Linux: 4.14.x: CONFIG_BT_HCIUART_BCM is not enabled in arch/arm/configs/bcmrpi_defconfig

Created on 29 Mar 2018 · 18Comments · Source: raspberrypi/linux

I have a RPi Zero W running Void Linux (4.14.30 armv6l), which uses the default config arch/arm/configs/bcmrpi_defconfig.

I haven't been able to get Bluetooth working. When running btattach (hciattach is deprecated and unavailable on Void Linux), I get the following:

# btattach -B /dev/ttyAMA0 -P bcm -S 3000000
Attaching Primary controller to /dev/ttyAMA0
Switched line discipline from 0 to 15
Failed to set protocol: Protocol not supported
No controller attached

When comparing dmesg output with Raspbian (4.9.80), I noticed that on Void Linux the Broadcom UART protocol wasn't being registered. While on Raspbian dmesg shows the following:

...
Bluetooth: HCI UART protocol Broadcom registered
...

This has led me to suspect that Broadcom UART protocol support was missing from the kernel.

Inspecting the 4.14.x config arch/arm/configs/bcmrpi_defconfig shows that CONFIG_BT_HCIUART_BCM is not enabled, but is in 4.9.x. I believe this is caused by this commit introduced in 4.14, which added a CONFIG_BT_HCIUART_SERDEV dependency to CONFIG_BT_HCIUART_BCM. CONFIG_BT_HCIUART_SERDEV needs CONFIG_SERIAL_DEV_BUS, which is also not enabled. Without these new dependencies, the hci_uart module is not built with Broadcom UART protocol support.

Source

amak79

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Most helpful comment

I was able to get btattach to work on Raspbian after disabling the hciuart service, and using the h4 protocol instead of bcm:

# btattach -B /dev/ttyAMA0 -P h4
Attaching Primary controller to /dev/ttyAMA0
Switched line discipline from 0 to 15
Device index 0 attached

Using the -S option with 3000000, 924600 or 460800 prevents the controller from working, so I dropped it. The controller MAC address is set to AA:AA:AA:AA:AA:AA instead of the serial number derived one. I'm not sure what effect that has. I confirmed it works by paring a game controller and testing it with jstest.

Although btattach now works with Void Linux and the hci0 device is visible under /sys/class/bluetooth, Bluetooth still doesn't work. For some reason bluetoothctl doesn't list any controllers. I have the BCM43430A1.hcd firmware file placed in /lib/firmware/brcm, but btattach doesn't appear to load it, even on Raspbian.

amak79 on 31 Mar 2018

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After upgrading Raspbian to 4.14.x which doesn't have CONFIG_BT_HCIUART_BCM enabled, it appears that Bluetooth works without it. I can only assume that the issue on Void Linux lies with btattach. All other distros are using a patched hciattach. Is it even possible to use plain btattach?

amak79 on 31 Mar 2018

I was able to get btattach to work on Raspbian after disabling the hciuart service, and using the h4 protocol instead of bcm:

# btattach -B /dev/ttyAMA0 -P h4
Attaching Primary controller to /dev/ttyAMA0
Switched line discipline from 0 to 15
Device index 0 attached

amak79 on 31 Mar 2018

🎉1 👍1

I finally got Bluetooth working on Void Linux using btattach. I'm not sure what it was, maybe the Bluetooth service or RPi needed a restart. I can pair the game controller, even without the BCM43430A1.hcd firmware file:

# dmesg
...
[ 1279.244366] hid-generic 0005:2DC8:3820.0003: unknown main item tag 0x0
[ 1279.246446] input: 8Bitdo NES30 Pro as /devices/platform/soc/20201000.serial/tty/ttyAMA0/hci0/hci0:11/0005:2DC8:3820.0003/input/input2
[ 1279.254289] hid-generic 0005:2DC8:3820.0003: input,hidraw0: BLUETOOTH HID v1.00 Gamepad [8Bitdo NES30 Pro] on aa:aa:aa:aa:aa:aa
...

The AA:AA:AA:AA:AA:AA MAC address issue remains. btattach doesn't offer a way to set the MAC address like hciattatch does. Is there any other way to set the controller MAC address?

