Patchwork [v3] mtdchar: fix mmap() for MTD RAM/ROM char devices

login
register
mail settings
Submitter Anatolij Gustschin
Date June 12, 2010, 7:35 p.m.
Message ID <1276371338-14253-1-git-send-email-agust@denx.de>
Download mbox | patch
Permalink /patch/55398/
State New
Headers show

Comments

Anatolij Gustschin - June 12, 2010, 7:35 p.m.
For no-mmu systems mmap() on RAM/ROM devices already works
but for systems with mmu it probably was not tested and
currently 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@denx.de>
---
Changes since patch v2:
 - improved commit message and patch description
 - rebased to apply cleanly on current mtd-2.6 tree

 drivers/mtd/mtdchar.c |   30 +++++++++++++++++++++++++++++-
 1 files changed, 29 insertions(+), 1 deletions(-)
Mike Frysinger - June 13, 2010, 1:31 a.m.
On Sat, Jun 12, 2010 at 15:35, Anatolij Gustschin wrote:
> For no-mmu systems mmap() on RAM/ROM devices already works
> but for systems with mmu it probably was not tested and
> currently doesn't work.

nope, never did

> +               if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
> +                       return -EINVAL;

i'm pretty sure this is inappropriate and doesnt belong here
-mike
Anatolij Gustschin - June 14, 2010, 9:22 a.m.
On Sat, 12 Jun 2010 21:31:11 -0400
Mike Frysinger <vapier.adi@gmail.com> wrote:

> On Sat, Jun 12, 2010 at 15:35, Anatolij Gustschin wrote:
> > For no-mmu systems mmap() on RAM/ROM devices already works
> > but for systems with mmu it probably was not tested and
> > currently doesn't work.
> 
> nope, never did

Do you mean it never worked on mmu systems?

> 
> > +               if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
> > +                       return -EINVAL;
> 
> i'm pretty sure this is inappropriate and doesnt belong here

Then I'll drop this in the next patch.

Thanks,
Anatolij
Mike Frysinger - June 14, 2010, 6:21 p.m.
On Mon, Jun 14, 2010 at 05:22, Anatolij Gustschin wrote:
> On Sat, 12 Jun 2010 21:31:11 -0400 Mike Frysinger wrote:
>> On Sat, Jun 12, 2010 at 15:35, Anatolij Gustschin wrote:
>> > For no-mmu systems mmap() on RAM/ROM devices already works
>> > but for systems with mmu it probably was not tested and
>> > currently doesn't work.
>>
>> nope, never did
>
> Do you mean it never worked on mmu systems?

it probably wasnt tested too heavily if at all
-mike

Patch

diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index 8b223c0..f3b848e 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>
@@ -941,9 +942,36 @@  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) {
+		if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
+			return -EINVAL;
+		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;