diff options
Diffstat (limited to 'drivers/char/tpm/st33zp24/spi.c')
| -rw-r--r-- | drivers/char/tpm/st33zp24/spi.c | 392 |
1 files changed, 392 insertions, 0 deletions
diff --git a/drivers/char/tpm/st33zp24/spi.c b/drivers/char/tpm/st33zp24/spi.c new file mode 100644 index 000000000000..7f4a5a46f0df --- /dev/null +++ b/drivers/char/tpm/st33zp24/spi.c @@ -0,0 +1,392 @@ +/* + * STMicroelectronics TPM SPI Linux driver for TPM ST33ZP24 + * Copyright (C) 2009 - 2015 STMicroelectronics + * + * 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; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/module.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 <linux/platform_data/st33zp24.h> + +#include "st33zp24.h" + +#define TPM_DATA_FIFO 0x24 +#define TPM_INTF_CAPABILITY 0x14 + +#define TPM_DUMMY_BYTE 0x00 + +#define MAX_SPI_LATENCY 15 +#define LOCALITY0 0 + +#define ST33ZP24_OK 0x5A +#define ST33ZP24_UNDEFINED_ERR 0x80 +#define ST33ZP24_BADLOCALITY 0x81 +#define ST33ZP24_TISREGISTER_UKNOWN 0x82 +#define ST33ZP24_LOCALITY_NOT_ACTIVATED 0x83 +#define ST33ZP24_HASH_END_BEFORE_HASH_START 0x84 +#define ST33ZP24_BAD_COMMAND_ORDER 0x85 +#define ST33ZP24_INCORECT_RECEIVED_LENGTH 0x86 +#define ST33ZP24_TPM_FIFO_OVERFLOW 0x89 +#define ST33ZP24_UNEXPECTED_READ_FIFO 0x8A +#define ST33ZP24_UNEXPECTED_WRITE_FIFO 0x8B +#define ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END 0x90 +#define ST33ZP24_DUMMY_BYTES 0x00 + +/* + * TPM command can be up to 2048 byte, A TPM response can be up to + * 1024 byte. + * Between command and response, there are latency byte (up to 15 + * usually on st33zp24 2 are enough). + * + * Overall when sending a command and expecting an answer we need if + * worst case: + * 2048 (for the TPM command) + 1024 (for the TPM answer). We need + * some latency byte before the answer is available (max 15). + * We have 2048 + 1024 + 15. + */ +#define ST33ZP24_SPI_BUFFER_SIZE (TPM_BUFSIZE + (TPM_BUFSIZE / 2) +\ + MAX_SPI_LATENCY) + + +struct st33zp24_spi_phy { + struct spi_device *spi_device; + struct spi_transfer spi_xfer; + u8 tx_buf[ST33ZP24_SPI_BUFFER_SIZE]; + u8 rx_buf[ST33ZP24_SPI_BUFFER_SIZE]; + + int io_lpcpd; + int latency; +}; + +static int st33zp24_status_to_errno(u8 code) +{ + switch (code) { + case ST33ZP24_OK: + return 0; + case ST33ZP24_UNDEFINED_ERR: + case ST33ZP24_BADLOCALITY: + case ST33ZP24_TISREGISTER_UKNOWN: + case ST33ZP24_LOCALITY_NOT_ACTIVATED: + case ST33ZP24_HASH_END_BEFORE_HASH_START: + case ST33ZP24_BAD_COMMAND_ORDER: + case ST33ZP24_UNEXPECTED_READ_FIFO: + case ST33ZP24_UNEXPECTED_WRITE_FIFO: + case ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END: + return -EPROTO; + case ST33ZP24_INCORECT_RECEIVED_LENGTH: + case ST33ZP24_TPM_FIFO_OVERFLOW: + return -EMSGSIZE; + case ST33ZP24_DUMMY_BYTES: + return -ENOSYS; + } + return code; +} + +/* + * st33zp24_spi_send + * Send byte to the TIS register according to the ST33ZP24 SPI protocol. + * @param: phy_id, the phy description + * @param: tpm_register, the tpm tis register where the data should be written + * @param: tpm_data, the tpm_data to write inside the tpm_register + * @param: tpm_size, The length of the data + * @return: should be zero if success else a negative error code. + */ +static int st33zp24_spi_send(void *phy_id, u8 tpm_register, u8 *tpm_data, + int tpm_size) +{ + u8 data = 0; + int total_length = 0, nbr_dummy_bytes = 0, ret = 0; + struct st33zp24_spi_phy *phy = phy_id; + struct spi_device *dev = phy->spi_device; + u8 *tx_buf = (u8 *)phy->spi_xfer.tx_buf; + u8 *rx_buf = phy->spi_xfer.rx_buf; + + /* Pre-Header */ + data = TPM_WRITE_DIRECTION | LOCALITY0; + memcpy(tx_buf + total_length, &data, sizeof(data)); + total_length++; + data = tpm_register; + memcpy(tx_buf + total_length, &data, sizeof(data)); + total_length++; + + if (tpm_size > 0 && tpm_register == TPM_DATA_FIFO) { + tx_buf[total_length++] = tpm_size >> 8; + tx_buf[total_length++] = tpm_size; + } + + memcpy(&tx_buf[total_length], tpm_data, tpm_size); + total_length += tpm_size; + + nbr_dummy_bytes = phy->latency; + memset(&tx_buf[total_length], TPM_DUMMY_BYTE, nbr_dummy_bytes); + + phy->spi_xfer.len = total_length + nbr_dummy_bytes; + + ret = spi_sync_transfer(dev, &phy->spi_xfer, 1); + if (ret == 0) + ret = rx_buf[total_length + nbr_dummy_bytes - 1]; + + return st33zp24_status_to_errno(ret); +} /* st33zp24_spi_send() */ + +/* + * read8_recv + * Recv byte from the TIS register according to the ST33ZP24 SPI protocol. + * @param: phy_id, the phy description + * @param: tpm_register, the tpm tis register where the data should be read + * @param: tpm_data, the TPM response + * @param: tpm_size, tpm TPM response size to read. + * @return: should be zero if success else a negative error code. + */ +static int read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size) +{ + u8 data = 0; + int total_length = 0, nbr_dummy_bytes, ret; + struct st33zp24_spi_phy *phy = phy_id; + struct spi_device *dev = phy->spi_device; + u8 *tx_buf = (u8 *)phy->spi_xfer.tx_buf; + u8 *rx_buf = phy->spi_xfer.rx_buf; + + /* Pre-Header */ + data = LOCALITY0; + memcpy(tx_buf + total_length, &data, sizeof(data)); + total_length++; + data = tpm_register; + memcpy(tx_buf + total_length, &data, sizeof(data)); + total_length++; + + nbr_dummy_bytes = phy->latency; + memset(&tx_buf[total_length], TPM_DUMMY_BYTE, + nbr_dummy_bytes + tpm_size); + + phy->spi_xfer.len = total_length + nbr_dummy_bytes + tpm_size; + + /* header + status byte + size of the data + status byte */ + ret = spi_sync_transfer(dev, &phy->spi_xfer, 1); + if (tpm_size > 0 && ret == 0) { + ret = rx_buf[total_length + nbr_dummy_bytes - 1]; + + memcpy(tpm_data, rx_buf + total_length + nbr_dummy_bytes, + tpm_size); + } + + return ret; +} /* read8_reg() */ + +/* + * st33zp24_spi_recv + * Recv byte from the TIS register according to the ST33ZP24 SPI protocol. + * @param: phy_id, the phy description + * @param: tpm_register, the tpm tis register where the data should be read + * @param: tpm_data, the TPM response + * @param: tpm_size, tpm TPM response size to read. + * @return: number of byte read successfully: should be one if success. + */ +static int st33zp24_spi_recv(void *phy_id, u8 tpm_register, u8 *tpm_data, + int tpm_size) +{ + int ret; + + ret = read8_reg(phy_id, tpm_register, tpm_data, tpm_size); + if (!st33zp24_status_to_errno(ret)) + return tpm_size; + return ret; +} /* st33zp24_spi_recv() */ + +static int evaluate_latency(void *phy_id) +{ + struct st33zp24_spi_phy *phy = phy_id; + int latency = 1, status = 0; + u8 data = 0; + + while (!status && latency < MAX_SPI_LATENCY) { + phy->latency = latency; + status = read8_reg(phy_id, TPM_INTF_CAPABILITY, &data, 1); + latency++; + } + return latency - 1; +} /* evaluate_latency() */ + +static const struct st33zp24_phy_ops spi_phy_ops = { + .send = st33zp24_spi_send, + .recv = st33zp24_spi_recv, +}; + +#ifdef CONFIG_OF +static int tpm_stm_spi_of_request_resources(struct st33zp24_spi_phy *phy) +{ + struct device_node *pp; + struct spi_device *dev = phy->spi_device; + int gpio; + int ret; + + pp = dev->dev.of_node; + if (!pp) { + dev_err(&dev->dev, "No platform data\n"); + return -ENODEV; + } + + /* Get GPIO from device tree */ + gpio = of_get_named_gpio(pp, "lpcpd-gpios", 0); + if (gpio < 0) { + dev_err(&dev->dev, + "Failed to retrieve lpcpd-gpios from dts.