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/module.h>
13 #include <linux/of.h>
14 #include <linux/of_platform.h>
15 #include <linux/platform_device.h>
16 #include <linux/slab.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 static struct platform_device *rpi_hwmon;
25 static struct platform_device *rpi_clk;
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 	struct kref consumers;
34 };
35 
36 static DEFINE_MUTEX(transaction_lock);
37 
38 static void response_callback(struct mbox_client *cl, void *msg)
39 {
40 	struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl);
41 	complete(&fw->c);
42 }
43 
44 /*
45  * Sends a request to the firmware through the BCM2835 mailbox driver,
46  * and synchronously waits for the reply.
47  */
48 static int
49 rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data)
50 {
51 	u32 message = MBOX_MSG(chan, data);
52 	int ret;
53 
54 	WARN_ON(data & 0xf);
55 
56 	mutex_lock(&transaction_lock);
57 	reinit_completion(&fw->c);
58 	ret = mbox_send_message(fw->chan, &message);
59 	if (ret >= 0) {
60 		if (wait_for_completion_timeout(&fw->c, HZ)) {
61 			ret = 0;
62 		} else {
63 			ret = -ETIMEDOUT;
64 			WARN_ONCE(1, "Firmware transaction timeout");
65 		}
66 	} else {
67 		dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
68 	}
69 	mutex_unlock(&transaction_lock);
70 
71 	return ret;
72 }
73 
74 /**
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.
79  *
80  * Submits a set of concatenated tags to the VPU firmware through the
81  * mailbox property interface.
82  *
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
86  * structure.
87  */
88 int rpi_firmware_property_list(struct rpi_firmware *fw,
89 			       void *data, size_t tag_size)
90 {
91 	size_t size = tag_size + 12;
92 	u32 *buf;
93 	dma_addr_t bus_addr;
94 	int ret;
95 
96 	/* Packets are processed a dword at a time. */
97 	if (size & 3)
98 		return -EINVAL;
99 
100 	buf = dma_alloc_coherent(fw->cl.dev, PAGE_ALIGN(size), &bus_addr,
101 				 GFP_ATOMIC);
102 	if (!buf)
103 		return -ENOMEM;
104 
105 	/* The firmware will error out without parsing in this case. */
106 	WARN_ON(size >= 1024 * 1024);
107 
108 	buf[0] = size;
109 	buf[1] = RPI_FIRMWARE_STATUS_REQUEST;
110 	memcpy(&buf[2], data, tag_size);
111 	buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END;
112 	wmb();
113 
114 	ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr);
115 
116 	rmb();
117 	memcpy(data, &buf[2], tag_size);
118 	if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) {
119 		/*
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.
123 		 */
124 		dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",
125 			buf[2], buf[1]);
126 		ret = -EINVAL;
127 	}
128 
129 	dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr);
130 
131 	return ret;
132 }
133 EXPORT_SYMBOL_GPL(rpi_firmware_property_list);
134 
135 /**
136  * rpi_firmware_property - Submit single firmware property
137  * @fw:		Pointer to firmware structure from rpi_firmware_get().
138  * @tag:	One of enum_mbox_property_tag.
139  * @tag_data:	Tag data buffer.
140  * @buf_size:	Buffer size.
141  *
142  * Submits a single tag to the VPU firmware through the mailbox
143  * property interface.
144  *
145  * This is a convenience wrapper around
146  * rpi_firmware_property_list() to avoid some of the
147  * boilerplate in property calls.
148  */
149 int rpi_firmware_property(struct rpi_firmware *fw,
150 			  u32 tag, void *tag_data, size_t buf_size)
151 {
152 	struct rpi_firmware_property_tag_header *header;
153 	int ret;
154 
155 	/* Some mailboxes can use over 1k bytes. Rather than checking
156 	 * size and using stack or kmalloc depending on requirements,
157 	 * just use kmalloc. Mailboxes don't get called enough to worry
158 	 * too much about the time taken in the allocation.
