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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
25static struct platform_device *rpi_hwmon;
26static struct platform_device *rpi_clk;
27
28struct 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
37static DEFINE_MUTEX(transaction_lock);
38
39static 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 */
49static int
50rpi_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 }
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->chan->mbox->dev, PAGE_ALIGN(size),
101 &bus_addr, 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 } else if (ret == -ETIMEDOUT) {
128 WARN_ONCE(1, "Firmware transaction 0x%08x timeout", buf[2]);
129 }
130
131 dma_free_coherent(fw->chan->mbox->dev, PAGE_ALIGN(size), buf, bus_addr);
132
133 return ret;
134}
135EXPORT_SYMBOL_GPL(rpi_firmware_property_list);
136
137/**
138 * rpi_firmware_property - Submit single firmware property
139 * @fw: Pointer to firmware structure from rpi_firmware_get().
140 * @tag: One of enum_mbox_property_tag.
141 * @tag_data: Tag data buffer.
142 * @buf_size: Buffer size.
143 *
144 * Submits a single tag to the VPU firmware through the mailbox
145 * property interface.
146 *
147 * This is a convenience wrapper around
148 * rpi_firmware_property_list() to avoid some of the
149 * boilerplate in property calls.
150 */
151int rpi_firmware_property(struct rpi_firmware *fw,
152 u32 tag, void *tag_data, size_t buf_size)
153{
154 struct rpi_firmware_property_tag_header *header;
155 int ret;
156
157 /* Some mailboxes can use over 1k bytes. Rather than checking
158 * size and using stack or kmalloc depending on requirements,
159 * just use kmalloc. Mailboxes don't get called enough to worry
160 * too much about the time taken in the allocation.
161 */
162 void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL);
163
164 if (!data)
165 return -ENOMEM;
166
167 header = data;
168 header->tag = tag;
169 header->buf_size = buf_size;
170 header->req_resp_size = 0;
171 memcpy(data + sizeof(*header), tag_data, buf_size);
172
173 ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header));
174
175 memcpy(tag_data, data + sizeof(*header), buf_size);
176
177 kfree(data);
178
179 return ret;
180}
181EXPORT_SYMBOL_GPL(rpi_firmware_property);
182
183static void
184rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
185{
186 time64_t date_and_time;
187 u32 packet;
188 int ret = rpi_firmware_property(fw,
189 RPI_FIRMWARE_GET_FIRMWARE_REVISION,
190 &packet, sizeof(packet));
191
192 if (ret)
193 return;
194
195 /* This is not compatible with y2038 */
196 date_and_time = packet;
197 dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &date_and_time);
198}
199
200static void
201rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw)
202{
203 u32 packet;
204 int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED,
205 &packet, sizeof(packet));
206
207 if (ret)
208 return;
209
210 rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon",
211 -1, NULL, 0);
212}
213
214static void rpi_register_clk_driver(struct device *dev)
215{
216 struct device_node *firmware;
217
218 /*
219 * Earlier DTs don't have a node for the firmware clocks but
220 * rely on us creating a platform device by hand. If we do
221 * have a node for the firmware clocks, just bail out here.
222 */
223 firmware = of_get_compatible_child(dev->of_node,
224 "raspberrypi,firmware-clocks");
225 if (firmware) {
226 of_node_put(firmware);
227 return;
228 }
229
230 rpi_clk = platform_device_register_data(dev, "raspberrypi-clk",
231 -1, NULL, 0);
232}
233
234unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw, unsigned int id)
235{
236 struct rpi_firmware_clk_rate_request msg =
237 RPI_FIRMWARE_CLK_RATE_REQUEST(id);
238 int ret;
239
240 ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_MAX_CLOCK_RATE,
241 &msg, sizeof(msg));
242 if (ret)
243 /*
244 * If our firmware doesn't support that operation, or fails, we
245 * assume the maximum clock rate is absolute maximum we can
246 * store over our type.
247 */
248 return UINT_MAX;
249
250 return le32_to_cpu(msg.rate);
251}
252EXPORT_SYMBOL_GPL(rpi_firmware_clk_get_max_rate);
253
254static void rpi_firmware_delete(struct kref *kref)
255{
256 struct rpi_firmware *fw = container_of(kref, struct rpi_firmware,
257 consumers);
258
259 mbox_free_channel(fw->chan);
260 kfree(fw);
261}
262
263void rpi_firmware_put(struct rpi_firmware *fw)
264{
265 kref_put(&fw->consumers, rpi_firmware_delete);
266}
267EXPORT_SYMBOL_GPL(rpi_firmware_put);
268
269static void devm_rpi_firmware_put(void *data)
270{
271 struct rpi_firmware *fw = data;
272
273 rpi_firmware_put(fw);
274}
275
276static int rpi_firmware_probe(struct platform_device *pdev)
277{
278 struct device *dev = &pdev->dev;
279 struct rpi_firmware *fw;
280
281 /*
282 * Memory will be freed by rpi_firmware_delete() once all users have
283 * released their firmware handles. Don't use devm_kzalloc() here.
284 */
285 fw = kzalloc_obj(*fw);
286 if (!fw)
287 return -ENOMEM;
288
289 fw->cl.dev = dev;
290 fw->cl.rx_callback = response_callback;
291 fw->cl.tx_block = true;
292
293 fw->chan = mbox_request_channel(&fw->cl, 0);
294 if (IS_ERR(fw->chan)) {
295 int ret = PTR_ERR(fw->chan);
296 kfree(fw);
297 return dev_err_probe(dev, ret, "Failed to get mbox channel\n");
298 }
299
300 init_completion(&fw->c);
301 kref_init(&fw->consumers);
302
303 platform_set_drvdata(pdev, fw);
304
305 rpi_firmware_print_firmware_revision(fw);
306 rpi_register_hwmon_driver(dev, fw);
307 rpi_register_clk_driver(dev);
308
309 return 0;
310}
311
312static void rpi_firmware_shutdown(struct platform_device *pdev)
313{
314 struct rpi_firmware *fw = platform_get_drvdata(pdev);
315
316 if (!fw)
317 return;
318
319 rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);
320}
321
322static void rpi_firmware_remove(struct platform_device *pdev)
323{
324 struct rpi_firmware *fw = platform_get_drvdata(pdev);
325
326 platform_device_unregister(rpi_hwmon);
327 rpi_hwmon = NULL;
328 platform_device_unregister(rpi_clk);
329 rpi_clk = NULL;
330
331 rpi_firmware_put(fw);
332}
333
334static const struct of_device_id rpi_firmware_of_match[] = {
335 { .compatible = "raspberrypi,bcm2835-firmware", },
336 {},
337};
338MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
339
340struct device_node *rpi_firmware_find_node(void)
341{
342 return of_find_matching_node(NULL, rpi_firmware_of_match);
343}
344EXPORT_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 */
354struct 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
373err_put_device:
374 put_device(&pdev->dev);
375 return NULL;
376}
377EXPORT_SYMBOL_GPL(rpi_firmware_get);
378
379/**
380 * devm_rpi_firmware_get - Get pointer to rpi_firmware structure.
381 * @dev: The firmware device structure
382 * @firmware_node: Pointer to the firmware Device Tree node.
383 *
384 * Returns NULL is the firmware device is not ready.
385 */
386struct 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}
400EXPORT_SYMBOL_GPL(devm_rpi_firmware_get);
401
402static 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};
411module_platform_driver(rpi_firmware_driver);
412
413MODULE_AUTHOR("Eric Anholt <[email protected]>");
414MODULE_DESCRIPTION("Raspberry Pi firmware driver");
415MODULE_LICENSE("GPL v2");