// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2005, 2006 IBM Corporation
 * Copyright (C) 2014, 2015 Intel Corporation
 *
 * Authors:
 * Leendert van Doorn <leendert@watson.ibm.com>
 * Kylene Hall <kjhall@us.ibm.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 1.2, revision 1.0.
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/pnp.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/acpi.h>
#include <linux/freezer.h>
#include <linux/dmi.h>
#include "tpm.h"
#include "tpm_tis_core.h"

#define TPM_TIS_MAX_UNHANDLED_IRQS      1000

static void tpm_tis_clkrun_enable(struct tpm_chip *chip, bool value);

static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask,
                                        bool check_cancel, bool *canceled)
{
        u8 status = chip->ops->status(chip);

        *canceled = false;
        if ((status & mask) == mask)
                return true;
        if (check_cancel && chip->ops->req_canceled(chip, status)) {
                *canceled = true;
                return true;
        }
        return false;
}

static u8 tpm_tis_filter_sts_mask(u8 int_mask, u8 sts_mask)
{
        if (!(int_mask & TPM_INTF_STS_VALID_INT))
                sts_mask &= ~TPM_STS_VALID;

        if (!(int_mask & TPM_INTF_DATA_AVAIL_INT))
                sts_mask &= ~TPM_STS_DATA_AVAIL;

        if (!(int_mask & TPM_INTF_CMD_READY_INT))
                sts_mask &= ~TPM_STS_COMMAND_READY;

        return sts_mask;
}

static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask,
                unsigned long timeout, wait_queue_head_t *queue,
                bool check_cancel)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        unsigned long stop;
        long rc;
        u8 status;
        bool canceled = false;
        u8 sts_mask;
        int ret = 0;

        /* check current status */
        status = chip->ops->status(chip);
        if ((status & mask) == mask)
                return 0;

        sts_mask = mask & (TPM_STS_VALID | TPM_STS_DATA_AVAIL |
                           TPM_STS_COMMAND_READY);
        /* check what status changes can be handled by irqs */
        sts_mask = tpm_tis_filter_sts_mask(priv->int_mask, sts_mask);

        stop = jiffies + timeout;
        /* process status changes with irq support */
        if (sts_mask) {
                ret = -ETIME;
again:
                timeout = stop - jiffies;
                if ((long)timeout <= 0)
                        return -ETIME;
                rc = wait_event_interruptible_timeout(*queue,
                        wait_for_tpm_stat_cond(chip, sts_mask, check_cancel,
                                               &canceled),
                        timeout);
                if (rc > 0) {
                        if (canceled)
                                return -ECANCELED;
                        ret = 0;
                }
                if (rc == -ERESTARTSYS && freezing(current)) {
                        clear_thread_flag(TIF_SIGPENDING);
                        goto again;
                }
        }

        if (ret)
                return ret;

        mask &= ~sts_mask;
        if (!mask) /* all done */
                return 0;
        /* process status changes without irq support */
        do {
                usleep_range(priv->timeout_min, priv->timeout_max);
                status = chip->ops->status(chip);
                if ((status & mask) == mask)
                        return 0;
        } while (time_before(jiffies, stop));
        return -ETIME;
}

/* Before we attempt to access the TPM we must see that the valid bit is set.
 * The specification says that this bit is 0 at reset and remains 0 until the
 * 'TPM has gone through its self test and initialization and has established
 * correct values in the other bits.'
 */
static int wait_startup(struct tpm_chip *chip, int l)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        unsigned long stop = jiffies + chip->timeout_a;

        do {
                int rc;
                u8 access;

                rc = tpm_tis_read8(priv, TPM_ACCESS(l), &access);
                if (rc < 0)
                        return rc;

                if (access & TPM_ACCESS_VALID)
                        return 0;
                tpm_msleep(TPM_TIMEOUT);
        } while (time_before(jiffies, stop));
        return -1;
}

static bool check_locality(struct tpm_chip *chip, int l)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        int rc;
        u8 access;

        rc = tpm_tis_read8(priv, TPM_ACCESS(l), &access);
        if (rc < 0)
                return false;

        if ((access & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID
                       | TPM_ACCESS_REQUEST_USE)) ==
            (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) {
                priv->locality = l;
                return true;
        }

        return false;
}

static int __tpm_tis_relinquish_locality(struct tpm_tis_data *priv, int l)
{
        tpm_tis_write8(priv, TPM_ACCESS(l), TPM_ACCESS_ACTIVE_LOCALITY);

        return 0;
}

static int tpm_tis_relinquish_locality(struct tpm_chip *chip, int l)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);

        mutex_lock(&priv->locality_count_mutex);
        priv->locality_count--;
        if (priv->locality_count == 0)
                __tpm_tis_relinquish_locality(priv, l);
        mutex_unlock(&priv->locality_count_mutex);

        return 0;
}

static int __tpm_tis_request_locality(struct tpm_chip *chip, int l)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        unsigned long stop, timeout;
        long rc;

        if (check_locality(chip, l))
                return l;

        rc = tpm_tis_write8(priv, TPM_ACCESS(l), TPM_ACCESS_REQUEST_USE);
        if (rc < 0)
                return rc;

        stop = jiffies + chip->timeout_a;

