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/acpi.h>
24 #include <linux/completion.h>
25 #include <linux/init.h>
26 #include <linux/interrupt.h>
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/slab.h>
30
31 #include <linux/of_device.h>
32 #include <linux/spi/spi.h>
33 #include <linux/tpm.h>
34
35 #include "tpm.h"
36 #include "tpm_tis_core.h"
37 #include "tpm_tis_spi.h"
38
39 #define MAX_SPI_FRAMESIZE 64
40
41 /*
42 * TCG SPI flow control is documented in section 6.4 of the spec[1]. In short,
43 * keep trying to read from the device until MISO goes high indicating the
44 * wait state has ended.
45 *
46 * [1] https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
47 */
tpm_tis_spi_flow_control(struct tpm_tis_spi_phy * phy,struct spi_transfer * spi_xfer)48 static int tpm_tis_spi_flow_control(struct tpm_tis_spi_phy *phy,
49 struct spi_transfer *spi_xfer)
50 {
51 struct spi_message m;
52 int ret, i;
53
54 if ((phy->iobuf[3] & 0x01) == 0) {
55 // handle SPI wait states
56 for (i = 0; i < TPM_RETRY; i++) {
57 spi_xfer->len = 1;
58 spi_message_init(&m);
59 spi_message_add_tail(spi_xfer, &m);
60 ret = spi_sync_locked(phy->spi_device, &m);
61 if (ret < 0)
62 return ret;
63 if (phy->iobuf[0] & 0x01)
64 break;
65 }
66
67 if (i == TPM_RETRY)
68 return -ETIMEDOUT;
69 }
70
71 return 0;
72 }
73
tpm_tis_spi_transfer(struct tpm_tis_data * data,u32 addr,u16 len,u8 * in,const u8 * out)74 int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
75 u8 *in, const u8 *out)
76 {
77 struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
78 int ret = 0;
79 struct spi_message m;
80 struct spi_transfer spi_xfer;
81 u8 transfer_len;
82
83 spi_bus_lock(phy->spi_device->master);
84
85 while (len) {
86 transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
87
88 phy->iobuf[0] = (in ? 0x80 : 0) | (transfer_len - 1);
89 phy->iobuf[1] = 0xd4;
90 phy->iobuf[2] = addr >> 8;
91 phy->iobuf[3] = addr;
92
93 memset(&spi_xfer, 0, sizeof(spi_xfer));
94 spi_xfer.tx_buf = phy->iobuf;
95 spi_xfer.rx_buf = phy->iobuf;
96 spi_xfer.len = 4;
97 spi_xfer.cs_change = 1;
98
99 spi_message_init(&m);
100 spi_message_add_tail(&spi_xfer, &m);
101 ret = spi_sync_locked(phy->spi_device, &m);
102 if (ret < 0)
103 goto exit;
104
105 /* Flow control transfers are receive only */
106 spi_xfer.tx_buf = NULL;
107 ret = phy->flow_control(phy, &spi_xfer);
108 if (ret < 0)
109 goto exit;
110
111 spi_xfer.cs_change = 0;
112 spi_xfer.len = transfer_len;
113 spi_xfer.delay.value = 5;
114 spi_xfer.delay.unit = SPI_DELAY_UNIT_USECS;
115
116 if (out) {
117 spi_xfer.tx_buf = phy->iobuf;
118 spi_xfer.rx_buf = NULL;
119 memcpy(phy->iobuf, out, transfer_len);
120 out += transfer_len;
121 }
122
123 spi_message_init(&m);
124 spi_message_add_tail(&spi_xfer, &m);
125 reinit_completion(&phy->ready);
126 ret = spi_sync_locked(phy->spi_device, &m);
127 if (ret < 0)
128 goto exit;
129
130 if (in) {
131 memcpy(in, phy->iobuf, transfer_len);
132 in += transfer_len;
133 }
134
135 len -= transfer_len;
136 }
137
138 exit:
139 spi_bus_unlock(phy->spi_device->master);
140 return ret;
141 }
142
tpm_tis_spi_read_bytes(struct tpm_tis_data * data,u32 addr,u16 len,u8 * result,enum tpm_tis_io_mode io_mode)143 static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,
144 u16 len, u8 *result, enum tpm_tis_io_mode io_mode)
145 {
146 return tpm_tis_spi_transfer(data, addr, len, result, NULL);
147 }
148
tpm_tis_spi_write_bytes(struct tpm_tis_data * data,u32 addr,u16 len,const u8 * value,enum tpm_tis_io_mode io_mode)149 static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,
150 u16 len, const u8 *value, enum tpm_tis_io_mode io_mode)
151 {
152 return tpm_tis_spi_transfer(data, addr, len, NULL, value);
