没有 Linux 的树莓派 4 上的蓝牙

Question

我正在研究非 Linux OS，现在正尝试在 Raspberry Pi 4.

上启用蓝牙

我有一些必要的驱动程序，例如：gpio、uart（pl011 和 mini-uart）、邮箱和通过该邮箱的 expgpio。

为了启用蓝牙，我做了一些步骤：

我按照 Linux 的 dts 中的描述配置 GPIO 以连接 UART0 到 BT/WiFi 筹码；
我通过邮箱设置BT_ONexpgpio为1（默认设置，确保即可）；

我向 UART0 写入了一些命令但没有任何反应 =( UART 驱动程序 return 成功并且读取命令答案总是超时。我想我可能会忘记初始化过程的一些步骤，但正如我在 Linux 日志中看到的那样，只有固件下载和许多命令，例如读取设备名称，可以在它之前执行。可能是我忘记启用某些时钟源或调节器，但我不知道从哪里开始研究。

Raspbian 内核日志的一部分包含额外的调试信息：

Jan 28 05:17:13 raspberrypi kernel: [   15.321055] Bluetooth: Core ver 2.22
Jan 28 05:17:13 raspberrypi kernel: [   15.321093] device class 'bluetooth': registering
Jan 28 05:17:13 raspberrypi kernel: [   15.321149] NET: Registered PF_BLUETOOTH protocol family
Jan 28 05:17:13 raspberrypi kernel: [   15.321158] Bluetooth: HCI device and connection manager initialized
Jan 28 05:17:13 raspberrypi kernel: [   15.321176] Bluetooth: HCI socket layer initialized
Jan 28 05:17:13 raspberrypi kernel: [   15.321189] Bluetooth: L2CAP socket layer initialized
Jan 28 05:17:13 raspberrypi kernel: [   15.321208] Bluetooth: SCO socket layer initialized
Jan 28 05:17:13 raspberrypi kernel: [   15.335356] Bluetooth: HCI UART driver ver 2.3
Jan 28 05:17:13 raspberrypi kernel: [   15.335377] Bluetooth: HCI UART protocol H4 registered at id 0
Jan 28 05:17:13 raspberrypi kernel: [   15.335387] bus: 'serial': add driver hci_uart_h5
Jan 28 05:17:13 raspberrypi kernel: [   15.335456] Bluetooth: HCI UART protocol Three-wire (H5) registered at id 2
Jan 28 05:17:13 raspberrypi kernel: [   15.335480] bus: 'platform': add driver hci_bcm
Jan 28 05:17:13 raspberrypi kernel: [   15.335641] bus: 'serial': add driver hci_uart_bcm
Jan 28 05:17:13 raspberrypi kernel: [   15.335679] Bluetooth: HCI UART protocol Broadcom registered at id 7
Jan 28 05:17:13 raspberrypi kernel: [   15.337922] Bluetooth: TTY name ttyAMA0
Jan 28 05:17:13 raspberrypi kernel: [   15.338543] Bluetooth: hci_uart_register_dev
Jan 28 05:17:13 raspberrypi kernel: [   15.338599] device: 'hci0': device_add
Jan 28 05:17:13 raspberrypi kernel: [   15.345358] device: 'rfkill1': device_add
Jan 28 05:17:13 raspberrypi kernel: [   15.345497] Bluetooth: HCI UART protocol set. Proto H4; id 0
Jan 28 05:17:13 raspberrypi kernel: [   15.345530] Bluetooth: hci_uart_open hci0 5d898f04
Jan 28 05:17:13 raspberrypi kernel: [   15.345543] Bluetooth: hci_uart_setup: START
Jan 28 05:17:13 raspberrypi kernel: [   15.345550] Bluetooth: hci_uart_setup: init speed = 0
Jan 28 05:17:13 raspberrypi kernel: [   15.345557] Bluetooth: hci_uart_setup: oper speed = 0
Jan 28 05:17:13 raspberrypi kernel: [   15.352975] Bluetooth: hci0: type 1 len 3
Jan 28 05:17:13 raspberrypi kernel: [   15.353010] Bluetooth skb:   00000000: 01 03 10 00
Jan 28 05:17:13 raspberrypi kernel: [   15.353026] Bluetooth: hci_uart_write_work written 4
Jan 28 05:17:13 raspberrypi kernel: [   15.353760] Bluetooth: hci0: type 1 len 3
Jan 28 05:17:13 raspberrypi kernel: [   15.353826] Bluetooth skb:   00000000: 01 01 10 00
....
a lot of lines
....
Jan 28 05:17:13 raspberrypi btuart[479]: bcm43xx_init
Jan 28 05:17:13 raspberrypi btuart[479]: Flash firmware /lib/firmware/brcm/BCM4345C0.hcd
Jan 28 05:17:13 raspberrypi btuart[479]: Set Controller UART speed to 3000000 bit/s
Jan 28 05:17:13 raspberrypi btuart[479]: Device setup complete
Jan 28 05:17:13 raspberrypi systemd[1]: Starting Load/Save RF Kill Switch Status...
Jan 28 05:17:13 raspberrypi systemd[1]: Started Configure Bluetooth Modems connected by UART.
Jan 28 05:17:13 raspberrypi systemd[1]: Reached target Multi-User System.
Jan 28 05:17:13 raspberrypi systemd[1]: Reached target Graphical Interface.
Jan 28 05:17:13 raspberrypi systemd[1]: Starting Update UTMP about System Runlevel Changes...
Jan 28 05:17:13 raspberrypi systemd[625]: Reached target Bluetooth.
Jan 28 05:17:13 raspberrypi systemd[1]: Started Load/Save RF Kill Switch Status.
Jan 28 05:17:13 raspberrypi systemd[1]: Created slice system-bthelper.slice.
Jan 28 05:17:13 raspberrypi systemd[1]: Starting Raspberry Pi bluetooth helper...
Jan 28 05:17:13 raspberrypi systemd[1]: systemd-update-utmp-runlevel.service: Succeeded.
Jan 28 05:17:13 raspberrypi systemd[1]: Finished Update UTMP about System Runlevel Changes.
Jan 28 05:17:13 raspberrypi bthelper[774]: Raspberry Pi BDADDR already set
Jan 28 05:17:13 raspberrypi systemd[1]: Finished Raspberry Pi bluetooth helper.
Jan 28 05:17:13 raspberrypi kernel: [   15.490868] Bluetooth: hci0: type 1 len 8
Jan 28 05:17:13 raspberrypi kernel: [   15.490909] Bluetooth skb:   00000000: 01 1c fc 05 01 02 00 01 01
Jan 28 05:17:13 raspberrypi kernel: [   15.490930] Bluetooth: hci_uart_write_work written 9

提前致谢

Answer 1

对于 H4 协议，必须使用具有硬件流控制的 UART。将 HFC 支持添加到 PL011 UART 驱动程序可解决问题。

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