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 <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
  24 struct rpi_firmware {
  25         struct mbox_client cl;
  26         struct mbox_chan *chan; /* The property channel. */
  27         struct completion c;
  28         u32 enabled;
  29 };
  30
  31 static DEFINE_MUTEX(transaction_lock);
  32
  33 static void response_callback(struct mbox_client *cl, void *msg)
  34 {
  35         struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl);
  36         complete(&fw->c);
  37 }
  38
  39 /*
  40  * Sends a request to the firmware through the BCM2835 mailbox driver,
  41  * and synchronously waits for the reply.
  42  */
  43 static int
  44 rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data)
  45 {
  46         u32 message = MBOX_MSG(chan, data);
  47         int ret;
  48
  49         WARN_ON(data & 0xf);
  50
  51         mutex_lock(&transaction_lock);
  52         reinit_completion(&fw->c);
  53         ret = mbox_send_message(fw->chan, &message);
  54         if (ret >= 0) {
  55                 if (wait_for_completion_timeout(&fw->c, HZ)) {
  56                         ret = 0;
  57                 } else {
  58                         ret = -ETIMEDOUT;
  59                         WARN_ONCE(1, "Firmware transaction timeout");
  60                 }
  61         } else {
  62                 dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
  63         }
  64         mutex_unlock(&transaction_lock);
  65
  66         return ret;
  67 }
  68
  69 /**
  70  * rpi_firmware_property_list - Submit firmware property list
  71  * @fw:         Pointer to firmware structure from rpi_firmware_get().
  72  * @data:       Buffer holding tags.
  73  * @tag_size:   Size of tags buffer.
  74  *
  75  * Submits a set of concatenated tags to the VPU firmware through the
  76  * mailbox property interface.
  77  *
  78  * The buffer header and the ending tag are added by this function and
  79  * don't need to be supplied, just the actual tags for your operation.
  80  * See struct rpi_firmware_property_tag_header for the per-tag
  81  * structure.
  82  */
  83 int rpi_firmware_property_list(struct rpi_firmware *fw,
  84                                void *data, size_t tag_size)
  85 {
  86         size_t size = tag_size + 12;
  87         u32 *buf;
  88         dma_addr_t bus_addr;
  89         int ret;
  90
  91         /* Packets are processed a dword at a time. */
  92         if (size & 3)
  93                 return -EINVAL;
  94
  95         buf = dma_alloc_coherent(fw->cl.dev, PAGE_ALIGN(size), &bus_addr,
  96                                  GFP_ATOMIC);
  97         if (!buf)
  98                 return -ENOMEM;
  99
 100         /* The firmware will error out without parsing in this case. */
 101         WARN_ON(size >= 1024 * 1024);
 102
 103         buf[0] = size;
 104         buf[1] = RPI_FIRMWARE_STATUS_REQUEST;
 105         memcpy(&buf[2], data, tag_size);
 106         buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END;
 107         wmb();
 108
 109         ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr);
 110
 111         rmb();
 112         memcpy(data, &buf[2], tag_size);
 113         if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) {
 114                 /*
 115                  * The tag name here might not be the one causing the
 116                  * error, if there were multiple tags in the request.
 117                  * But single-tag is the most common, so go with it.
 118                  */
 119                 dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",
 120                         buf[2], buf[1]);
 121                 ret = -EINVAL;
 122         }
 123
 124         dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr);
 125
 126         return ret;
 127 }
 128 EXPORT_SYMBOL_GPL(rpi_firmware_property_list);
 129
 130 /**
 131  * rpi_firmware_property - Submit single firmware property
 132  * @fw:         Pointer to firmware structure from rpi_firmware_get().
 133  * @tag:        One of enum_mbox_property_tag.
 134  * @tag_data:   Tag data buffer.
 135  * @buf_size:   Buffer size.
 136  *
 137  * Submits a single tag to the VPU firmware through the mailbox
 138  * property interface.
 139  *
 140  * This is a convenience wrapper around
 141  * rpi_firmware_property_list() to avoid some of the
 142  * boilerplate in property calls.
 143  */
 144 int rpi_firmware_property(struct rpi_firmware *fw,
 145                           u32 tag, void *tag_data, size_t buf_size)
 146 {
 147         struct rpi_firmware_property_tag_header *header;
 148         int ret;
 149
 150         /* Some mailboxes can use over 1k bytes. Rather than checking
 151          * size and using stack or kmalloc depending on requirements,
 152          * just use kmalloc. Mailboxes don't get called enough to worry
 153          * too much about the time taken in the allocation.
