linux-kernel - Re: [PATCH RFC 0/3] clk: CCF clock primitives + custom IO accessors

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:	Mon, 03 Mar 2014 11:38:49 -0800
From:	Stephen Boyd <sboyd@...eaurora.org>
To:	Sören Brinkmann <soren.brinkmann@...inx.com>
CC:	Gerhard Sittig <gsi@...x.de>,
	Mike Turquette <mturquette@...aro.org>,
	Michal Simek <michal.simek@...inx.com>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFC 0/3] clk: CCF clock primitives + custom IO accessors

On 03/03/14 11:13, Sören Brinkmann wrote:
> On Mon, 2014-03-03 at 08:07PM +0100, Gerhard Sittig wrote:
>> On Mon, Mar 03, 2014 at 09:35 -0800, Sören Brinkmann wrote:
>>> It would be nice if we could use the logic provided in the mux, div etc
>>> primitives independently of how the HW is accessed and what is
>>> necessary to shift and mask those register values around, right? I
>>> mean, at then end we want to model a clk-(div|mux) and not a
>>> clk-(div|mux) which has only a single, memory-mapped control register,
>>> that does not overlap with other things, ...
>> Did you lookup the ll_ops discussion in the thread that
>> originated from
>> http://article.gmane.org/gmane.linux.ports.arm.kernel/289895 and
>> did you see the outlined logic in
>> http://article.gmane.org/gmane.linux.ports.arm.omap/109233 and
>> http://article.gmane.org/gmane.linux.ports.arm.omap/109381 ?
>>
>> Support for regmap access instead of mere MMIO was one of the
>> things you could do with this approach.  You appear to be in the
>> situation where you need such an extension (or something similar,
>> but you really should look into the ll_ops thing).
> Thanks for those pointer, I have some reading to do. That seems to
> go into the right direction.  What is the status of those patches?
> Are they already merged or actively worked on?
>

Ugh. The ll_ops design is a simplified form of regmap. Why not just use
regmap? It seems like it would be possible to make a regmap per
clk_register_{basic_type}() call via regmap_init_mmio() while still
allowing those functions to take a void __iomem pointer. Then we could
remove clk_readl/clk_writel (after providing *_be variants of the
registration functions for PPC) and just use a regmap throughout the
basic clock type code. Finally we can introduce *_regmap() registration
functions that allow drivers to register basic clock types with regmaps.

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/