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>
diff --git a/drivers/bluetooth/btintel.c b/drivers/bluetooth/btintel.c
index 9e18988..7047fe6 100644
--- a/drivers/bluetooth/btintel.c
+++ b/drivers/bluetooth/btintel.c
@@ -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 @@
}
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, ®map_ibt, ctx, ®map_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);