Hi Martin,
> Realtek RTL8723BS and RTL8723DS are SDIO wifi chips with an embedded
> Bluetooth controller which connects to the host via UART.
> The H5 protocol is used for communication between host and device.
>
> The Realtek "rtl8723bs_bt" and "rtl8723ds_bt" userspace Bluetooth UART
> initialization tools (rtk_hciattach) use the following sequence:
> 1) send H5 sync pattern (already supported by hci_h5)
> 2) get LMP version (already supported by btrtl)
> 3) get ROM version (already supported by btrtl)
> 4) load the firmware and config for the current chipset (already
> supported by btrtl)
> 5) read UART settings from the config blob (already supported by btrtl)
> 6) send UART settings via a vendor command to the device (which changes
> the baudrate of the device and enables or disables flow control
> depending on the config)
> 7) change the baudrate and flow control settings on the host
> 8) send the firmware and config blob to the device (already supported by
> btrtl)
>
> This uses the serdev library as well as the existing btrtl driver to
> initialize the Bluetooth functionality, which consists of:
> - identifying the device and loading the corresponding firmware and
> config blobs (steps #2, #3 and #4)
> - configuring the baudrate and flow control (steps #6 and #7)
> - uploading the firmware to the device (step #8)
>
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
> ---
> drivers/bluetooth/Kconfig | 1 +
> drivers/bluetooth/hci_h5.c | 205 +++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 206 insertions(+)
>
> diff --git a/drivers/bluetooth/Kconfig b/drivers/bluetooth/Kconfig
> index 60e1c7d6986d..3001f1200c72 100644
> --- a/drivers/bluetooth/Kconfig
> +++ b/drivers/bluetooth/Kconfig
> @@ -146,6 +146,7 @@ config BT_HCIUART_LL
> config BT_HCIUART_3WIRE
> bool "Three-wire UART (H5) protocol support"
> depends on BT_HCIUART
> + select BT_RTL if SERIAL_DEV_BUS
> help
> The HCI Three-wire UART Transport Layer makes it possible to
> user the Bluetooth HCI over a serial port interface. The HCI
while this is fine initially, I think long term this is not sustainable. So we need to abstract the H:5 part and the vendor specific setup part so that you can have a hci_rtl.c that uses H:5 instead of H:4 and still is as tiny and simple as our H:4 drivers.
One other think I am not really happy about here is the Kconfig entry itself. You need to know that you need 3WIRE and SERDEV to magically enable RTL UART support. Maybe it would be better to just have a CONFIG_HCIUART_RTL and duplicate the config entry just specific to RTL. It then can select RTL, but in the Makefile it will result in using the same hci_h5.c file.
> diff --git a/drivers/bluetooth/hci_h5.c b/drivers/bluetooth/hci_h5.c
> index 6cfc2f276250..a03acc3b1b52 100644
> --- a/drivers/bluetooth/hci_h5.c
> +++ b/drivers/bluetooth/hci_h5.c
> @@ -28,7 +28,14 @@
> #include <net/bluetooth/bluetooth.h>
> #include <net/bluetooth/hci_core.h>
>
> +#include <linux/gpio/consumer.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/serdev.h>
> +
> #include "hci_uart.h"
> +#include "btrtl.h"
>
> #define HCI_3WIRE_ACK_PKT 0
> #define HCI_3WIRE_LINK_PKT 15
> @@ -97,6 +104,13 @@ struct h5 {
