1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Defines interfaces for interacting with the Raspberry Pi firmware's 4 * property channel. 5 * 6 * Copyright © 2015 Broadcom 7 */ 8 9 #include <linux/dma-mapping.h> 10 #include <linux/kref.h> 11 #include <linux/mailbox_client.h> 12 #include <linux/mailbox_controller.h> 13 #include <linux/module.h> 14 #include <linux/of.h> 15 #include <linux/of_platform.h> 16 #include <linux/platform_device.h> 17 #include <linux/slab.h> 18 #include <soc/bcm2835/raspberrypi-firmware.h> 19 20 #define MBOX_MSG(chan, data28) (((data28) & ~0xf) | ((chan) & 0xf)) 21 #define MBOX_CHAN(msg) ((msg) & 0xf) 22 #define MBOX_DATA28(msg) ((msg) & ~0xf) 23 #define MBOX_CHAN_PROPERTY 8 24 25 static struct platform_device *rpi_hwmon; 26 static struct platform_device *rpi_clk; 27 28 struct rpi_firmware { 29 struct mbox_client cl; 30 struct mbox_chan *chan; /* The property channel. */ 31 struct completion c; 32 u32 enabled; 33 34 struct kref consumers; 35 }; 36 37 static DEFINE_MUTEX(transaction_lock); 38 39 static void response_callback(struct mbox_client *cl, void *msg) 40 { 41 struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl); 42 complete(&fw->c); 43 } 44 45 /* 46 * Sends a request to the firmware through the BCM2835 mailbox driver, 47 * and synchronously waits for the reply. 48 */ 49 static int 50 rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data) 51 { 52 u32 message = MBOX_MSG(chan, data); 53 int ret; 54 55 WARN_ON(data & 0xf); 56 57 mutex_lock(&transaction_lock); 58 reinit_completion(&fw->c); 59 ret = mbox_send_message(fw->chan, &message); 60 if (ret >= 0) { 61 if (wait_for_completion_timeout(&fw->c, HZ)) { 62 ret = 0; 63 } else { 64 ret = -ETIMEDOUT; 65 } 66 } else { 67 dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret); 68 } 69 mutex_unlock(&transaction_lock); 70 71 return ret; 72 } 73 74 /** 75 * rpi_firmware_property_list - Submit firmware property list 76 * @fw: Pointer to firmware structure from rpi_firmware_get(). 77 * @data: Buffer holding tags. 78 * @tag_size: Size of tags buffer. 79 * 80 * Submits a set of concatenated tags to the VPU firmware through the 81 * mailbox property interface. 82 * 83 * The buffer header and the ending tag are added by this function and 84 * don't need to be supplied, just the actual tags for your operation. 85 * See struct rpi_firmware_property_tag_header for the per-tag 86 * structure. 87 */ 88 int rpi_firmware_property_list(struct rpi_firmware *fw, 89 void *data, size_t tag_size) 90 { 91 size_t size = tag_size + 12; 92 u32 *buf; 93 dma_addr_t bus_addr; 94 int ret; 95 96 /* Packets are processed a dword at a time. */ 97 if (size & 3) 98 return -EINVAL; 99 100 buf = dma_alloc_coherent(fw->chan->mbox->dev, PAGE_ALIGN(size), 101 &bus_addr, GFP_ATOMIC); 102 if (!buf) 103 return -ENOMEM; 104 105 /* The firmware will error out without parsing in this case. */ 106 WARN_ON(size >= 1024 * 1024); 107 108 buf[0] = size; 109 buf[1] = RPI_FIRMWARE_STATUS_REQUEST; 110 memcpy(&buf[2], data, tag_size); 111 buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END; 112 wmb(); 113 114 ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr); 115 116 rmb(); 117 memcpy(data, &buf[2], tag_size); 118 if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) { 119 /* 120 * The tag name here might not be the one causing the 121 * error, if there were multiple tags in the request. 122 * But single-tag is the most common, so go with it. 123 */ 124 dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n", 125 buf[2], buf[1]); 126 ret = -EINVAL; 127 } else if (ret == -ETIMEDOUT) { 128 WARN_ONCE(1, "Firmware transaction 0x%08x timeout", buf[2]); 129 } 130 131 dma_free_coherent(fw->chan->mbox->dev, PAGE_ALIGN(size), buf, bus_addr); 132 133 return ret; 134 } 135 EXPORT_SYMBOL_GPL(rpi_firmware_property_list); 136 137 /** 138 * rpi_firmware_property - Submit single firmware property 139 * @fw: Pointer to firmware structure from rpi_firmware_get(). 