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/*

 * tpm_tis.c - QEMU's TPM TIS interface emulator

 *

 * Copyright (C) 2006,2010-2013 IBM Corporation

 *

 * Authors:

 *  Stefan Berger <stefanb@us.ibm.com>

 *  David Safford <safford@us.ibm.com>

 *

 * Xen 4 support: Andrease Niederl <andreas.niederl@iaik.tugraz.at>

 *

 * This work is licensed under the terms of the GNU GPL, version 2 or later.

 * See the COPYING file in the top-level directory.

 *

 * Implementation of the TIS interface according to specs found at

 * http://www.trustedcomputinggroup.org. This implementation currently

 * supports version 1.21, revision 1.0.

 * In the developers menu choose the PC Client section then find the TIS

 * specification.

 */

#include "sysemu/tpm_backend.h"

#include "tpm_int.h"

#include "block/block.h"

#include "exec/address-spaces.h"

#include "hw/hw.h"

#include "hw/i386/pc.h"

#include "hw/pci/pci_ids.h"

#include "tpm_tis.h"

#include "qemu-common.h"

/*#define DEBUG_TIS */

#ifdef DEBUG_TIS

#define DPRINTF(fmt, ...) \

    do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)

#else

#define DPRINTF(fmt, ...) \

    do { } while (0)

#endif

/* whether the STS interrupt is supported */

#define RAISE_STS_IRQ

/* tis registers */

#define TPM_TIS_REG_ACCESS                0x00

#define TPM_TIS_REG_INT_ENABLE            0x08

#define TPM_TIS_REG_INT_VECTOR            0x0c

#define TPM_TIS_REG_INT_STATUS            0x10

#define TPM_TIS_REG_INTF_CAPABILITY       0x14

#define TPM_TIS_REG_STS                   0x18

#define TPM_TIS_REG_DATA_FIFO             0x24

#define TPM_TIS_REG_DID_VID               0xf00

#define TPM_TIS_REG_RID                   0xf04

/* vendor-specific registers */

#define TPM_TIS_REG_DEBUG                 0xf90

#define TPM_TIS_STS_VALID                 (1 << 7)

#define TPM_TIS_STS_COMMAND_READY         (1 << 6)

#define TPM_TIS_STS_TPM_GO                (1 << 5)

#define TPM_TIS_STS_DATA_AVAILABLE        (1 << 4)

#define TPM_TIS_STS_EXPECT                (1 << 3)

#define TPM_TIS_STS_RESPONSE_RETRY        (1 << 1)

#define TPM_TIS_BURST_COUNT_SHIFT         8

#define TPM_TIS_BURST_COUNT(X) \

    ((X) << TPM_TIS_BURST_COUNT_SHIFT)

#define TPM_TIS_ACCESS_TPM_REG_VALID_STS  (1 << 7)

#define TPM_TIS_ACCESS_ACTIVE_LOCALITY    (1 << 5)

#define TPM_TIS_ACCESS_BEEN_SEIZED        (1 << 4)

#define TPM_TIS_ACCESS_SEIZE              (1 << 3)

#define TPM_TIS_ACCESS_PENDING_REQUEST    (1 << 2)

#define TPM_TIS_ACCESS_REQUEST_USE        (1 << 1)

#define TPM_TIS_ACCESS_TPM_ESTABLISHMENT  (1 << 0)

#define TPM_TIS_INT_ENABLED               (1 << 31)

#define TPM_TIS_INT_DATA_AVAILABLE        (1 << 0)

#define TPM_TIS_INT_STS_VALID             (1 << 1)

#define TPM_TIS_INT_LOCALITY_CHANGED      (1 << 2)

#define TPM_TIS_INT_COMMAND_READY         (1 << 7)

#define TPM_TIS_INT_POLARITY_MASK         (3 << 3)

#define TPM_TIS_INT_POLARITY_LOW_LEVEL    (1 << 3)

#ifndef RAISE_STS_IRQ

#define TPM_TIS_INTERRUPTS_SUPPORTED (TPM_TIS_INT_LOCALITY_CHANGED | \

                                      TPM_TIS_INT_DATA_AVAILABLE   | \

                                      TPM_TIS_INT_COMMAND_READY)

#else

#define TPM_TIS_INTERRUPTS_SUPPORTED (TPM_TIS_INT_LOCALITY_CHANGED | \

                                      TPM_TIS_INT_DATA_AVAILABLE   | \

                                      TPM_TIS_INT_STS_VALID | \

                                      TPM_TIS_INT_COMMAND_READY)

