| /* |
| * Copyright (C) 2011 Infineon Technologies |
| * |
| * Authors: |
| * Peter Huewe <huewe.external@infineon.com> |
| * |
| * Description: |
| * 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 1.2, revision 1.0 and the |
| * Infineon I2C Protocol Stack Specification v0.20. |
| * |
| * It is based on the Linux kernel driver tpm.c from Leendert van |
| * Dorn, Dave Safford, Reiner Sailer, and Kyleen Hall. |
| * |
| * Version: 2.1.1 |
| * |
| * See file CREDITS for list of people who contributed to this |
| * project. |
| * |
| * 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. |
| * |
| * 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, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, |
| * MA 02111-1307 USA |
| */ |
| |
| #include <asm/byteorder.h> |
| #include <common.h> |
| #include <stdint.h> |
| #include <string.h> |
| #include <types.h> |
| #include <clock.h> |
| #include <driver.h> |
| #include <init.h> |
| #include <i2c/i2c.h> |
| #include "tpm.h" |
| |
| #define DRIVER_NAME "tpm_i2c_infineon" |
| |
| #define BIOS_DEBUG KERN_DEBUG |
| |
| /* Address of the TPM on the I2C bus */ |
| #define TPM_I2C_ADDR 0x20 |
| |
| /* max. number of iterations after I2C NAK */ |
| #define MAX_COUNT 3 |
| |
| #define SLEEP_DURATION 60 /* in usec */ |
| |
| /* max. number of iterations after I2C NAK for 'long' commands |
| * we need this especially for sending TPM_READY, since the cleanup after the |
| * transtion to the ready state may take some time, but it is unpredictable |
| * how long it will take. |
| */ |
| #define MAX_COUNT_LONG 50 |
| |
| #define SLEEP_DURATION_LONG 210 /* in usec */ |
| |
| /* expected value for DIDVID register */ |
| #define TPM_TIS_I2C_DID_VID_9635 0x000b15d1L |
| #define TPM_TIS_I2C_DID_VID_9645 0x001a15d1L |
| |
| enum i2c_chip_type { |
| SLB9635, |
| SLB9645, |
| UNKNOWN, |
| }; |
| |
| static const char * const chip_name[] = { |
| [SLB9635] = "slb9635tt", |
| [SLB9645] = "slb9645tt", |
| [UNKNOWN] = "unknown/fallback to slb9635", |
| }; |
| |
| /* Structure to store I2C TPM specific stuff */ |
| struct tpm_inf_dev { |
| struct cdev cdev; |
| struct i2c_client *client; |
| uint8_t buf[TPM_BUFSIZE + sizeof(uint8_t)]; // max. buffer size + addr |
| enum i2c_chip_type chip_type; |
| }; |
| |
| static struct tpm_inf_dev tpm_dev; |
| |
| /* |
| * iic_tpm_read() - read from TPM register |
| * @addr: register address to read from |
| * @buffer: provided by caller |
| * @len: number of bytes to read |
| * |
| * Read len bytes from TPM register and put them into |
| * buffer (little-endian format, i.e. first byte is put into buffer[0]). |
| * |
| * NOTE: TPM is big-endian for multi-byte values. Multi-byte |
| * values have to be swapped. |
| * |
| * Return -1 on error, 0 on success. |
| */ |
| static int iic_tpm_read(uint8_t addr, uint8_t *buffer, size_t len) |
| { |
| int rc; |
| int count; |
| |
| if (!tpm_dev.client) |
| return -1; |
| if ((tpm_dev.chip_type == SLB9635) || (tpm_dev.chip_type == UNKNOWN)) { |