        if (chip->flags & TPM_CHIP_FLAG_IRQ) {
again:
                timeout = stop - jiffies;
                if ((long)timeout <= 0)
                        return -1;
                rc = wait_event_interruptible_timeout(priv->int_queue,
                                                      (check_locality
                                                       (chip, l)),
                                                      timeout);
                if (rc > 0)
                        return l;
                if (rc == -ERESTARTSYS && freezing(current)) {
                        clear_thread_flag(TIF_SIGPENDING);
                        goto again;
                }
        } else {
                /* wait for burstcount */
                do {
                        if (check_locality(chip, l))
                                return l;
                        tpm_msleep(TPM_TIMEOUT);
                } while (time_before(jiffies, stop));
        }
        return -1;
}

static int tpm_tis_request_locality(struct tpm_chip *chip, int l)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        int ret = 0;

        mutex_lock(&priv->locality_count_mutex);
        if (priv->locality_count == 0)
                ret = __tpm_tis_request_locality(chip, l);
        if (!ret)
                priv->locality_count++;
        mutex_unlock(&priv->locality_count_mutex);
        return ret;
}

static u8 tpm_tis_status(struct tpm_chip *chip)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        int rc;
        u8 status;

        rc = tpm_tis_read8(priv, TPM_STS(priv->locality), &status);
        if (rc < 0)
                return 0;

        if (unlikely((status & TPM_STS_READ_ZERO) != 0)) {
                if  (!test_and_set_bit(TPM_TIS_INVALID_STATUS, &priv->flags)) {
                        /*
                         * If this trips, the chances are the read is
                         * returning 0xff because the locality hasn't been
                         * acquired.  Usually because tpm_try_get_ops() hasn't
                         * been called before doing a TPM operation.
                         */
                        dev_err(&chip->dev, "invalid TPM_STS.x 0x%02x, dumping stack for forensics\n",
                                status);

                        /*
                         * Dump stack for forensics, as invalid TPM_STS.x could be
                         * potentially triggered by impaired tpm_try_get_ops().
                         */
                        dump_stack();
                }

                return 0;
        }

        return status;
}

static void tpm_tis_ready(struct tpm_chip *chip)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);

        /* this causes the current command to be aborted */
        tpm_tis_write8(priv, TPM_STS(priv->locality), TPM_STS_COMMAND_READY);
}

static int get_burstcount(struct tpm_chip *chip)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        unsigned long stop;
        int burstcnt, rc;
        u32 value;

        /* wait for burstcount */
        if (chip->flags & TPM_CHIP_FLAG_TPM2)
                stop = jiffies + chip->timeout_a;
        else
                stop = jiffies + chip->timeout_d;
        do {
                rc = tpm_tis_read32(priv, TPM_STS(priv->locality), &value);
                if (rc < 0)
                        return rc;

                burstcnt = (value >> 8) & 0xFFFF;
                if (burstcnt)
                        return burstcnt;
                usleep_range(TPM_TIMEOUT_USECS_MIN, TPM_TIMEOUT_USECS_MAX);
        } while (time_before(jiffies, stop));
        return -EBUSY;
}

static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        int size = 0, burstcnt, rc;

        while (size < count) {
                rc = wait_for_tpm_stat(chip,
                                 TPM_STS_DATA_AVAIL | TPM_STS_VALID,
                                 chip->timeout_c,
                                 &priv->read_queue, true);
                if (rc < 0)
                        return rc;
                burstcnt = get_burstcount(chip);
                if (burstcnt < 0) {
                        dev_err(&chip->dev, "Unable to read burstcount\n");
                        return burstcnt;
                }
                burstcnt = min_t(int, burstcnt, count - size);

                rc = tpm_tis_read_bytes(priv, TPM_DATA_FIFO(priv->locality),
                                        burstcnt, buf + size);
                if (rc < 0)
                        return rc;

                size += burstcnt;
        }
        return size;
}

static int tpm_tis_try_recv(struct tpm_chip *chip, u8 *buf, size_t count)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        int size = 0;
        int status;
        u32 expected;
        int rc;

        size = recv_data(chip, buf, TPM_HEADER_SIZE);
        /* read first 10 bytes, including tag, paramsize, and result */
        if (size < TPM_HEADER_SIZE) {
                dev_err(&chip->dev, "Unable to read header\n");
                goto out;
        }

        expected = be32_to_cpu(*(__be32 *) (buf + 2));
        if (expected > count || expected < TPM_HEADER_SIZE) {
                size = -EIO;
                goto out;
        }

        rc = recv_data(chip, &buf[TPM_HEADER_SIZE],
                       expected - TPM_HEADER_SIZE);
        if (rc < 0) {
                size = rc;
                goto out;
        }
        size += rc;
        if (size < expected) {
                dev_err(&chip->dev, "Unable to read remainder of result\n");
                size = -ETIME;
                goto out;
        }

        if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
                                &priv->int_queue, false) < 0) {
                size = -ETIME;
                goto out;
        }
        status = tpm_tis_status(chip);
        if (status & TPM_STS_DATA_AVAIL) {
                dev_err(&chip->dev, "Error left over data\n");
                size = -EIO;
                goto out;
        }

        rc = tpm_tis_verify_crc(priv, (size_t)size, buf);
        if (rc < 0) {
                dev_err(&chip->dev, "CRC mismatch for response.\n");
                size = rc;
                goto out;
        }

out:
        return size;
}

static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        unsigned int try;
        int rc = 0;

        if (count < TPM_HEADER_SIZE)
                return -EIO;

