root/arch/powerpc/mm/ioremap_32.c

DEFINITIONS

1. ioremap_wt
2. __ioremap_caller
3. iounmap

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 
   3 #include <linux/io.h>
   4 #include <linux/slab.h>
   5 #include <linux/vmalloc.h>
   6 
   7 #include <mm/mmu_decl.h>
   8 
   9 void __iomem *ioremap_wt(phys_addr_t addr, unsigned long size)
  10 {
  11         pgprot_t prot = pgprot_cached_wthru(PAGE_KERNEL);
  12 
  13         return __ioremap_caller(addr, size, prot, __builtin_return_address(0));
  14 }
  15 EXPORT_SYMBOL(ioremap_wt);
  16 
  17 void __iomem *
  18 __ioremap_caller(phys_addr_t addr, unsigned long size, pgprot_t prot, void *caller)
  19 {
  20         unsigned long v;
  21         phys_addr_t p, offset;
  22         int err;
  23 
  24         /*
  25          * Choose an address to map it to.
  26          * Once the vmalloc system is running, we use it.
  27          * Before then, we use space going down from IOREMAP_TOP
  28          * (ioremap_bot records where we're up to).
  29          */
  30         p = addr & PAGE_MASK;
  31         offset = addr & ~PAGE_MASK;
  32         size = PAGE_ALIGN(addr + size) - p;
  33 
  34         /*
  35          * If the address lies within the first 16 MB, assume it's in ISA
  36          * memory space
  37          */
  38         if (p < 16 * 1024 * 1024)
  39                 p += _ISA_MEM_BASE;
  40 
  41 #ifndef CONFIG_CRASH_DUMP
  42         /*
  43          * Don't allow anybody to remap normal RAM that we're using.
  44          * mem_init() sets high_memory so only do the check after that.
  45          */
  46         if (slab_is_available() && p <= virt_to_phys(high_memory - 1) &&
  47             page_is_ram(__phys_to_pfn(p))) {
  48                 pr_warn("%s(): phys addr 0x%llx is RAM lr %ps\n", __func__,
  49                         (unsigned long long)p, __builtin_return_address(0));
  50                 return NULL;
  51         }
  52 #endif
  53 
  54         if (size == 0)
  55                 return NULL;
  56 
  57         /*
  58          * Is it already mapped?  Perhaps overlapped by a previous
  59          * mapping.
  60          */
  61         v = p_block_mapped(p);
  62         if (v)
  63                 return (void __iomem *)v + offset;
  64 
  65         if (slab_is_available())
  66                 return do_ioremap(p, offset, size, prot, caller);
  67 
  68         /*
  69          * Should check if it is a candidate for a BAT mapping
  70          */
  71 
  72         err = early_ioremap_range(ioremap_bot - size, p, size, prot);
  73         if (err)
  74                 return NULL;
  75         ioremap_bot -= size;
  76 
  77         return (void __iomem *)ioremap_bot + offset;
  78 }
  79 
  80 void iounmap(volatile void __iomem *addr)
  81 {
  82         /*
  83          * If mapped by BATs then there is nothing to do.
  84          * Calling vfree() generates a benign warning.
  85          */
  86         if (v_block_mapped((unsigned long)addr))
  87                 return;
  88 
  89         if (addr > high_memory && (unsigned long)addr < ioremap_bot)
  90                 vunmap((void *)(PAGE_MASK & (unsigned long)addr));
  91 }
  92 EXPORT_SYMBOL(iounmap);