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/*
* OpenRISC ioremap.c
*
* Linux architectural port borrowing liberally from similar works of
* others. All original copyrights apply as per the original source
* declaration.
*
* Modifications for the OpenRISC architecture:
* Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
* Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/vmalloc.h>
#include <linux/io.h>
#include <asm/pgalloc.h>
#include <asm/kmap_types.h>
#include <asm/fixmap.h>
#include <asm/bug.h>
#include <asm/pgtable.h>
#include <linux/sched.h>
#include <asm/tlbflush.h>
extern int mem_init_done;
static unsigned int fixmaps_used __initdata;
/*
* Remap an arbitrary physical address space into the kernel virtual
* address space. Needed when the kernel wants to access high addresses
* directly.
*
* NOTE! We need to allow non-page-aligned mappings too: we will obviously
* have to convert them into an offset in a page-aligned mapping, but the
* caller shouldn't need to know that small detail.
*/
void __iomem *__ref
__ioremap(phys_addr_t addr, unsigned long size, pgprot_t prot)
{
phys_addr_t p;
unsigned long v;
unsigned long offset, last_addr;
struct vm_struct *area = NULL;
/* Don't allow wraparound or zero size */
last_addr = addr + size - 1;
if (!size || last_addr < addr)
return NULL;
/*
* Mappings have to be page-aligned
*/
offset = addr & ~PAGE_MASK;
p = addr & PAGE_MASK;
size = PAGE_ALIGN(last_addr + 1) - p;
if (likely(mem_init_done)) {
area = get_vm_area(size, VM_IOREMAP);
if (!area)
return NULL;
v = (unsigned long)area->addr;
} else {
if ((fixmaps_used + (size >> PAGE_SHIFT)) > FIX_N_IOREMAPS)
return NULL;
v = fix_to_virt(FIX_IOREMAP_BEGIN + fixmaps_used);
fixmaps_used += (size >> PAGE_SHIFT);
}
if (ioremap_page_range(v, v + size, p, prot)) {
if (likely(mem_init_done))
vfree(area->addr);
else
fixmaps_used -= (size >> PAGE_SHIFT);
return NULL;
}
return (void __iomem *)(offset + (char *)v);
}
void iounmap(void *addr)
{
/* If the page is from the fixmap pool then we just clear out
* the fixmap mapping.
*/
if (unlikely((unsigned long)addr > FIXADDR_START)) {
/* This is a bit broken... we don't really know
* how big the area is so it's difficult to know
* how many fixed pages to invalidate...
* just flush tlb and hope for the best...
* consider this a FIXME
*
* Really we should be clearing out one or more page
* table entries for these virtual addresses so that
* future references cause a page fault... for now, we
* rely on two things:
* i) this code never gets called on known boards
* ii) invalid accesses to the freed areas aren't made
*/
flush_tlb_all();
return;
}
return vfree((void *)(PAGE_MASK & (unsigned long)addr));
}
/**
* OK, this one's a bit tricky... ioremap can get called before memory is
* initialized (early serial console does this) and will want to alloc a page
* for its mapping. No userspace pages will ever get allocated before memory
* is initialized so this applies only to kernel pages. In the event that
* this is called before memory is initialized we allocate the page using
* the memblock infrastructure.
*/
pte_t __ref *pte_alloc_one_kernel(struct mm_struct *mm,
unsigned long address)
{
pte_t *pte;
if (likely(mem_init_done)) {
pte = (pte_t *) __get_free_page(GFP_KERNEL);
} else {
pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
#if 0
/* FIXME: use memblock... */
pte = (pte_t *) __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE));
#endif
}
if (pte)
clear_page(pte);
return pte;
}
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