From mboxrd@z Thu Jan  1 00:00:00 1970
From: santosh.shilimkar@ti.com (Santosh Shilimkar)
Date: Sun, 22 May 2011 16:50:23 +0530
Subject: [RFC PATCH 2/2] omap: switch to ioremap function pointer
In-Reply-To: <201105221154.28211.arnd@arndb.de>
References: <1306055080-30420-1-git-send-email-plagnioj@jcrosoft.com>	<1306055080-30420-2-git-send-email-plagnioj@jcrosoft.com>
	<201105221154.28211.arnd@arndb.de>
Message-ID: <4DD8F177.9020809@ti.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On 5/22/2011 3:24 PM, Arnd Bergmann wrote:
> On Sunday 22 May 2011 11:04:40 Jean-Christophe PLAGNIOL-VILLARD wrote:
>>
>> --- a/arch/arm/plat-omap/io.c
>> +++ b/arch/arm/plat-omap/io.c
>> @@ -23,6 +23,12 @@
>>   #define BETWEEN(p,st,sz)       ((p)>= (st)&&  (p)<  ((st) + (sz)))
>>   #define XLATE(p,pst,vst)       ((void __iomem *)((p) - (pst) + (vst)))
>>
>> +void __init omap_set_ioremap(void)
>> +{
>> +       arch_ioremap = omap_ioremap;
>> +       arch_iounmap = omap_iounmap;
>> +}
>> +
>>   /*
>>    * Intercept ioremap() requests for addresses in our fixed mapping regions.
>
> The only thing that the ioremap functions for omap do as a special case
> is to handle the fixed mappings. Maybe a better approach would be to
> make handling this in omap (and others) unnecessary, using one of
> two approaches:
>
> * Remove all fixed mappings that are also ioremapped, and rely on every
>    user calling ioremap correctly. I don't see why we would want to allow
>    both methods anyway.
>
What do you mean by "Remove all fixed mappings that are also
ioremapped" ?
Why will you ioremap() it again if the fixed mapping is already
registered through iotable_init()

> * Handle the fixed mappings in the generic ioremap code. They all go through
>    create_mapping(), so we can save a list to walk there.
>
This seems good approach in case we are ok to create and save the IO
list. This will also help to avoid un-necessary dual mappings which
can happen today if the mapping is outside the fixed mapping.

Regards
Santosh