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Subject[patch 07/13] x86: PAT use reserve free memtype in pci_mmap_page_range
Add reserve_memtype and free_memtype wrapper for pci_mmap_page_range. Free
is called on unmap, but identity map continues to be mapped as per
pci_mmap_page_range request, until next request for the same region calls
ioremap_change_attr(), which will go through without conflict. This way of
mapping is identical to one used in ioremap/iounmap.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>

Index: linux-2.6-x86.git/arch/x86/pci/i386.c
===================================================================
--- linux-2.6-x86.git.orig/arch/x86/pci/i386.c 2008-03-18 02:16:05.000000000 -0700
+++ linux-2.6-x86.git/arch/x86/pci/i386.c 2008-03-18 03:29:39.000000000 -0700
@@ -30,6 +30,9 @@
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/errno.h>
+#include <linux/bootmem.h>
+
+#include <asm/pat.h>

#include "pci.h"

@@ -297,10 +300,34 @@
pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat);
}

+static void pci_unmap_page_range(struct vm_area_struct *vma)
+{
+ u64 addr = (u64)vma->vm_pgoff << PAGE_SHIFT;
+ free_memtype(addr, addr + vma->vm_end - vma->vm_start);
+}
+
+static void pci_track_mmap_page_range(struct vm_area_struct *vma)
+{
+ u64 addr = (u64)vma->vm_pgoff << PAGE_SHIFT;
+ unsigned long flags = pgprot_val(vma->vm_page_prot)
+ & _PAGE_CACHE_MASK;
+
+ reserve_memtype(addr, addr + vma->vm_end - vma->vm_start, flags, NULL);
+}
+
+static struct vm_operations_struct pci_mmap_ops = {
+ .open = pci_track_mmap_page_range,
+ .close = pci_unmap_page_range,
+};
+
int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
enum pci_mmap_state mmap_state, int write_combine)
{
unsigned long prot;
+ u64 addr = vma->vm_pgoff << PAGE_SHIFT;
+ unsigned long len = vma->vm_end - vma->vm_start;
+ unsigned long flags;
+ unsigned long new_flags;

/* I/O space cannot be accessed via normal processor loads and
* stores on this platform.
@@ -308,21 +335,46 @@
if (mmap_state == pci_mmap_io)
return -EINVAL;

- /* Leave vm_pgoff as-is, the PCI space address is the physical
- * address on this platform.
- */
prot = pgprot_val(vma->vm_page_prot);
- if (boot_cpu_data.x86 > 3)
- prot |= _PAGE_PCD | _PAGE_PWT;
+ if (pat_wc_enabled && write_combine)
+ prot |= _PAGE_CACHE_WC;
+ else if (boot_cpu_data.x86 > 3)
+ prot |= _PAGE_CACHE_UC;
+
vma->vm_page_prot = __pgprot(prot);

- /* Write-combine setting is ignored, it is changed via the mtrr
- * interfaces on this platform.
- */
+ flags = pgprot_val(vma->vm_page_prot) & _PAGE_CACHE_MASK;
+ if (reserve_memtype(addr, addr + len, flags, &new_flags)) {
+ /*
+ * Do not fallback to certain memory types with certain
+ * requested type:
+ * - request is uncached, return cannot be write-back
+ * - request is uncached, return cannot be write-combine
+ * - request is write-combine, return cannot be write-back
+ */
+ if ((flags == _PAGE_CACHE_UC &&
+ (new_flags == _PAGE_CACHE_WB ||
+ new_flags == _PAGE_CACHE_WC)) ||
+ (flags == _PAGE_CACHE_WC &&
+ new_flags == _PAGE_CACHE_WB)) {
+ free_memtype(addr, addr+len);
+ return -EINVAL;
+ }
+ flags = new_flags;
+ }
+
+ if (vma->vm_pgoff <= max_pfn_mapped &&
+ ioremap_change_attr((unsigned long)__va(addr), len, flags)) {
+ free_memtype(addr, addr + len);
+ return -EINVAL;
+ }
+
if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
vma->vm_end - vma->vm_start,
vma->vm_page_prot))
return -EAGAIN;

+ vma->vm_ops = &pci_mmap_ops;
+
return 0;
}
--


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