#endif

#define TPM_TIS_CAP_INTERRUPT_LOW_LEVEL  (1 << 4) /* support is mandatory */

#define TPM_TIS_CAPABILITIES_SUPPORTED   (TPM_TIS_CAP_INTERRUPT_LOW_LEVEL | \

                                          TPM_TIS_INTERRUPTS_SUPPORTED)

#define TPM_TIS_TPM_DID       0x0001

#define TPM_TIS_TPM_VID       PCI_VENDOR_ID_IBM

#define TPM_TIS_TPM_RID       0x0001

#define TPM_TIS_NO_DATA_BYTE  0xff

/* local prototypes */

static uint64_t tpm_tis_mmio_read(void *opaque, hwaddr addr,

                                  unsigned size);

/* utility functions */

static uint8_t tpm_tis_locality_from_addr(hwaddr addr)

{

    return (uint8_t)((addr >> TPM_TIS_LOCALITY_SHIFT) & 0x7);

}

static uint32_t tpm_tis_get_size_from_buffer(const TPMSizedBuffer *sb)

{

    return be32_to_cpu(*(uint32_t *)&sb->buffer[2]);

}

static void tpm_tis_show_buffer(const TPMSizedBuffer *sb, const char *string)

{

#ifdef DEBUG_TIS

    uint32_t len, i;

    len = tpm_tis_get_size_from_buffer(sb);

    DPRINTF("tpm_tis: %s length = %d\n", string, len);

    for (i = 0; i < len; i++) {

        if (i && !(i % 16)) {

            DPRINTF("\n");

        }

        DPRINTF("%.2X ", sb->buffer[i]);

    }

    DPRINTF("\n");

#endif

}

/*

 * Send a request to the TPM.

 */

static void tpm_tis_tpm_send(TPMState *s, uint8_t locty)

{

    TPMTISEmuState *tis = &s->s.tis;

    tpm_tis_show_buffer(&tis->loc[locty].w_buffer, "tpm_tis: To TPM");

    s->locty_number = locty;

    s->locty_data = &tis->loc[locty];

    /*

     * w_offset serves as length indicator for length of data;

     * it's reset when the response comes back

     */

    tis->loc[locty].state = TPM_TIS_STATE_EXECUTION;

    tpm_backend_deliver_request(s->be_driver);

}

/* raise an interrupt if allowed */

static void tpm_tis_raise_irq(TPMState *s, uint8_t locty, uint32_t irqmask)

{

    TPMTISEmuState *tis = &s->s.tis;

    if (!TPM_TIS_IS_VALID_LOCTY(locty)) {

        return;

    }

    if ((tis->loc[locty].inte & TPM_TIS_INT_ENABLED) &&

        (tis->loc[locty].inte & irqmask)) {

        DPRINTF("tpm_tis: Raising IRQ for flag %08x\n", irqmask);

        qemu_irq_raise(s->s.tis.irq);

        tis->loc[locty].ints |= irqmask;

    }

}

static uint32_t tpm_tis_check_request_use_except(TPMState *s, uint8_t locty)

{

    uint8_t l;

    for (l = 0; l < TPM_TIS_NUM_LOCALITIES; l++) {

        if (l == locty) {

            continue;

        }

        if ((s->s.tis.loc[l].access & TPM_TIS_ACCESS_REQUEST_USE)) {

            return 1;

        }

    }

    return 0;

}

static void tpm_tis_new_active_locality(TPMState *s, uint8_t new_active_locty)

{

    TPMTISEmuState *tis = &s->s.tis;

    bool change = (s->s.tis.active_locty != new_active_locty);

    bool is_seize;

    uint8_t mask;

    if (change && TPM_TIS_IS_VALID_LOCTY(s->s.tis.active_locty)) {

        is_seize = TPM_TIS_IS_VALID_LOCTY(new_active_locty) &&

                   tis->loc[new_active_locty].access & TPM_TIS_ACCESS_SEIZE;

        if (is_seize) {

            mask = ~(TPM_TIS_ACCESS_ACTIVE_LOCALITY);

        } else {

            mask = ~(TPM_TIS_ACCESS_ACTIVE_LOCALITY|

                     TPM_TIS_ACCESS_REQUEST_USE);

