From 56d936607408d71c4141b2ed501410b072f1e211 Mon Sep 17 00:00:00 2001
From: Joerg Roedel <joerg.roedel@amd.com>
Date: Wed, 15 Oct 2008 22:02:10 -0700
Subject: introduce generic iommu_num_pages function

This patch introduces the generic iommu_num_pages function. It can be used by
a given memory area.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Muli Ben-Yehuda <muli@il.ibm.com>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 lib/iommu-helper.c | 9 +++++++++
 1 file changed, 9 insertions(+)

(limited to 'lib')

diff --git a/lib/iommu-helper.c b/lib/iommu-helper.c
index 5d90074dca7..75dbda03f4f 100644
--- a/lib/iommu-helper.c
+++ b/lib/iommu-helper.c
@@ -79,3 +79,12 @@ void iommu_area_free(unsigned long *map, unsigned long start, unsigned int nr)
 	}
 }
 EXPORT_SYMBOL(iommu_area_free);
+
+unsigned long iommu_num_pages(unsigned long addr, unsigned long len,
+			      unsigned long io_page_size)
+{
+	unsigned long size = (addr & (io_page_size - 1)) + len;
+
+	return DIV_ROUND_UP(size, io_page_size);
+}
+EXPORT_SYMBOL(iommu_num_pages);
-- 
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