summaryrefslogtreecommitdiff
path: root/drivers/i2c/busses/i2c-tegra-bpmp.c
blob: f6cd35d0a2ac0e6c37c3e9e982a20a2ee77df2fb (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
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
/*
 * drivers/i2c/busses/i2c-tegra-bpmp.c
 *
 * Copyright (c) 2016 NVIDIA Corporation.  All rights reserved.
 *
 * Author: Shardar Shariff Md <smohammed@nvidia.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>

#include <soc/tegra/bpmp-abi.h>
#include <soc/tegra/bpmp.h>

/*
 * Serialized I2C message header size is 6 bytes and includes address, flags
 * and length
 */
#define SERIALI2C_HDR_SIZE 6

struct tegra_bpmp_i2c {
	struct i2c_adapter adapter;
	struct device *dev;

	struct tegra_bpmp *bpmp;
	unsigned int bus;
};

/*
 * Linux flags are translated to BPMP defined I2C flags that are used in BPMP
 * firmware I2C driver to avoid any issues in future if Linux I2C flags are
 * changed.
 */
static int tegra_bpmp_xlate_flags(u16 flags, u16 *out)
{
	if (flags & I2C_M_TEN) {
		*out |= SERIALI2C_TEN;
		flags &= ~I2C_M_TEN;
	}

	if (flags & I2C_M_RD) {
		*out |= SERIALI2C_RD;
		flags &= ~I2C_M_RD;
	}

	if (flags & I2C_M_STOP) {
		*out |= SERIALI2C_STOP;
		flags &= ~I2C_M_STOP;
	}

	if (flags & I2C_M_NOSTART) {
		*out |= SERIALI2C_NOSTART;
		flags &= ~I2C_M_NOSTART;
	}

	if (flags & I2C_M_REV_DIR_ADDR) {
		*out |= SERIALI2C_REV_DIR_ADDR;
		flags &= ~I2C_M_REV_DIR_ADDR;
	}

	if (flags & I2C_M_IGNORE_NAK) {
		*out |= SERIALI2C_IGNORE_NAK;
		flags &= ~I2C_M_IGNORE_NAK;
	}

	if (flags & I2C_M_NO_RD_ACK) {
		*out |= SERIALI2C_NO_RD_ACK;
		flags &= ~I2C_M_NO_RD_ACK;
	}

	if (flags & I2C_M_RECV_LEN) {
		*out |= SERIALI2C_RECV_LEN;
		flags &= ~I2C_M_RECV_LEN;
	}

	return (flags != 0) ? -EINVAL : 0;
}

/**
 * The serialized I2C format is simply the following:
 * [addr little-endian][flags little-endian][len little-endian][data if write]
 * [addr little-endian][flags little-endian][len little-endian][data if write]
 *  ...
 *
 * The flags are translated from Linux kernel representation to seriali2c
 * representation. Any undefined flag being set causes an error.
 *
 * The data is there only for writes. Reads have the data transferred in the
 * other direction, and thus data is not present.
 *
 * See deserialize_i2c documentation for the data format in the other direction.
 */
static int tegra_bpmp_serialize_i2c_msg(struct tegra_bpmp_i2c *i2c,
					struct mrq_i2c_request *request,
					struct i2c_msg *msgs,
					unsigned int num)
{
	char *buf = request->xfer.data_buf;
	unsigned int i, j, pos = 0;
	int err;

	for (i = 0; i < num; i++) {
		struct i2c_msg *msg = &msgs[i];
		u16 flags = 0;

		err = tegra_bpmp_xlate_flags(msg->flags, &flags);
		if (err < 0)
			return err;

		buf[pos++] = msg->addr & 0xff;
		buf[pos++] = (msg->addr & 0xff00) >> 8;
		buf[pos++] = flags & 0xff;
		buf[pos++] = (flags & 0xff00) >> 8;
		buf[pos++] = msg->len & 0xff;
		buf[pos++] = (msg->len & 0xff00) >> 8;

		if ((flags & SERIALI2C_RD) == 0) {
			for (j = 0; j < msg->len; j++)
				buf[pos++] = msg->buf[j];
		}
	}

	request->xfer.data_size = pos;

	return 0;
}

/**
 * The data in the BPMP -> CPU direction is composed of sequential blocks for
 * those messages that have I2C_M_RD. So, for example, if you have:
 *
 * - !I2C_M_RD, len == 5, data == a0 01 02 03 04
 * - !I2C_M_RD, len == 1, data == a0
 * - I2C_M_RD, len == 2, data == [uninitialized buffer 1]
 * - !I2C_M_RD, len == 1, data == a2
 * - I2C_M_RD, len == 2, data == [uninitialized buffer 2]
 *
 * ...then the data in the BPMP -> CPU direction would be 4 bytes total, and
 * would contain 2 bytes that will go to uninitialized buffer 1, and 2 bytes
 * that will go to uninitialized buffer 2.
 */
static int tegra_bpmp_i2c_deserialize(struct tegra_bpmp_i2c *i2c,
				      struct mrq_i2c_response *response,
				      struct i2c_msg *msgs,
				      unsigned int num)
{
	size_t size = response->xfer.data_size, len = 0, pos = 0;
	char *buf = response->xfer.data_buf;
	unsigned int i;

	for (i = 0; i < num; i++)
		if (msgs[i].flags & I2C_M_RD)
			len += msgs[i].len;

	if (len != size)
		return -EINVAL;

	for (i = 0; i < num; i++) {
		if (msgs[i].flags & I2C_M_RD) {
			memcpy(msgs[i].buf, buf + pos, msgs[i].len);
			pos += msgs[i].len;
		}
	}

