Re: firmwareload fails for cortex-m7 on imx8mp

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

Hello Ahmad,

patch [1] works fine when M7 firmware is compiled to run from ITCM. Thank you!

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

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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