Support for Raspberry Pi 3B (BCM2837)

The BCM2837 core is used not just in the RPi 3B but also in the Zero 2W, both device trees have been added to the board config. The BCM2711 support has been extended to include RPi 400 and CM4 I/O. To support the BCM2837 family more firmware options habe been enabled, since the RPi3 does not have bootcode.bin flashed in the SoC. The SD card image now uses a hybrid GPT/MBR format so the RPi3 bootcode.bin can read all files from the first VFAT partition. The default device tree for Linux is now chosen by the U-Boot probe and the only exception is the "laundry room" detector that looks for a RPi4 with a 7" touch screen, which then selects the DSI enabled RPi4 variant. This is enough to properly load an RPi 3B and a CM4 based router board. The BCM2837 does not have PCI/PCIe or a built-in MAC so it relies on the USB to Ethernet LAN78xx which does not support disabling pause frames. I have opted for checking for EOPNOTSUPP instead of adding yet another quirk, because it is likely to be a common limitation of more drivers and chipsets, and this code is best-effort anyway. Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
2026-08-02 22:03:01 +02:00 · 2025-10-31 13:25:59 +01:00
parent 937d4c38c7
commit 9b057ad547
15 changed files with 104 additions and 49 deletions
@@ -14,6 +14,9 @@ BR2_SYSTEM_BIN_SH_NONE=y
 BR2_ROOTFS_POST_IMAGE_SCRIPT="${BR2_EXTERNAL_INFIX_PATH}/board/common/post-image.sh"
 # BR2_PACKAGE_BUSYBOX is not set
 BR2_PACKAGE_RPI_FIRMWARE=y
+BR2_PACKAGE_RPI_FIRMWARE_BOOTCODE_BIN=y
+BR2_PACKAGE_RPI_FIRMWARE_VARIANT_PI=y
+BR2_PACKAGE_RPI_FIRMWARE_VARIANT_PI_X=y
 BR2_PACKAGE_RPI_FIRMWARE_VARIANT_PI4=y
 BR2_PACKAGE_RPI_FIRMWARE_VARIANT_PI4_X=y
 BR2_PACKAGE_RPI_FIRMWARE_CONFIG_FILE="${BR2_EXTERNAL_INFIX_PATH}/src/board/raspberry-pi-4/config.txt"
@@ -22,6 +22,7 @@ define RASPBERRY_PI_4_LINUX_CONFIG_FIXUPS
 	$(call KCONFIG_SET_OPT,CONFIG_BRCMFMAC,m)
 	$(call KCONFIG_ENABLE_OPT,CONFIG_BRCMFMAC_SDIO)
 	$(call KCONFIG_SET_OPT,CONFIG_I2C_BCM2835,m)
+	$(call KCONFIG_SET_OPT,CONFIG_BCM2835_THERMAL,m)
 	$(call KCONFIG_SET_OPT,CONFIG_BCM2711_THERMAL,m)
 	$(call KCONFIG_ENABLE_OPT,CONFIG_MMC_BCM2835)
 	$(call KCONFIG_ENABLE_OPT,CONFIG_MMC_SDHCI_IPROC)
@@ -1,43 +1,35 @@
-# Please note that this is only a sample, we recommend you to change it to fit
-# your needs.
-# You should override this file using BR2_PACKAGE_RPI_FIRMWARE_CONFIG_FILE.
-# See http://buildroot.org/manual.html#rootfs-custom
-# and http://elinux.org/RPiconfig for a description of config.txt syntax
+[all]
+arm_64bit=1

