/*-
 * Copyright (c) 2018 Stormshield.
 * Copyright (c) 2018 Semihalf.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#include "tpm20.h"

/*
 * CRB register space as defined in
 * TCG_PC_Client_Platform_TPM_Profile_PTP_2.0_r1.03_v22
 */
#define TPM_LOC_STATE                   0x0
#define TPM_LOC_CTRL                    0x8
#define TPM_LOC_STS                     0xC
#define TPM_CRB_INTF_ID                 0x30
#define TPM_CRB_CTRL_EXT                0x38
#define TPM_CRB_CTRL_REQ                0x40
#define TPM_CRB_CTRL_STS                0x44
#define TPM_CRB_CTRL_CANCEL             0x48
#define TPM_CRB_CTRL_START              0x4C
#define TPM_CRB_INT_ENABLE              0x50
#define TPM_CRB_INT_STS                 0x54
#define TPM_CRB_CTRL_CMD_SIZE           0x58
#define TPM_CRB_CTRL_CMD_LADDR          0x5C
#define TPM_CRB_CTRL_CMD_HADDR          0x60
#define TPM_CRB_CTRL_RSP_SIZE           0x64
#define TPM_CRB_CTRL_RSP_ADDR           0x68
#define TPM_CRB_CTRL_RSP_HADDR          0x6c
#define TPM_CRB_DATA_BUFFER             0x80

#define TPM_LOC_STATE_ESTB              BIT(0)
#define TPM_LOC_STATE_ASSIGNED          BIT(1)
#define TPM_LOC_STATE_ACTIVE_MASK       0x9C
#define TPM_LOC_STATE_VALID             BIT(7)

#define TPM_CRB_INTF_ID_TYPE_CRB        0x1
#define TPM_CRB_INTF_ID_TYPE            0x7

#define TPM_LOC_CTRL_REQUEST            BIT(0)
#define TPM_LOC_CTRL_RELINQUISH         BIT(1)

#define TPM_CRB_CTRL_REQ_GO_READY       BIT(0)
#define TPM_CRB_CTRL_REQ_GO_IDLE        BIT(1)

#define TPM_CRB_CTRL_STS_ERR_BIT        BIT(0)
#define TPM_CRB_CTRL_STS_IDLE_BIT       BIT(1)

#define TPM_CRB_CTRL_CANCEL_CMD         0x1
#define TPM_CRB_CTRL_CANCEL_CLEAR       0x0

#define TPM_CRB_CTRL_START_CMD          BIT(0)

#define TPM_CRB_INT_ENABLE_BIT          BIT(31)

struct tpmcrb_sc;
/* Attach */
typedef bool (sm_attach_t)(struct tpmcrb_sc *, void *, size_t);
/* State change notification (timeout == 0 for 'no timeout') */
typedef bool (sm_statechange_t)(struct tpmcrb_sc *, int);

struct tpmcrb_sm_cfg {
        sm_attach_t             *sm_attach;
        sm_statechange_t        *sm_statechange;
        sm_statechange_t        *sm_cmdready;
};

static sm_attach_t              pluton_attach;
static sm_statechange_t         pluton_doorbell;

static const struct tpmcrb_sm_cfg_map {
        int                             acpi_sm;
        const char                      *desc;
        const struct tpmcrb_sm_cfg      sm_cfg;
} tpmcrb_sm_cfg_map[] = {
        {
                .acpi_sm = TPM2_START_METHOD_CRB,
                .desc = "Trusted Platform Module 2.0, CRB mode",
                .sm_cfg = { NULL },     /* No notifications required */
        },
        {
                .acpi_sm = ACPI_TPM2_COMMAND_BUFFER_WITH_PLUTON,
                .desc = "Trusted Platform Module 2.0, CRB mode (Pluton)",
                .sm_cfg = {
                        .sm_attach = &pluton_attach,
                        .sm_statechange = &pluton_doorbell,
                        .sm_cmdready = &pluton_doorbell,
                },
        },
};

