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
 24static struct platform_device *rpi_hwmon;
 25static struct platform_device *rpi_clk;
 26
 27struct 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
 36static DEFINE_MUTEX(transaction_lock);
 37
 38static 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 */
 48static int
 49rpi_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 */
 88int 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}
133EXPORT_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 */
149int 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}
179EXPORT_SYMBOL_GPL(rpi_firmware_property);
180
181static void
182rpi_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
198static void
199rpi_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
212static 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
232unsigned 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}
250EXPORT_SYMBOL_GPL(rpi_firmware_clk_get_max_rate);
251
252static 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
261void rpi_firmware_put(struct rpi_firmware *fw)
262{
263	kref_put(&fw->consumers, rpi_firmware_delete);
264}
265EXPORT_SYMBOL_GPL(rpi_firmware_put);
266
267static void devm_rpi_firmware_put(void *data)
268{
269	struct rpi_firmware *fw = data;
270
271	rpi_firmware_put(fw);
272}
273
274static 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
310static 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
320static void 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
332static const struct of_device_id rpi_firmware_of_match[] = {
333	{ .compatible = "raspberrypi,bcm2835-firmware", },
334	{},
335};
336MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
337
338struct device_node *rpi_firmware_find_node(void)
339{
340	return of_find_matching_node(NULL, rpi_firmware_of_match);
341}
342EXPORT_SYMBOL_GPL(rpi_firmware_find_node);
343
344/**
345 * rpi_firmware_get - Get pointer to rpi_firmware structure.
346 * @firmware_node:    Pointer to the firmware Device Tree node.
347 *
348 * The reference to rpi_firmware has to be released with rpi_firmware_put().
349 *
350 * Returns NULL is the firmware device is not ready.
351 */
352struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
353{
354	struct platform_device *pdev = of_find_device_by_node(firmware_node);
355	struct rpi_firmware *fw;
356
357	if (!pdev)
358		return NULL;
359
360	fw = platform_get_drvdata(pdev);
361	if (!fw)
362		goto err_put_device;
363
364	if (!kref_get_unless_zero(&fw->consumers))
365		goto err_put_device;
366
367	put_device(&pdev->dev);
368
369	return fw;
370
371err_put_device:
372	put_device(&pdev->dev);
373	return NULL;
374}
375EXPORT_SYMBOL_GPL(rpi_firmware_get);
376
377/**
378 * devm_rpi_firmware_get - Get pointer to rpi_firmware structure.
379 * @dev:              The firmware device 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_new	= 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");