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/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 int 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         return 0;
 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  * @firmware_node:    Pointer to the firmware Device Tree node.
 382  *
 383  * Returns NULL is the firmware device is not ready.
 384  */
 385 struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
 386                                            struct device_node *firmware_node)
 387 {
 388         struct rpi_firmware *fw;
 389
 390         fw = rpi_firmware_get(firmware_node);
 391         if (!fw)
 392                 return NULL;
 393
 394         if (devm_add_action_or_reset(dev, devm_rpi_firmware_put, fw))
 395                 return NULL;
 396
 397         return fw;
 398 }
 399 EXPORT_SYMBOL_GPL(devm_rpi_firmware_get);
 400
 401 static struct platform_driver rpi_firmware_driver = {
 402         .driver = {
 403                 .name = "raspberrypi-firmware",
 404                 .of_match_table = rpi_firmware_of_match,
 405         },
 406         .probe          = rpi_firmware_probe,
 407         .shutdown       = rpi_firmware_shutdown,
 408         .remove         = rpi_firmware_remove,
 409 };
 410 module_platform_driver(rpi_firmware_driver);
 411
 412 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
 413 MODULE_DESCRIPTION("Raspberry Pi firmware driver");
 414 MODULE_LICENSE("GPL v2");