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