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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * ATMEL I2C TPM AT97SC3204T
4 *
5 * Copyright (C) 2012 V Lab Technologies
6 * Teddy Reed <teddy@prosauce.org>
7 * Copyright (C) 2013, Obsidian Research Corp.
8 * Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
9 * Device driver for ATMEL I2C TPMs.
10 *
11 * Teddy Reed determined the basic I2C command flow, unlike other I2C TPM
12 * devices the raw TCG formatted TPM command data is written via I2C and then
13 * raw TCG formatted TPM command data is returned via I2C.
14 *
15 * TGC status/locality/etc functions seen in the LPC implementation do not
16 * seem to be present.
17 */
18#include <linux/init.h>
19#include <linux/module.h>
20#include <linux/moduleparam.h>
21#include <linux/slab.h>
22#include <linux/i2c.h>
23#include "tpm.h"
24
25#define I2C_DRIVER_NAME "tpm_i2c_atmel"
26
27#define TPM_I2C_SHORT_TIMEOUT 750 /* ms */
28#define TPM_I2C_LONG_TIMEOUT 2000 /* 2 sec */
29
30#define ATMEL_STS_OK 1
31
32struct priv_data {
33 size_t len;
34 /* This is the amount we read on the first try. 25 was chosen to fit a
35 * fair number of read responses in the buffer so a 2nd retry can be
36 * avoided in small message cases. */
37 u8 buffer[sizeof(struct tpm_header) + 25];
38};
39
40static int i2c_atmel_send(struct tpm_chip *chip, u8 *buf, size_t len)
41{
42 struct priv_data *priv = dev_get_drvdata(&chip->dev);
43 struct i2c_client *client = to_i2c_client(chip->dev.parent);
44 s32 status;
45
46 priv->len = 0;
47
48 if (len <= 2)
49 return -EIO;
50
51 status = i2c_master_send(client, buf, len);
52
53 dev_dbg(&chip->dev,
54 "%s(buf=%*ph len=%0zx) -> sts=%d\n", __func__,
55 (int)min_t(size_t, 64, len), buf, len, status);
56
57 if (status < 0)
58 return status;
59
60 /* The upper layer does not support incomplete sends. */
61 if (status != len)
62 return -E2BIG;
63
64 return 0;
65}
66
67static int i2c_atmel_recv(struct tpm_chip *chip, u8 *buf, size_t count)
68{
69 struct priv_data *priv = dev_get_drvdata(&chip->dev);
70 struct i2c_client *client = to_i2c_client(chip->dev.parent);
71 struct tpm_header *hdr = (struct tpm_header *)priv->buffer;
72 u32 expected_len;
73 int rc;
74
75 if (priv->len == 0)
76 return -EIO;
77
78 /* Get the message size from the message header, if we didn't get the
79 * whole message in read_status then we need to re-read the
80 * message. */
81 expected_len = be32_to_cpu(hdr->length);
82 if (expected_len > count)
83 return -ENOMEM;
84
85 if (priv->len >= expected_len) {
86 dev_dbg(&chip->dev,
87 "%s early(buf=%*ph count=%0zx) -> ret=%d\n", __func__,
88 (int)min_t(size_t, 64, expected_len), buf, count,
89 expected_len);
90 memcpy(buf, priv->buffer, expected_len);
91 return expected_len;
92 }
93
94 rc = i2c_master_recv(client, buf, expected_len);
95 dev_dbg(&chip->dev,
96 "%s reread(buf=%*ph count=%0zx) -> ret=%d\n", __func__,
97 (int)min_t(size_t, 64, expected_len), buf, count,
98 expected_len);
99 return rc;
100}
101
102static void i2c_atmel_cancel(struct tpm_chip *chip)
103{
104 dev_err(&chip->dev, "TPM operation cancellation was requested, but is not supported");
105}
106
107static u8 i2c_atmel_read_status(struct tpm_chip *chip)
108{
109 struct priv_data *priv = dev_get_drvdata(&chip->dev);
110 struct i2c_client *client = to_i2c_client(chip->dev.parent);
111 int rc;
112
113 /* The TPM fails the I2C read until it is ready, so we do the entire
