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/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 <soc/bcm2835/raspberrypi-firmware.h>
  16
  17 #define MBOX_MSG(chan, data28)          (((data28) & ~0xf) | ((chan) & 0xf))
  18 #define MBOX_CHAN(msg)                  ((msg) & 0xf)
  19 #define MBOX_DATA28(msg)                ((msg) & ~0xf)
  20 #define MBOX_CHAN_PROPERTY              8
  21
  22 static struct platform_device *rpi_hwmon;
  23 static struct platform_device *rpi_clk;
  24
  25 struct rpi_firmware {
  26         struct mbox_client cl;
  27         struct mbox_chan *chan; /* The property channel. */
  28         struct completion c;
  29         u32 enabled;
  30 };
  31
  32 static DEFINE_MUTEX(transaction_lock);
  33
  34 static void response_callback(struct mbox_client *cl, void *msg)
  35 {
  36         struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl);
  37         complete(&fw->c);
  38 }
  39
  40 /*
  41  * Sends a request to the firmware through the BCM2835 mailbox driver,
  42  * and synchronously waits for the reply.
  43  */
  44 static int
  45 rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data)
  46 {
  47         u32 message = MBOX_MSG(chan, data);
  48         int ret;
  49
  50         WARN_ON(data & 0xf);
  51
  52         mutex_lock(&transaction_lock);
  53         reinit_completion(&fw->c);
  54         ret = mbox_send_message(fw->chan, &message);
  55         if (ret >= 0) {
  56                 if (wait_for_completion_timeout(&fw->c, HZ)) {
  57                         ret = 0;
  58                 } else {
  59                         ret = -ETIMEDOUT;
  60                         WARN_ONCE(1, "Firmware transaction timeout");
  61                 }
  62         } else {
  63                 dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
  64         }
  65         mutex_unlock(&transaction_lock);
  66
  67         return ret;
  68 }
  69
  70 /**
  71  * rpi_firmware_property_list - Submit firmware property list
  72  * @fw:         Pointer to firmware structure from rpi_firmware_get().
  73  * @data:       Buffer holding tags.
  74  * @tag_size:   Size of tags buffer.
  75  *
  76  * Submits a set of concatenated tags to the VPU firmware through the
  77  * mailbox property interface.
  78  *
  79  * The buffer header and the ending tag are added by this function and
  80  * don't need to be supplied, just the actual tags for your operation.
  81  * See struct rpi_firmware_property_tag_header for the per-tag
  82  * structure.
  83  */
  84 int rpi_firmware_property_list(struct rpi_firmware *fw,
  85                                void *data, size_t tag_size)
  86 {
  87         size_t size = tag_size + 12;
  88         u32 *buf;
  89         dma_addr_t bus_addr;
  90         int ret;
  91
  92         /* Packets are processed a dword at a time. */
  93         if (size & 3)
  94                 return -EINVAL;
  95
  96         buf = dma_alloc_coherent(fw->cl.dev, PAGE_ALIGN(size), &bus_addr,
  97                                  GFP_ATOMIC);
  98         if (!buf)
  99                 return -ENOMEM;
 100
 101         /* The firmware will error out without parsing in this case. */
 102         WARN_ON(size >= 1024 * 1024);
 103
 104         buf[0] = size;
 105         buf[1] = RPI_FIRMWARE_STATUS_REQUEST;
 106         memcpy(&buf[2], data, tag_size);
 107         buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END;
 108         wmb();
 109
 110         ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr);
 111
 112         rmb();
 113         memcpy(data, &buf[2], tag_size);
 114         if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) {
 115                 /*
 116                  * The tag name here might not be the one causing the
 117                  * error, if there were multiple tags in the request.
 118                  * But single-tag is the most common, so go with it.
 119                  */
 120                 dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",
 121                         buf[2], buf[1]);
 122                 ret = -EINVAL;
 123         }
 124
 125         dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr);
 126
 127         return ret;
 128 }
 129 EXPORT_SYMBOL_GPL(rpi_firmware_property_list);
 130
 131 /**
 132  * rpi_firmware_property - Submit single firmware property
 133  * @fw:         Pointer to firmware structure from rpi_firmware_get().
 134  * @tag:        One of enum_mbox_property_tag.
 135  * @tag_data:   Tag data buffer.
 136  * @buf_size:   Buffer size.
 137  *
 138  * Submits a single tag to the VPU firmware through the mailbox
 139  * property interface.
 140  *
 141  * This is a convenience wrapper around
 142  * rpi_firmware_property_list() to avoid some of the
 143  * boilerplate in property calls.
 144  */
 145 int rpi_firmware_property(struct rpi_firmware *fw,
 146                           u32 tag, void *tag_data, size_t buf_size)
 147 {
 148         struct rpi_firmware_property_tag_header *header;
 149         int ret;
 150
 151         /* Some mailboxes can use over 1k bytes. Rather than checking
 152          * size and using stack or kmalloc depending on requirements,
 153          * just use kmalloc. Mailboxes don't get called enough to worry
 154          * too much about the time taken in the allocation.
