xref: /openbmc/linux/drivers/char/tpm/st33zp24/spi.c (revision be709d48)
1 /*
2  * STMicroelectronics TPM SPI Linux driver for TPM ST33ZP24
3  * Copyright (C) 2009 - 2016 STMicroelectronics
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
17  */
18 
19 #include <linux/module.h>
20 #include <linux/spi/spi.h>
21 #include <linux/gpio.h>
22 #include <linux/gpio/consumer.h>
23 #include <linux/of_irq.h>
24 #include <linux/of_gpio.h>
25 #include <linux/acpi.h>
26 #include <linux/tpm.h>
27 #include <linux/platform_data/st33zp24.h>
28 
29 #include "../tpm.h"
30 #include "st33zp24.h"
31 
32 #define TPM_DATA_FIFO           0x24
33 #define TPM_INTF_CAPABILITY     0x14
34 
35 #define TPM_DUMMY_BYTE		0x00
36 
37 #define MAX_SPI_LATENCY		15
38 #define LOCALITY0		0
39 
40 #define ST33ZP24_OK					0x5A
41 #define ST33ZP24_UNDEFINED_ERR				0x80
42 #define ST33ZP24_BADLOCALITY				0x81
43 #define ST33ZP24_TISREGISTER_UNKNOWN			0x82
44 #define ST33ZP24_LOCALITY_NOT_ACTIVATED			0x83
45 #define ST33ZP24_HASH_END_BEFORE_HASH_START		0x84
46 #define ST33ZP24_BAD_COMMAND_ORDER			0x85
47 #define ST33ZP24_INCORECT_RECEIVED_LENGTH		0x86
48 #define ST33ZP24_TPM_FIFO_OVERFLOW			0x89
49 #define ST33ZP24_UNEXPECTED_READ_FIFO			0x8A
50 #define ST33ZP24_UNEXPECTED_WRITE_FIFO			0x8B
51 #define ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END	0x90
52 #define ST33ZP24_DUMMY_BYTES				0x00
53 
54 /*
55  * TPM command can be up to 2048 byte, A TPM response can be up to
56  * 1024 byte.
57  * Between command and response, there are latency byte (up to 15
58  * usually on st33zp24 2 are enough).
59  *
60  * Overall when sending a command and expecting an answer we need if
61  * worst case:
62  * 2048 (for the TPM command) + 1024 (for the TPM answer).  We need
63  * some latency byte before the answer is available (max 15).
64  * We have 2048 + 1024 + 15.
65  */
66 #define ST33ZP24_SPI_BUFFER_SIZE (ST33ZP24_BUFSIZE + (ST33ZP24_BUFSIZE / 2) +\
67 				  MAX_SPI_LATENCY)
68 
69 
70 struct st33zp24_spi_phy {
71 	struct spi_device *spi_device;
72 
73 	u8 tx_buf[ST33ZP24_SPI_BUFFER_SIZE];
74 	u8 rx_buf[ST33ZP24_SPI_BUFFER_SIZE];
75 
76 	int io_lpcpd;
77 	int latency;
78 };
79 
80 static int st33zp24_status_to_errno(u8 code)
81 {
82 	switch (code) {
83 	case ST33ZP24_OK:
84 		return 0;
85 	case ST33ZP24_UNDEFINED_ERR:
86 	case ST33ZP24_BADLOCALITY:
87 	case ST33ZP24_TISREGISTER_UNKNOWN:
88 	case ST33ZP24_LOCALITY_NOT_ACTIVATED:
89 	case ST33ZP24_HASH_END_BEFORE_HASH_START:
90 	case ST33ZP24_BAD_COMMAND_ORDER:
91 	case ST33ZP24_UNEXPECTED_READ_FIFO:
92 	case ST33ZP24_UNEXPECTED_WRITE_FIFO:
93 	case ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END:
94 		return -EPROTO;
95 	case ST33ZP24_INCORECT_RECEIVED_LENGTH:
96 	case ST33ZP24_TPM_FIFO_OVERFLOW:
97 		return -EMSGSIZE;
98 	case ST33ZP24_DUMMY_BYTES:
99 		return -ENOSYS;
100 	}
101 	return code;
102 }
103 
104 /*
105  * st33zp24_spi_send
106  * Send byte to the TIS register according to the ST33ZP24 SPI protocol.
107  * @param: phy_id, the phy description
108  * @param: tpm_register, the tpm tis register where the data should be written
109  * @param: tpm_data, the tpm_data to write inside the tpm_register
110  * @param: tpm_size, The length of the data
111  * @return: should be zero if success else a negative error code.