114 * transfer here and buffer it locally. This way the common code can
115 * properly handle the timeouts. */
116 priv->len = 0;
117 memset(priv->buffer, 0, sizeof(priv->buffer));
118
119
120 /* Once the TPM has completed the command the command remains readable
121 * until another command is issued. */
122 rc = i2c_master_recv(client, priv->buffer, sizeof(priv->buffer));
123 dev_dbg(&chip->dev,
124 "%s: sts=%d", __func__, rc);
125 if (rc <= 0)
126 return 0;
127
128 priv->len = rc;
129
130 return ATMEL_STS_OK;
131}
132
133static bool i2c_atmel_req_canceled(struct tpm_chip *chip, u8 status)
134{
135 return false;
136}
137
138static const struct tpm_class_ops i2c_atmel = {
139 .flags = TPM_OPS_AUTO_STARTUP,
140 .status = i2c_atmel_read_status,
141 .recv = i2c_atmel_recv,
142 .send = i2c_atmel_send,
143 .cancel = i2c_atmel_cancel,
144 .req_complete_mask = ATMEL_STS_OK,
145 .req_complete_val = ATMEL_STS_OK,
146 .req_canceled = i2c_atmel_req_canceled,
147};
148
149static int i2c_atmel_probe(struct i2c_client *client)
150{
151 struct tpm_chip *chip;
152 struct device *dev = &client->dev;
153 struct priv_data *priv;
154
155 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
156 return -ENODEV;
157
158 chip = tpmm_chip_alloc(dev, &i2c_atmel);
159 if (IS_ERR(chip))
160 return PTR_ERR(chip);
161
162 priv = devm_kzalloc(dev, sizeof(struct priv_data), GFP_KERNEL);
163 if (!priv)
164 return -ENOMEM;
165
166 /* Default timeouts */
167 chip->timeout_a = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
168 chip->timeout_b = msecs_to_jiffies(TPM_I2C_LONG_TIMEOUT);
169 chip->timeout_c = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
170 chip->timeout_d = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
171
172 dev_set_drvdata(&chip->dev, priv);
173
174 /* There is no known way to probe for this device, and all version
175 * information seems to be read via TPM commands. Thus we rely on the
176 * TPM startup process in the common code to detect the device. */
177
178 return tpm_chip_register(chip);
179}
180
181static void i2c_atmel_remove(struct i2c_client *client)
182{
183 struct device *dev = &(client->dev);
184 struct tpm_chip *chip = dev_get_drvdata(dev);
185 tpm_chip_unregister(chip);
186}
187
188static const struct i2c_device_id i2c_atmel_id[] = {
189 {I2C_DRIVER_NAME, 0},
190 {}
191};
192MODULE_DEVICE_TABLE(i2c, i2c_atmel_id);
193
194#ifdef CONFIG_OF
195static const struct of_device_id i2c_atmel_of_match[] = {
196 {.compatible = "atmel,at97sc3204t"},
197 {},
198};
199MODULE_DEVICE_TABLE(of, i2c_atmel_of_match);
200#endif
201
202static SIMPLE_DEV_PM_OPS(i2c_atmel_pm_ops, tpm_pm_suspend, tpm_pm_resume);
203
204static struct i2c_driver i2c_atmel_driver = {
205 .id_table = i2c_atmel_id,
206 .probe = i2c_atmel_probe,
207 .remove = i2c_atmel_remove,
208 .driver = {
209 .name = I2C_DRIVER_NAME,
210 .pm = &i2c_atmel_pm_ops,
211 .of_match_table = of_match_ptr(i2c_atmel_of_match),
212 },
213};
214
215module_i2c_driver(i2c_atmel_driver);
216
217MODULE_AUTHOR("Jason Gunthorpe <jgunthorpe@obsidianresearch.com>");
218MODULE_DESCRIPTION("Atmel TPM I2C Driver");
219MODULE_LICENSE("GPL");
1/*
2 * ATMEL I2C TPM AT97SC3204T
3 *
4 * Copyright (C) 2012 V Lab Technologies
5 * Teddy Reed <teddy@prosauce.org>
6 * Copyright (C) 2013, Obsidian Research Corp.
7 * Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
8 * Device driver for ATMEL I2C TPMs.
