From: Arnd Bergmann <arnd@arndb•de>
To: linuxppc-embedded@ozlabs•org
Cc: Misbah khan <misbah_khan@engineer•com>
Subject: Re: how to allocate 9MB of memory in kernel ?
Date: Fri, 18 Jul 2008 17:39:10 +0200 [thread overview]
Message-ID: <200807181739.10268.arnd@arndb.de> (raw)
In-Reply-To: <18525063.post@talk.nabble.com>
On Friday 18 July 2008, Misbah khan wrote:
> Now my concern is How can i map SDRAM one to one to circular buffer of such
> a huge size ????
As I mentioned, use vmalloc to get the memory, and provide an mmap function
that uses remap_vmalloc_range to put it into the user address space.
> My idea is that i will ioreamp SDRAM and do memcpy_toio() when ever i am
> writing to the the circular buffer which is dma allocated and pages are set
> reserved . and read the frame from user space .
ioremap and memcpy_toio style accesses only make sense for stuff that is
*not* your main memory. Memory is alrady directly accessible in the kernel
after allocating with get_free_pages, kmalloc or vmalloc. No need to
play with __iomem pointers for this.
Arnd <><
next prev parent reply other threads:[~2008-07-18 18:31 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-17 7:26 how to allocate 9MB of memory in kernel ? Misbah khan
2008-07-17 7:51 ` Marco Stornelli
2008-07-17 8:34 ` Misbah khan
2008-07-17 9:04 ` Marco Stornelli
2008-07-17 7:56 ` Arnd Bergmann
2008-07-17 8:19 ` Misbah khan
2008-07-17 8:24 ` Arnd Bergmann
2008-07-18 4:44 ` Misbah khan
2008-07-18 6:50 ` Marco Stornelli
2008-07-18 8:48 ` Misbah khan
2008-07-18 14:57 ` Timur Tabi
2008-07-18 15:39 ` Arnd Bergmann [this message]
2008-07-22 5:23 ` Misbah khan
2008-07-22 6:43 ` Marco Stornelli
2008-07-22 9:31 ` Arnd Bergmann
2008-07-22 9:47 ` Marco Stornelli
2008-07-22 13:22 ` Misbah khan
2008-07-22 15:12 ` Arnd Bergmann
2008-07-23 7:30 ` Misbah khan
2008-07-23 12:47 ` Alessandro Rubini
2008-07-24 8:33 ` Misbah khan
2008-07-24 9:31 ` Arnd Bergmann
2008-07-25 8:43 ` Misbah khan
2008-07-25 8:50 ` Arnd Bergmann
2008-08-02 19:13 ` harihanv
2008-07-17 8:02 ` Sylvain Joyeau
2008-07-17 8:41 ` Misbah khan
[not found] <mailman.2280.1216290829.2883.linuxppc-embedded@ozlabs.org>
2008-07-17 20:15 ` Siva Prasad
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