>-----Original Message-----
>From: Mike Frysinger [mailto:[email protected]] 
>Sent: Friday, January 15, 2010 1:51 PM
>To: Song, Barry
>Cc: [email protected]; 
>[email protected]
>Subject: Re: [Linux-kernel-commits] [8168] trunk: mtd-physmap: 
>add support users can assign the probe type in board files
>
>On Thu, Jan 14, 2010 at 23:35, Song, Barry wrote:
>>>From: Mike Frysinger [mailto:[email protected]]
>>>On Thu, Jan 14, 2010 at 23:01, Song, Barry wrote:
>>>>From: Mike Frysinger [mailto:[email protected]]
>>>>>On Thu, Jan 14, 2010 at 22:24,  
><[email protected]> wrote:
>>>>>> Revision 8168 Author bhsong Date 2010-01-14 22:24:39 -0500
>>>>>>
>>>>>> Log Message
>>>>>>
>>>>>> mtd-physmap: add support users can assign the probe type in
>>>>>> board files
>>>>>>
>>>>>> Modified: trunk/drivers/mtd/maps/physmap.c (8167 => 8168)
>>>>>>
>>>>>>              probe_type = rom_probe_types;
>>>>>> -            for (; info->mtd[i] == NULL && *probe_type !=
>>>>>>NULL; probe_type++)
>>>>>> +            for (; info->mtd[i] == NULL && *probe_type !=
>>>>>>NULL; probe_type++) {
>>>>>> +                    if (info->probe_type != NULL)
>>>>>> +                            if (strcmp(info->probe_type,
>>>>>>*probe_type) != 0)
>>>>>> +                                    continue;
>>>>>>                      info->mtd[i] =
>>>>>>do_map_probe(*probe_type, &info->map[i]);
>>>>>> +            }
>>>>>
>>>>>this prevents people from putting a probe type into the board which
>>>>>isnt already listed in the physmap driver.  how about 
>doing the NULL
>>>>>check up front:
>>>>>       if (info->probe_type == NULL) {
>>>>>               for (; info->mtd[i] == NULL && *probe_type !=
>>>>>NULL; probe_type++)
>>>>>                       info->mtd[i] =
>>>>>do_map_probe(*probe_type, &info->map[i]);
>>>>>       } else
>>>>>               info->mtd[i] = do_map_probe(info->probe_type,
>>>>>&info->map[i]);
>>>>>
>>>>>this also gets rid of the redundant ptr/strcmp checks
>>>> This patch is fine to me. But if there is a new probe which is not
>>>> listed in physmap, it should be added to the list to 
>permit users to
>>>> detect.
>>>
>>>there's already probe types not listed there.  then again, what you
>>>want to do can already be accomplished with the plat-ram driver.  so
>>>why not use that instead.
>>
>> I don't think ram driver is not a right choice for a real 
>flash.  Its write and erase is fake.
>
>i mean when we're doing a ROM kernel.  the plat-ram driver lets you
>specify a specific probe type (mtd-rom) which lets you disable
>write/erase funcs.  a flash doing kernel XIP shouldnt be allowed to
>write/erase any sector.
Even though plat-ram supports assigning probe, physmap needs this support too.

For xip kernel to suppot writable flash, how about one of the following two 
ways:
1. let user assign cfi (or other interfaces) in board files directly, and let 
cfi ignore the detection.
2. relocation detection codes into RAM?

>-mike
>
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