        }

        /* reset flags on the old active locality */

        tis->loc[s->s.tis.active_locty].access &= mask;

        if (is_seize) {

            tis->loc[tis->active_locty].access |= TPM_TIS_ACCESS_BEEN_SEIZED;

        }

    }

    tis->active_locty = new_active_locty;

    DPRINTF("tpm_tis: Active locality is now %d\n", s->s.tis.active_locty);

    if (TPM_TIS_IS_VALID_LOCTY(new_active_locty)) {

        /* set flags on the new active locality */

        tis->loc[new_active_locty].access |= TPM_TIS_ACCESS_ACTIVE_LOCALITY;

        tis->loc[new_active_locty].access &= ~(TPM_TIS_ACCESS_REQUEST_USE |

                                               TPM_TIS_ACCESS_SEIZE);

    }

    if (change) {

        tpm_tis_raise_irq(s, tis->active_locty, TPM_TIS_INT_LOCALITY_CHANGED);

    }

}

/* abort -- this function switches the locality */

static void tpm_tis_abort(TPMState *s, uint8_t locty)

{

    TPMTISEmuState *tis = &s->s.tis;

    tis->loc[locty].r_offset = 0;

    tis->loc[locty].w_offset = 0;

    DPRINTF("tpm_tis: tis_abort: new active locality is %d\n", tis->next_locty);

    /*

     * Need to react differently depending on who's aborting now and

     * which locality will become active afterwards.

     */

    if (tis->aborting_locty == tis->next_locty) {

        tis->loc[tis->aborting_locty].state = TPM_TIS_STATE_READY;

        tis->loc[tis->aborting_locty].sts = TPM_TIS_STS_COMMAND_READY;

        tpm_tis_raise_irq(s, tis->aborting_locty, TPM_TIS_INT_COMMAND_READY);

    }

    /* locality after abort is another one than the current one */

    tpm_tis_new_active_locality(s, tis->next_locty);

    tis->next_locty = TPM_TIS_NO_LOCALITY;

    /* nobody's aborting a command anymore */

    tis->aborting_locty = TPM_TIS_NO_LOCALITY;

}

/* prepare aborting current command */

static void tpm_tis_prep_abort(TPMState *s, uint8_t locty, uint8_t newlocty)

{

    TPMTISEmuState *tis = &s->s.tis;

    uint8_t busy_locty;

    tis->aborting_locty = locty;

    tis->next_locty = newlocty;  /* locality after successful abort */

    /*

     * only abort a command using an interrupt if currently executing

     * a command AND if there's a valid connection to the vTPM.

     */

    for (busy_locty = 0; busy_locty < TPM_TIS_NUM_LOCALITIES; busy_locty++) {

        if (tis->loc[busy_locty].state == TPM_TIS_STATE_EXECUTION) {

            /*

             * request the backend to cancel. Some backends may not

             * support it

             */

            tpm_backend_cancel_cmd(s->be_driver);

            return;

        }

    }

    tpm_tis_abort(s, locty);

}

static void tpm_tis_receive_bh(void *opaque)

{

    TPMState *s = opaque;

    TPMTISEmuState *tis = &s->s.tis;

    uint8_t locty = s->locty_number;

    tis->loc[locty].sts = TPM_TIS_STS_VALID | TPM_TIS_STS_DATA_AVAILABLE;

    tis->loc[locty].state = TPM_TIS_STATE_COMPLETION;

    tis->loc[locty].r_offset = 0;

    tis->loc[locty].w_offset = 0;

    if (TPM_TIS_IS_VALID_LOCTY(tis->next_locty)) {

        tpm_tis_abort(s, locty);

    }

#ifndef RAISE_STS_IRQ

    tpm_tis_raise_irq(s, locty, TPM_TIS_INT_DATA_AVAILABLE);

#else

    tpm_tis_raise_irq(s, locty,

                      TPM_TIS_INT_DATA_AVAILABLE | TPM_TIS_INT_STS_VALID);

#endif

}

/*

 * Callback from the TPM to indicate that the response was received.