 154          */
 155         void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL);
 156
 157         if (!data)
 158                 return -ENOMEM;
 159
 160         header = data;
 161         header->tag = tag;
 162         header->buf_size = buf_size;
 163         header->req_resp_size = 0;
 164         memcpy(data + sizeof(*header), tag_data, buf_size);
 165
 166         ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header));
 167
 168         memcpy(tag_data, data + sizeof(*header), buf_size);
 169
 170         kfree(data);
 171
 172         return ret;
 173 }
 174 EXPORT_SYMBOL_GPL(rpi_firmware_property);
 175
 176 static void
 177 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
 178 {
 179         u32 packet;
 180         int ret = rpi_firmware_property(fw,
 181                                         RPI_FIRMWARE_GET_FIRMWARE_REVISION,
 182                                         &packet, sizeof(packet));
 183
 184         if (ret == 0) {
 185                 struct tm tm;
 186
 187                 time64_to_tm(packet, 0, &tm);
 188
 189                 dev_info(fw->cl.dev,
 190                          "Attached to firmware from %04ld-%02d-%02d %02d:%02d\n",
 191                          tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 192                          tm.tm_hour, tm.tm_min);
 193         }
 194 }
 195
 196 static void
 197 rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw)
 198 {
 199         u32 packet;
 200         int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED,
 201                                         &packet, sizeof(packet));
 202
 203         if (ret)
 204                 return;
 205
 206         rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon",
 207                                                   -1, NULL, 0);
 208 }
 209
 210 static int rpi_firmware_probe(struct platform_device *pdev)
 211 {
 212         struct device *dev = &pdev->dev;
 213         struct rpi_firmware *fw;
 214
 215         fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL);
 216         if (!fw)
 217                 return -ENOMEM;
 218
 219         fw->cl.dev = dev;
 220         fw->cl.rx_callback = response_callback;
 221         fw->cl.tx_block = true;
 222
 223         fw->chan = mbox_request_channel(&fw->cl, 0);
 224         if (IS_ERR(fw->chan)) {
 225                 int ret = PTR_ERR(fw->chan);
 226                 if (ret != -EPROBE_DEFER)
 227                         dev_err(dev, "Failed to get mbox channel: %d\n", ret);
 228                 return ret;
 229         }
 230
 231         init_completion(&fw->c);
 232
 233         platform_set_drvdata(pdev, fw);
 234
 235         rpi_firmware_print_firmware_revision(fw);
 236         rpi_register_hwmon_driver(dev, fw);
 237
 238         return 0;
 239 }
 240
 241 static int rpi_firmware_remove(struct platform_device *pdev)
 242 {
 243         struct rpi_firmware *fw = platform_get_drvdata(pdev);
 244
 245         platform_device_unregister(rpi_hwmon);
 246         rpi_hwmon = NULL;
 247         mbox_free_channel(fw->chan);
 248
 249         return 0;
 250 }
 251
 252 /**
 253  * rpi_firmware_get - Get pointer to rpi_firmware structure.
 254  * @firmware_node:    Pointer to the firmware Device Tree node.
 255  *
 256  * Returns NULL is the firmware device is not ready.
 257  */
 258 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
 259 {
 260         struct platform_device *pdev = of_find_device_by_node(firmware_node);
 261
 262         if (!pdev)
 263                 return NULL;
 264
 265         return platform_get_drvdata(pdev);
 266 }
 267 EXPORT_SYMBOL_GPL(rpi_firmware_get);
 268
 269 static const struct of_device_id rpi_firmware_of_match[] = {
 270         { .compatible = "raspberrypi,bcm2835-firmware", },
 271         {},
 272 };
 273 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
 274
 275 static struct platform_driver rpi_firmware_driver = {
 276         .driver = {
 277                 .name = "raspberrypi-firmware",
 278                 .of_match_table = rpi_firmware_of_match,
 279         },
 280         .probe          = rpi_firmware_probe,
 281         .remove         = rpi_firmware_remove,
 282 };
 283 module_platform_driver(rpi_firmware_driver);
 284
 285 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
 286 MODULE_DESCRIPTION("Raspberry Pi firmware driver");
 287 MODULE_LICENSE("GPL v2");