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/init.h>
 24#include <linux/module.h>
 25#include <linux/moduleparam.h>
 26#include <linux/slab.h>
 27#include <linux/interrupt.h>
 28#include <linux/wait.h>
 29#include <linux/acpi.h>
 30#include <linux/freezer.h>
 31
 32#include <linux/spi/spi.h>
 33#include <linux/gpio.h>
 34#include <linux/of_irq.h>
 35#include <linux/of_gpio.h>
 36#include <linux/tpm.h>
 37#include "tpm.h"
 38#include "tpm_tis_core.h"
 39
 40#define MAX_SPI_FRAMESIZE 64
 41
 42struct tpm_tis_spi_phy {
 43	struct tpm_tis_data priv;
 44	struct spi_device *spi_device;
 45	u8 *iobuf;
 46};
 47
 48static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *data)
 49{
 50	return container_of(data, struct tpm_tis_spi_phy, priv);
 51}
 52
 53static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
 54				u8 *in, const u8 *out)
 55{
 56	struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
 57	int ret = 0;
 58	int i;
 59	struct spi_message m;
 60	struct spi_transfer spi_xfer;
 61	u8 transfer_len;
 62
 63	spi_bus_lock(phy->spi_device->master);
 64
 65	while (len) {
 66		transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
 67
 68		phy->iobuf[0] = (in ? 0x80 : 0) | (transfer_len - 1);
 69		phy->iobuf[1] = 0xd4;
 70		phy->iobuf[2] = addr >> 8;
 71		phy->iobuf[3] = addr;
 72
 73		memset(&spi_xfer, 0, sizeof(spi_xfer));
 74		spi_xfer.tx_buf = phy->iobuf;
 75		spi_xfer.rx_buf = phy->iobuf;
 76		spi_xfer.len = 4;
 77		spi_xfer.cs_change = 1;
 78
 79		spi_message_init(&m);
 80		spi_message_add_tail(&spi_xfer, &m);
 81		ret = spi_sync_locked(phy->spi_device, &m);
 82		if (ret < 0)
 83			goto exit;
 84
 85		if ((phy->iobuf[3] & 0x01) == 0) {
 86			// handle SPI wait states
 87			phy->iobuf[0] = 0;
 88
 89			for (i = 0; i < TPM_RETRY; i++) {
 90				spi_xfer.len = 1;
 91				spi_message_init(&m);
 92				spi_message_add_tail(&spi_xfer, &m);
 93				ret = spi_sync_locked(phy->spi_device, &m);
 94				if (ret < 0)
 95					goto exit;
 96				if (phy->iobuf[0] & 0x01)
 97					break;
 98			}
 99
100			if (i == TPM_RETRY) {
101				ret = -ETIMEDOUT;
102				goto exit;
103			}
104		}
105
106		spi_xfer.cs_change = 0;
107		spi_xfer.len = transfer_len;
108		spi_xfer.delay_usecs = 5;
109
110		if (in) {
111			spi_xfer.tx_buf = NULL;
112		} else if (out) {
113			spi_xfer.rx_buf = NULL;
114			memcpy(phy->iobuf, out, transfer_len);
115			out += transfer_len;
116		}
117
118		spi_message_init(&m);
119		spi_message_add_tail(&spi_xfer, &m);
120		ret = spi_sync_locked(phy->spi_device, &m);
121		if (ret < 0)
122			goto exit;
123
124		if (in) {
125			memcpy(in, phy->iobuf, transfer_len);
126			in += transfer_len;
127		}
128
129		len -= transfer_len;
130	}
131
132exit:
133	spi_bus_unlock(phy->spi_device->master);
134	return ret;
135}
136
137static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,
138				  u16 len, u8 *result)
139{
140	return tpm_tis_spi_transfer(data, addr, len, result, NULL);
141}
142
143static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,
144				   u16 len, const u8 *value)
145{
146	return tpm_tis_spi_transfer(data, addr, len, NULL, value);
147}
148
149static int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result)
150{
151	__le16 result_le;
152	int rc;
153
154	rc = data->phy_ops->read_bytes(data, addr, sizeof(u16),
155				       (u8 *)&result_le);
156	if (!rc)
157		*result = le16_to_cpu(result_le);
158
159	return rc;
160}
161
162static int tpm_tis_spi_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
163{
164	__le32 result_le;
165	int rc;
166
167	rc = data->phy_ops->read_bytes(data, addr, sizeof(u32),
168				       (u8 *)&result_le);
169	if (!rc)
170		*result = le32_to_cpu(result_le);
171
172	return rc;
173}
174
175static int tpm_tis_spi_write32(struct tpm_tis_data *data, u32 addr, u32 value)
176{
177	__le32 value_le;
178	int rc;
179
180	value_le = cpu_to_le32(value);
181	rc = data->phy_ops->write_bytes(data, addr, sizeof(u32),
182					(u8 *)&value_le);
183
184	return rc;
185}
186
187static const struct tpm_tis_phy_ops tpm_spi_phy_ops = {
188	.read_bytes = tpm_tis_spi_read_bytes,
189	.write_bytes = tpm_tis_spi_write_bytes,
190	.read16 = tpm_tis_spi_read16,
191	.read32 = tpm_tis_spi_read32,
192	.write32 = tpm_tis_spi_write32,
193};
194
195static int tpm_tis_spi_probe(struct spi_device *dev)
196{
197	struct tpm_tis_spi_phy *phy;
198	int irq;
199
200	phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_spi_phy),
201			   GFP_KERNEL);
202	if (!phy)
203		return -ENOMEM;
204
205	phy->spi_device = dev;
206
207	phy->iobuf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL);
208	if (!phy->iobuf)
209		return -ENOMEM;
210
211	/* If the SPI device has an IRQ then use that */
212	if (dev->irq > 0)
213		irq = dev->irq;
214	else
215		irq = -1;
216
217	return tpm_tis_core_init(&dev->dev, &phy->priv, irq, &tpm_spi_phy_ops,
218				 NULL);
219}
220
221static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume);
222
223static int tpm_tis_spi_remove(struct spi_device *dev)
224{
225	struct tpm_chip *chip = spi_get_drvdata(dev);
226
227	tpm_chip_unregister(chip);
228	tpm_tis_remove(chip);
229	return 0;
230}
231
232static const struct spi_device_id tpm_tis_spi_id[] = {
233	{"tpm_tis_spi", 0},
234	{}
235};
236MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);
237
238static const struct of_device_id of_tis_spi_match[] = {
239	{ .compatible = "st,st33htpm-spi", },
240	{ .compatible = "infineon,slb9670", },
241	{ .compatible = "tcg,tpm_tis-spi", },
242	{}
243};
244MODULE_DEVICE_TABLE(of, of_tis_spi_match);
245
246static const struct acpi_device_id acpi_tis_spi_match[] = {
247	{"SMO0768", 0},
248	{}
249};
250MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match);
251
252static struct spi_driver tpm_tis_spi_driver = {
253	.driver = {
254		.owner = THIS_MODULE,
255		.name = "tpm_tis_spi",
256		.pm = &tpm_tis_pm,
257		.of_match_table = of_match_ptr(of_tis_spi_match),
258		.acpi_match_table = ACPI_PTR(acpi_tis_spi_match),
259	},
260	.probe = tpm_tis_spi_probe,
261	.remove = tpm_tis_spi_remove,
262	.id_table = tpm_tis_spi_id,
263};
264module_spi_driver(tpm_tis_spi_driver);
265
266MODULE_DESCRIPTION("TPM Driver for native SPI access");
267MODULE_LICENSE("GPL");