9 *
10 * Teddy Reed determined the basic I2C command flow, unlike other I2C TPM
11 * devices the raw TCG formatted TPM command data is written via I2C and then
12 * raw TCG formatted TPM command data is returned via I2C.
13 *
14 * TGC status/locality/etc functions seen in the LPC implementation do not
15 * seem to be present.
16 *
17 * This program is free software: you can redistribute it and/or modify
18 * it under the terms of the GNU General Public License as published by
19 * the Free Software Foundation, either version 2 of the License, or
20 * (at your option) any later version.
21 *
22 * This program is distributed in the hope that it will be useful,
23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 * GNU General Public License for more details.
26 *
27 * You should have received a copy of the GNU General Public License
28 * along with this program. If not, see http://www.gnu.org/licenses/>.
29 */
30#include <linux/init.h>
31#include <linux/module.h>
32#include <linux/moduleparam.h>
33#include <linux/slab.h>
34#include <linux/i2c.h>
35#include "tpm.h"
36
37#define I2C_DRIVER_NAME "tpm_i2c_atmel"
38
39#define TPM_I2C_SHORT_TIMEOUT 750 /* ms */
40#define TPM_I2C_LONG_TIMEOUT 2000 /* 2 sec */
41
42#define ATMEL_STS_OK 1
43
44struct priv_data {
45 size_t len;
46 /* This is the amount we read on the first try. 25 was chosen to fit a
47 * fair number of read responses in the buffer so a 2nd retry can be
48 * avoided in small message cases. */
49 u8 buffer[sizeof(struct tpm_output_header) + 25];
50};
51
52static int i2c_atmel_send(struct tpm_chip *chip, u8 *buf, size_t len)
53{
54 struct priv_data *priv = chip->vendor.priv;
55 struct i2c_client *client = to_i2c_client(chip->dev);
56 s32 status;
57
58 priv->len = 0;
59
60 if (len <= 2)
61 return -EIO;
62
63 status = i2c_master_send(client, buf, len);
64
65 dev_dbg(chip->dev,
66 "%s(buf=%*ph len=%0zx) -> sts=%d\n", __func__,
67 (int)min_t(size_t, 64, len), buf, len, status);
68 return status;
69}
70
71static int i2c_atmel_recv(struct tpm_chip *chip, u8 *buf, size_t count)
72{
73 struct priv_data *priv = chip->vendor.priv;
74 struct i2c_client *client = to_i2c_client(chip->dev);
75 struct tpm_output_header *hdr =
76 (struct tpm_output_header *)priv->buffer;
77 u32 expected_len;
78 int rc;
79
80 if (priv->len == 0)
81 return -EIO;
82
83 /* Get the message size from the message header, if we didn't get the
84 * whole message in read_status then we need to re-read the
85 * message. */
86 expected_len = be32_to_cpu(hdr->length);
87 if (expected_len > count)
88 return -ENOMEM;
89
90 if (priv->len >= expected_len) {
91 dev_dbg(chip->dev,
92 "%s early(buf=%*ph count=%0zx) -> ret=%d\n", __func__,
93 (int)min_t(size_t, 64, expected_len), buf, count,
94 expected_len);
95 memcpy(buf, priv->buffer, expected_len);
96 return expected_len;
97 }
98
99 rc = i2c_master_recv(client, buf, expected_len);
100 dev_dbg(chip->dev,
101 "%s reread(buf=%*ph count=%0zx) -> ret=%d\n", __func__,
102 (int)min_t(size_t, 64, expected_len), buf, count,
103 expected_len);
104 return rc;
105}
106
107static void i2c_atmel_cancel(struct tpm_chip *chip)
108{
109 dev_err(chip->dev, "TPM operation cancellation was requested, but is not supported");
110}
111
112static u8 i2c_atmel_read_status(struct tpm_chip *chip)
113{
114 struct priv_data *priv = chip->vendor.priv;
115 struct i2c_client *client = to_i2c_client(chip->dev);
116 int rc;
117
118 /* The TPM fails the I2C read until it is ready, so we do the entire
