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_platform.h>
 14#include <linux/platform_device.h>
 15#include <linux/slab.h>
 16#include <soc/bcm2835/raspberrypi-firmware.h>
 17
 18#define MBOX_MSG(chan, data28)		(((data28) & ~0xf) | ((chan) & 0xf))
 19#define MBOX_CHAN(msg)			((msg) & 0xf)
 20#define MBOX_DATA28(msg)		((msg) & ~0xf)
 21#define MBOX_CHAN_PROPERTY		8
 22
 23static struct platform_device *rpi_hwmon;
 24static struct platform_device *rpi_clk;
 25
 26struct rpi_firmware {
 27	struct mbox_client cl;
 28	struct mbox_chan *chan; /* The property channel. */
 29	struct completion c;
 30	u32 enabled;
 31
 32	struct kref consumers;
 33};
 34
 35static DEFINE_MUTEX(transaction_lock);
 36
 37static void response_callback(struct mbox_client *cl, void *msg)
 38{
 39	struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl);
 40	complete(&fw->c);
 41}
 42
 43/*
 44 * Sends a request to the firmware through the BCM2835 mailbox driver,
 45 * and synchronously waits for the reply.
 46 */
 47static int
 48rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data)
 49{
 50	u32 message = MBOX_MSG(chan, data);
 51	int ret;
 52
 53	WARN_ON(data & 0xf);
 54
 55	mutex_lock(&transaction_lock);
 56	reinit_completion(&fw->c);
 57	ret = mbox_send_message(fw->chan, &message);
 58	if (ret >= 0) {
 59		if (wait_for_completion_timeout(&fw->c, HZ)) {
 60			ret = 0;
 61		} else {
 62			ret = -ETIMEDOUT;
 63			WARN_ONCE(1, "Firmware transaction timeout");
 64		}
 65	} else {
 66		dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
 67	}
 68	mutex_unlock(&transaction_lock);
 69
 70	return ret;
 71}
 72
 73/**
 74 * rpi_firmware_property_list - Submit firmware property list
 75 * @fw:		Pointer to firmware structure from rpi_firmware_get().
 76 * @data:	Buffer holding tags.
 77 * @tag_size:	Size of tags buffer.
 78 *
 79 * Submits a set of concatenated tags to the VPU firmware through the
 80 * mailbox property interface.
 81 *
 82 * The buffer header and the ending tag are added by this function and
 83 * don't need to be supplied, just the actual tags for your operation.
 84 * See struct rpi_firmware_property_tag_header for the per-tag
 85 * structure.
 86 */
 87int rpi_firmware_property_list(struct rpi_firmware *fw,
 88			       void *data, size_t tag_size)
 89{
 90	size_t size = tag_size + 12;
 91	u32 *buf;
 92	dma_addr_t bus_addr;
 93	int ret;
 94
 95	/* Packets are processed a dword at a time. */
 96	if (size & 3)
 97		return -EINVAL;
 98
 99	buf = dma_alloc_coherent(fw->cl.dev, PAGE_ALIGN(size), &bus_addr,
100				 GFP_ATOMIC);
101	if (!buf)
102		return -ENOMEM;
103
104	/* The firmware will error out without parsing in this case. */
105	WARN_ON(size >= 1024 * 1024);
106
107	buf[0] = size;
108	buf[1] = RPI_FIRMWARE_STATUS_REQUEST;
109	memcpy(&buf[2], data, tag_size);
110	buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END;
111	wmb();
112
113	ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr);
114
115	rmb();
116	memcpy(data, &buf[2], tag_size);
117	if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) {
118		/*
119		 * The tag name here might not be the one causing the
120		 * error, if there were multiple tags in the request.
121		 * But single-tag is the most common, so go with it.
122		 */
123		dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",
124			buf[2], buf[1]);
125		ret = -EINVAL;
126	}
127
128	dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr);
129
130	return ret;
131}
132EXPORT_SYMBOL_GPL(rpi_firmware_property_list);
133
134/**
135 * rpi_firmware_property - Submit single firmware property
136 * @fw:		Pointer to firmware structure from rpi_firmware_get().
