Author: ian
Date: Sat Jan  4 21:38:41 2014
New Revision: 260288
URL: http://svnweb.freebsd.org/changeset/base/260288

Log:
  In pmap_mapdev(), first check whether a static mapping exists, and if so
  use it rather than allocating kva space and making another mapping.  In
  pmap_unmapdev(), don't unmap/free if the mapping is static.

Modified:
  head/sys/arm/arm/devmap.c

Modified: head/sys/arm/arm/devmap.c
==============================================================================
--- head/sys/arm/arm/devmap.c   Sat Jan  4 21:32:53 2014        (r260287)
+++ head/sys/arm/arm/devmap.c   Sat Jan  4 21:38:41 2014        (r260288)
@@ -207,13 +207,23 @@ arm_devmap_vtop(void * vpva, vm_size_t s
 
 /*
  * Map a set of physical memory pages into the kernel virtual address space.
- * Return a pointer to where it is mapped. This routine is intended to be used
- * for mapping device memory, NOT real memory.
+ * Return a pointer to where it is mapped.
+ *
+ * This uses a pre-established static mapping if one exists for the requested
+ * range, otherwise it allocates kva space and maps the physical pages into it.
+ *
+ * This routine is intended to be used for mapping device memory, NOT real
+ * memory; the mapping type is inherently PTE_DEVICE in pmap_kenter_device().
  */
 void *
 pmap_mapdev(vm_offset_t pa, vm_size_t size)
 {
        vm_offset_t va, tmpva, offset;
+       void * rva;
+
+       /* First look in the static mapping table. */
+       if ((rva = arm_devmap_ptov(pa, size)) != NULL)
+               return (rva);
        
        offset = pa & PAGE_MASK;
        pa = trunc_page(pa);
@@ -240,8 +250,13 @@ void
 pmap_unmapdev(vm_offset_t va, vm_size_t size)
 {
        vm_offset_t tmpva, offset;
-       vm_size_t origsize = size;
-       
+       vm_size_t origsize;
+
+       /* Nothing to do if we find the mapping in the static table. */
+       if (arm_devmap_vtop((void*)va, size) != DEVMAP_PADDR_NOTFOUND)
+               return;
+
+       origsize = size;
        offset = va & PAGE_MASK;
        va = trunc_page(va);
        size = round_page(size + offset);
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