1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * STMicroelectronics TPM SPI Linux driver for TPM ST33ZP24
4 * Copyright (C) 2009 - 2016 STMicroelectronics
5 */
6
7 #include <linux/module.h>
8 #include <linux/spi/spi.h>
9 #include <linux/of.h>
10 #include <linux/acpi.h>
11 #include <linux/tpm.h>
12
13 #include "../tpm.h"
14 #include "st33zp24.h"
15
16 #define TPM_DATA_FIFO 0x24
17 #define TPM_INTF_CAPABILITY 0x14
18
19 #define TPM_DUMMY_BYTE 0x00
20
21 #define MAX_SPI_LATENCY 15
22 #define LOCALITY0 0
23
24 #define ST33ZP24_OK 0x5A
25 #define ST33ZP24_UNDEFINED_ERR 0x80
26 #define ST33ZP24_BADLOCALITY 0x81
27 #define ST33ZP24_TISREGISTER_UNKNOWN 0x82
28 #define ST33ZP24_LOCALITY_NOT_ACTIVATED 0x83
29 #define ST33ZP24_HASH_END_BEFORE_HASH_START 0x84
30 #define ST33ZP24_BAD_COMMAND_ORDER 0x85
31 #define ST33ZP24_INCORECT_RECEIVED_LENGTH 0x86
32 #define ST33ZP24_TPM_FIFO_OVERFLOW 0x89
33 #define ST33ZP24_UNEXPECTED_READ_FIFO 0x8A
34 #define ST33ZP24_UNEXPECTED_WRITE_FIFO 0x8B
35 #define ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END 0x90
36 #define ST33ZP24_DUMMY_BYTES 0x00
37
38 /*
39 * TPM command can be up to 2048 byte, A TPM response can be up to
40 * 1024 byte.
41 * Between command and response, there are latency byte (up to 15
42 * usually on st33zp24 2 are enough).
43 *
44 * Overall when sending a command and expecting an answer we need if
45 * worst case:
46 * 2048 (for the TPM command) + 1024 (for the TPM answer). We need
47 * some latency byte before the answer is available (max 15).
48 * We have 2048 + 1024 + 15.
49 */
50 #define ST33ZP24_SPI_BUFFER_SIZE (ST33ZP24_BUFSIZE + (ST33ZP24_BUFSIZE / 2) +\
51 MAX_SPI_LATENCY)
52
53
54 struct st33zp24_spi_phy {
55 struct spi_device *spi_device;
56
57 u8 tx_buf[ST33ZP24_SPI_BUFFER_SIZE];
58 u8 rx_buf[ST33ZP24_SPI_BUFFER_SIZE];
59
60 int latency;
61 };
62
st33zp24_status_to_errno(u8 code)63 static int st33zp24_status_to_errno(u8 code)
64 {
65 switch (code) {
66 case ST33ZP24_OK:
67 return 0;
68 case ST33ZP24_UNDEFINED_ERR:
69 case ST33ZP24_BADLOCALITY:
70 case ST33ZP24_TISREGISTER_UNKNOWN:
71 case ST33ZP24_LOCALITY_NOT_ACTIVATED:
72 case ST33ZP24_HASH_END_BEFORE_HASH_START:
73 case ST33ZP24_BAD_COMMAND_ORDER:
74 case ST33ZP24_UNEXPECTED_READ_FIFO:
75 case ST33ZP24_UNEXPECTED_WRITE_FIFO:
76 case ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END:
77 return -EPROTO;
78 case ST33ZP24_INCORECT_RECEIVED_LENGTH:
79 case ST33ZP24_TPM_FIFO_OVERFLOW:
80 return -EMSGSIZE;
81 case ST33ZP24_DUMMY_BYTES:
82 return -ENOSYS;
83 }
84 return code;
85 }
86
87 /*
88 * st33zp24_spi_send
89 * Send byte to the TIS register according to the ST33ZP24 SPI protocol.
90 * @param: phy_id, the phy description
91 * @param: tpm_register, the tpm tis register where the data should be written
92 * @param: tpm_data, the tpm_data to write inside the tpm_register
93 * @param: tpm_size, The length of the data
94 * @return: should be zero if success else a negative error code.