159 	 */
160 	void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL);
161 
162 	if (!data)
163 		return -ENOMEM;
164 
165 	header = data;
166 	header->tag = tag;
167 	header->buf_size = buf_size;
168 	header->req_resp_size = 0;
169 	memcpy(data + sizeof(*header), tag_data, buf_size);
170 
171 	ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header));
172 
173 	memcpy(tag_data, data + sizeof(*header), buf_size);
174 
175 	kfree(data);
176 
177 	return ret;
178 }
179 EXPORT_SYMBOL_GPL(rpi_firmware_property);
180 
181 static void
182 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
183 {
184 	time64_t date_and_time;
185 	u32 packet;
186 	int ret = rpi_firmware_property(fw,
187 					RPI_FIRMWARE_GET_FIRMWARE_REVISION,
188 					&packet, sizeof(packet));
189 
190 	if (ret)
191 		return;
192 
193 	/* This is not compatible with y2038 */
194 	date_and_time = packet;
195 	dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &date_and_time);
196 }
197 
198 static void
199 rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw)
200 {
201 	u32 packet;
202 	int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED,
203 					&packet, sizeof(packet));
204 
205 	if (ret)
206 		return;
207 
208 	rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon",
209 						  -1, NULL, 0);
210 }
211 
212 static void rpi_register_clk_driver(struct device *dev)
213 {
214 	struct device_node *firmware;
215 
216 	/*
217 	 * Earlier DTs don't have a node for the firmware clocks but
218 	 * rely on us creating a platform device by hand. If we do
219 	 * have a node for the firmware clocks, just bail out here.
220 	 */
221 	firmware = of_get_compatible_child(dev->of_node,
222 					   "raspberrypi,firmware-clocks");
223 	if (firmware) {
224 		of_node_put(firmware);
225 		return;
226 	}
227 
228 	rpi_clk = platform_device_register_data(dev, "raspberrypi-clk",
229 						-1, NULL, 0);
230 }
231 
232 unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw, unsigned int id)
233 {
234 	struct rpi_firmware_clk_rate_request msg =
235 		RPI_FIRMWARE_CLK_RATE_REQUEST(id);
236 	int ret;
237 
238 	ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_MAX_CLOCK_RATE,
239 				    &msg, sizeof(msg));
240 	if (ret)
241 		/*
242 		 * If our firmware doesn't support that operation, or fails, we
243 		 * assume the maximum clock rate is absolute maximum we can
244 		 * store over our type.
245 		 */
246 		 return UINT_MAX;
247 
248 	return le32_to_cpu(msg.rate);
249 }
250 EXPORT_SYMBOL_GPL(rpi_firmware_clk_get_max_rate);
251 
252 static void rpi_firmware_delete(struct kref *kref)
253 {
254 	struct rpi_firmware *fw = container_of(kref, struct rpi_firmware,
255 					       consumers);
256 
257 	mbox_free_channel(fw->chan);
258 	kfree(fw);
259 }
260 
261 void rpi_firmware_put(struct rpi_firmware *fw)
262 {
263 	kref_put(&fw->consumers, rpi_firmware_delete);
264 }
265 EXPORT_SYMBOL_GPL(rpi_firmware_put);
266 
267 static void devm_rpi_firmware_put(void *data)
268 {
269 	struct rpi_firmware *fw = data;
270 
271 	rpi_firmware_put(fw);
272 }
273 
274 static int rpi_firmware_probe(struct platform_device *pdev)
275 {
276 	struct device *dev = &pdev->dev;
277 	struct rpi_firmware *fw;
278 
279 	/*
280 	 * Memory will be freed by rpi_firmware_delete() once all users have
281 	 * released their firmware handles. Don't use devm_kzalloc() here.