112  */
113 static int st33zp24_spi_send(void *phy_id, u8 tpm_register, u8 *tpm_data,
114 			     int tpm_size)
115 {
116 	int total_length = 0, ret = 0;
117 	struct st33zp24_spi_phy *phy = phy_id;
118 	struct spi_device *dev = phy->spi_device;
119 	struct spi_transfer spi_xfer = {
120 		.tx_buf = phy->tx_buf,
121 		.rx_buf = phy->rx_buf,
122 	};
123 
124 	/* Pre-Header */
125 	phy->tx_buf[total_length++] = TPM_WRITE_DIRECTION | LOCALITY0;
126 	phy->tx_buf[total_length++] = tpm_register;
127 
128 	if (tpm_size > 0 && tpm_register == TPM_DATA_FIFO) {
129 		phy->tx_buf[total_length++] = tpm_size >> 8;
130 		phy->tx_buf[total_length++] = tpm_size;
131 	}
132 
133 	memcpy(&phy->tx_buf[total_length], tpm_data, tpm_size);
134 	total_length += tpm_size;
135 
136 	memset(&phy->tx_buf[total_length], TPM_DUMMY_BYTE, phy->latency);
137 
138 	spi_xfer.len = total_length + phy->latency;
139 
140 	ret = spi_sync_transfer(dev, &spi_xfer, 1);
141 	if (ret == 0)
142 		ret = phy->rx_buf[total_length + phy->latency - 1];
143 
144 	return st33zp24_status_to_errno(ret);
145 } /* st33zp24_spi_send() */
146 
147 /*
148  * st33zp24_spi_read8_recv
149  * Recv byte from the TIS register according to the ST33ZP24 SPI protocol.
150  * @param: phy_id, the phy description
151  * @param: tpm_register, the tpm tis register where the data should be read
152  * @param: tpm_data, the TPM response
153  * @param: tpm_size, tpm TPM response size to read.
154  * @return: should be zero if success else a negative error code.
155  */
156 static int st33zp24_spi_read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data,
157 				  int tpm_size)
158 {
159 	int total_length = 0, ret;
160 	struct st33zp24_spi_phy *phy = phy_id;
161 	struct spi_device *dev = phy->spi_device;
162 	struct spi_transfer spi_xfer = {
163 		.tx_buf = phy->tx_buf,
164 		.rx_buf = phy->rx_buf,
165 	};
166 
167 	/* Pre-Header */
168 	phy->tx_buf[total_length++] = LOCALITY0;
169 	phy->tx_buf[total_length++] = tpm_register;
170 
171 	memset(&phy->tx_buf[total_length], TPM_DUMMY_BYTE,
172 	       phy->latency + tpm_size);
173 
174 	spi_xfer.len = total_length + phy->latency + tpm_size;
175 
176 	/* header + status byte + size of the data + status byte */
177 	ret = spi_sync_transfer(dev, &spi_xfer, 1);
178 	if (tpm_size > 0 && ret == 0) {
179 		ret = phy->rx_buf[total_length + phy->latency - 1];
180 
181 		memcpy(tpm_data, phy->rx_buf + total_length + phy->latency,
182 		       tpm_size);
183 	}
184 
185 	return ret;
186 } /* st33zp24_spi_read8_reg() */
187 
188 /*
189  * st33zp24_spi_recv
190  * Recv byte from the TIS register according to the ST33ZP24 SPI protocol.
191  * @param: phy_id, the phy description
192  * @param: tpm_register, the tpm tis register where the data should be read
193  * @param: tpm_data, the TPM response
194  * @param: tpm_size, tpm TPM response size to read.
195  * @return: number of byte read successfully: should be one if success.
