ioremap.c
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/*
* 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/vmalloc.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/io.h>
#include <linux/export.h>
#include <asm/cacheflush.h>
#include <asm/pgtable.h>
#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
static int __read_mostly ioremap_pud_capable;
static int __read_mostly ioremap_pmd_capable;
static int __read_mostly ioremap_huge_disabled;
static int __init set_nohugeiomap(char *str)
{
ioremap_huge_disabled = 1;
return 0;
}
early_param("nohugeiomap", set_nohugeiomap);
void __init ioremap_huge_init(void)
{
if (!ioremap_huge_disabled) {
if (arch_ioremap_pud_supported())
ioremap_pud_capable = 1;
if (arch_ioremap_pmd_supported())
ioremap_pmd_capable = 1;
}
}
static inline int ioremap_pud_enabled(void)
{
return ioremap_pud_capable;
}
static inline int ioremap_pmd_enabled(void)
{
return ioremap_pmd_capable;
}
#else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
static inline int ioremap_pud_enabled(void) { return 0; }
static inline int ioremap_pmd_enabled(void) { return 0; }
#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
{
pte_t *pte;
u64 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, phys_addr_t 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_pmd_enabled() &&
((next - addr) == PMD_SIZE) &&
IS_ALIGNED(phys_addr + addr, PMD_SIZE)) {
if (pmd_set_huge(pmd, phys_addr + addr, prot))
continue;
}
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, phys_addr_t 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_pud_enabled() &&
((next - addr) == PUD_SIZE) &&
IS_ALIGNED(phys_addr + addr, PUD_SIZE)) {
if (pud_set_huge(pud, phys_addr + addr, prot))
continue;
}
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, phys_addr_t phys_addr, pgprot_t prot)
{
pgd_t *pgd;
unsigned long start;
unsigned long next;
int err;
BUG_ON(addr >= end);
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_cache_vmap(start, end);
return err;
}
EXPORT_SYMBOL_GPL(ioremap_page_range);