From mboxrd@z Thu Jan  1 00:00:00 1970
From: davem@davemloft.net (David Miller)
Date: Tue, 09 Mar 2010 01:29:35 -0800 (PST)
Subject: DMA using data buffer vmapped in kernel space
In-Reply-To: <20100309091403.GB5691@n2100.arm.linux.org.uk>
References: <20100306193127.GA13262@n2100.arm.linux.org.uk>
	<10d816431003082345j5438d8cdi8ad72c4fa296b684@mail.gmail.com>
	<20100309091403.GB5691@n2100.arm.linux.org.uk>
Message-ID: <20100309.012935.98310472.davem@davemloft.net>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

From: Russell King - ARM Linux <linux@arm.linux.org.uk>
Date: Tue, 9 Mar 2010 09:14:03 +0000

> What you could do is prepare a patch to allow the firmware support to
> export a scatterlist via the struct firmware, and then use that with
> dma_map_sg().  Let's hope that the SPI interfaces support scatterlists.

It's so common to want a scatterlist from a vmalloc/vmap area
that a generic common helper is probably the best.

Just iterate over the vmalloc/vmap area using vmalloc_to_page()
to fill in the SG entries.