drivers/firmware/raspberrypi.c

   1 /*
   2  * Defines interfaces for interacting wtih the Raspberry Pi firmware's
   3  * property channel.
   4  *
   5  * Copyright © 2015 Broadcom
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/dma-mapping.h>
  13 #include <linux/mailbox_client.h>
  14 #include <linux/module.h>
  15 #include <linux/of_platform.h>
  16 #include <linux/platform_device.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 MAX_RPI_FW_PROP_BUF_SIZE        32
  25
  26 static struct platform_device *rpi_hwmon;
  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
  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                 wait_for_completion(&fw->c);
  60                 ret = 0;
  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         /* Single tags are very small (generally 8 bytes), so the
 148          * stack should be safe.
 149          */
 150         u8 data[sizeof(struct rpi_firmware_property_tag_header) +
 151                 MAX_RPI_FW_PROP_BUF_SIZE];
 152         struct rpi_firmware_property_tag_header *header =
 153                 (struct rpi_firmware_property_tag_header *)data;
 154         int ret;
 155
 156         if (WARN_ON(buf_size > sizeof(data) - sizeof(*header)))
 157                 return -EINVAL;
 158
 159         header->tag = tag;
 160         header->buf_size = buf_size;
 161         header->req_resp_size = 0;
 162         memcpy(data + sizeof(struct rpi_firmware_property_tag_header),
 163                tag_data, buf_size);
 164
 165         ret = rpi_firmware_property_list(fw, &data, buf_size + sizeof(*header));
 166         memcpy(tag_data,
 167                data + sizeof(struct rpi_firmware_property_tag_header),
 168                buf_size);
 169
 170         return ret;
 171 }
 172 EXPORT_SYMBOL_GPL(rpi_firmware_property);
 173
 174 static void
 175 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
 176 {
 177         u32 packet;
 178         int ret = rpi_firmware_property(fw,
 179                                         RPI_FIRMWARE_GET_FIRMWARE_REVISION,
 180                                         &packet, sizeof(packet));
 181
 182         if (ret == 0) {
 183                 struct tm tm;
 184
 185                 time64_to_tm(packet, 0, &tm);
 186
 187                 dev_info(fw->cl.dev,
 188                          "Attached to firmware from %04ld-%02d-%02d %02d:%02d\n",
 189                          tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 190                          tm.tm_hour, tm.tm_min);
 191         }
 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 int rpi_firmware_probe(struct platform_device *pdev)
 209 {
 210         struct device *dev = &pdev->dev;
 211         struct rpi_firmware *fw;
 212
 213         fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL);
 214         if (!fw)
 215                 return -ENOMEM;
 216
 217         fw->cl.dev = dev;
 218         fw->cl.rx_callback = response_callback;
 219         fw->cl.tx_block = true;
 220
 221         fw->chan = mbox_request_channel(&fw->cl, 0);
 222         if (IS_ERR(fw->chan)) {
 223                 int ret = PTR_ERR(fw->chan);
 224                 if (ret != -EPROBE_DEFER)
 225                         dev_err(dev, "Failed to get mbox channel: %d\n", ret);
 226                 return ret;
 227         }
 228
 229         init_completion(&fw->c);
 230
 231         platform_set_drvdata(pdev, fw);
 232
 233         rpi_firmware_print_firmware_revision(fw);
 234         rpi_register_hwmon_driver(dev, fw);
 235
 236         return 0;
 237 }
 238
 239 static int rpi_firmware_remove(struct platform_device *pdev)
 240 {
 241         struct rpi_firmware *fw = platform_get_drvdata(pdev);
 242
 243         platform_device_unregister(rpi_hwmon);
 244         rpi_hwmon = NULL;
 245         mbox_free_channel(fw->chan);
 246
 247         return 0;
 248 }
 249
 250 /**
 251  * rpi_firmware_get - Get pointer to rpi_firmware structure.
 252  * @firmware_node:    Pointer to the firmware Device Tree node.
 253  *
 254  * Returns NULL is the firmware device is not ready.
 255  */
 256 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
 257 {
 258         struct platform_device *pdev = of_find_device_by_node(firmware_node);
 259
 260         if (!pdev)
 261                 return NULL;
 262
 263         return platform_get_drvdata(pdev);
 264 }
 265 EXPORT_SYMBOL_GPL(rpi_firmware_get);
 266
 267 static const struct of_device_id rpi_firmware_of_match[] = {
 268         { .compatible = "raspberrypi,bcm2835-firmware", },
 269         {},
 270 };
 271 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
 272
 273 static struct platform_driver rpi_firmware_driver = {
 274         .driver = {
 275                 .name = "raspberrypi-firmware",
 276                 .of_match_table = rpi_firmware_of_match,
 277         },
 278         .probe          = rpi_firmware_probe,
 279         .remove         = rpi_firmware_remove,
 280 };
 281 module_platform_driver(rpi_firmware_driver);
 282
 283 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
 284 MODULE_DESCRIPTION("Raspberry Pi firmware driver");
 285 MODULE_LICENSE("GPL v2");