projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
| 373cd784 JH |
2 | /* |
| 3 | * Re-map IO memory to kernel address space so that we can access it. | |
| 4 | * Needed for memory-mapped I/O devices mapped outside our normal DRAM | |
| 5 | * window (that is, all memory-mapped I/O devices). | |
| 6 | * | |
| 7 | * Copyright (C) 1995,1996 Linus Torvalds | |
| 8 | * | |
| 9 | * Meta port based on CRIS-port by Axis Communications AB | |
| 10 | */ | |
| 11 | ||
| 12 | #include <linux/vmalloc.h> | |
| 13 | #include <linux/io.h> | |
| 14 | #include <linux/export.h> | |
| 15 | #include <linux/slab.h> | |
| 16 | #include <linux/mm.h> | |
| 17 | ||
| 18 | #include <asm/pgtable.h> | |
| 19 | ||
| 20 | /* | |
| 21 | * Remap an arbitrary physical address space into the kernel virtual | |
| 22 | * address space. Needed when the kernel wants to access high addresses | |
| 23 | * directly. | |
| 24 | * | |
| 25 | * NOTE! We need to allow non-page-aligned mappings too: we will obviously | |
| 26 | * have to convert them into an offset in a page-aligned mapping, but the | |
| 27 | * caller shouldn't need to know that small detail. | |
| 28 | */ | |
| 29 | void __iomem *__ioremap(unsigned long phys_addr, size_t size, | |
| 30 | unsigned long flags) | |
| 31 | { | |
| 32 | unsigned long addr; | |
| 33 | struct vm_struct *area; | |
| 34 | unsigned long offset, last_addr; | |
| 35 | pgprot_t prot; | |
| 36 | ||
| 37 | /* Don't allow wraparound or zero size */ | |
| 38 | last_addr = phys_addr + size - 1; | |
| 39 | if (!size || last_addr < phys_addr) | |
| 40 | return NULL; | |
| 41 | ||
| 42 | /* Custom region addresses are accessible and uncached by default. */ | |
| 43 | if (phys_addr >= LINSYSCUSTOM_BASE && | |
| 44 | phys_addr < (LINSYSCUSTOM_BASE + LINSYSCUSTOM_LIMIT)) | |
| 45 | return (__force void __iomem *) phys_addr; | |
| 46 | ||
| 47 | /* | |
| 48 | * Mappings have to be page-aligned | |
| 49 | */ | |
| 50 | offset = phys_addr & ~PAGE_MASK; | |
| 51 | phys_addr &= PAGE_MASK; | |
| 52 | size = PAGE_ALIGN(last_addr+1) - phys_addr; | |
| 53 | prot = __pgprot(_PAGE_PRESENT | _PAGE_WRITE | _PAGE_DIRTY | | |
| 54 | _PAGE_ACCESSED | _PAGE_KERNEL | _PAGE_CACHE_WIN0 | | |
| 55 | flags); | |
| 56 | ||
| 57 | /* | |
| 58 | * Ok, go for it.. | |
| 59 | */ | |
| 60 | area = get_vm_area(size, VM_IOREMAP); | |
| 61 | if (!area) | |
| 62 | return NULL; | |
| 63 | area->phys_addr = phys_addr; | |
| 64 | addr = (unsigned long) area->addr; | |
| 65 | if (ioremap_page_range(addr, addr + size, phys_addr, prot)) { | |
| 66 | vunmap((void *) addr); | |
| 67 | return NULL; | |
| 68 | } | |
| 69 | return (__force void __iomem *) (offset + (char *)addr); | |
| 70 | } | |
| 71 | EXPORT_SYMBOL(__ioremap); | |
| 72 | ||
| 73 | void __iounmap(void __iomem *addr) | |
| 74 | { | |
| 75 | struct vm_struct *p; | |
| 76 | ||
| 77 | if ((__force unsigned long)addr >= LINSYSCUSTOM_BASE && | |
| 78 | (__force unsigned long)addr < (LINSYSCUSTOM_BASE + | |
| 79 | LINSYSCUSTOM_LIMIT)) | |
| 80 | return; | |
| 81 | ||
| 82 | p = remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr)); | |
| 83 | if (unlikely(!p)) { | |
| 84 | pr_err("iounmap: bad address %p\n", addr); | |
| 85 | return; | |
| 86 | } | |
| 87 | ||
| 88 | kfree(p); | |
| 89 | } | |
| 90 | EXPORT_SYMBOL(__iounmap); |