1/*
2 * arch/sh/mm/ioremap.c
3 *
4 * (C) Copyright 1995 1996 Linus Torvalds
5 * (C) Copyright 2005 - 2010  Paul Mundt
6 *
7 * Re-map IO memory to kernel address space so that we can access it.
8 * This is needed for high PCI addresses that aren't mapped in the
9 * 640k-1MB IO memory area on PC's
10 *
11 * This file is subject to the terms and conditions of the GNU General
12 * Public License. See the file "COPYING" in the main directory of this
13 * archive for more details.
14 */
15#include <linux/vmalloc.h>
16#include <linux/module.h>
17#include <linux/slab.h>
18#include <linux/mm.h>
19#include <linux/pci.h>
20#include <linux/io.h>
21#include <asm/io_trapped.h>
22#include <asm/page.h>
23#include <asm/pgalloc.h>
24#include <asm/addrspace.h>
25#include <asm/cacheflush.h>
26#include <asm/tlbflush.h>
27#include <asm/mmu.h>
28#include "ioremap.h"
29
30/*
31 * On 32-bit SH, we traditionally have the whole physical address space mapped
32 * at all times (as MIPS does), so "ioremap()" and "iounmap()" do not need to do
33 * anything but place the address in the proper segment.  This is true for P1
34 * and P2 addresses, as well as some P3 ones.  However, most of the P3 addresses
35 * and newer cores using extended addressing need to map through page tables, so
36 * the ioremap() implementation becomes a bit more complicated.
37 */
38#ifdef CONFIG_29BIT
39static void __iomem *
40__ioremap_29bit(phys_addr_t offset, unsigned long size, pgprot_t prot)
41{
42	phys_addr_t last_addr = offset + size - 1;
43
44	/*
45	 * For P1 and P2 space this is trivial, as everything is already
46	 * mapped. Uncached access for P1 addresses are done through P2.
47	 * In the P3 case or for addresses outside of the 29-bit space,
48	 * mapping must be done by the PMB or by using page tables.
49	 */
50	if (likely(PXSEG(offset) < P3SEG && PXSEG(last_addr) < P3SEG)) {
51		u64 flags = pgprot_val(prot);
52
53		/*
54		 * Anything using the legacy PTEA space attributes needs
55		 * to be kicked down to page table mappings.
56		 */
57		if (unlikely(flags & _PAGE_PCC_MASK))
58			return NULL;
59		if (unlikely(flags & _PAGE_CACHABLE))
60			return (void __iomem *)P1SEGADDR(offset);
61
62		return (void __iomem *)P2SEGADDR(offset);
63	}
64
65	/* P4 above the store queues are always mapped. */
66	if (unlikely(offset >= P3_ADDR_MAX))
67		return (void __iomem *)P4SEGADDR(offset);
68
69	return NULL;
70}
71#else
72#define __ioremap_29bit(offset, size, prot)		NULL
73#endif /* CONFIG_29BIT */
74
75void __iomem __ref *ioremap_prot(phys_addr_t phys_addr, size_t size,
76				 unsigned long prot)
77{
78	void __iomem *mapped;
79	pgprot_t pgprot = __pgprot(prot);
80
81	mapped = __ioremap_trapped(phys_addr, size);
82	if (mapped)
83		return mapped;
84
85	mapped = __ioremap_29bit(phys_addr, size, pgprot);
86	if (mapped)
87		return mapped;
88
89	/*
90	 * If we can't yet use the regular approach, go the fixmap route.
91	 */
92	if (!mem_init_done)
93		return ioremap_fixed(phys_addr, size, pgprot);
94
95	/*
96	 * First try to remap through the PMB.
97	 * PMB entries are all pre-faulted.
98	 */
99	mapped = pmb_remap_caller(phys_addr, size, pgprot,
100			__builtin_return_address(0));
101	if (mapped && !IS_ERR(mapped))
102		return mapped;
103
104	return generic_ioremap_prot(phys_addr, size, pgprot);
105}
106EXPORT_SYMBOL(ioremap_prot);
107
108/*
109 * Simple checks for non-translatable mappings.
110 */
111static inline int iomapping_nontranslatable(unsigned long offset)
112{
113#ifdef CONFIG_29BIT
114	/*
115	 * In 29-bit mode this includes the fixed P1/P2 areas, as well as
116	 * parts of P3.
117	 */
118	if (PXSEG(offset) < P3SEG || offset >= P3_ADDR_MAX)
119		return 1;
120#endif
121
122	return 0;
123}
124
125void iounmap(volatile void __iomem *addr)
126{
127	unsigned long vaddr = (unsigned long __force)addr;
128
129	/*
130	 * Nothing to do if there is no translatable mapping.
131	 */
132	if (iomapping_nontranslatable(vaddr))
133		return;
134
135	/*
136	 * There's no VMA if it's from an early fixed mapping.
137	 */
138	if (iounmap_fixed((void __iomem *)addr) == 0)
139		return;
140
141	/*
142	 * If the PMB handled it, there's nothing else to do.
143	 */
144	if (pmb_unmap((void __iomem *)addr) == 0)
145		return;
146
147	generic_iounmap(addr);
148}
149EXPORT_SYMBOL(iounmap);
150