src/patches/suse-2.6.27.31/patches.arch/ppc-pseries-bsr-4k.patch

   1 Subject: Unable to Use Small BSR register on Power LPAR
   2 From: Sonny Rao <sonnyrao@us.ibm.com>
   3 References: 443673 - LTC49749
   4
   5 Fix the BSR driver to allow small BSR devices on a 64k page kernel.
   6 Previously the driver would reject the mmap since the size was smaller
   7 than PAGESIZE. This patch adds a  check for this case and uses remap_4k_pfn().
   8
   9 Also, take out code to set vm_flags, as the remap_pfn functions will
  10 do this for us.
  11
  12 Signed-off-by: Sonny Rao <sonnyrao@us.ibm.com>
  13 Signed-off-by: Olaf Hering <olh@suse.de>
  14
  15 ---
  16  drivers/char/bsr.c |   20 ++++++++++++++------
  17  1 file changed, 14 insertions(+), 6 deletions(-)
  18
  19 --- a/drivers/char/bsr.c
  20 +++ b/drivers/char/bsr.c
  21 @@ -27,6 +27,7 @@
  22  #include <linux/cdev.h>
  23  #include <linux/list.h>
  24  #include <linux/mm.h>
  25 +#include <asm/pgtable.h>
  26  #include <asm/io.h>
  27
  28  /*
  29 @@ -115,15 +116,22 @@ static int bsr_mmap(struct file *filp, s
  30  {
  31         unsigned long size   = vma->vm_end - vma->vm_start;
  32         struct bsr_dev *dev = filp->private_data;
  33 +       int ret;
  34
  35 -       if (size > dev->bsr_len || (size & (PAGE_SIZE-1)))
  36 -               return -EINVAL;
  37 -
  38 -       vma->vm_flags |= (VM_IO | VM_DONTEXPAND);
  39         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
  40
  41 -       if (io_remap_pfn_range(vma, vma->vm_start, dev->bsr_addr >> PAGE_SHIFT,
  42 -                              size, vma->vm_page_prot))
  43 +       /* check for the case of a small BSR device and map one 4k page for it*/
  44 +       if (dev->bsr_len < PAGE_SIZE && size == PAGE_SIZE)
  45 +               ret = remap_4k_pfn(vma, vma->vm_start, dev->bsr_addr >> 12,
  46 +                                  vma->vm_page_prot);
  47 +       else if (size <= dev->bsr_len)
  48 +               ret = io_remap_pfn_range(vma, vma->vm_start,
  49 +                                        dev->bsr_addr >> PAGE_SHIFT,
  50 +                                        size, vma->vm_page_prot);
  51 +       else
  52 +               return -EINVAL;
  53 +
  54 +       if (ret)
  55                 return -EAGAIN;
  56
  57         return 0;