[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>

diff --git a/include/linux/io.h b/include/linux/io.h
index 420e2fd..aa3f5af 100644 (file)
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -19,8 +19,12 @@
 #define _LINUX_IO_H
 
 #include <asm/io.h>
+#include <asm/page.h>
 
 void __iowrite32_copy(void __iomem *to, const void *from, size_t count);
 void __iowrite64_copy(void __iomem *to, const void *from, size_t count);
 
+int ioremap_page_range(unsigned long addr, unsigned long end,
+                      unsigned long phys_addr, pgprot_t prot);
+
 #endif /* _LINUX_IO_H */

diff --git a/lib/Makefile b/lib/Makefile
index 402762f..ddf3e67 100644 (file)
--- 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 (file)
index 0000000..29c810e
--- /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;
+}