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
|
/*
* Copyright 2010 Benjamin Herrenschmidt, IBM Corp
* <benh@kernel.crashing.org>
* and David Gibson, IBM Corporation.
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef _ASM_POWERPC_SCOM_H
#define _ASM_POWERPC_SCOM_H
#ifdef __KERNEL__
#ifndef __ASSEMBLY__
#ifdef CONFIG_PPC_SCOM
/*
* The SCOM bus is a sideband bus used for accessing various internal
* registers of the processor or the chipset. The implementation details
* differ between processors and platforms, and the access method as
* well.
*
* This API allows to "map" ranges of SCOM register numbers associated
* with a given SCOM controller. The later must be represented by a
* device node, though some implementations might support NULL if there
* is no possible ambiguity
*
* Then, scom_read/scom_write can be used to accesses registers inside
* that range. The argument passed is a register number relative to
* the beginning of the range mapped.
*/
typedef void *scom_map_t;
/* Value for an invalid SCOM map */
#define SCOM_MAP_INVALID (NULL)
/* The scom_controller data structure is what the platform passes
* to the core code in scom_init, it provides the actual implementation
* of all the SCOM functions
*/
struct scom_controller {
scom_map_t (*map)(struct device_node *ctrl_dev, u64 reg, u64 count);
void (*unmap)(scom_map_t map);
int (*read)(scom_map_t map, u64 reg, u64 *value);
int (*write)(scom_map_t map, u64 reg, u64 value);
};
extern const struct scom_controller *scom_controller;
/**
* scom_init - Initialize the SCOM backend, called by the platform
* @controller: The platform SCOM controller
*/
static inline void scom_init(const struct scom_controller *controller)
{
scom_controller = controller;
}
/**
* scom_map_ok - Test is a SCOM mapping is successful
* @map: The result of scom_map to test
*/
static inline int scom_map_ok(scom_map_t map)
{
return map != SCOM_MAP_INVALID;
}
/**
* scom_map - Map a block of SCOM registers
* @ctrl_dev: Device node of the SCOM controller
* some implementations allow NULL here
* @reg: first SCOM register to map
* @count: Number of SCOM registers to map
*/
static inline scom_map_t scom_map(struct device_node *ctrl_dev,
u64 reg, u64 count)
{
return scom_controller->map(ctrl_dev, reg, count);
}
/**
* scom_find_parent - Find the SCOM controller for a device
* @dev: OF node of the device
*
* This is not meant for general usage, but in combination with
* scom_map() allows to map registers not represented by the
* device own scom-reg property. Useful for applying HW workarounds
* on things not properly represented in the device-tree for example.
*/
struct device_node *scom_find_parent(struct device_node *dev);
/**
* scom_map_device - Map a device's block of SCOM registers
* @dev: OF node of the device
* @index: Register bank index (index in "scom-reg" property)
*
* This function will use the device-tree binding for SCOM which
* is to follow "scom-parent" properties until it finds a node with
* a "scom-controller" property to find the controller. It will then
* use the "scom-reg" property which is made of reg/count pairs,
* each of them having a size defined by the controller's #scom-cells
* property
*/
extern scom_map_t scom_map_device(struct device_node *dev, int index);
/**
* scom_unmap - Unmap a block of SCOM registers
* @map: Result of scom_map is to be unmapped
*/
static inline void scom_unmap(scom_map_t map)
{
if (scom_map_ok(map))
scom_controller->unmap(map);
}
/**
* scom_read - Read a SCOM register
* @map: Result of scom_map
* @reg: Register index within that map
* @value: Updated with the value read
*
* Returns 0 (success) or a negative error code
*/
static inline int scom_read(scom_map_t map, u64 reg, u64 *value)
{
int rc;
rc = scom_controller->read(map, reg, value);
if (rc)
*value = 0xfffffffffffffffful;
return rc;
}
/**
* scom_write - Write to a SCOM register
* @map: Result of scom_map
* @reg: Register index within that map
* @value: Value to write
*
* Returns 0 (success) or a negative error code
*/
static inline int scom_write(scom_map_t map, u64 reg, u64 value)
{
return scom_controller->write(map, reg, value);
}
#endif /* CONFIG_PPC_SCOM */
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_SCOM_H */
|
