Viewing file:  ioremap.c (3.31 KB) -rw-r--r--
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/*
* arch/s390/mm/ioremap.c
*
* S390 version
* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Hartmut Penner (hp@de.ibm.com)
*
* Derived from "arch/i386/mm/extable.c"
* (C) Copyright 1995 1996 Linus Torvalds
*
* 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
*/
#include <linux/vmalloc.h>
#include <asm/io.h>
#include <asm/pgalloc.h>
static inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned long size,
unsigned long phys_addr, unsigned long flags)
{
unsigned long end;
address &= ~PMD_MASK;
end = address + size;
if (end > PMD_SIZE)
end = PMD_SIZE;
if (address >= end)
BUG();
do {
if (!pte_none(*pte)) {
printk("remap_area_pte: page already exists\n");
BUG();
}
set_pte(pte, mk_pte_phys(phys_addr,
__pgprot(_PAGE_PRESENT | flags)));
address += PAGE_SIZE;
phys_addr += PAGE_SIZE;
pte++;
} while (address && (address < end));
}
static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,
unsigned long phys_addr, unsigned long flags)
{
unsigned long end;
address &= ~PGDIR_MASK;
end = address + size;
if (end > PGDIR_SIZE)
end = PGDIR_SIZE;
phys_addr -= address;
if (address >= end)
BUG();
do {
pte_t * pte = pte_alloc(&init_mm, pmd, address);
if (!pte)
return -ENOMEM;
remap_area_pte(pte, address, end - address, address + phys_addr, flags);
address = (address + PMD_SIZE) & PMD_MASK;
pmd++;
} while (address && (address < end));
return 0;
}
static int remap_area_pages(unsigned long address, unsigned long phys_addr,
unsigned long size, unsigned long flags)
{
int error;
pgd_t * dir;
unsigned long end = address + size;
phys_addr -= address;
dir = pgd_offset(&init_mm, address);
flush_cache_all();
if (address >= end)
BUG();
spin_lock(&init_mm.page_table_lock);
do {
pmd_t *pmd;
pmd = pmd_alloc(&init_mm, dir, address);
error = -ENOMEM;
if (!pmd)
break;
if (remap_area_pmd(pmd, address, end - address,
phys_addr + address, flags))
break;
error = 0;
address = (address + PGDIR_SIZE) & PGDIR_MASK;
dir++;
} while (address && (address < end));
spin_unlock(&init_mm.page_table_lock);
flush_tlb_all();
return 0;
}
/*
* Generic mapping function (not visible outside):
*/
/*
* Remap an arbitrary physical address space into the kernel virtual
* address space. Needed when the kernel wants to access high addresses
* directly.
*/
void * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
{
void * addr;
struct vm_struct * area;
if (phys_addr < virt_to_phys(high_memory))
return phys_to_virt(phys_addr);
if (phys_addr & ~PAGE_MASK)
return NULL;
size = PAGE_ALIGN(size);
if (!size || size > phys_addr + size)
return NULL;
area = get_vm_area(size, VM_IOREMAP);
if (!area)
return NULL;
addr = area->addr;
if (remap_area_pages(VMALLOC_VMADDR(addr), phys_addr, size, flags)) {
vfree(addr);
return NULL;
}
return addr;
}
void iounmap(void *addr)
{
if (addr > high_memory)
return vfree(addr);
}
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