        for (try = 0; try < TPM_RETRY; try++) {
                rc = tpm_tis_try_recv(chip, buf, count);

                if (rc == -EIO)
                        /* Data transfer errors, indicated by EIO, can be
                         * recovered by rereading the response.
                         */
                        tpm_tis_write8(priv, TPM_STS(priv->locality),
                                       TPM_STS_RESPONSE_RETRY);
                else
                        break;
        }

        tpm_tis_ready(chip);

        return rc;
}

/*
 * If interrupts are used (signaled by an irq set in the vendor structure)
 * tpm.c can skip polling for the data to be available as the interrupt is
 * waited for here
 */
static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        int rc, status, burstcnt;
        size_t count = 0;
        bool itpm = test_bit(TPM_TIS_ITPM_WORKAROUND, &priv->flags);

        status = tpm_tis_status(chip);
        if ((status & TPM_STS_COMMAND_READY) == 0) {
                tpm_tis_ready(chip);
                if (wait_for_tpm_stat
                    (chip, TPM_STS_COMMAND_READY, chip->timeout_b,
                     &priv->int_queue, false) < 0) {
                        rc = -ETIME;
                        goto out_err;
                }
        }

        while (count < len - 1) {
                burstcnt = get_burstcount(chip);
                if (burstcnt < 0) {
                        dev_err(&chip->dev, "Unable to read burstcount\n");
                        rc = burstcnt;
                        goto out_err;
                }
                burstcnt = min_t(int, burstcnt, len - count - 1);
                rc = tpm_tis_write_bytes(priv, TPM_DATA_FIFO(priv->locality),
                                         burstcnt, buf + count);
                if (rc < 0)
                        goto out_err;

                count += burstcnt;

                if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
                                        &priv->int_queue, false) < 0) {
                        if (test_bit(TPM_TIS_STATUS_VALID_RETRY, &priv->flags))
                                rc = -EAGAIN;
                        else
                                rc = -ETIME;
                        goto out_err;
                }
                status = tpm_tis_status(chip);
                if (!itpm && (status & TPM_STS_DATA_EXPECT) == 0) {
                        rc = -EIO;
                        goto out_err;
                }
        }

        /* write last byte */
        rc = tpm_tis_write8(priv, TPM_DATA_FIFO(priv->locality), buf[count]);
        if (rc < 0)
                goto out_err;

        if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
                                &priv->int_queue, false) < 0) {
                if (test_bit(TPM_TIS_STATUS_VALID_RETRY, &priv->flags))
                        rc = -EAGAIN;
                else
                        rc = -ETIME;
                goto out_err;
        }
        status = tpm_tis_status(chip);
        if (!itpm && (status & TPM_STS_DATA_EXPECT) != 0) {
                rc = -EIO;
                goto out_err;
        }

        rc = tpm_tis_verify_crc(priv, len, buf);
        if (rc < 0) {
                dev_err(&chip->dev, "CRC mismatch for command.\n");
                goto out_err;
        }

        return 0;

out_err:
        tpm_tis_ready(chip);
        return rc;
}

static void __tpm_tis_disable_interrupts(struct tpm_chip *chip)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        u32 int_mask = 0;

        tpm_tis_read32(priv, TPM_INT_ENABLE(priv->locality), &int_mask);
        int_mask &= ~TPM_GLOBAL_INT_ENABLE;
        tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality), int_mask);

        chip->flags &= ~TPM_CHIP_FLAG_IRQ;
}

static void tpm_tis_disable_interrupts(struct tpm_chip *chip)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);

        if (priv->irq == 0)
                return;

        __tpm_tis_disable_interrupts(chip);

        devm_free_irq(chip->dev.parent, priv->irq, chip);
        priv->irq = 0;
}

/*
 * If interrupts are used (signaled by an irq set in the vendor structure)
 * tpm.c can skip polling for the data to be available as the interrupt is
 * waited for here
 */
static int tpm_tis_send_main(struct tpm_chip *chip, const u8 *buf, size_t len)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        int rc;
        u32 ordinal;
        unsigned long dur;
        unsigned int try;

        for (try = 0; try < TPM_RETRY; try++) {
                rc = tpm_tis_send_data(chip, buf, len);
                if (rc >= 0)
                        /* Data transfer done successfully */
                        break;
                else if (rc != -EAGAIN && rc != -EIO)
                        /* Data transfer failed, not recoverable */
                        return rc;

                usleep_range(priv->timeout_min, priv->timeout_max);
        }

        /* go and do it */
        rc = tpm_tis_write8(priv, TPM_STS(priv->locality), TPM_STS_GO);
        if (rc < 0)
                goto out_err;

        if (chip->flags & TPM_CHIP_FLAG_IRQ) {
                ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));

                dur = tpm_calc_ordinal_duration(chip, ordinal);
                if (wait_for_tpm_stat
                    (chip, TPM_STS_DATA_AVAIL | TPM_STS_VALID, dur,
                     &priv->read_queue, false) < 0) {
                        rc = -ETIME;
                        goto out_err;
                }
        }
        return 0;
out_err:
        tpm_tis_ready(chip);
        return rc;
}

static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
                        size_t len)
{
        int rc, irq;
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);

        if (!(chip->flags & TPM_CHIP_FLAG_IRQ) ||
             test_bit(TPM_TIS_IRQ_TESTED, &priv->flags))
                return tpm_tis_send_main(chip, buf, len);

