xref: /openbmc/linux/arch/parisc/mm/ioremap.c (revision fb8d6c8d)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * arch/parisc/mm/ioremap.c
4  *
5  * (C) Copyright 1995 1996 Linus Torvalds
6  * (C) Copyright 2001-2019 Helge Deller <deller@gmx.de>
7  * (C) Copyright 2005 Kyle McMartin <kyle@parisc-linux.org>
8  */
9 
10 #include <linux/vmalloc.h>
11 #include <linux/errno.h>
12 #include <linux/module.h>
13 #include <linux/io.h>
14 #include <asm/pgalloc.h>
15 
16 /*
17  * Generic mapping function (not visible outside):
18  */
19 
20 /*
21  * Remap an arbitrary physical address space into the kernel virtual
22  * address space.
23  *
24  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
25  * have to convert them into an offset in a page-aligned mapping, but the
26  * caller shouldn't need to know that small detail.
27  */
28 void __iomem * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
29 {
30 	void __iomem *addr;
31 	struct vm_struct *area;
32 	unsigned long offset, last_addr;
33 	pgprot_t pgprot;
34 
35 #ifdef CONFIG_EISA
36 	unsigned long end = phys_addr + size - 1;
37 	/* Support EISA addresses */
38 	if ((phys_addr >= 0x00080000 && end < 0x000fffff) ||
39 	    (phys_addr >= 0x00500000 && end < 0x03bfffff)) {
40 		phys_addr |= F_EXTEND(0xfc000000);
41 		flags |= _PAGE_NO_CACHE;
42 	}
43 #endif
44 
45 	/* Don't allow wraparound or zero size */
46 	last_addr = phys_addr + size - 1;
47 	if (!size || last_addr < phys_addr)
48 		return NULL;
49 
50 	/*
51 	 * Don't allow anybody to remap normal RAM that we're using..
52 	 */
53 	if (phys_addr < virt_to_phys(high_memory)) {
54 		char *t_addr, *t_end;
55 		struct page *page;
56 
57 		t_addr = __va(phys_addr);
58 		t_end = t_addr + (size - 1);
59 
60 		for (page = virt_to_page(t_addr);
61 		     page <= virt_to_page(t_end); page++) {
62 			if(!PageReserved(page))
63 				return NULL;
64 		}
65 	}
66 
67 	pgprot = __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY |
68 			  _PAGE_ACCESSED | flags);
69 
70 	/*
71 	 * Mappings have to be page-aligned
72 	 */
73 	offset = phys_addr & ~PAGE_MASK;
74 	phys_addr &= PAGE_MASK;
75 	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
76 
77 	/*
78 	 * Ok, go for it..
79 	 */
80 	area = get_vm_area(size, VM_IOREMAP);
81 	if (!area)
82 		return NULL;
83 
84 	addr = (void __iomem *) area->addr;
85 	if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
86 			       phys_addr, pgprot)) {
87 		vunmap(addr);
88 		return NULL;
89 	}
90 
91 	return (void __iomem *) (offset + (char __iomem *)addr);
92 }
93 EXPORT_SYMBOL(__ioremap);
94 
95 void iounmap(const volatile void __iomem *io_addr)
96 {
97 	unsigned long addr = (unsigned long)io_addr & PAGE_MASK;
98 
99 	if (is_vmalloc_addr((void *)addr))
100 		vunmap((void *)addr);
101 }
102 EXPORT_SYMBOL(iounmap);
103