aboutsummaryrefslogtreecommitdiff
path: root/arch/mips/include/asm/mach-powertv/ioremap.h
blob: c86ef094ec37c0f5b6a0ca22243b110c33f59dbb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
/*
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 *
 * Portions Copyright (C)  Cisco Systems, Inc.
 */
#ifndef __ASM_MACH_POWERTV_IOREMAP_H
#define __ASM_MACH_POWERTV_IOREMAP_H

#include <linux/types.h>
#include <linux/log2.h>
#include <linux/compiler.h>

#include <asm/pgtable-bits.h>
#include <asm/addrspace.h>

/* We're going to mess with bits, so get sizes */
#define IOR_BPC			8			/* Bits per char */
#define IOR_PHYS_BITS		(IOR_BPC * sizeof(phys_addr_t))
#define IOR_DMA_BITS		(IOR_BPC * sizeof(dma_addr_t))

/*
 * Define the granularity of physical/DMA mapping in terms of the number
 * of bits that defines the offset within a grain. These will be the
 * least significant bits of the address. The rest of a physical or DMA
 * address will be used to index into an appropriate table to find the
 * offset to add to the address to yield the corresponding DMA or physical
 * address, respectively.
 */
#define IOR_LSBITS		22			/* Bits in a grain */

/*
 * Compute the number of most significant address bits after removing those
 * used for the offset within a grain and then compute the number of table
 * entries for the conversion.
 */
#define IOR_PHYS_MSBITS		(IOR_PHYS_BITS - IOR_LSBITS)
#define IOR_NUM_PHYS_TO_DMA	((phys_addr_t) 1 << IOR_PHYS_MSBITS)

#define IOR_DMA_MSBITS		(IOR_DMA_BITS - IOR_LSBITS)
#define IOR_NUM_DMA_TO_PHYS	((dma_addr_t) 1 << IOR_DMA_MSBITS)

/*
 * Define data structures used as elements in the arrays for the conversion
 * between physical and DMA addresses. We do some slightly fancy math to
 * compute the width of the offset element of the conversion tables so
 * that we can have the smallest conversion tables. Next, round up the
 * sizes to the next higher power of two, i.e. the offset element will have
 * 8, 16, 32, 64, etc. bits. This eliminates the need to mask off any
 * bits.  Finally, we compute a shift value that puts the most significant
 * bits of the offset into the most significant bits of the offset element.
 * This makes it more efficient on processors without barrel shifters and
 * easier to see the values if the conversion table is dumped in binary.
 */
#define _IOR_OFFSET_WIDTH(n)	(1 << order_base_2(n))
#define IOR_OFFSET_WIDTH(n) \
	(_IOR_OFFSET_WIDTH(n) < 8 ? 8 : _IOR_OFFSET_WIDTH(n))

#define IOR_PHYS_OFFSET_BITS	IOR_OFFSET_WIDTH(IOR_PHYS_MSBITS)
#define IOR_PHYS_SHIFT		(IOR_PHYS_BITS - IOR_PHYS_OFFSET_BITS)

#define IOR_DMA_OFFSET_BITS	IOR_OFFSET_WIDTH(IOR_DMA_MSBITS)
#define IOR_DMA_SHIFT		(IOR_DMA_BITS - IOR_DMA_OFFSET_BITS)

struct ior_phys_to_dma {
	dma_addr_t offset:IOR_DMA_OFFSET_BITS __packed
		__aligned((IOR_DMA_OFFSET_BITS / IOR_BPC));
};

struct ior_dma_to_phys {
	dma_addr_t offset:IOR_PHYS_OFFSET_BITS __packed
		__aligned((IOR_PHYS_OFFSET_BITS / IOR_BPC));
};

extern struct ior_phys_to_dma _ior_phys_to_dma[IOR_NUM_PHYS_TO_DMA];
extern struct ior_dma_to_phys _ior_dma_to_phys[IOR_NUM_DMA_TO_PHYS];

static inline dma_addr_t _phys_to_dma_offset_raw(phys_addr_t phys)
{
	return (dma_addr_t)_ior_phys_to_dma[phys >> IOR_LSBITS].offset;
}

static inline dma_addr_t _dma_to_phys_offset_raw(dma_addr_t dma)
{
	return (dma_addr_t)_ior_dma_to_phys[dma >> IOR_LSBITS].offset;
}

/* These are not portable and should not be used in drivers. Drivers should
 * be using ioremap() and friends to map physical addresses to virtual
 * addresses and dma_map*() and friends to map virtual addresses into DMA
 * addresses and back.
 */
static inline dma_addr_t phys_to_dma(phys_addr_t phys)
{
	return phys + (_phys_to_dma_offset_raw(phys) << IOR_PHYS_SHIFT);
}

static inline phys_addr_t dma_to_phys(dma_addr_t dma)
{
	return dma + (_dma_to_phys_offset_raw(dma) << IOR_DMA_SHIFT);
}

extern void ioremap_add_map(dma_addr_t phys, phys_addr_t alias,
	dma_addr_t size);

/*
 * Allow physical addresses to be fixed up to help peripherals located
 * outside the low 32-bit range -- generic pass-through version.
 */
static inline phys_t fixup_bigphys_addr(phys_t phys_addr, phys_t size)
{
	return phys_addr;
}

/*
 * Handle the special case of addresses the area aliased into the first
 * 512 MiB of the processor's physical address space. These turn into either
 * kseg0 or kseg1 addresses, depending on flags.
 */
static inline void __iomem *plat_ioremap(phys_t start, unsigned long size,
	unsigned long flags)
{
	phys_addr_t start_offset;
	void __iomem *result = NULL;

	/* Start by checking to see whether this is an aliased address */
	start_offset = _dma_to_phys_offset_raw(start);

	/*
	 * If:
	 * o	the memory is aliased into the first 512 MiB, and
	 * o	the start and end are in the same RAM bank, and
	 * o	we don't have a zero size or wrap around, and
	 * o	we are supposed to create an uncached mapping,
	 *	handle this is a kseg0 or kseg1 address
	 */
	if (start_offset != 0) {
		phys_addr_t last;
		dma_addr_t dma_to_phys_offset;

		last = start + size - 1;
		dma_to_phys_offset =
			_dma_to_phys_offset_raw(last) << IOR_DMA_SHIFT;

		if (dma_to_phys_offset == start_offset &&
			size != 0 && start <= last) {
			phys_t adjusted_start;
			adjusted_start = start + start_offset;
			if (flags == _CACHE_UNCACHED)
				result = (void __iomem *) (unsigned long)
					CKSEG1ADDR(adjusted_start);
			else
				result = (void __iomem *) (unsigned long)
					CKSEG0ADDR(adjusted_start);
		}
	}

	return result;
}

static inline int plat_iounmap(const volatile void __iomem *addr)
{
	return 0;
}
#endif /* __ASM_MACH_POWERTV_IOREMAP_H */