arch/cris/mm/ioremap.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * arch/cris/mm/ioremap.c
   4  *
   5  * Re-map IO memory to kernel address space so that we can access it.
   6  * Needed for memory-mapped I/O devices mapped outside our normal DRAM
   7  * window (that is, all memory-mapped I/O devices).
   8  *
   9  * (C) Copyright 1995 1996 Linus Torvalds
  10  * CRIS-port by Axis Communications AB
  11  */
  12
  13 #include <linux/vmalloc.h>
  14 #include <linux/io.h>
  15 #include <asm/pgalloc.h>
  16 #include <arch/memmap.h>
  17
  18 /*
  19  * Generic mapping function (not visible outside):
  20  */
  21
  22 /*
  23  * Remap an arbitrary physical address space into the kernel virtual
  24  * address space. Needed when the kernel wants to access high addresses
  25  * directly.
  26  *
  27  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
  28  * have to convert them into an offset in a page-aligned mapping, but the
  29  * caller shouldn't need to know that small detail.
  30  */
  31 void __iomem * __ioremap_prot(unsigned long phys_addr, unsigned long size, pgprot_t prot)
  32 {
  33         void __iomem * addr;
  34         struct vm_struct * area;
  35         unsigned long offset, last_addr;
  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         /*
  43          * Mappings have to be page-aligned
  44          */
  45         offset = phys_addr & ~PAGE_MASK;
  46         phys_addr &= PAGE_MASK;
  47         size = PAGE_ALIGN(last_addr+1) - phys_addr;
  48
  49         /*
  50          * Ok, go for it..
  51          */
  52         area = get_vm_area(size, VM_IOREMAP);
  53         if (!area)
  54                 return NULL;
  55         addr = (void __iomem *)area->addr;
  56         if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
  57                                phys_addr, prot)) {
  58                 vfree((void __force *)addr);
  59                 return NULL;
  60         }
  61         return (void __iomem *) (offset + (char __iomem *)addr);
  62 }
  63
  64 void __iomem * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
  65 {
  66         return __ioremap_prot(phys_addr, size,
  67                               __pgprot(_PAGE_PRESENT | __READABLE |
  68                                        __WRITEABLE | _PAGE_GLOBAL |
  69                                        _PAGE_KERNEL | flags));
  70 }
  71
  72 /**
  73  * ioremap_nocache     -   map bus memory into CPU space
  74  * @offset:    bus address of the memory
  75  * @size:      size of the resource to map
  76  *
  77  * Must be freed with iounmap.
  78  */
  79
  80 void __iomem *ioremap_nocache(unsigned long phys_addr, unsigned long size)
  81 {
  82         return __ioremap(phys_addr | MEM_NON_CACHEABLE, size, 0);
  83 }
  84 EXPORT_SYMBOL(ioremap_nocache);
  85
  86 void iounmap(volatile void __iomem *addr)
  87 {
  88         if (addr > high_memory)
  89                 return vfree((void *) (PAGE_MASK & (unsigned long) addr));
  90 }