[yocto] meta-raspberrypi systemd rpi0-w bluetooth startup

[Dengke Du]

Raspberry pi have two built-in UARTs, PL011 and mini UART

by default: /dev/ttyS0 refers to the mini UART, /dev/ttyAMA0 refers to 
the PL011

https://www.raspberrypi.org/documentation/configuration/uart.md

So I think the brcm43438 service should use the /dev/ttyAMA0.


On 2018年03月20日 10:41, Dengke Du wrote:
>
> For rpi0-w bluetooth, before the commit:
>
> https://github.com/agherzan/meta-raspberrypi/commit/6235b0a8543bcf6704d0fe0156ab2b847a4ea0bc#diff-70e4910388c3702c52118d7acf7556e7
>
> the brcm43438.service always failed, because it depends on 
> /dev/ttyAMA0,after that commit, the 'udev-rules-rpi' added to the 
> RDEPENDS for rpi0-w,we
>
> can check it here:
>
> https://github.com/agherzan/meta-raspberrypi/commit/6235b0a8543bcf6704d0fe0156ab2b847a4ea0bc#diff-3b2568c620828b0ba653c1070041318aR52
>
> for service brcm43438, but I still use the /dev/ttyAMA0 in it, not 
> /dev/serial1(when I use /dev/serial1, the service failed), the service 
> can start everytime correctly.
>
>
> On 2018年03月19日 02:10, r10kindsofpeople wrote:
>> Update:  I suspect this is not the proper way to do this, but in case 
>> it provides useful information toward a better solution...
>> 1) systemctl disable brcm43438.service
>> 2) modified 99-com.rules to include TAG+="systemd" and 
>> ENV{SYSTEMD_WANTS}="device-brcm43438.service"
>> 3) cp /lib/systemd/system/brcm43438.service 
>> /etc/systemd/system/device-brcm43438.service
>> 4) modified device-brcm43438.service to be as follows:
>> [Unit]
>> Description=Broadcom BCM43438 bluetooth HCI
>>
>> [Service]
>> Type=simple
>> ExecStart=/usr/bin/hciattach -n /dev/serial1 bcm43xx 921600 noflow -
>> Restart=on-failure
>>
>> note removal of Before, After, ConditionPath, Install sections and 
>> addition of Restart=on-failure.  This last was to cope with an 
>> intermittent timeout in hciattach.  Suppose I should have tried 
>> increasing the timeout first.
>>
>> This seems to have gotten me to the point of it starting up at least 
>> 10 times successfully.  Bottom line, in my opinion, is that 
>> brcm43438.service is somehow running  before the udev script can 
>> create the symbolic link for /dev/serial1 -> /dev/ttyAMA0 despite the 
>> "After=dev-serial1.device" clause.
>>
>> John
>>
>>
>> On Sat, Mar 17, 2018 at 12:32 PM r10kindsofpeople 
>> <r10kindsofpeople at gmail.com <mailto:r10kindsofpeople at gmail.com>> wrote:
>>
>>     Background:  I'm trying to bring up the pi zero w's bluetooth
>>     using systemd.  Started with rocko and then moved to 'master' of
>>     meta-raspberry pi, sync'd about a week ago after noticing that
>>     there were some recent updates in this area.
>>
>>     There was an initial problem with /dev/serial1 not showing up...I
>>     found udev-rules-rpi.bb <http://udev-rules-rpi.bb>, added it to
>>     my layer, and when it still didn't show up in my rootfs, I punted
>>     and installed it in /etc/udev/rules.d by hand and now
>>     /dev/serial1 shows up.  Given time, I can probably fix the recipe
>>     on my own, so moving on.
>>
>>     But brcm43438.service still fails on boot.  Despite having
>>     "After=dev-serial1.device" in the service Unit section, it fails
>>     with:
>>
>>     Mar 17 16:21:13 raspberrypi0-wifi systemd[1]: Started Broadcom
>>     BCM43438 bluetooth HCI.
>>     Mar 17 16:21:14 raspberrypi0-wifi hciattach[105]: Can't open
>>     serial port: No such file or directory
>>     Mar 17 16:21:14 raspberrypi0-wifi hciattach[105]: Can't
>>     initialize device: No such file or directory
>>     Mar 17 16:21:14 raspberrypi0-wifi systemd[1]:
>>     [[0;1;39mbrcm43438.service: Main process exited, code=exited,
>>     status=1/FAILURE[[0m
>>     Mar 17 16:21:14 raspberrypi0-wifi systemd[1]:
>>     [[0;1;39mbrcm43438.service: Unit entered failed state.[[0m
>>     Mar 17 16:21:14 raspberrypi0-wifi systemd[1]:
>>     [[0;1;39mbrcm43438.service: Failed with result 'exit-code'.[[0m
>>
>>     If, after booting and ssh'ing into pi, I restart the service, it
>>     starts successfully.
>>
>>     Any hints about what I might change to get the brcm43438.service
>>     to start correctly the first time (every time)?
>>
>>     John
>>
>>
>>
>
>
>

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