        /* Verify receipt of the expected IRQ */
        irq = priv->irq;
        priv->irq = 0;
        chip->flags &= ~TPM_CHIP_FLAG_IRQ;
        rc = tpm_tis_send_main(chip, buf, len);
        priv->irq = irq;
        chip->flags |= TPM_CHIP_FLAG_IRQ;
        if (!test_bit(TPM_TIS_IRQ_TESTED, &priv->flags))
                tpm_msleep(1);
        if (!test_bit(TPM_TIS_IRQ_TESTED, &priv->flags))
                tpm_tis_disable_interrupts(chip);
        set_bit(TPM_TIS_IRQ_TESTED, &priv->flags);
        return rc;
}

struct tis_vendor_durations_override {
        u32 did_vid;
        struct tpm1_version version;
        unsigned long durations[3];
};

static const struct  tis_vendor_durations_override vendor_dur_overrides[] = {
        /* STMicroelectronics 0x104a */
        { 0x0000104a,
          { 1, 2, 8, 28 },
          { (2 * 60 * HZ), (2 * 60 * HZ), (2 * 60 * HZ) } },
};

static void tpm_tis_update_durations(struct tpm_chip *chip,
                                     unsigned long *duration_cap)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        struct tpm1_version *version;
        u32 did_vid;
        int i, rc;
        cap_t cap;

        chip->duration_adjusted = false;

        if (chip->ops->clk_enable != NULL)
                chip->ops->clk_enable(chip, true);

        rc = tpm_tis_read32(priv, TPM_DID_VID(0), &did_vid);
        if (rc < 0) {
                dev_warn(&chip->dev, "%s: failed to read did_vid. %d\n",
                         __func__, rc);
                goto out;
        }

        /* Try to get a TPM version 1.2 or 1.1 TPM_CAP_VERSION_INFO */
        rc = tpm1_getcap(chip, TPM_CAP_VERSION_1_2, &cap,
                         "attempting to determine the 1.2 version",
                         sizeof(cap.version2));
        if (!rc) {
                version = &cap.version2.version;
        } else {
                rc = tpm1_getcap(chip, TPM_CAP_VERSION_1_1, &cap,
                                 "attempting to determine the 1.1 version",
                                 sizeof(cap.version1));

                if (rc)
                        goto out;

                version = &cap.version1;
        }

        for (i = 0; i != ARRAY_SIZE(vendor_dur_overrides); i++) {
                if (vendor_dur_overrides[i].did_vid != did_vid)
                        continue;

                if ((version->major ==
                     vendor_dur_overrides[i].version.major) &&
                    (version->minor ==
                     vendor_dur_overrides[i].version.minor) &&
                    (version->rev_major ==
                     vendor_dur_overrides[i].version.rev_major) &&
                    (version->rev_minor ==
                     vendor_dur_overrides[i].version.rev_minor)) {

                        memcpy(duration_cap,
                               vendor_dur_overrides[i].durations,
                               sizeof(vendor_dur_overrides[i].durations));

                        chip->duration_adjusted = true;
                        goto out;
                }
        }

out:
        if (chip->ops->clk_enable != NULL)
                chip->ops->clk_enable(chip, false);
}

struct tis_vendor_timeout_override {
        u32 did_vid;
        unsigned long timeout_us[4];
};

static const struct tis_vendor_timeout_override vendor_timeout_overrides[] = {
        /* Atmel 3204 */
        { 0x32041114, { (TIS_SHORT_TIMEOUT*1000), (TIS_LONG_TIMEOUT*1000),
                        (TIS_SHORT_TIMEOUT*1000), (TIS_SHORT_TIMEOUT*1000) } },
};

static void tpm_tis_update_timeouts(struct tpm_chip *chip,
                                    unsigned long *timeout_cap)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        int i, rc;
        u32 did_vid;

        chip->timeout_adjusted = false;

        if (chip->ops->clk_enable != NULL)
                chip->ops->clk_enable(chip, true);

        rc = tpm_tis_read32(priv, TPM_DID_VID(0), &did_vid);
        if (rc < 0) {
                dev_warn(&chip->dev, "%s: failed to read did_vid: %d\n",
                         __func__, rc);
                goto out;
        }

        for (i = 0; i != ARRAY_SIZE(vendor_timeout_overrides); i++) {
                if (vendor_timeout_overrides[i].did_vid != did_vid)
                        continue;
                memcpy(timeout_cap, vendor_timeout_overrides[i].timeout_us,
                       sizeof(vendor_timeout_overrides[i].timeout_us));
                chip->timeout_adjusted = true;
        }

out:
        if (chip->ops->clk_enable != NULL)
                chip->ops->clk_enable(chip, false);

        return;
}

/*
 * Early probing for iTPM with STS_DATA_EXPECT flaw.
 * Try sending command without itpm flag set and if that
 * fails, repeat with itpm flag set.
 */
static int probe_itpm(struct tpm_chip *chip)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        int rc = 0;
        static const u8 cmd_getticks[] = {
                0x00, 0xc1, 0x00, 0x00, 0x00, 0x0a,
                0x00, 0x00, 0x00, 0xf1
        };
        size_t len = sizeof(cmd_getticks);
        u16 vendor;

        if (test_bit(TPM_TIS_ITPM_WORKAROUND, &priv->flags))
                return 0;

        rc = tpm_tis_read16(priv, TPM_DID_VID(0), &vendor);
        if (rc < 0)
                return rc;

