Raspberrypi CM3, u-boot console and kernel patch

Home Messages Hashtags Subgroups

#51558

Raspberrypi CM3, u-boot console and kernel patch
#raspberrypi #dunfell #kernel #rpi #cm3

Romain Crausaz <romain.crausaz@...> #51558 Dear all, I have 4 different topics on which I can't find a correct answer on internet. I am developing a new system base on the Raspberrypi CM3+ with our custom board. I am using Yocto with the meta-raspberrypi and the dunfell branch (for LTS) Here is what I would like to achieve: Get UART0 or UART1 as the standard console for u-boot and the linux kernel on pins 32 and 33 Make u-boot pass my device tree (stored in the boot partition) to the kernel and not the device tree generated by the first stage bootloader U-boot message ? Patch kernel which sources are in work-shared -------------------------------------------------------------------------------------------------------------------------------------- Regarding the first point, I already created a new device tree within u-boot and set it as the default bootloader in my default config. I have some troubles to understand how everything works between the first stage bootloader, u-boot, u-boot internal device tree and the kernel device tree. Here is the different things I tried: Use UART0 on pins 32 and 33 In the u-boot device tree: chosen { stdout-path = "serial0:115200n8"; } ... &uart0 { pinctrl-names= "default"; pinctrl-0 = <&uart0_gpio32>; status = "okay"; } In the config.txt: enable_uart=1 dtoverlay=uart0,txd0_pin=32,rxd0_pin=33,pin_func=7 This works but only for the kernel, I don't get any output from u-boot and can't stop the boot process. Use UART1 on pins 32 and 33: more or less the same modification but with different values (uart1_gpio32, serial1, etc..) and same results I would like to know if there is an other file I should modify to get this working. When I use the uart0 or uart1 on pin 14 and 15 everything works perfectly. Here is my device tree patch for u-boot: diff --git a/arch/arm/dts/bcm2837-rpi-cm3-digisens.dts b/arch/arm/dts/bcm2837-rpi-cm3-digisens.dts index e69de29bb2..f6c0efd18d 100644 --- a/arch/arm/dts/bcm2837-rpi-cm3-digisens.dts +++ b/arch/arm/dts/bcm2837-rpi-cm3-digisens.dts @@ -0,0 +1,175 @@ +// SPDX-License-Identifier: GPL-2.0 +/dts-v1/; +#include "bcm2837.dtsi" +#include "bcm2836-rpi.dtsi" +#include "bcm283x-rpi-smsc9514.dtsi" +#include "bcm283x-rpi-usb-host.dtsi" + +/ { + compatible = "raspberrypi,3-compute-module", "brcm,bcm2837"; + model = "Raspberry Pi Compute Module 3 DIGI-SENS baseboard"; + + memory@0 { + reg = <0 0x40000000>; + }; + + leds { + act { + gpios = <&expgpio 2 GPIO_ACTIVE_HIGH>; + }; + }; + + chosen { + /* 8250 auxiliary UART instead of pl011 / + stdout-path = "serial1:115200n8"; + }; + + reg_3v3: fixed-regulator { + compatible = "regulator-fixed"; + regulator-name = "3V3"; + regulator-min-microvolt = <3300000>; + regulator-max-microvolt = <3300000>; + regulator-always-on; + }; + + reg_1v8: fixed-regulator { + compatible = "regulator-fixed"; + regulator-name = "1V8"; + regulator-min-microvolt = <1800000>; + regulator-max-microvolt = <1800000>; + regulator-always-on; + }; +}; + +&firmware { + expgpio: gpio { + compatible = "raspberrypi,firmware-gpio"; + gpio-controller; + #gpio-cells = <2>; + gpio-line-names = "HDMI_HPD_N", + "EMMC_EN_N", + "NC", + "NC", + "NC", + "NC", + "NC", + "NC"; + status = "okay"; + }; +}; + +&hdmi { + hpd-gpios = <&expgpio 1 GPIO_ACTIVE_LOW>; +}; + +&uart1 { + pinctrl-names = "default"; + pinctrl-0 = <&uart0_gpio32>; + status = "okay"; +}; + + +&sdhost { + pinctrl-names = "default"; + pinctrl-0 = <&sdhost_gpio48>; + bus-width = <4>; + vmmc-supply = <&reg_3v3>; + vqmmc-supply = <&reg_1v8>; + status = "okay"; +}; (in my defconfig for u-boot I have the following default device tree parameter: +CONFIG_DEFAULT_DEVICE_TREE="bcm2837-rpi-cm3-digisens") -------------------------------------------------------------------------------------------------------------------------------------- The second point seems pretty clear to me. I will change the bootscript and load the file with the fatload command and pass it to the kernel. However I wonder if it might create some problems if the first stage bootloader has already reserved the pins. -------------------------------------------------------------------------------------------------------------------------------------- When u-boot is starting correctly (for the moment only on pin 14 and 15) I have the following warning and I was not able to find any explanation about it: U-Boot 2020.01 (Jan 06 2020 - 20:56:31 +0000) DRAM: 948 MiB RPI Compute Module 3+ (0xa02100) MMC: mmc@7e202000: 0 Loading Environment from FAT... WARNING at drivers/mmc/bcm2835_sdhost.c:410/bcm2835_send_command()! WARNING at drivers/mmc/bcm2835_sdhost.c:410/bcm2835_send_command()!* * Warning - bad CRC, using default environment In: serial Out: vidconsole Err: vidconsole Net: No ethernet found. starting USB... Bus usb@7e980000: scanning bus usb@7e980000 for devices... 1 USB Device(s) found scanning usb for storage devices... 0 Storage Device(s) found Hit any key to stop autoboot: 0 WARNING at drivers/mmc/bcm2835_sdhost.c:410/bcm2835_send_command()! WARNING at drivers/mmc/bcm2835_sdhost.c:410/bcm2835_send_command()!** switch to partitions #0, OK mmc0(part 0) is current device Scanning mmc 0:1... Found U-Boot script /boot.scr Should I simply ignore it ? -------------------------------------------------------------------------------------------------------------------------------------- Finally I have some troubles when I try to patch the kernel. I have always been working with IMX SOC and (Karo-electronics bsp). With the meta-raspberry, the kernel sources are in the work-shared directory. When I create a patch with for example this command: git diff arch/arm/boot/dts/overlays/uart0-cm3-overlay.dts > /.../0001-uart0.patch I have the following error when I run bitbake: "Patch failures can be resolved in the linux source directory" -------------------------------------------------------------------------------------------------------------------------------------- Thank you in advance for your time. Let me know if you need more information. Best regards Romain
More All Messages By This Member

#51558

Join yocto@lists.yoctoproject.org to automatically receive all group messages.

Home Messages Hashtags Subgroups Terms