196  */
197 static int st33zp24_spi_recv(void *phy_id, u8 tpm_register, u8 *tpm_data,
198 			     int tpm_size)
199 {
200 	int ret;
201 
202 	ret = st33zp24_spi_read8_reg(phy_id, tpm_register, tpm_data, tpm_size);
203 	if (!st33zp24_status_to_errno(ret))
204 		return tpm_size;
205 	return ret;
206 } /* st33zp24_spi_recv() */
207 
208 static int st33zp24_spi_evaluate_latency(void *phy_id)
209 {
210 	struct st33zp24_spi_phy *phy = phy_id;
211 	int latency = 1, status = 0;
212 	u8 data = 0;
213 
214 	while (!status && latency < MAX_SPI_LATENCY) {
215 		phy->latency = latency;
216 		status = st33zp24_spi_read8_reg(phy_id, TPM_INTF_CAPABILITY,
217 						&data, 1);
218 		latency++;
219 	}
220 	if (status < 0)
221 		return status;
222 	if (latency == MAX_SPI_LATENCY)
223 		return -ENODEV;
224 
225 	return latency - 1;
226 } /* evaluate_latency() */
227 
228 static const struct st33zp24_phy_ops spi_phy_ops = {
229 	.send = st33zp24_spi_send,
230 	.recv = st33zp24_spi_recv,
231 };
232 
233 static const struct acpi_gpio_params lpcpd_gpios = { 1, 0, false };
234 
235 static const struct acpi_gpio_mapping acpi_st33zp24_gpios[] = {
236 	{ "lpcpd-gpios", &lpcpd_gpios, 1 },
237 	{},
238 };
239 
240 static int st33zp24_spi_acpi_request_resources(struct spi_device *spi_dev)
241 {
242 	struct tpm_chip *chip = spi_get_drvdata(spi_dev);
243 	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
244 	struct st33zp24_spi_phy *phy = tpm_dev->phy_id;
245 	struct gpio_desc *gpiod_lpcpd;
246 	struct device *dev = &spi_dev->dev;
247 	int ret;
248 
249 	ret = devm_acpi_dev_add_driver_gpios(dev, acpi_st33zp24_gpios);
250 	if (ret)
251 		return ret;
252 
253 	/* Get LPCPD GPIO from ACPI */
254 	gpiod_lpcpd = devm_gpiod_get(dev, "lpcpd", GPIOD_OUT_HIGH);
255 	if (IS_ERR(gpiod_lpcpd)) {
256 		dev_err(dev, "Failed to retrieve lpcpd-gpios from acpi.\n");
257 		phy->io_lpcpd = -1;
258 		/*
259 		 * lpcpd pin is not specified. This is not an issue as
260 		 * power management can be also managed by TPM specific
261 		 * commands. So leave with a success status code.
262 		 */
263 		return 0;
264 	}
265 
266 	phy->io_lpcpd = desc_to_gpio(gpiod_lpcpd);
267 
268 	return 0;
269 }
270 
271 static int st33zp24_spi_of_request_resources(struct spi_device *spi_dev)
272 {
273 	struct tpm_chip *chip = spi_get_drvdata(spi_dev);
274 	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
275 	struct st33zp24_spi_phy *phy = tpm_dev->phy_id;
276 	struct device_node *pp;
277 	int gpio;
278 	int ret;
279 
280 	pp = spi_dev->dev.of_node;
281 	if (!pp) {
282 		dev_err(&spi_dev->dev, "No platform data\n");
283 		return -ENODEV;
284 	}
285 
286 	/* Get GPIO from device tree */
287 	gpio = of_get_named_gpio(pp, "lpcpd-gpios", 0);
288 	if (gpio < 0) {
289 		dev_err(&spi_dev->dev,
290 			"Failed to retrieve lpcpd-gpios from dts.\n");
291 		phy->io_lpcpd = -1;
292 		/*
293 		 * lpcpd pin is not specified. This is not an issue as
294 		 * power management can be also managed by TPM specific
295 		 * commands. So leave with a success status code.
296 		 */
297 		return 0;
298 	}
299 	/* GPIO request and configuration */
300 	ret = devm_gpio_request_one(&spi_dev->dev, gpio,
301 			GPIOF_OUT_INIT_HIGH, "TPM IO LPCPD");
302 	if (ret) {
303 		dev_err(&spi_dev->dev, "Failed to request lpcpd pin\n");
304 		return -ENODEV;
305 	}
306 	phy->io_lpcpd = gpio;
307 
308 	return 0;
309 }
310 
311 static int st33zp24_spi_request_resources(struct spi_device *dev)
312 {
313 	struct tpm_chip *chip = spi_get_drvdata(dev);
314 	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
315 	struct st33zp24_spi_phy *phy = tpm_dev->phy_id;
316 	struct st33zp24_platform_data *pdata;
317 	int ret;
318 
319 	pdata = dev->dev.platform_data;
320 	if (!pdata) {
321 		dev_err(&dev->dev, "No platform data\n");
322 		return -ENODEV;
323 	}
324 
325 	/* store for late use */
326 	phy->io_lpcpd = pdata->io_lpcpd;
327 
328 	if (gpio_is_valid(pdata->io_lpcpd)) {
329 		ret = devm_gpio_request_one(&dev->dev,
330 				pdata->io_lpcpd, GPIOF_OUT_INIT_HIGH,
331 				"TPM IO_LPCPD");
332 		if (ret) {
333 			dev_err(&dev->dev, "%s : reset gpio_request failed\n",
334 				__FILE__);
335 			return ret;
336 		}
337 	}
338 
339 	return 0;
340 }
341 
342 /*
343  * st33zp24_spi_probe initialize the TPM device
344  * @param: dev, the spi_device drescription (TPM SPI description).