struct tpmcrb_sc {
        struct tpm_sc   base;
        const struct tpmcrb_sm_cfg      *sm_cfg;
        union {
                /* StartMethod data */
                struct {
                        uint64_t         start_reg;
                        uint64_t         reply_reg;
                } pluton;
        };
        bus_size_t      cmd_off;
        bus_size_t      rsp_off;
        size_t          cmd_buf_size;
        size_t          rsp_buf_size;
};

int tpmcrb_transmit(device_t dev, struct tpm_priv *priv, size_t size);

static int tpmcrb_acpi_probe(device_t dev);
static int tpmcrb_attach(device_t dev);
static int tpmcrb_detach(device_t dev);

static ACPI_STATUS tpmcrb_fix_buff_offsets(ACPI_RESOURCE *res, void *arg);

static bool tpm_wait_for_u32(struct tpm_sc *sc, bus_size_t off,
    uint32_t mask, uint32_t val, int32_t timeout);
static bool tpmcrb_request_locality(struct tpm_sc *sc, int locality);
static void tpmcrb_relinquish_locality(struct tpm_sc *sc);
static bool tpmcrb_cancel_cmd(struct tpm_sc *sc);

char *tpmcrb_ids[] = {"MSFT0101", NULL};

static const struct tpmcrb_sm_cfg_map *
tpmcrb_acpi_startmethod_cfg(int method)
{
        const struct tpmcrb_sm_cfg_map *entry;

        for (size_t i = 0; i < nitems(tpmcrb_sm_cfg_map); i++) {
                entry = &tpmcrb_sm_cfg_map[i];

                if (method == entry->acpi_sm)
                        return (entry);
        }

        return (NULL);
}

static int
tpmcrb_acpi_probe(device_t dev)
{
        int err, smethod;
        const struct tpmcrb_sm_cfg_map *sm_cfg_map;
        ACPI_TABLE_TPM23 *tbl;
        ACPI_STATUS status;

        err = ACPI_ID_PROBE(device_get_parent(dev), dev, tpmcrb_ids, NULL);
        if (err > 0)
                return (err);
        /*Find TPM2 Header*/
        status = AcpiGetTable(ACPI_SIG_TPM2, 1, (ACPI_TABLE_HEADER **) &tbl);
        if (ACPI_FAILURE(status))
                return (ENXIO);

        smethod = tbl->StartMethod;
        AcpiPutTable((ACPI_TABLE_HEADER *)tbl);

        sm_cfg_map = tpmcrb_acpi_startmethod_cfg(smethod);
        if (sm_cfg_map == NULL)
                return (ENXIO);

        device_set_desc(dev, sm_cfg_map->desc);
        return (0);
}

static ACPI_STATUS
tpmcrb_fix_buff_offsets(ACPI_RESOURCE *res, void *arg)
{
        struct tpmcrb_sc *crb_sc;
        size_t length;
        uint32_t base_addr;

        crb_sc = (struct tpmcrb_sc *)arg;

        if (res->Type != ACPI_RESOURCE_TYPE_FIXED_MEMORY32)
                return (AE_OK);

        base_addr = res->Data.FixedMemory32.Address;
        length = res->Data.FixedMemory32.AddressLength;

        if (crb_sc->cmd_off > base_addr && crb_sc->cmd_off < base_addr + length)
                crb_sc->cmd_off -= base_addr;
        if (crb_sc->rsp_off > base_addr && crb_sc->rsp_off < base_addr + length)
                crb_sc->rsp_off -= base_addr;

        return (AE_OK);
}

static bool
tpmcrb_attach_startmethod(struct tpmcrb_sc *crb_sc)
{
        const struct tpmcrb_sm_cfg_map *sm_cfg_map;
        const struct tpmcrb_sm_cfg *sm_cfg;
        ACPI_TABLE_TPM23 *tbl;
        void *smdata;
        ACPI_STATUS status;
        bool ret;