| /* slb9635 protocol should work in both cases */ |
| for (count = 0; count < MAX_COUNT; count++) { |
| rc = (i2c_master_send(tpm_dev.client, &addr, 1) <= 0); |
| if (rc == 0) |
| break; /* success, break to skip sleep */ |
| |
| udelay(SLEEP_DURATION); |
| } |
| |
| if (rc) |
| return -1; |
| |
| /* After the TPM has successfully received the register address |
| * it needs some time, thus we're sleeping here again, before |
| * retrieving the data |
| */ |
| for (count = 0; count < MAX_COUNT; count++) { |
| udelay(SLEEP_DURATION); |
| rc = (i2c_master_recv(tpm_dev.client, buffer, len) <= 0); |
| if (rc == 0) |
| break; /* success, break to skip sleep */ |
| |
| } |
| } else { |
| /* use a combined read for newer chips |
| * unfortunately the smbus functions are not suitable due to |
| * the 32 byte limit of the smbus. |
| * retries should usually not be needed, but are kept just to |
| * be safe on the safe side. |
| */ |
| struct i2c_msg msgs[] = { |
| { |
| .addr = tpm_dev.client->addr, |
| .flags = 0, |
| .buf = &addr, |
| .len = 1, |
| }, |
| { |
| .addr = tpm_dev.client->addr, |
| .flags = I2C_M_RD, |
| .buf = buffer, |
| .len = len, |
| }, |
| }; |
| |
| for (count = 0; count < MAX_COUNT; count++) { |
| rc = (i2c_transfer(tpm_dev.client->adapter, msgs, 2) != 2); |
| if (rc == 0) |
| break; /* break here to skip sleep */ |
| udelay(SLEEP_DURATION); |
| } |
| } |
| |
| /* take care of 'guard time' */ |
| udelay(SLEEP_DURATION); |
| if (rc) |
| return -1; |
| |
| return 0; |
| } |
| |
| static int iic_tpm_write_generic(uint8_t addr, uint8_t *buffer, size_t len, |
| unsigned int sleep_time, |
| uint8_t max_count) |
| { |
| int rc = 0; |
| int count; |
| |
| if (len > TPM_BUFSIZE) { |
| printk(BIOS_DEBUG "%s: Length %zd is too large\n", __func__, len); |
| return -1; |
| } |
| |
| /* prepare send buffer */ |
| tpm_dev.buf[0] = addr; |
| memcpy(&(tpm_dev.buf[1]), buffer, len); |
| |
| if (!tpm_dev.client) |
| return -1; |
| for (count = 0; count < max_count; count++) { |
| rc = (i2c_master_send(tpm_dev.client, |
| tpm_dev.buf, len + 1) <= 0); |
| if (rc == 0) |
| break; /* success, break to skip sleep */ |
| |
| udelay(sleep_time); |
| } |
| |
| /* take care of 'guard time' */ |
| udelay(SLEEP_DURATION); |
| if (rc) |
| return -1; |
| |
| return 0; |
| } |
| |
| /* |
| * iic_tpm_write() - write to TPM register |
| * @addr: register address to write to |
| * @buffer: containing data to be written |
| * @len: number of bytes to write |
| * |
| * Write len bytes from provided buffer to TPM register (little |
| * endian format, i.e. buffer[0] is written as first byte). |
| * |
| * NOTE: TPM is big-endian for multi-byte values. Multi-byte |
| * values have to be swapped. |
| * |
| * NOTE: use this function instead of the iic_tpm_write_generic function. |
| * |
| * Return -EIO on error, 0 on success |
| */ |
| static int iic_tpm_write(uint8_t addr, uint8_t *buffer, size_t len) |
| { |