 */

static void tpm_tis_receive_cb(TPMState *s, uint8_t locty)

{

    TPMTISEmuState *tis = &s->s.tis;

    assert(s->locty_number == locty);

    qemu_bh_schedule(tis->bh);

}

/*

 * Read a byte of response data

 */

static uint32_t tpm_tis_data_read(TPMState *s, uint8_t locty)

{

    TPMTISEmuState *tis = &s->s.tis;

    uint32_t ret = TPM_TIS_NO_DATA_BYTE;

    uint16_t len;

    if ((tis->loc[locty].sts & TPM_TIS_STS_DATA_AVAILABLE)) {

        len = tpm_tis_get_size_from_buffer(&tis->loc[locty].r_buffer);

        ret = tis->loc[locty].r_buffer.buffer[tis->loc[locty].r_offset++];

        if (tis->loc[locty].r_offset >= len) {

            /* got last byte */

            tis->loc[locty].sts = TPM_TIS_STS_VALID;

#ifdef RAISE_STS_IRQ

            tpm_tis_raise_irq(s, locty, TPM_TIS_INT_STS_VALID);

#endif

        }

        DPRINTF("tpm_tis: tpm_tis_data_read byte 0x%02x   [%d]\n",

                ret, tis->loc[locty].r_offset-1);

    }

    return ret;

}

#ifdef DEBUG_TIS

static void tpm_tis_dump_state(void *opaque, hwaddr addr)

{

    static const unsigned regs[] = {

        TPM_TIS_REG_ACCESS,

        TPM_TIS_REG_INT_ENABLE,

        TPM_TIS_REG_INT_VECTOR,

        TPM_TIS_REG_INT_STATUS,

        TPM_TIS_REG_INTF_CAPABILITY,

        TPM_TIS_REG_STS,

        TPM_TIS_REG_DID_VID,

        TPM_TIS_REG_RID,

        0xfff};

    int idx;

    uint8_t locty = tpm_tis_locality_from_addr(addr);

    hwaddr base = addr & ~0xfff;

    TPMState *s = opaque;

    TPMTISEmuState *tis = &s->s.tis;

    DPRINTF("tpm_tis: active locality      : %d\n"

            "tpm_tis: state of locality %d : %d\n"

            "tpm_tis: register dump:\n",

            tis->active_locty,

            locty, tis->loc[locty].state);

    for (idx = 0; regs[idx] != 0xfff; idx++) {

        DPRINTF("tpm_tis: 0x%04x : 0x%08x\n", regs[idx],

                (uint32_t)tpm_tis_mmio_read(opaque, base + regs[idx], 4));

    }

    DPRINTF("tpm_tis: read offset   : %d\n"

            "tpm_tis: result buffer : ",

            tis->loc[locty].r_offset);

    for (idx = 0;

         idx < tpm_tis_get_size_from_buffer(&tis->loc[locty].r_buffer);

         idx++) {

        DPRINTF("%c%02x%s",

                tis->loc[locty].r_offset == idx ? '>' : ' ',

                tis->loc[locty].r_buffer.buffer[idx],

                ((idx & 0xf) == 0xf) ? "\ntpm_tis:                 " : "");

    }

    DPRINTF("\n"

            "tpm_tis: write offset  : %d\n"

            "tpm_tis: request buffer: ",

            tis->loc[locty].w_offset);

    for (idx = 0;

         idx < tpm_tis_get_size_from_buffer(&tis->loc[locty].w_buffer);

         idx++) {

        DPRINTF("%c%02x%s",

                tis->loc[locty].w_offset == idx ? '>' : ' ',

                tis->loc[locty].w_buffer.buffer[idx],

                ((idx & 0xf) == 0xf) ? "\ntpm_tis:                 " : "");

    }

    DPRINTF("\n");

}

#endif

/*

 * Read a register of the TIS interface

 * See specs pages 33-63 for description of the registers

 */

static uint64_t tpm_tis_mmio_read(void *opaque, hwaddr addr,

                                  unsigned size)

{

    TPMState *s = opaque;

    TPMTISEmuState *tis = &s->s.tis;

    uint16_t offset = addr & 0xffc;

    uint8_t shift = (addr & 0x3) * 8;

    uint32_t val = 0xffffffff;

    uint8_t locty = tpm_tis_locality_from_addr(addr);

    uint32_t avail;

    if (tpm_backend_had_startup_error(s->be_driver)) {

        return val;

    }

    switch (offset) {

    case TPM_TIS_REG_ACCESS:

        /* never show the SEIZE flag even though we use it internally */

        val = tis->loc[locty].access & ~TPM_TIS_ACCESS_SEIZE;