        /*
         * Grab what we need from the StartMethod.
         */
        status = AcpiGetTable(ACPI_SIG_TPM2, 1, (ACPI_TABLE_HEADER **)(void **)&tbl);
        if (ACPI_FAILURE(status))
                return (false);

        sm_cfg_map = tpmcrb_acpi_startmethod_cfg(tbl->StartMethod);
        MPASS(sm_cfg_map != NULL);
        sm_cfg = &sm_cfg_map->sm_cfg;

        crb_sc->sm_cfg = sm_cfg;
        smdata = tbl + 1;
        if (sm_cfg->sm_attach != NULL) {
                ret = (*sm_cfg->sm_attach)(crb_sc, smdata,
                    tbl->Header.Length - sizeof(*tbl));
        } else {
                ret = true;
        }

        AcpiPutTable((ACPI_TABLE_HEADER *)tbl);
        return (ret);
}

static int
tpmcrb_attach(device_t dev)
{
        struct tpmcrb_sc *crb_sc;
        struct tpm_sc *sc;
        ACPI_HANDLE handle;
        ACPI_STATUS status;
        int result;

        crb_sc = device_get_softc(dev);
        sc = &crb_sc->base;
        handle = acpi_get_handle(dev);
        sc->dev = dev;

        sx_init(&sc->dev_lock, "TPM driver lock");

        sc->mem_rid = 0;
        sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &sc->mem_rid,
                                             RF_ACTIVE);
        if (sc->mem_res == NULL) {
                tpmcrb_detach(dev);
                return (ENXIO);
        }

        if (!tpmcrb_attach_startmethod(crb_sc)) {
                tpmcrb_detach(dev);
                return (ENXIO);
        }

        if(!tpmcrb_request_locality(sc, 0)) {
                tpmcrb_detach(dev);
                return (ENXIO);
        }

        /*
         * Disable all interrupts for now, since I don't have a device that
         * works in CRB mode and supports them.
         */
        AND4(sc, TPM_CRB_INT_ENABLE, ~TPM_CRB_INT_ENABLE_BIT);
        sc->interrupts = false;

        /*
         * Read addresses of Tx/Rx buffers and their sizes. Note that they
         * can be implemented by a single buffer. Also for some reason CMD
         * addr is stored in two 4 byte neighboring registers, whereas RSP is
         * stored in a single 8 byte one.
         */
#ifdef __amd64__
        crb_sc->rsp_off = TPM_READ_8(sc->dev, TPM_CRB_CTRL_RSP_ADDR);
#else
        crb_sc->rsp_off = TPM_READ_4(sc->dev, TPM_CRB_CTRL_RSP_ADDR);
        crb_sc->rsp_off |= ((uint64_t) TPM_READ_4(sc->dev, TPM_CRB_CTRL_RSP_HADDR) << 32);
#endif
        crb_sc->cmd_off = TPM_READ_4(sc->dev, TPM_CRB_CTRL_CMD_LADDR);
        crb_sc->cmd_off |= ((uint64_t) TPM_READ_4(sc->dev, TPM_CRB_CTRL_CMD_HADDR) << 32);
        crb_sc->cmd_buf_size = TPM_READ_4(sc->dev, TPM_CRB_CTRL_CMD_SIZE);
        crb_sc->rsp_buf_size = TPM_READ_4(sc->dev, TPM_CRB_CTRL_RSP_SIZE);

        tpmcrb_relinquish_locality(sc);

