On Tue, 2020-10-20 at 00:29 +0200, Robert Carnecky (Neopsis) wrote: > On Mon, Oct 19, 2020 at 11:28 AM Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx> wrote: > > Hello, > > > > On 10/18/20 1:17 AM, Robert Carnecky (Neopsis) wrote: > > > On Sat, Oct 17, 2020 at 11:29 PM Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx> wrote: > > > > Hi, > > > > > > > > On 10/17/20 1:31 PM, Robert Carnecky (Neopsis) wrote: > > > > > 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. > > > > > > > > I believe you can boot Linux with /vc.dtb and you'll get the same > > > > device tree passed to Linux as if you booted without passing through > > > > barebox. > > > > > > Yes, but then I lose my Linux console! A summary, in all cases Barebox device > > > tree in arch/arm/dts/bcm2837-rpi-cm3.dts was updated following your hint, e.g. > > > > > > / { > > > chosen { > > > stdout-path = "&uart1"; > > > }; > > > }; > > > > > > &uart1 { > > > pinctrl-names = "default"; > > > pinctrl-0 = <&uart1_gpio14>; > > > status = "okay"; > > > }; > > > > > > &uart0 { > > > pinctrl-names = "default"; > > > pinctrl-0 = <&uart0_gpio32>; > > > status = "okay"; > > > }; > > > > > > 1. Booting kernel direct, works as expected (console on uart1), > > > expected behavior > > > > > > kernel=zImage > > > enable_uart=1 > > > dtoverlay=uart0,txd0_pin=32,rxd0_pin=33,pin_func=7 > > > dtoverlay=uart1,txd1_pin=14,rxd1_pin=15 > > > > > > 2. With Barebox loader. The same config.txt as in case 1), > > > - no Barebox console > > > - kernel boots with the console on uart1 > > > > > > kernel=barebox-raspberry-pi-cm3.img > > > enable_uart=1 > > > dtoverlay=uart0,txd0_pin=32,rxd0_pin=33,pin_func=7 > > > dtoverlay=uart1,txd1_pin=14,rxd1_pin=15 > > > > > > 3. With Barebox loader, no uart overlays in config.txt. > > > - Barebox console on uart1 ok, > > > - kernel console on uart1 > > > - almost done), but ... no cpuinfo > > > > > > kernel=barebox-raspberry-pi-cm3.img > > > enable_uart=1 > > > > > > 4. With Barebox loader, no uart overlays in config.txt, Linux boots with vc.dtb. > > > - Barebox console on uart1 ok > > > - no Linux console, Linux boots with cpuinfo ok > > > > > > kernel=barebox-raspberry-pi-cm3.img > > > enable_uart=1 > > > > > > I did not found any combination when I get the Barebox console and > > > Linux console on uart1 > > > and with cpuinfo ok. If the serial number is not needed, case 3) should be ok. > > > > What happens if you combine 2. and 4. ? > > So you have enable_uart=1, the uart overlays _and_ Linux boots with vc.dtb? > > Negativ. Whenever I enable overlays in the config.txt that map uart0 > to pin32/33 and > uart1 to pin 14/15 (console), I do not get Barebox console. It does > not depend on the device > tree passed to the kernel. This interaction between Barebox device > tree and Raspberry config.txt > overlays is a bit strange for me. > > Just an idea - does Barebox fully support this hardware? From the 2835 > ARM Peripherals Guide, > chapter 2.2 miniUART : > > > The implemented UART is not a 16650 compatible UART However as far as possible > > the first 8 control and status registers are laid out like a 16550 UART. Al 16550 register > > bits which are not supported can be written but will be ignored and read back as 0. > > All control bits for simple UART receive/transmit operations are available. > > Barebox has support for NS16650 ( CONFIG_DRIVER_SERIAL_NS16550) but not for > Raspberry miniUART. > > Anyway, I am giving up. I am sure I tested all combinations of > overlays, I have written my > own dts, nothing works as I need (console=uart1, incl. proper serial > number handling). > There is no problem to get the console on uart0/ttyAMA0, but not on uart1/ttyS0. > The Raspberry way how they are handling uarts lacks all logic and is completely > unclear. Hi, looking into arch/arm/dts/bcm2837-rpi-cm3.dts: / { chosen { stdout-path = &uart0; }; }; The CM3 module is currently default configured to use uart0 as the stdout path, while bcm2837-rpi-3.dts is configured for uart1. This was done in ab76f9d09d3b7b77fc00d84bc2fac6bfbf82c69c after the miniuart support was added to the NS16550 driver in 77de547cd179b910cdcb8530df15d77a0fc66a3c. Changing the stdout-path for the barebox internal device tree should output barebox correctly on the miniuart console. Regards, Rouven Czerwinski _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
