summaryrefslogtreecommitdiffstats
path: root/drivers/char/tpm/st33zp24/spi.c
blob: 5149231f3de28bc54c455b90479f59689294bd64 (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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * STMicroelectronics TPM SPI Linux driver for TPM ST33ZP24
 * Copyright (C) 2009 - 2016 STMicroelectronics
 */

#include <linux/module.h>
#include <linux/spi/spi.h>
#include <linux/of.h>
#include <linux/acpi.h>
#include <linux/tpm.h>

#include "../tpm.h"
#include "st33zp24.h"

#define TPM_DATA_FIFO           0x24
#define TPM_INTF_CAPABILITY     0x14

#define TPM_DUMMY_BYTE		0x00

#define MAX_SPI_LATENCY		15
#define LOCALITY0		0

#define ST33ZP24_OK					0x5A
#define ST33ZP24_UNDEFINED_ERR				0x80
#define ST33ZP24_BADLOCALITY				0x81
#define ST33ZP24_TISREGISTER_UNKNOWN			0x82
#define ST33ZP24_LOCALITY_NOT_ACTIVATED			0x83
#define ST33ZP24_HASH_END_BEFORE_HASH_START		0x84
#define ST33ZP24_BAD_COMMAND_ORDER			0x85
#define ST33ZP24_INCORECT_RECEIVED_LENGTH		0x86
#define ST33ZP24_TPM_FIFO_OVERFLOW			0x89
#define ST33ZP24_UNEXPECTED_READ_FIFO			0x8A
#define ST33ZP24_UNEXPECTED_WRITE_FIFO			0x8B
#define ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END	0x90
#define ST33ZP24_DUMMY_BYTES				0x00

/*
 * TPM command can be up to 2048 byte, A TPM response can be up to
 * 1024 byte.
 * Between command and response, there are latency byte (up to 15
 * usually on st33zp24 2 are enough).
 *
 * Overall when sending a command and expecting an answer we need if
 * worst case:
 * 2048 (for the TPM command) + 1024 (for the TPM answer).  We need
 * some latency byte before the answer is available (max 15).
 * We have 2048 + 1024 + 15.
 */
#define ST33ZP24_SPI_BUFFER_SIZE (ST33ZP24_BUFSIZE + (ST33ZP24_BUFSIZE / 2) +\
				  MAX_SPI_LATENCY)


struct st33zp24_spi_phy {
	struct spi_device *spi_device;

	u8 tx_buf[ST33ZP24_SPI_BUFFER_SIZE];
	u8 rx_buf[ST33ZP24_SPI_BUFFER_SIZE];

	int latency;
};

static int st33zp24_status_to_errno(u8 code)
{
	switch (code) {
	case ST33ZP24_OK:
		return 0;
	case ST33ZP24_UNDEFINED_ERR:
	case ST33ZP24_BADLOCALITY:
	case ST33ZP24_TISREGISTER_UNKNOWN:
	case ST33ZP24_LOCALITY_NOT_ACTIVATED:
	case ST33ZP24_HASH_END_BEFORE_HASH_START:
	case ST33ZP24_BAD_COMMAND_ORDER:
	case ST33ZP24_UNEXPECTED_READ_FIFO:
	case ST33ZP24_UNEXPECTED_WRITE_FIFO:
	case ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END:
		return -EPROTO;
	case ST33ZP24_INCORECT_RECEIVED_LENGTH:
	case ST33ZP24_TPM_FIFO_OVERFLOW:
		return -EMSGSIZE;
	case ST33ZP24_DUMMY_BYTES:
		return -ENOSYS;
	}
	return code;
}

/*
 * st33zp24_spi_send
 * Send byte to the TIS register according to the ST33ZP24 SPI protocol.
 * @param: phy_id, the phy description
 * @param: tpm_register, the tpm tis register where the data should be written
 * @param: tpm_data, the tpm_data to write inside the tpm_register
 * @param: tpm_size, The length of the data
 * @return: should be zero if success else a negative error code.
 */
static int st33zp24_spi_send(void *phy_id, u8 tpm_register, u8 *tpm_data,
			     int tpm_size)
{
	int total_length = 0, ret = 0;
	struct st33zp24_spi_phy *phy = phy_id;
	struct spi_device *dev = phy->spi_device;
	struct spi_transfer spi_xfer = {
		.tx_buf = phy->tx_buf,
		.rx_buf = phy->rx_buf,
	};

	/* Pre-Header */
	phy->tx_buf[total_length++] = TPM_WRITE_DIRECTION | LOCALITY0;
	phy->tx_buf[total_length++] = tpm_register;

	if (tpm_size > 0 && tpm_register == TPM_DATA_FIFO) {
		phy->tx_buf[total_length++] = tpm_size >> 8;
		phy->tx_buf[total_length++] = tpm_size;
	}

	memcpy(&phy->tx_buf[total_length], tpm_data, tpm_size);
	total_length += tpm_size;

	memset(&phy->tx_buf[total_length], TPM_DUMMY_BYTE, phy->latency);

	spi_xfer.len = total_length + phy->latency;

	ret = spi_sync_transfer(dev, &spi_xfer, 1);
	if (ret == 0)
		ret = phy->rx_buf[total_length + phy->latency - 1];

	return st33zp24_status_to_errno(ret);
} /* st33zp24_spi_send() */

/*
 * st33zp24_spi_read8_recv
 * Recv byte from the TIS register according to the ST33ZP24 SPI protocol.
 * @param: phy_id, the phy description
 * @param: tpm_register, the tpm tis register where the data should be read
 * @param: tpm_data, the TPM response
 * @param: tpm_size, tpm TPM response size to read.
 * @return: should be zero if success else a negative error code.
 */
static int st33zp24_spi_read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data,
				  int tpm_size)
{
	int total_length = 0, ret;
	struct st33zp24_spi_phy *phy = phy_id;
	struct spi_device *dev = phy->spi_device;
	struct spi_transfer spi_xfer = {
		.tx_buf = phy->tx_buf,
		.rx_buf = phy->rx_buf,
	};

