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 */ 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 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 if (ret < 0) { 140 /* Deactivate chip select */ 141 memset(&spi_xfer, 0, sizeof(spi_xfer)); 142 spi_message_init(&m); 143 spi_message_add_tail(&spi_xfer, &m); 144 spi_sync_locked(phy->spi_device, &m); 145 } 146 147 spi_bus_unlock(phy->spi_device->master); 148 return ret; 149 } 150 151 static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr, 152 u16 len, u8 *result, enum tpm_tis_io_mode io_mode) 153 { 154 return tpm_tis_spi_transfer(data, addr, len, result, NULL); 155 } 156 157 static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr, 158 u16 len, const u8 *value, enum tpm_tis_io_mode io_mode) 159 { 160 return tpm_tis_spi_transfer(data, addr, len, NULL, value); 161 } 162 163 int tpm_tis_spi_init(struct spi_device *spi, struct tpm_tis_spi_phy *phy, 164 int irq, const struct tpm_tis_phy_ops *phy_ops) 165 { 166 phy->iobuf = devm_kmalloc(&spi->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL); 167 if (!phy->iobuf) 168 return -ENOMEM; 169 170 phy->spi_device = spi; 171 172 return tpm_tis_core_init(&spi->dev, &phy->priv, irq, phy_ops, NULL); 173 } 174 175 static const struct tpm_tis_phy_ops tpm_spi_phy_ops = { 176 .read_bytes = tpm_tis_spi_read_bytes, 177 .write_bytes = tpm_tis_spi_write_bytes, 178 }; 179 180 static int tpm_tis_spi_probe(struct spi_device *dev) 181 { 182 struct tpm_tis_spi_phy *phy; 183 int irq; 184 185 phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_spi_phy), 186 GFP_KERNEL); 187 if (!phy) 188 return -ENOMEM; 189 190 phy->flow_control = tpm_tis_spi_flow_control; 191 192 /* If the SPI device has an IRQ then use that */ 193 if (dev->irq > 0) 194 irq = dev->irq; 195 else 196 irq = -1; 197 198 init_completion(&phy->ready); 199 return tpm_tis_spi_init(dev, phy, irq, &tpm_spi_phy_ops); 200 } 201 202 typedef int (*tpm_tis_spi_probe_func)(struct spi_device *); 203 204 static int tpm_tis_spi_driver_probe(struct spi_device *spi) 205 { 206 const struct spi_device_id *spi_dev_id = spi_get_device_id(spi); 207 tpm_tis_spi_probe_func probe_func; 208 209 probe_func = of_device_get_match_data(&spi->dev); 210 if (!probe_func) { 211 if (spi_dev_id) { 212 probe_func = (tpm_tis_spi_probe_func)spi_dev_id->driver_data; 213 if (!probe_func) 214 return -ENODEV; 215 } else 216 probe_func = tpm_tis_spi_probe; 217 } 218 219 return probe_func(spi); 220 } 221 222 static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_spi_resume); 223 224 static void tpm_tis_spi_remove(struct spi_device *dev) 225 { 226 struct tpm_chip *chip = spi_get_drvdata(dev); 227 228 tpm_chip_unregister(chip); 229 tpm_tis_remove(chip); 230 } 231 232 static const struct spi_device_id tpm_tis_spi_id[] = { 233 { "st33htpm-spi", (unsigned long)tpm_tis_spi_probe }, 234 { "slb9670", (unsigned long)tpm_tis_spi_probe }, 235 { "tpm_tis_spi", (unsigned long)tpm_tis_spi_probe }, 236 { "tpm_tis-spi", (unsigned long)tpm_tis_spi_probe }, 237 { "cr50", (unsigned long)cr50_spi_probe }, 238 {} 239 }; 240 MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id); 241 242 static const struct of_device_id of_tis_spi_match[] __maybe_unused = { 243 { .compatible = "st,st33htpm-spi", .data = tpm_tis_spi_probe }, 244 { .compatible = "infineon,slb9670", .data = tpm_tis_spi_probe }, 245 { .compatible = "tcg,tpm_tis-spi", .data = tpm_tis_spi_probe }, 246 { .compatible = "google,cr50", .data = cr50_spi_probe }, 247 {} 248 }; 249 MODULE_DEVICE_TABLE(of, of_tis_spi_match); 250 251 static const struct acpi_device_id acpi_tis_spi_match[] __maybe_unused = { 252 {"SMO0768", 0}, 253 {} 254 }; 255 MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match); 256 257 static struct spi_driver tpm_tis_spi_driver = { 258 .driver = { 259 .name = "tpm_tis_spi", 260 .pm = &tpm_tis_pm, 261 .of_match_table = of_match_ptr(of_tis_spi_match), 262 .acpi_match_table = ACPI_PTR(acpi_tis_spi_match), 263 .probe_type = PROBE_PREFER_ASYNCHRONOUS, 264 }, 265 .probe = tpm_tis_spi_driver_probe, 266 .remove = tpm_tis_spi_remove, 267 .id_table = tpm_tis_spi_id, 268 }; 269 module_spi_driver(tpm_tis_spi_driver); 270 271 MODULE_DESCRIPTION("TPM Driver for native SPI access"); 272 MODULE_LICENSE("GPL"); 273