Hello Robert,
On 10/9/20 2:30 PM, Robert Carnecky (Neopsis) wrote:
>> Try adding to arch/arm/dts/bcm2837-rpi-cm3.dts:
>>
>> &uart1 {
>> pinctrl-names = "default";
>> pinctrl-0 = <&uart1_gpio14>;
>> status = "okay";
>> };
>
> I extended arch/arm/dts/bcm2837-rpi-cm3.dts as advised +
> additionally I set UART0 to pins 32/33.
>
> &uart0 {
> pinctrl-names = "default";
> pinctrl-0 = <&uart0_gpio32>;
> status = "okay";
> };
>
> I still cannot see Barebox console on boot, however, the Barebox loader
> starts in 3 seconds my kernel and I get the Linux console output on
> UART1/ttyS0.
Strange that this made the kernel boot now. Maybe somewhere an unclocked
peripheral was being accessed before?
> Now my Linux boots as expected, unfortunately without
> visible Barebox console. I tried all Barebox console setting
> (NONE/ALL/FIRST), same result, no Barebox console output on UART0
> or UART1.
Huh, you did listen at the UART0 _before_ the RS-485 transceiver?
UART0 should work, at least it apparently did when the CM3 support
was added.
>> If that doesn't help, use CONSOLE_ACTIVATE_ALL and listen
>> on UART0 before the RS-485 transceiver and paste the
>> dmesg and devinfo input you get.
>
> # dmesg | grep tty
> [ 0.000000] Kernel command line: console=ttyS0,115200
> coherent_pool=1M snd_bcm2835.enable_compat_alsa=0
> snd_bcm2835.enable_hdmi=1 snd_bcm2835.enable_headphones=1
> 8250.nr_uarts=1 bcm2708_fb.fbwidth=656
> bcm2708_fb.fbheight=416 bcm2708_fb.fbswap=1
> smsc95xx.macaddr=B8:27:EB:C5:7D:E3 vc_mem.mem_base=0x3ec00000
> vc_mem.mem_size=0x40000000 root=/dev/mmcblk0p2 console=ttyS0,115200
> rootfstype=ext4 elevator=deadline rootwait
> [ 1.289058] printk: console [ttyS0] disabled
> [ 1.289175] 3f215040.serial: ttyS0 at MMIO 0x0 (irq = 53, base_baud
> = 50000000) is a 16550
> [ 1.945483] printk: console [ttyS0] enabled
> [ 2.432604] 3f201000.serial: ttyAMA0 at MMIO 0x3f201000 (irq = 81,
> base_baud = 0) is a PL011 rev2
>
> # stty -F /dev/ttyAMA0 115200
> # cat /etc/inittab > /dev/ttyAMA0 <- OK
I meant dmesg under barebox, if UART1 fails to output, but UART0 can be
read before the transceiver.
On 10/6/20 1:32 AM, Robert Carnecky (Neopsis) wrote:
> I played a bit more with the config.txt settings and when I activated the flag
>
> uart_2ndstage=1
>
> I got the barebox console! Here a snippet from the 2stage while
> logging the UART lading.
Oh. That would indicate that there is some sort of initialization missing.
uart_2ndstage=1 initializes the UART for VideoCore use apparently and from
there on, it works.
> What I do not understand: how the loaded /mfs/sd/bcm2710-rpi-cm3.dtb
> and the overlays
> cooperate with the Barebox device tree? Does it mean we have two sets
> of device tree
> files?
Yes. The VideoCore device tree is available in barebox as /vc.dtb,
see e390c8799d91 ("ARM: rpi: save fdt that was passed from VideoCore")
Hope this helps,
Ahmad
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
_______________________________________________
barebox mailing list
barebox@xxxxxxxxxxxxxxxxxxx
http://lists.infradead.org/mailman/listinfo/barebox
