From: Robert Jarzmik <robert.jarzmik@free.fr>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: barebox@lists.infradead.org
Subject: Re: ARM, MMU and IO space mapping
Date: Wed, 30 Nov 2011 23:06:13 +0100 [thread overview]
Message-ID: <87y5ux6zai.fsf@free.fr> (raw)
In-Reply-To: <20111129081501.GF27267@pengutronix.de> (Sascha Hauer's message of "Tue, 29 Nov 2011 09:15:01 +0100")
Sascha Hauer <s.hauer@pengutronix.de> writes:
> We use high vectors at 0xfff00000, so there won't be vectors at 0x0. the
> 0x0 mapping is only used to catch NULL pointer derefs.
> That said, being able to catch NULL pointers is a very good thing,
> especially when there is flash at 0x0 which might be accidently
> overwritten by some code acting on NULL pointers.
I don't know if it can be that easily overwritten, but catching NPE is always
good, it's true.
> With MMU we could just remap the flash in board code and pass the
> remapped address as resource to the cfi driver. While I think the
> cleanest solution would be to use ioremap in all drivers (and make
> this a no-op on most boards) I don't think it's worth it at the moment.
OK, remap in board, and input virtual mapping address into io ressource, simple
enough. OK, I'll try that.
That would require a function in arch/arm/cpu/mmu.c, to remap a physical address
range into a virtual one, wouldn't it ? Would you have a suggestion for the API
? As in map_io_section(u32 phys_addr, void *virt) ?
Cheers.
--
Robert
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next prev parent reply other threads:[~2011-11-30 22:06 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-24 11:24 ARM, MMU and IO space mapping Robert Jarzmik
2011-11-24 12:04 ` Sascha Hauer
2011-11-24 14:23 ` Marc Kleine-Budde
2011-11-24 20:09 ` Robert Jarzmik
2011-11-24 20:25 ` Marc Kleine-Budde
2011-11-25 0:01 ` Sascha Hauer
2011-11-27 22:30 ` Robert Jarzmik
2011-11-28 7:43 ` Sascha Hauer
2011-11-28 17:43 ` Robert Jarzmik
2011-11-29 8:15 ` Sascha Hauer
2011-11-30 22:06 ` Robert Jarzmik [this message]
2011-12-01 14:26 ` Sascha Hauer
2011-12-01 14:34 ` Marc Kleine-Budde
2011-12-11 13:01 ` Robert Jarzmik
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