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
42 struct tpm_tis_spi_phy {
43 struct tpm_tis_data priv;
44 struct spi_device *spi_device;
45 u8 *iobuf;
46 };
47
to_tpm_tis_spi_phy(struct tpm_tis_data * data)48 static 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
tpm_tis_spi_transfer(struct tpm_tis_data * data,u32 addr,u16 len,u8 * in,const u8 * out)53 static 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
132 exit:
133 spi_bus_unlock(phy->spi_device->master);
134 return ret;
135 }
136
tpm_tis_spi_read_bytes(struct tpm_tis_data * data,u32 addr,u16 len,u8 * result)137 static 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
tpm_tis_spi_write_bytes(struct tpm_tis_data * data,u32 addr,u16 len,const u8 * value)143 static 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
tpm_tis_spi_read16(struct tpm_tis_data * data,u32 addr,u16 * result)149 static 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
tpm_tis_spi_read32(struct tpm_tis_data * data,u32 addr,u32 * result)162 static 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
tpm_tis_spi_write32(struct tpm_tis_data * data,u32 addr,u32 value)175 static 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
187 static 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
tpm_tis_spi_probe(struct spi_device * dev)195 static 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
221 static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume);
222
tpm_tis_spi_remove(struct spi_device * dev)223 static 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
232 static const struct spi_device_id tpm_tis_spi_id[] = {
233 {"tpm_tis_spi", 0},
234 {}
235 };
236 MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);
237
238 static 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 };
244 MODULE_DEVICE_TABLE(of, of_tis_spi_match);
245
246 static const struct acpi_device_id acpi_tis_spi_match[] = {
247 {"SMO0768", 0},
248 {}
249 };
250 MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match);
251
252 static 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 };
264 module_spi_driver(tpm_tis_spi_driver);
265
266 MODULE_DESCRIPTION("TPM Driver for native SPI access");
267 MODULE_LICENSE("GPL");
268