1/*
  2 * Copyright (C) 2015 Infineon Technologies AG
  3 * Copyright (C) 2016 STMicroelectronics SAS
  4 *
  5 * Authors:
  6 * Peter Huewe <peter.huewe@infineon.com>
  7 * Christophe Ricard <christophe-h.ricard@st.com>
  8 *
  9 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
 10 *
 11 * Device driver for TCG/TCPA TPM (trusted platform module).
 12 * Specifications at www.trustedcomputinggroup.org
 13 *
 14 * This device driver implements the TPM interface as defined in
 15 * the TCG TPM Interface Spec version 1.3, revision 27 via _raw/native
 16 * SPI access_.
 17 *
 18 * It is based on the original tpm_tis device driver from Leendert van
 19 * Dorn and Kyleen Hall and Jarko Sakkinnen.
 20 *
 21 * This program is free software; you can redistribute it and/or
 22 * modify it under the terms of the GNU General Public License as
 23 * published by the Free Software Foundation, version 2 of the
 24 * License.
 25 */
 26
 27#include <linux/init.h>
 28#include <linux/module.h>
 29#include <linux/moduleparam.h>
 30#include <linux/slab.h>
 31#include <linux/interrupt.h>
 32#include <linux/wait.h>
 33#include <linux/acpi.h>
 34#include <linux/freezer.h>
 35
 36#include <linux/spi/spi.h>
 37#include <linux/gpio.h>
 38#include <linux/of_irq.h>
 39#include <linux/of_gpio.h>
 40#include <linux/tpm.h>
 41#include "tpm.h"
 42#include "tpm_tis_core.h"
 43
 44#define MAX_SPI_FRAMESIZE 64
 45
 46struct tpm_tis_spi_phy {
 47	struct tpm_tis_data priv;
 48	struct spi_device *spi_device;
 49	u8 *iobuf;
 50};
 51
 52static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *data)
 53{
 54	return container_of(data, struct tpm_tis_spi_phy, priv);
 55}
 56
 57static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
 58				u8 *in, const u8 *out)
 59{
 60	struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
 61	int ret = 0;
 62	int i;
 63	struct spi_message m;
 64	struct spi_transfer spi_xfer;
 65	u8 transfer_len;
 66
 67	spi_bus_lock(phy->spi_device->master);
 68
 69	while (len) {
 70		transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
 71
 72		phy->iobuf[0] = (in ? 0x80 : 0) | (transfer_len - 1);
 73		phy->iobuf[1] = 0xd4;
 74		phy->iobuf[2] = addr >> 8;
 75		phy->iobuf[3] = addr;
 76
 77		memset(&spi_xfer, 0, sizeof(spi_xfer));
 78		spi_xfer.tx_buf = phy->iobuf;
 79		spi_xfer.rx_buf = phy->iobuf;
 80		spi_xfer.len = 4;
 81		spi_xfer.cs_change = 1;
 82
 83		spi_message_init(&m);
 84		spi_message_add_tail(&spi_xfer, &m);
 85		ret = spi_sync_locked(phy->spi_device, &m);
 86		if (ret < 0)
 87			goto exit;
 88
 89		if ((phy->iobuf[3] & 0x01) == 0) {
 90			// handle SPI wait states
 91			phy->iobuf[0] = 0;
 92
 93			for (i = 0; i < TPM_RETRY; i++) {
 94				spi_xfer.len = 1;
 95				spi_message_init(&m);
 96				spi_message_add_tail(&spi_xfer, &m);
 97				ret = spi_sync_locked(phy->spi_device, &m);
 98				if (ret < 0)
 99					goto exit;
100				if (phy->iobuf[0] & 0x01)
101					break;
102			}
103
104			if (i == TPM_RETRY) {
105				ret = -ETIMEDOUT;
106				goto exit;
107			}
108		}
109
110		spi_xfer.cs_change = 0;
111		spi_xfer.len = transfer_len;
112		spi_xfer.delay_usecs = 5;
113
114		if (in) {
115			spi_xfer.tx_buf = NULL;
116		} else if (out) {
117			spi_xfer.rx_buf = NULL;
118			memcpy(phy->iobuf, out, transfer_len);
119			out += transfer_len;
120		}
121
122		spi_message_init(&m);
123		spi_message_add_tail(&spi_xfer, &m);
124		ret = spi_sync_locked(phy->spi_device, &m);
125		if (ret < 0)
126			goto exit;
127
128		if (in) {
