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				|  |  | +/*
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				|  |  | + *  linux/arch/arm/mm/ioremap.c
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				|  |  | + *
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				|  |  | + * Re-map IO memory to kernel address space so that we can access it.
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				|  |  | + *
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				|  |  | + * (C) Copyright 1995 1996 Linus Torvalds
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				|  |  | + *
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				|  |  | + * Hacked for ARM by Phil Blundell <philb@gnu.org>
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				|  |  | + * Hacked to allow all architectures to build, and various cleanups
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				|  |  | + * by Russell King
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				|  |  | + *
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				|  |  | + * This allows a driver to remap an arbitrary region of bus memory into
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				|  |  | + * virtual space.  One should *only* use readl, writel, memcpy_toio and
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				|  |  | + * so on with such remapped areas.
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				|  |  | + *
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				|  |  | + * Because the ARM only has a 32-bit address space we can't address the
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				|  |  | + * whole of the (physical) PCI space at once.  PCI huge-mode addressing
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				|  |  | + * allows us to circumvent this restriction by splitting PCI space into
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				|  |  | + * two 2GB chunks and mapping only one at a time into processor memory.
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				|  |  | + * We use MMU protection domains to trap any attempt to access the bank
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				|  |  | + * that is not currently mapped.  (This isn't fully implemented yet.)
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				|  |  | + */
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				|  |  | +#include <linux/module.h>
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				|  |  | +#include <linux/errno.h>
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				|  |  | +#include <linux/mm.h>
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				|  |  | +#include <linux/vmalloc.h>
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				|  |  | +#include <linux/io.h>
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				|  |  | +#include <linux/sizes.h>
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				|  |  | +
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				|  |  | +#include <asm/cp15.h>
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				|  |  | +#include <asm/cputype.h>
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				|  |  | +#include <asm/cacheflush.h>
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				|  |  | +#include <asm/mmu_context.h>
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				|  |  | +#include <asm/pgalloc.h>
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				|  |  | +#include <asm/tlbflush.h>
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				|  |  | +#include <asm/system_info.h>
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				|  |  | +
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				|  |  | +#include <asm/mach/map.h>
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				|  |  | +#include <asm/mach/pci.h>
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				|  |  | +#include "mm.h"
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				|  |  | +
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				|  |  | +int ioremap_page(unsigned long virt, unsigned long phys,
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				|  |  | +		 const struct mem_type *mtype)
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				|  |  | +{
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				|  |  | +	return ioremap_page_range(virt, virt + PAGE_SIZE, phys,
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				|  |  | +				  __pgprot(mtype->prot_pte));
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				|  |  | +}
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				|  |  | +EXPORT_SYMBOL(ioremap_page);
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				|  |  | +
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				|  |  | +void __check_vmalloc_seq(struct mm_struct *mm)
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				|  |  | +{
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				|  |  | +	unsigned int seq;
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				|  |  | +
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				|  |  | +	do {
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				|  |  | +		seq = init_mm.context.vmalloc_seq;
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				|  |  | +		memcpy(pgd_offset(mm, VMALLOC_START),
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				|  |  | +		       pgd_offset_k(VMALLOC_START),
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				|  |  | +		       sizeof(pgd_t) * (pgd_index(VMALLOC_END) -
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				|  |  | +					pgd_index(VMALLOC_START)));
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				|  |  | +		mm->context.vmalloc_seq = seq;
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				|  |  | +	} while (seq != init_mm.context.vmalloc_seq);
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				|  |  | +}
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				|  |  | +
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				|  |  | +#if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
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				|  |  | +/*
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				|  |  | + * Section support is unsafe on SMP - If you iounmap and ioremap a region,
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				|  |  | + * the other CPUs will not see this change until their next context switch.
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				|  |  | + * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs
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				|  |  | + * which requires the new ioremap'd region to be referenced, the CPU will
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				|  |  | + * reference the _old_ region.
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				|  |  | + *
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				|  |  | + * Note that get_vm_area_caller() allocates a guard 4K page, so we need to
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				|  |  | + * mask the size back to 1MB aligned or we will overflow in the loop below.
