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 <linux/slab.h>
  18 #include <soc/bcm2835/raspberrypi-firmware.h>
  19
  20 #define MBOX_MSG(chan, data28)          (((data28) & ~0xf) | ((chan) & 0xf))
  21 #define MBOX_CHAN(msg)                  ((msg) & 0xf)
  22 #define MBOX_DATA28(msg)                ((msg) & ~0xf)
  23 #define MBOX_CHAN_PROPERTY              8
  24
  25 static struct platform_device *rpi_hwmon;
  26
  27 struct rpi_firmware {
  28         struct mbox_client cl;
  29         struct mbox_chan *chan; /* The property channel. */
  30         struct completion c;
  31         u32 enabled;
  32 };
  33
  34 static DEFINE_MUTEX(transaction_lock);
  35
  36 static void response_callback(struct mbox_client *cl, void *msg)
  37 {
  38         struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl);
  39         complete(&fw->c);
  40 }
  41
  42 /*
  43  * Sends a request to the firmware through the BCM2835 mailbox driver,
  44  * and synchronously waits for the reply.
  45  */
  46 static int
  47 rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data)
  48 {
  49         u32 message = MBOX_MSG(chan, data);
  50         int ret;
  51
  52         WARN_ON(data & 0xf);
  53
  54         mutex_lock(&transaction_lock);
  55         reinit_completion(&fw->c);
  56         ret = mbox_send_message(fw->chan, &message);
  57         if (ret >= 0) {
  58                 wait_for_completion(&fw->c);
  59                 ret = 0;
  60         } else {
  61                 dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
  62         }
  63         mutex_unlock(&transaction_lock);
  64
  65         return ret;
  66 }
  67
  68 /**
  69  * rpi_firmware_property_list - Submit firmware property list
  70  * @fw:         Pointer to firmware structure from rpi_firmware_get().
  71  * @data:       Buffer holding tags.
  72  * @tag_size:   Size of tags buffer.
  73  *
  74  * Submits a set of concatenated tags to the VPU firmware through the
  75  * mailbox property interface.
  76  *
  77  * The buffer header and the ending tag are added by this function and
  78  * don't need to be supplied, just the actual tags for your operation.
  79  * See struct rpi_firmware_property_tag_header for the per-tag
  80  * structure.
  81  */
  82 int rpi_firmware_property_list(struct rpi_firmware *fw,
  83                                void *data, size_t tag_size)
  84 {
  85         size_t size = tag_size + 12;
  86         u32 *buf;
  87         dma_addr_t bus_addr;
  88         int ret;
  89
  90         /* Packets are processed a dword at a time. */
  91         if (size & 3)
  92                 return -EINVAL;
  93
  94         buf = dma_alloc_coherent(fw->cl.dev, PAGE_ALIGN(size), &bus_addr,
  95                                  GFP_ATOMIC);
  96         if (!buf)
  97                 return -ENOMEM;
  98
  99         /* The firmware will error out without parsing in this case. */
 100         WARN_ON(size >= 1024 * 1024);
 101
 102         buf[0] = size;
 103         buf[1] = RPI_FIRMWARE_STATUS_REQUEST;
 104         memcpy(&buf[2], data, tag_size);
 105         buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END;
 106         wmb();
 107
 108         ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr);
 109
 110         rmb();
 111         memcpy(data, &buf[2], tag_size);
 112         if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) {
 113                 /*
 114                  * The tag name here might not be the one causing the
 115                  * error, if there were multiple tags in the request.
 116                  * But single-tag is the most common, so go with it.
 117                  */
 118                 dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",
 119                         buf[2], buf[1]);
 120                 ret = -EINVAL;
 121         }
 122
 123         dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr);
 124
 125         return ret;
 126 }
 127 EXPORT_SYMBOL_GPL(rpi_firmware_property_list);
 128
 129 /**
 130  * rpi_firmware_property - Submit single firmware property
 131  * @fw:         Pointer to firmware structure from rpi_firmware_get().
 132  * @tag:        One of enum_mbox_property_tag.
 133  * @tag_data:   Tag data buffer.
 134  * @buf_size:   Buffer size.
 135  *
 136  * Submits a single tag to the VPU firmware through the mailbox
 137  * property interface.
 138  *
 139  * This is a convenience wrapper around
 140  * rpi_firmware_property_list() to avoid some of the
 141  * boilerplate in property calls.
