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From: Simon Falsig <simon@newtec.dk>
To: linux-mtd@lists.infradead.org
Subject: mmap support for m25p80 device
Date: Tue, 20 Oct 2015 16:31:20 +0200	[thread overview]
Message-ID: <9d83b70759c3d2507200432b4ff162be@mail.gmail.com> (raw)

Hi,

I'm currently working on a new custom board (with a TI AM3356 ARM-Cortex
A8
CPU), with a 32 kB Everspin MR25H256 MRAM chip, attached over SPI. It
works
fine using the m25p80 driver, but I was wondering how complex it would be
to
add the possibility of memory-mapping the device in userspace? - mainly to
make the interface consistent with the board that it is replacing, which
uses
a different, mmap-able, RAM chip.

I'm not very experienced in the deeper aspects of the kernel, but I've
been
poking around a bit in the mtd subsystem, and it seems as if the main
thing
that is missing, is a valid get_unmapped_area() function for the m25p80
driver, and then to change the mtdchar_mmap() function (in mtdchar.c) to
actually allow mmap'ing on MMU systems.

But - does it even make sense to create such a function for m25p80? - and
how would I start?

Any pointers and/or comments are appreciated!
Thanks and best regards,
Simon Falsig
simon@newtec.dk

             reply	other threads:[~2015-10-20 14:31 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-20 14:31 Simon Falsig [this message]
2015-11-18  2:15 ` mmap support for m25p80 device Brian Norris
2015-11-19 21:31   ` Brian Norris
2015-11-20  8:41     ` Philippe De Muyter
2015-11-21  0:12       ` Brian Norris
2015-11-20  4:08   ` Vignesh R

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