root/arch/arc/mm/ioremap.c

DEFINITIONS

1. arc_uncached_addr_space
2. ioremap
3. ioremap_prot
4. iounmap

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
   4  */
   5 
   6 #include <linux/vmalloc.h>
   7 #include <linux/init.h>
   8 #include <linux/module.h>
   9 #include <linux/io.h>
  10 #include <linux/mm.h>
  11 #include <linux/slab.h>
  12 #include <linux/cache.h>
  13 
  14 static inline bool arc_uncached_addr_space(phys_addr_t paddr)
  15 {
  16         if (is_isa_arcompact()) {
  17                 if (paddr >= ARC_UNCACHED_ADDR_SPACE)
  18                         return true;
  19         } else if (paddr >= perip_base && paddr <= perip_end) {
  20                 return true;
  21         }
  22 
  23         return false;
  24 }
  25 
  26 void __iomem *ioremap(phys_addr_t paddr, unsigned long size)
  27 {
  28         phys_addr_t end;
  29 
  30         /* Don't allow wraparound or zero size */
  31         end = paddr + size - 1;
  32         if (!size || (end < paddr))
  33                 return NULL;
  34 
  35         /*
  36          * If the region is h/w uncached, MMU mapping can be elided as optim
  37          * The cast to u32 is fine as this region can only be inside 4GB
  38          */
  39         if (arc_uncached_addr_space(paddr))
  40                 return (void __iomem *)(u32)paddr;
  41 
  42         return ioremap_prot(paddr, size, PAGE_KERNEL_NO_CACHE);
  43 }
  44 EXPORT_SYMBOL(ioremap);
  45 
  46 /*
  47  * ioremap with access flags
  48  * Cache semantics wise it is same as ioremap - "forced" uncached.
  49  * However unlike vanilla ioremap which bypasses ARC MMU for addresses in
  50  * ARC hardware uncached region, this one still goes thru the MMU as caller
  51  * might need finer access control (R/W/X)
  52  */
  53 void __iomem *ioremap_prot(phys_addr_t paddr, unsigned long size,
  54                            unsigned long flags)
  55 {
  56         unsigned long vaddr;
  57         struct vm_struct *area;
  58         phys_addr_t off, end;
  59         pgprot_t prot = __pgprot(flags);
  60 
  61         /* Don't allow wraparound, zero size */
  62         end = paddr + size - 1;
  63         if ((!size) || (end < paddr))
  64                 return NULL;
  65 
  66         /* An early platform driver might end up here */
  67         if (!slab_is_available())
  68                 return NULL;
  69 
  70         /* force uncached */
  71         prot = pgprot_noncached(prot);
  72 
  73         /* Mappings have to be page-aligned */
  74         off = paddr & ~PAGE_MASK;
  75         paddr &= PAGE_MASK;
  76         size = PAGE_ALIGN(end + 1) - paddr;
  77 
  78         /*
  79          * Ok, go for it..
  80          */
  81         area = get_vm_area(size, VM_IOREMAP);
  82         if (!area)
  83                 return NULL;
  84         area->phys_addr = paddr;
  85         vaddr = (unsigned long)area->addr;
  86         if (ioremap_page_range(vaddr, vaddr + size, paddr, prot)) {
  87                 vunmap((void __force *)vaddr);
  88                 return NULL;
  89         }
  90         return (void __iomem *)(off + (char __iomem *)vaddr);
  91 }
  92 EXPORT_SYMBOL(ioremap_prot);
  93 
  94 
  95 void iounmap(const void __iomem *addr)
  96 {
  97         /* weird double cast to handle phys_addr_t > 32 bits */
  98         if (arc_uncached_addr_space((phys_addr_t)(u32)addr))
  99                 return;
 100 
 101         vfree((void *)(PAGE_MASK & (unsigned long __force)addr));
 102 }
 103 EXPORT_SYMBOL(iounmap);