 155          */
 156         void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL);
 157
 158         if (!data)
 159                 return -ENOMEM;
 160
 161         header = data;
 162         header->tag = tag;
 163         header->buf_size = buf_size;
 164         header->req_resp_size = 0;
 165         memcpy(data + sizeof(*header), tag_data, buf_size);
 166
 167         ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header));
 168
 169         memcpy(tag_data, data + sizeof(*header), buf_size);
 170
 171         kfree(data);
 172
 173         return ret;
 174 }
 175 EXPORT_SYMBOL_GPL(rpi_firmware_property);
 176
 177 static void
 178 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
 179 {
 180         time64_t date_and_time;
 181         u32 packet;
 182         int ret = rpi_firmware_property(fw,
 183                                         RPI_FIRMWARE_GET_FIRMWARE_REVISION,
 184                                         &packet, sizeof(packet));
 185
 186         if (ret)
 187                 return;
 188
 189         /* This is not compatible with y2038 */
 190         date_and_time = packet;
 191         dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &date_and_time);
 192 }
 193
 194 static void
 195 rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw)
 196 {
 197         u32 packet;
 198         int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED,
 199                                         &packet, sizeof(packet));
 200
 201         if (ret)
 202                 return;
 203
 204         rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon",
 205                                                   -1, NULL, 0);
 206 }
 207
 208 static void rpi_register_clk_driver(struct device *dev)
 209 {
 210         struct device_node *firmware;
 211
 212         /*
 213          * Earlier DTs don't have a node for the firmware clocks but
 214          * rely on us creating a platform device by hand. If we do
 215          * have a node for the firmware clocks, just bail out here.
 216          */
 217         firmware = of_get_compatible_child(dev->of_node,
 218                                            "raspberrypi,firmware-clocks");
 219         if (firmware) {
 220                 of_node_put(firmware);
 221                 return;
 222         }
 223
 224         rpi_clk = platform_device_register_data(dev, "raspberrypi-clk",
 225                                                 -1, NULL, 0);
 226 }
 227
 228 static int rpi_firmware_probe(struct platform_device *pdev)
 229 {
 230         struct device *dev = &pdev->dev;
 231         struct rpi_firmware *fw;
 232
 233         fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL);
 234         if (!fw)
 235                 return -ENOMEM;
 236
 237         fw->cl.dev = dev;
 238         fw->cl.rx_callback = response_callback;
 239         fw->cl.tx_block = true;
 240
 241         fw->chan = mbox_request_channel(&fw->cl, 0);
 242         if (IS_ERR(fw->chan)) {
 243                 int ret = PTR_ERR(fw->chan);
 244                 if (ret != -EPROBE_DEFER)
 245                         dev_err(dev, "Failed to get mbox channel: %d\n", ret);
 246                 return ret;
 247         }
 248
 249         init_completion(&fw->c);
 250
 251         platform_set_drvdata(pdev, fw);
 252
 253         rpi_firmware_print_firmware_revision(fw);
 254         rpi_register_hwmon_driver(dev, fw);
 255         rpi_register_clk_driver(dev);
 256
 257         return 0;
 258 }
 259
 260 static void rpi_firmware_shutdown(struct platform_device *pdev)
 261 {
 262         struct rpi_firmware *fw = platform_get_drvdata(pdev);
 263
 264         if (!fw)
 265                 return;
 266
 267         rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);
 268 }
 269
 270 static int rpi_firmware_remove(struct platform_device *pdev)
 271 {
 272         struct rpi_firmware *fw = platform_get_drvdata(pdev);
 273
 274         platform_device_unregister(rpi_hwmon);
 275         rpi_hwmon = NULL;
 276         platform_device_unregister(rpi_clk);
 277         rpi_clk = NULL;
 278         mbox_free_channel(fw->chan);
 279
 280         return 0;
 281 }
 282
 283 /**
 284  * rpi_firmware_get - Get pointer to rpi_firmware structure.
 285  * @firmware_node:    Pointer to the firmware Device Tree node.
 286  *
 287  * Returns NULL is the firmware device is not ready.
 288  */
 289 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
 290 {
 291         struct platform_device *pdev = of_find_device_by_node(firmware_node);
 292
 293         if (!pdev)
 294                 return NULL;
 295
 296         return platform_get_drvdata(pdev);
 297 }
 298 EXPORT_SYMBOL_GPL(rpi_firmware_get);
 299
 300 static const struct of_device_id rpi_firmware_of_match[] = {
 301         { .compatible = "raspberrypi,bcm2835-firmware", },
 302         {},
 303 };
 304 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
 305
 306 static struct platform_driver rpi_firmware_driver = {
 307         .driver = {
 308                 .name = "raspberrypi-firmware",
 309                 .of_match_table = rpi_firmware_of_match,
 310         },
 311         .probe          = rpi_firmware_probe,
 312         .shutdown       = rpi_firmware_shutdown,
 313         .remove         = rpi_firmware_remove,
 314 };
 315 module_platform_driver(rpi_firmware_driver);
 316
 317 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
 318 MODULE_DESCRIPTION("Raspberry Pi firmware driver");
 319 MODULE_LICENSE("GPL v2");