Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 1 | /* |
| 2 | * Greybus operations |
| 3 | * |
| 4 | * Copyright 2014 Google Inc. |
| 5 | * |
| 6 | * Released under the GPLv2 only. |
| 7 | */ |
| 8 | |
| 9 | #include <linux/kernel.h> |
| 10 | #include <linux/slab.h> |
| 11 | #include <linux/module.h> |
| 12 | #include <linux/workqueue.h> |
| 13 | |
| 14 | #include "greybus.h" |
| 15 | |
| 16 | /* |
Alex Elder | 22b320f | 2014-10-16 06:35:31 -0500 | [diff] [blame] | 17 | * The top bit of the type in an operation message header indicates |
| 18 | * whether the message is a request (bit clear) or response (bit set) |
| 19 | */ |
| 20 | #define GB_OPERATION_TYPE_RESPONSE 0x80 |
| 21 | |
| 22 | /* |
Alex Elder | d90c25b | 2014-10-16 06:35:33 -0500 | [diff] [blame^] | 23 | * XXX This needs to be coordinated with host driver parameters |
| 24 | */ |
| 25 | #define GB_OPERATION_MESSAGE_SIZE_MAX 4096 |
| 26 | |
| 27 | /* |
Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 28 | * All operation messages (both requests and responses) begin with |
| 29 | * a common header that encodes the size of the data (header |
| 30 | * included). This header also contains a unique identifier, which |
| 31 | * is used to keep track of in-flight operations. Finally, the |
| 32 | * header contains a operation type field, whose interpretation is |
| 33 | * dependent on what type of device lies on the other end of the |
| 34 | * connection. Response messages are distinguished from request |
| 35 | * messages by setting the high bit (0x80) in the operation type |
| 36 | * value. |
| 37 | * |
| 38 | * The wire format for all numeric fields in the header is little |
| 39 | * endian. Any operation-specific data begins immediately after the |
| 40 | * header, and is 64-bit aligned. |
| 41 | */ |
| 42 | struct gb_operation_msg_hdr { |
| 43 | __le16 size; /* Size in bytes of header + payload */ |
| 44 | __le16 id; /* Operation unique id */ |
| 45 | __u8 type; /* E.g GB_I2C_TYPE_* or GB_GPIO_TYPE_* */ |
| 46 | /* 3 bytes pad, must be zero (ignore when read) */ |
| 47 | } __aligned(sizeof(u64)); |
| 48 | |
| 49 | /* XXX Could be per-host device, per-module, or even per-connection */ |
| 50 | static DEFINE_SPINLOCK(gb_operations_lock); |
| 51 | |
Alex Elder | 84d148b | 2014-10-16 06:35:32 -0500 | [diff] [blame] | 52 | static void gb_operation_insert(struct gb_operation *operation) |
| 53 | { |
| 54 | struct gb_connection *connection = operation->connection; |
| 55 | struct rb_root *root = &connection->pending; |
| 56 | struct rb_node *node = &operation->node; |
| 57 | struct rb_node **link = &root->rb_node; |
| 58 | struct rb_node *above = NULL; |
| 59 | struct gb_operation_msg_hdr *header; |
| 60 | __le16 wire_id; |
| 61 | |
| 62 | /* |
| 63 | * Assign the operation's id, and store it in the header of |
| 64 | * both request and response message headers. |
| 65 | */ |
| 66 | operation->id = gb_connection_operation_id(connection); |
| 67 | wire_id = cpu_to_le16(operation->id); |
| 68 | header = operation->request->transfer_buffer; |
| 69 | header->id = wire_id; |
| 70 | |
| 71 | /* OK, insert the operation into its connection's tree */ |
| 72 | spin_lock_irq(&gb_operations_lock); |
| 73 | |
| 74 | while (*link) { |
| 75 | struct gb_operation *other; |
| 76 | |
| 77 | above = *link; |
| 78 | other = rb_entry(above, struct gb_operation, node); |
| 79 | header = other->request->transfer_buffer; |
| 80 | if (other->id > operation->id) |
| 81 | link = &above->rb_left; |
| 82 | else if (other->id < operation->id) |
| 83 | link = &above->rb_right; |
| 84 | } |
| 85 | rb_link_node(node, above, link); |
| 86 | rb_insert_color(node, root); |
| 87 | |
| 88 | spin_unlock_irq(&gb_operations_lock); |
| 89 | } |
| 90 | |
| 91 | static void gb_operation_remove(struct gb_operation *operation) |
| 92 | { |
| 93 | spin_lock_irq(&gb_operations_lock); |
| 94 | rb_erase(&operation->node, &operation->connection->pending); |
| 95 | spin_unlock_irq(&gb_operations_lock); |
| 96 | } |
| 97 | |
| 98 | static struct gb_operation * |
| 99 | gb_operation_find(struct gb_connection *connection, u16 id) |
| 100 | { |
