1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2015 Infineon Technologies AG
4 * Copyright (C) 2016 STMicroelectronics SAS
5 *
6 * Authors:
7 * Peter Huewe <peter.huewe@infineon.com>
8 * Christophe Ricard <christophe-h.ricard@st.com>
9 *
10 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
11 *
12 * Device driver for TCG/TCPA TPM (trusted platform module).
13 * Specifications at www.trustedcomputinggroup.org
14 *
15 * This device driver implements the TPM interface as defined in
16 * the TCG TPM Interface Spec version 1.3, revision 27 via _raw/native
17 * SPI access_.
18 *
19 * It is based on the original tpm_tis device driver from Leendert van
20 * Dorn and Kyleen Hall and Jarko Sakkinnen.
21 */
22
23 #include <linux/acpi.h>
24 #include <linux/completion.h>
25 #include <linux/init.h>
26 #include <linux/interrupt.h>
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/slab.h>
30
31 #include <linux/of.h>
32 #include <linux/spi/spi.h>
33 #include <linux/tpm.h>
34
35 #include "tpm.h"
36 #include "tpm_tis_core.h"
37 #include "tpm_tis_spi.h"
38
39 #define MAX_SPI_FRAMESIZE 64
40 #define SPI_HDRSIZE 4
41
42 /*
43 * TCG SPI flow control is documented in section 6.4 of the spec[1]. In short,
44 * keep trying to read from the device until MISO goes high indicating the
45 * wait state has ended.
46 *
47 * [1] https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
48 */
tpm_tis_spi_flow_control(struct tpm_tis_spi_phy * phy,struct spi_transfer * spi_xfer)49 static int tpm_tis_spi_flow_control(struct tpm_tis_spi_phy *phy,
50 struct spi_transfer *spi_xfer)
51 {
52 struct spi_message m;
53 int ret, i;
54
55 if ((phy->iobuf[3] & 0x01) == 0) {
56 // handle SPI wait states
57 for (i = 0; i < TPM_RETRY; i++) {
58 spi_xfer->len = 1;
59 spi_message_init(&m);
60 spi_message_add_tail(spi_xfer, &m);
61 ret = spi_sync_locked(phy->spi_device, &m);
62 if (ret < 0)
63 return ret;
64 if (phy->iobuf[0] & 0x01)
65 break;
66 }
67
68 if (i == TPM_RETRY)
69 return -ETIMEDOUT;
70 }
71
72 return 0;
73 }
74
75 /*
76 * Half duplex controller with support for TPM wait state detection like
77 * Tegra QSPI need CMD, ADDR & DATA sent in single message to manage HW flow
78 * control. Each phase sent in different transfer for controller to idenity
79 * phase.
80 */
tpm_tis_spi_transfer_half(struct tpm_tis_data * data,u32 addr,u16 len,u8 * in,const u8 * out)81 static int tpm_tis_spi_transfer_half(struct tpm_tis_data *data, u32 addr,
82 u16 len, u8 *in, const u8 *out)
83 {
84 struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
85 struct spi_transfer spi_xfer[3];
86 struct spi_message m;
87 u8 transfer_len;
88 int ret;
89
90 while (len) {
91 transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
92
93 spi_message_init(&m);
94 phy->iobuf[0] = (in ? 0x80 : 0) | (transfer_len - 1);
95 phy->iobuf[1] = 0xd4;
96 phy->iobuf[2] = addr >> 8;
97 phy->iobuf[3] = addr;
98
99 memset(&spi_xfer, 0, sizeof(spi_xfer));
100
101 spi_xfer[0].tx_buf = phy->iobuf;
102 spi_xfer[0].len = 1;
103 spi_message_add_tail(&spi_xfer[0], &m);
104
105 spi_xfer[1].tx_buf = phy->iobuf + 1;
106 spi_xfer[1].len = 3;
107 spi_message_add_tail(&spi_xfer[1], &m);
108
