1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Defines interfaces for interacting with the Raspberry Pi firmware's
4  * property channel.
5  *
6  * Copyright © 2015 Broadcom
7  */
8 
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>
14 #include <linux/of.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 static struct platform_device *rpi_clk;
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 	struct kref consumers;
35 };
36 
37 static DEFINE_MUTEX(transaction_lock);
38 
39 static void response_callback(struct mbox_client *cl, void *msg)
40 {
41 	struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl);
42 	complete(&fw->c);
43 }
44 
45 /*
46  * Sends a request to the firmware through the BCM2835 mailbox driver,
47  * and synchronously waits for the reply.
48  */
49 static int
50 rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data)
51 {
52 	u32 message = MBOX_MSG(chan, data);
53 	int ret;
54 
55 	WARN_ON(data & 0xf);
56 
57 	mutex_lock(&transaction_lock);
58 	reinit_completion(&fw->c);
59 	ret = mbox_send_message(fw->chan, &message);
60 	if (ret >= 0) {
61 		if (wait_for_completion_timeout(&fw->c, HZ)) {
62 			ret = 0;
63 		} else {
64 			ret = -ETIMEDOUT;
65 			WARN_ONCE(1, "Firmware transaction timeout");
66 		}
67 	} else {
68 		dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
69 	}
70 	mutex_unlock(&transaction_lock);
71 
72 	return ret;
73 }
74 
75 /**
76  * rpi_firmware_property_list - Submit firmware property list
77  * @fw:		Pointer to firmware structure from rpi_firmware_get().
78  * @data:	Buffer holding tags.
79  * @tag_size:	Size of tags buffer.
80  *
81  * Submits a set of concatenated tags to the VPU firmware through the
82  * mailbox property interface.
83  *
84  * The buffer header and the ending tag are added by this function and
85  * don't need to be supplied, just the actual tags for your operation.
86  * See struct rpi_firmware_property_tag_header for the per-tag
87  * structure.
88  */
89 int rpi_firmware_property_list(struct rpi_firmware *fw,
90 			       void *data, size_t tag_size)
91 {
92 	size_t size = tag_size + 12;
93 	u32 *buf;
94 	dma_addr_t bus_addr;
95 	int ret;
96 
97 	/* Packets are processed a dword at a time. */
98 	if (size & 3)
99 		return -EINVAL;
100 
101 	buf = dma_alloc_coherent(fw->chan->mbox->dev, PAGE_ALIGN(size),
102 				 &bus_addr, GFP_ATOMIC);
103 	if (!buf)
104 		return -ENOMEM;
105 
106 	/* The firmware will error out without parsing in this case. */
107 	WARN_ON(size >= 1024 * 1024);
108 
109 	buf[0] = size;
110 	buf[1] = RPI_FIRMWARE_STATUS_REQUEST;
111 	memcpy(&buf[2], data, tag_size);
112 	buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END;
113 	wmb();
114 
115 	ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr);
116 
117 	rmb();
118 	memcpy(data, &buf[2], tag_size);
119 	if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) {
120 		/*
121 		 * The tag name here might not be the one causing the
122 		 * error, if there were multiple tags in the request.
123 		 * But single-tag is the most common, so go with it.
124 		 */
125 		dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",
126 			buf[2], buf[1]);
127 		ret = -EINVAL;
128 	}
129 
130 	dma_free_coherent(fw->chan->mbox->dev, PAGE_ALIGN(size), buf, bus_addr);
131 
132 	return ret;
133 }
134 EXPORT_SYMBOL_GPL(rpi_firmware_property_list);
135 
136 /**
137  * rpi_firmware_property - Submit single firmware property
138  * @fw:		Pointer to firmware structure from rpi_firmware_get().
139  * @tag:	One of enum_mbox_property_tag.
140  * @tag_data:	Tag data buffer.
141  * @buf_size:	Buffer size.
142  *
143  * Submits a single tag to the VPU firmware through the mailbox
144  * property interface.
145  *
146  * This is a convenience wrapper around
147  * rpi_firmware_property_list() to avoid some of the
148  * boilerplate in property calls.