Is the use of the HCI UART H4 protocol correct? I assumed the BCM protocol would be the correct one, but CONFIG_BT_HCIUART_BCM is not enabled in the 4.14 kernel and Bluetooth still works.

amak79 on 1 Apr 2018

I reverted to Raspbian 4.9.x which has CONFIG_BT_HCIUART_BCM enabled. I ran btattach with -P bcm when I noticed the BCM protocol was attempting to load the brcm/BCM.hcd firmware. I then copied BCM43430A1.hcd to BCM.hcd and ran btattach again with the following results:

# dmesg
...
[  110.648332] uart-pl011 20201000.serial: no DMA platform data
[  110.699913] Bluetooth: HCI UART driver ver 2.3
[  110.699938] Bluetooth: HCI UART protocol H4 registered
[  110.699944] Bluetooth: HCI UART protocol Three-wire (H5) registered
[  110.700199] Bluetooth: HCI UART protocol Broadcom registered
[  110.726961] Bluetooth: hci0: BCM: failed to write clock (-56)
[  110.734896] Bluetooth: hci0: BCM: chip id 94
[  110.734920] Bluetooth: hci0: BCM (001.002.009) build 0000
[  111.317099] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[  111.317113] Bluetooth: BNEP filters: protocol multicast
[  111.317136] Bluetooth: BNEP socket layer initialized
[  114.416341] Bluetooth: hci0: BCM: failed to write clock (-56)
[  114.422338] Bluetooth: hci0: BCM (001.002.009) build 0360

I appears that the firmware is loaded (build changes from 0000 to 0360), but an error occurs. The hci0 device is visible under /sys/class/bluetooth, but no controller is available in bluetoothctl. Does the BCM protocol require a different firmware file, or is there an issue with BCM43430A1.hcd?

I'm fairly certain that my original conclusion was correct. The CONFIG_BT_HCIUART_BCM option should be enabled. It would be great to have someone from the RPi kernel team state their opinion on this issue.

amak79 on 4 Apr 2018

As you have said, Raspbian is happy without CONFIG_BT_HCIUART_BCM. If you think that some other operating modes require it, build your own kernel with the option enabled, verify that it solves the problem, then report back.

pelwell on 4 Apr 2018

Thank you for the reply.

As I already mentioned, Void Linux uses the same kernel config as Raspbian. Building my own kernel wouldn't help. I can use Raspbian with kernel 4.9 while trying to solve this issue. The lack of CONFIG_BT_HCIUART_BCM affects distributions that only have btattach available, instead of the deprecated hciattach that Raspbian uses.

There is also the additional issue that I mentioned in my previous post, where the firmware is loaded, but no controller is available when using btattach.

amak79 on 4 Apr 2018

As I already mentioned, Void Linux uses the same kernel config as Raspbian. Building my own kernel wouldn't help.

It would help because you would enable CONFIG_BT_HCIUART_BCM before building the kernel (as I said - "build your own kernel _with the option enabled_"). This would then allow you to confirm that it makes a positive difference.

We don't have the resources to support all the different versions of Linux out there - if there are changes we can make to the standards kernels to better support them then we will consider doing so, but others will have to diagnosis. The Void Linux maintainers (and other users) may be able to help you.

pelwell on 4 Apr 2018

I built my own kernel with the these additional options added to the default arch/arm/configs/bcmrpi_defconfig:

CONFIG_SERIAL_DEV_BUS=m
CONFIG_BT_HCIUART_SERDEV=y
CONFIG_BT_HCIUART_BCM=y

Running btattach:

btattach -B /dev/ttyAMA0 -P bcm -S 3000000
Attaching Primary controller to /dev/ttyAMA0
Switched line discipline from 0 to 15
Device index 0 attached

dmesg output:

