1 // SPDX-License-Identifier: GPL-2.0
3 * Defines interfaces for interacting with the Raspberry Pi firmware's
6 * Copyright © 2015 Broadcom
9 #include <linux/dma-mapping.h>
10 #include <linux/kref.h>
11 #include <linux/mailbox_client.h>
12 #include <linux/mailbox_controller.h>
13 #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>
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
25 static struct platform_device *rpi_hwmon;
26 static struct platform_device *rpi_clk;
29 struct mbox_client cl;
30 struct mbox_chan *chan; /* The property channel. */
34 struct kref consumers;
37 static DEFINE_MUTEX(transaction_lock);
39 static void response_callback(struct mbox_client *cl, void *msg)
41 struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl);
46 * Sends a request to the firmware through the BCM2835 mailbox driver,
47 * and synchronously waits for the reply.
50 rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data)
52 u32 message = MBOX_MSG(chan, data);
57 mutex_lock(&transaction_lock);
58 reinit_completion(&fw->c);
59 ret = mbox_send_message(fw->chan, &message);
61 if (wait_for_completion_timeout(&fw->c, HZ)) {
67 dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
69 mutex_unlock(&transaction_lock);
75 * rpi_firmware_property_list - Submit firmware property list
76 * @fw: Pointer to firmware structure from rpi_firmware_get().
77 * @data: Buffer holding tags.
78 * @tag_size: Size of tags buffer.
80 * Submits a set of concatenated tags to the VPU firmware through the
81 * mailbox property interface.
83 * The buffer header and the ending tag are added by this function and
84 * don't need to be supplied, just the actual tags for your operation.
85 * See struct rpi_firmware_property_tag_header for the per-tag
88 int rpi_firmware_property_list(struct rpi_firmware *fw,
89 void *data, size_t tag_size)
91 size_t size = tag_size + 12;
96 /* Packets are processed a dword at a time. */
100 buf = dma_alloc_coherent(fw->chan->mbox->dev, PAGE_ALIGN(size),
101 &bus_addr, GFP_ATOMIC);
105 /* The firmware will error out without parsing in this case. */
106 WARN_ON(size >= 1024 * 1024);
109 buf[1] = RPI_FIRMWARE_STATUS_REQUEST;
110 memcpy(&buf[2], data, tag_size);
111 buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END;
114 ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr);
117 memcpy(data, &buf[2], tag_size);
118 if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) {
120 * The tag name here might not be the one causing the
121 * error, if there were multiple tags in the request.
122 * But single-tag is the most common, so go with it.
124 dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",
127 } else if (ret == -ETIMEDOUT) {
128 WARN_ONCE(1, "Firmware transaction 0x%08x timeout", buf[2]);
131 dma_free_coherent(fw->chan->mbox->dev, PAGE_ALIGN(size), buf, bus_addr);
135 EXPORT_SYMBOL_GPL(rpi_firmware_property_list);
138 * rpi_firmware_property - Submit single firmware property
139 * @fw: Pointer to firmware structure from rpi_firmware_get().
140 * @tag: One of enum_mbox_property_tag.
141 * @tag_data: Tag data buffer.
142 * @buf_size: Buffer size.
144 * Submits a single tag to the VPU firmware through the mailbox
145 * property interface.
147 * This is a convenience wrapper around
148 * rpi_firmware_property_list() to avoid some of the
149 * boilerplate in property calls.
151 int rpi_firmware_property(struct rpi_firmware *fw,
152 u32 tag, void *tag_data, size_t buf_size)
154 struct rpi_firmware_property_tag_header *header;
157 /* Some mailboxes can use over 1k bytes. Rather than checking
158 * size and using stack or kmalloc depending on requirements,
159 * just use kmalloc. Mailboxes don't get called enough to worry
160 * too much about the time taken in the allocation.
162 void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL);
169 header->buf_size = buf_size;
170 header->req_resp_size = 0;
171 memcpy(data + sizeof(*header), tag_data, buf_size);
173 ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header));
175 memcpy(tag_data, data + sizeof(*header), buf_size);
181 EXPORT_SYMBOL_GPL(rpi_firmware_property);
184 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
186 time64_t date_and_time;
188 int ret = rpi_firmware_property(fw,
189 RPI_FIRMWARE_GET_FIRMWARE_REVISION,
190 &packet, sizeof(packet));
195 /* This is not compatible with y2038 */
196 date_and_time = packet;
197 dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &date_and_time);
201 rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw)
204 int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED,
205 &packet, sizeof(packet));
210 rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon",
214 static void rpi_register_clk_driver(struct device *dev)
216 struct device_node *firmware;
219 * Earlier DTs don't have a node for the firmware clocks but
220 * rely on us creating a platform device by hand. If we do
221 * have a node for the firmware clocks, just bail out here.