| return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION, |
| MAX_COUNT); |
| } |
| |
| /* |
| * This function is needed especially for the cleanup situation after |
| * sending TPM_READY |
| * */ |
| static int iic_tpm_write_long(uint8_t addr, uint8_t *buffer, size_t len) |
| { |
| return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LONG, |
| MAX_COUNT_LONG); |
| } |
| |
| #define TPM_HEADER_SIZE 10 |
| |
| enum tis_access { |
| TPM_ACCESS_VALID = 0x80, |
| TPM_ACCESS_ACTIVE_LOCALITY = 0x20, |
| TPM_ACCESS_REQUEST_PENDING = 0x04, |
| TPM_ACCESS_REQUEST_USE = 0x02, |
| }; |
| |
| enum tis_status { |
| TPM_STS_VALID = 0x80, |
| TPM_STS_COMMAND_READY = 0x40, |
| TPM_STS_GO = 0x20, |
| TPM_STS_DATA_AVAIL = 0x10, |
| TPM_STS_DATA_EXPECT = 0x08, |
| }; |
| |
| #define TPM_ACCESS(l) (0x0000 | ((l) << 4)) |
| #define TPM_STS(l) (0x0001 | ((l) << 4)) |
| #define TPM_DATA_FIFO(l) (0x0005 | ((l) << 4)) |
| #define TPM_DID_VID(l) (0x0006 | ((l) << 4)) |
| |
| static int check_locality(struct tpm_chip *chip, int loc) |
| { |
| uint8_t buf; |
| |
| if (iic_tpm_read(TPM_ACCESS(loc), &buf, 1) < 0) |
| return -1; |
| |
| if ((buf & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) == |
| (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) { |
| chip->vendor.locality = loc; |
| return loc; |
| } |
| |
| return -1; |
| } |
| |
| static void release_locality(struct tpm_chip *chip, int loc, int force) |
| { |
| uint8_t buf; |
| if (iic_tpm_read(TPM_ACCESS(loc), &buf, 1) < 0) |
| return; |
| |
| if (force || (buf & (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) == |
| (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) { |
| buf = TPM_ACCESS_ACTIVE_LOCALITY; |
| iic_tpm_write(TPM_ACCESS(loc), &buf, 1); |
| } |
| } |
| |
| static int request_locality(struct tpm_chip *chip, int loc) |
| { |
| uint8_t buf = TPM_ACCESS_REQUEST_USE; |
| |
| if (check_locality(chip, loc) >= 0) |
| return loc; /* we already have the locality */ |
| |
| iic_tpm_write(TPM_ACCESS(loc), &buf, 1); |
| |
| /* wait for burstcount */ |
| int timeout = 2 * 1000; /* 2s timeout */ |
| while (timeout) { |
| if (check_locality(chip, loc) >= 0) |
| return loc; |
| mdelay(TPM_TIMEOUT); |
| timeout--; |
| } |
| |
| return -1; |
| } |
| |
| static uint8_t tpm_tis_i2c_status(struct tpm_chip *chip) |
| { |
| /* NOTE: Since I2C read may fail, return 0 in this case --> time-out */ |
| uint8_t buf; |
| if (iic_tpm_read(TPM_STS(chip->vendor.locality), &buf, 1) < 0) |
| return 0; |
| else |
| return buf; |
| } |
| |
| static void tpm_tis_i2c_ready(struct tpm_chip *chip) |
| { |
| /* this causes the current command to be aborted */ |
| uint8_t buf = TPM_STS_COMMAND_READY; |
| iic_tpm_write_long(TPM_STS(chip->vendor.locality), &buf, 1); |
| } |
| |
| static ssize_t get_burstcount(struct tpm_chip *chip) |
| { |
| ssize_t burstcnt; |
| uint8_t buf[3]; |
| |
| /* wait for burstcount */ |
| int timeout = 2 * 1000; /* 2s timeout */ |
| while (timeout) { |
| /* Note: STS is little endian */ |
