[PATCH v8] Add baudrate management for Bluetooth UART

[PATCH v8] Add baudrate management for Bluetooth UART

[Frederic Danis]

This patch set introduce baudrate management for Bluetooth UART
Controller setup and a first implementation for Broadcom BCM4324B3
used in Asus T100.

v7 -> v8:
- Patches 1 to 5 has been integrated
- Rename "struct hci_cp_bcm_set_speed" to "struct bcm_set_speed" and
  move it to btbcm.h
- Rename parameter "dummy" to "zero" in "struct bcm_set_speed"
- Add comments above vendor commands
- Add "BCM: " in BT_ERR strings
- Assign value of "param" variable above related vendor command

v6 -> v7:
- Fix setup when firmware is missing by moving
  request/release_firmware() out of btbcm_patchram().

v2 -> v6:
- Fixes for __hci_cmd_sync() has been integrated (patch v5)
- In btbcm_check_bdaddr(), merge controller address tests
- Fix declaration of speeds to use "unsigned int" type
- Rename default_speed to init_speed
- Rename operational_speed to oper_speed
- In case of error during vendor specific set_baudrate(), do not change
  host baudrate and continue without changing speed
- Discard changes to bcm_setup_patchram() and in btusb.c
- Introduce helper functions btbcm_initialize() and btbcm_finalize() to
  be used by the UART side of things.
Frederic Danis (1):
  Bluetooth: hci_uart: Add bcm_set_baudrate()

 drivers/bluetooth/btbcm.h   |  5 ++++
 drivers/bluetooth/hci_bcm.c | 58 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)

-- 
1.9.1

[PATCH v8] Bluetooth: hci_uart: Add bcm_set_baudrate()

[Frederic Danis]

Add vendor specific command to change controller device speed.

Signed-off-by: Frederic Danis <frederic.danis@linux.intel.com>
---
 drivers/bluetooth/btbcm.h   |  5 ++++
 drivers/bluetooth/hci_bcm.c | 58 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/drivers/bluetooth/btbcm.h b/drivers/bluetooth/btbcm.h
index f405f84..e1770d8 100644
--- a/drivers/bluetooth/btbcm.h
+++ b/drivers/bluetooth/btbcm.h
@@ -21,6 +21,11 @@
  *
  */
 
+struct bcm_set_speed {
+	__le16   zero;
+	__le32   speed;
+} __packed;
+
 #if IS_ENABLED(CONFIG_BT_BCM)
 
 int btbcm_check_bdaddr(struct hci_dev *hdev);
diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c
index 0704522..2a064a5 100644
--- a/drivers/bluetooth/hci_bcm.c
+++ b/drivers/bluetooth/hci_bcm.c
@@ -25,6 +25,7 @@
 #include <linux/errno.h>
 #include <linux/skbuff.h>
 #include <linux/firmware.h>
+#include <linux/tty.h>
 
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
@@ -32,11 +33,59 @@
 #include "btbcm.h"
 #include "hci_uart.h"
 
+#define BCM43XX_CLOCK_48 1
+#define BCM43XX_CLOCK_24 2
+
 struct bcm_data {
 	struct sk_buff *rx_skb;
 	struct sk_buff_head txq;
 };
 
