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
231static void rpi_firmware_delete(struct kref *kref)
232{
233	struct rpi_firmware *fw = container_of(kref, struct rpi_firmware,
234					       consumers);
235
236	mbox_free_channel(fw->chan);
237	kfree(fw);
238}
239
240void rpi_firmware_put(struct rpi_firmware *fw)
241{
242	kref_put(&fw->consumers, rpi_firmware_delete);
243}
244EXPORT_SYMBOL_GPL(rpi_firmware_put);
245
246static void devm_rpi_firmware_put(void *data)
247{
248	struct rpi_firmware *fw = data;
249
250	rpi_firmware_put(fw);
251}
252
253static int rpi_firmware_probe(struct platform_device *pdev)
254{
255	struct device *dev = &pdev->dev;
256	struct rpi_firmware *fw;
257
258	/*
259	 * Memory will be freed by rpi_firmware_delete() once all users have
260	 * released their firmware handles. Don't use devm_kzalloc() here.
261	 */
262	fw = kzalloc(sizeof(*fw), GFP_KERNEL);
263	if (!fw)
264		return -ENOMEM;
265
266	fw->cl.dev = dev;
267	fw->cl.rx_callback = response_callback;
268	fw->cl.tx_block = true;
269
270	fw->chan = mbox_request_channel(&fw->cl, 0);
271	if (IS_ERR(fw->chan)) {
272		int ret = PTR_ERR(fw->chan);
273		if (ret != -EPROBE_DEFER)
274			dev_err(dev, "Failed to get mbox channel: %d\n", ret);
275		return ret;
276	}
277
278	init_completion(&fw->c);
279	kref_init(&fw->consumers);
280
281	platform_set_drvdata(pdev, fw);
282
283	rpi_firmware_print_firmware_revision(fw);
284	rpi_register_hwmon_driver(dev, fw);
285	rpi_register_clk_driver(dev);
286
287	return 0;
288}
289
290static void rpi_firmware_shutdown(struct platform_device *pdev)
291{
292	struct rpi_firmware *fw = platform_get_drvdata(pdev);
293
294	if (!fw)
295		return;
296
297	rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);
298}
299
300static int rpi_firmware_remove(struct platform_device *pdev)
301{
302	struct rpi_firmware *fw = platform_get_drvdata(pdev);
303
304	platform_device_unregister(rpi_hwmon);
305	rpi_hwmon = NULL;
306	platform_device_unregister(rpi_clk);
307	rpi_clk = NULL;
308
309	rpi_firmware_put(fw);
310
311	return 0;
312}
313
314/**
315 * rpi_firmware_get - Get pointer to rpi_firmware structure.
316 * @firmware_node:    Pointer to the firmware Device Tree node.
317 *
318 * The reference to rpi_firmware has to be released with rpi_firmware_put().
319 *
320 * Returns NULL is the firmware device is not ready.
321 */
322struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
323{
324	struct platform_device *pdev = of_find_device_by_node(firmware_node);
325	struct rpi_firmware *fw;
326
327	if (!pdev)
328		return NULL;
329
330	fw = platform_get_drvdata(pdev);
331	if (!fw)
332		goto err_put_device;
333
334	if (!kref_get_unless_zero(&fw->consumers))
335		goto err_put_device;
336
337	put_device(&pdev->dev);
338
339	return fw;
340
341err_put_device:
342	put_device(&pdev->dev);
343	return NULL;
344}
345EXPORT_SYMBOL_GPL(rpi_firmware_get);
346
347/**
348 * devm_rpi_firmware_get - Get pointer to rpi_firmware structure.
349 * @firmware_node:    Pointer to the firmware Device Tree node.
350 *
351 * Returns NULL is the firmware device is not ready.
352 */
353struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
354					   struct device_node *firmware_node)
355{
356	struct rpi_firmware *fw;
357
358	fw = rpi_firmware_get(firmware_node);
359	if (!fw)
360		return NULL;
361
362	if (devm_add_action_or_reset(dev, devm_rpi_firmware_put, fw))
363		return NULL;
364
365	return fw;
366}
367EXPORT_SYMBOL_GPL(devm_rpi_firmware_get);
368
369static const struct of_device_id rpi_firmware_of_match[] = {
370	{ .compatible = "raspberrypi,bcm2835-firmware", },
371	{},
372};
373MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
374
375static struct platform_driver rpi_firmware_driver = {
376	.driver = {
377		.name = "raspberrypi-firmware",
378		.of_match_table = rpi_firmware_of_match,
379	},
380	.probe		= rpi_firmware_probe,
381	.shutdown	= rpi_firmware_shutdown,
382	.remove		= rpi_firmware_remove,
383};
384module_platform_driver(rpi_firmware_driver);
385
386MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
387MODULE_DESCRIPTION("Raspberry Pi firmware driver");
388MODULE_LICENSE("GPL v2");