137 * @tag:	One of enum_mbox_property_tag.
138 * @tag_data:	Tag data buffer.
139 * @buf_size:	Buffer size.
140 *
141 * Submits a single tag to the VPU firmware through the mailbox
142 * property interface.
143 *
144 * This is a convenience wrapper around
145 * rpi_firmware_property_list() to avoid some of the
146 * boilerplate in property calls.
147 */
148int rpi_firmware_property(struct rpi_firmware *fw,
149			  u32 tag, void *tag_data, size_t buf_size)
150{
151	struct rpi_firmware_property_tag_header *header;
152	int ret;
153
154	/* Some mailboxes can use over 1k bytes. Rather than checking
155	 * size and using stack or kmalloc depending on requirements,
156	 * just use kmalloc. Mailboxes don't get called enough to worry
157	 * too much about the time taken in the allocation.
158	 */
159	void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL);
160
161	if (!data)
162		return -ENOMEM;
163
164	header = data;
165	header->tag = tag;
166	header->buf_size = buf_size;
167	header->req_resp_size = 0;
168	memcpy(data + sizeof(*header), tag_data, buf_size);
169
170	ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header));
171
172	memcpy(tag_data, data + sizeof(*header), buf_size);
173
174	kfree(data);
175
176	return ret;
177}
178EXPORT_SYMBOL_GPL(rpi_firmware_property);
179
180static void
181rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
182{
183	time64_t date_and_time;
184	u32 packet;
185	int ret = rpi_firmware_property(fw,
186					RPI_FIRMWARE_GET_FIRMWARE_REVISION,
187					&packet, sizeof(packet));
188
189	if (ret)
190		return;
191
192	/* This is not compatible with y2038 */
193	date_and_time = packet;
194	dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &date_and_time);
195}
196
197static void
198rpi_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
211static void rpi_register_clk_driver(struct device *dev)
212{
213	struct device_node *firmware;
214
215	/*
216	 * Earlier DTs don't have a node for the firmware clocks but
217	 * rely on us creating a platform device by hand. If we do
218	 * have a node for the firmware clocks, just bail out here.
219	 */
220	firmware = of_get_compatible_child(dev->of_node,
221					   "raspberrypi,firmware-clocks");
222	if (firmware) {
223		of_node_put(firmware);
224		return;
225	}
226
227	rpi_clk = platform_device_register_data(dev, "raspberrypi-clk",
228						-1, NULL, 0);
229}
230
231unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw, unsigned int id)
232{
233	struct rpi_firmware_clk_rate_request msg =
234		RPI_FIRMWARE_CLK_RATE_REQUEST(id);
235	int ret;
236
237	ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_MAX_CLOCK_RATE,
238				    &msg, sizeof(msg));
239	if (ret)
240		/*
241		 * If our firmware doesn't support that operation, or fails, we
242		 * assume the maximum clock rate is absolute maximum we can
243		 * store over our type.
244		 */
245		 return UINT_MAX;
246
247	return le32_to_cpu(msg.rate);
248}
249EXPORT_SYMBOL_GPL(rpi_firmware_clk_get_max_rate);
250
251static void rpi_firmware_delete(struct kref *kref)
252{
253	struct rpi_firmware *fw = container_of(kref, struct rpi_firmware,
254					       consumers);
255
256	mbox_free_channel(fw->chan);
257	kfree(fw);
258}
259
260void rpi_firmware_put(struct rpi_firmware *fw)
261{
262	kref_put(&fw->consumers, rpi_firmware_delete);
263}
264EXPORT_SYMBOL_GPL(rpi_firmware_put);
265
266static void devm_rpi_firmware_put(void *data)
267{
268	struct rpi_firmware *fw = data;
269
270	rpi_firmware_put(fw);
271}
272
273static int rpi_firmware_probe(struct platform_device *pdev)
274{
275	struct device *dev = &pdev->dev;
276	struct rpi_firmware *fw;
277
278	/*
279	 * Memory will be freed by rpi_firmware_delete() once all users have
280	 * released their firmware handles. Don't use devm_kzalloc() here.