140 * @tag: One of enum_mbox_property_tag. 141 * @tag_data: Tag data buffer. 142 * @buf_size: Buffer size. 143 * 144 * Submits a single tag to the VPU firmware through the mailbox 145 * property interface. 146 * 147 * This is a convenience wrapper around 148 * rpi_firmware_property_list() to avoid some of the 149 * boilerplate in property calls. 150 */ 151 int rpi_firmware_property(struct rpi_firmware *fw, 152 u32 tag, void *tag_data, size_t buf_size) 153 { 154 struct rpi_firmware_property_tag_header *header; 155 int ret; 156 157 /* Some mailboxes can use over 1k bytes. Rather than checking 158 * size and using stack or kmalloc depending on requirements, 159 * just use kmalloc. Mailboxes don't get called enough to worry 160 * too much about the time taken in the allocation. 161 */ 162 void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL); 163 164 if (!data) 165 return -ENOMEM; 166 167 header = data; 168 header->tag = tag; 169 header->buf_size = buf_size; 170 header->req_resp_size = 0; 171 memcpy(data + sizeof(*header), tag_data, buf_size); 172 173 ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header)); 174 175 memcpy(tag_data, data + sizeof(*header), buf_size); 176 177 kfree(data); 178 179 return ret; 180 } 181 EXPORT_SYMBOL_GPL(rpi_firmware_property); 182 183 static void 184 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw) 185 { 186 time64_t date_and_time; 187 u32 packet; 188 int ret = rpi_firmware_property(fw, 189 RPI_FIRMWARE_GET_FIRMWARE_REVISION, 190 &packet, sizeof(packet)); 191 192 if (ret) 193 return; 194 195 /* This is not compatible with y2038 */ 196 date_and_time = packet; 197 dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &date_and_time); 198 } 199 200 static void 201 rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw) 202 { 203 u32 packet; 204 int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED, 205 &packet, sizeof(packet)); 206 207 if (ret) 208 return; 209 210 rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon", 211 -1, NULL, 0); 212 } 213 214 static void rpi_register_clk_driver(struct device *dev) 215 { 216 struct device_node *firmware; 217 218 /* 219 * Earlier DTs don't have a node for the firmware clocks but 220 * rely on us creating a platform device by hand. If we do 221 * have a node for the firmware clocks, just bail out here. 222 */ 223 firmware = of_get_compatible_child(dev->of_node, 224 "raspberrypi,firmware-clocks"); 225 if (firmware) { 226 of_node_put(firmware); 227 return; 228 } 229 230 rpi_clk = platform_device_register_data(dev, "raspberrypi-clk", 231 -1, NULL, 0); 232 } 233 234 unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw, unsigned int id) 235 { 236 struct rpi_firmware_clk_rate_request msg = 237 RPI_FIRMWARE_CLK_RATE_REQUEST(id); 238 int ret; 239 240 ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_MAX_CLOCK_RATE, 241 &msg, sizeof(msg)); 242 if (ret) 243 /* 244 * If our firmware doesn't support that operation, or fails, we 245 * assume the maximum clock rate is absolute maximum we can 246 * store over our type. 247 */ 248 return UINT_MAX; 249 250 return le32_to_cpu(msg.rate); 251 } 252 EXPORT_SYMBOL_GPL(rpi_firmware_clk_get_max_rate); 253 254 static void rpi_firmware_delete(struct kref *kref) 255 { 256 struct rpi_firmware *fw = container_of(kref, struct rpi_firmware, 257 consumers); 258 259 mbox_free_channel(fw->chan); 260 kfree(fw); 261 } 262 263 void rpi_firmware_put(struct rpi_firmware *fw) 264 { 265 kref_put(&fw->consumers, rpi_firmware_delete); 266 } 267 EXPORT_SYMBOL_GPL(rpi_firmware_put); 268 269 static void devm_rpi_firmware_put(void *data) 270 { 271 struct rpi_firmware *fw = data; 272 273 