Finally, I managed to boot into barebox menu using UART1 (/dev/ttyS0) as the console. The solution was to remove all UART related overlays from config.txt and only activate UART1. enable_uart=1 Anyway, another problem occurred. When booting via barebox the CPU serial number is wrong. Obviously, barebox somehow manipulates the internal structures and cat /proc/cpuinfo returns always Hardware : BCM2835 Revision : 0000 Serial : 0000000000000000 Model : Raspberry Pi Compute Module 3 IO board V3.0 When I boot the same image directly without barebox boot loader, the info is OK. I found some discussions about U-Boot and wrong serial number here https://www.raspberrypi.org/forums/viewtopic.php?t=183474#p1162778 maybe that's barebox related too. Anyway, that is a definitive no go with barebox for us because parts of our software are expecting the unique serial number. Robert On Fri, Oct 9, 2020 at 4:18 PM Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx> wrote: > > 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