        /* the pending flag is always calculated */

        if (tpm_tis_check_request_use_except(s, locty)) {

            val |= TPM_TIS_ACCESS_PENDING_REQUEST;

        }

        val |= !tpm_backend_get_tpm_established_flag(s->be_driver);

        break;

    case TPM_TIS_REG_INT_ENABLE:

        val = tis->loc[locty].inte;

        break;

    case TPM_TIS_REG_INT_VECTOR:

        val = tis->irq_num;

        break;

    case TPM_TIS_REG_INT_STATUS:

        val = tis->loc[locty].ints;

        break;

    case TPM_TIS_REG_INTF_CAPABILITY:

        val = TPM_TIS_CAPABILITIES_SUPPORTED;

        break;

    case TPM_TIS_REG_STS:

        if (tis->active_locty == locty) {

            if ((tis->loc[locty].sts & TPM_TIS_STS_DATA_AVAILABLE)) {

                val = TPM_TIS_BURST_COUNT(

                       tpm_tis_get_size_from_buffer(&tis->loc[locty].r_buffer)

                       - tis->loc[locty].r_offset) | tis->loc[locty].sts;

            } else {

                avail = tis->loc[locty].w_buffer.size

                        - tis->loc[locty].w_offset;

                /*

                 * byte-sized reads should not return 0x00 for 0x100

                 * available bytes.

                 */

                if (size == 1 && avail > 0xff) {

                    avail = 0xff;

                }

                val = TPM_TIS_BURST_COUNT(avail) | tis->loc[locty].sts;

            }

        }

        break;

    case TPM_TIS_REG_DATA_FIFO:

        if (tis->active_locty == locty) {

            switch (tis->loc[locty].state) {

            case TPM_TIS_STATE_COMPLETION:

                val = tpm_tis_data_read(s, locty);

                break;

            default:

                val = TPM_TIS_NO_DATA_BYTE;

                break;

            }

        }

        break;

    case TPM_TIS_REG_DID_VID:

        val = (TPM_TIS_TPM_DID << 16) | TPM_TIS_TPM_VID;

        break;

    case TPM_TIS_REG_RID:

        val = TPM_TIS_TPM_RID;

        break;

#ifdef DEBUG_TIS

    case TPM_TIS_REG_DEBUG:

        tpm_tis_dump_state(opaque, addr);

        break;

#endif

    }

    if (shift) {

        val >>= shift;

    }

    DPRINTF("tpm_tis:  read.%u(%08x) = %08x\n", size, (int)addr, (uint32_t)val);

    return val;

}

/*

 * Write a value to a register of the TIS interface

 * See specs pages 33-63 for description of the registers

 */

static void tpm_tis_mmio_write_intern(void *opaque, hwaddr addr,

                                      uint64_t val, unsigned size,

                                      bool hw_access)

{

    TPMState *s = opaque;

    TPMTISEmuState *tis = &s->s.tis;

    uint16_t off = addr & 0xfff;

    uint8_t locty = tpm_tis_locality_from_addr(addr);

    uint8_t active_locty, l;

    int c, set_new_locty = 1;

    uint16_t len;

    DPRINTF("tpm_tis: write.%u(%08x) = %08x\n", size, (int)addr, (uint32_t)val);

    if (locty == 4 && !hw_access) {

        DPRINTF("tpm_tis: Access to locality 4 only allowed from hardware\n");

        return;

    }

    if (tpm_backend_had_startup_error(s->be_driver)) {

        return;

    }

    switch (off) {

    case TPM_TIS_REG_ACCESS:

        if ((val & TPM_TIS_ACCESS_SEIZE)) {

            val &= ~(TPM_TIS_ACCESS_REQUEST_USE |

                     TPM_TIS_ACCESS_ACTIVE_LOCALITY);

        }

        active_locty = tis->active_locty;

        if ((val & TPM_TIS_ACCESS_ACTIVE_LOCALITY)) {

            /* give up locality if currently owned */

            if (tis->active_locty == locty) {

                DPRINTF("tpm_tis: Releasing locality %d\n", locty);

                uint8_t newlocty = TPM_TIS_NO_LOCALITY;

                /* anybody wants the locality ? */

                for (c = TPM_TIS_NUM_LOCALITIES - 1; c >= 0; c--) {

                    if ((tis->loc[c].access & TPM_TIS_ACCESS_REQUEST_USE)) {

                        DPRINTF("tpm_tis: Locality %d requests use.\n", c);