-start_file=start4.elf
-fixup_file=fixup4.dat
+arm_boost=1
+force_turbo=1

 kernel=u-boot.bin

-device_tree=bcm2711-rpi-4-b.dtb
 dtoverlay=rpi-env
 dtoverlay=infix-key
+
+disable_overscan=1
+
+enable_uart=1
+uart_2ndstage=1
+
+[pi3]
+start_file=start.elf
+fixup_file=fixup.dat
+
+dtoverlay=miniuart-bt
+
+gpu_mem=100
+
+[pi4]
+start_file=start4.elf
+fixup_file=fixup4.dat
+
 dtoverlay=vc4-kms-v3d-pi4
 lcd_rotate=2

-
 # Prevent console on DSI
 console=map:0

-# To use an external initramfs file
-#initramfs rootfs.cpio.gz
-
-# Disable overscan assuming the display supports displaying the full resolution
-# If the text shown on the screen disappears off the edge, comment this out
-disable_overscan=1
-
 gpu_mem=256
-
-# Enable UART0 for serial console on ttyAMA0
-enable_uart=1
-force_turbo=1
-#dtoverlay=miniuart-bt
-
-# Run as fast as firmware / board allows
-arm_boost=1
-
-# enable 64bits support
-arm_64bit=1
-
-# Enable early debugging info
-uart_2ndstage=1
@@ -1 +1,3 @@
-dtb-y += broadcom/bcm2711-rpi-4-b.dtb broadcom/bcm2711-rpi-4-b-dsi.dtb
+dtb-y += broadcom/bcm2837-rpi-3-b.dtb broadcom/bcm2837-rpi-zero-2-w.dtb \
+	 broadcom/bcm2711-rpi-4-b.dtb broadcom/bcm2711-rpi-4-b-dsi.dtb  \
+	 broadcom/bcm2711-rpi-400.dtb broadcom/bcm2711-rpi-cm4-io.dtb
@@ -1,4 +1,5 @@
 #include <arm64/broadcom/bcm2711-rpi-4-b.dts>
+#include "infix.dtsi"

 / {
 	/* Dynamic GPU reservation */
@@ -21,11 +22,6 @@
 	chosen {
 		/* 8250 auxiliary UART instead of pl011 */
 		stdout-path = "serial1:115200n8";
-
-		infix {
-			/* Default admin user password: 'admin' */
-			factory-password-hash = "$5$mI/zpOAqZYKLC2WU$i7iPzZiIjOjrBF3NyftS9CCq8dfYwHwrmUK097Jca9A";
-		};
 	};
 };

@@ -0,0 +1,9 @@
+#include <arm64/broadcom/bcm2711-rpi-400.dts>
+#include "infix.dtsi"
+
+/ {
+	chosen {
+		/* 8250 auxiliary UART instead of pl011 */
+		stdout-path = "serial1:115200n8";
+	};
+};
@@ -0,0 +1,9 @@
+#include <arm64/broadcom/bcm2711-rpi-cm4-io.dts>
+#include "infix.dtsi"
+
+/ {
+	chosen {
+		/* 8250 auxiliary UART instead of pl011 */
+		stdout-path = "serial1:115200n8";
+	};
+};
@@ -0,0 +1,9 @@
+#include <arm64/broadcom/bcm2837-rpi-3-b.dts>
+#include "infix.dtsi"
+
+/ {
+	chosen {
+		/* 8250 auxiliary UART instead of pl011 */
+		stdout-path = "serial1:115200n8";
+	};
+};
@@ -0,0 +1,9 @@
+#include <arm64/broadcom/bcm2837-rpi-zero-2-w.dts>
+#include "infix.dtsi"
+
+/ {
+	chosen {
+		/* 8250 auxiliary UART instead of pl011 */
+		stdout-path = "serial1:115200n8";
+	};
+};
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Common Infix OS defaults
+ */
+
+/ {
+	chosen {
+		infix {
+			/* Default admin user password: 'admin' */
+			factory-password-hash = "$5$mI/zpOAqZYKLC2WU$i7iPzZiIjOjrBF3NyftS9CCq8dfYwHwrmUK097Jca9A";
+		};
+	};
+};
@@ -31,41 +31,41 @@ image var.ext4 {

