summaryrefslogtreecommitdiffstats
path: root/drivers/char/tpm/tpm_tis_spi_main.c
blob: aaa59a00eeaefb05d1ab99e762664d6fad4bcbfd (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2015 Infineon Technologies AG
 * Copyright (C) 2016 STMicroelectronics SAS
 *
 * Authors:
 * Peter Huewe <peter.huewe@infineon.com>
 * Christophe Ricard <christophe-h.ricard@st.com>
 *
 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
 *
 * Device driver for TCG/TCPA TPM (trusted platform module).
 * Specifications at www.trustedcomputinggroup.org
 *
 * This device driver implements the TPM interface as defined in
 * the TCG TPM Interface Spec version 1.3, revision 27 via _raw/native
 * SPI access_.
 *
 * It is based on the original tpm_tis device driver from Leendert van
 * Dorn and Kyleen Hall and Jarko Sakkinnen.
 */

#include <linux/acpi.h>
#include <linux/completion.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>

#include <linux/of_device.h>
#include <linux/spi/spi.h>
#include <linux/tpm.h>

#include "tpm.h"
#include "tpm_tis_core.h"
#include "tpm_tis_spi.h"

#define MAX_SPI_FRAMESIZE 64

/*
 * TCG SPI flow control is documented in section 6.4 of the spec[1]. In short,
 * keep trying to read from the device until MISO goes high indicating the
 * wait state has ended.
 *
 * [1] https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
 */
static int tpm_tis_spi_flow_control(struct tpm_tis_spi_phy *phy,
				    struct spi_transfer *spi_xfer)
{
	struct spi_message m;
	int ret, i;

	if ((phy->iobuf[3] & 0x01) == 0) {
		// handle SPI wait states
		for (i = 0; i < TPM_RETRY; i++) {
			spi_xfer->len = 1;
			spi_message_init(&m);
			spi_message_add_tail(spi_xfer, &m);
			ret = spi_sync_locked(phy->spi_device, &m);
			if (ret < 0)
				return ret;
			if (phy->iobuf[0] & 0x01)
				break;
		}

		if (i == TPM_RETRY)
			return -ETIMEDOUT;
	}

	return 0;
}

int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
			 u8 *in, const u8 *out)
{
	struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
	int ret = 0;
	struct spi_message m;
	struct spi_transfer spi_xfer;
	u8 transfer_len;

	spi_bus_lock(phy->spi_device->master);

	while (len) {
		transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);

		phy->iobuf[0] = (in ? 0x80 : 0) | (transfer_len - 1);
		phy->iobuf[1] = 0xd4;
		phy->iobuf[2] = addr >> 8;
		phy->iobuf[3] = addr;

		memset(&spi_xfer, 0, sizeof(spi_xfer));
		spi_xfer.tx_buf = phy->iobuf;
		spi_xfer.rx_buf = phy->iobuf;
		spi_xfer.len = 4;
		spi_xfer.cs_change = 1;

		spi_message_init(&m);
		spi_message_add_tail(&spi_xfer, &m);
		ret = spi_sync_locked(phy->spi_device, &m);
		if (ret < 0)
			goto exit;

		/* Flow control transfers are receive only */
		spi_xfer.tx_buf = NULL;
		ret = phy->flow_control(phy, &spi_xfer);
		if (ret < 0)
			goto exit;

		spi_xfer.cs_change = 0;
		spi_xfer.len = transfer_len;
		spi_xfer.delay.value = 5;
		spi_xfer.delay.unit = SPI_DELAY_UNIT_USECS;

		if (out) {
			spi_xfer.tx_buf = phy->iobuf;
			spi_xfer.rx_buf = NULL;
			memcpy(phy->iobuf, out, transfer_len);
			out += transfer_len;
		}

		spi_message_init(&m);
		spi_message_add_tail(&spi_xfer, &m);
		reinit_completion(&phy->ready);
		ret = spi_sync_locked(phy->spi_device, &m);
		if (ret < 0)
			goto exit;

		if (in) {
			memcpy(in, phy->iobuf, transfer_len);
			in += transfer_len;
		}

		len -= transfer_len;
	}

exit:
	spi_bus_unlock(phy->spi_device->master);
	return ret;
}

static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,
				  u16 len, u8 *result)
{
	return tpm_tis_spi_transfer(data, addr, len, result, NULL);
}

static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,
				   u16 len, const u8 *value)
{
	return tpm_tis_spi_transfer(data, addr, len, NULL, value);
}

int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result)
{
	__le16 result_le;
	int rc;

	rc = data->phy_ops->read_bytes(data, addr, sizeof(u16),
				       (u8 *)&result_le);
	if (!rc)
		*result = le16_to_cpu(result_le);