129			memcpy(in, phy->iobuf, transfer_len);
130			in += transfer_len;
131		}
132
133		len -= transfer_len;
134	}
135
136exit:
137	spi_bus_unlock(phy->spi_device->master);
138	return ret;
139}
140
141static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,
142				  u16 len, u8 *result)
143{
144	return tpm_tis_spi_transfer(data, addr, len, result, NULL);
145}
146
147static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,
148				   u16 len, const u8 *value)
149{
150	return tpm_tis_spi_transfer(data, addr, len, NULL, value);
151}
152
153static int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result)
154{
155	__le16 result_le;
156	int rc;
157
158	rc = data->phy_ops->read_bytes(data, addr, sizeof(u16),
159				       (u8 *)&result_le);
160	if (!rc)
161		*result = le16_to_cpu(result_le);
162
163	return rc;
164}
165
166static int tpm_tis_spi_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
167{
168	__le32 result_le;
169	int rc;
170
171	rc = data->phy_ops->read_bytes(data, addr, sizeof(u32),
172				       (u8 *)&result_le);
173	if (!rc)
174		*result = le32_to_cpu(result_le);
175
176	return rc;
177}
178
179static int tpm_tis_spi_write32(struct tpm_tis_data *data, u32 addr, u32 value)
180{
181	__le32 value_le;
182	int rc;
183
184	value_le = cpu_to_le32(value);
185	rc = data->phy_ops->write_bytes(data, addr, sizeof(u32),
186					(u8 *)&value_le);
187
188	return rc;
189}
190
191static const struct tpm_tis_phy_ops tpm_spi_phy_ops = {
192	.read_bytes = tpm_tis_spi_read_bytes,
193	.write_bytes = tpm_tis_spi_write_bytes,
194	.read16 = tpm_tis_spi_read16,
195	.read32 = tpm_tis_spi_read32,
196	.write32 = tpm_tis_spi_write32,
197};
198
199static int tpm_tis_spi_probe(struct spi_device *dev)
200{
201	struct tpm_tis_spi_phy *phy;
202
203	phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_spi_phy),
204			   GFP_KERNEL);
205	if (!phy)
206		return -ENOMEM;
207
208	phy->spi_device = dev;
209
210	phy->iobuf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL);
211	if (!phy->iobuf)
212		return -ENOMEM;
213
214	return tpm_tis_core_init(&dev->dev, &phy->priv, -1, &tpm_spi_phy_ops,
215				 NULL);
216}
217
218static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume);
219
220static int tpm_tis_spi_remove(struct spi_device *dev)
221{
222	struct tpm_chip *chip = spi_get_drvdata(dev);
223
224	tpm_chip_unregister(chip);
225	tpm_tis_remove(chip);
226	return 0;
227}
228
229static const struct spi_device_id tpm_tis_spi_id[] = {
230	{"tpm_tis_spi", 0},
231	{}
232};
233MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);
234
235static const struct of_device_id of_tis_spi_match[] = {
236	{ .compatible = "st,st33htpm-spi", },
237	{ .compatible = "infineon,slb9670", },
238	{ .compatible = "tcg,tpm_tis-spi", },
239	{}
240};
241MODULE_DEVICE_TABLE(of, of_tis_spi_match);
242
243static const struct acpi_device_id acpi_tis_spi_match[] = {
244	{"SMO0768", 0},
245	{}
246};
247MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match);
248
249static struct spi_driver tpm_tis_spi_driver = {
250	.driver = {
251		.owner = THIS_MODULE,
252		.name = "tpm_tis_spi",
253		.pm = &tpm_tis_pm,
254		.of_match_table = of_match_ptr(of_tis_spi_match),
255		.acpi_match_table = ACPI_PTR(acpi_tis_spi_match),
256	},
257	.probe = tpm_tis_spi_probe,
258	.remove = tpm_tis_spi_remove,
259	.id_table = tpm_tis_spi_id,
260};
261module_spi_driver(tpm_tis_spi_driver);
262
263MODULE_DESCRIPTION("TPM Driver for native SPI access");
264MODULE_LICENSE("GPL");