mb/amb/birman*/gpio: remove configuration for VDD_MEM_VID[0,1]

[coreboot2.git] / src / drivers / i2c / tpm / tpm.c

/* SPDX-License-Identifier: GPL-2.0-only */

/*
 * 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
 */

#include <commonlib/endian.h>
#include <string.h>
#include <types.h>
#include <delay.h>
#include <console/console.h>
#include <device/i2c_simple.h>
#include <endian.h>
#include <timer.h>
#include <security/tpm/tis.h>
#include "tpm.h"

/* max. number of iterations after I2C NAK */
#define MAX_COUNT 3

#define SLEEP_DURATION 60 /* in usec */
#define SLEEP_DURATION_LONG 210 /* in usec */
#define SLEEP_DURATION_PROBE_MS 1000 /* in msec */

/* max. number of iterations after I2C NAK for 'long' commands
 * we need this especially for sending TPM_READY, since the cleanup after the
 * transition to the ready state may take some time, but it is unpredictable
 * how long it will take.
 */
#define MAX_COUNT_LONG 50

/* 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 {
        int bus;
        int locality;
        unsigned int addr;
        unsigned int sleep_short; /* Short sleep duration in usec */
        unsigned int sleep_long; /* Long sleep duration in usec */
        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.addr == 0)
                return -1;

        switch (tpm_dev.chip_type) {
        case SLB9635:
        case UNKNOWN:
                /* slb9635 protocol should work in both cases */
                for (count = 0; count < MAX_COUNT; count++) {
                        rc = i2c_write_raw(tpm_dev.bus, tpm_dev.addr,
                                           &addr, 1);
                        if (rc == 0)
                                break;  /* success, break to skip sleep */

                        udelay(tpm_dev.sleep_short);
                }

                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(tpm_dev.sleep_short);
                        rc = i2c_read_raw(tpm_dev.bus, tpm_dev.addr,
                                          buffer, len);
                        if (rc == 0)
                                break;  /* success, break to skip sleep */
                }
                break;

        default:
        {
                /* 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 aseg = { .flags = 0, .slave = tpm_dev.addr,
                                        .buf = &addr, .len = 1 };
                struct i2c_msg dseg = { .flags = I2C_M_RD,
                                        .slave = tpm_dev.addr,
                                        .buf = buffer, .len = len };
                for (count = 0; count < MAX_COUNT; count++) {
                        rc = i2c_transfer(tpm_dev.bus, &aseg, 1) ||
                             i2c_transfer(tpm_dev.bus, &dseg, 1);
                        if (rc == 0)
                                break;  /* break here to skip sleep */
                        udelay(tpm_dev.sleep_short);
                }
        }
        }

        /* take care of 'guard time' */
        udelay(tpm_dev.sleep_short);
        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.addr == 0)
                return -1;
        for (count = 0; count < max_count; count++) {
                rc = i2c_write_raw(tpm_dev.bus, tpm_dev.addr,
                                   tpm_dev.buf, len + 1);
                if (rc == 0)
                        break;  /* success, break to skip sleep */

                udelay(sleep_time);
        }

        /* take care of 'guard time' */
        udelay(tpm_dev.sleep_short);
        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, tpm_dev.sleep_short,
                                     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, tpm_dev.sleep_long,
                                     MAX_COUNT_LONG);
}

static int check_locality(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)) {
                tpm_dev.locality = loc;
                return loc;
        }

        return -1;
}

static void release_locality(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(int loc)
{
        uint8_t buf = TPM_ACCESS_REQUEST_USE;

        if (check_locality(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(loc) >= 0)
                        return loc;
                mdelay(TPM_TIMEOUT);
                timeout--;
        }

        return -1;
}

static uint8_t tpm_tis_i2c_status(void)
{
        /* NOTE: Since I2C read may fail, return 0 in this case --> time-out */
        uint8_t buf;
        if (iic_tpm_read(TPM_STS(tpm_dev.locality), &buf, 1) < 0)
                return 0;
        else if (buf == 0xff)   /* Some TPMs sometimes randomly return 0xff. */
                return 0;
        else
                return buf;
}

static void tpm_tis_i2c_ready(void)
{
        /* this causes the current command to be aborted */
        uint8_t buf = TPM_STS_COMMAND_READY;
        iic_tpm_write_long(TPM_STS(tpm_dev.locality), &buf, 1);
}

static ssize_t get_burstcount(void)
{
        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(tpm_dev.locality) + 1, buf, 3)
                        < 0)
                        burstcnt = 0;
                else
                        burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0];

                if (burstcnt && burstcnt != 0xffffff)
                        return burstcnt;
                mdelay(TPM_TIMEOUT);
                timeout--;
        }
        return -1;
}

static int wait_for_stat(uint8_t mask, int *status)
{
        unsigned long timeout = 2 * 1024;
        while (timeout) {
                *status = tpm_tis_i2c_status();
                if ((*status & mask) == mask)
                        return 0;
                mdelay(TPM_TIMEOUT);
                timeout--;
        }

        return -1;
}

static int recv_data(uint8_t *buf, size_t count)
{
        size_t size = 0;

        while (size < count) {
                ssize_t burstcnt = get_burstcount();
                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(tpm_dev.locality),
                                  &(buf[size]),
                                  burstcnt);
                if (rc == 0)
                        size += burstcnt;
        }
        return size;
}

static int tpm_tis_i2c_recv(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(buf, TPM_HEADER_SIZE);
        if (size < TPM_HEADER_SIZE) {
                printk(BIOS_DEBUG, "%s: Unable to read header\n", __func__);
                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(&buf[TPM_HEADER_SIZE], expected - TPM_HEADER_SIZE);
        if (size < expected) {
                printk(BIOS_DEBUG, "%s: Unable to read remainder of result\n", __func__);
                size = -1;
                goto out;
        }

        wait_for_stat(TPM_STS_VALID, &status);
        if (status & TPM_STS_DATA_AVAIL) {      /* retry? */
                printk(BIOS_DEBUG, "%s: Error left over data\n", __func__);
                size = -1;
                goto out;
        }

out:
        tpm_tis_i2c_ready();

        return size;
}

static int tpm_tis_i2c_send(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();
        if ((status & TPM_STS_COMMAND_READY) == 0) {
                tpm_tis_i2c_ready();
                if (wait_for_stat(TPM_STS_COMMAND_READY, &status) < 0)
                        goto out_err;
        }

        while (count < len - 1) {
                ssize_t burstcnt = get_burstcount();