+static int bcm_set_baudrate(struct hci_uart *hu, unsigned int speed)
+{
+	struct hci_dev *hdev = hu->hdev;
+	struct sk_buff *skb;
+	struct bcm_set_speed param;
+
+	if (speed > 3000000) {
+		u8 clock = BCM43XX_CLOCK_48;
+
+		BT_DBG("%s: Set Controller clock (%d)", hdev->name, clock);
+
+		/* This Broadcom specific command changes the UART's controller
+		 * clock for baud rate > 3000000.
+		 */
+		skb = __hci_cmd_sync(hdev, 0xfc45, 1, &clock, HCI_INIT_TIMEOUT);
+		if (IS_ERR(skb)) {
+			BT_ERR("%s: BCM: failed to write update clock command"
+			       " (%ld)", hdev->name, PTR_ERR(skb));
+			return PTR_ERR(skb);
+		}
+
+		kfree_skb(skb);
+	}
+
+	BT_DBG("%s: Set Controller UART speed to %d bit/s", hdev->name, speed);
+
+	param.zero = cpu_to_le16(0);
+	param.speed = cpu_to_le32(speed);
+
+	/* This Broadcom specific command changes the UART's controller baud
+	 * rate.
+	 */
+	skb = __hci_cmd_sync(hdev, 0xfc18, sizeof(param), &param,
+			     HCI_INIT_TIMEOUT);
+	if (IS_ERR(skb)) {
+		BT_ERR("%s: BCM: failed to write update baudrate command (%ld)",
+		       hdev->name, PTR_ERR(skb));
+		return PTR_ERR(skb);
+	}
+
+	kfree_skb(skb);
+
+	return 0;
+}
+
 static int bcm_open(struct hci_uart *hu)
 {
 	struct bcm_data *bcm;
@@ -107,6 +156,12 @@ static int bcm_setup(struct hci_uart *hu)
 	if (hu->proto->init_speed)
 		hci_uart_set_baudrate(hu, hu->proto->init_speed);
 
+	if (hu->proto->oper_speed) {
+		err = bcm_set_baudrate(hu, hu->proto->oper_speed);
+		if (!err)
+			hci_uart_set_baudrate(hu, hu->proto->oper_speed);
+	}
+
 finalize:
 	release_firmware(fw);
 
@@ -162,10 +217,13 @@ static struct sk_buff *bcm_dequeue(struct hci_uart *hu)
 static const struct hci_uart_proto bcm_proto = {
 	.id		= HCI_UART_BCM,
 	.name		= "BCM",
+	.init_speed	= 115200,
+	.oper_speed	= 4000000,
 	.open		= bcm_open,
 	.close		= bcm_close,
 	.flush		= bcm_flush,
 	.setup		= bcm_setup,
+	.set_baudrate	= bcm_set_baudrate,
 	.recv		= bcm_recv,
 	.enqueue	= bcm_enqueue,
 	.dequeue	= bcm_dequeue,
-- 
1.9.1

Re: [PATCH v8] Bluetooth: hci_uart: Add bcm_set_baudrate()

[Marcel Holtmann]

Hi Fred,

> Add vendor specific command to change controller device speed.
> 
> Signed-off-by: Frederic Danis <frederic.danis@linux.intel.com>
> ---
> drivers/bluetooth/btbcm.h   |  5 ++++
> drivers/bluetooth/hci_bcm.c | 58 +++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 63 insertions(+)
> 
> diff --git a/drivers/bluetooth/btbcm.h b/drivers/bluetooth/btbcm.h
> index f405f84..e1770d8 100644
> --- a/drivers/bluetooth/btbcm.h
> +++ b/drivers/bluetooth/btbcm.h
> @@ -21,6 +21,11 @@
>  *
>  */
> 
> +struct bcm_set_speed {
> +	__le16   zero;
> +	__le32   speed;
> +} __packed;
> +

I think this should actually be

	struct bcm_update_uart_baud_rate {
		__le16 zero;
		__le32 baud_rate;
	} __packed;

And lets just add this one as well

	struct bcm_write_uart_clock_setting {
		__u8 type;
	} __packed;

> #if IS_ENABLED(CONFIG_BT_BCM)
> 
> int btbcm_check_bdaddr(struct hci_dev *hdev);
> diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c
> index 0704522..2a064a5 100644
> --- a/drivers/bluetooth/hci_bcm.c
> +++ b/drivers/bluetooth/hci_bcm.c
> @@ -25,6 +25,7 @@
> #include <linux/errno.h>
> #include <linux/skbuff.h>
> #include <linux/firmware.h>
> +#include <linux/tty.h>
> 
> #include <net/bluetooth/bluetooth.h>
> #include <net/bluetooth/hci_core.h>
> @@ -32,11 +33,59 @@
> #include "btbcm.h"
> #include "hci_uart.h"
> 
> +#define BCM43XX_CLOCK_48 1
> +#define BCM43XX_CLOCK_24 2
> +

Lets put these in btbcm.h as well.