 image #INFIX_ID##VERSION#-rpi4-sdcard.img {
 	hdimage {
-		partition-table-type = "gpt"
+		partition-table-type = "hybrid"
 	}

 	partition boot {
-		partition-type-uuid = EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
+		partition-type = 0xc
 		bootable = "true"
 		image = "boot.vfat"
 	}

 	partition aux {
-		partition-uuid = D4EF35A0-0652-45A1-B3DE-D63339C82035
+		partition-type-uuid = srv
 		image = "aux.ext4"
 	}

 	partition primary {
-		partition-type-uuid = 0FC63DAF-8483-4772-8E79-3D69D8477DE4
-		bootable = true
+		partition-type-uuid = linux
+		bootable = "true"
 		size = 250M
 		image = "rootfs.squashfs"
 	}

 	partition secondary {
-		partition-type-uuid = 0FC63DAF-8483-4772-8E79-3D69D8477DE4
-		bootable = true
+		partition-type-uuid = linux
+		bootable = "true"
 		size = 250M
 		image = "rootfs.squashfs"
 	}

 	partition cfg {
-		partition-uuid = 7aa497f0-73b5-47e5-b2ab-8752d8a48105
+		partition-type-uuid = srv
 		image = "cfg.ext4"
 	}

 	partition var {
-		partition-uuid = 8046A06A-E45A-4A14-A6AD-6684704A393F
+		partition-type-uuid = var
 		image = "var.ext4"
 	}
 }
@@ -0,0 +1 @@
+raspberrypi,4-model-b
@@ -133,7 +133,7 @@
    }
  },
  "ietf-system:system": {
-    "hostname": "rpi4",
+    "hostname": "rpi",
    "ntp": {
      "enabled": true,
      "server": [
@@ -17,7 +17,7 @@
 			stdin = "serial";
 			splashpos = "m,m";
 			splashfile = "splash.bmp";
-			checkdisplay = "if testrpidisplay; then; setenv fdtfile broadcom/bcm2711-rpi-4-b-dsi.dtb; else; setenv fdtfile broadcom/bcm2711-rpi-4-b.dtb; fi";
+			checkdisplay = "if testrpidisplay; then; setenv fdtfile broadcom/bcm2711-rpi-4-b-dsi.dtb; fi";
 			bootcmd = "fatload mmc 0:1 ${loadaddr} ${splashfile}; bmp display ${loadaddr}; run checkdisplay; run ixboot";

 			ixpreboot     = /incbin/("scripts/ixpreboot.sh");
@@ -45,8 +45,19 @@ static int netdag_gen_ethtool_flow_control(struct dagger *net, struct lyd_node *
 	if (!fp)
 		return -EIO;
 	fprintf(fp, "[[ -n $(ethtool --json %s | jq '.[] | select(.\"supported-pause-frame-use\" == \"No\")') ]] && exit 0\n", ifname);
-	fprintf(fp, "ethtool --pause %s autoneg %s rx off tx off\n",
-		ifname, iface_uses_autoneg(cif) ? "on" : "off");
+
+	/*
+	 * Some NICs report "supported-pause-frame-use": "Symmetric Receive-only", like
+	 * RPi 3B's LAN78xx USB to Ethernet controller, but the drivers do not support
+	 * disabling it.  This call is best effort after all, so we capture and check
+	 * the error.  If the operation is not supported, we log it and exit cleanly.
+	 */
+	fprintf(fp,
+		"if ! err=$(ethtool --pause %s autoneg %s rx off tx off 2>&1); then\n"
+		"    logger -it confd -p daemon.error \"%s: failed disabling flow-control\"\n"
+		"    echo \"$err\" | grep -q \"Operation not supported\" && exit 0\n"
+		"fi\n",
+		ifname, iface_uses_autoneg(cif) ? "on" : "off", ifname);
 	fclose(fp);

 	return 0;