        /* probe only iTPMS */
        if (vendor != TPM_VID_INTEL)
                return 0;

        if (tpm_tis_request_locality(chip, 0) != 0)
                return -EBUSY;

        rc = tpm_tis_send_data(chip, cmd_getticks, len);
        if (rc == 0)
                goto out;

        tpm_tis_ready(chip);

        set_bit(TPM_TIS_ITPM_WORKAROUND, &priv->flags);

        rc = tpm_tis_send_data(chip, cmd_getticks, len);
        if (rc == 0)
                dev_info(&chip->dev, "Detected an iTPM.\n");
        else {
                clear_bit(TPM_TIS_ITPM_WORKAROUND, &priv->flags);
                rc = -EFAULT;
        }

out:
        tpm_tis_ready(chip);
        tpm_tis_relinquish_locality(chip, priv->locality);

        return rc;
}

static bool tpm_tis_req_canceled(struct tpm_chip *chip, u8 status)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);

        if (!test_bit(TPM_TIS_DEFAULT_CANCELLATION, &priv->flags)) {
                switch (priv->manufacturer_id) {
                case TPM_VID_WINBOND:
                        return ((status == TPM_STS_VALID) ||
                                (status == (TPM_STS_VALID | TPM_STS_COMMAND_READY)));
                case TPM_VID_STM:
                        return (status == (TPM_STS_VALID | TPM_STS_COMMAND_READY));
                default:
                        break;
                }
        }

        return status == TPM_STS_COMMAND_READY;
}

static irqreturn_t tpm_tis_revert_interrupts(struct tpm_chip *chip)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        const char *product;
        const char *vendor;

        dev_warn(&chip->dev, FW_BUG
                 "TPM interrupt storm detected, polling instead\n");

        vendor = dmi_get_system_info(DMI_SYS_VENDOR);
        product = dmi_get_system_info(DMI_PRODUCT_VERSION);

        if (vendor && product) {
                dev_info(&chip->dev,
                        "Consider adding the following entry to tpm_tis_dmi_table:\n");
                dev_info(&chip->dev, "\tDMI_SYS_VENDOR: %s\n", vendor);
                dev_info(&chip->dev, "\tDMI_PRODUCT_VERSION: %s\n", product);
        }

        if (tpm_tis_request_locality(chip, 0) != 0)
                return IRQ_NONE;

        __tpm_tis_disable_interrupts(chip);
        tpm_tis_relinquish_locality(chip, 0);

        schedule_work(&priv->free_irq_work);

        return IRQ_HANDLED;
}

static irqreturn_t tpm_tis_update_unhandled_irqs(struct tpm_chip *chip)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        irqreturn_t irqret = IRQ_HANDLED;

        if (!(chip->flags & TPM_CHIP_FLAG_IRQ))
                return IRQ_HANDLED;

        if (time_after(jiffies, priv->last_unhandled_irq + HZ/10))
                priv->unhandled_irqs = 1;
        else
                priv->unhandled_irqs++;

        priv->last_unhandled_irq = jiffies;

        if (priv->unhandled_irqs > TPM_TIS_MAX_UNHANDLED_IRQS)
                irqret = tpm_tis_revert_interrupts(chip);

        return irqret;
}

static irqreturn_t tis_int_handler(int dummy, void *dev_id)
{
        struct tpm_chip *chip = dev_id;
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        u32 interrupt;
        int rc;

        rc = tpm_tis_read32(priv, TPM_INT_STATUS(priv->locality), &interrupt);
        if (rc < 0)
                goto err;

        if (interrupt == 0)
                goto err;

        set_bit(TPM_TIS_IRQ_TESTED, &priv->flags);
        if (interrupt & TPM_INTF_DATA_AVAIL_INT)
                wake_up_interruptible(&priv->read_queue);

        if (interrupt &
            (TPM_INTF_LOCALITY_CHANGE_INT | TPM_INTF_STS_VALID_INT |
             TPM_INTF_CMD_READY_INT))
                wake_up_interruptible(&priv->int_queue);

        /* Clear interrupts handled with TPM_EOI */
        tpm_tis_request_locality(chip, 0);
        rc = tpm_tis_write32(priv, TPM_INT_STATUS(priv->locality), interrupt);
        tpm_tis_relinquish_locality(chip, 0);
        if (rc < 0)
                goto err;

        tpm_tis_read32(priv, TPM_INT_STATUS(priv->locality), &interrupt);
        return IRQ_HANDLED;

err:
        return tpm_tis_update_unhandled_irqs(chip);
}

static void tpm_tis_gen_interrupt(struct tpm_chip *chip)
{
        const char *desc = "attempting to generate an interrupt";
        u32 cap2;
        cap_t cap;
        int ret;

        chip->flags |= TPM_CHIP_FLAG_IRQ;

        if (chip->flags & TPM_CHIP_FLAG_TPM2)
                ret = tpm2_get_tpm_pt(chip, 0x100, &cap2, desc);
        else
                ret = tpm1_getcap(chip, TPM_CAP_PROP_TIS_TIMEOUT, &cap, desc, 0);

        if (ret)
                chip->flags &= ~TPM_CHIP_FLAG_IRQ;
}

static void tpm_tis_free_irq_func(struct work_struct *work)
{
        struct tpm_tis_data *priv = container_of(work, typeof(*priv), free_irq_work);
        struct tpm_chip *chip = priv->chip;

