| 1 | |
| 2 | * Re-map IO memory to kernel address space so that we can access it.
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| 3 | * This is needed for high PCI addresses that aren't mapped in the
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| 4 | * 640k-1MB IO memory area on PC's
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| 5 | *
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| 6 | * (C) Copyright 1995 1996 Linus Torvalds
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| 7 |
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| 8 | #include <linux/vmalloc.h>
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| 9 | #include <linux/mm.h>
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| 10 | #include <linux/sched.h>
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| 11 | #include <linux/io.h>
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| 12 | #include <asm/cacheflush.h>
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| 13 | #include <asm/pgtable.h>
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| 14 |
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| 15 | static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
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| 16 | unsigned long end, unsigned long phys_addr, pgprot_t prot)
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| 17 | {
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| 18 | pte_t *pte;
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| 19 | unsigned long pfn;
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| 20 |
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| 21 | pfn = phys_addr >> PAGE_SHIFT;
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| 22 | pte = pte_alloc_kernel(pmd, addr);
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| 23 | if (!pte)
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| 24 | return -ENOMEM;
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| 25 | do {
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| 26 | BUG_ON(!pte_none(*pte));
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| 27 | set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
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| 28 | pfn++;
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| 29 | } while (pte++, addr += PAGE_SIZE, addr != end);
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| 30 | return 0;
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| 31 | }
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| 32 |
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| 33 | static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
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| 34 | unsigned long end, unsigned long phys_addr, pgprot_t prot)
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| 35 | {
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| 36 | pmd_t *pmd;
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| 37 | unsigned long next;
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| 38 |
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| 39 | phys_addr -= addr;
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| 40 | pmd = pmd_alloc(&init_mm, pud, addr);
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| 41 | if (!pmd)
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| 42 | return -ENOMEM;
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| 43 | do {
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| 44 | next = pmd_addr_end(addr, end);
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| 45 | if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, prot))
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| 46 | return -ENOMEM;
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| 47 | } while (pmd++, addr = next, addr != end);
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| 48 | return 0;
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| 49 | }
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| 50 |
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| 51 | static inline int ioremap_pud_range(pgd_t *pgd, unsigned long addr,
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| 52 | unsigned long end, unsigned long phys_addr, pgprot_t prot)
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| 53 | {
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| 54 | pud_t *pud;
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| 55 | unsigned long next;
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| 56 |
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| 57 | phys_addr -= addr;
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| 58 | pud = pud_alloc(&init_mm, pgd, addr);
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| 59 | if (!pud)
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| 60 | return -ENOMEM;
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| 61 | do {
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| 62 | next = pud_addr_end(addr, end);
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| 63 | if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, prot))
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| 64 | return -ENOMEM;
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| 65 | } while (pud++, addr = next, addr != end);
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| 66 | return 0;
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| 67 | }
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| 68 |
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| 69 | int ioremap_page_range(unsigned long addr,
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| 70 | unsigned long end, unsigned long phys_addr, pgprot_t prot)
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| 71 | {
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| 72 | pgd_t *pgd;
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| 73 | unsigned long start;
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| 74 | unsigned long next;
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| 75 | int err;
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| 76 |
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| 77 | BUG_ON(addr >= end);
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| 78 |
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| 79 | start = addr;
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| 80 | phys_addr -= addr;
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| 81 | pgd = pgd_offset_k(addr);
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| 82 | do {
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| 83 | next = pgd_addr_end(addr, end);
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| 84 | err = ioremap_pud_range(pgd, addr, next, phys_addr+addr, prot);
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| 85 | if (err)
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| 86 | break;
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| 87 | } while (pgd++, addr = next, addr != end);
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| 88 |
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| 89 | flush_cache_vmap(start, end);
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| 90 |
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| 91 | return err;
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| 92 | }
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