345  * @return: 0 in case of success.
346  *	 or a negative value describing the error.
347  */
348 static int st33zp24_spi_probe(struct spi_device *dev)
349 {
350 	int ret;
351 	struct st33zp24_platform_data *pdata;
352 	struct st33zp24_spi_phy *phy;
353 
354 	/* Check SPI platform functionnalities */
355 	if (!dev) {
356 		pr_info("%s: dev is NULL. Device is not accessible.\n",
357 			__func__);
358 		return -ENODEV;
359 	}
360 
361 	phy = devm_kzalloc(&dev->dev, sizeof(struct st33zp24_spi_phy),
362 			   GFP_KERNEL);
363 	if (!phy)
364 		return -ENOMEM;
365 
366 	phy->spi_device = dev;
367 
368 	pdata = dev->dev.platform_data;
369 	if (!pdata && dev->dev.of_node) {
370 		ret = st33zp24_spi_of_request_resources(dev);
371 		if (ret)
372 			return ret;
373 	} else if (pdata) {
374 		ret = st33zp24_spi_request_resources(dev);
375 		if (ret)
376 			return ret;
377 	} else if (ACPI_HANDLE(&dev->dev)) {
378 		ret = st33zp24_spi_acpi_request_resources(dev);
379 		if (ret)
380 			return ret;
381 	}
382 
383 	phy->latency = st33zp24_spi_evaluate_latency(phy);
384 	if (phy->latency <= 0)
385 		return -ENODEV;
386 
387 	return st33zp24_probe(phy, &spi_phy_ops, &dev->dev, dev->irq,
388 			      phy->io_lpcpd);
389 }
390 
391 /*
392  * st33zp24_spi_remove remove the TPM device
393  * @param: client, the spi_device drescription (TPM SPI description).
394  * @return: 0 in case of success.
395  */
396 static int st33zp24_spi_remove(struct spi_device *dev)
397 {
398 	struct tpm_chip *chip = spi_get_drvdata(dev);
399 	int ret;
400 
401 	ret = st33zp24_remove(chip);
402 	if (ret)
403 		return ret;
404 
405 	return 0;
406 }
407 
408 static const struct spi_device_id st33zp24_spi_id[] = {
409 	{TPM_ST33_SPI, 0},
410 	{}
411 };
412 MODULE_DEVICE_TABLE(spi, st33zp24_spi_id);
413 
414 static const struct of_device_id of_st33zp24_spi_match[] = {
415 	{ .compatible = "st,st33zp24-spi", },
416 	{}
417 };
418 MODULE_DEVICE_TABLE(of, of_st33zp24_spi_match);
419 
420 static const struct acpi_device_id st33zp24_spi_acpi_match[] = {
421 	{"SMO3324"},
422 	{}
423 };
424 MODULE_DEVICE_TABLE(acpi, st33zp24_spi_acpi_match);
425 
426 static SIMPLE_DEV_PM_OPS(st33zp24_spi_ops, st33zp24_pm_suspend,
427 			 st33zp24_pm_resume);
428 
429 static struct spi_driver st33zp24_spi_driver = {
430 	.driver = {
431 		.name = TPM_ST33_SPI,
432 		.pm = &st33zp24_spi_ops,
433 		.of_match_table = of_match_ptr(of_st33zp24_spi_match),
434 		.acpi_match_table = ACPI_PTR(st33zp24_spi_acpi_match),
435 	},
436 	.probe = st33zp24_spi_probe,
437 	.remove = st33zp24_spi_remove,
438 	.id_table = st33zp24_spi_id,
439 };
440 
441 module_spi_driver(st33zp24_spi_driver);
442 
443 MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)");
444 MODULE_DESCRIPTION("STM TPM 1.2 SPI ST33 Driver");
445 MODULE_VERSION("1.3.0");
446 MODULE_LICENSE("GPL");
447