diff options
Diffstat (limited to 'drivers/char/tpm/tpm_tis_spi.c')
| -rw-r--r-- | drivers/char/tpm/tpm_tis_spi.c | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c new file mode 100644 index 000000000..9914f6973 --- /dev/null +++ b/drivers/char/tpm/tpm_tis_spi.c @@ -0,0 +1,271 @@ +/* + * 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. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation, version 2 of the + * License. + */ + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/slab.h> +#include <linux/interrupt.h> +#include <linux/wait.h> +#include <linux/acpi.h> +#include <linux/freezer.h> + +#include <linux/spi/spi.h> +#include <linux/gpio.h> +#include <linux/of_irq.h> +#include <linux/of_gpio.h> +#include <linux/tpm.h> +#include "tpm.h" +#include "tpm_tis_core.h" + +#define MAX_SPI_FRAMESIZE 64 + +struct tpm_tis_spi_phy { + struct tpm_tis_data priv; + struct spi_device *spi_device; + u8 *iobuf; +}; + +static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *data) +{ + return container_of(data, struct tpm_tis_spi_phy, priv); +} + +static 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; + int i; + 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; + + if ((phy->iobuf[3] & 0x01) == 0) { + // handle SPI wait states + phy->iobuf[0] = 0; + + 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) + goto exit; + if (phy->iobuf[0] & 0x01) + break; + } + + if (i == TPM_RETRY) { + ret = -ETIMEDOUT; + goto exit; + } + } + + spi_xfer.cs_change = 0; + spi_xfer.len = transfer_len; + spi_xfer.delay_usecs = 5; + + if (in) { + spi_xfer.tx_buf = NULL; + } else if (out) { + 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); + 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); +} + +static 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; +} + +static 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; +} + +static 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; +} + +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->spi_device = dev; + + phy->iobuf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL); + if (!phy->iobuf) + return -ENOMEM; + + /* If the SPI device has an IRQ then use that */ + if (dev->irq > 0) + irq = dev->irq; + else + irq = -1; + + return tpm_tis_core_init(&dev->dev, &phy->priv, irq, &tpm_spi_phy_ops, + NULL); +} + +static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_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[] = { + {"tpm_tis_spi", 0}, + {} +}; +MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id); + +static const struct of_device_id of_tis_spi_match[] = { + { .compatible = "st,st33htpm-spi", }, + { .compatible = "infineon,slb9670", }, + { .compatible = "tcg,tpm_tis-spi", }, + {} +}; +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 = { + .owner = THIS_MODULE, + .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 = tpm_tis_spi_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"); |