From: Sergei Shtylyov <sshtylyov@ru•mvista.com>
To: Segher Boessenkool <segher@kernel•crashing.org>
Cc: ppcdev <linuxppc-dev@ozlabs•org>,
linux-mtd@lists•infradead.org, Milton Miller <miltonm@bga•com>
Subject: Re: [PATCH] powerpc: Create "rom" (MTD) device prpmc2800
Date: Sun, 03 Jun 2007 22:03:02 +0400 [thread overview]
Message-ID: <46630256.8050909@ru.mvista.com> (raw)
In-Reply-To: <d067769912d2ed5c9e1b4770b77303dd@kernel.crashing.org>
Hello.
Segher Boessenkool wrote:
>>> If it's a flash, compatible should be the chip type, and maybe as a
>>> second entry, what type of flash protocol (amd, intel, cfi, ...) it's
>>> compatible.
>> As I've already (and repatedly) stated before,
> And you repeatedly got answers too, yet you choose
> to rehash this whole discussion again.
Not I have started it. And I have my reasons, too. :-)
>> this gets you *nothing* WRT
>> selecting the proper driver in the current Linux MTD subsystem.
> Which Linux driver to use is not something that should
> be (directly) communicated in a device tree -- even if
Bah... what's "name" and "compatible" properties are for then. Nobody's
talking about the direct match but making the task of selecting a proper
driver more complex by specifying the details that don't help (if not hinder)
the correct selection is certainly not a way to go.
> you take the position the device tree is a nice big
> configuration file for Linux, what if a new Linux flash
> subsystem shows up (or even simply a driver got renamed,
> etc.)
There is no direct match in *this* case (for an example of such, refer to
FSL "gianfar" nodes ;-).
> -- the device tree on your board doesn't necessarily
> change when your kernel version does.
Well, I'm not anticipating any changes either in this case...
>> What it
>> actually *needs* to know is flash mapping information,
> It needs to know what kind of flash it is, and how it
> is connected -- i.e., it needs to describe the hardware.
> How Linux then decides to use it is its own game, but
> at least the device tree puts all the information it
> could possibly need out there.
>> the CFI/JEDEC interface then can be deduced by probing
> Most of the time, sure. Not always.
That's the way the cookie crumbles in Linux MTD for now. It's *always*
detecting this by probing -- you only can say what [not] to probe.
>> -- so, this property ("ptobe-type"), although specified in
>> Documentation/powerpc/booting-without-of.txt, is optional.
> Who is talking about "probe-type"? We are talking about "compatible".
See my other mail where I've told why I don't consider your example of
this prop valid...
> Segher
WBR, Sergei
next prev parent reply other threads:[~2007-06-03 18:01 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-02 4:30 [PATCH] powerpc: Create "rom" (MTD) device prpmc2800 Milton Miller
2007-06-02 7:39 ` Benjamin Herrenschmidt
2007-06-03 16:10 ` Sergei Shtylyov
2007-06-03 17:36 ` Segher Boessenkool
2007-06-03 18:03 ` Sergei Shtylyov [this message]
2007-06-03 18:25 ` Segher Boessenkool
2007-06-03 18:36 ` Sergei Shtylyov
2007-06-03 18:46 ` Segher Boessenkool
2007-06-03 19:16 ` Sergei Shtylyov
2007-06-03 21:04 ` Benjamin Herrenschmidt
2007-06-04 12:34 ` Sergei Shtylyov
2007-06-04 14:37 ` Segher Boessenkool
2007-06-04 14:49 ` Sergei Shtylyov
2007-06-07 14:53 ` David Woodhouse
2007-06-07 15:49 ` Segher Boessenkool
2007-06-07 14:47 ` David Woodhouse
2007-06-07 15:32 ` Segher Boessenkool
2007-06-02 8:53 ` Segher Boessenkool
2007-06-03 16:22 ` Sergei Shtylyov
2007-06-03 17:40 ` Segher Boessenkool
2007-06-03 18:31 ` Sergei Shtylyov
2007-06-03 18:44 ` Segher Boessenkool
2007-06-03 19:13 ` Sergei Shtylyov
2007-06-03 19:56 ` Segher Boessenkool
2007-06-03 20:26 ` Sergei Shtylyov
2007-06-04 8:07 ` Segher Boessenkool
2007-06-04 13:34 ` Sergei Shtylyov
2007-06-07 15:00 ` David Woodhouse
2007-06-07 15:55 ` Segher Boessenkool
2007-06-07 16:05 ` David Woodhouse
2007-06-07 16:46 ` Segher Boessenkool
2007-06-12 4:44 ` David Gibson
2007-06-12 10:53 ` Segher Boessenkool
2007-06-13 3:16 ` David Gibson
2007-06-13 5:05 ` Segher Boessenkool
2007-06-13 6:11 ` David Gibson
2007-06-13 9:10 ` Segher Boessenkool
2007-06-15 4:12 ` David Gibson
2007-06-15 11:22 ` Segher Boessenkool
2007-06-15 4:14 ` David Gibson
2007-06-15 8:42 ` Segher Boessenkool
2007-06-15 8:47 ` David Woodhouse
2007-06-15 8:59 ` Segher Boessenkool
2007-06-03 21:12 ` Benjamin Herrenschmidt
2007-06-04 8:11 ` Segher Boessenkool
2007-06-04 13:16 ` Sergei Shtylyov
2007-06-04 12:41 ` Sergei Shtylyov
2007-06-04 14:49 ` Segher Boessenkool
2007-06-04 15:54 ` Sergei Shtylyov
2007-06-03 17:29 ` Sergei Shtylyov
2007-06-03 17:45 ` Segher Boessenkool
2007-06-03 18:18 ` Sergei Shtylyov
2007-06-03 18:43 ` Segher Boessenkool
2007-06-03 18:59 ` Sergei Shtylyov
2007-06-03 19:48 ` Segher Boessenkool
2007-06-03 20:10 ` Sergei Shtylyov
2007-06-04 8:02 ` Segher Boessenkool
2007-06-04 19:40 ` Mark A. Greer
-- strict thread matches above, loose matches on Subject: below --
2007-06-01 23:20 Mark A. Greer
2007-06-02 8:46 ` Segher Boessenkool
2007-06-04 20:56 ` Mark A. Greer
2007-06-05 20:35 ` Sergei Shtylyov
2007-06-05 21:11 ` Mark A. Greer
2007-06-06 12:41 ` Sergei Shtylyov
2007-06-07 15:08 ` David Woodhouse
2007-06-06 2:39 ` David Gibson
2007-06-07 13:30 ` Segher Boessenkool
2007-06-12 4:42 ` David Gibson
2007-06-12 10:50 ` Segher Boessenkool
2007-06-13 6:12 ` David Gibson
2007-06-13 9:13 ` Segher Boessenkool
2007-06-13 9:19 ` David Gibson
2007-06-13 9:37 ` Segher Boessenkool
2007-06-14 4:29 ` David Gibson
2007-06-14 8:00 ` Segher Boessenkool
2007-06-14 12:39 ` Sergei Shtylyov
2007-06-14 13:20 ` Segher Boessenkool
2007-06-14 12:48 ` Sergei Shtylyov
2007-06-14 13:18 ` Segher Boessenkool
2007-06-14 12:50 ` Sergei Shtylyov
2007-06-14 13:43 ` Segher Boessenkool
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