-----Original Message----- From: U-Boot u-boot-bounces@lists.denx.de On Behalf Of Simon Glass Sent: Tuesday, December 10, 2024 4:55 AM To: U-Boot Mailing List u-boot@lists.denx.de Cc: Tom Rini trini@konsulko.com; Stephen Warren swarren@wwwdotorg.org; Stephen Warren swarren@nvidia.com; Matthias Brugger mbrugger@suse.com; Simon Glass sjg@chromium.org; Francois Berder fberder@outlook.fr; Ivan T. Ivanov iivanov@suse.de; Patrick Rudolph patrick.rudolph@9elements.com; Peter Robinson pbrobinson@gmail.com; Rasmus Villemoes rasmus.villemoes@prevas.dk Subject: [PATCH v3 5/5] rpi: Use the U-Boot control FDT for fdt_addr
The fdt_addr variable is used in extlinux as a fallback devicetree if none is provided by the boot command.
The existing mechanism uses the devicetree provided to U-Boot, but in its original, unrelocated position. For the rpi_4 I am using, this is at 2b35ef00 which is not a convenient place in memory, if the ramdisk is large.
U-Boot already deals with this sort of problem by relocating the FDT to a safe address.
So use the control-FDT address instead.
Remove the existing comment, which is confusing, since the FDT is not actually passed unmodified to the kernel: U-Boot adds various things using its FDT-fixup mechanism.
Note that board_get_usable_ram_top() reduces the RAM top for boards with less RAM. This behaviour is left unchanged as there is no other mechanism for U-Boot to handle this.
In version 2, it incorporates some changes to fdt_addr, etc. suggested by Tom, as well as adding myself as a maintainer.
Signed-off-by: Simon Glass sjg@chromium.org
Reviewed-by: Jaehoon Chung jh80.chung@samsung.com Tested-by: Jaehoon Chung jh80.chung@samsung.com
(no changes since v2)
Changes in v2:
- Drop patch to allow expanding the devicetree during relocation
board/raspberrypi/rpi/rpi.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-)
diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c index 9122f33d88d..8f6ab1b1b9b 100644 --- a/board/raspberrypi/rpi/rpi.c +++ b/board/raspberrypi/rpi/rpi.c @@ -3,6 +3,8 @@
- (C) Copyright 2012-2016 Stephen Warren
*/
+#define LOG_CATEGORY LOGC_BOARD
#include <config.h> #include <dm.h> #include <env.h> @@ -325,19 +327,10 @@ static void set_fdtfile(void) env_set("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.
- */
+/* Allow U-Boot to use its control FDT with extlinux if one is not provided */ static void set_fdt_addr(void) {
- if (env_get("fdt_addr"))
return;- if (fdt_magic(fw_dtb_pointer) != FDT_MAGIC)
return;- env_set_hex("fdt_addr", fw_dtb_pointer);
- env_set_hex("fdt_addr", (ulong)gd->fdt_blob);
}
/* @@ -572,7 +565,10 @@ int ft_board_setup(void *blob, struct bd_info *bd) { int node;
- update_fdt_from_fw(blob, (void *)fw_dtb_pointer);
if (blob == gd->fdt_blob)
log_debug("Same FDT: nothing to do\n");else
update_fdt_from_fw(blob, (void *)gd->fdt_blob);node = fdt_node_offset_by_compatible(blob, -1, "simple-framebuffer"); if (node < 0)
-- 2.34.1