282 	 */
283 	fw = kzalloc(sizeof(*fw), GFP_KERNEL);
284 	if (!fw)
285 		return -ENOMEM;
286 
287 	fw->cl.dev = dev;
288 	fw->cl.rx_callback = response_callback;
289 	fw->cl.tx_block = true;
290 
291 	fw->chan = mbox_request_channel(&fw->cl, 0);
292 	if (IS_ERR(fw->chan)) {
293 		int ret = PTR_ERR(fw->chan);
294 		kfree(fw);
295 		return dev_err_probe(dev, ret, "Failed to get mbox channel\n");
296 	}
297 
298 	init_completion(&fw->c);
299 	kref_init(&fw->consumers);
300 
301 	platform_set_drvdata(pdev, fw);
302 
303 	rpi_firmware_print_firmware_revision(fw);
304 	rpi_register_hwmon_driver(dev, fw);
305 	rpi_register_clk_driver(dev);
306 
307 	return 0;
308 }
309 
310 static void rpi_firmware_shutdown(struct platform_device *pdev)
311 {
312 	struct rpi_firmware *fw = platform_get_drvdata(pdev);
313 
314 	if (!fw)
315 		return;
316 
317 	rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);
318 }
319 
320 static int rpi_firmware_remove(struct platform_device *pdev)
321 {
322 	struct rpi_firmware *fw = platform_get_drvdata(pdev);
323 
324 	platform_device_unregister(rpi_hwmon);
325 	rpi_hwmon = NULL;
326 	platform_device_unregister(rpi_clk);
327 	rpi_clk = NULL;
328 
329 	rpi_firmware_put(fw);
330 
331 	return 0;
332 }
333 
334 static const struct of_device_id rpi_firmware_of_match[] = {
335 	{ .compatible = "raspberrypi,bcm2835-firmware", },
336 	{},
337 };
338 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
339 
340 struct device_node *rpi_firmware_find_node(void)
341 {
342 	return of_find_matching_node(NULL, rpi_firmware_of_match);
343 }
344 EXPORT_SYMBOL_GPL(rpi_firmware_find_node);
345 
346 /**
347  * rpi_firmware_get - Get pointer to rpi_firmware structure.
348  * @firmware_node:    Pointer to the firmware Device Tree node.
349  *
350  * The reference to rpi_firmware has to be released with rpi_firmware_put().
351  *
352  * Returns NULL is the firmware device is not ready.
353  */
354 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
355 {
356 	struct platform_device *pdev = of_find_device_by_node(firmware_node);
357 	struct rpi_firmware *fw;
358 
359 	if (!pdev)
360 		return NULL;
361 
362 	fw = platform_get_drvdata(pdev);
363 	if (!fw)
364 		goto err_put_device;
365 
366 	if (!kref_get_unless_zero(&fw->consumers))
367 		goto err_put_device;
368 
369 	put_device(&pdev->dev);
370 
371 	return fw;
372 
373 err_put_device:
374 	put_device(&pdev->dev);
375 	return NULL;
376 }
377 EXPORT_SYMBOL_GPL(rpi_firmware_get);
378 
379 /**
380  * devm_rpi_firmware_get - Get pointer to rpi_firmware structure.
381  * @firmware_node:    Pointer to the firmware Device Tree node.
382  *
383  * Returns NULL is the firmware device is not ready.
384  */
385 struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
386 					   struct device_node *firmware_node)
387 {
388 	struct rpi_firmware *fw;
389 
390 	fw = rpi_firmware_get(firmware_node);
391 	if (!fw)
392 		return NULL;
393 
394 	if (devm_add_action_or_reset(dev, devm_rpi_firmware_put, fw))
395 		return NULL;
396 
397 	return fw;
398 }
399 EXPORT_SYMBOL_GPL(devm_rpi_firmware_get);
400 
401 static struct platform_driver rpi_firmware_driver = {
402 	.driver = {
403 		.name = "raspberrypi-firmware",
404 		.of_match_table = rpi_firmware_of_match,
405 	},
406 	.probe		= rpi_firmware_probe,
407 	.shutdown	= rpi_firmware_shutdown,
408 	.remove		= rpi_firmware_remove,
409 };
410 module_platform_driver(rpi_firmware_driver);
411 
412 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
413 MODULE_DESCRIPTION("Raspberry Pi firmware driver");
414 MODULE_LICENSE("GPL v2");
415