drivers/firmware/raspberrypi.c

   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         = 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");