> } sleep;
> };
>
> +struct h5_device {
> + struct hci_uart hu;
> + struct gpio_desc *enable_gpio;
> + struct gpio_desc *reset_gpio;
> + int (*vendor_setup)(struct h5_device *h5_dev);
> +};
> +
> static void h5_reset_rx(struct h5 *h5);
>
> static void h5_link_control(struct hci_uart *hu, const void *data, size_t len)
> @@ -190,6 +204,7 @@ static int h5_open(struct hci_uart *hu)
> {
> struct h5 *h5;
> const unsigned char sync[] = { 0x01, 0x7e };
> + int err;
>
> BT_DBG("hu %p", hu);
>
> @@ -210,6 +225,14 @@ static int h5_open(struct hci_uart *hu)
>
> h5->tx_win = H5_TX_WIN_MAX;
>
> + if (hu->serdev) {
> + err = serdev_device_open(hu->serdev);
> + if (err) {
> + bt_dev_err(hu->hdev, "failed to open serdev: %d", err);
> + return err;
> + }
> + }
> +
> /* Send initial sync request */
> h5_link_control(hu, sync, sizeof(sync));
> mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
> @@ -217,6 +240,25 @@ static int h5_open(struct hci_uart *hu)
> return 0;
> }
>
> +static int h5_setup(struct hci_uart *hu)
> +{
> + int err;
> + struct h5_device *h5_dev;
> +
> + if (!hu->serdev)
> + return 0;
> +
> + h5_dev = serdev_device_get_drvdata(hu->serdev);
> +
> + if (h5_dev->vendor_setup) {
> + err = h5_dev->vendor_setup(h5_dev);
> + if (err)
> + return err;
> + }
> +
> + return 0;
> +}
> +
> static int h5_close(struct hci_uart *hu)
> {
> struct h5 *h5 = hu->priv;
> @@ -227,6 +269,15 @@ static int h5_close(struct hci_uart *hu)
> skb_queue_purge(&h5->rel);
> skb_queue_purge(&h5->unrel);
>
> + if (hu->serdev) {
> + struct h5_device *h5_dev;
> +
> + h5_dev = serdev_device_get_drvdata(hu->serdev);
> + gpiod_set_value_cansleep(h5_dev->enable_gpio, 0);
> +
> + serdev_device_close(hu->serdev);
> + }
> +
> kfree(h5);
>
> return 0;
> @@ -736,10 +787,160 @@ static int h5_flush(struct hci_uart *hu)
> return 0;
> }
>
> +#if IS_ENABLED(CONFIG_SERIAL_DEV_BUS)
> +static int h5_setup_realtek(struct h5_device *h5_dev)
> +{
> + struct hci_uart *hu = &h5_dev->hu;
> + int err = 0, retry = 3;
> + struct sk_buff *skb;
> + struct btrtl_device_info *btrtl_dev;
> + __le32 baudrate_data;
> + u32 device_baudrate;
> + unsigned int controller_baudrate;
> + bool flow_control;
> +
> + /* devices always start with flow control disabled and even parity */
> + serdev_device_set_flow_control(hu->serdev, false);
> + serdev_device_set_parity(hu->serdev, true, false);
> +
> + do {
> + /* disable the device and put it into reset. some devices only
> + * have one of these lines, so we toggle both here to support
> + * all combinations.
> + */
> + gpiod_set_value_cansleep(h5_dev->reset_gpio, 1);
> + gpiod_set_value_cansleep(h5_dev->enable_gpio, 0);
> +
> + /* wait until the device is disabled and/or reset. 500ms are
> + * chosen by manually testing on a RTL8723BS. shorter wait
> + * times lead to a non-responding device.
> + */
> + msleep(500);
> +
> + /* take the device out of reset and enable it. */
> + gpiod_set_value_cansleep(h5_dev->reset_gpio, 0);
> + gpiod_set_value_cansleep(h5_dev->enable_gpio, 1);
> +
> + /* after that we need to wait 500ms, otherwise the device might
> + * not respond in all cases. this was determined by testing
> + * with a RTL8723BS.