95 */
st33zp24_spi_send(void * phy_id,u8 tpm_register,u8 * tpm_data,int tpm_size)96 static int st33zp24_spi_send(void *phy_id, u8 tpm_register, u8 *tpm_data,
97 int tpm_size)
98 {
99 int total_length = 0, ret = 0;
100 struct st33zp24_spi_phy *phy = phy_id;
101 struct spi_device *dev = phy->spi_device;
102 struct spi_transfer spi_xfer = {
103 .tx_buf = phy->tx_buf,
104 .rx_buf = phy->rx_buf,
105 };
106
107 /* Pre-Header */
108 phy->tx_buf[total_length++] = TPM_WRITE_DIRECTION | LOCALITY0;
109 phy->tx_buf[total_length++] = tpm_register;
110
111 if (tpm_size > 0 && tpm_register == TPM_DATA_FIFO) {
112 phy->tx_buf[total_length++] = tpm_size >> 8;
113 phy->tx_buf[total_length++] = tpm_size;
114 }
115
116 memcpy(&phy->tx_buf[total_length], tpm_data, tpm_size);
117 total_length += tpm_size;
118
119 memset(&phy->tx_buf[total_length], TPM_DUMMY_BYTE, phy->latency);
120
121 spi_xfer.len = total_length + phy->latency;
122
123 ret = spi_sync_transfer(dev, &spi_xfer, 1);
124 if (ret == 0)
125 ret = phy->rx_buf[total_length + phy->latency - 1];
126
127 return st33zp24_status_to_errno(ret);
128 } /* st33zp24_spi_send() */
129
130 /*
131 * st33zp24_spi_read8_recv
132 * Recv byte from the TIS register according to the ST33ZP24 SPI protocol.
133 * @param: phy_id, the phy description
134 * @param: tpm_register, the tpm tis register where the data should be read
135 * @param: tpm_data, the TPM response
136 * @param: tpm_size, tpm TPM response size to read.
137 * @return: should be zero if success else a negative error code.
138 */
st33zp24_spi_read8_reg(void * phy_id,u8 tpm_register,u8 * tpm_data,int tpm_size)139 static int st33zp24_spi_read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data,
140 int tpm_size)
141 {
142 int total_length = 0, ret;
143 struct st33zp24_spi_phy *phy = phy_id;
144 struct spi_device *dev = phy->spi_device;
145 struct spi_transfer spi_xfer = {
146 .tx_buf = phy->tx_buf,
147 .rx_buf = phy->rx_buf,
148 };
149
150 /* Pre-Header */
151 phy->tx_buf[total_length++] = LOCALITY0;
152 phy->tx_buf[total_length++] = tpm_register;
153
154 memset(&phy->tx_buf[total_length], TPM_DUMMY_BYTE,
155 phy->latency + tpm_size);
156
157 spi_xfer.len = total_length + phy->latency + tpm_size;
158
159 /* header + status byte + size of the data + status byte */
160 ret = spi_sync_transfer(dev, &spi_xfer, 1);
161 if (tpm_size > 0 && ret == 0) {
162 ret = phy->rx_buf[total_length + phy->latency - 1];
163
164 memcpy(tpm_data, phy->rx_buf + total_length + phy->latency,
165 tpm_size);
166 }
167
168 return ret;
169 } /* st33zp24_spi_read8_reg() */
170
171 /*
172 * st33zp24_spi_recv
173 * Recv byte from the TIS register according to the ST33ZP24 SPI protocol.
174 * @param: phy_id, the phy description
175 * @param: tpm_register, the tpm tis register where the data should be read
176 * @param: tpm_data, the TPM response
177 * @param: tpm_size, tpm TPM response size to read.
178 * @return: number of byte read successfully: should be one if success.
