Patchwork mtdchar: allow mmap() on MTD RAM/ROM char devices

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Submitter Anatolij Gustschin
Date April 16, 2010, 3:41 p.m.
Message ID <1271432507-4280-1-git-send-email-agust@denx.de>
Download mbox | patch
Permalink /patch/50336/
State New
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Comments

Anatolij Gustschin - April 16, 2010, 3:41 p.m.
Signed-off-by: Anatolij Gustschin <agust@denx.de>
---
 drivers/mtd/mtdchar.c |   29 ++++++++++++++++++++++++++++-
 1 files changed, 28 insertions(+), 1 deletions(-)
Artem Bityutskiy - April 28, 2010, 1:25 p.m.
On Fri, 2010-04-16 at 17:41 +0200, Anatolij Gustschin wrote:
> Signed-off-by: Anatolij Gustschin <agust@denx.de>
> ---
>  drivers/mtd/mtdchar.c |   29 ++++++++++++++++++++++++++++-
>  1 files changed, 28 insertions(+), 1 deletions(-)
> 

Taken this to l2-mtd-2.6.git / dunno
Artem Bityutskiy - April 28, 2010, 1:31 p.m.
On Wed, 2010-04-28 at 16:25 +0300, Artem Bityutskiy wrote:
> On Fri, 2010-04-16 at 17:41 +0200, Anatolij Gustschin wrote:
> > Signed-off-by: Anatolij Gustschin <agust@denx.de>
> > ---
> >  drivers/mtd/mtdchar.c |   29 ++++++++++++++++++++++++++++-
> >  1 files changed, 28 insertions(+), 1 deletions(-)
> > 
> 
> Taken this to l2-mtd-2.6.git / dunno

Removed, because it breaks compilation on my x86_64:

[dedekind@sauron l2-mtd-2.6]\$ make -j8
  CHK     include/linux/version.h
  CHK     include/generated/utsrelease.h
  CALL    scripts/checksyscalls.sh
  CHK     include/generated/compile.h
  CC [M]  drivers/mtd/mtdchar.o
  CHK     include/linux/version.h
make[2]: `scripts/unifdef' is up to date.
  Building modules, stage 2.
Kernel: arch/x86/boot/bzImage is ready  (#3)
  MODPOST 1635 modules
ERROR: "phys_mem_access_prot" [drivers/mtd/mtdchar.ko] undefined!
WARNING: modpost: Found 11 section mismatch(es).
To see full details build your kernel with:
'make CONFIG_DEBUG_SECTION_MISMATCH=y'
make[1]: *** [__modpost] Error 1
make: *** [modules] Error 2
[dedekind@sauron l2-mtd-2.6]\$ git

Patch

diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index c355491..416f6eb 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -17,6 +17,7 @@ 
 #include <linux/compat.h>
 
 #include <linux/mtd/mtd.h>
+#include <linux/mtd/map.h>
 #include <linux/mtd/compatmac.h>
 
 #include <asm/uaccess.h>
@@ -925,9 +926,35 @@  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;
+		vma->vm_page_prot =
+			phys_mem_access_prot(file, off >> PAGE_SHIFT,
+					     vma->vm_end - vma->vm_start,
+					     vma->vm_page_prot);
+		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;