        devm_free_irq(chip->dev.parent, priv->irq, chip);
        priv->irq = 0;
}

/* Register the IRQ and issue a command that will cause an interrupt. If an
 * irq is seen then leave the chip setup for IRQ operation, otherwise reverse
 * everything and leave in polling mode. Returns 0 on success.
 */
static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask,
                                    int flags, int irq)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        u8 original_int_vec;
        int rc;
        u32 int_status;

        rc = devm_request_threaded_irq(chip->dev.parent, irq, NULL,
                                       tis_int_handler, IRQF_ONESHOT | flags,
                                       dev_name(&chip->dev), chip);
        if (rc) {
                dev_info(&chip->dev, "Unable to request irq: %d for probe\n",
                         irq);
                return -1;
        }
        priv->irq = irq;

        rc = tpm_tis_request_locality(chip, 0);
        if (rc < 0)
                return rc;

        rc = tpm_tis_read8(priv, TPM_INT_VECTOR(priv->locality),
                           &original_int_vec);
        if (rc < 0) {
                tpm_tis_relinquish_locality(chip, priv->locality);
                return rc;
        }

        rc = tpm_tis_write8(priv, TPM_INT_VECTOR(priv->locality), irq);
        if (rc < 0)
                goto restore_irqs;

        rc = tpm_tis_read32(priv, TPM_INT_STATUS(priv->locality), &int_status);
        if (rc < 0)
                goto restore_irqs;

        /* Clear all existing */
        rc = tpm_tis_write32(priv, TPM_INT_STATUS(priv->locality), int_status);
        if (rc < 0)
                goto restore_irqs;
        /* Turn on */
        rc = tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality),
                             intmask | TPM_GLOBAL_INT_ENABLE);
        if (rc < 0)
                goto restore_irqs;

        clear_bit(TPM_TIS_IRQ_TESTED, &priv->flags);

        /* Generate an interrupt by having the core call through to
         * tpm_tis_send
         */
        tpm_tis_gen_interrupt(chip);

restore_irqs:
        /* tpm_tis_send will either confirm the interrupt is working or it
         * will call disable_irq which undoes all of the above.
         */
        if (!(chip->flags & TPM_CHIP_FLAG_IRQ)) {
                tpm_tis_write8(priv, TPM_INT_VECTOR(priv->locality),
                               original_int_vec);
                rc = -1;
        }

        tpm_tis_relinquish_locality(chip, priv->locality);

        return rc;
}

/* Try to find the IRQ the TPM is using. This is for legacy x86 systems that
 * do not have ACPI/etc. We typically expect the interrupt to be declared if
 * present.
 */
static void tpm_tis_probe_irq(struct tpm_chip *chip, u32 intmask)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        u8 original_int_vec;
        int i, rc;

        rc = tpm_tis_read8(priv, TPM_INT_VECTOR(priv->locality),
                           &original_int_vec);
        if (rc < 0)
                return;

        if (!original_int_vec) {
                if (IS_ENABLED(CONFIG_X86))
                        for (i = 3; i <= 15; i++)
                                if (!tpm_tis_probe_irq_single(chip, intmask, 0,
                                                              i))
                                        return;
        } else if (!tpm_tis_probe_irq_single(chip, intmask, 0,
                                             original_int_vec))
                return;
}

void tpm_tis_remove(struct tpm_chip *chip)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        u32 reg = TPM_INT_ENABLE(priv->locality);
        u32 interrupt;
        int rc;

        tpm_tis_clkrun_enable(chip, true);

        rc = tpm_tis_read32(priv, reg, &interrupt);
        if (rc < 0)
                interrupt = 0;

        tpm_tis_write32(priv, reg, ~TPM_GLOBAL_INT_ENABLE & interrupt);
        if (priv->free_irq_work.func)
                flush_work(&priv->free_irq_work);

        tpm_tis_clkrun_enable(chip, false);

        if (priv->ilb_base_addr)
                iounmap(priv->ilb_base_addr);
}
EXPORT_SYMBOL_GPL(tpm_tis_remove);

/**
 * tpm_tis_clkrun_enable() - Keep clkrun protocol disabled for entire duration
 *                           of a single TPM command
 * @chip:       TPM chip to use
 * @value:      1 - Disable CLKRUN protocol, so that clocks are free running
 *              0 - Enable CLKRUN protocol
 * Call this function directly in tpm_tis_remove() in error or driver removal
 * path, since the chip->ops is set to NULL in tpm_chip_unregister().
 */
static void tpm_tis_clkrun_enable(struct tpm_chip *chip, bool value)
{
        struct tpm_tis_data *data = dev_get_drvdata(&chip->dev);
        u32 clkrun_val;

        if (!IS_ENABLED(CONFIG_X86) || !is_bsw() ||
            !data->ilb_base_addr)
                return;

        if (value) {
                data->clkrun_enabled++;
                if (data->clkrun_enabled > 1)
                        return;
                clkrun_val = ioread32(data->ilb_base_addr + LPC_CNTRL_OFFSET);

                /* Disable LPC CLKRUN# */
                clkrun_val &= ~LPC_CLKRUN_EN;
                iowrite32(clkrun_val, data->ilb_base_addr + LPC_CNTRL_OFFSET);

        } else {
                data->clkrun_enabled--;
                if (data->clkrun_enabled)
                        return;

                clkrun_val = ioread32(data->ilb_base_addr + LPC_CNTRL_OFFSET);