                        newlocty = c;

                        break;

                    }

                }

                DPRINTF("tpm_tis: TPM_TIS_ACCESS_ACTIVE_LOCALITY: "

                        "Next active locality: %d\n",

                        newlocty);

                if (TPM_TIS_IS_VALID_LOCTY(newlocty)) {

                    set_new_locty = 0;

                    tpm_tis_prep_abort(s, locty, newlocty);

                } else {

                    active_locty = TPM_TIS_NO_LOCALITY;

                }

            } else {

                /* not currently the owner; clear a pending request */

                tis->loc[locty].access &= ~TPM_TIS_ACCESS_REQUEST_USE;

            }

        }

        if ((val & TPM_TIS_ACCESS_BEEN_SEIZED)) {

            tis->loc[locty].access &= ~TPM_TIS_ACCESS_BEEN_SEIZED;

        }

        if ((val & TPM_TIS_ACCESS_SEIZE)) {

            /*

             * allow seize if a locality is active and the requesting

             * locality is higher than the one that's active

             * OR

             * allow seize for requesting locality if no locality is

             * active

             */

            while ((TPM_TIS_IS_VALID_LOCTY(tis->active_locty) &&

                    locty > tis->active_locty) ||

                    !TPM_TIS_IS_VALID_LOCTY(tis->active_locty)) {

                bool higher_seize = FALSE;

                /* already a pending SEIZE ? */

                if ((tis->loc[locty].access & TPM_TIS_ACCESS_SEIZE)) {

                    break;

                }

                /* check for ongoing seize by a higher locality */

                for (l = locty + 1; l < TPM_TIS_NUM_LOCALITIES; l++) {

                    if ((tis->loc[l].access & TPM_TIS_ACCESS_SEIZE)) {

                        higher_seize = TRUE;

                        break;

                    }

                }

                if (higher_seize) {

                    break;

                }

                /* cancel any seize by a lower locality */

                for (l = 0; l < locty - 1; l++) {

                    tis->loc[l].access &= ~TPM_TIS_ACCESS_SEIZE;

                }

                tis->loc[locty].access |= TPM_TIS_ACCESS_SEIZE;

                DPRINTF("tpm_tis: TPM_TIS_ACCESS_SEIZE: "

                        "Locality %d seized from locality %d\n",

                        locty, tis->active_locty);

                DPRINTF("tpm_tis: TPM_TIS_ACCESS_SEIZE: Initiating abort.\n");

                set_new_locty = 0;

                tpm_tis_prep_abort(s, tis->active_locty, locty);

                break;

            }

        }

        if ((val & TPM_TIS_ACCESS_REQUEST_USE)) {

            if (tis->active_locty != locty) {

                if (TPM_TIS_IS_VALID_LOCTY(tis->active_locty)) {

                    tis->loc[locty].access |= TPM_TIS_ACCESS_REQUEST_USE;

                } else {

                    /* no locality active -> make this one active now */

                    active_locty = locty;

                }

            }

        }

        if (set_new_locty) {

            tpm_tis_new_active_locality(s, active_locty);

        }

        break;

    case TPM_TIS_REG_INT_ENABLE:

        if (tis->active_locty != locty) {

            break;

        }

        tis->loc[locty].inte = (val & (TPM_TIS_INT_ENABLED |

                                       TPM_TIS_INT_POLARITY_MASK |

                                       TPM_TIS_INTERRUPTS_SUPPORTED));

        break;

    case TPM_TIS_REG_INT_VECTOR:

        /* hard wired -- ignore */

        break;

    case TPM_TIS_REG_INT_STATUS:

        if (tis->active_locty != locty) {

            break;

        }

        /* clearing of interrupt flags */

        if (((val & TPM_TIS_INTERRUPTS_SUPPORTED)) &&

            (tis->loc[locty].ints & TPM_TIS_INTERRUPTS_SUPPORTED)) {

            tis->loc[locty].ints &= ~val;

            if (tis->loc[locty].ints == 0) {

                qemu_irq_lower(tis->irq);

                DPRINTF("tpm_tis: Lowering IRQ\n");

            }

        }

        tis->loc[locty].ints &= ~(val & TPM_TIS_INTERRUPTS_SUPPORTED);

        break;

    case TPM_TIS_REG_STS:

        if (tis->active_locty != locty) {

            break;