                /* burstcount < 0 = TPM is busy */
                if (burstcnt < 0)
                        return burstcnt;

                if (burstcnt > (len-1-count))
                        burstcnt = len-1-count;

                if (iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality),
                                  &(buf[count]), burstcnt) == 0)
                        count += burstcnt;

                wait_for_stat(TPM_STS_VALID, &status);
                if ((status & TPM_STS_DATA_EXPECT) == 0)
                        goto out_err;
        }

        /* write last byte */
        iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality), &(buf[count]), 1);

        wait_for_stat(TPM_STS_VALID, &status);
        if ((status & TPM_STS_DATA_EXPECT) != 0)
                goto out_err;

        /* go and do it */
        iic_tpm_write(TPM_STS(tpm_dev.locality), &sts, 1);

        return len;

out_err:
        tpm_tis_i2c_ready();

        return -1;
}

/* Initialization of I2C TPM */

tpm_result_t tpm_vendor_probe(unsigned int bus, uint32_t addr, enum tpm_family *family)
{
        struct stopwatch sw;
        uint8_t buf = 0;
        int ret;
        long sw_run_duration = SLEEP_DURATION_PROBE_MS;

        /*
         * Infineon "I2C Protocol Stack Specification v0.20" is supposedly a
         * simple adoption of the LPC TIS Protocol to the I2C Bus, but looking
         * at "TCG PC Client Specific TIS" doesn't confirm that and Infineon's
         * specification isn't publicly available.
         *
         * Because it's unknown how to access information about TPM version of
         * the device in this case, the assumption is that whatever TPM version
         * is enabled at compile-time defines what the device supports. And
         * since this driver doesn't appear to be used with TPM 2 devices, the
         * check is written in a way to give TPM 1 preference even if support
         * for both versions is compiled in.
         */
        if (family != NULL)
                *family = CONFIG(TPM1) ? TPM_1 : TPM_2;

        tpm_dev.chip_type = UNKNOWN;
        tpm_dev.bus = bus;
        tpm_dev.addr = addr;
        tpm_dev.sleep_short = SLEEP_DURATION;
        tpm_dev.sleep_long = SLEEP_DURATION_LONG;

        /*
         * Probe TPM. Check if the TPM_ACCESS register's ValidSts bit is set(1)
         * If the bit remains clear(0) then claim that init has failed.
         */
        stopwatch_init_msecs_expire(&sw, sw_run_duration);
        do {
                ret = iic_tpm_read(TPM_ACCESS(0), &buf, 1);
                if (!ret && (buf & TPM_STS_VALID)) {
                        sw_run_duration = stopwatch_duration_msecs(&sw);
                        break;
                }
                udelay(SLEEP_DURATION);
        } while (!stopwatch_expired(&sw));

        printk(BIOS_INFO,
               "%s: ValidSts bit %s(%d) in TPM_ACCESS register after %ld ms\n",
               __func__, (buf & TPM_STS_VALID) ? "set" : "clear",
               (buf & TPM_STS_VALID) >> 7, sw_run_duration);

        /*
         * Claim failure if the ValidSts (bit 7) is clear.
         */
        if (!(buf & TPM_STS_VALID))
                return TPM_CB_FAIL;

        return TPM_SUCCESS;
}

tpm_result_t tpm_vendor_init(struct tpm_chip *chip, unsigned int bus, uint32_t dev_addr)
{
        uint32_t vendor;

        if (dev_addr == 0) {
                printk(BIOS_ERR, "%s: missing device address\n", __func__);
                return TPM_CB_INVALID_ARG;
        }

        tpm_dev.chip_type = UNKNOWN;
        tpm_dev.bus = bus;
        tpm_dev.addr = dev_addr;
        tpm_dev.sleep_short = SLEEP_DURATION;
        tpm_dev.sleep_long = SLEEP_DURATION_LONG;

        chip->req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID;
        chip->req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID;
        chip->req_canceled = TPM_STS_COMMAND_READY;
        chip->status = &tpm_tis_i2c_status;
        chip->recv = &tpm_tis_i2c_recv;
        chip->send = &tpm_tis_i2c_send;
        chip->cancel = &tpm_tis_i2c_ready;

        if (request_locality(0) != 0)
                return TPM_CB_FAIL;

        /* Read four bytes from DID_VID register */
        if (iic_tpm_read(TPM_DID_VID(0), (uint8_t *)&vendor, 4) < 0)
                goto out_err;

        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_err;
        }

        printk(BIOS_DEBUG, "I2C TPM %u:%02x (chip type %s device-id %#X)\n",
               tpm_dev.bus, tpm_dev.addr,
               chip_name[tpm_dev.chip_type], vendor >> 16);

        /*
         * A timeout query to TPM can be placed here.
         * Standard timeout values are used so far
         */

        return TPM_SUCCESS;

out_err:
        release_locality(0, 1);
        return TPM_CB_FAIL;
}