	/* Pre-Header */
	phy->tx_buf[total_length++] = LOCALITY0;
	phy->tx_buf[total_length++] = tpm_register;

	memset(&phy->tx_buf[total_length], TPM_DUMMY_BYTE,
	       phy->latency + tpm_size);

	spi_xfer.len = total_length + phy->latency + tpm_size;

	/* header + status byte + size of the data + status byte */
	ret = spi_sync_transfer(dev, &spi_xfer, 1);
	if (tpm_size > 0 && ret == 0) {
		ret = phy->rx_buf[total_length + phy->latency - 1];

		memcpy(tpm_data, phy->rx_buf + total_length + phy->latency,
		       tpm_size);
	}

	return ret;
} /* st33zp24_spi_read8_reg() */

/*
 * st33zp24_spi_recv
 * Recv byte from the TIS register according to the ST33ZP24 SPI protocol.
 * @param: phy_id, the phy description
 * @param: tpm_register, the tpm tis register where the data should be read
 * @param: tpm_data, the TPM response
 * @param: tpm_size, tpm TPM response size to read.
 * @return: number of byte read successfully: should be one if success.
 */
static int st33zp24_spi_recv(void *phy_id, u8 tpm_register, u8 *tpm_data,
			     int tpm_size)
{
	int ret;

	ret = st33zp24_spi_read8_reg(phy_id, tpm_register, tpm_data, tpm_size);
	if (!st33zp24_status_to_errno(ret))
		return tpm_size;
	return ret;
} /* st33zp24_spi_recv() */

static int st33zp24_spi_evaluate_latency(void *phy_id)
{
	struct st33zp24_spi_phy *phy = phy_id;
	int latency = 1, status = 0;
	u8 data = 0;

	while (!status && latency < MAX_SPI_LATENCY) {
		phy->latency = latency;
		status = st33zp24_spi_read8_reg(phy_id, TPM_INTF_CAPABILITY,
						&data, 1);
		latency++;
	}
	if (status < 0)
		return status;
	if (latency == MAX_SPI_LATENCY)
		return -ENODEV;

	return latency - 1;
} /* evaluate_latency() */

static const struct st33zp24_phy_ops spi_phy_ops = {
	.send = st33zp24_spi_send,
	.recv = st33zp24_spi_recv,
};

/*
 * st33zp24_spi_probe initialize the TPM device
 * @param: dev, the spi_device description (TPM SPI description).
 * @return: 0 in case of success.
 *	 or a negative value describing the error.
 */
static int st33zp24_spi_probe(struct spi_device *dev)
{
	struct st33zp24_spi_phy *phy;

	phy = devm_kzalloc(&dev->dev, sizeof(struct st33zp24_spi_phy),
			   GFP_KERNEL);
	if (!phy)
		return -ENOMEM;

	phy->spi_device = dev;

	phy->latency = st33zp24_spi_evaluate_latency(phy);
	if (phy->latency <= 0)
		return -ENODEV;

	return st33zp24_probe(phy, &spi_phy_ops, &dev->dev, dev->irq);
}

/*
 * st33zp24_spi_remove remove the TPM device
 * @param: client, the spi_device description (TPM SPI description).
 * @return: 0 in case of success.
 */
static void st33zp24_spi_remove(struct spi_device *dev)
{
	struct tpm_chip *chip = spi_get_drvdata(dev);

	st33zp24_remove(chip);
}

static const struct spi_device_id st33zp24_spi_id[] = {
	{TPM_ST33_SPI, 0},
	{}
};
MODULE_DEVICE_TABLE(spi, st33zp24_spi_id);

static const struct of_device_id of_st33zp24_spi_match[] __maybe_unused = {
	{ .compatible = "st,st33zp24-spi", },
	{}
};
MODULE_DEVICE_TABLE(of, of_st33zp24_spi_match);

static const struct acpi_device_id st33zp24_spi_acpi_match[] __maybe_unused = {
	{"SMO3324"},
	{}
};
MODULE_DEVICE_TABLE(acpi, st33zp24_spi_acpi_match);

static SIMPLE_DEV_PM_OPS(st33zp24_spi_ops, st33zp24_pm_suspend,
			 st33zp24_pm_resume);

static struct spi_driver st33zp24_spi_driver = {
	.driver = {
		.name = "st33zp24-spi",
		.pm = &st33zp24_spi_ops,
		.of_match_table = of_match_ptr(of_st33zp24_spi_match),
		.acpi_match_table = ACPI_PTR(st33zp24_spi_acpi_match),
	},
	.probe = st33zp24_spi_probe,
	.remove = st33zp24_spi_remove,
	.id_table = st33zp24_spi_id,
};

module_spi_driver(st33zp24_spi_driver);

MODULE_AUTHOR("TPM support <TPMsupport@list.st.com>");
MODULE_DESCRIPTION("STM TPM 1.2 SPI ST33 Driver");
MODULE_VERSION("1.3.0");
MODULE_LICENSE("GPL");