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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
40#define TPM_I2C_LONG_TIMEOUT 2000
41
42#define ATMEL_STS_OK 1
43
44struct priv_data {
45 size_t len;
46
47
48
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 = dev_get_drvdata(&chip->dev);
55 struct i2c_client *client = to_i2c_client(chip->dev.parent);
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 = dev_get_drvdata(&chip->dev);
74 struct i2c_client *client = to_i2c_client(chip->dev.parent);
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
84
85
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 = dev_get_drvdata(&chip->dev);
115 struct i2c_client *client = to_i2c_client(chip->dev.parent);
116 int rc;
117
118
119
120
121 priv->len = 0;
122 memset(priv->buffer, 0, sizeof(priv->buffer));
123
124
125
126
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 .flags = TPM_OPS_AUTO_STARTUP,
145 .status = i2c_atmel_read_status,
146 .recv = i2c_atmel_recv,
147 .send = i2c_atmel_send,
148 .cancel = i2c_atmel_cancel,
149 .req_complete_mask = ATMEL_STS_OK,
150 .req_complete_val = ATMEL_STS_OK,
151 .req_canceled = i2c_atmel_req_canceled,
152};
153
154static int i2c_atmel_probe(struct i2c_client *client,
155 const struct i2c_device_id *id)
156{
157 struct tpm_chip *chip;
158 struct device *dev = &client->dev;
159 struct priv_data *priv;
160
161 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
162 return -ENODEV;
163
164 chip = tpmm_chip_alloc(dev, &i2c_atmel);
165 if (IS_ERR(chip))
166 return PTR_ERR(chip);
167
168 priv = devm_kzalloc(dev, sizeof(struct priv_data), GFP_KERNEL);
169 if (!priv)
170 return -ENOMEM;
171
172
173 chip->timeout_a = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
174 chip->timeout_b = msecs_to_jiffies(TPM_I2C_LONG_TIMEOUT);
175 chip->timeout_c = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
176 chip->timeout_d = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
177
178 dev_set_drvdata(&chip->dev, priv);
179
180
181
182
183
184 return tpm_chip_register(chip);
185}
186
187static int i2c_atmel_remove(struct i2c_client *client)
188{
189 struct device *dev = &(client->dev);
190 struct tpm_chip *chip = dev_get_drvdata(dev);
191 tpm_chip_unregister(chip);
192 return 0;
193}
194
195static const struct i2c_device_id i2c_atmel_id[] = {
196 {I2C_DRIVER_NAME, 0},
197 {}
198};
199MODULE_DEVICE_TABLE(i2c, i2c_atmel_id);
200
201#ifdef CONFIG_OF
202static const struct of_device_id i2c_atmel_of_match[] = {
203 {.compatible = "atmel,at97sc3204t"},
204 {},
205};
206MODULE_DEVICE_TABLE(of, i2c_atmel_of_match);
207#endif
208
209static SIMPLE_DEV_PM_OPS(i2c_atmel_pm_ops, tpm_pm_suspend, tpm_pm_resume);
210
211static struct i2c_driver i2c_atmel_driver = {
212 .id_table = i2c_atmel_id,
213 .probe = i2c_atmel_probe,
214 .remove = i2c_atmel_remove,
215 .driver = {
216 .name = I2C_DRIVER_NAME,
217 .pm = &i2c_atmel_pm_ops,
218 .of_match_table = of_match_ptr(i2c_atmel_of_match),
219 },
220};
221
222module_i2c_driver(i2c_atmel_driver);
223
224MODULE_AUTHOR("Jason Gunthorpe <jgunthorpe@obsidianresearch.com>");
225MODULE_DESCRIPTION("Atmel TPM I2C Driver");
226MODULE_LICENSE("GPL");
227