...
[    8.058194] Bluetooth: Core ver 2.22
[    8.058367] NET: Registered protocol family 31
[    8.058376] Bluetooth: HCI device and connection manager initialized
[    8.060419] Bluetooth: HCI socket layer initialized
[    8.060446] Bluetooth: L2CAP socket layer initialized
[    8.060539] Bluetooth: SCO socket layer initialized
[    8.226164] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[    8.226182] Bluetooth: BNEP filters: protocol multicast
[    8.226215] Bluetooth: BNEP socket layer initialized
[   24.342851] uart-pl011 20201000.serial: no DMA platform data
[   24.408126] Bluetooth: HCI UART driver ver 2.3
[   24.408143] Bluetooth: HCI UART protocol H4 registered
[   24.408150] Bluetooth: HCI UART protocol Three-wire (H5) registered
[   24.408575] Bluetooth: HCI UART protocol Broadcom registered
[   24.542235] Bluetooth: hci0: BCM: chip id 94
[   24.544510] Bluetooth: hci0: BCM: features 0x2e
[   24.567958] Bluetooth: hci0: BCM43430A1
[   24.567990] Bluetooth: hci0: BCM43430A1 (001.002.009) build 0000
[   28.349397] Bluetooth: hci0: BCM (001.002.009) build 0360
[  238.722183] Bluetooth: HIDP (Human Interface Emulation) ver 1.2
[  238.722228] Bluetooth: HIDP socket layer initialized
[  240.884171] hid-generic 0005:2DC8:3820.0001: unknown main item tag 0x0
[  240.886488] input: 8Bitdo NES30 Pro as /devices/platform/soc/20201000.serial/tty/ttyAMA0/hci0/hci0:12/0005:2DC8:3820.0001/input/input0
[  240.893146] hid-generic 0005:2DC8:3820.0001: input,hidraw0: BLUETOOTH HID v1.00 Gamepad [8Bitdo NES30 Pro] on b8:27:eb:f0:c9:98

I can report that Bluetooth works. I was able to pair my game controller. The correct firmware was loaded without error, and a proper MAC address assigned to the hci0 device i.e. not AA:AA:AA:AA:AA:AA. I can also set the baud rate, which previously prevented the controller from working.

amak79 on 4 Apr 2018

👍1

Excellent - thank you. I'll make sure we enable the option in future builds.

pelwell on 4 Apr 2018

Thank you.

Is there a public repository where the Bluetooth firmware files BCM43430A1.hcd and BCM4345C0.hcd are kept? I couldn't find one, so I grabbed the files from a Raspbian installation. Having a public repository would make it possible to have the files available via the Void Linux rpi-firmware package.

amak79 on 5 Apr 2018

@amak79 Just added a repo you could grab them from directly: https://github.com/RPi-Distro/bluez-firmware/tree/master/broadcom

XECDesign on 5 Apr 2018

Thank you.

amak79 on 5 Apr 2018

Enabling those two settings (only CONFIG_SERIAL_DEV_BUS=m and CONFIG_BT_HCIUART_BCM=y are required - CONFIG_BT_HCIUART_SERDEV=y is implied) causes serdev.ko to be built (an 18kB module) and hci_uart.ko to increase in size by another 18kB - the static kernel is unchanged. I think this is acceptable, especially since CONFIG_BT_HCIUART_BCM=y was present in 4.9.

The defconfigs have now been updated accordingly.

pelwell on 5 Apr 2018

@pelwell I think you may have overlooked CONFIG_SERIAL_DEV_BUS=m in arch/arm64/configs/bcmrpi3_defconfig. It's still not enabled.

amak79 on 5 Apr 2018

It's an omission rather than an oversight - we don't support 64-bit builds and therefore don't compile or test them, so we generally leave the defconfig alone unless prompted, but now you've mentioned it I can add it.

pelwell on 5 Apr 2018

I believe this issue can now be closed?

JamesH65 on 20 Apr 2018

Yes.

amak79 on 21 Apr 2018

CONFIG_BT_HCIUART_BCM
@amak79
I am using rpi-4.19.y(4.19.108) for AArch64.
Are you sure you can add "CONFIG_BT_HCIUART_BCM" to the default config before building the kernel? I add "CONFIG_BT_HCIUART_BCM=y", but it disappeared after building kernel. So it didn't work. When I btattached /dev/ttyAMA0 with bcm, I got these：
# btattach -B /dev/ttyAMA0 -P bcm -S 3000000
Attaching Primary controller to /dev/ttyAMA0
Switched line discipline from 0 to 15
Failed to set protocol: Protocol not supported

Can you tell me how you solved this? Thanks.