sh: reworked dynamic PMB mapping.

This implements a fairly significant overhaul of the dynamic PMB mapping
code. The primary change here is that the PMB gets its own VMA that
follows the uncached mapping and we attempt to be a bit more intelligent
with dynamic sizing, multi-entry mapping, and so forth.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 22 insertions, 48 deletions

diff --git a/arch/sh/mm/ioremap.c b/arch/sh/mm/ioremap.c
index c68d2d7d00a9..1ab2385ecefe 100644
--- a/arch/sh/mm/ioremap.c
+++ b/arch/sh/mm/ioremap.c
@@ -34,11 +34,12 @@
  * caller shouldn't need to know that small detail.
  */
 void __iomem * __init_refok
-__ioremap_caller(unsigned long phys_addr, unsigned long size,
+__ioremap_caller(phys_addr_t phys_addr, unsigned long size,
                  pgprot_t pgprot, void *caller)
 {
         struct vm_struct *area;
         unsigned long offset, last_addr, addr, orig_addr;
+        void __iomem *mapped;
 
         /* Don't allow wraparound or zero size */
         last_addr = phys_addr + size - 1;
@@ -46,6 +47,20 @@ __ioremap_caller(unsigned long phys_addr, unsigned long size,
                 return NULL;
 
         /*
+         * If we can't yet use the regular approach, go the fixmap route.
+         */
+        if (!mem_init_done)
+                return ioremap_fixed(phys_addr, size, pgprot);
+
+        /*
+         * First try to remap through the PMB.
+         * PMB entries are all pre-faulted.
+         */
+        mapped = pmb_remap_caller(phys_addr, size, pgprot, caller);
+        if (mapped && !IS_ERR(mapped))
+                return mapped;
+
+        /*
          * Mappings have to be page-aligned
          */
         offset = phys_addr & ~PAGE_MASK;
@@ -53,12 +68,6 @@ __ioremap_caller(unsigned long phys_addr, unsigned long size,
         size = PAGE_ALIGN(last_addr+1) - phys_addr;
 
         /*
-         * If we can't yet use the regular approach, go the fixmap route.
-         */
-        if (!mem_init_done)
-                return ioremap_fixed(phys_addr, offset, size, pgprot);
-
-        /*
          * Ok, go for it..
          */
         area = get_vm_area_caller(size, VM_IOREMAP, caller);
@@ -67,33 +76,10 @@ __ioremap_caller(unsigned long phys_addr, unsigned long size,
         area->phys_addr = phys_addr;
         orig_addr = addr = (unsigned long)area->addr;
 
-#ifdef CONFIG_PMB
-        /*
-         * First try to remap through the PMB once a valid VMA has been
-         * established. Smaller allocations (or the rest of the size
-         * remaining after a PMB mapping due to the size not being
-         * perfectly aligned on a PMB size boundary) are then mapped
-         * through the UTLB using conventional page tables.
-         *
-         * PMB entries are all pre-faulted.
-         */
-        if (unlikely(phys_addr >= P1SEG)) {
-                unsigned long mapped;
-
-                mapped = pmb_remap(addr, phys_addr, size, pgprot);
-                if (likely(mapped)) {
-                        addr            += mapped;
-                        phys_addr       += mapped;
-                        size            -= mapped;
-                }
+        if (ioremap_page_range(addr, addr + size, phys_addr, pgprot)) {
+                vunmap((void *)orig_addr);
+                return NULL;
         }
-#endif
-
-        if (likely(size))
-                if (ioremap_page_range(addr, addr + size, phys_addr, pgprot)) {
-                        vunmap((void *)orig_addr);
-                        return NULL;
-                }
 
         return (void __iomem *)(offset + (char *)orig_addr);
 }
@@ -133,23 +119,11 @@ void __iounmap(void __iomem *addr)
         if (iounmap_fixed(addr) == 0)
                 return;
 
-#ifdef CONFIG_PMB
         /*
-         * Purge any PMB entries that may have been established for this
-         * mapping, then proceed with conventional VMA teardown.
-         *
-         * XXX: Note that due to the way that remove_vm_area() does
-         * matching of the resultant VMA, we aren't able to fast-forward
-         * the address past the PMB space until the end of the VMA where
-         * the page tables reside. As such, unmap_vm_area() will be
-         * forced to linearly scan over the area until it finds the page
-         * tables where PTEs that need to be unmapped actually reside,
-         * which is far from optimal. Perhaps we need to use a separate
-         * VMA for the PMB mappings?
-         *                                      -- PFM.
+         * If the PMB handled it, there's nothing else to do.
          */
-        pmb_unmap(vaddr);
-#endif
+        if (pmb_unmap(addr) == 0)
+                return;
 
         p = remove_vm_area((void *)(vaddr & PAGE_MASK));
         if (!p) {