On Fri, Jun 18, 2021 at 03:15:32PM +0200, Konstantin Kletschke wrote: > > > > In the end it goes down to putting an entry like this into > > loader/entries/foo.conf into your rootfs: > > I will investigate this definitely carefully since this has nice advantages > controlling the boot from userspace, especially in order to gain a proper > failover environment. > > Meanwhile I realized I most probably have no problem with barebox and > dtb/dtbo handling. At least it _is_ preparing “my” dtbo files and trying to > handle them. > > In my initial mail regarding this thread I mentioned how this works on my > Beaglebones when I kept the delivered debian environment with u-boot. > The goal is to have the serial lines enabled as serial after bootup on the > pinheaders and there > this works with those dtbo files. Also I realized I can omit them and bitbang > in the GPIO multiplex mechanism below /sys/platform/... to gain the same > effect. Because the debian kernel setup (including the dtb file?) is enabling all > four serial lines at boot, regardless what I do: > > [ 0.952482] 44e09000.serial: ttyS0 at MMIO 0x44e09000 (irq = 30, base_baud = 3000000) is a 8250 > [ 1.713812] console [ttyS0] enabled > [ 1.718482] 48022000.serial: ttyS1 at MMIO 0x48022000 (irq = 31, base_baud = 3000000) is a 8250 > [ 1.728498] 48024000.serial: ttyS2 at MMIO 0x48024000 (irq = 32, base_baud = 3000000) is a 8250 > [ 1.738387] 481a6000.serial: ttyS3 at MMIO 0x481a6000 (irq = 33, base_baud = 3000000) is a 8250 > [ 1.748351] 481a8000.serial: ttyS4 at MMIO 0x481a8000 (irq = 34, base_baud = 3000000) is a 8250 > [ 1.758188] 481aa000.serial: ttyS5 at MMIO 0x481aa000 (irq = 35, base_baud = 3000000) is a 8250 > > The dtbo files only do some GPIO multiplexing (I realized yesterday). > > In my kernel setup only the first serial interface gets enabled: > > [ 0.734644] 44e09000.serial: ttyO0 at MMIO 0x44e09000 (irq = 29, base_baud = 3000000) is a OMAP UART0 > [ 1.303154] printk: console [ttyO0] enabled > > Maybe the overlays are not working since there are referring to not enabled serial interfaces, > like "target = <&uart1>;” for example? I am still investigating where differences between my > rather vanilla setup and the debian changes are... > > > >> Loading ARM Linux zImage '/boot/uImage' > >> Loading devicetree from '/boot/am335x-boneblack.dtb' > >> ERROR: of_resolver: __symbols__ missing from base devicetree > >> WARNING: Failed to fixup node in of_overlay_fixup+0x1/0x4: Invalid argument > >> ERROR: of_resolver: __symbols__ missing from base devicetree > >> WARNING: Failed to fixup node in of_overlay_fixup+0x1/0x4: Invalid argument > > > > You have to compile the device tree with -@ passed to dtc. If you are > > building the device tree in the Kernel this does the trick: > > > > make dtbs DTC_FLAGS=-@ > > I prepared a kernel (usually I use yocto, I did not found where to apply flags for “make dtbs” so I > prepared a test setup) and dtbo files this way. The compile process spits many warnings and the > resulting binary size increases, but the error “[…] Invalid argument" is identical. Have a look at the generated dtb file with 'dtc -I dtb -O dts <file>'. It should contain a __symbols__ node. BTW do you have a good reason to use overlays? Overlays only have a value when you have different hardware variants in which different overlays are loaded. If that's not the case I'd just go with a static devicetree and be done with it. Sascha -- 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