        /* Emulator returns address in acpi space instead of an offset */
        status = AcpiWalkResources(handle, "_CRS", tpmcrb_fix_buff_offsets,
                    (void *)crb_sc);
        if (ACPI_FAILURE(status)) {
                tpmcrb_detach(dev);
                return (ENXIO);
        }

        if (crb_sc->rsp_off == crb_sc->cmd_off) {
                /*
                 * If Tx/Rx buffers are implemented as one they have to be of
                 * same size
                 */
                if (crb_sc->cmd_buf_size != crb_sc->rsp_buf_size) {
                        device_printf(sc->dev,
                            "Overlapping Tx/Rx buffers have different sizes\n");
                        tpmcrb_detach(dev);
                        return (ENXIO);
                }
        }

        result = tpm20_init(sc);
        if (result != 0)
                tpmcrb_detach(dev);

        return (result);
}

static int
tpmcrb_detach(device_t dev)
{
        struct tpm_sc *sc;

        sc = device_get_softc(dev);
        tpm20_release(sc);

        if (sc->mem_res != NULL)
                bus_release_resource(dev, SYS_RES_MEMORY,
                    sc->mem_rid, sc->mem_res);

        return (0);
}

static bool
tpm_wait_for_u32(struct tpm_sc *sc, bus_size_t off, uint32_t mask, uint32_t val,
    int32_t timeout)
{

        /* Check for condition */
        if ((TPM_READ_4(sc->dev, off) & mask) == val)
                return (true);

        while (timeout > 0) {
                if ((TPM_READ_4(sc->dev, off) & mask) == val)
                        return (true);

                pause("TPM in polling mode", 1);
                timeout -= tick;
        }
        return (false);
}

static bool
tpmcrb_request_locality(struct tpm_sc *sc, int locality)
{
        uint32_t mask;

        /* Currently we only support Locality 0 */
        if (locality != 0)
                return (false);

        mask = TPM_LOC_STATE_VALID | TPM_LOC_STATE_ASSIGNED;

        OR4(sc, TPM_LOC_CTRL, TPM_LOC_CTRL_REQUEST);
        if (!tpm_wait_for_u32(sc, TPM_LOC_STATE, mask, mask, TPM_TIMEOUT_C))
                return (false);

        return (true);
}

static void
tpmcrb_relinquish_locality(struct tpm_sc *sc)
{

        OR4(sc, TPM_LOC_CTRL, TPM_LOC_CTRL_RELINQUISH);
}

static bool
tpmcrb_cancel_cmd(struct tpm_sc *sc)
{
        uint32_t mask = ~0;

        TPM_WRITE_4(sc->dev, TPM_CRB_CTRL_CANCEL, TPM_CRB_CTRL_CANCEL_CMD);
        if (!tpm_wait_for_u32(sc, TPM_CRB_CTRL_START,
                    mask, ~mask, TPM_TIMEOUT_B)) {
                device_printf(sc->dev,
                    "Device failed to cancel command\n");
                return (false);
        }

        TPM_WRITE_4(sc->dev, TPM_CRB_CTRL_CANCEL, TPM_CRB_CTRL_CANCEL_CLEAR);
        return (true);
}

static bool
tpmcrb_notify_cmdready(struct tpmcrb_sc *crb_sc, int timeout)
{
        sm_statechange_t *cmdready_fn;

        cmdready_fn = crb_sc->sm_cfg->sm_cmdready;
        if (cmdready_fn == NULL)
                return (true);

        return ((*cmdready_fn)(crb_sc, timeout));
}

static bool
tpmcrb_notify_state_changing(struct tpmcrb_sc *crb_sc, int timeout)
{
        sm_statechange_t *statechange_fn;

        statechange_fn = crb_sc->sm_cfg->sm_statechange;
        if (statechange_fn == NULL)
                return (true);

        return ((*statechange_fn)(crb_sc, timeout));
}

static bool
tpmcrb_state_idle(struct tpmcrb_sc *crb_sc, bool wait)
{
        struct tpm_sc *sc;
        int mask, timeout;

        timeout = wait ? TPM_TIMEOUT_C : 0;

        sc = &crb_sc->base;
        OR4(sc, TPM_CRB_CTRL_REQ, TPM_CRB_CTRL_REQ_GO_IDLE);

        if (!tpmcrb_notify_state_changing(crb_sc, timeout))
                return (false);

