Re: [PATCH v2 4/6] ARM: tegra: rework fuse.c

From: Stephen Warren
Date: Mon Jan 06 2014 - 15:50:52 EST

On 12/24/2013 06:32 AM, Peter De Schrijver wrote:
> Reduce fuse.c to the minimum functionality required for the early bootstages.
> Also export tegra_read_straps() for use by the fuse driver.

Since the fuse driver is tristate, it could be a module. Doesn't it
literally need to be EXPORT_SYMBOL'd, not simply not static?

I'm rather worried that this series isn't bisectable, since this patch
removes a bunch of code that's replaced by code in the fuse driver which
can't be built/linked at this point in the series. I'm also worried
about initialization ordering, since a lot of the fuse code could be a

> diff --git a/arch/arm/mach-tegra/fuse.c b/arch/arm/mach-tegra/fuse.c

> -/* Tegra20 only */
> #define FUSE_UID_LOW 0x108
> #define FUSE_UID_HIGH 0x10c

Why remove that comment but leave the two defines it applies to?

> #define TEGRA20_FUSE_SPARE_BIT 0x200

That define, and tegra_spare_fuse() which uses it, are no longer used
after patch 5/6, but aren't removed in patch 5/6. Perhaps it'd be better
to squash or re-order the two patches, so this dead code can be removed?

> -int tegra_sku_id;
> -int tegra_cpu_process_id;
> -int tegra_core_process_id;
> int tegra_chip_id;
> -int tegra_cpu_speedo_id; /* only exist in Tegra30 and later */
> -int tegra_soc_speedo_id;
> enum tegra_revision tegra_revision;

It's a bit odd to remove most of this, but leave a few parts hanging
around. Wouldn't it be better to the drivers/misc/fuse code to export
this, so that /all/ the fuse logic was there, rather than part of it
being left over in arch/arm/? We'll need to fix that up anyway when we
start using these globals on ARMv8, so may as well get it right now.
Also, I rather think that the new drivers/misc/fuse code shouldn't be a
module or driver, so that we can guarantee it's always there to provide
the globals and that they are initialized early enough...
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at