[PATCH] Generic ioremap_page_range: implementation

This patch adds a generic implementation of ioremap_page_range() in
lib/ioremap.c based on the i386 implementation. It differs from the
i386 version in the following ways:

  * The PTE flags are passed as a pgprot_t argument and must be
    determined up front by the arch-specific code. No additional
    PTE flags are added.
  * Uses set_pte_at() instead of set_pte()

[bunk@stusta.de: warning fix]
]dhowells@redhat.com: nommu build fix]
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Andi Kleen <ak@suse.de>
Cc: <linux-m32r@ml.linux-m32r.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@parisc-linux.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 95 insertions, 0 deletions

diff --git a/lib/Makefile b/lib/Makefile
index 402762fead70..ddf3e676e1f4 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -7,6 +7,7 @@ lib-y := errno.o ctype.o string.o vsprintf.o cmdline.o \
          idr.o div64.o int_sqrt.o bitmap.o extable.o prio_tree.o \
          sha1.o
 
+lib-$(CONFIG_MMU) += ioremap.o
 lib-$(CONFIG_SMP) += cpumask.o
 
 lib-y   += kobject.o kref.o kobject_uevent.o klist.o
diff --git a/lib/ioremap.c b/lib/ioremap.c
new file mode 100644
index 000000000000..29c810ec9813
--- /dev/null
+++ b/lib/ioremap.c
@@ -0,0 +1,94 @@
+/*
+ * Re-map IO memory to kernel address space so that we can access it.
+ * This is needed for high PCI addresses that aren't mapped in the
+ * 640k-1MB IO memory area on PC's
+ *
+ * (C) Copyright 1995 1996 Linus Torvalds
+ */
+#include <linux/io.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+
+#include <asm/cacheflush.h>
+#include <asm/pgtable.h>
+
+static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
+                unsigned long end, unsigned long phys_addr, pgprot_t prot)
+{
+        pte_t *pte;
+        unsigned long pfn;
+
+        pfn = phys_addr >> PAGE_SHIFT;
+        pte = pte_alloc_kernel(pmd, addr);
+        if (!pte)
+                return -ENOMEM;
+        do {
+                BUG_ON(!pte_none(*pte));
+                set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
+                pfn++;
+        } while (pte++, addr += PAGE_SIZE, addr != end);
+        return 0;
+}
+
+static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
+                unsigned long end, unsigned long phys_addr, pgprot_t prot)
+{
+        pmd_t *pmd;
+        unsigned long next;
+
+        phys_addr -= addr;
+        pmd = pmd_alloc(&init_mm, pud, addr);
+        if (!pmd)
+                return -ENOMEM;
+        do {
+                next = pmd_addr_end(addr, end);
+                if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, prot))
+                        return -ENOMEM;
+        } while (pmd++, addr = next, addr != end);
+        return 0;
+}
+
+static inline int ioremap_pud_range(pgd_t *pgd, unsigned long addr,
+                unsigned long end, unsigned long phys_addr, pgprot_t prot)
+{
+        pud_t *pud;
+        unsigned long next;
+
+        phys_addr -= addr;
+        pud = pud_alloc(&init_mm, pgd, addr);
+        if (!pud)
+                return -ENOMEM;
+        do {
+                next = pud_addr_end(addr, end);
+                if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, prot))
+                        return -ENOMEM;
+        } while (pud++, addr = next, addr != end);
+        return 0;
+}
+
+int ioremap_page_range(unsigned long addr,
+                       unsigned long end, unsigned long phys_addr, pgprot_t prot)
+{
+        pgd_t *pgd;
+        unsigned long start;
+        unsigned long next;
+        int err;
+
+        BUG_ON(addr >= end);
+
+        flush_cache_all();
+
+        start = addr;
+        phys_addr -= addr;
+        pgd = pgd_offset_k(addr);
+        do {
+                next = pgd_addr_end(addr, end);
+                err = ioremap_pud_range(pgd, addr, next, phys_addr+addr, prot);
+                if (err)
+                        break;
+        } while (pgd++, addr = next, addr != end);
+
+        flush_tlb_all();
+
+        return err;
+}