[U-Boot-Users] [PATCH] Fix initrd booting
Jerry Van Baren
gvb.uboot at gmail.com
Tue Aug 7 15:54:57 CEST 2007
Hi Andy,
I'm not sure if you are aiming this at u-boot-fdt, which would be
logical, or if you are aiming this at u-boot-testing (or other). Care
to clarify?
Andy Fleming wrote:
> The device tree needs to be passed to Linux within CFG_BOOTMAPSZ.
> The current code places the device tree right before the initrd
> if it exists, and that will usually be closer to the end of
> memory. Instead, we should always put the device tree right
> before the bd_info structure, thus ensuring it is within
> CFG_BOOTMAPSZ.
>
> We do, however, allow for FDTs in uImages to shoot themselves in
> the foot by requesting a location outside of CFG_BOOTMAPSZ.
>
> Signed-off-by: Andy Fleming <afleming at freescale.com>
> ---
> common/cmd_bootm.c | 20 ++++++++------------
> 1 files changed, 8 insertions(+), 12 deletions(-)
>
> diff --git a/common/cmd_bootm.c b/common/cmd_bootm.c
> index a6499e8..d12ef76 100644
> --- a/common/cmd_bootm.c
> +++ b/common/cmd_bootm.c
> @@ -753,10 +753,7 @@ do_bootm_linux (cmd_tbl_t *cmdtp, int flag,
> #else
> if (*(ulong *)of_flat_tree == OF_DT_HEADER) {
> #endif
> -#ifndef CFG_NO_FLASH
> - if (addr2info((ulong)of_flat_tree) != NULL)
> - of_data = (ulong)of_flat_tree;
> -#endif
> + of_data = (ulong)of_flat_tree;
Is this right? The logic in bootm *in general* and specifically here is
hard to figure out, but the way I'm puzzling it out...
1) If of_data is *not* NULL, it is used as the indicator that the blob
must be relocated.
2) The above is saying that, if there is flash (not defined CFG_NO_FLASH
gaak) and if of_flat_tree points into flash (addr2info returns a
pointer), then of_data is set which makes #1 true.
As I read it, this causes the blob to be copied to RAM if it is in
flash, which is necessary since we cannot add/rewrite nodes and
properties in a flash copy.
Your change causes the blob to _always_ be relocated. Not necessarily
bad, but is it always good? I'm not a bootm expert by any means, and I
suspect the complexity grew substantially over time, but in the mucking
about I did, I did not dare to change the logic. :-/
> } else if (ntohl(hdr->ih_magic) == IH_MAGIC) {
> printf("## Flat Device Tree Image at %08lX\n", hdr);
> print_image_hdr(hdr);
[snip]
Thanks,
gvb
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