
struct sk_buff *skb;
int plen = sizeof(*cp) + val_size;
u8 mode;
int err = 0;
if (reg_size != sizeof(__le32))
return -EINVAL;
switch (val_size) {
case 1:
mode = IBT_REG_MODE_8BIT;
break;
case 2:
mode = IBT_REG_MODE_16BIT;
break;
case 4:
mode = IBT_REG_MODE_32BIT;
break;
default:
return -EINVAL;
}
cp = kmalloc(plen, GFP_KERNEL);
if (!cp)
return -ENOMEM;
/* regmap provides a little-endian formatted addr/value */
cp->addr = *(__le32 *)addr;
cp->mode = mode;
cp->len = val_size;
memcpy(&cp->data, val, val_size);
bt_dev_dbg(ctx->hdev, "Register (0x%x) write", le32_to_cpu(cp->addr));
skb = hci_cmd_sync(ctx->hdev, ctx->op_write, plen, cp, HCI_CMD_TIMEOUT);
if (IS_ERR(skb)) {
err = PTR_ERR(skb);
bt_dev_err(ctx->hdev, "regmap: Register (0x%x) write error (%d)",
le32_to_cpu(cp->addr), err);
goto done;
}
kfree_skb(skb);
done:
kfree(cp);
return err;
}
static int regmap_ibt_write(void *context, const void *data, size_t count)
{
/* data contains register+value, since we only support 32bit addr,
* minimum data size is 4 bytes.
*/
if (WARN_ONCE(count < 4, "Invalid register access"))
return -EINVAL;
return regmap_ibt_gather_write(context, data, 4, data + 4, count - 4);
}
static void regmap_ibt_free_context(void *context)
{
kfree(context);
}
static struct regmap_bus regmap_ibt = {
.read = regmap_ibt_read,
.write = regmap_ibt_write,
.gather_write = regmap_ibt_gather_write,
.free_context = regmap_ibt_free_context,
.reg_format_endian_default = REGMAP_ENDIAN_LITTLE,
.val_format_endian_default = REGMAP_ENDIAN_LITTLE,
};
/* Config is the same for all register regions */
static const struct regmap_config regmap_ibt_cfg = {
.name = "btintel_regmap",
.reg_bits = 32,
.val_bits = 32,
};
struct regmap *btintel_regmap_init(struct hci_dev *hdev, u16 opcode_read,
u16 opcode_write)
{
struct regmap_ibt_context *ctx;
bt_dev_info(hdev, "regmap: Init R%x-W%x region", opcode_read,
opcode_write);
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return ERR_PTR(-ENOMEM);
ctx->op_read = opcode_read;
ctx->op_write = opcode_write;
ctx->hdev = hdev;
return regmap_init(&hdev->dev, &regmap_ibt, ctx, &regmap_ibt_cfg);
}
EXPORT_SYMBOL_GPL(btintel_regmap_init);
MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
MODULE_DESCRIPTION("Bluetooth support for Intel devices ver " VERSION);
MODULE_VERSION(VERSION);

9
drivers/bluetooth/btintel.h
View File

@ -80,6 +80,9 @@ int btintel_secure_send(struct hci_dev *hdev, u8 fragment_type, u32 plen,
const void *param);
int btintel_load_ddc_config(struct hci_dev *hdev, const char *ddc_name);
struct regmap *btintel_regmap_init(struct hci_dev *hdev, u16 opcode_read,
u16 opcode_write);
#else
static inline int btintel_check_bdaddr(struct hci_dev *hdev)
@ -113,4 +116,10 @@ static inline int btintel_load_ddc_config(struct hci_dev *hdev,
return -EOPNOTSUPP;
}
static inline struct regmap *btintel_regmap_init(struct hci_dev *hdev,
u16 opcode_read,
u16 opcode_write)
{
return ERR_PTR(-EINVAL);
}
#endif