        }

        val &= (TPM_TIS_STS_COMMAND_READY | TPM_TIS_STS_TPM_GO |

                TPM_TIS_STS_RESPONSE_RETRY);

        if (val == TPM_TIS_STS_COMMAND_READY) {

            switch (tis->loc[locty].state) {

            case TPM_TIS_STATE_READY:

                tis->loc[locty].w_offset = 0;

                tis->loc[locty].r_offset = 0;

            break;

            case TPM_TIS_STATE_IDLE:

                tis->loc[locty].sts = TPM_TIS_STS_COMMAND_READY;

                tis->loc[locty].state = TPM_TIS_STATE_READY;

                tpm_tis_raise_irq(s, locty, TPM_TIS_INT_COMMAND_READY);

            break;

            case TPM_TIS_STATE_EXECUTION:

            case TPM_TIS_STATE_RECEPTION:

                /* abort currently running command */

                DPRINTF("tpm_tis: %s: Initiating abort.\n",

                        __func__);

                tpm_tis_prep_abort(s, locty, locty);

            break;

            case TPM_TIS_STATE_COMPLETION:

                tis->loc[locty].w_offset = 0;

                tis->loc[locty].r_offset = 0;

                /* shortcut to ready state with C/R set */

                tis->loc[locty].state = TPM_TIS_STATE_READY;

                if (!(tis->loc[locty].sts & TPM_TIS_STS_COMMAND_READY)) {

                    tis->loc[locty].sts   = TPM_TIS_STS_COMMAND_READY;

                    tpm_tis_raise_irq(s, locty, TPM_TIS_INT_COMMAND_READY);

                }

                tis->loc[locty].sts &= ~(TPM_TIS_STS_DATA_AVAILABLE);

            break;

            }

        } else if (val == TPM_TIS_STS_TPM_GO) {

            switch (tis->loc[locty].state) {

            case TPM_TIS_STATE_RECEPTION:

                if ((tis->loc[locty].sts & TPM_TIS_STS_EXPECT) == 0) {

                    tpm_tis_tpm_send(s, locty);

                }

                break;

            default:

                /* ignore */

                break;

            }

        } else if (val == TPM_TIS_STS_RESPONSE_RETRY) {

            switch (tis->loc[locty].state) {

            case TPM_TIS_STATE_COMPLETION:

                tis->loc[locty].r_offset = 0;

                tis->loc[locty].sts = TPM_TIS_STS_VALID |

                                      TPM_TIS_STS_DATA_AVAILABLE;

                break;

            default:

                /* ignore */

                break;

            }

        }

        break;

    case TPM_TIS_REG_DATA_FIFO:

        /* data fifo */

        if (tis->active_locty != locty) {

            break;

        }

        if (tis->loc[locty].state == TPM_TIS_STATE_IDLE ||

            tis->loc[locty].state == TPM_TIS_STATE_EXECUTION ||

            tis->loc[locty].state == TPM_TIS_STATE_COMPLETION) {

            /* drop the byte */

        } else {

            DPRINTF("tpm_tis: Byte to send to TPM: %02x\n", (uint8_t)val);

            if (tis->loc[locty].state == TPM_TIS_STATE_READY) {

                tis->loc[locty].state = TPM_TIS_STATE_RECEPTION;

                tis->loc[locty].sts = TPM_TIS_STS_EXPECT | TPM_TIS_STS_VALID;

            }

            if ((tis->loc[locty].sts & TPM_TIS_STS_EXPECT)) {

                if (tis->loc[locty].w_offset < tis->loc[locty].w_buffer.size) {

                    tis->loc[locty].w_buffer.

                        buffer[tis->loc[locty].w_offset++] = (uint8_t)val;

                } else {

                    tis->loc[locty].sts = TPM_TIS_STS_VALID;

                }

            }

            /* check for complete packet */

            if (tis->loc[locty].w_offset > 5 &&

                (tis->loc[locty].sts & TPM_TIS_STS_EXPECT)) {

                /* we have a packet length - see if we have all of it */

#ifdef RAISE_STS_IRQ

                bool needIrq = !(tis->loc[locty].sts & TPM_TIS_STS_VALID);

#endif

                len = tpm_tis_get_size_from_buffer(&tis->loc[locty].w_buffer);

                if (len > tis->loc[locty].w_offset) {

                    tis->loc[locty].sts = TPM_TIS_STS_EXPECT |

                                          TPM_TIS_STS_VALID;

