mtd: mtdchar: fix mmap for MTD RAM/ROM char devices

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=dd02b67d5e9e7896891fa27eb5db65f55a290998
Commit:     dd02b67d5e9e7896891fa27eb5db65f55a290998
Parent:     68640c2a416849ba8e0a69577d4be51a458a045a
Author:     Anatolij Gustschin <agust at denx.de>
AuthorDate: Tue Jun 15 09:30:15 2010 +0200
Committer:  David Woodhouse <David.Woodhouse at intel.com>
CommitDate: Wed Aug 4 10:57:33 2010 +0100

    mtd: mtdchar: fix mmap for MTD RAM/ROM char devices
    
    For no-mmu systems mmap() on RAM/ROM devices already works
    but for systems with mmu it probably was not tested and
    doesn't work.
    
    This patch allows using mmap() on MTD RAM/ROM devices on systems
    with MMU. It has been tested on mpc5121e based platform with
    MR0A16A MRAM device attached over LocalBus.
    
    Signed-off-by: Anatolij Gustschin <agust at denx.de>
    Acked-by: Mike Frysinger <vapier at gentoo.org>
    Signed-off-by: David Woodhouse <David.Woodhouse at intel.com>
---
 drivers/mtd/mtdchar.c |   28 +++++++++++++++++++++++++++-
 1 files changed, 27 insertions(+), 1 deletions(-)

diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index a8e69dd..c27e65e 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -18,6 +18,7 @@
 #include <linux/mount.h>
 
 #include <linux/mtd/mtd.h>
+#include <linux/mtd/map.h>
 #include <linux/mtd/compatmac.h>
 
 #include <asm/uaccess.h>
@@ -955,9 +956,34 @@ static int mtd_mmap(struct file *file, struct vm_area_struct *vma)
 #ifdef CONFIG_MMU
 	struct mtd_file_info *mfi = file->private_data;
 	struct mtd_info *mtd = mfi->mtd;
+	struct map_info *map = mtd->priv;
+	unsigned long start;
+	unsigned long off;
+	u32 len;
+
+	if (mtd->type == MTD_RAM || mtd->type == MTD_ROM) {
+		off = vma->vm_pgoff << PAGE_SHIFT;
+		start = map->phys;
+		len = PAGE_ALIGN((start & ~PAGE_MASK) + map->size);
+		start &= PAGE_MASK;
+		if ((vma->vm_end - vma->vm_start + off) > len)
+			return -EINVAL;
+
+		off += start;
+		vma->vm_pgoff = off >> PAGE_SHIFT;
+		vma->vm_flags |= VM_IO | VM_RESERVED;
+
+#ifdef pgprot_noncached
+		if (file->f_flags & O_DSYNC || off >= __pa(high_memory))
+			vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+#endif
+		if (io_remap_pfn_range(vma, vma->vm_start, off >> PAGE_SHIFT,
+				       vma->vm_end - vma->vm_start,
+				       vma->vm_page_prot))
+			return -EAGAIN;
 
-	if (mtd->type == MTD_RAM || mtd->type == MTD_ROM)
 		return 0;
+	}
 	return -ENOSYS;
 #else
 	return vma->vm_flags & VM_SHARED ? 0 : -ENOSYS;