223 firmware = of_get_compatible_child(dev->of_node,
224 "raspberrypi,firmware-clocks");
226 of_node_put(firmware);
230 rpi_clk = platform_device_register_data(dev, "raspberrypi-clk",
234 unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw, unsigned int id)
236 struct rpi_firmware_clk_rate_request msg =
237 RPI_FIRMWARE_CLK_RATE_REQUEST(id);
240 ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_MAX_CLOCK_RATE,
244 * If our firmware doesn't support that operation, or fails, we
245 * assume the maximum clock rate is absolute maximum we can
246 * store over our type.
250 return le32_to_cpu(msg.rate);
252 EXPORT_SYMBOL_GPL(rpi_firmware_clk_get_max_rate);
254 static void rpi_firmware_delete(struct kref *kref)
256 struct rpi_firmware *fw = container_of(kref, struct rpi_firmware,
259 mbox_free_channel(fw->chan);
263 void rpi_firmware_put(struct rpi_firmware *fw)
265 kref_put(&fw->consumers, rpi_firmware_delete);
267 EXPORT_SYMBOL_GPL(rpi_firmware_put);
269 static void devm_rpi_firmware_put(void *data)
271 struct rpi_firmware *fw = data;
273 rpi_firmware_put(fw);
276 static int rpi_firmware_probe(struct platform_device *pdev)
278 struct device *dev = &pdev->dev;
279 struct rpi_firmware *fw;
282 * Memory will be freed by rpi_firmware_delete() once all users have
283 * released their firmware handles. Don't use devm_kzalloc() here.
285 fw = kzalloc(sizeof(*fw), GFP_KERNEL);
290 fw->cl.rx_callback = response_callback;
291 fw->cl.tx_block = true;
293 fw->chan = mbox_request_channel(&fw->cl, 0);
294 if (IS_ERR(fw->chan)) {
295 int ret = PTR_ERR(fw->chan);
297 return dev_err_probe(dev, ret, "Failed to get mbox channel\n");
300 init_completion(&fw->c);
301 kref_init(&fw->consumers);
303 platform_set_drvdata(pdev, fw);
305 rpi_firmware_print_firmware_revision(fw);
306 rpi_register_hwmon_driver(dev, fw);
307 rpi_register_clk_driver(dev);
312 static void rpi_firmware_shutdown(struct platform_device *pdev)
314 struct rpi_firmware *fw = platform_get_drvdata(pdev);
319 rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);
322 static void rpi_firmware_remove(struct platform_device *pdev)
324 struct rpi_firmware *fw = platform_get_drvdata(pdev);
326 platform_device_unregister(rpi_hwmon);
328 platform_device_unregister(rpi_clk);
331 rpi_firmware_put(fw);
334 static const struct of_device_id rpi_firmware_of_match[] = {
335 { .compatible = "raspberrypi,bcm2835-firmware", },
338 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
340 struct device_node *rpi_firmware_find_node(void)
342 return of_find_matching_node(NULL, rpi_firmware_of_match);
344 EXPORT_SYMBOL_GPL(rpi_firmware_find_node);
347 * rpi_firmware_get - Get pointer to rpi_firmware structure.
348 * @firmware_node: Pointer to the firmware Device Tree node.
350 * The reference to rpi_firmware has to be released with rpi_firmware_put().
352 * Returns NULL is the firmware device is not ready.
354 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
356 struct platform_device *pdev = of_find_device_by_node(firmware_node);
357 struct rpi_firmware *fw;
362 fw = platform_get_drvdata(pdev);
366 if (!kref_get_unless_zero(&fw->consumers))
369 put_device(&pdev->dev);
374 put_device(&pdev->dev);
377 EXPORT_SYMBOL_GPL(rpi_firmware_get);
380 * devm_rpi_firmware_get - Get pointer to rpi_firmware structure.
381 * @dev: The firmware device structure
382 * @firmware_node: Pointer to the firmware Device Tree node.
384 * Returns NULL is the firmware device is not ready.
386 struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
387 struct device_node *firmware_node)
389 struct rpi_firmware *fw;
391 fw = rpi_firmware_get(firmware_node);
395 if (devm_add_action_or_reset(dev, devm_rpi_firmware_put, fw))
400 EXPORT_SYMBOL_GPL(devm_rpi_firmware_get);
402 static struct platform_driver rpi_firmware_driver = {
404 .name = "raspberrypi-firmware",
405 .of_match_table = rpi_firmware_of_match,
407 .probe = rpi_firmware_probe,
408 .shutdown = rpi_firmware_shutdown,
409 .remove_new = rpi_firmware_remove,
411 module_platform_driver(rpi_firmware_driver);
413 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
414 MODULE_DESCRIPTION("Raspberry Pi firmware driver");
415 MODULE_LICENSE("GPL v2");