Alex Elder | d90c25b | 2014-10-16 06:35:33 -0500 | [diff] [blame^] | 101 | struct gb_operation *operation = NULL; |
Alex Elder | 84d148b | 2014-10-16 06:35:32 -0500 | [diff] [blame] | 102 | struct rb_node *node; |
| 103 | bool found = false; |
| 104 | |
| 105 | spin_lock_irq(&gb_operations_lock); |
| 106 | node = connection->pending.rb_node; |
| 107 | while (node && !found) { |
| 108 | operation = rb_entry(node, struct gb_operation, node); |
| 109 | if (operation->id > id) |
| 110 | node = node->rb_left; |
| 111 | else if (operation->id < id) |
| 112 | node = node->rb_right; |
| 113 | else |
| 114 | found = true; |
| 115 | } |
| 116 | spin_unlock_irq(&gb_operations_lock); |
| 117 | |
| 118 | return found ? operation : NULL; |
| 119 | } |
| 120 | |
Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 121 | /* |
| 122 | * An operations's response message has arrived. If no callback was |
| 123 | * supplied it was submitted for asynchronous completion, so we notify |
| 124 | * any waiters. Otherwise we assume calling the completion is enough |
| 125 | * and nobody else will be waiting. |
| 126 | */ |
| 127 | void gb_operation_complete(struct gb_operation *operation) |
| 128 | { |
Alex Elder | d90c25b | 2014-10-16 06:35:33 -0500 | [diff] [blame^] | 129 | /* XXX Should probably report bad status if no callback */ |
Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 130 | if (operation->callback) |
| 131 | operation->callback(operation); |
| 132 | else |
| 133 | complete_all(&operation->completion); |
Alex Elder | d90c25b | 2014-10-16 06:35:33 -0500 | [diff] [blame^] | 134 | gb_operation_destroy(operation); |
Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 135 | } |
| 136 | |
| 137 | /* |
| 138 | * Wait for a submitted operatnoi to complete */ |
| 139 | int gb_operation_wait(struct gb_operation *operation) |
| 140 | { |
| 141 | int ret; |
| 142 | |
| 143 | ret = wait_for_completion_interruptible(&operation->completion); |
| 144 | /* If interrupted, cancel the in-flight buffer */ |
| 145 | if (ret < 0) |
Alex Elder | 22b320f | 2014-10-16 06:35:31 -0500 | [diff] [blame] | 146 | ret = greybus_kill_gbuf(operation->request); |
Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 147 | return ret; |
| 148 | |
| 149 | } |
| 150 | |
| 151 | /* |
Alex Elder | 22b320f | 2014-10-16 06:35:31 -0500 | [diff] [blame] | 152 | * Called when an operation buffer completes. |
Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 153 | */ |
Alex Elder | 22b320f | 2014-10-16 06:35:31 -0500 | [diff] [blame] | 154 | static void gb_operation_gbuf_complete(struct gbuf *gbuf) |
Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 155 | { |
Alex Elder | d90c25b | 2014-10-16 06:35:33 -0500 | [diff] [blame^] | 156 | /* Don't do anything */ |
Alex Elder | 84d148b | 2014-10-16 06:35:32 -0500 | [diff] [blame] | 157 | struct gb_operation *operation; |
| 158 | struct gb_operation_msg_hdr *header; |
| 159 | u16 id; |
| 160 | |
| 161 | /* |
| 162 | * This isn't right, but it keeps things balanced until we |
| 163 | * can set up operation response handling. |
| 164 | */ |
| 165 | header = gbuf->transfer_buffer; |
| 166 | id = le16_to_cpu(header->id); |
| 167 | operation = gb_operation_find(gbuf->connection, id); |
| 168 | if (operation) |
| 169 | gb_operation_remove(operation); |
| 170 | else |
| 171 | gb_connection_err(gbuf->connection, "operation not found"); |
Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 172 | } |
| 173 | |
| 174 | /* |
Alex Elder | 22b320f | 2014-10-16 06:35:31 -0500 | [diff] [blame] | 175 | * Allocate a buffer to be used for an operation request or response |
| 176 | * message. Both types of message contain a header, which is filled |
| 177 | * in here. W |
Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 178 | */ |
Alex Elder | 22b320f | 2014-10-16 06:35:31 -0500 | [diff] [blame] | 179 | struct gbuf *gb_operation_gbuf_create(struct gb_operation *operation, |
| 180 | u8 type, size_t size, bool outbound) |
Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 181 | { |
Alex Elder | 22b320f | 2014-10-16 06:35:31 -0500 | [diff] [blame] | 182 | struct gb_connection *connection = operation->connection; |
Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 183 | struct gb_operation_msg_hdr *header; |
| 184 | struct gbuf *gbuf; |
Alex Elder | 22b320f | 2014-10-16 06:35:31 -0500 | [diff] [blame] | 185 | gfp_t gfp_flags = outbound ? GFP_KERNEL : GFP_ATOMIC; |
Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 186 | |
Alex Elder | 22b320f | 2014-10-16 06:35:31 -0500 | [diff] [blame] | 187 | /* Operation buffers hold a header in addition to their payload */ |
Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 188 | size += sizeof(*header); |
Alex Elder | 22b320f | 2014-10-16 06:35:31 -0500 | [diff] [blame] | 189 | gbuf = greybus_alloc_gbuf(connection, gb_operation_gbuf_complete, |
| 190 | size, outbound, gfp_flags, operation); |
| 191 | if (!gbuf) |
Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 192 | return NULL; |
Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 193 | |
Alex Elder | 22b320f | 2014-10-16 06:35:31 -0500 | [diff] [blame] | 194 | /* Fill in the header structure */ |
| 195 | header = (struct gb_operation_msg_hdr *)gbuf->transfer_buffer; |
Greg Kroah-Hartman | 322543a | 2014-10-02 21:25:21 -0700 | [diff] [blame] | 196 | header->size = cpu_to_le16(size); |
Alex Elder | b0b6575 | 2014-10-03 15:05:20 -0500 | [diff] [blame] | 197 | header->id = 0; /* Filled in when submitted */ |
| 198 | header->type = type; |
Alex Elder | 22b320f | 2014-10-16 06:35:31 -0500 | [diff] [blame] | 199 | |
| 200 | return gbuf; |
| 201 | } |
| 202 | |
| 203 | /* |
| 204 | * Create a Greybus operation to be sent over the given connection. |
| 205 | * The request buffer will big enough for a payload of the given |
| 206 | * size. Outgoing requests must specify the size of the response |
| 207 | * buffer size, which must be sufficient to hold all expected |
| 208 | * response data. |
| 209 | * |
| 210 | * Incoming requests will supply a response size of 0, and in that |
| 211 | * case no response buffer is allocated. (A response always |
| 212 | * includes a status byte, so 0 is not a valid size.) Whatever |
| 213 | * handles the operation request is responsible for allocating the |
| 214 | * response buffer. |
| 215 | * |
| 216 | * Returns a pointer to the new operation or a null pointer if an |
| 217 | * error occurs. |
| 218 | */ |
| 219 | struct gb_operation *gb_operation_create(struct gb_connection *connection, |
| 220 | u8 type, size_t request_size, |
| 221 | size_t response_size) |
| 222 | { |
| 223 | struct gb_operation *operation; |
| 224 | gfp_t gfp_flags = response_size ? GFP_KERNEL : GFP_ATOMIC; |
| 225 | |
| 226 | if (!request_size) { |
| 227 | gb_connection_err(connection, "zero-sized request"); |
| 228 | return NULL; |
| 229 | } |
| 230 | |
| 231 | /* XXX Use a slab cache */ |
| 232 | operation = kzalloc(sizeof(*operation), gfp_flags); |
| 233 | if (!operation) |
| 234 | return NULL; |
| 235 | operation->connection = connection; /* XXX refcount? */ |
| 236 | |
| 237 | operation->request = gb_operation_gbuf_create(operation, type, |
| 238 | request_size, true); |
| 239 | if (!operation->request) { |
| 240 | kfree(operation); |
| 241 | return NULL; |
| 242 | } |
| 243 | operation->request_payload = operation->request->transfer_buffer + |
| 244 | sizeof(struct gb_operation_msg_hdr); |
| 245 | /* We always use the full request buffer */ |
| 246 | operation->request->actual_length = request_size; |
| 247 | |
| 248 | if (response_size) { |
| 249 | type |= GB_OPERATION_TYPE_RESPONSE; |
| 250 | operation->response = gb_operation_gbuf_create(operation, |
| 251 | type, response_size, false); |
| 252 | if (!operation->response) { |
| 253 | greybus_free_gbuf(operation->request); |
| 254 | kfree(operation); |
| 255 | return NULL; |
| 256 | } |
| 257 | operation->response_payload = |
| 258 | operation->response->transfer_buffer + |
| 259 | sizeof(struct gb_operation_msg_hdr); |
| 260 | } |
Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 261 | |
| 262 | operation->callback = NULL; /* set at submit time */ |
| 263 | init_completion(&operation->completion); |
| 264 | |
| 265 | spin_lock_irq(&gb_operations_lock); |
