Add support for 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 <[email protected]>
---
v2: Change "hci" to "ibt" since it's intel specific
Add comments for clarification
Remove unjustified default opcodes
Protect __hci_cmd_sync call with hdev req_lock
Replace BUG_ON with WARN_ONCE
v3: Use thread-safe hci_cmd_sync instead of __hci_cmd_sync
Update subject
drivers/base/regmap/Kconfig | 6 +-
drivers/base/regmap/Makefile | 1 +
drivers/base/regmap/regmap-ibt.c | 276 +++++++++++++++++++++++++++++++++++++++
include/linux/regmap.h | 7 +
4 files changed, 289 insertions(+), 1 deletion(-)
create mode 100644 drivers/base/regmap/regmap-ibt.c
diff --git a/drivers/base/regmap/Kconfig b/drivers/base/regmap/Kconfig
index db9d00c3..e34675f 100644
--- a/drivers/base/regmap/Kconfig
+++ b/drivers/base/regmap/Kconfig
@@ -3,7 +3,7 @@
# subsystems should select the appropriate symbols.
config REGMAP
- default y if (REGMAP_I2C || REGMAP_SPI || REGMAP_SPMI || REGMAP_AC97 ||
REGMAP_MMIO || REGMAP_IRQ)
+ default y if (REGMAP_I2C || REGMAP_SPI || REGMAP_SPMI || REGMAP_AC97 ||
REGMAP_MMIO || REGMAP_IRQ || REGMAP_IBT)
select LZO_COMPRESS
select LZO_DECOMPRESS
select IRQ_DOMAIN if REGMAP_IRQ
@@ -29,3 +29,7 @@ config REGMAP_MMIO
config REGMAP_IRQ
bool
+
+config REGMAP_IBT
+ tristate
+ depends on BT
\ No newline at end of file
diff --git a/drivers/base/regmap/Makefile b/drivers/base/regmap/Makefile
index 609e4c8..e7fd73f 100644
--- a/drivers/base/regmap/Makefile
+++ b/drivers/base/regmap/Makefile
@@ -10,3 +10,4 @@ obj-$(CONFIG_REGMAP_SPI) += regmap-spi.o
obj-$(CONFIG_REGMAP_SPMI) += regmap-spmi.o
obj-$(CONFIG_REGMAP_MMIO) += regmap-mmio.o
obj-$(CONFIG_REGMAP_IRQ) += regmap-irq.o
+obj-$(CONFIG_REGMAP_IBT) += regmap-ibt.o
diff --git a/drivers/base/regmap/regmap-ibt.c b/drivers/base/regmap/regmap-ibt.c
new file mode 100644
index 0000000..bfa0c50
--- /dev/null
+++ b/drivers/base/regmap/regmap-ibt.c
@@ -0,0 +1,276 @@
+/*
+ * Register map access API - iBT support
+ *
+ * Copyright 2015 Intel Corporation
+ *
+ * Author: Loic Poulain <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/regmap.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>
+
+#include "internal.h"
+
+#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;
+};
+
+/**
+ * HCI Command payload for register read/write
+ *
+ * @raddr: Register address (32bit only)
+ * @mode: Value access mode (8bit, 16bit, 32bit)
+ * @len: Data len to read/write
+ * @data: Data to write
+ */
+struct ibt_cp_reg_access {
+ __le32 addr;
+ __u8 mode;
+ __u8 len;
+ __u8 data[0];
+} __packed;
+
+/**
+ * HCI Command Complete Event payload for register read
+ *
+ * @status: cmd read status
+ * @addr: Register address (32bit only)
+ * @data: Register value
+ */
+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)) {
+ bt_dev_err(ctx->hdev, "regmap: Register (0x%x) read error
(%ld)",
+ le32_to_cpu(cp.addr), PTR_ERR(skb));
+ return PTR_ERR(skb);
+ }
+
+ 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)) {
+ bt_dev_err(ctx->hdev, "regmap: Register (0x%x) write error
(%ld)",
+ le32_to_cpu(cp->addr), PTR_ERR(skb));
+ err = PTR_ERR(skb);
+ 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,
+};
+
+static struct regmap *__regmap_init_ibt(struct hci_dev *hdev,
