From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-io1-xd35.google.com ([2607:f8b0:4864:20::d35]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kUdfQ-0004qV-UL for barebox@lists.infradead.org; Mon, 19 Oct 2020 22:30:15 +0000 Received: by mail-io1-xd35.google.com with SMTP id k6so1916252ior.2 for ; Mon, 19 Oct 2020 15:30:09 -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> <0c91c15c-91b6-98c0-1e3c-c02d5a19e772@pengutronix.de> In-Reply-To: <0c91c15c-91b6-98c0-1e3c-c02d5a19e772@pengutronix.de> From: "Robert Carnecky (Neopsis)" Date: Tue, 20 Oct 2020 00:29:57 +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 Mon, Oct 19, 2020 at 11:28 AM Ahmad Fatoum wrote: > > Hello, > > On 10/18/20 1:17 AM, Robert Carnecky (Neopsis) wrote: > > 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. > > 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. Robert Robert > > > > > 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 | > > > > -- > 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