arch/ia64/mm/ioremap.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * (c) Copyright 2006, 2007 Hewlett-Packard Development Company, L.P.
   4  *      Bjorn Helgaas <bjorn.helgaas@hp.com>
   5  */
   6
   7 #include <linux/compiler.h>
   8 #include <linux/module.h>
   9 #include <linux/efi.h>
  10 #include <linux/io.h>
  11 #include <linux/vmalloc.h>
  12 #include <asm/io.h>
  13 #include <asm/meminit.h>
  14
  15 static inline void __iomem *
  16 __ioremap_uc(unsigned long phys_addr)
  17 {
  18         return (void __iomem *) (__IA64_UNCACHED_OFFSET | phys_addr);
  19 }
  20
  21 void __iomem *
  22 early_ioremap (unsigned long phys_addr, unsigned long size)
  23 {
  24         u64 attr;
  25         attr = kern_mem_attribute(phys_addr, size);
  26         if (attr & EFI_MEMORY_WB)
  27                 return (void __iomem *) phys_to_virt(phys_addr);
  28         return __ioremap_uc(phys_addr);
  29 }
  30
  31 void __iomem *
  32 ioremap (unsigned long phys_addr, unsigned long size)
  33 {
  34         void __iomem *addr;
  35         struct vm_struct *area;
  36         unsigned long offset;
  37         pgprot_t prot;
  38         u64 attr;
  39         unsigned long gran_base, gran_size;
  40         unsigned long page_base;
  41
  42         /*
  43          * For things in kern_memmap, we must use the same attribute
  44          * as the rest of the kernel.  For more details, see
  45          * Documentation/ia64/aliasing.rst.
  46          */
  47         attr = kern_mem_attribute(phys_addr, size);
  48         if (attr & EFI_MEMORY_WB)
  49                 return (void __iomem *) phys_to_virt(phys_addr);
  50         else if (attr & EFI_MEMORY_UC)
  51                 return __ioremap_uc(phys_addr);
  52
  53         /*
  54          * Some chipsets don't support UC access to memory.  If
  55          * WB is supported for the whole granule, we prefer that.
  56          */
  57         gran_base = GRANULEROUNDDOWN(phys_addr);
  58         gran_size = GRANULEROUNDUP(phys_addr + size) - gran_base;
  59         if (efi_mem_attribute(gran_base, gran_size) & EFI_MEMORY_WB)
  60                 return (void __iomem *) phys_to_virt(phys_addr);
  61
  62         /*
  63          * WB is not supported for the whole granule, so we can't use
  64          * the region 7 identity mapping.  If we can safely cover the
  65          * area with kernel page table mappings, we can use those
  66          * instead.
  67          */
  68         page_base = phys_addr & PAGE_MASK;
  69         size = PAGE_ALIGN(phys_addr + size) - page_base;
  70         if (efi_mem_attribute(page_base, size) & EFI_MEMORY_WB) {
  71                 prot = PAGE_KERNEL;
  72
  73                 /*
  74                  * Mappings have to be page-aligned
  75                  */
  76                 offset = phys_addr & ~PAGE_MASK;
  77                 phys_addr &= PAGE_MASK;
  78
  79                 /*
  80                  * Ok, go for it..
  81                  */
  82                 area = get_vm_area(size, VM_IOREMAP);
  83                 if (!area)
  84                         return NULL;
  85
  86                 area->phys_addr = phys_addr;
  87                 addr = (void __iomem *) area->addr;
  88                 if (ioremap_page_range((unsigned long) addr,
  89                                 (unsigned long) addr + size, phys_addr, prot)) {
  90                         vunmap((void __force *) addr);
  91                         return NULL;
  92                 }
  93
  94                 return (void __iomem *) (offset + (char __iomem *)addr);
  95         }
  96
  97         return __ioremap_uc(phys_addr);
  98 }
  99 EXPORT_SYMBOL(ioremap);
 100
 101 void __iomem *
 102 ioremap_uc(unsigned long phys_addr, unsigned long size)
 103 {
 104         if (kern_mem_attribute(phys_addr, size) & EFI_MEMORY_WB)
 105                 return NULL;
 106
 107         return __ioremap_uc(phys_addr);
 108 }
 109 EXPORT_SYMBOL(ioremap_uc);
 110
 111 void
 112 early_iounmap (volatile void __iomem *addr, unsigned long size)
 113 {
 114 }
 115
 116 void
 117 iounmap (volatile void __iomem *addr)
 118 {
 119         if (REGION_NUMBER(addr) == RGN_GATE)
 120                 vunmap((void *) ((unsigned long) addr & PAGE_MASK));
 121 }
 122 EXPORT_SYMBOL(iounmap);