#define BCM_UART_CLOCK_48MHZ	0x01
#define BCM_UART_CLOCK_24MHZ	0x02

> struct bcm_data {
> 	struct sk_buff *rx_skb;
> 	struct sk_buff_head txq;
> };
> 
> +static int bcm_set_baudrate(struct hci_uart *hu, unsigned int speed)
> +{
> +	struct hci_dev *hdev = hu->hdev;
> +	struct sk_buff *skb;
> +	struct bcm_set_speed param;
> +
> +	if (speed > 3000000) {
> +		u8 clock = BCM43XX_CLOCK_48;
> +
> +		BT_DBG("%s: Set Controller clock (%d)", hdev->name, clock);
> +
> +		/* This Broadcom specific command changes the UART's controller
> +		 * clock for baud rate > 3000000.
> +		 */
> +		skb = __hci_cmd_sync(hdev, 0xfc45, 1, &clock, HCI_INIT_TIMEOUT);
> +		if (IS_ERR(skb)) {
> +			BT_ERR("%s: BCM: failed to write update clock command"
> +			       " (%ld)", hdev->name, PTR_ERR(skb));
> +			return PTR_ERR(skb);

In many cases we did this:

		int err = PTR_ERR(skb);
		BT_ERR("%s .. (%d)", hdev->name, err);
		return err;

I have the feeling that we might want to stick with this. Might be worth while to check how consistent we have actually been.

> +		}
> +
> +		kfree_skb(skb);
> +	}
> +
> +	BT_DBG("%s: Set Controller UART speed to %d bit/s", hdev->name, speed);
> +
> +	param.zero = cpu_to_le16(0);
> +	param.speed = cpu_to_le32(speed);
> +
> +	/* This Broadcom specific command changes the UART's controller baud
> +	 * rate.
> +	 */
> +	skb = __hci_cmd_sync(hdev, 0xfc18, sizeof(param), &param,
> +			     HCI_INIT_TIMEOUT);
> +	if (IS_ERR(skb)) {
> +		BT_ERR("%s: BCM: failed to write update baudrate command (%ld)",
> +		       hdev->name, PTR_ERR(skb));
> +		return PTR_ERR(skb);
> +	}
> +
> +	kfree_skb(skb);
> +
> +	return 0;
> +}
> +
> static int bcm_open(struct hci_uart *hu)
> {
> 	struct bcm_data *bcm;
> @@ -107,6 +156,12 @@ static int bcm_setup(struct hci_uart *hu)
> 	if (hu->proto->init_speed)
> 		hci_uart_set_baudrate(hu, hu->proto->init_speed);
> 
> +	if (hu->proto->oper_speed) {
> +		err = bcm_set_baudrate(hu, hu->proto->oper_speed);
> +		if (!err)
> +			hci_uart_set_baudrate(hu, hu->proto->oper_speed);
> +	}
> +
> finalize:
> 	release_firmware(fw);
> 
> @@ -162,10 +217,13 @@ static struct sk_buff *bcm_dequeue(struct hci_uart *hu)
> static const struct hci_uart_proto bcm_proto = {
> 	.id		= HCI_UART_BCM,
> 	.name		= "BCM",
> +	.init_speed	= 115200,
> +	.oper_speed	= 4000000,
> 	.open		= bcm_open,
> 	.close		= bcm_close,
> 	.flush		= bcm_flush,
> 	.setup		= bcm_setup,
> +	.set_baudrate	= bcm_set_baudrate,
> 	.recv		= bcm_recv,
> 	.enqueue	= bcm_enqueue,
> 	.dequeue	= bcm_dequeue,

Rest looks good.

Regards

Marcel