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3ecbf05b PM |
1 | /* |
2 | * This program is free software; you can redistribute it and/or modify | |
3 | * it under the terms of the GNU General Public License version 2 as | |
4 | * published by the Free Software Foundation. | |
5 | * | |
6 | * This program is distributed in the hope that it will be useful, | |
7 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
8 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
9 | * GNU General Public License for more details. | |
10 | * | |
11 | * Copyright (C) 2012 ARM Limited | |
12 | */ | |
13 | ||
14 | #define pr_fmt(fmt) "vexpress-config: " fmt | |
15 | ||
16 | #include <linux/bitops.h> | |
17 | #include <linux/completion.h> | |
18 | #include <linux/export.h> | |
19 | #include <linux/init.h> | |
20 | #include <linux/list.h> | |
21 | #include <linux/of.h> | |
22 | #include <linux/of_device.h> | |
23 | #include <linux/slab.h> | |
24 | #include <linux/string.h> | |
25 | #include <linux/vexpress.h> | |
26 | ||
27 | ||
28 | #define VEXPRESS_CONFIG_MAX_BRIDGES 2 | |
29 | ||
30 | struct vexpress_config_bridge { | |
31 | struct device_node *node; | |
32 | struct vexpress_config_bridge_info *info; | |
33 | struct list_head transactions; | |
34 | spinlock_t transactions_lock; | |
35 | } vexpress_config_bridges[VEXPRESS_CONFIG_MAX_BRIDGES]; | |
36 | ||
37 | static DECLARE_BITMAP(vexpress_config_bridges_map, | |
38 | ARRAY_SIZE(vexpress_config_bridges)); | |
39 | static DEFINE_MUTEX(vexpress_config_bridges_mutex); | |
40 | ||
41 | struct vexpress_config_bridge *vexpress_config_bridge_register( | |
42 | struct device_node *node, | |
43 | struct vexpress_config_bridge_info *info) | |
44 | { | |
45 | struct vexpress_config_bridge *bridge; | |
46 | int i; | |
47 | ||
48 | pr_debug("Registering bridge '%s'\n", info->name); | |
49 | ||
50 | mutex_lock(&vexpress_config_bridges_mutex); | |
51 | i = find_first_zero_bit(vexpress_config_bridges_map, | |
52 | ARRAY_SIZE(vexpress_config_bridges)); | |
53 | if (i >= ARRAY_SIZE(vexpress_config_bridges)) { | |
54 | pr_err("Can't register more bridges!\n"); | |
55 | mutex_unlock(&vexpress_config_bridges_mutex); | |
56 | return NULL; | |
57 | } | |
58 | __set_bit(i, vexpress_config_bridges_map); | |
59 | bridge = &vexpress_config_bridges[i]; | |
60 | ||
61 | bridge->node = node; | |
62 | bridge->info = info; | |
63 | INIT_LIST_HEAD(&bridge->transactions); | |
64 | spin_lock_init(&bridge->transactions_lock); | |
65 | ||
66 | mutex_unlock(&vexpress_config_bridges_mutex); | |
67 | ||
68 | return bridge; | |
69 | } | |
70 | ||
71 | void vexpress_config_bridge_unregister(struct vexpress_config_bridge *bridge) | |
72 | { | |
73 | struct vexpress_config_bridge __bridge = *bridge; | |
74 | int i; | |
75 | ||
76 | mutex_lock(&vexpress_config_bridges_mutex); | |
77 | for (i = 0; i < ARRAY_SIZE(vexpress_config_bridges); i++) | |
78 | if (&vexpress_config_bridges[i] == bridge) | |
79 | __clear_bit(i, vexpress_config_bridges_map); | |
80 | mutex_unlock(&vexpress_config_bridges_mutex); | |
81 | ||
82 | WARN_ON(!list_empty(&__bridge.transactions)); | |
83 | while (!list_empty(&__bridge.transactions)) | |
84 | cpu_relax(); | |
85 | } | |
86 | ||
87 | ||
88 | struct vexpress_config_func { | |
89 | struct vexpress_config_bridge *bridge; | |
90 | void *func; | |
91 | }; | |
92 | ||
93 | struct vexpress_config_func *__vexpress_config_func_get(struct device *dev, | |
94 | struct device_node *node) | |
95 | { | |
96 | struct device_node *bridge_node; | |
97 | struct vexpress_config_func *func; | |
98 | int i; | |
99 | ||
100 | if (WARN_ON(dev && node && dev->of_node != node)) | |
101 | return NULL; | |
102 | if (dev && !node) | |
103 | node = dev->of_node; | |
104 | ||
105 | func = kzalloc(sizeof(*func), GFP_KERNEL); | |
106 | if (!func) | |
107 | return NULL; | |
108 | ||
109 | bridge_node = of_node_get(node); | |
110 | while (bridge_node) { | |
111 | const __be32 *prop = of_get_property(bridge_node, | |
112 | "arm,vexpress,config-bridge", NULL); | |
113 | ||
114 | if (prop) { | |
115 | bridge_node = of_find_node_by_phandle( | |
116 | be32_to_cpup(prop)); | |
117 | break; | |
118 | } | |
119 | ||
120 | bridge_node = of_get_next_parent(bridge_node); | |
121 | } | |
122 | ||
123 | mutex_lock(&vexpress_config_bridges_mutex); | |
124 | for (i = 0; i < ARRAY_SIZE(vexpress_config_bridges); i++) { | |
125 | struct vexpress_config_bridge *bridge = | |
126 | &vexpress_config_bridges[i]; | |
127 | ||
128 | if (test_bit(i, vexpress_config_bridges_map) && | |
129 | bridge->node == bridge_node) { | |
130 | func->bridge = bridge; | |