| if (iic_tpm_read(TPM_STS(chip->vendor.locality) + 1, buf, 3) < 0) |
| burstcnt = 0; |
| else |
| burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0]; |
| |
| if (burstcnt) |
| return burstcnt; |
| mdelay(TPM_TIMEOUT); |
| timeout--; |
| } |
| return -1; |
| } |
| |
| static int wait_for_stat(struct tpm_chip *chip, uint8_t mask, int *status) |
| { |
| unsigned long timeout = 2 * 1024; |
| while (timeout) { |
| *status = tpm_tis_i2c_status(chip); |
| if ((*status & mask) == mask) |
| return 0; |
| mdelay(TPM_TIMEOUT); |
| timeout--; |
| } |
| |
| return -1; |
| } |
| |
| static int recv_data(struct tpm_chip *chip, uint8_t *buf, size_t count) |
| { |
| size_t size = 0; |
| |
| while (size < count) { |
| ssize_t burstcnt = get_burstcount(chip); |
| int rc; |
| |
| /* burstcount < 0 = TPM is busy */ |
| if (burstcnt < 0) |
| return burstcnt; |
| |
| /* limit received data to max. left */ |
| if (burstcnt > (count - size)) |
| burstcnt = count - size; |
| |
| rc = iic_tpm_read(TPM_DATA_FIFO(chip->vendor.locality), |
| &(buf[size]), |
| burstcnt); |
| if (rc == 0) |
| size += burstcnt; |
| |
| } |
| return size; |
| } |
| |
| static int tpm_tis_i2c_recv(struct tpm_chip *chip, uint8_t *buf, size_t count) |
| { |
| int size = 0; |
| uint32_t expected; |
| int status; |
| |
| if (count < TPM_HEADER_SIZE) { |
| size = -1; |
| goto out; |
| } |
| |
| /* read first 10 bytes, including tag, paramsize, and result */ |
| size = recv_data(chip, buf, TPM_HEADER_SIZE); |
| if (size < TPM_HEADER_SIZE) { |
| printk(BIOS_DEBUG "tpm_tis_i2c_recv: Unable to read header\n"); |
| goto out; |
| } |
| |
| memcpy(&expected, buf + TPM_RSP_SIZE_BYTE, sizeof(expected)); |
| expected = be32_to_cpu(expected); |
| if ((size_t)expected > count) { |
| size = -1; |
| goto out; |
| } |
| |
| size += recv_data(chip, &buf[TPM_HEADER_SIZE], |
| expected - TPM_HEADER_SIZE); |
| if (size < expected) { |
| printk(BIOS_DEBUG "tpm_tis_i2c_recv: Unable to " |
| "read remainder of result\n"); |
| size = -1; |
| goto out; |
| } |
| |
| wait_for_stat(chip, TPM_STS_VALID, &status); |
| if (status & TPM_STS_DATA_AVAIL) { /* retry? */ |
| printk(BIOS_DEBUG "tpm_tis_i2c_recv: Error left over data\n"); |
| size = -1; |
| goto out; |
| } |
| |
| out: |
| tpm_tis_i2c_ready(chip); |
| |
| return size; |
| } |
| |
| static int tpm_tis_i2c_send(struct tpm_chip *chip, uint8_t *buf, size_t len) |
| { |
| int status; |
| size_t count = 0; |
| uint8_t sts = TPM_STS_GO; |
| |
| if (len > TPM_BUFSIZE) |
| return -1; /* command is too long for our TPM, sorry */ |
| |
| status = tpm_tis_i2c_status(chip); |
| if ((status & TPM_STS_COMMAND_READY) == 0) { |
| tpm_tis_i2c_ready(chip); |
| if (wait_for_stat(chip, TPM_STS_COMMAND_READY, &status) < 0) |
| goto out_err; |
| } |
| |
| while (count < len - 1) { |
| ssize_t burstcnt = get_burstcount(chip); |
| |
| /* burstcount < 0 = TPM is busy */ |
| if (burstcnt < 0) |
| return burstcnt; |
| |
| if (burstcnt > (len-1-count)) |
| burstcnt = len-1-count; |
| |
