Re: Beaglebone white: Kernel doesn't start with barebox-2014.03.0

[Rolf Evers-Fischer <embedded24@evers-fischer.de>]

Hi Lukasz and Uwe,

> Lucas Stach <dev@lynxeye.de> hat am 21. April 2014 um 17:24 geschrieben:
>
>
> Am Mittwoch, den 16.04.2014, 22:02 +0200 schrieb Uwe Kleine-König:
> > On Wed, Apr 16, 2014 at 05:35:52PM +0200, Lucas Stach wrote:
> > > Hi Rolf,
> > >
> > > Am Dienstag, den 15.04.2014, 13:28 +0200 schrieb Rolf Evers-Fischer:
> > > > Dear all,
> > > > after update to barebox-2014.03.0, the kernel on my beaglebone-white
> > > > doesn't
> > > > start anymore.
> > > > The last line, which appears, is "booting kernel with devicetree".
> > > > I discovered that the problem is caused by the commit [1]. When I revert
> > > > this
> > > > commit, everything works fine.
> > > >
> > > > Here is some more info, which I gathered with additional printfs:
> > > > Without this commit, the '__do_bootm_linux()' function is called with
> > > > data->initrd_address = 0xffffffff
> > > > data->os_res->start = 0x80008000
> > > > data->os_entry = 0
> > > > swap = 0
> > > > Finally it invokes the 'start_linux()' function with
> > > > kernel = 0x80008000
> > > > swap = 0
> > > > initrd_start = 0x80808000
> > > > initrd_size = 0
> > > > data->oftree = 0x8b1e0000
> > > >
> > > > With this commit (i.e. when the kernel doesn't start), the
> > > > '__do_bootm_linux()'
> > > > function is called with the same parameters as above plus
> > > > free_mem = 0x8041f000
> > > > It invokes the 'start_linux()' function with
> > > > kernel = 0x80008000
> > > > swap = 0
> > > > initrd_start = 0x8041f000
> > > > initrd_size = 0
> > > > data->oftree = 0x8041f000
> > > >
> > > > Do you have any idea, how to fix this problem? For now I will continue
> > > > using
> > > > barebox-2014.03.0 without the problematic commit.
> > > >
> > > > [1] http://www.spinics.net/lists/u-boot-v2/msg17345.html
> > > > "ARM: bootm: pass free memory to __do_bootm_linux"
> > >
> > > I think you are trying to boot a uImage. Is this right?
> > >
Yes, I've tried to boot a uImage.

> > > Could you please test with a zImage? If it still fails, can you try the
> > > following patch?
> > >
> > > --------------------------------->8------------------------------------------
> > > From 6e51388bda025508b28d723960055656fa50784d Mon Sep 17 00:00:00 2001
> > > From: Lucas Stach <l.stach@pengutronix.de>
> > > Date: Wed, 16 Apr 2014 17:23:33 +0200
> > > Subject: [PATCH] ARM: bootm: be more clever while deciding where to put
> > > zImage
> > >
> > > For small systems we would put the zImage at 8MiB after
> > > the start of memory, and put the DT a bit after the zImage.
> > > When we encounter an image which is bigger than 8MiB
> > > uncompressed, the kernel would try to relocate itself
> > > and overwrite the DT.
> > >
> > > Try to be more clever at zImage placement to avoid
> > > triggering the kernel relocation.
> > >
> > > Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
> > > ---
> > > arch/arm/lib/bootm.c | 31 ++++++++++++++-----------------
> > > 1 file changed, 14 insertions(+), 17 deletions(-)
> > >
> > > diff --git a/arch/arm/lib/bootm.c b/arch/arm/lib/bootm.c
> > > index c63cbc02e35f..2d4b18b7f794 100644
> > > --- a/arch/arm/lib/bootm.c
> > > +++ b/arch/arm/lib/bootm.c
> > > @@ -245,23 +245,6 @@ static int do_bootz_linux(struct image_data *data)
> > > if (ret)
> > > return ret;
> > >
> > > - if (load_address == UIMAGE_INVALID_ADDRESS) {
> > > - /*
> > > - * The kernel should stay in the first 128MiB of RAM, recommended
> > > - * is 32MiB into RAM so that relocation prior to decompression
> > > - * can be avoided.
> > > - */
> > > - if (mem_size > SZ_64M)
> > > - data->os_address = mem_start + SZ_32M;
> > > - else
> > > - data->os_address = mem_start + SZ_8M;
> > > -
> > > - load_address = data->os_address;
> > > - if (bootm_verbose(data))
> > > - printf("no os load address, defaulting to 0x%08lx\n",
> > > - load_address);
> > > - }
> > > -
> > > fd = open(data->os_file, O_RDONLY);
> > > if (fd < 0) {
> > > perror("open");
> > > @@ -292,6 +275,20 @@ static int do_bootz_linux(struct image_data *data)
> > > if (swap)
> > > end = swab32(end);
> > >
> > > + if (load_address == UIMAGE_INVALID_ADDRESS) {
> > > + /*
> > > + * Just use a conservative default of 4 times the size of the
> > > + * compressed image, to avoid the need for the kernel to reocate itself
> > s/reocate/relocate/
> >
> Thanks, will fix this.
>
> > > + * before decompression.
> > > + */
> > > + data->os_address = mem_start + PAGE_ALIGN(end * 4);
> > I'm not sure if that really matters, but end isn't necessarily[1] holding
> > the size of the compressed image. Even if it doesn't matter, using
> >
> > + data->os_address = mem_start + PAGE_ALIGN((end - start) * 4);
> >
> > is more clear here.
> >
> Right, I've also noticed this. But this error is is spread in a few more
> places, so I'll cook another patch for this.
>
> Regards,
> Lucas
>
Thank you for your suggestions.
If you don't mind, I'll wait for another patch and try booting a zImage (with
and without the upcoming patch).

Kind regards,
 Rolf

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