131 | func->func = bridge->info->func_get(dev, node); | |
132 | break; | |
133 | } | |
134 | } | |
135 | mutex_unlock(&vexpress_config_bridges_mutex); | |
136 | ||
137 | if (!func->func) { | |
138 | of_node_put(node); | |
139 | kfree(func); | |
140 | return NULL; | |
141 | } | |
142 | ||
143 | return func; | |
144 | } | |
145 | ||
146 | void vexpress_config_func_put(struct vexpress_config_func *func) | |
147 | { | |
148 | func->bridge->info->func_put(func->func); | |
149 | of_node_put(func->bridge->node); | |
150 | kfree(func); | |
151 | } | |
152 | ||
153 | ||
154 | struct vexpress_config_trans { | |
155 | struct vexpress_config_func *func; | |
156 | int offset; | |
157 | bool write; | |
158 | u32 *data; | |
159 | int status; | |
160 | struct completion completion; | |
161 | struct list_head list; | |
162 | }; | |
163 | ||
164 | static void vexpress_config_dump_trans(const char *what, | |
165 | struct vexpress_config_trans *trans) | |
166 | { | |
167 | pr_debug("%s %s trans %p func 0x%p offset %d data 0x%x status %d\n", | |
168 | what, trans->write ? "write" : "read", trans, | |
169 | trans->func->func, trans->offset, | |
170 | trans->data ? *trans->data : 0, trans->status); | |
171 | } | |
172 | ||
173 | static int vexpress_config_schedule(struct vexpress_config_trans *trans) | |
174 | { | |
175 | int status; | |
176 | struct vexpress_config_bridge *bridge = trans->func->bridge; | |
177 | unsigned long flags; | |
178 | ||
179 | init_completion(&trans->completion); | |
180 | trans->status = -EFAULT; | |
181 | ||
182 | spin_lock_irqsave(&bridge->transactions_lock, flags); | |
183 | ||
184 | vexpress_config_dump_trans("Executing", trans); | |
185 | ||
186 | if (list_empty(&bridge->transactions)) | |
187 | status = bridge->info->func_exec(trans->func->func, | |
188 | trans->offset, trans->write, trans->data); | |
189 | else | |
190 | status = VEXPRESS_CONFIG_STATUS_WAIT; | |
191 | ||
192 | switch (status) { | |
193 | case VEXPRESS_CONFIG_STATUS_DONE: | |
194 | vexpress_config_dump_trans("Finished", trans); | |
195 | trans->status = status; | |
196 | break; | |
197 | case VEXPRESS_CONFIG_STATUS_WAIT: | |
198 | list_add_tail(&trans->list, &bridge->transactions); | |
199 | break; | |
200 | } | |
201 | ||
202 | spin_unlock_irqrestore(&bridge->transactions_lock, flags); | |
203 | ||
204 | return status; | |
205 | } | |
206 | ||
207 | void vexpress_config_complete(struct vexpress_config_bridge *bridge, | |
208 | int status) | |
209 | { | |
210 | struct vexpress_config_trans *trans; | |
211 | unsigned long flags; | |
212 | ||
213 | spin_lock_irqsave(&bridge->transactions_lock, flags); | |
214 | ||
215 | trans = list_first_entry(&bridge->transactions, | |
216 | struct vexpress_config_trans, list); | |
217 | vexpress_config_dump_trans("Completed", trans); | |
218 | ||
219 | trans->status = status; | |
220 | list_del(&trans->list); | |
221 | ||
222 | if (!list_empty(&bridge->transactions)) { | |
223 | vexpress_config_dump_trans("Pending", trans); | |
224 | ||
225 | bridge->info->func_exec(trans->func->func, trans->offset, | |
226 | trans->write, trans->data); | |
227 | } | |
228 | spin_unlock_irqrestore(&bridge->transactions_lock, flags); | |
229 | ||
230 | complete(&trans->completion); | |
231 | } | |
232 | ||
233 | int vexpress_config_wait(struct vexpress_config_trans *trans) | |
234 | { | |
235 | wait_for_completion(&trans->completion); | |
236 | ||
237 | return trans->status; | |
238 | } | |
239 | ||
240 | ||
241 | int vexpress_config_read(struct vexpress_config_func *func, int offset, | |
242 | u32 *data) | |
243 | { | |
244 | struct vexpress_config_trans trans = { | |
245 | .func = func, | |
246 | .offset = offset, | |
247 | .write = false, | |
248 | .data = data, | |
249 | .status = 0, | |
250 | }; | |
251 | int status = vexpress_config_schedule(&trans); | |
252 | ||
253 | if (status == VEXPRESS_CONFIG_STATUS_WAIT) | |
254 | status = vexpress_config_wait(&trans); | |
255 | ||
256 | return status; | |
257 | } | |
258 | EXPORT_SYMBOL(vexpress_config_read); | |
259 | ||
260 | int vexpress_config_write(struct vexpress_config_func *func, int offset, | |
261 | u32 data) | |
262 | { | |
263 | struct vexpress_config_trans trans = { | |
264 | .func = func, | |
265 | .offset = offset, | |
266 | .write = true, | |
267 | .data = &data, | |
268 | .status = 0, | |
269 | }; | |
270 | int status = vexpress_config_schedule(&trans); | |
271 | ||
272 | if (status == VEXPRESS_CONFIG_STATUS_WAIT) | |
273 | status = vexpress_config_wait(&trans); | |
274 | ||
275 | return status; | |
276 | } | |
277 | EXPORT_SYMBOL(vexpress_config_write); |