                /* Enable LPC CLKRUN# */
                clkrun_val |= LPC_CLKRUN_EN;
                iowrite32(clkrun_val, data->ilb_base_addr + LPC_CNTRL_OFFSET);
        }

#ifdef CONFIG_HAS_IOPORT
        /*
         * Write any random value on port 0x80 which is on LPC, to make
         * sure LPC clock is running before sending any TPM command.
         */
        outb(0xCC, 0x80);
#endif
}

static const struct tpm_class_ops tpm_tis = {
        .flags = TPM_OPS_AUTO_STARTUP,
        .status = tpm_tis_status,
        .recv = tpm_tis_recv,
        .send = tpm_tis_send,
        .cancel = tpm_tis_ready,
        .update_timeouts = tpm_tis_update_timeouts,
        .update_durations = tpm_tis_update_durations,
        .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
        .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
        .req_canceled = tpm_tis_req_canceled,
        .request_locality = tpm_tis_request_locality,
        .relinquish_locality = tpm_tis_relinquish_locality,
        .clk_enable = tpm_tis_clkrun_enable,
};

int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
                      const struct tpm_tis_phy_ops *phy_ops,
                      acpi_handle acpi_dev_handle)
{
        u32 vendor;
        u32 intfcaps;
        u32 intmask;
        u32 clkrun_val;
        u8 rid;
        int rc, probe;
        struct tpm_chip *chip;

        chip = tpmm_chip_alloc(dev, &tpm_tis);
        if (IS_ERR(chip))
                return PTR_ERR(chip);

#ifdef CONFIG_ACPI
        chip->acpi_dev_handle = acpi_dev_handle;
#endif

        chip->hwrng.quality = priv->rng_quality;

        /* Maximum timeouts */
        chip->timeout_a = msecs_to_jiffies(TIS_TIMEOUT_A_MAX);
        chip->timeout_b = msecs_to_jiffies(TIS_TIMEOUT_B_MAX);
        chip->timeout_c = msecs_to_jiffies(TIS_TIMEOUT_C_MAX);
        chip->timeout_d = msecs_to_jiffies(TIS_TIMEOUT_D_MAX);
        priv->chip = chip;
        priv->timeout_min = TPM_TIMEOUT_USECS_MIN;
        priv->timeout_max = TPM_TIMEOUT_USECS_MAX;
        priv->phy_ops = phy_ops;
        priv->locality_count = 0;
        mutex_init(&priv->locality_count_mutex);
        INIT_WORK(&priv->free_irq_work, tpm_tis_free_irq_func);

        dev_set_drvdata(&chip->dev, priv);

        rc = tpm_tis_read32(priv, TPM_DID_VID(0), &vendor);
        if (rc < 0)
                return rc;

        priv->manufacturer_id = vendor;

        if (priv->manufacturer_id == TPM_VID_ATML &&
                !(chip->flags & TPM_CHIP_FLAG_TPM2)) {
                priv->timeout_min = TIS_TIMEOUT_MIN_ATML;
                priv->timeout_max = TIS_TIMEOUT_MAX_ATML;
        }

        if (priv->manufacturer_id == TPM_VID_IFX)
                set_bit(TPM_TIS_STATUS_VALID_RETRY, &priv->flags);

        if (is_bsw()) {
                priv->ilb_base_addr = ioremap(INTEL_LEGACY_BLK_BASE_ADDR,
                                        ILB_REMAP_SIZE);
                if (!priv->ilb_base_addr)
                        return -ENOMEM;

                clkrun_val = ioread32(priv->ilb_base_addr + LPC_CNTRL_OFFSET);
                /* Check if CLKRUN# is already not enabled in the LPC bus */
                if (!(clkrun_val & LPC_CLKRUN_EN)) {
                        iounmap(priv->ilb_base_addr);
                        priv->ilb_base_addr = NULL;
                }
        }

        if (chip->ops->clk_enable != NULL)
                chip->ops->clk_enable(chip, true);

        if (wait_startup(chip, 0) != 0) {
                rc = -ENODEV;
                goto out_err;
        }

        /* Take control of the TPM's interrupt hardware and shut it off */
        rc = tpm_tis_read32(priv, TPM_INT_ENABLE(priv->locality), &intmask);
        if (rc < 0)
                goto out_err;

        /* Figure out the capabilities */
        rc = tpm_tis_read32(priv, TPM_INTF_CAPS(priv->locality), &intfcaps);
        if (rc < 0)
                goto out_err;

        dev_dbg(dev, "TPM interface capabilities (0x%x):\n",
                intfcaps);
        if (intfcaps & TPM_INTF_BURST_COUNT_STATIC)
                dev_dbg(dev, "\tBurst Count Static\n");
        if (intfcaps & TPM_INTF_CMD_READY_INT) {
                intmask |= TPM_INTF_CMD_READY_INT;
                dev_dbg(dev, "\tCommand Ready Int Support\n");
        }
        if (intfcaps & TPM_INTF_INT_EDGE_FALLING)
                dev_dbg(dev, "\tInterrupt Edge Falling\n");
        if (intfcaps & TPM_INTF_INT_EDGE_RISING)
                dev_dbg(dev, "\tInterrupt Edge Rising\n");
        if (intfcaps & TPM_INTF_INT_LEVEL_LOW)
                dev_dbg(dev, "\tInterrupt Level Low\n");
        if (intfcaps & TPM_INTF_INT_LEVEL_HIGH)
                dev_dbg(dev, "\tInterrupt Level High\n");
        if (intfcaps & TPM_INTF_LOCALITY_CHANGE_INT) {
                intmask |= TPM_INTF_LOCALITY_CHANGE_INT;
                dev_dbg(dev, "\tLocality Change Int Support\n");
        }
        if (intfcaps & TPM_INTF_STS_VALID_INT) {
                intmask |= TPM_INTF_STS_VALID_INT;
                dev_dbg(dev, "\tSts Valid Int Support\n");
        }
        if (intfcaps & TPM_INTF_DATA_AVAIL_INT) {
                intmask |= TPM_INTF_DATA_AVAIL_INT;
                dev_dbg(dev, "\tData Avail Int Support\n");
        }

