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                         WARN_ONCE(1, "Firmware transaction timeout");
  66                 }
  67         } else {
  68                 dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
  69         }
  70         mutex_unlock(&transaction_lock);
  71
  72         return ret;
  73 }
  74
  75 /**
  76  * rpi_firmware_property_list - Submit firmware property list
  77  * @fw:         Pointer to firmware structure from rpi_firmware_get().
  78  * @data:       Buffer holding tags.
  79  * @tag_size:   Size of tags buffer.
  80  *
  81  * Submits a set of concatenated tags to the VPU firmware through the
  82  * mailbox property interface.
  83  *
  84  * The buffer header and the ending tag are added by this function and
  85  * don't need to be supplied, just the actual tags for your operation.
  86  * See struct rpi_firmware_property_tag_header for the per-tag
  87  * structure.
  88  */
  89 int rpi_firmware_property_list(struct rpi_firmware *fw,
  90                                void *data, size_t tag_size)
  91 {
  92         size_t size = tag_size + 12;
  93         u32 *buf;
  94         dma_addr_t bus_addr;
  95         int ret;
  96
  97         /* Packets are processed a dword at a time. */
  98         if (size & 3)
  99                 return -EINVAL;
 100
 101         buf = dma_alloc_coherent(fw->chan->mbox->dev, PAGE_ALIGN(size),
 102                                  &bus_addr, GFP_ATOMIC);
 103         if (!buf)
 104                 return -ENOMEM;
 105
 106         /* The firmware will error out without parsing in this case. */
 107         WARN_ON(size >= 1024 * 1024);
 108
 109         buf[0] = size;
 110         buf[1] = RPI_FIRMWARE_STATUS_REQUEST;
 111         memcpy(&buf[2], data, tag_size);
 112         buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END;
 113         wmb();
 114
 115         ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr);
 116
 117         rmb();
 118         memcpy(data, &buf[2], tag_size);
 119         if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) {
 120                 /*
 121                  * The tag name here might not be the one causing the
 122                  * error, if there were multiple tags in the request.
 123                  * But single-tag is the most common, so go with it.
 124                  */
 125                 dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",
 126                         buf[2], buf[1]);
 127                 ret = -EINVAL;
 128         }
 129
 130         dma_free_coherent(fw->chan->mbox->dev, PAGE_ALIGN(size), buf, bus_addr);
 131
 132         return ret;
 133 }
 134 EXPORT_SYMBOL_GPL(rpi_firmware_property_list);
 135
 136 /**
 137  * rpi_firmware_property - Submit single firmware property
 138  * @fw:         Pointer to firmware structure from rpi_firmware_get().
 139  * @tag:        One of enum_mbox_property_tag.
 140  * @tag_data:   Tag data buffer.
 141  * @buf_size:   Buffer size.
 142  *
 143  * Submits a single tag to the VPU firmware through the mailbox
 144  * property interface.
 145  *
 146  * This is a convenience wrapper around
 147  * rpi_firmware_property_list() to avoid some of the
 148  * boilerplate in property calls.
 149  */
 150 int rpi_firmware_property(struct rpi_firmware *fw,
 151                           u32 tag, void *tag_data, size_t buf_size)
 152 {
 153         struct rpi_firmware_property_tag_header *header;
 154         int ret;
 155
 156         /* Some mailboxes can use over 1k bytes. Rather than checking
 157          * size and using stack or kmalloc depending on requirements,
 158          * just use kmalloc. Mailboxes don't get called enough to worry
 159          * too much about the time taken in the allocation.
 160          */
 161         void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL);
 162
 163         if (!data)
 164                 return -ENOMEM;
 165
 166         header = data;
 167         header->tag = tag;
 168         header->buf_size = buf_size;
 169         header->req_resp_size = 0;
 170         memcpy(data + sizeof(*header), tag_data, buf_size);
 171
 172         ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header));
 173
 174         memcpy(tag_data, data + sizeof(*header), buf_size);
 175
 176         kfree(data);
 177
 178         return ret;
 179 }
 180 EXPORT_SYMBOL_GPL(rpi_firmware_property);
 181
 182 static void
 183 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
 184 {
 185         time64_t date_and_time;
 186         u32 packet;
 187         int ret = rpi_firmware_property(fw,
 188                                         RPI_FIRMWARE_GET_FIRMWARE_REVISION,
 189                                         &packet, sizeof(packet));
 190
 191         if (ret)
 192                 return;
 193
 194         /* This is not compatible with y2038 */
 195         date_and_time = packet;
 196         dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &date_and_time);
 197 }
 198
 199 static void
 200 rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw)
 201 {
 202         u32 packet;
 203         int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED,
 204                                         &packet, sizeof(packet));
 205
 206         if (ret)
 207                 return;
 208
 209         rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon",
 210                                                   -1, NULL, 0);
 211 }
 212
 213 static void rpi_register_clk_driver(struct device *dev)
 214 {
 215         struct device_node *firmware;
 216
 217         /*
 218          * Earlier DTs don't have a node for the firmware clocks but
 219          * rely on us creating a platform device by hand. If we do
 220          * have a node for the firmware clocks, just bail out here.
