1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Author:
4 * Miquel Raynal <miquel.raynal@bootlin.com>
5 *
6 * Description:
7 * SPI-level driver for TCG/TIS TPM (trusted platform module).
8 * Specifications at www.trustedcomputinggroup.org
9 *
10 * This device driver implements the TPM interface as defined in
11 * the TCG SPI protocol stack version 2.0.
12 *
13 * It is based on the U-Boot driver tpm_tis_infineon_i2c.c.
14 */
15
16 #include <dm.h>
17 #include <fdtdec.h>
18 #include <log.h>
19 #include <spi.h>
20 #include <time.h>
21 #include <tpm-v2.h>
22 #include <linux/bitops.h>
23 #include <linux/delay.h>
24 #include <linux/errno.h>
25 #include <linux/compiler.h>
26 #include <linux/types.h>
27 #include <linux/unaligned/be_byteshift.h>
28 #include <asm-generic/gpio.h>
29
30 #include "tpm_tis.h"
31 #include "tpm_internal.h"
32
33 #define MAX_SPI_FRAMESIZE 64
34
35 /* Number of wait states to wait for */
36 #define TPM_WAIT_STATES 100
37
38 /**
39 * struct tpm_tis_chip_data - Non-discoverable TPM information
40 *
41 * @pcr_count: Number of PCR per bank
42 * @pcr_select_min: Size in octets of the pcrSelect array
43 */
44 struct tpm_tis_chip_data {
45 unsigned int pcr_count;
46 unsigned int pcr_select_min;
47 unsigned int time_before_first_cmd_ms;
48 };
49
50 /**
51 * tpm_tis_spi_read() - Read from TPM register
52 *
53 * @addr: register address to read from
54 * @buffer: provided by caller
55 * @len: number of bytes to read
56 *
57 * Read len bytes from TPM register and put them into
58 * buffer (little-endian format, i.e. first byte is put into buffer[0]).
59 *
60 * NOTE: TPM is big-endian for multi-byte values. Multi-byte
61 * values have to be swapped.
62 *
63 * Return: -EIO on error, 0 on success.
64 */
tpm_tis_spi_xfer(struct udevice * dev,u32 addr,const u8 * out,u8 * in,u16 len)65 static int tpm_tis_spi_xfer(struct udevice *dev, u32 addr, const u8 *out,
66 u8 *in, u16 len)
67 {
68 struct spi_slave *slave = dev_get_parent_priv(dev);
69 int transfer_len, ret;
70 u8 tx_buf[MAX_SPI_FRAMESIZE];
71 u8 rx_buf[MAX_SPI_FRAMESIZE];
72
73 if (in && out) {
74 log(LOGC_NONE, LOGL_ERR, "%s: can't do full duplex\n",
75 __func__);
76 return -EINVAL;
77 }
78
79 ret = spi_claim_bus(slave);
80 if (ret < 0) {
81 log(LOGC_NONE, LOGL_ERR, "%s: could not claim bus\n", __func__);
82 return ret;
83 }
84
85 while (len) {
86 /* Request */
87 transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
88 tx_buf[0] = (in ? BIT(7) : 0) | (transfer_len - 1);
89 tx_buf[1] = 0xD4;
90 tx_buf[2] = addr >> 8;
91 tx_buf[3] = addr;
92
93 ret = spi_xfer(slave, 4 * 8, tx_buf, rx_buf, SPI_XFER_BEGIN);
94 if (ret < 0) {
95 log(LOGC_NONE, LOGL_ERR,
96 "%s: spi request transfer failed (err: %d)\n",
97 __func__, ret);
98 goto release_bus;
99 }
100
101 /* Wait state */
102 if (!(rx_buf[3] & 0x1)) {
103 int i;
104
105 for (i = 0; i < TPM_WAIT_STATES; i++) {
106 ret = spi_xfer(slave, 1 * 8, NULL, rx_buf, 0);
107 if (ret) {
108 log(LOGC_NONE, LOGL_ERR,
109 "%s: wait state failed: %d\n",
110 __func__, ret);
111 goto release_bus;
112 }
113
114 if (rx_buf[0] & 0x1)
115 break;
116 }
117
118 if (i == TPM_WAIT_STATES) {
119 log(LOGC_NONE, LOGL_ERR,
120 "%s: timeout on wait state\n", __func__);
121 ret = -ETIMEDOUT;
122 goto release_bus;
123 }
124 }
125
126 /* Read/Write */
127 if (out) {
128 memcpy(tx_buf, out, transfer_len);
129 out += transfer_len;
130 }
131
132 ret = spi_xfer(slave, transfer_len * 8,
133 out ? tx_buf : NULL,
134 in ? rx_buf : NULL,
135 SPI_XFER_END);
136 if (ret) {
137 log(LOGC_NONE, LOGL_ERR,
138 "%s: spi read transfer failed (err: %d)\n",
139 __func__, ret);
140 goto release_bus;
141 }
142
143 if (in) {
144 memcpy(in, rx_buf, transfer_len);
145 in += transfer_len;
146 }
147
148 len -= transfer_len;
149 }
150
151 release_bus:
152 /* If an error occurred, release the chip by deasserting the CS */
153 if (ret < 0)
154 spi_xfer(slave, 0, NULL, NULL, SPI_XFER_END);
155
156 spi_release_bus(slave);
157
158 return ret;
159 }
160
tpm_tis_spi_read(struct udevice * dev,u32 addr,u16 len,u8 * in)161 static int tpm_tis_spi_read(struct udevice *dev, u32 addr, u16 len, u8 *in)
162 {
163 return tpm_tis_spi_xfer(dev, addr, NULL, in, len);
164 }
165
tpm_tis_spi_read32(struct udevice * dev,u32 addr,u32 * result)166 static int tpm_tis_spi_read32(struct udevice *dev, u32 addr, u32 *result)
167 {
168 __le32 result_le;
169 int ret;
170
171 ret = tpm_tis_spi_read(dev, addr, sizeof(u32), (u8 *)&result_le);
172 if (!ret)
173 *result = le32_to_cpu(result_le);
174
175 return ret;
176 }
177
tpm_tis_spi_write(struct udevice * dev,u32 addr,u16 len,const u8 * out)178 static int tpm_tis_spi_write(struct udevice *dev, u32 addr, u16 len, const u8 *out)
179 {
180 return tpm_tis_spi_xfer(dev, addr, out, NULL, len);
181 }
182
tpm_tis_spi_write32(struct udevice * dev,u32 addr,u32 value)183 static int tpm_tis_spi_write32(struct udevice *dev, u32 addr, u32 value)
184 {
185 __le32 value_le = cpu_to_le32(value);
186
187 return tpm_tis_spi_write(dev, addr, sizeof(value), (u8 *)&value_le);
188 }
189
190 static struct tpm_tis_phy_ops phy_ops = {
191 .read_bytes = tpm_tis_spi_read,
192 .write_bytes = tpm_tis_spi_write,
193 .read32 = tpm_tis_spi_read32,
194 .write32 = tpm_tis_spi_write32,
195 };
196
tpm_tis_spi_probe(struct udevice * dev)197 static int tpm_tis_spi_probe(struct udevice *dev)
198 {
199 struct tpm_tis_chip_data *drv_data = (void *)dev_get_driver_data(dev);
200 struct tpm_chip_priv *priv = dev_get_uclass_priv(dev);
201 int ret;
202
203 /* Use the TPM v2 stack */
204 priv->version = TPM_V2;
205
206 if (CONFIG_IS_ENABLED(DM_GPIO)) {
207 struct gpio_desc reset_gpio;
208
209 ret = gpio_request_by_name(dev, "reset-gpios", 0,
210 &reset_gpio, GPIOD_IS_OUT);
211 if (ret) {
212 /* legacy reset */
213 ret = gpio_request_by_name(dev, "gpio-reset", 0,
214 &reset_gpio, GPIOD_IS_OUT);
215 if (!ret) {
216 log(LOGC_NONE, LOGL_NOTICE,
217 "%s: gpio-reset is deprecated\n", __func__);
218 }
219 }
220
221 if (!ret) {
222 log(LOGC_NONE, LOGL_WARNING,
223 "%s: TPM gpio reset should not be used on secure production devices\n",
224 dev->name);
225 dm_gpio_set_value(&reset_gpio, 1);
226 mdelay(1);
227 dm_gpio_set_value(&reset_gpio, 0);
228 }
229 }
230
231 /* Ensure a minimum amount of time elapsed since reset of the TPM */
232 mdelay(drv_data->time_before_first_cmd_ms);
233
234 tpm_tis_ops_register(dev, &phy_ops);
235 ret = tpm_tis_init(dev);
236 if (ret)
237 goto err;
238
239 priv->pcr_count = drv_data->pcr_count;
240 priv->pcr_select_min = drv_data->pcr_select_min;
241 priv->version = TPM_V2;
242
243 return 0;
244 err:
245 return -EINVAL;
246 }
247
tpm_tis_spi_remove(struct udevice * udev)248 static int tpm_tis_spi_remove(struct udevice *udev)
249 {
250 return tpm_tis_cleanup(udev);
251 }
252
253 static const struct tpm_ops tpm_tis_spi_ops = {
254 .open = tpm_tis_open,
255 .close = tpm_tis_close,
256 .get_desc = tpm_tis_get_desc,
257 .send = tpm_tis_send,
258 .recv = tpm_tis_recv,
259 .cleanup = tpm_tis_cleanup,
260 };
261
262 static const struct tpm_tis_chip_data tpm_tis_std_chip_data = {
263 .pcr_count = 24,
264 .pcr_select_min = 3,
265 .time_before_first_cmd_ms = 30,
266 };
267
268 static const struct udevice_id tpm_tis_spi_ids[] = {
269 {
270 .compatible = "tcg,tpm_tis-spi",
271 .data = (ulong)&tpm_tis_std_chip_data,
272 },
273 { }
274 };
275
276 U_BOOT_DRIVER(tpm_tis_spi) = {
277 .name = "tpm_tis_spi",
278 .id = UCLASS_TPM,
279 .of_match = tpm_tis_spi_ids,
280 .ops = &tpm_tis_spi_ops,
281 .probe = tpm_tis_spi_probe,
282 .remove = tpm_tis_spi_remove,
283 .priv_auto = sizeof(struct tpm_chip),
284 };
285