        if (timeout > 0) {
                mask = TPM_CRB_CTRL_STS_IDLE_BIT;
                if (!tpm_wait_for_u32(sc, TPM_CRB_CTRL_STS, mask, mask,
                    timeout))
                        return (false);
        }

        return (true);
}

static bool
tpmcrb_state_ready(struct tpmcrb_sc *crb_sc, bool wait)
{
        struct tpm_sc *sc;
        int mask, timeout;

        timeout = wait ? TPM_TIMEOUT_C : 0;

        sc = &crb_sc->base;
        OR4(sc, TPM_CRB_CTRL_REQ, TPM_CRB_CTRL_REQ_GO_READY);

        if (!tpmcrb_notify_state_changing(crb_sc, timeout))
                return (false);

        if (timeout > 0) {
                mask = TPM_CRB_CTRL_REQ_GO_READY;
                if (!tpm_wait_for_u32(sc, TPM_CRB_CTRL_STS, mask, !mask,
                    timeout))
                        return (false);
        }

        return (true);
}

int
tpmcrb_transmit(device_t dev, struct tpm_priv *priv, size_t length)
{
        struct tpmcrb_sc *crb_sc;
        struct tpm_sc *sc;
        uint32_t mask, curr_cmd;
        int timeout, bytes_available;

        crb_sc = device_get_softc(dev);
        sc = &crb_sc->base;

        sx_assert(&sc->dev_lock, SA_XLOCKED);

        if (length > crb_sc->cmd_buf_size) {
                device_printf(dev,
                    "Requested transfer is bigger than buffer size\n");
                return (E2BIG);
        }

        if (TPM_READ_4(dev, TPM_CRB_CTRL_STS) & TPM_CRB_CTRL_STS_ERR_BIT) {
                device_printf(dev,
                    "Device has Error bit set\n");
                return (EIO);
        }
        if (!tpmcrb_request_locality(sc, 0)) {
                device_printf(dev,
                    "Failed to obtain locality\n");
                return (EIO);
        }
        /* Clear cancellation bit */
        TPM_WRITE_4(dev, TPM_CRB_CTRL_CANCEL, TPM_CRB_CTRL_CANCEL_CLEAR);

        /* Switch device to idle state if necessary */
        if (!(TPM_READ_4(dev, TPM_CRB_CTRL_STS) & TPM_CRB_CTRL_STS_IDLE_BIT)) {
                if (!tpmcrb_state_idle(crb_sc, true)) {
                        device_printf(dev,
                            "Failed to transition to idle state\n");
                        return (EIO);
                }
        }

        /* Switch to ready state */
        if (!tpmcrb_state_ready(crb_sc, true)) {
                device_printf(dev,
                    "Failed to transition to ready state\n");
                return (EIO);
        }

        /*
         * Calculate timeout for current command.
         * Command code is passed in bytes 6-10.
         */
        curr_cmd = be32toh(*(uint32_t *) (&priv->buf[6]));
        timeout = tpm20_get_timeout(curr_cmd);

        /* Send command and tell device to process it. */
        bus_write_region_stream_1(sc->mem_res, crb_sc->cmd_off,
            priv->buf, length);
        TPM_WRITE_BARRIER(dev, crb_sc->cmd_off, length);

        TPM_WRITE_4(dev, TPM_CRB_CTRL_START, TPM_CRB_CTRL_START_CMD);
        TPM_WRITE_BARRIER(dev, TPM_CRB_CTRL_START, 4);

        if (!tpmcrb_notify_cmdready(crb_sc, timeout)) {
                device_printf(dev,
                    "Timeout while waiting for device to ready\n");
                if (!tpmcrb_cancel_cmd(sc))
                        return (EIO);
        }

        mask = ~0;
        if (!tpm_wait_for_u32(sc, TPM_CRB_CTRL_START, mask, ~mask, timeout)) {
                device_printf(dev,
                    "Timeout while waiting for device to process cmd\n");
                if (!tpmcrb_cancel_cmd(sc))
                        return (EIO);
        }

