// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2015 Infineon Technologies AG * Copyright (C) 2016 STMicroelectronics SAS * * Authors: * Peter Huewe <peter.huewe@infineon.com> * Christophe Ricard <christophe-h.ricard@st.com> * * Maintained by: <tpmdd-devel@lists.sourceforge.net> * * Device driver for TCG/TCPA TPM (trusted platform module). * Specifications at www.trustedcomputinggroup.org * * This device driver implements the TPM interface as defined in * the TCG TPM Interface Spec version 1.3, revision 27 via _raw/native * SPI access_. * * It is based on the original tpm_tis device driver from Leendert van * Dorn and Kyleen Hall and Jarko Sakkinnen. */ #include <linux/acpi.h> #include <linux/completion.h> #include <linux/init.h> #include <linux/interrupt.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/of_device.h> #include <linux/spi/spi.h> #include <linux/tpm.h> #include "tpm.h" #include "tpm_tis_core.h" #include "tpm_tis_spi.h" #define MAX_SPI_FRAMESIZE 64 /* * TCG SPI flow control is documented in section 6.4 of the spec[1]. In short, * keep trying to read from the device until MISO goes high indicating the * wait state has ended. * * [1] https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/ */ static int tpm_tis_spi_flow_control(struct tpm_tis_spi_phy *phy, struct spi_transfer *spi_xfer) { struct spi_message m; int ret, i; if ((phy->iobuf[3] & 0x01) == 0) { // handle SPI wait states for (i = 0; i < TPM_RETRY; i++) { spi_xfer->len = 1; spi_message_init(&m); spi_message_add_tail(spi_xfer, &m); ret = spi_sync_locked(phy->spi_device, &m); if (ret < 0) return ret; if (phy->iobuf[0] & 0x01) break; } if (i == TPM_RETRY) return -ETIMEDOUT; } return 0; } int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, u8 *in, const u8 *out) { struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data); int ret = 0; struct spi_message m; struct spi_transfer spi_xfer; u8 transfer_len; spi_bus_lock(phy->spi_device->master); while (len) { transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE); phy->iobuf[0] = (in ? 0x80 : 0) | (transfer_len - 1); phy->iobuf[1] = 0xd4; phy->iobuf[2] = addr >> 8; phy->iobuf[3] = addr; memset(&spi_xfer, 0, sizeof(spi_xfer)); spi_xfer.tx_buf = phy->iobuf; spi_xfer.rx_buf = phy->iobuf; spi_xfer.len = 4; spi_xfer.cs_change = 1; spi_message_init(&m); spi_message_add_tail(&spi_xfer, &m); ret = spi_sync_locked(phy->spi_device, &m); if (ret < 0) goto exit; /* Flow control transfers are receive only */ spi_xfer.tx_buf = NULL; ret = phy->flow_control(phy, &spi_xfer); if (ret < 0) goto exit; spi_xfer.cs_change = 0; spi_xfer.len = transfer_len; spi_xfer.delay.value = 5; spi_xfer.delay.unit = SPI_DELAY_UNIT_USECS; if (out) { spi_xfer.tx_buf = phy->iobuf; spi_xfer.rx_buf = NULL; memcpy(phy->iobuf, out, transfer_len); out += transfer_len; } spi_message_init(&m); spi_message_add_tail(&spi_xfer, &m); reinit_completion(&phy->ready); ret = spi_sync_locked(phy->spi_device, &m); if (ret < 0) goto exit; if (in) { memcpy(in, phy->iobuf, transfer_len); in += transfer_len; } len -= transfer_len; } exit: spi_bus_unlock(phy->spi_device->master); return ret; } static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr, u16 len, u8 *result, enum tpm_tis_io_mode io_mode) { return tpm_tis_spi_transfer(data, addr, len, result, NULL); } static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr, u16 len, const u8 *value, enum tpm_tis_io_mode io_mode) { return tpm_tis_spi_transfer(data, addr, len, NULL, value); } int tpm_tis_spi_init(struct spi_device *spi, struct tpm_tis_spi_phy *phy, int irq, const struct tpm_tis_phy_ops *phy_ops) { phy->iobuf = devm_kmalloc(&spi->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL); if (!phy->iobuf) return -ENOMEM; phy->spi_device = spi; return tpm_tis_core_init(&spi->dev, &phy->priv, irq, phy_ops, NULL); } static const struct tpm_tis_phy_ops tpm_spi_phy_ops = { .read_bytes = tpm_tis_spi_read_bytes, .write_bytes = tpm_tis_spi_write_bytes, }; static int tpm_tis_spi_probe(struct spi_device *dev) { struct tpm_tis_spi_phy *phy; int irq; phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_spi_phy), GFP_KERNEL); if (!phy) return -ENOMEM; phy->flow_control = tpm_tis_spi_flow_control; /* If the SPI device has an IRQ then use that */ if (dev->irq > 0) irq = dev->irq; else irq = -1; init_completion(&phy->ready); return tpm_tis_spi_init(dev, phy, irq, &tpm_spi_phy_ops); } typedef int (*tpm_tis_spi_probe_func)(struct spi_device *); static int tpm_tis_spi_driver_probe(struct spi_device *spi) { const struct spi_device_id *spi_dev_id = spi_get_device_id(spi); tpm_tis_spi_probe_func probe_func; probe_func = of_device_get_match_data(&spi->dev); if (!probe_func) { if (spi_dev_id) { probe_func = (tpm_tis_spi_probe_func)spi_dev_id->driver_data; if (!probe_func) return -ENODEV; } else probe_func = tpm_tis_spi_probe; } return probe_func(spi); } static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_spi_resume); static void tpm_tis_spi_remove(struct spi_device *dev) { struct tpm_chip *chip = spi_get_drvdata(dev); tpm_chip_unregister(chip); tpm_tis_remove(chip); } static const struct spi_device_id tpm_tis_spi_id[] = { { "st33htpm-spi", (unsigned long)tpm_tis_spi_probe }, { "slb9670", (unsigned long)tpm_tis_spi_probe }, { "tpm_tis_spi", (unsigned long)tpm_tis_spi_probe }, { "tpm_tis-spi", (unsigned long)tpm_tis_spi_probe }, { "cr50", (unsigned long)cr50_spi_probe }, {} }; MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id); static const struct of_device_id of_tis_spi_match[] = { { .compatible = "st,st33htpm-spi", .data = tpm_tis_spi_probe }, { .compatible = "infineon,slb9670", .data = tpm_tis_spi_probe }, { .compatible = "tcg,tpm_tis-spi", .data = tpm_tis_spi_probe }, { .compatible = "google,cr50", .data = cr50_spi_probe }, {} }; MODULE_DEVICE_TABLE(of, of_tis_spi_match); static const struct acpi_device_id acpi_tis_spi_match[] = { {"SMO0768", 0}, {} }; MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match); static struct spi_driver tpm_tis_spi_driver = { .driver = { .name = "tpm_tis_spi", .pm = &tpm_tis_pm, .of_match_table = of_match_ptr(of_tis_spi_match), .acpi_match_table = ACPI_PTR(acpi_tis_spi_match), .probe_type = PROBE_PREFER_ASYNCHRONOUS, }, .probe = tpm_tis_spi_driver_probe, .remove = tpm_tis_spi_remove, .id_table = tpm_tis_spi_id, }; module_spi_driver(tpm_tis_spi_driver); MODULE_DESCRIPTION("TPM Driver for native SPI access"); MODULE_LICENSE("GPL");