linux-kernel - Re: [PATCH 4/6] regmap: add MMIO bus support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 4 Apr 2012 23:59:16 +0100
From:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
To:	Stephen Warren <swarren@...dotorg.org>
Cc:	linux-kernel@...r.kernel.org, Stephen Warren <swarren@...dia.com>
Subject: Re: [PATCH 4/6] regmap: add MMIO bus support

On Wed, Apr 04, 2012 at 03:48:31PM -0600, Stephen Warren wrote:
> From: Stephen Warren <swarren@...dia.com>
> 
> This is a basic memory-mapped-IO bus for regmap. It has the following
> features and limitations:

I applied these up to here but it was painful as patch 2 didn't apply
cleanly to -rc1 and git am couldn't find the blobs to use for
resolution.  Please check things worked out OK but I'm pretty sure they
did.

> * Registers themselves may be 8, 16, 32, or 64-bit. 64-bit is only
>   supported on 64-bit platforms.
> * Register offsets are limited to precisely 32-bit.
> * IO is performed using readl/writel, with no provision for using the
>   __raw_readl or readl_relaxed variants.

Also limited native endian register I/O.  It would have been much better
to fix this in the core - please consider producing followup patches to
push the code there, though it's far from essential.

> +static int regmap_mmio_gather_write(void *context,
> +				    const void *reg, size_t reg_size,
> +				    const void *val, size_t val_size)
> +{
> +	struct regmap_mmio_context *ctx = context;
> +	u32 offset;
> +
> +	if (reg_size != 4)
> +		return -EIO;

Given that you constrain on registration too this should be BUG_ON(),
we're seriously confused if we're specifying a different register size
here and -EIO is going to be a bit obscure.

Download attachment "signature.asc" of type "application/pgp-signature" (837 bytes)