                } else {

                    /* packet complete */

                    tis->loc[locty].sts = TPM_TIS_STS_VALID;

                }

#ifdef RAISE_STS_IRQ

                if (needIrq) {

                    tpm_tis_raise_irq(s, locty, TPM_TIS_INT_STS_VALID);

                }

#endif

            }

        }

        break;

    }

}

static void tpm_tis_mmio_write(void *opaque, hwaddr addr,

                               uint64_t val, unsigned size)

{

    return tpm_tis_mmio_write_intern(opaque, addr, val, size, false);

}

static const MemoryRegionOps tpm_tis_memory_ops = {

    .read = tpm_tis_mmio_read,

    .write = tpm_tis_mmio_write,

    .endianness = DEVICE_LITTLE_ENDIAN,

    .valid = {

        .min_access_size = 1,

        .max_access_size = 4,

    },

};

static int tpm_tis_do_startup_tpm(TPMState *s)

{

    return tpm_backend_startup_tpm(s->be_driver);

}

/*

 * This function is called when the machine starts, resets or due to

 * S3 resume.

 */

static void tpm_tis_reset(DeviceState *dev)

{

    TPMState *s = TPM(dev);

    TPMTISEmuState *tis = &s->s.tis;

    int c;

    tpm_backend_reset(s->be_driver);

    tis->active_locty = TPM_TIS_NO_LOCALITY;

    tis->next_locty = TPM_TIS_NO_LOCALITY;

    tis->aborting_locty = TPM_TIS_NO_LOCALITY;

    for (c = 0; c < TPM_TIS_NUM_LOCALITIES; c++) {

        tis->loc[c].access = TPM_TIS_ACCESS_TPM_REG_VALID_STS;

        tis->loc[c].sts = 0;

        tis->loc[c].inte = TPM_TIS_INT_POLARITY_LOW_LEVEL;

        tis->loc[c].ints = 0;

        tis->loc[c].state = TPM_TIS_STATE_IDLE;

        tis->loc[c].w_offset = 0;

        tpm_backend_realloc_buffer(s->be_driver, &tis->loc[c].w_buffer);

        tis->loc[c].r_offset = 0;

        tpm_backend_realloc_buffer(s->be_driver, &tis->loc[c].r_buffer);

    }

    tpm_tis_do_startup_tpm(s);

}

static const VMStateDescription vmstate_tpm_tis = {

    .name = "tpm",

    .unmigratable = 1,

};

static Property tpm_tis_properties[] = {

    DEFINE_PROP_UINT32("irq", TPMState,

                       s.tis.irq_num, TPM_TIS_IRQ),

    DEFINE_PROP_STRING("tpmdev", TPMState, backend),

    DEFINE_PROP_END_OF_LIST(),

};

static void tpm_tis_realizefn(DeviceState *dev, Error **errp)

{

    TPMState *s = TPM(dev);

    TPMTISEmuState *tis = &s->s.tis;

    s->be_driver = qemu_find_tpm(s->backend);

    if (!s->be_driver) {

        error_setg(errp, "tpm_tis: backend driver with id %s could not be "

                   "found", s->backend);

        return;

    }

    s->be_driver->fe_model = TPM_MODEL_TPM_TIS;

    if (tpm_backend_init(s->be_driver, s, tpm_tis_receive_cb)) {

        error_setg(errp, "tpm_tis: backend driver with id %s could not be "

                   "initialized", s->backend);

        return;

    }

    if (tis->irq_num > 15) {

        error_setg(errp, "tpm_tis: IRQ %d for TPM TIS is outside valid range "

                   "of 0 to 15.\n", tis->irq_num);

        return;

    }

    tis->bh = qemu_bh_new(tpm_tis_receive_bh, s);

    isa_init_irq(&s->busdev, &tis->irq, tis->irq_num);

}

static void tpm_tis_initfn(Object *obj)

{

    ISADevice *dev = ISA_DEVICE(obj);

    TPMState *s = TPM(obj);

    memory_region_init_io(&s->mmio, NULL, &tpm_tis_memory_ops, s, "tpm-tis-mmio",

                          TPM_TIS_NUM_LOCALITIES << TPM_TIS_LOCALITY_SHIFT);

    memory_region_add_subregion(isa_address_space(dev), TPM_TIS_ADDR_BASE,

                                &s->mmio);

}