	return rc;
}

int tpm_tis_spi_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
{
	__le32 result_le;
	int rc;

	rc = data->phy_ops->read_bytes(data, addr, sizeof(u32),
				       (u8 *)&result_le);
	if (!rc)
		*result = le32_to_cpu(result_le);

	return rc;
}

int tpm_tis_spi_write32(struct tpm_tis_data *data, u32 addr, u32 value)
{
	__le32 value_le;
	int rc;

	value_le = cpu_to_le32(value);
	rc = data->phy_ops->write_bytes(data, addr, sizeof(u32),
					(u8 *)&value_le);

	return rc;
}

int tpm_tis_spi_init(struct spi_device *spi, struct tpm_tis_spi_phy *phy,
		     int irq, const struct tpm_tis_phy_ops *phy_ops)
{
	phy->iobuf = devm_kmalloc(&spi->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL);
	if (!phy->iobuf)
		return -ENOMEM;

	phy->spi_device = spi;

	return tpm_tis_core_init(&spi->dev, &phy->priv, irq, phy_ops, NULL);
}

static const struct tpm_tis_phy_ops tpm_spi_phy_ops = {
	.read_bytes = tpm_tis_spi_read_bytes,
	.write_bytes = tpm_tis_spi_write_bytes,
	.read16 = tpm_tis_spi_read16,
	.read32 = tpm_tis_spi_read32,
	.write32 = tpm_tis_spi_write32,
};

static int tpm_tis_spi_probe(struct spi_device *dev)
{
	struct tpm_tis_spi_phy *phy;
	int irq;

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

	phy->flow_control = tpm_tis_spi_flow_control;

	/* If the SPI device has an IRQ then use that */
	if (dev->irq > 0)
		irq = dev->irq;
	else
		irq = -1;

	init_completion(&phy->ready);
	return tpm_tis_spi_init(dev, phy, irq, &tpm_spi_phy_ops);
}

typedef int (*tpm_tis_spi_probe_func)(struct spi_device *);

static int tpm_tis_spi_driver_probe(struct spi_device *spi)
{
	const struct spi_device_id *spi_dev_id = spi_get_device_id(spi);
	tpm_tis_spi_probe_func probe_func;

	probe_func = of_device_get_match_data(&spi->dev);
	if (!probe_func) {
		if (spi_dev_id) {
			probe_func = (tpm_tis_spi_probe_func)spi_dev_id->driver_data;
			if (!probe_func)
				return -ENODEV;
		} else
			probe_func = tpm_tis_spi_probe;
	}

	return probe_func(spi);
}

static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_spi_resume);

static int tpm_tis_spi_remove(struct spi_device *dev)
{
	struct tpm_chip *chip = spi_get_drvdata(dev);

	tpm_chip_unregister(chip);
	tpm_tis_remove(chip);
	return 0;
}

static const struct spi_device_id tpm_tis_spi_id[] = {
	{ "st33htpm-spi", (unsigned long)tpm_tis_spi_probe },
	{ "slb9670", (unsigned long)tpm_tis_spi_probe },
	{ "tpm_tis_spi", (unsigned long)tpm_tis_spi_probe },
	{ "tpm_tis-spi", (unsigned long)tpm_tis_spi_probe },
	{ "cr50", (unsigned long)cr50_spi_probe },
	{}
};
MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);

static const struct of_device_id of_tis_spi_match[] = {
	{ .compatible = "st,st33htpm-spi", .data = tpm_tis_spi_probe },
	{ .compatible = "infineon,slb9670", .data = tpm_tis_spi_probe },
	{ .compatible = "tcg,tpm_tis-spi", .data = tpm_tis_spi_probe },
	{ .compatible = "google,cr50", .data = cr50_spi_probe },
	{}
};
MODULE_DEVICE_TABLE(of, of_tis_spi_match);

static const struct acpi_device_id acpi_tis_spi_match[] = {
	{"SMO0768", 0},
	{}
};
MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match);

static struct spi_driver tpm_tis_spi_driver = {
	.driver = {
		.name = "tpm_tis_spi",
		.pm = &tpm_tis_pm,
		.of_match_table = of_match_ptr(of_tis_spi_match),
		.acpi_match_table = ACPI_PTR(acpi_tis_spi_match),
		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
	},
	.probe = tpm_tis_spi_driver_probe,
	.remove = tpm_tis_spi_remove,
	.id_table = tpm_tis_spi_id,
};
module_spi_driver(tpm_tis_spi_driver);

MODULE_DESCRIPTION("TPM Driver for native SPI access");
MODULE_LICENSE("GPL");