1
2
3
4
5
6
7
8
9
10
11
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
30struct 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
37static DECLARE_BITMAP(vexpress_config_bridges_map,
38 ARRAY_SIZE(vexpress_config_bridges));
39static DEFINE_MUTEX(vexpress_config_bridges_mutex);
40
41struct 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}
70EXPORT_SYMBOL(vexpress_config_bridge_register);
71
72void vexpress_config_bridge_unregister(struct vexpress_config_bridge *bridge)
73{
74 struct vexpress_config_bridge __bridge = *bridge;
75 int i;
76
77 mutex_lock(&vexpress_config_bridges_mutex);
78 for (i = 0; i < ARRAY_SIZE(vexpress_config_bridges); i++)
79 if (&vexpress_config_bridges[i] == bridge)
80 __clear_bit(i, vexpress_config_bridges_map);
81 mutex_unlock(&vexpress_config_bridges_mutex);
82
83 WARN_ON(!list_empty(&__bridge.transactions));
84 while (!list_empty(&__bridge.transactions))
85 cpu_relax();
86}
87EXPORT_SYMBOL(vexpress_config_bridge_unregister);
88
89
90struct vexpress_config_func {
91 struct vexpress_config_bridge *bridge;
92 void *func;
93};
94
95struct vexpress_config_func *__vexpress_config_func_get(struct device *dev,
96 struct device_node *node)
97{
98 struct device_node *bridge_node;
99 struct vexpress_config_func *func;
100 int i;
101
102 if (WARN_ON(dev && node && dev->of_node != node))
103 return NULL;
104 if (dev && !node)
105 node = dev->of_node;
106
107 func = kzalloc(sizeof(*func), GFP_KERNEL);
108 if (!func)
109 return NULL;
110
111 bridge_node = of_node_get(node);
112 while (bridge_node) {
113 const __be32 *prop = of_get_property(bridge_node,
114 "arm,vexpress,config-bridge", NULL);
115
116 if (prop) {
117 bridge_node = of_find_node_by_phandle(
118 be32_to_cpup(prop));
119 break;
120 }
121
122 bridge_node = of_get_next_parent(bridge_node);
123 }
124
125 mutex_lock(&vexpress_config_bridges_mutex);
126 for (i = 0; i < ARRAY_SIZE(vexpress_config_bridges); i++) {
127 struct vexpress_config_bridge *bridge =
128 &vexpress_config_bridges[i];
129
130 if (test_bit(i, vexpress_config_bridges_map) &&
131 bridge->node == bridge_node) {
132 func->bridge = bridge;
133 func->func = bridge->info->func_get(dev, node);
134 break;
135 }
136 }
137 mutex_unlock(&vexpress_config_bridges_mutex);
138
139 if (!func->func) {
140 of_node_put(node);
141 kfree(func);
142 return NULL;
143 }
144
145 return func;
146}
147EXPORT_SYMBOL(__vexpress_config_func_get);
148
149void vexpress_config_func_put(struct vexpress_config_func *func)
150{
151 func->bridge->info->func_put(func->func);
152 of_node_put(func->bridge->node);
153 kfree(func);
154}
155EXPORT_SYMBOL(vexpress_config_func_put);
156
157struct vexpress_config_trans {
158 struct vexpress_config_func *func;
159 int offset;
160 bool write;
161 u32 *data;
162 int status;
163 struct completion completion;
164 struct list_head list;
165};
166
167static void vexpress_config_dump_trans(const char *what,
168 struct vexpress_config_trans *trans)
169{
170 pr_debug("%s %s trans %p func 0x%p offset %d data 0x%x status %d\n",
171 what, trans->write ? "write" : "read", trans,
172 trans->func->func, trans->offset,
173 trans->data ? *trans->data : 0, trans->status);
174}
175
176static int vexpress_config_schedule(struct vexpress_config_trans *trans)
177{
178 int status;
179 struct vexpress_config_bridge *bridge = trans->func->bridge;
180 unsigned long flags;
181
182 init_completion(&trans->completion);
183 trans->status = -EFAULT;
184
185 spin_lock_irqsave(&bridge->transactions_lock, flags);
186
187 vexpress_config_dump_trans("Executing", trans);
188
189 if (list_empty(&bridge->transactions))
190 status = bridge->info->func_exec(trans->func->func,
191 trans->offset, trans->write, trans->data);
192 else
193 status = VEXPRESS_CONFIG_STATUS_WAIT;
194
195 switch (status) {
196 case VEXPRESS_CONFIG_STATUS_DONE:
197 vexpress_config_dump_trans("Finished", trans);
198 trans->status = status;
199 break;
200 case VEXPRESS_CONFIG_STATUS_WAIT:
201 list_add_tail(&trans->list, &bridge->transactions);
202 break;
203 }
204
205 spin_unlock_irqrestore(&bridge->transactions_lock, flags);
206
207 return status;
208}
209
210void vexpress_config_complete(struct vexpress_config_bridge *bridge,
211 int status)
212{
213 struct vexpress_config_trans *trans;
214 unsigned long flags;
215
216 spin_lock_irqsave(&bridge->transactions_lock, flags);
217
218 trans = list_first_entry(&bridge->transactions,
219 struct vexpress_config_trans, list);
220 vexpress_config_dump_trans("Completed", trans);
221
222 trans->status = status;
223 list_del(&trans->list);
224
225 if (!list_empty(&bridge->transactions)) {
226 vexpress_config_dump_trans("Pending", trans);
227
228 bridge->info->func_exec(trans->func->func, trans->offset,
229 trans->write, trans->data);
230 }
231 spin_unlock_irqrestore(&bridge->transactions_lock, flags);
232
233 complete(&trans->completion);
234}
235EXPORT_SYMBOL(vexpress_config_complete);
236
237int vexpress_config_wait(struct vexpress_config_trans *trans)
238{
239 wait_for_completion(&trans->completion);
240
241 return trans->status;
242}
243EXPORT_SYMBOL(vexpress_config_wait);
244
245int vexpress_config_read(struct vexpress_config_func *func, int offset,
246 u32 *data)
247{
248 struct vexpress_config_trans trans = {
249 .func = func,
250 .offset = offset,
251 .write = false,
252 .data = data,
253 .status = 0,
254 };
255 int status = vexpress_config_schedule(&trans);
256
257 if (status == VEXPRESS_CONFIG_STATUS_WAIT)
258 status = vexpress_config_wait(&trans);
259
260 return status;
261}
262EXPORT_SYMBOL(vexpress_config_read);
263
264int vexpress_config_write(struct vexpress_config_func *func, int offset,
265 u32 data)
266{
267 struct vexpress_config_trans trans = {
268 .func = func,
269 .offset = offset,
270 .write = true,
271 .data = &data,
272 .status = 0,
273 };
274 int status = vexpress_config_schedule(&trans);
275
276 if (status == VEXPRESS_CONFIG_STATUS_WAIT)
277 status = vexpress_config_wait(&trans);
278
279 return status;
280}
281EXPORT_SYMBOL(vexpress_config_write);
282