| #ifdef CONFIG_TPM_I2C_BURST_LIMITATION |
| if (burstcnt > CONFIG_TPM_I2C_BURST_LIMITATION) |
| burstcnt = CONFIG_TPM_I2C_BURST_LIMITATION; |
| #endif /* CONFIG_TPM_I2C_BURST_LIMITATION */ |
| |
| if (iic_tpm_write(TPM_DATA_FIFO(chip->vendor.locality), |
| &(buf[count]), burstcnt) == 0) |
| count += burstcnt; |
| |
| wait_for_stat(chip, TPM_STS_VALID, &status); |
| if ((status & TPM_STS_DATA_EXPECT) == 0) |
| goto out_err; |
| } |
| |
| /* write last byte */ |
| iic_tpm_write(TPM_DATA_FIFO(chip->vendor.locality), &(buf[count]), 1); |
| |
| wait_for_stat(chip, TPM_STS_VALID, &status); |
| if ((status & TPM_STS_DATA_EXPECT) != 0) |
| goto out_err; |
| |
| /* go and do it */ |
| iic_tpm_write(TPM_STS(chip->vendor.locality), &sts, 1); |
| |
| return len; |
| |
| out_err: |
| tpm_tis_i2c_ready(chip); |
| |
| return -1; |
| } |
| |
| static struct tpm_vendor_specific tpm_tis_i2c = { |
| .status = tpm_tis_i2c_status, |
| .recv = tpm_tis_i2c_recv, |
| .send = tpm_tis_i2c_send, |
| .cancel = tpm_tis_i2c_ready, |
| .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID, |
| .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID, |
| .req_canceled = TPM_STS_COMMAND_READY, |
| }; |
| |
| /* Initialization of I2C TPM */ |
| |
| static int tpm_probe(struct device_d *dev) |
| { |
| uint32_t vendor; |
| struct tpm_chip *chip; |
| extern struct tpm_chip g_chip; |
| |
| chip = &g_chip; |
| memcpy(&chip->vendor, &tpm_tis_i2c, sizeof(struct tpm_vendor_specific)); |
| |
| tpm_dev.cdev.name = DRIVER_NAME; |
| tpm_dev.client = to_i2c_client(dev); |
| tpm_dev.cdev.size = 1024; // ? |
| tpm_dev.cdev.dev = dev; |
| |
| /* Disable interrupts (not supported) */ |
| chip->vendor.irq = 0; |
| |
| if (request_locality(chip, 0) != 0) |
| goto out_err; |
| |
| /* Read four bytes from DID_VID register */ |
| if (iic_tpm_read(TPM_DID_VID(0), (uint8_t *)&vendor, 4) < 0) |
| goto out_release; |
| |
| if (vendor == TPM_TIS_I2C_DID_VID_9645) { |
| tpm_dev.chip_type = SLB9645; |
| } else if (be32_to_cpu(vendor) == TPM_TIS_I2C_DID_VID_9635) { |
| tpm_dev.chip_type = SLB9635; |
| } else { |
| printk(BIOS_DEBUG "Vendor ID 0x%08x not recognized.\n", vendor); |
| goto out_release; |
| } |
| |
| printk(BIOS_DEBUG "1.2 TPM (chip type %s device-id 0x%X)\n", |
| chip_name[tpm_dev.chip_type], vendor >> 16); |
| |
| /* |
| * A timeout query to TPM can be placed here. |
| * Standard timeout values are used so far |
| */ |
| |
| devfs_create(&tpm_dev.cdev); |
| chip->is_open = 1; |
| |
| return 0; |
| |
| out_release: |
| release_locality(chip, 0, 1); |
| |
| out_err: |
| return -1; |
| } |
| |
| void tpm_vendor_cleanup(struct tpm_chip *chip) |
| { |
| release_locality(chip, chip->vendor.locality, 1); |
| } |
| |
| static struct driver_d tpm_i2c_infineon_driver = { |
| .name = DRIVER_NAME, |
| .probe = tpm_probe, |
| }; |
| |
| static int tpm_i2c_infineon_init(void) |
| { |
| register_driver(&tpm_i2c_infineon_driver); |
| return 0; |
| } |
| |
| device_initcall(tpm_i2c_infineon_init); |