109 if (out) {
110 spi_xfer[2].tx_buf = &phy->iobuf[4];
111 spi_xfer[2].rx_buf = NULL;
112 memcpy(&phy->iobuf[4], out, transfer_len);
113 out += transfer_len;
114 }
115
116 if (in) {
117 spi_xfer[2].tx_buf = NULL;
118 spi_xfer[2].rx_buf = &phy->iobuf[4];
119 }
120
121 spi_xfer[2].len = transfer_len;
122 spi_message_add_tail(&spi_xfer[2], &m);
123
124 reinit_completion(&phy->ready);
125
126 ret = spi_sync(phy->spi_device, &m);
127 if (ret < 0)
128 return ret;
129
130 if (in) {
131 memcpy(in, &phy->iobuf[4], transfer_len);
132 in += transfer_len;
133 }
134
135 len -= transfer_len;
136 }
137
138 return ret;
139 }
140
tpm_tis_spi_transfer_full(struct tpm_tis_data * data,u32 addr,u16 len,u8 * in,const u8 * out)141 static int tpm_tis_spi_transfer_full(struct tpm_tis_data *data, u32 addr,
142 u16 len, u8 *in, const u8 *out)
143 {
144 struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
145 int ret = 0;
146 struct spi_message m;
147 struct spi_transfer spi_xfer;
148 u8 transfer_len;
149
150 spi_bus_lock(phy->spi_device->master);
151
152 while (len) {
153 transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
154
155 phy->iobuf[0] = (in ? 0x80 : 0) | (transfer_len - 1);
156 phy->iobuf[1] = 0xd4;
157 phy->iobuf[2] = addr >> 8;
158 phy->iobuf[3] = addr;
159
160 memset(&spi_xfer, 0, sizeof(spi_xfer));
161 spi_xfer.tx_buf = phy->iobuf;
162 spi_xfer.rx_buf = phy->iobuf;
163 spi_xfer.len = 4;
164 spi_xfer.cs_change = 1;
165
166 spi_message_init(&m);
167 spi_message_add_tail(&spi_xfer, &m);
168 ret = spi_sync_locked(phy->spi_device, &m);
169 if (ret < 0)
170 goto exit;
171
172 /* Flow control transfers are receive only */
173 spi_xfer.tx_buf = NULL;
174 ret = phy->flow_control(phy, &spi_xfer);
175 if (ret < 0)
176 goto exit;
177
178 spi_xfer.cs_change = 0;
179 spi_xfer.len = transfer_len;
180 spi_xfer.delay.value = 5;
181 spi_xfer.delay.unit = SPI_DELAY_UNIT_USECS;
182
183 if (out) {
184 spi_xfer.tx_buf = phy->iobuf;
185 spi_xfer.rx_buf = NULL;
186 memcpy(phy->iobuf, out, transfer_len);
187 out += transfer_len;
188 }
189
190 spi_message_init(&m);
191 spi_message_add_tail(&spi_xfer, &m);
192 reinit_completion(&phy->ready);
193 ret = spi_sync_locked(phy->spi_device, &m);
194 if (ret < 0)
195 goto exit;
196
197 if (in) {
198 memcpy(in, phy->iobuf, transfer_len);
199 in += transfer_len;
200 }
201
202 len -= transfer_len;
203 }
204
205 exit:
206 if (ret < 0) {
207 /* Deactivate chip select */
208 memset(&spi_xfer, 0, sizeof(spi_xfer));
209 spi_message_init(&m);
210 spi_message_add_tail(&spi_xfer, &m);
211 spi_sync_locked(phy->spi_device, &m);
212 }
213
214 spi_bus_unlock(phy->spi_device->master);
215 return ret;
216 }
217
tpm_tis_spi_transfer(struct tpm_tis_data * data,u32 addr,u16 len,u8 * in,const u8 * out)218 int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
219 u8 *in, const u8 *out)
220 {
221 struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
222 struct spi_controller *ctlr = phy->spi_device->controller;
223
224 /*
225 * TPM flow control over SPI requires full duplex support.
226 * Send entire message to a half duplex controller to handle
227 * wait polling in controller.
228 * Set TPM HW flow control flag..
