[ARM] 3705/1: add supersection support to ioremap()

Patch from Lennert Buytenhek

Analogous to the previous patch that allows ioremap() to use section
mappings, this patch allows ioremap() to use supersection mappings.
Original patch by Deepak Saxena.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
index 6aa13d59c85872d650dcd19d00e965c23eb9c748..7eac87f05180682ea45f3db06c0bdfe59e7739f1 100644 (file)
--- a/arch/arm/mm/ioremap.c
+++ b/arch/arm/mm/ioremap.c
@@ -33,8 +33,8 @@
 #include <asm/sizes.h>
 
 /*
- * Used by ioremap() and iounmap() code to mark section-mapped I/O regions
- * in vm_struct->flags field.
+ * Used by ioremap() and iounmap() code to mark (super)section-mapped
+ * I/O regions in vm_struct->flags field.
  */
 #define VM_ARM_SECTION_MAPPING 0x80000000
 
@@ -233,6 +233,54 @@ remap_area_sections(unsigned long virt, unsigned long pfn,
 
        return 0;
 }
+
+static int
+remap_area_supersections(unsigned long virt, unsigned long pfn,
+                        unsigned long size, unsigned long flags)
+{
+       unsigned long prot, addr = virt, end = virt + size;
+       pgd_t *pgd;
+
+       /*
+        * Remove and free any PTE-based mapping, and
+        * sync the current kernel mapping.
+        */
+       unmap_area_sections(virt, size);
+
+       prot = PMD_TYPE_SECT | PMD_SECT_SUPER | PMD_SECT_AP_WRITE |
+                       PMD_DOMAIN(DOMAIN_IO) |
+                       (flags & (L_PTE_CACHEABLE | L_PTE_BUFFERABLE));
+
+       /*
+        * ARMv6 and above need XN set to prevent speculative prefetches
+        * hitting IO.
+        */
+       if (cpu_architecture() >= CPU_ARCH_ARMv6)
+               prot |= PMD_SECT_XN;
+
+       pgd = pgd_offset_k(virt);
+       do {
+               unsigned long super_pmd_val, i;
+
+               super_pmd_val = __pfn_to_phys(pfn) | prot;
+               super_pmd_val |= ((pfn >> (32 - PAGE_SHIFT)) & 0xf) << 20;
+
+               for (i = 0; i < 8; i++) {
+                       pmd_t *pmd = pmd_offset(pgd, addr);
+
+                       pmd[0] = __pmd(super_pmd_val);
+                       pmd[1] = __pmd(super_pmd_val);
+                       flush_pmd_entry(pmd);
+
+                       addr += PGDIR_SIZE;
+                       pgd++;
+               }
+
+               pfn += SUPERSECTION_SIZE >> PAGE_SHIFT;
+       } while (addr < end);
+
+       return 0;
+}
 #endif
 
 
@@ -255,6 +303,13 @@ __ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
        int err;
        unsigned long addr;
        struct vm_struct * area;
+       unsigned int cr = get_cr();
+
+       /*
+        * High mappings must be supersection aligned
+        */
+       if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SUPERSECTION_MASK))
+               return NULL;
 
        area = get_vm_area(size, VM_IOREMAP);
        if (!area)
@@ -262,7 +317,12 @@ __ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
        addr = (unsigned long)area->addr;
 
 #ifndef CONFIG_SMP
-       if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) {
+       if ((((cpu_architecture() >= CPU_ARCH_ARMv6) && (cr & CR_XP)) ||
+              cpu_is_xsc3()) &&
+              !((__pfn_to_phys(pfn) | size | addr) & ~SUPERSECTION_MASK)) {
+               area->flags |= VM_ARM_SECTION_MAPPING;
+               err = remap_area_supersections(addr, pfn, size, flags);
+       } else if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) {
                area->flags |= VM_ARM_SECTION_MAPPING;
                err = remap_area_sections(addr, pfn, size, flags);
        } else

diff --git a/include/asm-arm/memory.h b/include/asm-arm/memory.h
index 176a4fb04989a63aa461fe624cbe902d8892ca73..91d536c215d79fc700b5c79f0dfb185bc6003eba 100644 (file)
--- a/include/asm-arm/memory.h
+++ b/include/asm-arm/memory.h
@@ -69,9 +69,9 @@
 #define XIP_VIRT_ADDR(physaddr)  (MODULE_START + ((physaddr) & 0x000fffff))
 
 /*
- * Allow 2MB-aligned ioremap pages
+ * Allow 16MB-aligned ioremap pages
  */
-#define IOREMAP_MAX_ORDER      21
+#define IOREMAP_MAX_ORDER      24
 
 #else /* CONFIG_MMU */