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/module.h> 13 #include <linux/of.h> 14 #include <linux/of_platform.h> 15 #include <linux/platform_device.h> 16 #include <linux/slab.h> 17 #include <soc/bcm2835/raspberrypi-firmware.h> 18 19 #define MBOX_MSG(chan, data28) (((data28) & ~0xf) | ((chan) & 0xf)) 20 #define MBOX_CHAN(msg) ((msg) & 0xf) 21 #define MBOX_DATA28(msg) ((msg) & ~0xf) 22 #define MBOX_CHAN_PROPERTY 8 23 24 static struct platform_device *rpi_hwmon; 25 static struct platform_device *rpi_clk; 26 27 struct rpi_firmware { 28 struct mbox_client cl; 29 struct mbox_chan *chan; /* The property channel. */ 30 struct completion c; 31 u32 enabled; 32 33 struct kref consumers; 34 }; 35 36 static DEFINE_MUTEX(transaction_lock); 37 38 static void response_callback(struct mbox_client *cl, void *msg) 39 { 40 struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl); 41 complete(&fw->c); 42 } 43 44 /* 45 * Sends a request to the firmware through the BCM2835 mailbox driver, 46 * and synchronously waits for the reply. 47 */ 48 static int 49 rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data) 50 { 51 u32 message = MBOX_MSG(chan, data); 52 int ret; 53 54 WARN_ON(data & 0xf); 55 56 mutex_lock(&transaction_lock); 57 reinit_completion(&fw->c); 58 ret = mbox_send_message(fw->chan, &message); 59 if (ret >= 0) { 60 if (wait_for_completion_timeout(&fw->c, HZ)) { 61 ret = 0; 62 } else { 63 ret = -ETIMEDOUT; 64 WARN_ONCE(1, "Firmware transaction timeout"); 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->cl.dev, PAGE_ALIGN(size), &bus_addr, 101 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 } 128 129 dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr); 130 131 return ret; 132 } 133 EXPORT_SYMBOL_GPL(rpi_firmware_property_list); 134 135 /** 136 * rpi_firmware_property - Submit single firmware property 137 * @fw: Pointer to firmware structure from rpi_firmware_get(). 138 * @tag: One of enum_mbox_property_tag. 139 * @tag_data: Tag data buffer. 140 * @buf_size: Buffer size. 141 * 142 * Submits a single tag to the VPU firmware through the mailbox 143 * property interface. 144 * 145 * This is a convenience wrapper around 146 * rpi_firmware_property_list() to avoid some of the 147 * boilerplate in property calls. 148 */ 149 int rpi_firmware_property(struct rpi_firmware *fw, 150 u32 tag, void *tag_data, size_t buf_size) 151 { 152 struct rpi_firmware_property_tag_header *header; 153 int ret; 154 155 /* Some mailboxes can use over 1k bytes. Rather than checking 156 * size and using stack or kmalloc depending on requirements, 157 * just use kmalloc. Mailboxes don't get called enough to worry 158 * too much about the time taken in the allocation. 159 */ 160 void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL); 161 162 if (!data) 163 return -ENOMEM; 164 165 header = data; 166 header->tag = tag; 167 header->buf_size = buf_size; 168 header->req_resp_size = 0; 169 memcpy(data + sizeof(*header), tag_data, buf_size); 170 171 ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header)); 172 173 memcpy(tag_data, data + sizeof(*header), buf_size); 174 175 kfree(data); 176 177 return ret; 178 } 179 EXPORT_SYMBOL_GPL(rpi_firmware_property); 180 181 static void 182 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw) 183 { 184 time64_t date_and_time; 185 u32 packet; 186 int ret = rpi_firmware_property(fw, 187 RPI_FIRMWARE_GET_FIRMWARE_REVISION, 188 &packet, sizeof(packet)); 189 190 if (ret) 191 return; 192 193 /* This is not compatible with y2038 */ 194 date_and_time = packet; 195 dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &date_and_time); 196 } 197 198 static void 199 rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw) 200 { 201 u32 packet; 202 int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED, 203 &packet, sizeof(packet)); 204 205 if (ret) 206 return; 207 208 rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon", 209 -1, NULL, 0); 210 } 211 212 static void rpi_register_clk_driver(struct device *dev) 213 { 214 struct device_node *firmware; 215 216 /* 217 * Earlier DTs don't have a node for the firmware clocks but 218 * rely on us creating a platform device by hand. If we do 219 * have a node for the firmware clocks, just bail out here. 220 */ 221 firmware = of_get_compatible_child(dev->of_node, 222 "raspberrypi,firmware-clocks"); 223 if (firmware) { 224 of_node_put(firmware); 225 return; 226 } 227 228 rpi_clk = platform_device_register_data(dev, "raspberrypi-clk", 229 -1, NULL, 0); 230 } 231 232 unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw, unsigned int id) 233 { 234 struct rpi_firmware_clk_rate_request msg = 235 RPI_FIRMWARE_CLK_RATE_REQUEST(id); 236 int ret; 