149  */
150 int rpi_firmware_property(struct rpi_firmware *fw,
151 			  u32 tag, void *tag_data, size_t buf_size)
152 {
153 	struct rpi_firmware_property_tag_header *header;
154 	int ret;
155 
156 	/* Some mailboxes can use over 1k bytes. Rather than checking
157 	 * size and using stack or kmalloc depending on requirements,
158 	 * just use kmalloc. Mailboxes don't get called enough to worry
159 	 * too much about the time taken in the allocation.
160 	 */
161 	void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL);
162 
163 	if (!data)
164 		return -ENOMEM;
165 
166 	header = data;
167 	header->tag = tag;
168 	header->buf_size = buf_size;
169 	header->req_resp_size = 0;
170 	memcpy(data + sizeof(*header), tag_data, buf_size);
171 
172 	ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header));
173 
174 	memcpy(tag_data, data + sizeof(*header), buf_size);
175 
176 	kfree(data);
177 
178 	return ret;
179 }
180 EXPORT_SYMBOL_GPL(rpi_firmware_property);
181 
182 static void
183 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
184 {
185 	time64_t date_and_time;
186 	u32 packet;
187 	int ret = rpi_firmware_property(fw,
188 					RPI_FIRMWARE_GET_FIRMWARE_REVISION,
189 					&packet, sizeof(packet));
190 
191 	if (ret)
192 		return;
193 
194 	/* This is not compatible with y2038 */
195 	date_and_time = packet;
196 	dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &date_and_time);
197 }
198 
199 static void
200 rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw)
201 {
202 	u32 packet;
203 	int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED,
204 					&packet, sizeof(packet));
205 
206 	if (ret)
207 		return;
208 
209 	rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon",
210 						  -1, NULL, 0);
211 }
212 
213 static void rpi_register_clk_driver(struct device *dev)
214 {
215 	struct device_node *firmware;
216 
217 	/*
218 	 * Earlier DTs don't have a node for the firmware clocks but
219 	 * rely on us creating a platform device by hand. If we do
220 	 * have a node for the firmware clocks, just bail out here.
221 	 */
222 	firmware = of_get_compatible_child(dev->of_node,
223 					   "raspberrypi,firmware-clocks");
224 	if (firmware) {
225 		of_node_put(firmware);
226 		return;
227 	}
228 
229 	rpi_clk = platform_device_register_data(dev, "raspberrypi-clk",
230 						-1, NULL, 0);
231 }
232 
233 unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw, unsigned int id)
234 {
235 	struct rpi_firmware_clk_rate_request msg =
236 		RPI_FIRMWARE_CLK_RATE_REQUEST(id);
237 	int ret;
238 
239 	ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_MAX_CLOCK_RATE,
240 				    &msg, sizeof(msg));
241 	if (ret)
242 		/*
243 		 * If our firmware doesn't support that operation, or fails, we
244 		 * assume the maximum clock rate is absolute maximum we can
245 		 * store over our type.
246 		 */
247 		 return UINT_MAX;
248 
249 	return le32_to_cpu(msg.rate);
250 }
251 EXPORT_SYMBOL_GPL(rpi_firmware_clk_get_max_rate);
252 
253 static void rpi_firmware_delete(struct kref *kref)
254 {
255 	struct rpi_firmware *fw = container_of(kref, struct rpi_firmware,
256 					       consumers);
257 
258 	mbox_free_channel(fw->chan);
259 	kfree(fw);
260 }
261 
262 void rpi_firmware_put(struct rpi_firmware *fw)
263 {
264 	kref_put(&fw->consumers, rpi_firmware_delete);
265 }
266 EXPORT_SYMBOL_GPL(rpi_firmware_put);
267 
268 static void devm_rpi_firmware_put(void *data)
269 {
270 	struct rpi_firmware *fw = data;
271 
272 	rpi_firmware_put(fw);
273 }
274 
275 static int rpi_firmware_probe(struct platform_device *pdev)
276 {
277 	struct device *dev = &pdev->dev;
278 	struct rpi_firmware *fw;
279 
280 	/*
281 	 * Memory will be freed by rpi_firmware_delete() once all users have
282 	 * released their firmware handles. Don't use devm_kzalloc() here.
