nixpkgs/pkgs/misc/uboot/0001-rpi-Copy-properties-from-firmware-dtb-to-the-loaded-.patch

From 65d90cd17ad7cd3f9aeeb805a08be780fc5bae1a Mon Sep 17 00:00:00 2001
From: Sjoerd Simons <sjoerd@collabora.com>
Date: Sun, 22 Aug 2021 16:36:55 +0200
Subject: [PATCH] rpi: Copy properties from firmware dtb to the loaded dtb

The RPI firmware adjusts several property values in the dtb it passes
to u-boot depending on the board/SoC revision. Inherit some of these
when u-boot loads a dtb itself. Specificaly copy:

* /model: The firmware provides a more specific string
* /memreserve: The firmware defines a reserved range, better keep it
* emmc2bus and pcie0 dma-ranges: The C0T revision of the bcm2711 Soc (as
  present on rpi 400 and some rpi 4B boards) has different values for
  these then the B0T revision. So these need to be adjusted to boot on
  these boards
* blconfig: The firmware defines the memory area where the blconfig
  stored. Copy those over so it can be enabled.
* /chosen/kaslr-seed: The firmware generates a kaslr seed, take advantage
  of that.

Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>
Origin: https://patchwork.ozlabs.org/project/uboot/patch/20210822143656.289891-1-sjoerd@collabora.com/
---
 board/raspberrypi/rpi/rpi.c | 48 +++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c
index 372b26b6f2..64b8684b68 100644
--- a/board/raspberrypi/rpi/rpi.c
+++ b/board/raspberrypi/rpi/rpi.c
@@ -495,10 +495,58 @@ void *board_fdt_blob_setup(void)
 	return (void *)fw_dtb_pointer;
 }
 
+int copy_property(void *dst, void *src, char *path, char *property)
+{
+	int dst_offset, src_offset;
+	const fdt32_t *prop;
+	int len;
+
+	src_offset = fdt_path_offset(src, path);
+	dst_offset = fdt_path_offset(dst, path);
+
+	if (src_offset < 0 || dst_offset < 0)
+		return -1;
+
+	prop = fdt_getprop(src, src_offset, property, &len);
+	if (!prop)
+		return -1;
+
+	return fdt_setprop(dst, dst_offset, property, prop, len);
+}
+
+/* Copy tweaks from the firmware dtb to the loaded dtb */
+void  update_fdt_from_fw(void *fdt, void *fw_fdt)
+{
+	/* Using dtb from firmware directly; leave it alone */
+	if (fdt == fw_fdt)
+		return;
+
+	/* The firmware provides a more precie model; so copy that */
+	copy_property(fdt, fw_fdt, "/", "model");
+
+	/* memory reserve as suggested by the firmware */
+	copy_property(fdt, fw_fdt, "/", "memreserve");
+
+	/* Adjust dma-ranges for the SD card and PCI bus as they can depend on
+	 * the SoC revision
+	 */
+	copy_property(fdt, fw_fdt, "emmc2bus", "dma-ranges");
+	copy_property(fdt, fw_fdt, "pcie0", "dma-ranges");
+
+	/* Bootloader configuration template exposes as nvmem */
+	if (copy_property(fdt, fw_fdt, "blconfig", "reg") == 0)
+		copy_property(fdt, fw_fdt, "blconfig", "status");
+
+	/* kernel address randomisation seed as provided by the firmware */
+	copy_property(fdt, fw_fdt, "/chosen", "kaslr-seed");
+}
+
 int ft_board_setup(void *blob, struct bd_info *bd)
 {
 	int node;
 
+	update_fdt_from_fw(blob, (void *)fw_dtb_pointer);
+
 	node = fdt_node_offset_by_compatible(blob, -1, "simple-framebuffer");
 	if (node < 0)
 		lcd_dt_simplefb_add_node(blob);
-- 
2.32.0