ioremap.c

 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/cache.h>
12
13static inline bool arc_uncached_addr_space(phys_addr_t paddr)
14{
15	if (is_isa_arcompact()) {
16		if (paddr >= ARC_UNCACHED_ADDR_SPACE)
17			return true;
18	} else if (paddr >= perip_base && paddr <= perip_end) {
19		return true;
20	}
21
22	return false;
23}
24
25void __iomem *ioremap(phys_addr_t paddr, unsigned long size)
26{
27	/*
28	 * If the region is h/w uncached, MMU mapping can be elided as optim
29	 * The cast to u32 is fine as this region can only be inside 4GB
30	 */
31	if (arc_uncached_addr_space(paddr))
32		return (void __iomem *)(u32)paddr;
33
34	return ioremap_prot(paddr, size,
35			    pgprot_noncached(PAGE_KERNEL));
36}
37EXPORT_SYMBOL(ioremap);
38
39/*
40 * ioremap with access flags
41 * Cache semantics wise it is same as ioremap - "forced" uncached.
42 * However unlike vanilla ioremap which bypasses ARC MMU for addresses in
43 * ARC hardware uncached region, this one still goes thru the MMU as caller
44 * might need finer access control (R/W/X)
45 */
46void __iomem *ioremap_prot(phys_addr_t paddr, size_t size,
47			   pgprot_t prot)
48{
49	/* force uncached */
50	return generic_ioremap_prot(paddr, size, pgprot_noncached(prot));
51}
52EXPORT_SYMBOL(ioremap_prot);
53
54void iounmap(volatile void __iomem *addr)
55{
56	/* weird double cast to handle phys_addr_t > 32 bits */
57	if (arc_uncached_addr_space((phys_addr_t)(u32)addr))
58		return;
59
60	generic_iounmap(addr);
61}
62EXPORT_SYMBOL(iounmap);