153 }
154
tpm_tis_spi_init(struct spi_device * spi,struct tpm_tis_spi_phy * phy,int irq,const struct tpm_tis_phy_ops * phy_ops)155 int tpm_tis_spi_init(struct spi_device *spi, struct tpm_tis_spi_phy *phy,
156 int irq, const struct tpm_tis_phy_ops *phy_ops)
157 {
158 phy->iobuf = devm_kmalloc(&spi->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL);
159 if (!phy->iobuf)
160 return -ENOMEM;
161
162 phy->spi_device = spi;
163
164 return tpm_tis_core_init(&spi->dev, &phy->priv, irq, phy_ops, NULL);
165 }
166
167 static const struct tpm_tis_phy_ops tpm_spi_phy_ops = {
168 .read_bytes = tpm_tis_spi_read_bytes,
169 .write_bytes = tpm_tis_spi_write_bytes,
170 };
171
tpm_tis_spi_probe(struct spi_device * dev)172 static int tpm_tis_spi_probe(struct spi_device *dev)
173 {
174 struct tpm_tis_spi_phy *phy;
175 int irq;
176
177 phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_spi_phy),
178 GFP_KERNEL);
179 if (!phy)
180 return -ENOMEM;
181
182 phy->flow_control = tpm_tis_spi_flow_control;
183
184 /* If the SPI device has an IRQ then use that */
185 if (dev->irq > 0)
186 irq = dev->irq;
187 else
188 irq = -1;
189
190 init_completion(&phy->ready);
191 return tpm_tis_spi_init(dev, phy, irq, &tpm_spi_phy_ops);
192 }
193
194 typedef int (*tpm_tis_spi_probe_func)(struct spi_device *);
195
tpm_tis_spi_driver_probe(struct spi_device * spi)196 static int tpm_tis_spi_driver_probe(struct spi_device *spi)
197 {
198 const struct spi_device_id *spi_dev_id = spi_get_device_id(spi);
199 tpm_tis_spi_probe_func probe_func;
200
201 probe_func = of_device_get_match_data(&spi->dev);
202 if (!probe_func) {
203 if (spi_dev_id) {
204 probe_func = (tpm_tis_spi_probe_func)spi_dev_id->driver_data;
205 if (!probe_func)
206 return -ENODEV;
207 } else
208 probe_func = tpm_tis_spi_probe;
209 }
210
211 return probe_func(spi);
212 }
213
214 static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_spi_resume);
215
tpm_tis_spi_remove(struct spi_device * dev)216 static void tpm_tis_spi_remove(struct spi_device *dev)
217 {
218 struct tpm_chip *chip = spi_get_drvdata(dev);
219
220 tpm_chip_unregister(chip);
221 tpm_tis_remove(chip);
222 }
223
224 static const struct spi_device_id tpm_tis_spi_id[] = {
225 { "st33htpm-spi", (unsigned long)tpm_tis_spi_probe },
226 { "slb9670", (unsigned long)tpm_tis_spi_probe },
227 { "tpm_tis_spi", (unsigned long)tpm_tis_spi_probe },
228 { "tpm_tis-spi", (unsigned long)tpm_tis_spi_probe },
229 { "cr50", (unsigned long)cr50_spi_probe },
230 {}
231 };
232 MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);
233
234 static const struct of_device_id of_tis_spi_match[] = {
235 { .compatible = "st,st33htpm-spi", .data = tpm_tis_spi_probe },
236 { .compatible = "infineon,slb9670", .data = tpm_tis_spi_probe },
237 { .compatible = "tcg,tpm_tis-spi", .data = tpm_tis_spi_probe },
238 { .compatible = "google,cr50", .data = cr50_spi_probe },
239 {}
240 };
241 MODULE_DEVICE_TABLE(of, of_tis_spi_match);
242
243 static const struct acpi_device_id acpi_tis_spi_match[] = {
244 {"SMO0768", 0},
245 {}
246 };
247 MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match);
248
249 static struct spi_driver tpm_tis_spi_driver = {
250 .driver = {
251 .name = "tpm_tis_spi",
252 .pm = &tpm_tis_pm,
253 .of_match_table = of_match_ptr(of_tis_spi_match),
254 .acpi_match_table = ACPI_PTR(acpi_tis_spi_match),
255 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
256 },
257 .probe = tpm_tis_spi_driver_probe,
258 .remove = tpm_tis_spi_remove,
259 .id_table = tpm_tis_spi_id,
260 };
261 module_spi_driver(tpm_tis_spi_driver);
262
263 MODULE_DESCRIPTION("TPM Driver for native SPI access");
264 MODULE_LICENSE("GPL");
265