+ u16 opcode_read, u16 opcode_write,
+ const struct regmap_config *config,
+ bool devm)
+{
+ struct regmap_ibt_context *ctx;
+
+ if (!config)
+ return ERR_PTR(-EINVAL);
+
+ bt_dev_info(hdev, "regmap: Init %s-R%x-W%x region", config->name,
+ opcode_read, opcode_write);
+
+ if (config->reg_bits != 32) {
+ bt_dev_err(hdev, "regmap: Unsupported address size: %d",
+ config->reg_bits);
+ return ERR_PTR(-EINVAL);
+ }
+
+ 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;
+
+ if (devm)
+ return devm_regmap_init(&hdev->dev, ®map_ibt, ctx, config);
+ else
+ return regmap_init(&hdev->dev, ®map_ibt, ctx, config);
+}
+
+/**
+ * regmap_init_ibt(): Initialize register map
+ *
+ * @hdev: HCI Device that will be interacted with
+ * @config: Configuration for register map
+ * @opcode_read: HCI opcode command for register-read operation
+ * @opcode_write: HCI opcode command for register-write operation
+ *
+ * The return value will be an ERR_PTR() on error or a valid pointer to
+ * a struct regmap.
+ */
+struct regmap *regmap_init_ibt(struct hci_dev *hdev,
+ u16 opcode_read, u16 opcode_write,
+ const struct regmap_config *config)
+{
+ return __regmap_init_ibt(hdev, opcode_read, opcode_write, config,
+ false);
+}
+EXPORT_SYMBOL_GPL(regmap_init_ibt);
+
+/**
+ * devm_regmap_init_ibt(): Initialize register map
+ *
+ * @hdev: HCI Device that will be interacted with
+ * @config: Configuration for register map
+ * @opcode_read: HCI opcode command for register-read operation
+ * @opcode_write: HCI opcode command for register-write operation
+ *
+ * The return value will be an ERR_PTR() on error or a valid pointer
+ * to a struct regmap. The regmap will be automatically freed by the
+ * device management code.
+ */
+struct regmap *devm_regmap_init_ibt(struct hci_dev *hdev,
+ u16 opcode_read, u16 opcode_write,
+ const struct regmap_config *config)
+{
+ return __regmap_init_ibt(hdev, opcode_read, opcode_write, config,
+ true);
+}
+EXPORT_SYMBOL_GPL(devm_regmap_init_ibt);
+
+MODULE_LICENSE("GPL");
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 59c55ea..af7c146 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -28,6 +28,7 @@ struct regmap;
struct regmap_range_cfg;
struct regmap_field;
struct snd_ac97;
+struct hci_dev;
/* An enum of all the supported cache types */
enum regcache_type {
@@ -343,6 +344,9 @@ struct regmap *regmap_init_mmio_clk(struct device *dev,
const char *clk_id,
const struct regmap_config *config);
struct regmap *regmap_init_ac97(struct snd_ac97 *ac97,
const struct regmap_config *config);
+struct regmap *regmap_init_ibt(struct hci_dev *hdev,
+ u16 opcode_read, u16 opcode_write,
+ const struct regmap_config *config);
struct regmap *devm_regmap_init(struct device *dev,
const struct regmap_bus *bus,
@@ -361,6 +365,9 @@ struct regmap *devm_regmap_init_mmio_clk(struct device
*dev, const char *clk_id,
const struct regmap_config *config);
struct regmap *devm_regmap_init_ac97(struct snd_ac97 *ac97,
const struct regmap_config *config);
+struct regmap *devm_regmap_init_ibt(struct hci_dev *hdev,
+ u16 opcode_read, u16 opcode_write,
+ const struct regmap_config *config);
bool regmap_ac97_default_volatile(struct device *dev, unsigned int reg);
--
1.9.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
