diff options
Diffstat (limited to 'import-layers/meta-raspberrypi/recipes-bsp/u-boot/files/0002-rpi-passthrough-of-the-firmware-provided-FDT-blob.patch')
| -rw-r--r-- | import-layers/meta-raspberrypi/recipes-bsp/u-boot/files/0002-rpi-passthrough-of-the-firmware-provided-FDT-blob.patch | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/import-layers/meta-raspberrypi/recipes-bsp/u-boot/files/0002-rpi-passthrough-of-the-firmware-provided-FDT-blob.patch b/import-layers/meta-raspberrypi/recipes-bsp/u-boot/files/0002-rpi-passthrough-of-the-firmware-provided-FDT-blob.patch new file mode 100644 index 000000000..323b7ab40 --- /dev/null +++ b/import-layers/meta-raspberrypi/recipes-bsp/u-boot/files/0002-rpi-passthrough-of-the-firmware-provided-FDT-blob.patch @@ -0,0 +1,156 @@ +From ade243a211d62327e9ebadce27bbbff7981e37f0 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?C=C3=A9dric=20Schieli?= <cschieli@gmail.com> +Date: Fri, 11 Nov 2016 11:59:07 +0100 +Subject: [PATCH] rpi: passthrough of the firmware provided FDT blob +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Raspberry firmware used to pass a FDT blob at a fixed address (0x100), +but this is not true anymore. The address now depends on both the +memory size and the blob size [1]. + +If one wants to passthrough this FDT blob to the kernel, the most +reliable way is to save its address from the r2/x0 register in the +U-Boot entry point and expose it in a environment variable for +further processing. + +This patch just does this: +- save the provided address in the global variable fw_dtb_pointer +- expose it in ${fdt_addr} if it points to a a valid FDT blob + +There are many different ways to use it. One can, for example, use +the following script which will extract from the tree the command +line built by the firmware, then hand over the blob to a previously +loaded kernel: + +fdt addr ${fdt_addr} +fdt get value bootargs /chosen bootargs +bootz ${kernel_addr_r} - ${fdt_addr} + +Alternatively, users relying on sysboot/pxe can simply omit any FDT +statement in their extlinux.conf file, U-Boot will automagically pick +${fdt_addr} and pass it to the kernel. + +[1] https://www.raspberrypi.org/forums//viewtopic.php?f=107&t=134018 + +Upstream-Status: Backport + +Signed-off-by: Cédric Schieli <cschieli@gmail.com> +Acked-by: Stephen Warren <swarren@nvidia.com> +Signed-off-by: Jonathan Liu <net147@gmail.com> +--- + board/raspberrypi/rpi/Makefile | 1 + + board/raspberrypi/rpi/lowlevel_init.S | 36 +++++++++++++++++++++++++++++++++++ + board/raspberrypi/rpi/rpi.c | 29 ++++++++++++++++++++++++++++ + 3 files changed, 66 insertions(+) + create mode 100644 board/raspberrypi/rpi/lowlevel_init.S + +diff --git a/board/raspberrypi/rpi/Makefile b/board/raspberrypi/rpi/Makefile +index 4ce2c98..dcb25ac 100644 +--- a/board/raspberrypi/rpi/Makefile ++++ b/board/raspberrypi/rpi/Makefile +@@ -5,3 +5,4 @@ + # + + obj-y := rpi.o ++obj-y += lowlevel_init.o +diff --git a/board/raspberrypi/rpi/lowlevel_init.S b/board/raspberrypi/rpi/lowlevel_init.S +new file mode 100644 +index 0000000..cdbd8e1 +--- /dev/null ++++ b/board/raspberrypi/rpi/lowlevel_init.S +@@ -0,0 +1,36 @@ ++/* ++ * (C) Copyright 2016 ++ * Cédric Schieli <cschieli@gmail.com> ++ * ++ * SPDX-License-Identifier: GPL-2.0+ ++ */ ++ ++#include <config.h> ++ ++.align 8 ++.global fw_dtb_pointer ++fw_dtb_pointer: ++#ifdef CONFIG_ARM64 ++ .dword 0x0 ++#else ++ .word 0x0 ++#endif ++ ++/* ++ * Routine: save_boot_params (called after reset from start.S) ++ * Description: save ATAG/FDT address provided by the firmware at boot time ++ */ ++ ++.global save_boot_params ++save_boot_params: ++ ++ /* The firmware provided ATAG/FDT address can be found in r2/x0 */ ++#ifdef CONFIG_ARM64 ++ adr x8, fw_dtb_pointer ++ str x0, [x8] ++#else ++ str r2, fw_dtb_pointer ++#endif ++ ++ /* Returns */ ++ b save_boot_params_ret +diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c +index 6245b36..ffd6d31 100644 +--- a/board/raspberrypi/rpi/rpi.c ++++ b/board/raspberrypi/rpi/rpi.c +@@ -25,6 +25,9 @@ + + DECLARE_GLOBAL_DATA_PTR; + ++/* From lowlevel_init.S */ ++extern unsigned long fw_dtb_pointer; ++ + static const struct bcm2835_gpio_platdata gpio_platdata = { + .base = BCM2835_GPIO_BASE, + }; +@@ -285,6 +288,31 @@ static void set_fdtfile(void) + setenv("fdtfile", fdtfile); + } + ++/* ++ * If the firmware provided a valid FDT at boot time, let's expose it in ++ * ${fdt_addr} so it may be passed unmodified to the kernel. ++ */ ++static void set_fdt_addr(void) ++{ ++ if (getenv("fdt_addr")) ++ return; ++ ++ if (fdt_magic(fw_dtb_pointer) != FDT_MAGIC) ++ return; ++ ++ setenv_hex("fdt_addr", fw_dtb_pointer); ++} ++ ++/* ++ * Prevent relocation from stomping on a firmware provided FDT blob. ++ */ ++unsigned long board_get_usable_ram_top(unsigned long total_size) ++{ ++ if ((gd->ram_top - fw_dtb_pointer) > SZ_64M) ++ return gd->ram_top; ++ return fw_dtb_pointer & ~0xffff; ++} ++ + static void set_usbethaddr(void) + { + ALLOC_CACHE_ALIGN_BUFFER(struct msg_get_mac_address, msg, 1); +@@ -356,6 +384,7 @@ static void set_serial_number(void) + + int misc_init_r(void) + { ++ set_fdt_addr(); + set_fdtfile(); + set_usbethaddr(); + #ifdef CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG +-- +2.10.2 + |
