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Commit dd02b67d authored by Anatolij Gustschin's avatar Anatolij Gustschin Committed by David Woodhouse
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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: default avatarAnatolij Gustschin <agust@denx.de>
Acked-by: default avatarMike Frysinger <vapier@gentoo.org>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 68640c2a

drivers/mtd/mtdchar.c

+27 −1
Original line number Diff line number Diff line
@@ -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;