	return 0;
}

static int tegra_bpmp_i2c_msg_len_check(struct i2c_msg *msgs, unsigned int num)
{
	size_t tx_len = 0, rx_len = 0;
	unsigned int i;

	for (i = 0; i < num; i++)
		if (!(msgs[i].flags & I2C_M_RD))
			tx_len += SERIALI2C_HDR_SIZE + msgs[i].len;

	if (tx_len > TEGRA_I2C_IPC_MAX_IN_BUF_SIZE)
		return -EINVAL;

	for (i = 0; i < num; i++)
		if ((msgs[i].flags & I2C_M_RD))
			rx_len += msgs[i].len;

	if (rx_len > TEGRA_I2C_IPC_MAX_OUT_BUF_SIZE)
		return -EINVAL;

	return 0;
}

static int tegra_bpmp_i2c_msg_xfer(struct tegra_bpmp_i2c *i2c,
				   struct mrq_i2c_request *request,
				   struct mrq_i2c_response *response)
{
	struct tegra_bpmp_message msg;
	int err;

	request->cmd = CMD_I2C_XFER;
	request->xfer.bus_id = i2c->bus;

	memset(&msg, 0, sizeof(msg));
	msg.mrq = MRQ_I2C;
	msg.tx.data = request;
	msg.tx.size = sizeof(*request);
	msg.rx.data = response;
	msg.rx.size = sizeof(*response);

	if (irqs_disabled())
		err = tegra_bpmp_transfer_atomic(i2c->bpmp, &msg);
	else
		err = tegra_bpmp_transfer(i2c->bpmp, &msg);

	return err;
}

static int tegra_bpmp_i2c_xfer(struct i2c_adapter *adapter,
			       struct i2c_msg *msgs, int num)
{
	struct tegra_bpmp_i2c *i2c = i2c_get_adapdata(adapter);
	struct mrq_i2c_response response;
	struct mrq_i2c_request request;
	int err;

	err = tegra_bpmp_i2c_msg_len_check(msgs, num);
	if (err < 0) {
		dev_err(i2c->dev, "unsupported message length\n");
		return err;
	}

	memset(&request, 0, sizeof(request));
	memset(&response, 0, sizeof(response));

	err = tegra_bpmp_serialize_i2c_msg(i2c, &request, msgs, num);
	if (err < 0) {
		dev_err(i2c->dev, "failed to serialize message: %d\n", err);
		return err;
	}

	err = tegra_bpmp_i2c_msg_xfer(i2c, &request, &response);
	if (err < 0) {
		dev_err(i2c->dev, "failed to transfer message: %d\n", err);
		return err;
	}

	err = tegra_bpmp_i2c_deserialize(i2c, &response, msgs, num);
	if (err < 0) {
		dev_err(i2c->dev, "failed to deserialize message: %d\n", err);
		return err;
	}

	return num;
}

static u32 tegra_bpmp_i2c_func(struct i2c_adapter *adapter)
{
	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR |
	       I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_NOSTART;
}

static const struct i2c_algorithm tegra_bpmp_i2c_algo = {
	.master_xfer = tegra_bpmp_i2c_xfer,
	.functionality = tegra_bpmp_i2c_func,
};

static int tegra_bpmp_i2c_probe(struct platform_device *pdev)
{
	struct tegra_bpmp_i2c *i2c;
	u32 value;
	int err;

	i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
	if (!i2c)
		return -ENOMEM;

	i2c->dev = &pdev->dev;

	i2c->bpmp = dev_get_drvdata(pdev->dev.parent);
	if (!i2c->bpmp)
		return -ENODEV;

	err = of_property_read_u32(pdev->dev.of_node, "nvidia,bpmp-bus-id",
				   &value);
	if (err < 0)
		return err;

	i2c->bus = value;

	i2c_set_adapdata(&i2c->adapter, i2c);
	i2c->adapter.owner = THIS_MODULE;
	strlcpy(i2c->adapter.name, "Tegra BPMP I2C adapter",
		sizeof(i2c->adapter.name));
	i2c->adapter.algo = &tegra_bpmp_i2c_algo;
	i2c->adapter.dev.parent = &pdev->dev;
	i2c->adapter.dev.of_node = pdev->dev.of_node;

	platform_set_drvdata(pdev, i2c);

	return i2c_add_adapter(&i2c->adapter);
}

static int tegra_bpmp_i2c_remove(struct platform_device *pdev)
{
	struct tegra_bpmp_i2c *i2c = platform_get_drvdata(pdev);

	i2c_del_adapter(&i2c->adapter);

	return 0;
}

static const struct of_device_id tegra_bpmp_i2c_of_match[] = {
	{ .compatible = "nvidia,tegra186-bpmp-i2c", },
	{ }
};
MODULE_DEVICE_TABLE(of, tegra_bpmp_i2c_of_match);

static struct platform_driver tegra_bpmp_i2c_driver = {
	.driver = {
		.name = "tegra-bpmp-i2c",
		.of_match_table = tegra_bpmp_i2c_of_match,
	},
	.probe = tegra_bpmp_i2c_probe,
	.remove = tegra_bpmp_i2c_remove,
};
module_platform_driver(tegra_bpmp_i2c_driver);

MODULE_DESCRIPTION("NVIDIA Tegra BPMP I2C bus controller driver");
MODULE_AUTHOR("Shardar Shariff Md <smohammed@nvidia.com>");
MODULE_AUTHOR("Juha-Matti Tilli");
MODULE_LICENSE("GPL v2");