\n"); + phy->io_lpcpd = -1; + /* + * lpcpd pin is not specified. This is not an issue as + * power management can be also managed by TPM specific + * commands. So leave with a success status code. + */ + return 0; + } + /* GPIO request and configuration */ + ret = devm_gpio_request_one(&dev->dev, gpio, + GPIOF_OUT_INIT_HIGH, "TPM IO LPCPD"); + if (ret) { + dev_err(&dev->dev, "Failed to request lpcpd pin\n"); + return -ENODEV; + } + phy->io_lpcpd = gpio; + + return 0; +} +#else +static int tpm_stm_spi_of_request_resources(struct st33zp24_spi_phy *phy) +{ + return -ENODEV; +} +#endif + +static int tpm_stm_spi_request_resources(struct spi_device *dev, + struct st33zp24_spi_phy *phy) +{ + struct st33zp24_platform_data *pdata; + int ret; + + pdata = dev->dev.platform_data; + if (!pdata) { + dev_err(&dev->dev, "No platform data\n"); + return -ENODEV; + } + + /* store for late use */ + phy->io_lpcpd = pdata->io_lpcpd; + + if (gpio_is_valid(pdata->io_lpcpd)) { + ret = devm_gpio_request_one(&dev->dev, + pdata->io_lpcpd, GPIOF_OUT_INIT_HIGH, + "TPM IO_LPCPD"); + if (ret) { + dev_err(&dev->dev, "%s : reset gpio_request failed\n", + __FILE__); + return ret; + } + } + + return 0; +} + +/* + * tpm_st33_spi_probe initialize the TPM device + * @param: dev, the spi_device drescription (TPM SPI description). + * @return: 0 in case of success. + * or a negative value describing the error. + */ +static int +tpm_st33_spi_probe(struct spi_device *dev) +{ + int ret; + struct st33zp24_platform_data *pdata; + struct st33zp24_spi_phy *phy; + + /* Check SPI platform functionnalities */ + if (!dev) { + pr_info("%s: dev is NULL. Device is not accessible.\n", + __func__); + return -ENODEV; + } + + phy = devm_kzalloc(&dev->dev, sizeof(struct st33zp24_spi_phy), + GFP_KERNEL); + if (!phy) + return -ENOMEM; + + phy->spi_device = dev; + pdata = dev->dev.platform_data; + if (!pdata && dev->dev.of_node) { + ret = tpm_stm_spi_of_request_resources(phy); + if (ret) + return ret; + } else if (pdata) { + ret = tpm_stm_spi_request_resources(dev, phy); + if (ret) + return ret; + } + + phy->spi_xfer.tx_buf = phy->tx_buf; + phy->spi_xfer.rx_buf = phy->rx_buf; + + phy->latency = evaluate_latency(phy); + if (phy->latency <= 0) + return -ENODEV; + + return st33zp24_probe(phy, &spi_phy_ops, &dev->dev, dev->irq, + phy->io_lpcpd); +} + +/* + * tpm_st33_spi_remove remove the TPM device + * @param: client, the spi_device drescription (TPM SPI description). + * @return: 0 in case of success. + */ +static int tpm_st33_spi_remove(struct spi_device *dev) +{ + struct tpm_chip *chip = spi_get_drvdata(dev); + + return st33zp24_remove(chip); +} + +#ifdef CONFIG_OF +static const struct of_device_id of_st33zp24_spi_match[] = { + { .compatible = "st,st33zp24-spi", }, + {} +}; +MODULE_DEVICE_TABLE(of, of_st33zp24_spi_match); +#endif + +static SIMPLE_DEV_PM_OPS(st33zp24_spi_ops, st33zp24_pm_suspend, + st33zp24_pm_resume); + +static struct spi_driver tpm_st33_spi_driver = { + .driver = { + .owner = THIS_MODULE, + .name = TPM_ST33_SPI, + .pm = &st33zp24_spi_ops, + .of_match_table = of_match_ptr(of_st33zp24_spi_match), + }, + .probe = tpm_st33_spi_probe, + .remove = tpm_st33_spi_remove, +}; + +module_spi_driver(tpm_st33_spi_driver); + +MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)"); +MODULE_DESCRIPTION("STM TPM 1.2 SPI ST33 Driver"); +MODULE_VERSION("1.3.0"); +MODULE_LICENSE("GPL"); |