90 lines
2.3 KiB
C
90 lines
2.3 KiB
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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* Needed for memory-mapped I/O devices mapped outside our normal DRAM
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* window (that is, all memory-mapped I/O devices).
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*
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* Copyright (C) 1995,1996 Linus Torvalds
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*
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* Meta port based on CRIS-port by Axis Communications AB
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*/
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#include <linux/vmalloc.h>
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#include <linux/io.h>
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#include <linux/export.h>
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#include <linux/slab.h>
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#include <linux/mm.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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void __iomem *__ioremap(unsigned long phys_addr, size_t size,
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unsigned long flags)
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{
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unsigned long addr;
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struct vm_struct *area;
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unsigned long offset, last_addr;
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pgprot_t prot;
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/* Don't allow wraparound or zero size */
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last_addr = phys_addr + size - 1;
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if (!size || last_addr < phys_addr)
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return NULL;
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/* Custom region addresses are accessible and uncached by default. */
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if (phys_addr >= LINSYSCUSTOM_BASE &&
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phys_addr < (LINSYSCUSTOM_BASE + LINSYSCUSTOM_LIMIT))
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return (__force void __iomem *) phys_addr;
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/*
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* Mappings have to be page-aligned
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*/
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offset = phys_addr & ~PAGE_MASK;
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phys_addr &= PAGE_MASK;
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size = PAGE_ALIGN(last_addr+1) - phys_addr;
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prot = __pgprot(_PAGE_PRESENT | _PAGE_WRITE | _PAGE_DIRTY |
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_PAGE_ACCESSED | _PAGE_KERNEL | _PAGE_CACHE_WIN0 |
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flags);
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/*
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* Ok, go for it..
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*/
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area = get_vm_area(size, VM_IOREMAP);
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if (!area)
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return NULL;
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area->phys_addr = phys_addr;
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addr = (unsigned long) area->addr;
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if (ioremap_page_range(addr, addr + size, phys_addr, prot)) {
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vunmap((void *) addr);
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return NULL;
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}
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return (__force void __iomem *) (offset + (char *)addr);
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}
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EXPORT_SYMBOL(__ioremap);
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void __iounmap(void __iomem *addr)
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{
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struct vm_struct *p;
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if ((__force unsigned long)addr >= LINSYSCUSTOM_BASE &&
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(__force unsigned long)addr < (LINSYSCUSTOM_BASE +
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LINSYSCUSTOM_LIMIT))
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return;
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p = remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr));
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if (unlikely(!p)) {
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pr_err("iounmap: bad address %p\n", addr);
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return;
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}
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kfree(p);
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}
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EXPORT_SYMBOL(__iounmap);
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