| 266 | list_add_tail(&operation->links, &connection->operations); |
| 267 | spin_unlock_irq(&gb_operations_lock); |
| 268 | |
| 269 | return operation; |
| 270 | } |
| 271 | |
| 272 | /* |
| 273 | * Destroy a previously created operation. |
| 274 | */ |
| 275 | void gb_operation_destroy(struct gb_operation *operation) |
| 276 | { |
| 277 | if (WARN_ON(!operation)) |
| 278 | return; |
| 279 | |
| 280 | /* XXX Make sure it's not in flight */ |
| 281 | spin_lock_irq(&gb_operations_lock); |
| 282 | list_del(&operation->links); |
| 283 | spin_unlock_irq(&gb_operations_lock); |
| 284 | |
Alex Elder | 22b320f | 2014-10-16 06:35:31 -0500 | [diff] [blame] | 285 | greybus_free_gbuf(operation->response); |
| 286 | greybus_free_gbuf(operation->request); |
Alex Elder | e88afa5 | 2014-10-01 21:54:15 -0500 | [diff] [blame] | 287 | |
| 288 | kfree(operation); |
| 289 | } |
Alex Elder | d90c25b | 2014-10-16 06:35:33 -0500 | [diff] [blame^] | 290 | |
| 291 | /* |
| 292 | * Send an operation request message. The caller has filled in |
| 293 | * any payload so the request message is ready to go. If non-null, |
| 294 | * the callback function supplied will be called when the response |
| 295 | * message has arrived indicating the operation is complete. A null |
| 296 | * callback function is used for a synchronous request; return from |
| 297 | * this function won't occur until the operation is complete (or an |
| 298 | * interrupt occurs). |
| 299 | */ |
| 300 | int gb_operation_request_send(struct gb_operation *operation, |
| 301 | gb_operation_callback callback) |
| 302 | { |
| 303 | int ret; |
| 304 | |
| 305 | /* |
| 306 | * XXX |
| 307 | * I think the order of operations is going to be |
| 308 | * significant, and if so, we may need a mutex to surround |
| 309 | * setting the operation id and submitting the gbuf. |
| 310 | */ |
| 311 | operation->callback = callback; |
| 312 | gb_operation_insert(operation); |
| 313 | ret = greybus_submit_gbuf(operation->request, GFP_KERNEL); |
| 314 | if (ret) |
| 315 | return ret; |
| 316 | if (!callback) |
| 317 | ret = gb_operation_wait(operation); |
| 318 | |
| 319 | return ret; |
| 320 | } |
| 321 | |
| 322 | /* |
| 323 | * Send a response for an incoming operation request. |
| 324 | */ |
| 325 | int gb_operation_response_send(struct gb_operation *operation) |
| 326 | { |
| 327 | /* XXX |
| 328 | * Caller needs to have set operation->response->actual_length |
| 329 | */ |
| 330 | gb_operation_remove(operation); |
| 331 | gb_operation_destroy(operation); |
| 332 | |
| 333 | return 0; |
| 334 | } |
| 335 | |
| 336 | void gb_connection_operation_recv(struct gb_connection *connection, |
| 337 | void *data, size_t size) |
| 338 | { |
| 339 | struct gb_operation_msg_hdr *header; |
| 340 | struct gb_operation *operation; |
| 341 | struct gbuf *gbuf; |
| 342 | u16 msg_size; |
| 343 | |
| 344 | if (size > GB_OPERATION_MESSAGE_SIZE_MAX) { |
| 345 | gb_connection_err(connection, "message too big"); |
| 346 | return; |
| 347 | } |
| 348 | |
| 349 | header = data; |
| 350 | msg_size = le16_to_cpu(header->size); |
| 351 | if (header->type & GB_OPERATION_TYPE_RESPONSE) { |
| 352 | u16 id = le16_to_cpu(header->id); |
| 353 | |
| 354 | operation = gb_operation_find(connection, id); |
| 355 | if (!operation) { |
| 356 | gb_connection_err(connection, "operation not found"); |
| 357 | return; |
| 358 | } |
| 359 | gb_operation_remove(operation); |
| 360 | gbuf = operation->response; |
| 361 | if (size > gbuf->transfer_buffer_length) { |
| 362 | gb_connection_err(connection, "recv buffer too small"); |
| 363 | return; |
| 364 | } |
| 365 | } else { |
| 366 | WARN_ON(msg_size != size); |
| 367 | operation = gb_operation_create(connection, header->type, |
| 368 | msg_size, 0); |
| 369 | if (!operation) { |
| 370 | gb_connection_err(connection, "can't create operation"); |
| 371 | return; |
| 372 | } |
| 373 | gbuf = operation->request; |
| 374 | } |
| 375 | |
| 376 | memcpy(gbuf->transfer_buffer, data, msg_size); |
| 377 | gbuf->actual_length = msg_size; |
| 378 | |
| 379 | /* XXX And now we let a work queue handle the rest */ |
| 380 | } |