> + */
> + msleep(500);
> +
> + btrtl_dev = btrtl_initialize(hu->hdev);
> + if (!IS_ERR(btrtl_dev))
> + break;
> +
> + /* Toggle the enable and reset pins above and try again */
> + } while (retry--);
> +
> + if (IS_ERR(btrtl_dev))
> + return PTR_ERR(btrtl_dev);
> +
> + err = btrtl_get_uart_settings(hu->hdev, btrtl_dev,
> + &controller_baudrate, &device_baudrate,
> + &flow_control);
> + if (err)
> + goto out_free;
> +
> + baudrate_data = cpu_to_le32(device_baudrate);
> + skb = __hci_cmd_sync(hu->hdev, 0xfc17, sizeof(baudrate_data),
> + &baudrate_data, HCI_INIT_TIMEOUT);
> + if (IS_ERR(skb)) {
> + bt_dev_err(hu->hdev, "set baud rate command failed");
> + err = -PTR_ERR(skb);
> + goto out_free;
> + } else {
> + kfree_skb(skb);
> + }
> +
> + serdev_device_set_baudrate(hu->serdev, controller_baudrate);
> + serdev_device_set_flow_control(hu->serdev, flow_control);
> +
> + err = btrtl_download_firmware(hu->hdev, btrtl_dev);
> +
> +out_free:
> + btrtl_free(btrtl_dev);
> +
> + return err;
> +}
> +
> +static const struct hci_uart_proto h5p;
> +
> +static int hci_h5_probe(struct serdev_device *serdev)
> +{
> + struct hci_uart *hu;
> + struct h5_device *h5_dev;
> +
> + h5_dev = devm_kzalloc(&serdev->dev, sizeof(*h5_dev), GFP_KERNEL);
> + if (!h5_dev)
> + return -ENOMEM;
> +
> + hu = &h5_dev->hu;
> + hu->serdev = serdev;
> +
> + serdev_device_set_drvdata(serdev, h5_dev);
> +
> + h5_dev->vendor_setup = of_device_get_match_data(&serdev->dev);
> +
> + h5_dev->enable_gpio = devm_gpiod_get_optional(&serdev->dev, "enable",
> + GPIOD_OUT_HIGH);
Indentation mistake.
> + if (IS_ERR(h5_dev->enable_gpio))
> + return PTR_ERR(h5_dev->enable_gpio);
> +
> + h5_dev->reset_gpio = devm_gpiod_get_optional(&serdev->dev, "reset",
> + GPIOD_OUT_LOW);
> + if (IS_ERR(h5_dev->reset_gpio))
> + return PTR_ERR(h5_dev->reset_gpio);
> +
> + hci_uart_set_speeds(hu, 115200, 0);
> +
> + return hci_uart_register_device(hu, &h5p);
> +}
> +
> +static void hci_h5_remove(struct serdev_device *serdev)
> +{
> + struct h5_device *h5_dev = serdev_device_get_drvdata(serdev);
> + struct hci_uart *hu = &h5_dev->hu;
> + struct hci_dev *hdev = hu->hdev;
> +
> + cancel_work_sync(&hu->write_work);
> +
> + hci_unregister_dev(hdev);
> + hci_free_dev(hdev);
> + hu->proto->close(hu);
> +}
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id hci_h5_of_match[] = {
> + {
> + .compatible = "realtek,rtl8723bs-bluetooth",
> + .data = h5_setup_realtek
> + },
> + {
> + .compatible = "realtek,rtl8723ds-bluetooth",
> + .data = h5_setup_realtek
> + },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, hci_h5_of_match);
> +#endif
> +
> +static struct serdev_device_driver hci_h5_drv = {
> + .driver = {
> + .name = "hci-h5",
> + .of_match_table = of_match_ptr(hci_h5_of_match),
> + },
> + .probe = hci_h5_probe,
> + .remove = hci_h5_remove,
> +};
> +#endif
> +
> static const struct hci_uart_proto h5p = {
> .id = HCI_UART_3WIRE,
> .name = "Three-wire (H5)",
> .open = h5_open,
> + .setup = h5_setup,
> .close = h5_close,
> .recv = h5_recv,
> .enqueue = h5_enqueue,
> @@ -749,10 +950,14 @@ static const struct hci_uart_proto h5p = {
>
> int __init h5_init(void)
> {
> + serdev_device_driver_register(&hci_h5_drv);
> +
> return hci_uart_register_proto(&h5p);
> }
>
> int __exit h5_deinit(void)
> {
> + serdev_device_driver_unregister(&hci_h5_drv);
> +
> return hci_uart_unregister_proto(&h5p);
> }
Regards
Marcel
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