179 */
st33zp24_spi_recv(void * phy_id,u8 tpm_register,u8 * tpm_data,int tpm_size)180 static int st33zp24_spi_recv(void *phy_id, u8 tpm_register, u8 *tpm_data,
181 int tpm_size)
182 {
183 int ret;
184
185 ret = st33zp24_spi_read8_reg(phy_id, tpm_register, tpm_data, tpm_size);
186 if (!st33zp24_status_to_errno(ret))
187 return tpm_size;
188 return ret;
189 } /* st33zp24_spi_recv() */
190
st33zp24_spi_evaluate_latency(void * phy_id)191 static int st33zp24_spi_evaluate_latency(void *phy_id)
192 {
193 struct st33zp24_spi_phy *phy = phy_id;
194 int latency = 1, status = 0;
195 u8 data = 0;
196
197 while (!status && latency < MAX_SPI_LATENCY) {
198 phy->latency = latency;
199 status = st33zp24_spi_read8_reg(phy_id, TPM_INTF_CAPABILITY,
200 &data, 1);
201 latency++;
202 }
203 if (status < 0)
204 return status;
205 if (latency == MAX_SPI_LATENCY)
206 return -ENODEV;
207
208 return latency - 1;
209 } /* evaluate_latency() */
210
211 static const struct st33zp24_phy_ops spi_phy_ops = {
212 .send = st33zp24_spi_send,
213 .recv = st33zp24_spi_recv,
214 };
215
216 /*
217 * st33zp24_spi_probe initialize the TPM device
218 * @param: dev, the spi_device description (TPM SPI description).
219 * @return: 0 in case of success.
220 * or a negative value describing the error.
221 */
st33zp24_spi_probe(struct spi_device * dev)222 static int st33zp24_spi_probe(struct spi_device *dev)
223 {
224 struct st33zp24_spi_phy *phy;
225
226 phy = devm_kzalloc(&dev->dev, sizeof(struct st33zp24_spi_phy),
227 GFP_KERNEL);
228 if (!phy)
229 return -ENOMEM;
230
231 phy->spi_device = dev;
232
233 phy->latency = st33zp24_spi_evaluate_latency(phy);
234 if (phy->latency <= 0)
235 return -ENODEV;
236
237 return st33zp24_probe(phy, &spi_phy_ops, &dev->dev, dev->irq);
238 }
239
240 /*
241 * st33zp24_spi_remove remove the TPM device
242 * @param: client, the spi_device description (TPM SPI description).
243 * @return: 0 in case of success.
244 */
st33zp24_spi_remove(struct spi_device * dev)245 static void st33zp24_spi_remove(struct spi_device *dev)
246 {
247 struct tpm_chip *chip = spi_get_drvdata(dev);
248
249 st33zp24_remove(chip);
250 }
251
252 static const struct spi_device_id st33zp24_spi_id[] = {
253 {TPM_ST33_SPI, 0},
254 {}
255 };
256 MODULE_DEVICE_TABLE(spi, st33zp24_spi_id);
257
258 static const struct of_device_id of_st33zp24_spi_match[] __maybe_unused = {
259 { .compatible = "st,st33zp24-spi", },
260 {}
261 };
262 MODULE_DEVICE_TABLE(of, of_st33zp24_spi_match);
263
264 static const struct acpi_device_id st33zp24_spi_acpi_match[] __maybe_unused = {
265 {"SMO3324"},
266 {}
267 };
268 MODULE_DEVICE_TABLE(acpi, st33zp24_spi_acpi_match);
269
270 static SIMPLE_DEV_PM_OPS(st33zp24_spi_ops, st33zp24_pm_suspend,
271 st33zp24_pm_resume);
272
273 static struct spi_driver st33zp24_spi_driver = {
274 .driver = {
275 .name = "st33zp24-spi",
276 .pm = &st33zp24_spi_ops,
277 .of_match_table = of_match_ptr(of_st33zp24_spi_match),
278 .acpi_match_table = ACPI_PTR(st33zp24_spi_acpi_match),
279 },
280 .probe = st33zp24_spi_probe,
281 .remove = st33zp24_spi_remove,
282 .id_table = st33zp24_spi_id,
283 };
284
285 module_spi_driver(st33zp24_spi_driver);
286
287 MODULE_AUTHOR("TPM support <TPMsupport@list.st.com>");
288 MODULE_DESCRIPTION("STM TPM 1.2 SPI ST33 Driver");
289 MODULE_VERSION("1.3.0");
290 MODULE_LICENSE("GPL");
291