Re: firmwareload fails for cortex-m7 on imx8mp

[Stefano Manni <stefano.manni@gmail.com>]

Hello Ahmad,

I put it on here: https://we.tl/t-HrzdMMJXpU
because I didn't know if I can attach files in the mailing list.

Best,
Stefano


Il giorno ven 15 nov 2024 alle ore 15:49 Ahmad Fatoum

<a.fatoum@pengutronix.de> ha scritto:
>
> Hello Stefano,
>
> On 15.11.24 15:47, Stefano Manni wrote:
> > Hello Ahmad,
> >
> > patch [1] works fine when M7 firmware is compiled to run from ITCM. Thank you!
>
> Thanks for testing.
>
> > But when I use exactly the same firmware but compiled to run from DDR
> > (see [2]) I got:
> >
> > barebox@NXP i.MX8MPlus EVK board:/ firmwareload hello-ddr.elf
> > remoteproc0: powering up remoteproc-cm7.of
> > ERROR: remoteproc0: bad phdr da 0x80000000 mem 0x3de4
> > ERROR: remoteproc0: Failed to load program segments: -22
> >
> > Note that I can run it both from linux and u-boot.
> >
> > [1] https://lore.barebox.org/barebox/20241115135242.1251691-1-a.fatoum@pengutronix.de/
> > [2] https://docs.zephyrproject.org/latest/boards/nxp/imx8mp_evk/doc/index.html#programming-and-debugging-m7
>
> Can you send me the ELF file, so I can look at the headers myself?
>
> Cheers,
> Ahmad
>
> >
> > Il giorno ven 15 nov 2024 alle ore 15:02 Ahmad Fatoum
> > <a.fatoum@pengutronix.de> ha scritto:
> >>
> >> Hello Stefano,
> >>
> >> On 15.11.24 14:43, Stefano Manni wrote:
> >>> Dear all,
> >>>
> >>> I cannot run an ELF image on the M7 core on the imx8mp soc.
> >>> The ELF comes from zephyr and it runs as expected when I load it from linux,
> >>> but in barebox I encounter this error:
> >>>
> >>> barebox@NXP i.MX8MPlus EVK board:/ tftp zephyr.elf
> >>>         [################################################################]
> >>> barebox@NXP i.MX8MPlus EVK board:/ firmwareload zephyr.elf
> >>> remoteproc0: powering up remoteproc-cm7.of
> >>> DABT (current EL) exception (ESR 0x96000061) at 0x00000000007e0004
> >>
> >> https://esr.arm64.dev/#0x96000061 decodes this as
> >> "Abort caused by writing to memory" (Alignment fault) with valid FAR.
> >>
> >> FAR is the addresss listed here (0x00000000007e0004), which is indeed
> >> not divisible by 8.
> >>
> >>> [<ffd826f4>] (__arch_memcpy+0x48/0x13c) from [<ffd82a00>] (memcpy+0xc/0x14)
> >>
> >> The optimized memcpy used here expects misalignment not to trap.
> >>
> >>> As you can see the exception happens when rproc_elf_load_segments() tries to
> >>> memcpy a segment where the M7 expects it. The ELF has been compiled to run
> >>> from ITCM memory (0x007E0000-0x007FFFFF).
> >>>
> >>> Do you have any idea? Maybe may I have to put a reserved-memory for ITCM?
> >>
> >> I think I may have broken this when I changed barebox to map everything outside
> >> main memory as uncached.
> >>
> >> I did this, because we 1) don't want to risk the main CPU speculating into I/O
> >> memory and 2) don't want to have to use memory barriers for synchronization.
> >>
> >> The flipside is that drivers that access I/O memory must do this via
> >> readl/writel and friends or via memcpy_io/memset_io. This was already required
> >> before, but some drivers that didn't do this were lucky enough to fly under
> >> the radar. At least for remoteproc, this seems no longer the case.
> >>
> >> I just Cc'd you on a patch to fix this for remoteproc.
> >> Please let me know with a Tested-by if this resolves your issue.
> >>
> >> Cheers,
> >> Ahmad
> >>
> >>>
> >>> Thank you.
> >>>
> >>> Best,
> >>> Stefano
> >>>
> >>>
> >>
> >>
> >> --
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> >
>
>
> --
> Pengutronix e.K.                           |                             |
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