119 * transfer here and buffer it locally. This way the common code can
120 * properly handle the timeouts. */
121 priv->len = 0;
122 memset(priv->buffer, 0, sizeof(priv->buffer));
123
124
125 /* Once the TPM has completed the command the command remains readable
126 * until another command is issued. */
127 rc = i2c_master_recv(client, priv->buffer, sizeof(priv->buffer));
128 dev_dbg(chip->dev,
129 "%s: sts=%d", __func__, rc);
130 if (rc <= 0)
131 return 0;
132
133 priv->len = rc;
134
135 return ATMEL_STS_OK;
136}
137
138static bool i2c_atmel_req_canceled(struct tpm_chip *chip, u8 status)
139{
140 return false;
141}
142
143static const struct tpm_class_ops i2c_atmel = {
144 .status = i2c_atmel_read_status,
145 .recv = i2c_atmel_recv,
146 .send = i2c_atmel_send,
147 .cancel = i2c_atmel_cancel,
148 .req_complete_mask = ATMEL_STS_OK,
149 .req_complete_val = ATMEL_STS_OK,
150 .req_canceled = i2c_atmel_req_canceled,
151};
152
153static int i2c_atmel_probe(struct i2c_client *client,
154 const struct i2c_device_id *id)
155{
156 int rc;
157 struct tpm_chip *chip;
158 struct device *dev = &client->dev;
159
160 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
161 return -ENODEV;
162
163 chip = tpm_register_hardware(dev, &i2c_atmel);
164 if (!chip) {
165 dev_err(dev, "%s() error in tpm_register_hardware\n", __func__);
166 return -ENODEV;
167 }
168
169 chip->vendor.priv = devm_kzalloc(dev, sizeof(struct priv_data),
170 GFP_KERNEL);
171
172 /* Default timeouts */
173 chip->vendor.timeout_a = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
174 chip->vendor.timeout_b = msecs_to_jiffies(TPM_I2C_LONG_TIMEOUT);
175 chip->vendor.timeout_c = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
176 chip->vendor.timeout_d = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
177 chip->vendor.irq = 0;
178
179 /* There is no known way to probe for this device, and all version
180 * information seems to be read via TPM commands. Thus we rely on the
181 * TPM startup process in the common code to detect the device. */
182 if (tpm_get_timeouts(chip)) {
183 rc = -ENODEV;
184 goto out_err;
185 }
186
187 if (tpm_do_selftest(chip)) {
188 rc = -ENODEV;
189 goto out_err;
190 }
191
192 return 0;
193
194out_err:
195 tpm_dev_vendor_release(chip);
196 tpm_remove_hardware(chip->dev);
197 return rc;
198}
199
200static int i2c_atmel_remove(struct i2c_client *client)
201{
202 struct device *dev = &(client->dev);
203 struct tpm_chip *chip = dev_get_drvdata(dev);
204
205 if (chip)
206 tpm_dev_vendor_release(chip);
207 tpm_remove_hardware(dev);
208 kfree(chip);
209 return 0;
210}
211
212static const struct i2c_device_id i2c_atmel_id[] = {
213 {I2C_DRIVER_NAME, 0},
214 {}
215};
216MODULE_DEVICE_TABLE(i2c, i2c_atmel_id);
217
218#ifdef CONFIG_OF
219static const struct of_device_id i2c_atmel_of_match[] = {
220 {.compatible = "atmel,at97sc3204t"},
221 {},
222};
223MODULE_DEVICE_TABLE(of, i2c_atmel_of_match);
224#endif
225
226static SIMPLE_DEV_PM_OPS(i2c_atmel_pm_ops, tpm_pm_suspend, tpm_pm_resume);
227
228static struct i2c_driver i2c_atmel_driver = {
229 .id_table = i2c_atmel_id,
230 .probe = i2c_atmel_probe,
231 .remove = i2c_atmel_remove,
232 .driver = {
233 .name = I2C_DRIVER_NAME,
234 .owner = THIS_MODULE,
235 .pm = &i2c_atmel_pm_ops,
236 .of_match_table = of_match_ptr(i2c_atmel_of_match),
237 },
238};
239
240module_i2c_driver(i2c_atmel_driver);
241
242MODULE_AUTHOR("Jason Gunthorpe <jgunthorpe@obsidianresearch.com>");
243MODULE_DESCRIPTION("Atmel TPM I2C Driver");
244MODULE_LICENSE("GPL");