Pawel Moll | 3ecbf05 | 2012-09-24 14:55:40 +0100 | [diff] [blame] | 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 | } |
Guenter Roeck | a17155b | 2013-01-06 01:16:19 -0800 | [diff] [blame] | 70 | EXPORT_SYMBOL(vexpress_config_bridge_register); |
Pawel Moll | 3ecbf05 | 2012-09-24 14:55:40 +0100 | [diff] [blame] | 71 | |
| 72 | void 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 | } |
Guenter Roeck | a17155b | 2013-01-06 01:16:19 -0800 | [diff] [blame] | 87 | EXPORT_SYMBOL(vexpress_config_bridge_unregister); |
Pawel Moll | 3ecbf05 | 2012-09-24 14:55:40 +0100 | [diff] [blame] | 88 | |
| 89 | |
| 90 | struct vexpress_config_func { |
| 91 | struct vexpress_config_bridge *bridge; |
| 92 | void *func; |
| 93 | }; |
| 94 | |
| 95 | struct 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 | } |
Guenter Roeck | a17155b | 2013-01-06 01:16:19 -0800 | [diff] [blame] | 147 | EXPORT_SYMBOL(__vexpress_config_func_get); |
Pawel Moll | 3ecbf05 | 2012-09-24 14:55:40 +0100 | [diff] [blame] | 148 | |
| 149 | void 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 | } |
Guenter Roeck | a17155b | 2013-01-06 01:16:19 -0800 | [diff] [blame] | 155 | EXPORT_SYMBOL(vexpress_config_func_put); |
Pawel Moll | 3ecbf05 | 2012-09-24 14:55:40 +0100 | [diff] [blame] | 156 | |
| 157 | struct 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 | |
| 167 | static 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 | |
| 176 | static 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 | |
| 210 | void 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 | } |
Guenter Roeck | a17155b | 2013-01-06 01:16:19 -0800 | [diff] [blame] | 235 | EXPORT_SYMBOL(vexpress_config_complete); |
Pawel Moll | 3ecbf05 | 2012-09-24 14:55:40 +0100 | [diff] [blame] | 236 | |
| 237 | int vexpress_config_wait(struct vexpress_config_trans *trans) |
| 238 | { |
| 239 | wait_for_completion(&trans->completion); |
| 240 | |
| 241 | return trans->status; |
| 242 | } |
Guenter Roeck | a17155b | 2013-01-06 01:16:19 -0800 | [diff] [blame] | 243 | EXPORT_SYMBOL(vexpress_config_wait); |
Pawel Moll | 3ecbf05 | 2012-09-24 14:55:40 +0100 | [diff] [blame] | 244 | |
| 245 | int 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 | } |
| 262 | EXPORT_SYMBOL(vexpress_config_read); |
| 263 | |
| 264 | int 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 | } |
| 281 | EXPORT_SYMBOL(vexpress_config_write); |