root/drivers/firmware/raspberrypi.c

DEFINITIONS

1. response_callback
2. rpi_firmware_transaction
3. rpi_firmware_property_list
4. rpi_firmware_property
5. rpi_firmware_print_firmware_revision
6. rpi_register_hwmon_driver
7. rpi_register_clk_driver
8. rpi_firmware_probe
9. rpi_firmware_shutdown
10. rpi_firmware_remove
11. rpi_firmware_get

   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 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         u32 packet;
 181         int ret = rpi_firmware_property(fw,
 182                                         RPI_FIRMWARE_GET_FIRMWARE_REVISION,
 183                                         &packet, sizeof(packet));
 184 
 185         if (ret == 0) {
 186                 struct tm tm;
 187 
 188                 time64_to_tm(packet, 0, &tm);
 189 
 190                 dev_info(fw->cl.dev,
 191                          "Attached to firmware from %04ld-%02d-%02d %02d:%02d\n",
 192                          tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 193                          tm.tm_hour, tm.tm_min);
 194         }
 195 }
 196 
 197 static void
 198 rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw)
 199 {
 200         u32 packet;
 201         int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED,
 202                                         &packet, sizeof(packet));
 203 
 204         if (ret)
 205                 return;
 206 
 207         rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon",
 208                                                   -1, NULL, 0);
 209 }
 210 
 211 static void rpi_register_clk_driver(struct device *dev)
 212 {
 213         rpi_clk = platform_device_register_data(dev, "raspberrypi-clk",
 214                                                 -1, NULL, 0);
 215 }
 216 
 217 static int rpi_firmware_probe(struct platform_device *pdev)
 218 {
 219         struct device *dev = &pdev->dev;
 220         struct rpi_firmware *fw;
 221 
 222         fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL);
 223         if (!fw)
 224                 return -ENOMEM;
 225 
 226         fw->cl.dev = dev;
 227         fw->cl.rx_callback = response_callback;
 228         fw->cl.tx_block = true;
 229 
 230         fw->chan = mbox_request_channel(&fw->cl, 0);
 231         if (IS_ERR(fw->chan)) {
 232                 int ret = PTR_ERR(fw->chan);
 233                 if (ret != -EPROBE_DEFER)
 234                         dev_err(dev, "Failed to get mbox channel: %d\n", ret);
 235                 return ret;
 236         }
 237 
 238         init_completion(&fw->c);
 239 
 240         platform_set_drvdata(pdev, fw);
 241 
 242         rpi_firmware_print_firmware_revision(fw);
 243         rpi_register_hwmon_driver(dev, fw);
 244         rpi_register_clk_driver(dev);
 245 
 246         return 0;
 247 }
 248 
 249 static void rpi_firmware_shutdown(struct platform_device *pdev)
 250 {
 251         struct rpi_firmware *fw = platform_get_drvdata(pdev);
 252 
 253         if (!fw)
 254                 return;
 255 
 256         rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);
 257 }
 258 
 259 static int rpi_firmware_remove(struct platform_device *pdev)
 260 {
 261         struct rpi_firmware *fw = platform_get_drvdata(pdev);
 262 
 263         platform_device_unregister(rpi_hwmon);
 264         rpi_hwmon = NULL;
 265         platform_device_unregister(rpi_clk);
 266         rpi_clk = NULL;
 267         mbox_free_channel(fw->chan);
 268 
 269         return 0;
 270 }
 271 
 272 /**
 273  * rpi_firmware_get - Get pointer to rpi_firmware structure.
 274  * @firmware_node:    Pointer to the firmware Device Tree node.
 275  *
 276  * Returns NULL is the firmware device is not ready.
 277  */
 278 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
 279 {
 280         struct platform_device *pdev = of_find_device_by_node(firmware_node);
 281 
 282         if (!pdev)
 283                 return NULL;
 284 
 285         return platform_get_drvdata(pdev);
 286 }
 287 EXPORT_SYMBOL_GPL(rpi_firmware_get);
 288 
 289 static const struct of_device_id rpi_firmware_of_match[] = {
 290         { .compatible = "raspberrypi,bcm2835-firmware", },
 291         {},
 292 };
 293 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
 294 
 295 static struct platform_driver rpi_firmware_driver = {
 296         .driver = {
 297                 .name = "raspberrypi-firmware",
 298                 .of_match_table = rpi_firmware_of_match,
 299         },
 300         .probe          = rpi_firmware_probe,
 301         .shutdown       = rpi_firmware_shutdown,
 302         .remove         = rpi_firmware_remove,
 303 };
 304 module_platform_driver(rpi_firmware_driver);
 305 
 306 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
 307 MODULE_DESCRIPTION("Raspberry Pi firmware driver");
 308 MODULE_LICENSE("GPL v2");