 142  */
 143 int rpi_firmware_property(struct rpi_firmware *fw,
 144                           u32 tag, void *tag_data, size_t buf_size)
 145 {
 146         struct rpi_firmware_property_tag_header *header;
 147         int ret;
 148
 149         /* Some mailboxes can use over 1k bytes. Rather than checking
 150          * size and using stack or kmalloc depending on requirements,
 151          * just use kmalloc. Mailboxes don't get called enough to worry
 152          * too much about the time taken in the allocation.
 153          */
 154         void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL);
 155
 156         if (!data)
 157                 return -ENOMEM;
 158
 159         header = data;
 160         header->tag = tag;
 161         header->buf_size = buf_size;
 162         header->req_resp_size = 0;
 163         memcpy(data + sizeof(*header), tag_data, buf_size);
 164
 165         ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header));
 166
 167         memcpy(tag_data, data + sizeof(*header), buf_size);
 168
 169         kfree(data);
 170
 171         return ret;
 172 }
 173 EXPORT_SYMBOL_GPL(rpi_firmware_property);
 174
 175 static void
 176 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
 177 {
 178         u32 packet;
 179         int ret = rpi_firmware_property(fw,
 180                                         RPI_FIRMWARE_GET_FIRMWARE_REVISION,
 181                                         &packet, sizeof(packet));
 182
 183         if (ret == 0) {
 184                 struct tm tm;
 185
 186                 time64_to_tm(packet, 0, &tm);
 187
 188                 dev_info(fw->cl.dev,
 189                          "Attached to firmware from %04ld-%02d-%02d %02d:%02d\n",
 190                          tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 191                          tm.tm_hour, tm.tm_min);
 192         }
 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 int rpi_firmware_probe(struct platform_device *pdev)
 210 {
 211         struct device *dev = &pdev->dev;
 212         struct rpi_firmware *fw;
 213
 214         fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL);
 215         if (!fw)
 216                 return -ENOMEM;
 217
 218         fw->cl.dev = dev;
 219         fw->cl.rx_callback = response_callback;
 220         fw->cl.tx_block = true;
 221
 222         fw->chan = mbox_request_channel(&fw->cl, 0);
 223         if (IS_ERR(fw->chan)) {
 224                 int ret = PTR_ERR(fw->chan);
 225                 if (ret != -EPROBE_DEFER)
 226                         dev_err(dev, "Failed to get mbox channel: %d\n", ret);
 227                 return ret;
 228         }
 229
 230         init_completion(&fw->c);
 231
 232         platform_set_drvdata(pdev, fw);
 233
 234         rpi_firmware_print_firmware_revision(fw);
 235         rpi_register_hwmon_driver(dev, fw);
 236
 237         return 0;
 238 }
 239
 240 static int rpi_firmware_remove(struct platform_device *pdev)
 241 {
 242         struct rpi_firmware *fw = platform_get_drvdata(pdev);
 243
 244         platform_device_unregister(rpi_hwmon);
 245         rpi_hwmon = NULL;
 246         mbox_free_channel(fw->chan);
 247
 248         return 0;
 249 }
 250
 251 /**
 252  * rpi_firmware_get - Get pointer to rpi_firmware structure.
 253  * @firmware_node:    Pointer to the firmware Device Tree node.
 254  *
 255  * Returns NULL is the firmware device is not ready.
 256  */
 257 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
 258 {
 259         struct platform_device *pdev = of_find_device_by_node(firmware_node);
 260
 261         if (!pdev)
 262                 return NULL;
 263
 264         return platform_get_drvdata(pdev);
 265 }
 266 EXPORT_SYMBOL_GPL(rpi_firmware_get);
 267
 268 static const struct of_device_id rpi_firmware_of_match[] = {
 269         { .compatible = "raspberrypi,bcm2835-firmware", },
 270         {},
 271 };
 272 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
 273
 274 static struct platform_driver rpi_firmware_driver = {
 275         .driver = {
 276                 .name = "raspberrypi-firmware",
 277                 .of_match_table = rpi_firmware_of_match,
 278         },
 279         .probe          = rpi_firmware_probe,
 280         .remove         = rpi_firmware_remove,
 281 };
 282 module_platform_driver(rpi_firmware_driver);
 283
 284 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
 285 MODULE_DESCRIPTION("Raspberry Pi firmware driver");
 286 MODULE_LICENSE("GPL v2");