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Subject[PATCH 1/14] Generic ioremap_page_range: implementation
Date
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()

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
---
include/linux/io.h | 4 ++
lib/Makefile | 2 +
lib/ioremap.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 98 insertions(+), 1 deletions(-)

diff --git a/include/linux/io.h b/include/linux/io.h
index 420e2fd..aa3f5af 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -19,8 +19,12 @@ #ifndef _LINUX_IO_H
#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 be9719a..a4dcb07 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -5,7 +5,7 @@ #
lib-y := errno.o ctype.o string.o vsprintf.o cmdline.o \
bust_spinlocks.o rbtree.o radix-tree.o dump_stack.o \
idr.o div64.o int_sqrt.o bitmap.o extable.o prio_tree.o \
- sha1.o
+ sha1.o ioremap.o

lib-$(CONFIG_SMP) += cpumask.o

diff --git a/lib/ioremap.c b/lib/ioremap.c
new file mode 100644
index 0000000..6419101
--- /dev/null
+++ b/lib/ioremap.c
@@ -0,0 +1,93 @@
+/*
+ * 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 <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;
+}
--
1.4.0
-
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