xref: /kernel/linux/linux-5.10/arch/parisc/mm/ioremap.c (revision 8c2ecf20) 
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 <linux/mm.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 */
28void __iomem *ioremap(unsigned long phys_addr, unsigned long size)
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#endif
42
43	/* Don't allow wraparound or zero size */
44	last_addr = phys_addr + size - 1;
45	if (!size || last_addr < phys_addr)
46		return NULL;
47
48	/*
49	 * Don't allow anybody to remap normal RAM that we're using..
50	 */
51	if (phys_addr < virt_to_phys(high_memory)) {
52		char *t_addr, *t_end;
53		struct page *page;
54
55		t_addr = __va(phys_addr);
56		t_end = t_addr + (size - 1);
57
58		for (page = virt_to_page(t_addr);
59		     page <= virt_to_page(t_end); page++) {
60			if(!PageReserved(page))
61				return NULL;
62		}
63	}
64
65	pgprot = __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY |
66			  _PAGE_ACCESSED | _PAGE_NO_CACHE);
67
68	/*
69	 * Mappings have to be page-aligned
70	 */
71	offset = phys_addr & ~PAGE_MASK;
72	phys_addr &= PAGE_MASK;
73	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
74
75	/*
76	 * Ok, go for it..
77	 */
78	area = get_vm_area(size, VM_IOREMAP);
79	if (!area)
80		return NULL;
81
82	addr = (void __iomem *) area->addr;
83	if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
84			       phys_addr, pgprot)) {
85		vunmap(addr);
86		return NULL;
87	}
88
89	return (void __iomem *) (offset + (char __iomem *)addr);
90}
91EXPORT_SYMBOL(ioremap);
92
93void iounmap(const volatile void __iomem *io_addr)
94{
95	unsigned long addr = (unsigned long)io_addr & PAGE_MASK;
96
97	if (is_vmalloc_addr((void *)addr))
98		vunmap((void *)addr);
99}
100EXPORT_SYMBOL(iounmap);
101