93 lines
2.6 KiB
C
93 lines
2.6 KiB
C
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/*
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* (C) Copyright 1995 1996 Linus Torvalds
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* (C) Copyright 2012 Regents of the University of California
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/export.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 <asm/pgtable.h>
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/*
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* Remap an arbitrary physical address space into the kernel virtual
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* address space. Needed when the kernel wants to access high addresses
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* directly.
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*
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* NOTE! We need to allow non-page-aligned mappings too: we will obviously
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* have to convert them into an offset in a page-aligned mapping, but the
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* caller shouldn't need to know that small detail.
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*/
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static void __iomem *__ioremap_caller(phys_addr_t addr, size_t size,
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pgprot_t prot, void *caller)
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{
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phys_addr_t last_addr;
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unsigned long offset, vaddr;
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struct vm_struct *area;
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/* Disallow wrap-around or zero size */
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last_addr = addr + size - 1;
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if (!size || last_addr < addr)
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return NULL;
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/* Page-align mappings */
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offset = addr & (~PAGE_MASK);
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addr -= offset;
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size = PAGE_ALIGN(size + offset);
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area = get_vm_area_caller(size, VM_IOREMAP, caller);
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if (!area)
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return NULL;
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vaddr = (unsigned long)area->addr;
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if (ioremap_page_range(vaddr, vaddr + size, addr, prot)) {
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free_vm_area(area);
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return NULL;
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}
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return (void __iomem *)(vaddr + offset);
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}
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/*
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* ioremap - map bus memory into CPU space
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* @offset: bus address of the memory
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* @size: size of the resource to map
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*
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* ioremap performs a platform specific sequence of operations to
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* make bus memory CPU accessible via the readb/readw/readl/writeb/
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* writew/writel functions and the other mmio helpers. The returned
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* address is not guaranteed to be usable directly as a virtual
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* address.
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*
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* Must be freed with iounmap.
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*/
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void __iomem *ioremap(phys_addr_t offset, unsigned long size)
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{
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return __ioremap_caller(offset, size, PAGE_KERNEL,
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__builtin_return_address(0));
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}
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EXPORT_SYMBOL(ioremap);
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/**
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* iounmap - Free a IO remapping
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* @addr: virtual address from ioremap_*
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*
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* Caller must ensure there is only one unmapping for the same pointer.
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*/
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void iounmap(volatile void __iomem *addr)
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{
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vunmap((void *)((unsigned long)addr & PAGE_MASK));
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}
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EXPORT_SYMBOL(iounmap);
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