        /* Read response header. Length is passed in bytes 2 - 6. */
        bus_read_region_stream_1(sc->mem_res, crb_sc->rsp_off,
            priv->buf, TPM_HEADER_SIZE);
        bytes_available = be32toh(*(uint32_t *) (&priv->buf[2]));

        if (bytes_available > TPM_BUFSIZE || bytes_available < TPM_HEADER_SIZE) {
                device_printf(dev,
                    "Incorrect response size: %d\n",
                    bytes_available);
                return (EIO);
        }

        bus_read_region_stream_1(sc->mem_res, crb_sc->rsp_off + TPM_HEADER_SIZE,
              &priv->buf[TPM_HEADER_SIZE], bytes_available - TPM_HEADER_SIZE);

        /*
         * No need to wait for the transition to idle on the way out, we can
         * relinquish locality right away.
         */
        if (!tpmcrb_state_idle(crb_sc, false)) {
                device_printf(dev,
                    "Failed to transition to idle state post-send\n");
                return (EIO);
        }

        tpmcrb_relinquish_locality(sc);
        priv->offset = 0;
        priv->len = bytes_available;

        return (0);
}

/* StartMethod Implementation Details */

/** Pluton **/
struct tpmcrb_startmethod_pluton {
        uint64_t                sm_startaddr;
        uint64_t                sm_replyaddr;
};

static bool
pluton_attach(struct tpmcrb_sc *crb_sc, void *smdataregion, size_t datasz)
{
        struct tpmcrb_startmethod_pluton *smdata;
        struct tpm_sc *sc;
        rman_res_t base_addr, end_addr;

        if (datasz < sizeof(*smdata))
                return (false);

        smdata = smdataregion;
        sc = &crb_sc->base;

        base_addr = rman_get_start(sc->mem_res);
        end_addr = rman_get_end(sc->mem_res);
        /* Sanity check */
        if (smdata->sm_startaddr < base_addr ||
            smdata->sm_startaddr > end_addr ||
            smdata->sm_replyaddr < base_addr ||
            smdata->sm_replyaddr > end_addr)
                return (false);

        crb_sc->pluton.start_reg = smdata->sm_startaddr - base_addr;
        crb_sc->pluton.reply_reg = smdata->sm_replyaddr - base_addr;
        return (true);
}

static bool
pluton_doorbell(struct tpmcrb_sc *crb_sc, int timeout)
{
        struct tpm_sc *sc;
        device_t dev;

        sc = &crb_sc->base;
        dev = sc->dev;
        TPM_WRITE_4(dev, crb_sc->pluton.start_reg, 1);
        TPM_WRITE_BARRIER(dev, crb_sc->pluton.start_reg, 4);

        if (timeout > 0) {
                if (!tpm_wait_for_u32(sc, crb_sc->pluton.reply_reg, ~0U, 1,
                    timeout))
                        return (false);
        }

        return (true);
}

/* ACPI Driver */
static device_method_t  tpmcrb_methods[] = {
        DEVMETHOD(device_probe,         tpmcrb_acpi_probe),
        DEVMETHOD(device_attach,        tpmcrb_attach),
        DEVMETHOD(device_detach,        tpmcrb_detach),
        DEVMETHOD(device_shutdown,      tpm20_shutdown),
        DEVMETHOD(device_suspend,       tpm20_suspend),
        DEVMETHOD(device_resume,        tpm20_resume),
        DEVMETHOD(tpm_transmit,         tpmcrb_transmit),
        {0, 0}
};

DEFINE_CLASS_1(tpmcrb, tpmcrb_driver, tpmcrb_methods, sizeof(struct tpmcrb_sc),
    tpm_bus_driver);

DRIVER_MODULE(tpmcrb, acpi, tpmcrb_driver, 0, 0);