229 */
230 if (ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX)
231 return tpm_tis_spi_transfer_half(data, addr, len, in, out);
232 else
233 return tpm_tis_spi_transfer_full(data, addr, len, in, out);
234 }
235
tpm_tis_spi_read_bytes(struct tpm_tis_data * data,u32 addr,u16 len,u8 * result,enum tpm_tis_io_mode io_mode)236 static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,
237 u16 len, u8 *result, enum tpm_tis_io_mode io_mode)
238 {
239 return tpm_tis_spi_transfer(data, addr, len, result, NULL);
240 }
241
tpm_tis_spi_write_bytes(struct tpm_tis_data * data,u32 addr,u16 len,const u8 * value,enum tpm_tis_io_mode io_mode)242 static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,
243 u16 len, const u8 *value, enum tpm_tis_io_mode io_mode)
244 {
245 return tpm_tis_spi_transfer(data, addr, len, NULL, value);
246 }
247
tpm_tis_spi_init(struct spi_device * spi,struct tpm_tis_spi_phy * phy,int irq,const struct tpm_tis_phy_ops * phy_ops)248 int tpm_tis_spi_init(struct spi_device *spi, struct tpm_tis_spi_phy *phy,
249 int irq, const struct tpm_tis_phy_ops *phy_ops)
250 {
251 phy->iobuf = devm_kmalloc(&spi->dev, SPI_HDRSIZE + MAX_SPI_FRAMESIZE, GFP_KERNEL);
252 if (!phy->iobuf)
253 return -ENOMEM;
254
255 phy->spi_device = spi;
256
257 return tpm_tis_core_init(&spi->dev, &phy->priv, irq, phy_ops, NULL);
258 }
259
260 static const struct tpm_tis_phy_ops tpm_spi_phy_ops = {
261 .read_bytes = tpm_tis_spi_read_bytes,
262 .write_bytes = tpm_tis_spi_write_bytes,
263 };
264
tpm_tis_spi_probe(struct spi_device * dev)265 static int tpm_tis_spi_probe(struct spi_device *dev)
266 {
267 struct tpm_tis_spi_phy *phy;
268 int irq;
269
270 phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_spi_phy),
271 GFP_KERNEL);
272 if (!phy)
273 return -ENOMEM;
274
275 phy->flow_control = tpm_tis_spi_flow_control;
276
277 if (dev->controller->flags & SPI_CONTROLLER_HALF_DUPLEX)
278 dev->mode |= SPI_TPM_HW_FLOW;
279
280 /* If the SPI device has an IRQ then use that */
281 if (dev->irq > 0)
282 irq = dev->irq;
283 else
284 irq = -1;
285
286 init_completion(&phy->ready);
287 return tpm_tis_spi_init(dev, phy, irq, &tpm_spi_phy_ops);
288 }
289
290 typedef int (*tpm_tis_spi_probe_func)(struct spi_device *);
291
tpm_tis_spi_driver_probe(struct spi_device * spi)292 static int tpm_tis_spi_driver_probe(struct spi_device *spi)
293 {
294 const struct spi_device_id *spi_dev_id = spi_get_device_id(spi);
295 tpm_tis_spi_probe_func probe_func;
296
297 probe_func = of_device_get_match_data(&spi->dev);
298 if (!probe_func) {
299 if (spi_dev_id) {
300 probe_func = (tpm_tis_spi_probe_func)spi_dev_id->driver_data;
301 if (!probe_func)
302 return -ENODEV;
303 } else
304 probe_func = tpm_tis_spi_probe;
305 }
306
307 return probe_func(spi);
308 }
309
310 static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_spi_resume);
311
tpm_tis_spi_remove(struct spi_device * dev)312 static void tpm_tis_spi_remove(struct spi_device *dev)
313 {
314 struct tpm_chip *chip = spi_get_drvdata(dev);
315
316 tpm_chip_unregister(chip);
317 tpm_tis_remove(chip);
318 }
319
320 static const struct spi_device_id tpm_tis_spi_id[] = {
321 { "st33htpm-spi", (unsigned long)tpm_tis_spi_probe },
322 { "slb9670", (unsigned long)tpm_tis_spi_probe },
323 { "tpm_tis_spi", (unsigned long)tpm_tis_spi_probe },
324 { "tpm_tis-spi", (unsigned long)tpm_tis_spi_probe },
325 { "cr50", (unsigned long)cr50_spi_probe },
326 {}
327 };
328 MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);
329
330 static const struct of_device_id of_tis_spi_match[] __maybe_unused = {
331 { .compatible = "st,st33htpm-spi", .data = tpm_tis_spi_probe },
332 { .compatible = "infineon,slb9670", .data = tpm_tis_spi_probe },
333 { .compatible = "tcg,tpm_tis-spi", .data = tpm_tis_spi_probe },
334 { .compatible = "google,cr50", .data = cr50_spi_probe },
335 {}
336 };
337 MODULE_DEVICE_TABLE(of, of_tis_spi_match);
338
339 static const struct acpi_device_id acpi_tis_spi_match[] __maybe_unused = {
340 {"SMO0768", 0},
341 {}
342 };
343 MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match);
344
345 static struct spi_driver tpm_tis_spi_driver = {
346 .driver = {
347 .name = "tpm_tis_spi",
348 .pm = &tpm_tis_pm,
349 .of_match_table = of_match_ptr(of_tis_spi_match),
350 .acpi_match_table = ACPI_PTR(acpi_tis_spi_match),
351 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
352 },
353 .probe = tpm_tis_spi_driver_probe,
354 .remove = tpm_tis_spi_remove,
355 .id_table = tpm_tis_spi_id,
356 };
357 module_spi_driver(tpm_tis_spi_driver);
358
359 MODULE_DESCRIPTION("TPM Driver for native SPI access");
360 MODULE_LICENSE("GPL");
361