281	 */
282	fw = kzalloc(sizeof(*fw), GFP_KERNEL);
283	if (!fw)
284		return -ENOMEM;
285
286	fw->cl.dev = dev;
287	fw->cl.rx_callback = response_callback;
288	fw->cl.tx_block = true;
289
290	fw->chan = mbox_request_channel(&fw->cl, 0);
291	if (IS_ERR(fw->chan)) {
292		int ret = PTR_ERR(fw->chan);
293		kfree(fw);
294		return dev_err_probe(dev, ret, "Failed to get mbox channel\n");
295	}
296
297	init_completion(&fw->c);
298	kref_init(&fw->consumers);
299
300	platform_set_drvdata(pdev, fw);
301
302	rpi_firmware_print_firmware_revision(fw);
303	rpi_register_hwmon_driver(dev, fw);
304	rpi_register_clk_driver(dev);
305
306	return 0;
307}
308
309static void rpi_firmware_shutdown(struct platform_device *pdev)
310{
311	struct rpi_firmware *fw = platform_get_drvdata(pdev);
312
313	if (!fw)
314		return;
315
316	rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);
317}
318
319static int rpi_firmware_remove(struct platform_device *pdev)
320{
321	struct rpi_firmware *fw = platform_get_drvdata(pdev);
322
323	platform_device_unregister(rpi_hwmon);
324	rpi_hwmon = NULL;
325	platform_device_unregister(rpi_clk);
326	rpi_clk = NULL;
327
328	rpi_firmware_put(fw);
329
330	return 0;
331}
332
333static const struct of_device_id rpi_firmware_of_match[] = {
334	{ .compatible = "raspberrypi,bcm2835-firmware", },
335	{},
336};
337MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
338
339struct device_node *rpi_firmware_find_node(void)
340{
341	return of_find_matching_node(NULL, rpi_firmware_of_match);
342}
343EXPORT_SYMBOL_GPL(rpi_firmware_find_node);
344
345/**
346 * rpi_firmware_get - Get pointer to rpi_firmware structure.
347 * @firmware_node:    Pointer to the firmware Device Tree node.
348 *
349 * The reference to rpi_firmware has to be released with rpi_firmware_put().
350 *
351 * Returns NULL is the firmware device is not ready.
352 */
353struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
354{
355	struct platform_device *pdev = of_find_device_by_node(firmware_node);
356	struct rpi_firmware *fw;
357
358	if (!pdev)
359		return NULL;
360
361	fw = platform_get_drvdata(pdev);
362	if (!fw)
363		goto err_put_device;
364
365	if (!kref_get_unless_zero(&fw->consumers))
366		goto err_put_device;
367
368	put_device(&pdev->dev);
369
370	return fw;
371
372err_put_device:
373	put_device(&pdev->dev);
374	return NULL;
375}
376EXPORT_SYMBOL_GPL(rpi_firmware_get);
377
378/**
379 * devm_rpi_firmware_get - Get pointer to rpi_firmware structure.
380 * @firmware_node:    Pointer to the firmware Device Tree node.
381 *
382 * Returns NULL is the firmware device is not ready.
383 */
384struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
385					   struct device_node *firmware_node)
386{
387	struct rpi_firmware *fw;
388
389	fw = rpi_firmware_get(firmware_node);
390	if (!fw)
391		return NULL;
392
393	if (devm_add_action_or_reset(dev, devm_rpi_firmware_put, fw))
394		return NULL;
395
396	return fw;
397}
398EXPORT_SYMBOL_GPL(devm_rpi_firmware_get);
399
400static struct platform_driver rpi_firmware_driver = {
401	.driver = {
402		.name = "raspberrypi-firmware",
403		.of_match_table = rpi_firmware_of_match,
404	},
405	.probe		= rpi_firmware_probe,
406	.shutdown	= rpi_firmware_shutdown,
407	.remove		= rpi_firmware_remove,
408};
409module_platform_driver(rpi_firmware_driver);
410
411MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
412MODULE_DESCRIPTION("Raspberry Pi firmware driver");
413MODULE_LICENSE("GPL v2");