drivers/firmware/raspberrypi.c

   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/mailbox_client.h>
  11 #include <linux/module.h>
  12 #include <linux/of_platform.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/slab.h>
  15 #include <linux/pci.h>
  16 #include <linux/delay.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 #define VL805_PCI_CONFIG_VERSION_OFFSET         0x50
  25
  26 static struct platform_device *rpi_hwmon;
  27 static struct platform_device *rpi_clk;
  28
  29 struct rpi_firmware {
  30         struct mbox_client cl;
  31         struct mbox_chan *chan; /* The property channel. */
  32         struct completion c;
  33         u32 enabled;
  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         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         dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &packet);
 193 }
 194
 195 static void
 196 rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw)
 197 {
 198         u32 packet;
 199         int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED,
 200                                         &packet, sizeof(packet));
 201
 202         if (ret)
 203                 return;
 204
 205         rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon",
 206                                                   -1, NULL, 0);
 207 }
 208
 209 static void rpi_register_clk_driver(struct device *dev)
 210 {
 211         rpi_clk = platform_device_register_data(dev, "raspberrypi-clk",
 212                                                 -1, NULL, 0);
 213 }
 214
 215 static int rpi_firmware_probe(struct platform_device *pdev)
 216 {
 217         struct device *dev = &pdev->dev;
 218         struct rpi_firmware *fw;
 219
 220         fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL);
 221         if (!fw)
 222                 return -ENOMEM;
 223
 224         fw->cl.dev = dev;
 225         fw->cl.rx_callback = response_callback;
 226         fw->cl.tx_block = true;
 227
 228         fw->chan = mbox_request_channel(&fw->cl, 0);
 229         if (IS_ERR(fw->chan)) {
 230                 int ret = PTR_ERR(fw->chan);
 231                 if (ret != -EPROBE_DEFER)
 232                         dev_err(dev, "Failed to get mbox channel: %d\n", ret);
 233                 return ret;
 234         }
 235
 236         init_completion(&fw->c);
 237
 238         platform_set_drvdata(pdev, fw);
 239
 240         rpi_firmware_print_firmware_revision(fw);
 241         rpi_register_hwmon_driver(dev, fw);
 242         rpi_register_clk_driver(dev);
 243
 244         return 0;
 245 }
 246
 247 static void rpi_firmware_shutdown(struct platform_device *pdev)
 248 {
 249         struct rpi_firmware *fw = platform_get_drvdata(pdev);
 250
 251         if (!fw)
 252                 return;
 253
 254         rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);
 255 }
 256
 257 static int rpi_firmware_remove(struct platform_device *pdev)
 258 {
 259         struct rpi_firmware *fw = platform_get_drvdata(pdev);
 260
 261         platform_device_unregister(rpi_hwmon);
 262         rpi_hwmon = NULL;
 263         platform_device_unregister(rpi_clk);
 264         rpi_clk = NULL;
 265         mbox_free_channel(fw->chan);
 266
 267         return 0;
 268 }
 269
 270 /**
 271  * rpi_firmware_get - Get pointer to rpi_firmware structure.
 272  * @firmware_node:    Pointer to the firmware Device Tree node.
 273  *
 274  * Returns NULL is the firmware device is not ready.
 275  */
 276 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
 277 {
 278         struct platform_device *pdev = of_find_device_by_node(firmware_node);
 279
 280         if (!pdev)
 281                 return NULL;
 282
 283         return platform_get_drvdata(pdev);
 284 }
 285 EXPORT_SYMBOL_GPL(rpi_firmware_get);
 286
 287 /*
 288  * The Raspberry Pi 4 gets its USB functionality from VL805, a PCIe chip that
 289  * implements xHCI. After a PCI reset, VL805's firmware may either be loaded
 290  * directly from an EEPROM or, if not present, by the SoC's co-processor,
 291  * VideoCore. RPi4's VideoCore OS contains both the non public firmware load
 292  * logic and the VL805 firmware blob. This function triggers the aforementioned
 293  * process.
 294  */
 295 int rpi_firmware_init_vl805(struct pci_dev *pdev)
 296 {
 297         struct device_node *fw_np;
 298         struct rpi_firmware *fw;
 299         u32 dev_addr, version;
 300         int ret;
 301
 302         fw_np = of_find_compatible_node(NULL, NULL,
 303                                         "raspberrypi,bcm2835-firmware");
 304         if (!fw_np)
 305                 return 0;
 306
 307         fw = rpi_firmware_get(fw_np);
 308         of_node_put(fw_np);
 309         if (!fw)
 310                 return -ENODEV;
 311
 312         /*
 313          * Make sure we don't trigger a firmware load unnecessarily.
 314          *
 315          * If something went wrong with PCI, this whole exercise would be
 316          * futile as VideoCore expects from us a configured PCI bus. Just take
 317          * the faulty version (likely ~0) and let xHCI's registration fail
 318          * further down the line.
 319          */
 320         pci_read_config_dword(pdev, VL805_PCI_CONFIG_VERSION_OFFSET, &version);
 321         if (version)
 322                 goto exit;
 323
 324         dev_addr = pdev->bus->number << 20 | PCI_SLOT(pdev->devfn) << 15 |
 325                    PCI_FUNC(pdev->devfn) << 12;
 326
 327         ret = rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_XHCI_RESET,
 328                                     &dev_addr, sizeof(dev_addr));
 329         if (ret)
 330                 return ret;
 331
 332         /* Wait for vl805 to startup */
 333         usleep_range(200, 1000);
 334
 335         pci_read_config_dword(pdev, VL805_PCI_CONFIG_VERSION_OFFSET,
 336                               &version);
 337 exit:
 338         pci_info(pdev, "VL805 firmware version %08x\n", version);
 339
 340         return 0;
 341 }
 342 EXPORT_SYMBOL_GPL(rpi_firmware_init_vl805);
 343
 344 static const struct of_device_id rpi_firmware_of_match[] = {
 345         { .compatible = "raspberrypi,bcm2835-firmware", },
 346         {},
 347 };
 348 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
 349
 350 static struct platform_driver rpi_firmware_driver = {
 351         .driver = {
 352                 .name = "raspberrypi-firmware",
 353                 .of_match_table = rpi_firmware_of_match,
 354         },
 355         .probe          = rpi_firmware_probe,
 356         .shutdown       = rpi_firmware_shutdown,
 357         .remove         = rpi_firmware_remove,
 358 };
 359 module_platform_driver(rpi_firmware_driver);
 360
 361 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
 362 MODULE_DESCRIPTION("Raspberry Pi firmware driver");
 363 MODULE_LICENSE("GPL v2");