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 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                 wait_for_completion(&fw->c);
  56                 ret = 0;
  57         } else {
  58                 dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
  59         }
  60         mutex_unlock(&transaction_lock);
  61
  62         return ret;
  63 }
  64
  65 /**
  66  * rpi_firmware_property_list - Submit firmware property list
  67  * @fw:         Pointer to firmware structure from rpi_firmware_get().
  68  * @data:       Buffer holding tags.
  69  * @tag_size:   Size of tags buffer.
  70  *
  71  * Submits a set of concatenated tags to the VPU firmware through the
  72  * mailbox property interface.
  73  *
  74  * The buffer header and the ending tag are added by this function and
  75  * don't need to be supplied, just the actual tags for your operation.
  76  * See struct rpi_firmware_property_tag_header for the per-tag
  77  * structure.
  78  */
  79 int rpi_firmware_property_list(struct rpi_firmware *fw,
  80                                void *data, size_t tag_size)
  81 {
  82         size_t size = tag_size + 12;
  83         u32 *buf;
  84         dma_addr_t bus_addr;
  85         int ret;
  86
  87         /* Packets are processed a dword at a time. */
  88         if (size & 3)
  89                 return -EINVAL;
  90
  91         buf = dma_alloc_coherent(fw->cl.dev, PAGE_ALIGN(size), &bus_addr,
  92                                  GFP_ATOMIC);
  93         if (!buf)
  94                 return -ENOMEM;
  95
  96         /* The firmware will error out without parsing in this case. */
  97         WARN_ON(size >= 1024 * 1024);
  98
  99         buf[0] = size;
 100         buf[1] = RPI_FIRMWARE_STATUS_REQUEST;
 101         memcpy(&buf[2], data, tag_size);
 102         buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END;
 103         wmb();
 104
 105         ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr);
 106
 107         rmb();
 108         memcpy(data, &buf[2], tag_size);
 109         if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) {
 110                 /*
 111                  * The tag name here might not be the one causing the
 112                  * error, if there were multiple tags in the request.
 113                  * But single-tag is the most common, so go with it.
 114                  */
 115                 dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",
 116                         buf[2], buf[1]);
 117                 ret = -EINVAL;
 118         }
 119
 120         dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr);
 121
 122         return ret;
 123 }
 124 EXPORT_SYMBOL_GPL(rpi_firmware_property_list);
 125
 126 /**
 127  * rpi_firmware_property - Submit single firmware property
 128  * @fw:         Pointer to firmware structure from rpi_firmware_get().
 129  * @tag:        One of enum_mbox_property_tag.
 130  * @tag_data:   Tag data buffer.
 131  * @buf_size:   Buffer size.
 132  *
 133  * Submits a single tag to the VPU firmware through the mailbox
 134  * property interface.
 135  *
 136  * This is a convenience wrapper around
 137  * rpi_firmware_property_list() to avoid some of the
 138  * boilerplate in property calls.
 139  */
 140 int rpi_firmware_property(struct rpi_firmware *fw,
 141                           u32 tag, void *tag_data, size_t buf_size)
 142 {
 143         /* Single tags are very small (generally 8 bytes), so the
 144          * stack should be safe.
 145          */
 146         u8 data[buf_size + sizeof(struct rpi_firmware_property_tag_header)];
 147         struct rpi_firmware_property_tag_header *header =
 148                 (struct rpi_firmware_property_tag_header *)data;
 149         int ret;
 150
 151         header->tag = tag;
 152         header->buf_size = buf_size;
 153         header->req_resp_size = 0;
 154         memcpy(data + sizeof(struct rpi_firmware_property_tag_header),
 155                tag_data, buf_size);
 156
 157         ret = rpi_firmware_property_list(fw, &data, sizeof(data));
 158         memcpy(tag_data,
 159                data + sizeof(struct rpi_firmware_property_tag_header),
 160                buf_size);
 161
 162         return ret;
 163 }
 164 EXPORT_SYMBOL_GPL(rpi_firmware_property);
 165
 166 static void
 167 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
 168 {
 169         u32 packet;
 170         int ret = rpi_firmware_property(fw,
 171                                         RPI_FIRMWARE_GET_FIRMWARE_REVISION,
 172                                         &packet, sizeof(packet));
 173
 174         if (ret == 0) {
 175                 struct tm tm;
 176
 177                 time64_to_tm(packet, 0, &tm);
 178
 179                 dev_info(fw->cl.dev,
 180                          "Attached to firmware from %04ld-%02d-%02d %02d:%02d\n",
 181                          tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 182                          tm.tm_hour, tm.tm_min);
 183         }
 184 }
 185
 186 static int rpi_firmware_probe(struct platform_device *pdev)
 187 {
 188         struct device *dev = &pdev->dev;
 189         struct rpi_firmware *fw;
 190
 191         fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL);
 192         if (!fw)
 193                 return -ENOMEM;
 194
 195         fw->cl.dev = dev;
 196         fw->cl.rx_callback = response_callback;
 197         fw->cl.tx_block = true;
 198
 199         fw->chan = mbox_request_channel(&fw->cl, 0);
 200         if (IS_ERR(fw->chan)) {
 201                 int ret = PTR_ERR(fw->chan);
 202                 if (ret != -EPROBE_DEFER)
 203                         dev_err(dev, "Failed to get mbox channel: %d\n", ret);
 204                 return ret;
 205         }
 206
 207         init_completion(&fw->c);
 208
 209         platform_set_drvdata(pdev, fw);
 210
 211         rpi_firmware_print_firmware_revision(fw);
 212
 213         return 0;
 214 }
 215
 216 static int rpi_firmware_remove(struct platform_device *pdev)
 217 {
 218         struct rpi_firmware *fw = platform_get_drvdata(pdev);
 219
 220         mbox_free_channel(fw->chan);
 221
 222         return 0;
 223 }
 224
 225 /**
 226  * rpi_firmware_get - Get pointer to rpi_firmware structure.
 227  * @firmware_node:    Pointer to the firmware Device Tree node.
 228  *
 229  * Returns NULL is the firmware device is not ready.
 230  */
 231 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
 232 {
 233         struct platform_device *pdev = of_find_device_by_node(firmware_node);
 234
 235         if (!pdev)
 236                 return NULL;
 237
 238         return platform_get_drvdata(pdev);
 239 }
 240 EXPORT_SYMBOL_GPL(rpi_firmware_get);
 241
 242 static const struct of_device_id rpi_firmware_of_match[] = {
 243         { .compatible = "raspberrypi,bcm2835-firmware", },
 244         {},
 245 };
 246 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
 247
 248 static struct platform_driver rpi_firmware_driver = {
 249         .driver = {
 250                 .name = "raspberrypi-firmware",
 251                 .of_match_table = rpi_firmware_of_match,
 252         },
 253         .probe          = rpi_firmware_probe,
 254         .remove         = rpi_firmware_remove,
 255 };
 256 module_platform_driver(rpi_firmware_driver);
 257
 258 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
 259 MODULE_DESCRIPTION("Raspberry Pi firmware driver");
 260 MODULE_LICENSE("GPL v2");