arch/powerpc/mm/ioremap_32.c

   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         pr_warn("ioremap() called early from %pS. Use early_ioremap() instead\n", caller);
  72
  73         err = early_ioremap_range(ioremap_bot - size, p, size, prot);
  74         if (err)
  75                 return NULL;
  76         ioremap_bot -= size;
  77
  78         return (void __iomem *)ioremap_bot + offset;
  79 }
  80
  81 void iounmap(volatile void __iomem *addr)
  82 {
  83         /*
  84          * If mapped by BATs then there is nothing to do.
  85          * Calling vfree() generates a benign warning.
  86          */
  87         if (v_block_mapped((unsigned long)addr))
  88                 return;
  89
  90         if (addr > high_memory && (unsigned long)addr < ioremap_bot)
  91                 vunmap((void *)(PAGE_MASK & (unsigned long)addr));
  92 }
  93 EXPORT_SYMBOL(iounmap);