Hi Simon.
On Mon, 16 Dec 2024 at 00:27, Simon Glass sjg@chromium.org wrote:
Hi Peter,
On Wed, 11 Dec 2024 at 09:36, Peter Robinson pbrobinson@gmail.com wrote:
On Mon, 9 Dec 2024 at 19:55, Simon Glass sjg@chromium.org wrote:
The fdt_addr variable is used in extlinux as a fallback devicetree if none is provided by the boot command.
And what about where extlinux isn't used?
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.
Please re-word the above, it doesn't make sense to me, "the rpi_4 I am
using" .... what about the other millions of RPis out there?
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.
Don't remove it, re-word it so it's up to date.
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.
The below looks irrelevant to the patch at hand, it looks like it should
be in the cover letter.
Do you have any comments on the code in this series?
I did already comment on it, please go back through your emails ;-)
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
(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");elseupdate_fdt_from_fw(blob, (void *)gd->fdt_blob); node = fdt_node_offset_by_compatible(blob, -1,"simple-framebuffer");
if (node < 0)-- 2.34.1
Regards, Simon