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_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
  23 static struct platform_device *rpi_hwmon;
  24 static struct platform_device *rpi_clk;
  25
  26 struct 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
  35 static DEFINE_MUTEX(transaction_lock);
  36
  37 static 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  */
  47 static int
  48 rpi_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  */
  87 int 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 }
 132 EXPORT_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  */
 148 int 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 }
 178 EXPORT_SYMBOL_GPL(rpi_firmware_property);
 179
 180 static void
 181 rpi_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
 197 static void
 198 rpi_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
 211 static 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
 231 static 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
 240 void rpi_firmware_put(struct rpi_firmware *fw)
 241 {
 242         kref_put(&fw->consumers, rpi_firmware_delete);
 243 }
 244 EXPORT_SYMBOL_GPL(rpi_firmware_put);
 245
 246 static void devm_rpi_firmware_put(void *data)
 247 {
 248         struct rpi_firmware *fw = data;
 249
 250         rpi_firmware_put(fw);
 251 }
 252
 253 static 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                 return ret;
 276         }
 277
 278         init_completion(&fw->c);
 279         kref_init(&fw->consumers);
 280
 281         platform_set_drvdata(pdev, fw);
 282
 283         rpi_firmware_print_firmware_revision(fw);
 284         rpi_register_hwmon_driver(dev, fw);
 285         rpi_register_clk_driver(dev);
 286
 287         return 0;
 288 }
 289
 290 static void rpi_firmware_shutdown(struct platform_device *pdev)
 291 {
 292         struct rpi_firmware *fw = platform_get_drvdata(pdev);
 293
 294         if (!fw)
 295                 return;
 296
 297         rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);
 298 }
 299
 300 static int rpi_firmware_remove(struct platform_device *pdev)
 301 {
 302         struct rpi_firmware *fw = platform_get_drvdata(pdev);
 303
 304         platform_device_unregister(rpi_hwmon);
 305         rpi_hwmon = NULL;
 306         platform_device_unregister(rpi_clk);
 307         rpi_clk = NULL;
 308
 309         rpi_firmware_put(fw);
 310
 311         return 0;
 312 }
 313
 314 /**
 315  * rpi_firmware_get - Get pointer to rpi_firmware structure.
 316  * @firmware_node:    Pointer to the firmware Device Tree node.
 317  *
 318  * The reference to rpi_firmware has to be released with rpi_firmware_put().
 319  *
 320  * Returns NULL is the firmware device is not ready.
 321  */
 322 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
 323 {
 324         struct platform_device *pdev = of_find_device_by_node(firmware_node);
 325         struct rpi_firmware *fw;
 326
 327         if (!pdev)
 328                 return NULL;
 329
 330         fw = platform_get_drvdata(pdev);
 331         if (!fw)
 332                 goto err_put_device;
 333
 334         if (!kref_get_unless_zero(&fw->consumers))
 335                 goto err_put_device;
 336
 337         put_device(&pdev->dev);
 338
 339         return fw;
 340
 341 err_put_device:
 342         put_device(&pdev->dev);
 343         return NULL;
 344 }
 345 EXPORT_SYMBOL_GPL(rpi_firmware_get);
 346
 347 /**
 348  * devm_rpi_firmware_get - Get pointer to rpi_firmware structure.
 349  * @firmware_node:    Pointer to the firmware Device Tree node.
 350  *
 351  * Returns NULL is the firmware device is not ready.
 352  */
 353 struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
 354                                            struct device_node *firmware_node)
 355 {
 356         struct rpi_firmware *fw;
 357
 358         fw = rpi_firmware_get(firmware_node);
 359         if (!fw)
 360                 return NULL;
 361
 362         if (devm_add_action_or_reset(dev, devm_rpi_firmware_put, fw))
 363                 return NULL;
 364
 365         return fw;
 366 }
 367 EXPORT_SYMBOL_GPL(devm_rpi_firmware_get);
 368
 369 static const struct of_device_id rpi_firmware_of_match[] = {
 370         { .compatible = "raspberrypi,bcm2835-firmware", },
 371         {},
 372 };
 373 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
 374
 375 static struct platform_driver rpi_firmware_driver = {
 376         .driver = {
 377                 .name = "raspberrypi-firmware",
 378                 .of_match_table = rpi_firmware_of_match,
 379         },
 380         .probe          = rpi_firmware_probe,
 381         .shutdown       = rpi_firmware_shutdown,
 382         .remove         = rpi_firmware_remove,
 383 };
 384 module_platform_driver(rpi_firmware_driver);
 385
 386 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
 387 MODULE_DESCRIPTION("Raspberry Pi firmware driver");
 388 MODULE_LICENSE("GPL v2");