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