1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * (C) Copyright 1995 1996 Linus Torvalds
7  * (C) Copyright 2001, 2002 Ralf Baechle
8  */
9 #include <linux/export.h>
10 #include <asm/addrspace.h>
11 #include <asm/byteorder.h>
12 #include <linux/ioport.h>
13 #include <linux/sched.h>
14 #include <linux/slab.h>
15 #include <linux/vmalloc.h>
16 #include <linux/mm_types.h>
17 #include <linux/io.h>
18 #include <asm/cacheflush.h>
19 #include <asm/tlbflush.h>
20 #include <ioremap.h>
21 
22 #define IS_LOW512(addr) (!((phys_addr_t)(addr) & (phys_addr_t) ~0x1fffffffULL))
23 #define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1)
24 
__ioremap_check_ram(unsigned long start_pfn,unsigned long nr_pages,void * arg)25 static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages,
26 			       void *arg)
27 {
28 	unsigned long i;
29 
30 	for (i = 0; i < nr_pages; i++) {
31 		if (pfn_valid(start_pfn + i) &&
32 		    !PageReserved(pfn_to_page(start_pfn + i)))
33 			return 1;
34 	}
35 
36 	return 0;
37 }
38 
39 /*
40  * ioremap_prot     -   map bus memory into CPU space
41  * @phys_addr:    bus address of the memory
42  * @size:      size of the resource to map
43  *
44  * ioremap_prot gives the caller control over cache coherency attributes (CCA)
45  */
ioremap_prot(phys_addr_t phys_addr,unsigned long size,unsigned long prot_val)46 void __iomem *ioremap_prot(phys_addr_t phys_addr, unsigned long size,
47 		unsigned long prot_val)
48 {
49 	unsigned long flags = prot_val & _CACHE_MASK;
50 	unsigned long offset, pfn, last_pfn;
51 	struct vm_struct *area;
52 	phys_addr_t last_addr;
53 	unsigned long vaddr;
54 	void __iomem *cpu_addr;
55 
56 	cpu_addr = plat_ioremap(phys_addr, size, flags);
57 	if (cpu_addr)
58 		return cpu_addr;
59 
60 	phys_addr = fixup_bigphys_addr(phys_addr, size);
61 
62 	/* Don't allow wraparound or zero size */
63 	last_addr = phys_addr + size - 1;
64 	if (!size || last_addr < phys_addr)
65 		return NULL;
66 
67 	/*
68 	 * Map uncached objects in the low 512mb of address space using KSEG1,
69 	 * otherwise map using page tables.
70 	 */
71 	if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) &&
72 	    flags == _CACHE_UNCACHED)
73 		return (void __iomem *) CKSEG1ADDR(phys_addr);
74 
75 	/*
76 	 * Don't allow anybody to remap RAM that may be allocated by the page
77 	 * allocator, since that could lead to races & data clobbering.
78 	 */
79 	pfn = PFN_DOWN(phys_addr);
80 	last_pfn = PFN_DOWN(last_addr);
81 	if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL,
82 				  __ioremap_check_ram) == 1) {
83 		WARN_ONCE(1, "ioremap on RAM at %pa - %pa\n",
84 			  &phys_addr, &last_addr);
85 		return NULL;
86 	}
87 
88 	/*
89 	 * Mappings have to be page-aligned
90 	 */
91 	offset = phys_addr & ~PAGE_MASK;
92 	phys_addr &= PAGE_MASK;
93 	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
94 
95 	/*
96 	 * Ok, go for it..
97 	 */
98 	area = get_vm_area(size, VM_IOREMAP);
99 	if (!area)
100 		return NULL;
101 	vaddr = (unsigned long)area->addr;
102 
103 	flags |= _PAGE_GLOBAL | _PAGE_PRESENT | __READABLE | __WRITEABLE;
104 	if (ioremap_page_range(vaddr, vaddr + size, phys_addr,
105 			__pgprot(flags))) {
106 		free_vm_area(area);
107 		return NULL;
108 	}
109 
110 	return (void __iomem *)(vaddr + offset);
111 }
112 EXPORT_SYMBOL(ioremap_prot);
113 
iounmap(const volatile void __iomem * addr)114 void iounmap(const volatile void __iomem *addr)
115 {
116 	if (!plat_iounmap(addr) && !IS_KSEG1(addr))
117 		vunmap((void *)((unsigned long)addr & PAGE_MASK));
118 }
119 EXPORT_SYMBOL(iounmap);
120