 221          */
 222         firmware = of_get_compatible_child(dev->of_node,
 223                                            "raspberrypi,firmware-clocks");
 224         if (firmware) {
 225                 of_node_put(firmware);
 226                 return;
 227         }
 228
 229         rpi_clk = platform_device_register_data(dev, "raspberrypi-clk",
 230                                                 -1, NULL, 0);
 231 }
 232
 233 unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw, unsigned int id)
 234 {
 235         struct rpi_firmware_clk_rate_request msg =
 236                 RPI_FIRMWARE_CLK_RATE_REQUEST(id);
 237         int ret;
 238
 239         ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_MAX_CLOCK_RATE,
 240                                     &msg, sizeof(msg));
 241         if (ret)
 242                 /*
 243                  * If our firmware doesn't support that operation, or fails, we
 244                  * assume the maximum clock rate is absolute maximum we can
 245                  * store over our type.
 246                  */
 247                  return UINT_MAX;
 248
 249         return le32_to_cpu(msg.rate);
 250 }
 251 EXPORT_SYMBOL_GPL(rpi_firmware_clk_get_max_rate);
 252
 253 static void rpi_firmware_delete(struct kref *kref)
 254 {
 255         struct rpi_firmware *fw = container_of(kref, struct rpi_firmware,
 256                                                consumers);
 257
 258         mbox_free_channel(fw->chan);
 259         kfree(fw);
 260 }
 261
 262 void rpi_firmware_put(struct rpi_firmware *fw)
 263 {
 264         kref_put(&fw->consumers, rpi_firmware_delete);
 265 }
 266 EXPORT_SYMBOL_GPL(rpi_firmware_put);
 267
 268 static void devm_rpi_firmware_put(void *data)
 269 {
 270         struct rpi_firmware *fw = data;
 271
 272         rpi_firmware_put(fw);
 273 }
 274
 275 static int rpi_firmware_probe(struct platform_device *pdev)
 276 {
 277         struct device *dev = &pdev->dev;
 278         struct rpi_firmware *fw;
 279
 280         /*
 281          * Memory will be freed by rpi_firmware_delete() once all users have
 282          * released their firmware handles. Don't use devm_kzalloc() here.
 283          */
 284         fw = kzalloc(sizeof(*fw), GFP_KERNEL);
 285         if (!fw)
 286                 return -ENOMEM;
 287
 288         fw->cl.dev = dev;
 289         fw->cl.rx_callback = response_callback;
 290         fw->cl.tx_block = true;
 291
 292         fw->chan = mbox_request_channel(&fw->cl, 0);
 293         if (IS_ERR(fw->chan)) {
 294                 int ret = PTR_ERR(fw->chan);
 295                 kfree(fw);
 296                 return dev_err_probe(dev, ret, "Failed to get mbox channel\n");
 297         }
 298
 299         init_completion(&fw->c);
 300         kref_init(&fw->consumers);
 301
 302         platform_set_drvdata(pdev, fw);
 303
 304         rpi_firmware_print_firmware_revision(fw);
 305         rpi_register_hwmon_driver(dev, fw);
 306         rpi_register_clk_driver(dev);
 307
 308         return 0;
 309 }
 310
 311 static void rpi_firmware_shutdown(struct platform_device *pdev)
 312 {
 313         struct rpi_firmware *fw = platform_get_drvdata(pdev);
 314
 315         if (!fw)
 316                 return;
 317
 318         rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);
 319 }
 320
 321 static void rpi_firmware_remove(struct platform_device *pdev)
 322 {
 323         struct rpi_firmware *fw = platform_get_drvdata(pdev);
 324
 325         platform_device_unregister(rpi_hwmon);
 326         rpi_hwmon = NULL;
 327         platform_device_unregister(rpi_clk);
 328         rpi_clk = NULL;
 329
 330         rpi_firmware_put(fw);
 331 }
 332
 333 static const struct of_device_id rpi_firmware_of_match[] = {
 334         { .compatible = "raspberrypi,bcm2835-firmware", },
 335         {},
 336 };
 337 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
 338
 339 struct device_node *rpi_firmware_find_node(void)
 340 {
 341         return of_find_matching_node(NULL, rpi_firmware_of_match);
 342 }
 343 EXPORT_SYMBOL_GPL(rpi_firmware_find_node);
 344
 345 /**
 346  * rpi_firmware_get - Get pointer to rpi_firmware structure.
 347  * @firmware_node:    Pointer to the firmware Device Tree node.
 348  *
 349  * The reference to rpi_firmware has to be released with rpi_firmware_put().
 350  *
 351  * Returns NULL is the firmware device is not ready.
 352  */
 353 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
 354 {
 355         struct platform_device *pdev = of_find_device_by_node(firmware_node);
 356         struct rpi_firmware *fw;
 357
 358         if (!pdev)
 359                 return NULL;
 360
 361         fw = platform_get_drvdata(pdev);
 362         if (!fw)
 363                 goto err_put_device;
 364
 365         if (!kref_get_unless_zero(&fw->consumers))
 366                 goto err_put_device;
 367
 368         put_device(&pdev->dev);
 369
 370         return fw;
 371
 372 err_put_device:
 373         put_device(&pdev->dev);
 374         return NULL;
 375 }
 376 EXPORT_SYMBOL_GPL(rpi_firmware_get);
 377
 378 /**
 379  * devm_rpi_firmware_get - Get pointer to rpi_firmware structure.
 380  * @dev:              The firmware device 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_new     = 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");