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

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

[Anatolij Gustschin]

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(-)

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;
-- 
1.7.0.4

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

[Mike Frysinger]

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

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

[Anatolij Gustschin]

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

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

[Mike Frysinger]

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 v4] mtdchar: fix mmap() for MTD RAM/ROM char devices

[Anatolij Gustschin]

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@denx.de>
---
Changes since v3:
 - remove vma->vm_pgoff check as suggested by Mike
 - update commit message

Changes since v2:
 - improved commit message and patch description
 - rebased to apply cleanly on current mtd-2.6 tree

 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 8b223c0..c3e5423 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 +942,34 @@ 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;
-- 
1.7.0.4

Re: [PATCH v4] mtdchar: fix mmap() for MTD RAM/ROM char devices

[Mike Frysinger]

On Tue, Jun 15, 2010 at 03:30, 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
> 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.

i dont really have a way of testing the MMU path, but this looks sane.
Acked-by: Mike Frysinger <vapier@gentoo.org>
-mike

Re: [PATCH v4] mtdchar: fix mmap() for MTD RAM/ROM char devices

[Artem Bityutskiy]

On Tue, 2010-06-15 at 09:30 +0200, 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
> 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>

Pushed to l2-mtd-2.6.git / dunno

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)