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				|  |  | + */
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				|  |  | +static void unmap_area_sections(unsigned long virt, unsigned long size)
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				|  |  | +{
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				|  |  | +	unsigned long addr = virt, end = virt + (size & ~(SZ_1M - 1));
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				|  |  | +	pgd_t *pgd;
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				|  |  | +	pud_t *pud;
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				|  |  | +	pmd_t *pmdp;
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				|  |  | +
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				|  |  | +	flush_cache_vunmap(addr, end);
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				|  |  | +	pgd = pgd_offset_k(addr);
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				|  |  | +	pud = pud_offset(pgd, addr);
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				|  |  | +	pmdp = pmd_offset(pud, addr);
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				|  |  | +	do {
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				|  |  | +		pmd_t pmd = *pmdp;
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				|  |  | +
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				|  |  | +		if (!pmd_none(pmd)) {
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				|  |  | +			/*
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				|  |  | +			 * Clear the PMD from the page table, and
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				|  |  | +			 * increment the vmalloc sequence so others
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				|  |  | +			 * notice this change.
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				|  |  | +			 *
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				|  |  | +			 * Note: this is still racy on SMP machines.
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				|  |  | +			 */
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				|  |  | +			pmd_clear(pmdp);
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				|  |  | +			init_mm.context.vmalloc_seq++;
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				|  |  | +
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				|  |  | +			/*
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				|  |  | +			 * Free the page table, if there was one.
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				|  |  | +			 */
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				|  |  | +			if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
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				|  |  | +				pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
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				|  |  | +		}
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				|  |  | +
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				|  |  | +		addr += PMD_SIZE;
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				|  |  | +		pmdp += 2;
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				|  |  | +	} while (addr < end);
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				|  |  | +
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				|  |  | +	/*
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				|  |  | +	 * Ensure that the active_mm is up to date - we want to
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				|  |  | +	 * catch any use-after-iounmap cases.
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				|  |  | +	 */
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				|  |  | +	if (current->active_mm->context.vmalloc_seq != init_mm.context.vmalloc_seq)
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				|  |  | +		__check_vmalloc_seq(current->active_mm);
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				|  |  | +
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				|  |  | +	flush_tlb_kernel_range(virt, end);
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				|  |  | +}
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				|  |  | +
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				|  |  | +static int
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				|  |  | +remap_area_sections(unsigned long virt, unsigned long pfn,
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				|  |  | +		    size_t size, const struct mem_type *type)
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				|  |  | +{
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				|  |  | +	unsigned long addr = virt, end = virt + size;
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				|  |  | +	pgd_t *pgd;
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				|  |  | +	pud_t *pud;
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				|  |  | +	pmd_t *pmd;
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				|  |  | +
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				|  |  | +	/*
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				|  |  | +	 * Remove and free any PTE-based mapping, and
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				|  |  | +	 * sync the current kernel mapping.
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				|  |  | +	 */
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				|  |  | +	unmap_area_sections(virt, size);
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				|  |  | +
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				|  |  | +	pgd = pgd_offset_k(addr);
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				|  |  | +	pud = pud_offset(pgd, addr);
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				|  |  | +	pmd = pmd_offset(pud, addr);
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				|  |  | +	do {
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				|  |  | +		pmd[0] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
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				|  |  | +		pfn += SZ_1M >> PAGE_SHIFT;
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				|  |  | +		pmd[1] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
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				|  |  | +		pfn += SZ_1M >> PAGE_SHIFT;
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				|  |  | +		flush_pmd_entry(pmd);
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				|  |  | +
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				|  |  | +		addr += PMD_SIZE;
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				|  |  | +		pmd += 2;
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				|  |  | +	} while (addr < end);
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				|  |  | +
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				|  |  | +	return 0;
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				|  |  | +}
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				|  |  | +
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				|  |  | +static int
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				|  |  | +remap_area_supersections(unsigned long virt, unsigned long pfn,
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				|  |  | +			 size_t size, const struct mem_type *type)
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				|  |  | +{
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