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Commit d06f107b authored by Loic Poulain's avatar Loic Poulain Committed by Marcel Holtmann
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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: default avatarLoic Poulain <loic.poulain@intel.com>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
parent aa655562

drivers/bluetooth/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ menu "Bluetooth device drivers" 


config BT_INTEL

	tristate

	select REGMAP



config BT_BCM

	tristate

drivers/bluetooth/btintel.c

+196 −0
Original line number Diff line number Diff line
@@ -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);

drivers/bluetooth/btintel.h

+9 −0
Original line number Diff line number Diff line
@@ -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