| // 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) |
| { |
| 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) |
| { |
| return tpm_tis_spi_transfer(data, addr, len, NULL, value); |
| } |
| |
| int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result) |
| { |
| __le16 result_le; |
| int rc; |
| |
| rc = data->phy_ops->read_bytes(data, addr, sizeof(u16), |
| (u8 *)&result_le); |
| if (!rc) |
| *result = le16_to_cpu(result_le); |
| |
| return rc; |
| } |
| |
| int tpm_tis_spi_read32(struct tpm_tis_data *data, u32 addr, u32 *result) |
| { |
| __le32 result_le; |
| int rc; |
| |
| rc = data->phy_ops->read_bytes(data, addr, sizeof(u32), |
| (u8 *)&result_le); |
| if (!rc) |
| *result = le32_to_cpu(result_le); |
| |
| return rc; |
| } |
| |
| int tpm_tis_spi_write32(struct tpm_tis_data *data, u32 addr, u32 value) |
| { |
| __le32 value_le; |
| int rc; |
| |
| value_le = cpu_to_le32(value); |
| rc = data->phy_ops->write_bytes(data, addr, sizeof(u32), |
| (u8 *)&value_le); |
| |
| return rc; |
| } |
| |
| 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, |
| .read16 = tpm_tis_spi_read16, |
| .read32 = tpm_tis_spi_read32, |
| .write32 = tpm_tis_spi_write32, |
| }; |
| |
| 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 int tpm_tis_spi_remove(struct spi_device *dev) |
| { |
| struct tpm_chip *chip = spi_get_drvdata(dev); |
| |
| tpm_chip_unregister(chip); |
| tpm_tis_remove(chip); |
| return 0; |
| } |
| |
| 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 }, |
| { "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"); |