summaryrefslogtreecommitdiff
path: root/drivers/firmware/raspberrypi.c
blob: 44eb99807e337c20b6e72c7ec712593ea85629dd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
/*
 * Defines interfaces for interacting wtih the Raspberry Pi firmware's
 * property channel.
 *
 * Copyright © 2015 Broadcom
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/dma-mapping.h>
#include <linux/mailbox_client.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <soc/bcm2835/raspberrypi-firmware.h>

#define MBOX_MSG(chan, data28)		(((data28) & ~0xf) | ((chan) & 0xf))
#define MBOX_CHAN(msg)			((msg) & 0xf)
#define MBOX_DATA28(msg)		((msg) & ~0xf)
#define MBOX_CHAN_PROPERTY		8

static struct platform_device *rpi_hwmon;

struct rpi_firmware {
	struct mbox_client cl;
	struct mbox_chan *chan; /* The property channel. */
	struct completion c;
	u32 enabled;
};

static DEFINE_MUTEX(transaction_lock);

static void response_callback(struct mbox_client *cl, void *msg)
{
	struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl);
	complete(&fw->c);
}

/*
 * Sends a request to the firmware through the BCM2835 mailbox driver,
 * and synchronously waits for the reply.
 */
static int
rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data)
{
	u32 message = MBOX_MSG(chan, data);
	int ret;

	WARN_ON(data & 0xf);

	mutex_lock(&transaction_lock);
	reinit_completion(&fw->c);
	ret = mbox_send_message(fw->chan, &message);
	if (ret >= 0) {
		wait_for_completion(&fw->c);
		ret = 0;
	} else {
		dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
	}
	mutex_unlock(&transaction_lock);

	return ret;
}

/**
 * rpi_firmware_property_list - Submit firmware property list
 * @fw:		Pointer to firmware structure from rpi_firmware_get().
 * @data:	Buffer holding tags.
 * @tag_size:	Size of tags buffer.
 *
 * Submits a set of concatenated tags to the VPU firmware through the
 * mailbox property interface.
 *
 * The buffer header and the ending tag are added by this function and
 * don't need to be supplied, just the actual tags for your operation.
 * See struct rpi_firmware_property_tag_header for the per-tag
 * structure.
 */
int rpi_firmware_property_list(struct rpi_firmware *fw,
			       void *data, size_t tag_size)
{
	size_t size = tag_size + 12;
	u32 *buf;
	dma_addr_t bus_addr;
	int ret;

	/* Packets are processed a dword at a time. */
	if (size & 3)
		return -EINVAL;

	buf = dma_alloc_coherent(fw->cl.dev, PAGE_ALIGN(size), &bus_addr,
				 GFP_ATOMIC);
	if (!buf)
		return -ENOMEM;

	/* The firmware will error out without parsing in this case. */
	WARN_ON(size >= 1024 * 1024);

	buf[0] = size;
	buf[1] = RPI_FIRMWARE_STATUS_REQUEST;
	memcpy(&buf[2], data, tag_size);
	buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END;
	wmb();

	ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr);

	rmb();
	memcpy(data, &buf[2], tag_size);
	if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) {
		/*
		 * The tag name here might not be the one causing the
		 * error, if there were multiple tags in the request.
		 * But single-tag is the most common, so go with it.
		 */
		dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",
			buf[2], buf[1]);
		ret = -EINVAL;
	}

	dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr);

	return ret;
}
EXPORT_SYMBOL_GPL(rpi_firmware_property_list);

/**
 * rpi_firmware_property - Submit single firmware property
 * @fw:		Pointer to firmware structure from rpi_firmware_get().
 * @tag:	One of enum_mbox_property_tag.
 * @tag_data:	Tag data buffer.
 * @buf_size:	Buffer size.
 *
 * Submits a single tag to the VPU firmware through the mailbox
 * property interface.
 *
 * This is a convenience wrapper around
 * rpi_firmware_property_list() to avoid some of the
 * boilerplate in property calls.
 */
int rpi_firmware_property(struct rpi_firmware *fw,
			  u32 tag, void *tag_data, size_t buf_size)
{
	struct rpi_firmware_property_tag_header *header;
	int ret;

	/* Some mailboxes can use over 1k bytes. Rather than checking
	 * size and using stack or kmalloc depending on requirements,
	 * just use kmalloc. Mailboxes don't get called enough to worry
	 * too much about the time taken in the allocation.
	 */
	void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL);

	if (!data)
		return -ENOMEM;

	header = data;
	header->tag = tag;
	header->buf_size = buf_size;
	header->req_resp_size = 0;
	memcpy(data + sizeof(*header), tag_data, buf_size);

	ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header));

	memcpy(tag_data, data + sizeof(*header), buf_size);

	kfree(data);

	return ret;
}
EXPORT_SYMBOL_GPL(rpi_firmware_property);

static void
rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
{
	u32 packet;
	int ret = rpi_firmware_property(fw,
					RPI_FIRMWARE_GET_FIRMWARE_REVISION,
					&packet, sizeof(packet));

	if (ret == 0) {
		struct tm tm;

		time64_to_tm(packet, 0, &tm);

		dev_info(fw->cl.dev,
			 "Attached to firmware from %04ld-%02d-%02d %02d:%02d\n",
			 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
			 tm.tm_hour, tm.tm_min);
	}
}

static void
rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw)
{
	u32 packet;
	int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED,
					&packet, sizeof(packet));

	if (ret)
		return;

	rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon",
						  -1, NULL, 0);
}

static int rpi_firmware_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct rpi_firmware *fw;

	fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL);
	if (!fw)
		return -ENOMEM;

	fw->cl.dev = dev;
	fw->cl.rx_callback = response_callback;
	fw->cl.tx_block = true;

	fw->chan = mbox_request_channel(&fw->cl, 0);
	if (IS_ERR(fw->chan)) {
		int ret = PTR_ERR(fw->chan);
		if (ret != -EPROBE_DEFER)
			dev_err(dev, "Failed to get mbox channel: %d\n", ret);
		return ret;
	}

	init_completion(&fw->c);

	platform_set_drvdata(pdev, fw);

	rpi_firmware_print_firmware_revision(fw);
	rpi_register_hwmon_driver(dev, fw);

	return 0;
}

static int rpi_firmware_remove(struct platform_device *pdev)
{
	struct rpi_firmware *fw = platform_get_drvdata(pdev);

	platform_device_unregister(rpi_hwmon);
	rpi_hwmon = NULL;
	mbox_free_channel(fw->chan);

	return 0;
}

/**
 * rpi_firmware_get - Get pointer to rpi_firmware structure.
 * @firmware_node:    Pointer to the firmware Device Tree node.
 *
 * Returns NULL is the firmware device is not ready.
 */
struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
{
	struct platform_device *pdev = of_find_device_by_node(firmware_node);

	if (!pdev)
		return NULL;

	return platform_get_drvdata(pdev);
}
EXPORT_SYMBOL_GPL(rpi_firmware_get);

static const struct of_device_id rpi_firmware_of_match[] = {
	{ .compatible = "raspberrypi,bcm2835-firmware", },
	{},
};
MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);

static struct platform_driver rpi_firmware_driver = {
	.driver = {
		.name = "raspberrypi-firmware",
		.of_match_table = rpi_firmware_of_match,
	},
	.probe		= rpi_firmware_probe,
	.remove		= rpi_firmware_remove,
};
module_platform_driver(rpi_firmware_driver);

MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
MODULE_DESCRIPTION("Raspberry Pi firmware driver");
MODULE_LICENSE("GPL v2");