From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-il1-x131.google.com ([2607:f8b0:4864:20::131]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kTvSQ-00084g-CJ for barebox@lists.infradead.org; Sat, 17 Oct 2020 23:17:52 +0000 Received: by mail-il1-x131.google.com with SMTP id w17so6701896ilg.8 for ; Sat, 17 Oct 2020 16:17:49 -0700 (PDT) MIME-Version: 1.0 References: <61631575-54f8-4fe1-4a25-a806b39f2a63@pengutronix.de> <0fae6213-91b3-a3ae-e1b8-2c7752866b2a@pengutronix.de> <169904de-d6d7-b3c8-79ce-e3e63305f037@pengutronix.de> In-Reply-To: <169904de-d6d7-b3c8-79ce-e3e63305f037@pengutronix.de> From: "Robert Carnecky (Neopsis)" Date: Sun, 18 Oct 2020 01:17:36 +0200 Message-ID: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: Mini UART on RaspberryPi CM3/CM3+ To: Ahmad Fatoum Cc: barebox@lists.infradead.org On Sat, Oct 17, 2020 at 11:29 PM Ahmad Fatoum 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. Robert > > > > > Robert > > > > > > On Fri, Oct 9, 2020 at 4:18 PM Ahmad Fatoum 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 | > > > > -- > 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@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox