Re: [PATCH] soc/tegra: Register SoC device

[Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

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On Wed, Aug 23, 2017 at 10:49:36AM +0200, Arnd Bergmann wrote:
> On Tue, Aug 22, 2017 at 1:19 PM, Thierry Reding
> <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > On Tue, Aug 22, 2017 at 11:15:21AM +0100, Sudeep Holla wrote:
> >>
> >>
> >> On 17/08/17 15:42, Thierry Reding wrote:
> >> > From: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> >> >
> >> > Move this code from arch/arm/mach-tegra and make it common among 32-bit
> >> > and 64-bit Tegra SoCs. This is slightly complicated by the fact that on
> >> > 32-bit Tegra, the SoC device is used as the parent for all devices that
> >> > are instantiated from device tree.
> >> >
> >>
> >> This seem to be in linux-next and causing the below splat on my platform
> >> which is not Tegra :)
> >>
> >> WARNING: .... at drivers/soc/tegra/fuse/tegra-apbmisc.c:48
> >> tegra_get_chip_id+0x30/0x40
> >> Modules linked in:
> >> CPU: 2 PID: 1 Comm: swapper/0 Not tainted
> >> 4.13.0-rc6-next-20170822-00008-g52a8e57512ae #13
> >> task: ffff8009768a0000 task.stack: ffff000008038000
> >> PC is at tegra_get_chip_id+0x30/0x40
> >> LR is at tegra_get_chip_id+0x30/0x40
> >>  tegra_get_chip_id+0x30/0x40
> >>  tegra_soc_device_register+0x68/0xd0
> >>  tegra_init_soc+0x10/0x44
> >>  do_one_initcall+0x38/0x120
> >>  kernel_init_freeable+0x184/0x224
> >>  kernel_init+0x10/0x100
> >>  ret_from_fork+0x10/0x18
> >
> > Indeed. Does the below patch fix this?
> >
> > Thierry
> >
> > --- >8 ---
> > From 5706cacc2af5e4ef138d1cd9e1269ca4947a447f Mon Sep 17 00:00:00 2001
> > From: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> > Date: Tue, 22 Aug 2017 13:15:18 +0200
> > Subject: [PATCH] soc/tegra: Restrict SoC device registration to Tegra
> >
> > Commit 8a46828e623c ("soc/tegra: Register SoC device") added an initcall
> > to register the SoC device on Tegra. However, that code is unrestricted
> > and will run on all platforms, causing unwanted warnings.
> >
> > Fix this by first checking that we're running on hardware that supports
> > the fuses block that we use to provide SoC information.
> >
> > Fixes: 8a46828e623c ("soc/tegra: Register SoC device")
> > Signed-off-by: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> 
> I just found the same thing by inspection after running into
> 
> drivers/soc/tegra/fuse/fuse-tegra.c:360:0: error: expected ';' at end of input
> 
> Please fix that as well.

Done, though it's strange that I didn't see those errors. Are those
compiler errors or sparse errors?

I'll be sending out both patches right away.

> Lastly, I believe that tegra_init_fuse() has the same bug, it just doesn't lead
> to an Oops, just to a harmless warning message, but please add another
> check there, or combine the two checks in some form.

I don't think that's the case. The of_find_matching_node_and_match()
should catch all non-Tegra cases, and the backward-compatibility
fallback has an extra check on the SoC compatible. See the comment on
lines 295-298.

That code is fairly old and I haven't seen anybody bring up any errors
on non-Tegra platforms for that particular piece.

Thanks,
Thierry

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