rpi_firmware_put(fw); 274 } 275 276 static int rpi_firmware_probe(struct platform_device *pdev) 277 { 278 struct device *dev = &pdev->dev; 279 struct rpi_firmware *fw; 280 281 /* 282 * Memory will be freed by rpi_firmware_delete() once all users have 283 * released their firmware handles. Don't use devm_kzalloc() here. 284 */ 285 fw = kzalloc(sizeof(*fw), GFP_KERNEL); 286 if (!fw) 287 return -ENOMEM; 288 289 fw->cl.dev = dev; 290 fw->cl.rx_callback = response_callback; 291 fw->cl.tx_block = true; 292 293 fw->chan = mbox_request_channel(&fw->cl, 0); 294 if (IS_ERR(fw->chan)) { 295 int ret = PTR_ERR(fw->chan); 296 kfree(fw); 297 return dev_err_probe(dev, ret, "Failed to get mbox channel\n"); 298 } 299 300 init_completion(&fw->c); 301 kref_init(&fw->consumers); 302 303 platform_set_drvdata(pdev, fw); 304 305 rpi_firmware_print_firmware_revision(fw); 306 rpi_register_hwmon_driver(dev, fw); 307 rpi_register_clk_driver(dev); 308 309 return 0; 310 } 311 312 static void rpi_firmware_shutdown(struct platform_device *pdev) 313 { 314 struct rpi_firmware *fw = platform_get_drvdata(pdev); 315 316 if (!fw) 317 return; 318 319 rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0); 320 } 321 322 static void rpi_firmware_remove(struct platform_device *pdev) 323 { 324 struct rpi_firmware *fw = platform_get_drvdata(pdev); 325 326 platform_device_unregister(rpi_hwmon); 327 rpi_hwmon = NULL; 328 platform_device_unregister(rpi_clk); 329 rpi_clk = NULL; 330 331 rpi_firmware_put(fw); 332 } 333 334 static const struct of_device_id rpi_firmware_of_match[] = { 335 { .compatible = "raspberrypi,bcm2835-firmware", }, 336 {}, 337 }; 338 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match); 339 340 struct device_node *rpi_firmware_find_node(void) 341 { 342 return of_find_matching_node(NULL, rpi_firmware_of_match); 343 } 344 EXPORT_SYMBOL_GPL(rpi_firmware_find_node); 345 346 /** 347 * rpi_firmware_get - Get pointer to rpi_firmware structure. 348 * @firmware_node: Pointer to the firmware Device Tree node. 349 * 350 * The reference to rpi_firmware has to be released with rpi_firmware_put(). 351 * 352 * Returns NULL is the firmware device is not ready. 353 */ 354 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node) 355 { 356 struct platform_device *pdev = of_find_device_by_node(firmware_node); 357 struct rpi_firmware *fw; 358 359 if (!pdev) 360 return NULL; 361 362 fw = platform_get_drvdata(pdev); 363 if (!fw) 364 goto err_put_device; 365 366 if (!kref_get_unless_zero(&fw->consumers)) 367 goto err_put_device; 368 369 put_device(&pdev->dev); 370 371 return fw; 372 373 err_put_device: 374 put_device(&pdev->dev); 375 return NULL; 376 } 377 EXPORT_SYMBOL_GPL(rpi_firmware_get); 378 379 /** 380 * devm_rpi_firmware_get - Get pointer to rpi_firmware structure. 381 * @dev: The firmware device structure 382 * @firmware_node: Pointer to the firmware Device Tree node. 383 * 384 * Returns NULL is the firmware device is not ready. 385 */ 386 struct rpi_firmware *devm_rpi_firmware_get(struct device *dev, 387 struct device_node *firmware_node) 388 { 389 struct rpi_firmware *fw; 390 391 fw = rpi_firmware_get(firmware_node); 392 if (!fw) 393 return NULL; 394 395 if (devm_add_action_or_reset(dev, devm_rpi_firmware_put, fw)) 396 return NULL; 397 398 return fw; 399 } 400 EXPORT_SYMBOL_GPL(devm_rpi_firmware_get); 401 402 static struct platform_driver rpi_firmware_driver = { 403 .driver = { 404 .name = "raspberrypi-firmware", 405 .of_match_table = rpi_firmware_of_match, 406 }, 407 .probe = rpi_firmware_probe, 408 .shutdown = rpi_firmware_shutdown, 409 .remove_new = rpi_firmware_remove, 410 }; 411 module_platform_driver(rpi_firmware_driver); 412 413 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>"); 414 MODULE_DESCRIPTION("Raspberry Pi firmware driver"); 415 MODULE_LICENSE("GPL v2"); 416