237 238 ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_MAX_CLOCK_RATE, 239 &msg, sizeof(msg)); 240 if (ret) 241 /* 242 * If our firmware doesn't support that operation, or fails, we 243 * assume the maximum clock rate is absolute maximum we can 244 * store over our type. 245 */ 246 return UINT_MAX; 247 248 return le32_to_cpu(msg.rate); 249 } 250 EXPORT_SYMBOL_GPL(rpi_firmware_clk_get_max_rate); 251 252 static void rpi_firmware_delete(struct kref *kref) 253 { 254 struct rpi_firmware *fw = container_of(kref, struct rpi_firmware, 255 consumers); 256 257 mbox_free_channel(fw->chan); 258 kfree(fw); 259 } 260 261 void rpi_firmware_put(struct rpi_firmware *fw) 262 { 263 kref_put(&fw->consumers, rpi_firmware_delete); 264 } 265 EXPORT_SYMBOL_GPL(rpi_firmware_put); 266 267 static void devm_rpi_firmware_put(void *data) 268 { 269 struct rpi_firmware *fw = data; 270 271 rpi_firmware_put(fw); 272 } 273 274 static int rpi_firmware_probe(struct platform_device *pdev) 275 { 276 struct device *dev = &pdev->dev; 277 struct rpi_firmware *fw; 278 279 /* 280 * Memory will be freed by rpi_firmware_delete() once all users have 281 * released their firmware handles. Don't use devm_kzalloc() here. 282 */ 283 fw = kzalloc(sizeof(*fw), GFP_KERNEL); 284 if (!fw) 285 return -ENOMEM; 286 287 fw->cl.dev = dev; 288 fw->cl.rx_callback = response_callback; 289 fw->cl.tx_block = true; 290 291 fw->chan = mbox_request_channel(&fw->cl, 0); 292 if (IS_ERR(fw->chan)) { 293 int ret = PTR_ERR(fw->chan); 294 kfree(fw); 295 return dev_err_probe(dev, ret, "Failed to get mbox channel\n"); 296 } 297 298 init_completion(&fw->c); 299 kref_init(&fw->consumers); 300 301 platform_set_drvdata(pdev, fw); 302 303 rpi_firmware_print_firmware_revision(fw); 304 rpi_register_hwmon_driver(dev, fw); 305 rpi_register_clk_driver(dev); 306 307 return 0; 308 } 309 310 static void rpi_firmware_shutdown(struct platform_device *pdev) 311 { 312 struct rpi_firmware *fw = platform_get_drvdata(pdev); 313 314 if (!fw) 315 return; 316 317 rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0); 318 } 319 320 static void rpi_firmware_remove(struct platform_device *pdev) 321 { 322 struct rpi_firmware *fw = platform_get_drvdata(pdev); 323 324 platform_device_unregister(rpi_hwmon); 325 rpi_hwmon = NULL; 326 platform_device_unregister(rpi_clk); 327 rpi_clk = NULL; 328 329 rpi_firmware_put(fw); 330 } 331 332 static const struct of_device_id rpi_firmware_of_match[] = { 333 { .compatible = "raspberrypi,bcm2835-firmware", }, 334 {}, 335 }; 336 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match); 337 338 struct device_node *rpi_firmware_find_node(void) 339 { 340 return of_find_matching_node(NULL, rpi_firmware_of_match); 341 } 342 EXPORT_SYMBOL_GPL(rpi_firmware_find_node); 343 344 /** 345 * rpi_firmware_get - Get pointer to rpi_firmware structure. 346 * @firmware_node: Pointer to the firmware Device Tree node. 347 * 348 * The reference to rpi_firmware has to be released with rpi_firmware_put(). 349 * 350 * Returns NULL is the firmware device is not ready. 351 */ 352 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node) 353 { 354 struct platform_device *pdev = of_find_device_by_node(firmware_node); 355 struct rpi_firmware *fw; 356 357 if (!pdev) 358 return NULL; 359 360 fw = platform_get_drvdata(pdev); 361 if (!fw) 362 goto err_put_device; 363 364 if (!kref_get_unless_zero(&fw->consumers)) 365 goto err_put_device; 366 367 put_device(&pdev->dev); 368 369 return fw; 370 371 err_put_device: 372 put_device(&pdev->dev); 373 return NULL; 374 } 375 EXPORT_SYMBOL_GPL(rpi_firmware_get); 376 377 /** 378 * devm_rpi_firmware_get - Get pointer to rpi_firmware structure. 379 * @dev: The firmware device structure 380 * @firmware_node: Pointer to the firmware Device Tree node. 381 * 382 * Returns NULL is the firmware device is not ready. 383 */ 384 struct rpi_firmware *devm_rpi_firmware_get(struct device *dev, 385 struct device_node *firmware_node) 386 { 387 struct rpi_firmware *fw; 388 389 fw = rpi_firmware_get(firmware_node); 390 if (!fw) 391 return NULL; 392 393 if (devm_add_action_or_reset(dev, devm_rpi_firmware_put, fw)) 394 return NULL; 395 396 return fw; 397 } 398 EXPORT_SYMBOL_GPL(devm_rpi_firmware_get); 399 400 static struct platform_driver rpi_firmware_driver = { 401 .driver = { 402 .name = "raspberrypi-firmware", 403 .of_match_table = rpi_firmware_of_match, 404 }, 405 .probe = rpi_firmware_probe, 406 .shutdown = rpi_firmware_shutdown, 407 .remove_new = rpi_firmware_remove, 408 }; 409 module_platform_driver(rpi_firmware_driver); 410 411 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>"); 412 MODULE_DESCRIPTION("Raspberry Pi firmware driver"); 413 MODULE_LICENSE("GPL v2"); 414