283 	 */
284 	fw = kzalloc(sizeof(*fw), GFP_KERNEL);
285 	if (!fw)
286 		return -ENOMEM;
287 
288 	fw->cl.dev = dev;
289 	fw->cl.rx_callback = response_callback;
290 	fw->cl.tx_block = true;
291 
292 	fw->chan = mbox_request_channel(&fw->cl, 0);
293 	if (IS_ERR(fw->chan)) {
294 		int ret = PTR_ERR(fw->chan);
295 		kfree(fw);
296 		return dev_err_probe(dev, ret, "Failed to get mbox channel\n");
297 	}
298 
299 	init_completion(&fw->c);
300 	kref_init(&fw->consumers);
301 
302 	platform_set_drvdata(pdev, fw);
303 
304 	rpi_firmware_print_firmware_revision(fw);
305 	rpi_register_hwmon_driver(dev, fw);
306 	rpi_register_clk_driver(dev);
307 
308 	return 0;
309 }
310 
311 static void rpi_firmware_shutdown(struct platform_device *pdev)
312 {
313 	struct rpi_firmware *fw = platform_get_drvdata(pdev);
314 
315 	if (!fw)
316 		return;
317 
318 	rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);
319 }
320 
321 static int rpi_firmware_remove(struct platform_device *pdev)
322 {
323 	struct rpi_firmware *fw = platform_get_drvdata(pdev);
324 
325 	platform_device_unregister(rpi_hwmon);
326 	rpi_hwmon = NULL;
327 	platform_device_unregister(rpi_clk);
328 	rpi_clk = NULL;
329 
330 	rpi_firmware_put(fw);
331 
332 	return 0;
333 }
334 
335 static const struct of_device_id rpi_firmware_of_match[] = {
336 	{ .compatible = "raspberrypi,bcm2835-firmware", },
337 	{},
338 };
339 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
340 
341 struct device_node *rpi_firmware_find_node(void)
342 {
343 	return of_find_matching_node(NULL, rpi_firmware_of_match);
344 }
345 EXPORT_SYMBOL_GPL(rpi_firmware_find_node);
346 
347 /**
348  * rpi_firmware_get - Get pointer to rpi_firmware structure.
349  * @firmware_node:    Pointer to the firmware Device Tree node.
350  *
351  * The reference to rpi_firmware has to be released with rpi_firmware_put().
352  *
353  * Returns NULL is the firmware device is not ready.
354  */
355 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
356 {
357 	struct platform_device *pdev = of_find_device_by_node(firmware_node);
358 	struct rpi_firmware *fw;
359 
360 	if (!pdev)
361 		return NULL;
362 
363 	fw = platform_get_drvdata(pdev);
364 	if (!fw)
365 		goto err_put_device;
366 
367 	if (!kref_get_unless_zero(&fw->consumers))
368 		goto err_put_device;
369 
370 	put_device(&pdev->dev);
371 
372 	return fw;
373 
374 err_put_device:
375 	put_device(&pdev->dev);
376 	return NULL;
377 }
378 EXPORT_SYMBOL_GPL(rpi_firmware_get);
379 
380 /**
381  * devm_rpi_firmware_get - Get pointer to rpi_firmware structure.
382  * @firmware_node:    Pointer to the firmware Device Tree node.
383  *
384  * Returns NULL is the firmware device is not ready.
385  */
386 struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
387 					   struct device_node *firmware_node)
388 {
389 	struct rpi_firmware *fw;
390 
391 	fw = rpi_firmware_get(firmware_node);
392 	if (!fw)
393 		return NULL;
394 
395 	if (devm_add_action_or_reset(dev, devm_rpi_firmware_put, fw))
396 		return NULL;
397 
398 	return fw;
399 }
400 EXPORT_SYMBOL_GPL(devm_rpi_firmware_get);
401 
402 static struct platform_driver rpi_firmware_driver = {
403 	.driver = {
404 		.name = "raspberrypi-firmware",
405 		.of_match_table = rpi_firmware_of_match,
406 	},
407 	.probe		= rpi_firmware_probe,
408 	.shutdown	= rpi_firmware_shutdown,
409 	.remove		= rpi_firmware_remove,
410 };
411 module_platform_driver(rpi_firmware_driver);
412 
413 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
414 MODULE_DESCRIPTION("Raspberry Pi firmware driver");
415 MODULE_LICENSE("GPL v2");
416