        intmask &= ~TPM_GLOBAL_INT_ENABLE;

        rc = tpm_tis_request_locality(chip, 0);
        if (rc < 0) {
                rc = -ENODEV;
                goto out_err;
        }

        tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality), intmask);
        tpm_tis_relinquish_locality(chip, 0);

        rc = tpm_chip_start(chip);
        if (rc)
                goto out_err;
        rc = tpm2_probe(chip);
        tpm_chip_stop(chip);
        if (rc)
                goto out_err;

        rc = tpm_tis_read8(priv, TPM_RID(0), &rid);
        if (rc < 0)
                goto out_err;

        dev_info(dev, "%s TPM (device-id 0x%X, rev-id %d)\n",
                 (chip->flags & TPM_CHIP_FLAG_TPM2) ? "2.0" : "1.2",
                 vendor >> 16, rid);

        probe = probe_itpm(chip);
        if (probe < 0) {
                rc = -ENODEV;
                goto out_err;
        }

        /* INTERRUPT Setup */
        init_waitqueue_head(&priv->read_queue);
        init_waitqueue_head(&priv->int_queue);

        rc = tpm_chip_bootstrap(chip);
        if (rc)
                goto out_err;

        if (irq != -1) {
                /*
                 * Before doing irq testing issue a command to the TPM in polling mode
                 * to make sure it works. May as well use that command to set the
                 * proper timeouts for the driver.
                 */

                rc = tpm_tis_request_locality(chip, 0);
                if (rc < 0)
                        goto out_err;

                rc = tpm_get_timeouts(chip);

                tpm_tis_relinquish_locality(chip, 0);

                if (rc) {
                        dev_err(dev, "Could not get TPM timeouts and durations\n");
                        rc = -ENODEV;
                        goto out_err;
                }

                if (irq)
                        tpm_tis_probe_irq_single(chip, intmask, IRQF_SHARED,
                                                 irq);
                else
                        tpm_tis_probe_irq(chip, intmask);

                if (chip->flags & TPM_CHIP_FLAG_IRQ) {
                        priv->int_mask = intmask;
                } else {
                        dev_err(&chip->dev, FW_BUG
                                        "TPM interrupt not working, polling instead\n");

                        rc = tpm_tis_request_locality(chip, 0);
                        if (rc < 0)
                                goto out_err;
                        tpm_tis_disable_interrupts(chip);
                        tpm_tis_relinquish_locality(chip, 0);
                }
        }

        rc = tpm_chip_register(chip);
        if (rc)
                goto out_err;

        if (chip->ops->clk_enable != NULL)
                chip->ops->clk_enable(chip, false);

        return 0;
out_err:
        if (chip->ops->clk_enable != NULL)
                chip->ops->clk_enable(chip, false);

        tpm_tis_remove(chip);

        return rc;
}
EXPORT_SYMBOL_GPL(tpm_tis_core_init);

#ifdef CONFIG_PM_SLEEP
static void tpm_tis_reenable_interrupts(struct tpm_chip *chip)
{
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
        u32 intmask;
        int rc;

        /*
         * Re-enable interrupts that device may have lost or BIOS/firmware may
         * have disabled.
         */
        rc = tpm_tis_write8(priv, TPM_INT_VECTOR(priv->locality), priv->irq);
        if (rc < 0) {
                dev_err(&chip->dev, "Setting IRQ failed.\n");
                return;
        }

        intmask = priv->int_mask | TPM_GLOBAL_INT_ENABLE;
        rc = tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality), intmask);
        if (rc < 0)
                dev_err(&chip->dev, "Enabling interrupts failed.\n");
}

int tpm_tis_resume(struct device *dev)
{
        struct tpm_chip *chip = dev_get_drvdata(dev);
        int ret;

        ret = tpm_chip_start(chip);
        if (ret)
                return ret;

        if (chip->flags & TPM_CHIP_FLAG_IRQ)
                tpm_tis_reenable_interrupts(chip);

        /*
         * TPM 1.2 requires self-test on resume. This function actually returns
         * an error code but for unknown reason it isn't handled.
         */
        if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
                tpm1_do_selftest(chip);

        tpm_chip_stop(chip);

        ret = tpm_pm_resume(dev);
        if (ret)
                return ret;

        return 0;
}
EXPORT_SYMBOL_GPL(tpm_tis_resume);
#endif

MODULE_AUTHOR("Leendert van Doorn <leendert@watson.ibm.com>");
MODULE_DESCRIPTION("TPM Driver");
MODULE_VERSION("2.0");
MODULE_LICENSE("GPL");