// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2014 Intel Corporation
 *
 * Authors:
 * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
 *
 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
 *
 * This device driver implements the TPM interface as defined in
 * the TCG CRB 2.0 TPM specification.
 */

#include <linux/acpi.h>
#include <linux/highmem.h>
#include <linux/rculist.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#ifdef CONFIG_ARM64
#include <linux/arm-smccc.h>
#endif
#include "tpm_crb_ffa.h"
#include "tpm.h"

#define ACPI_SIG_TPM2 "TPM2"
#define TPM_CRB_MAX_RESOURCES 3

static const guid_t crb_acpi_start_guid =
        GUID_INIT(0x6BBF6CAB, 0x5463, 0x4714,
                  0xB7, 0xCD, 0xF0, 0x20, 0x3C, 0x03, 0x68, 0xD4);

enum crb_defaults {
        CRB_ACPI_START_REVISION_ID = 1,
        CRB_ACPI_START_INDEX = 1,
};

enum crb_loc_ctrl {
        CRB_LOC_CTRL_REQUEST_ACCESS     = BIT(0),
        CRB_LOC_CTRL_RELINQUISH         = BIT(1),
};

enum crb_loc_state {
        CRB_LOC_STATE_LOC_ASSIGNED      = BIT(1),
        CRB_LOC_STATE_TPM_REG_VALID_STS = BIT(7),
};

enum crb_ctrl_req {
        CRB_CTRL_REQ_CMD_READY  = BIT(0),
        CRB_CTRL_REQ_GO_IDLE    = BIT(1),
};

enum crb_ctrl_sts {
        CRB_CTRL_STS_ERROR      = BIT(0),
        CRB_CTRL_STS_TPM_IDLE   = BIT(1),
};

enum crb_start {
        CRB_START_INVOKE        = BIT(0),
};

enum crb_cancel {
        CRB_CANCEL_INVOKE       = BIT(0),
};

struct crb_regs_head {
        u32 loc_state;
        u32 reserved1;
        u32 loc_ctrl;
        u32 loc_sts;
        u8 reserved2[32];
        u64 intf_id;
        u64 ctrl_ext;
} __packed;

struct crb_regs_tail {
        u32 ctrl_req;
        u32 ctrl_sts;
        u32 ctrl_cancel;
        u32 ctrl_start;
        u32 ctrl_int_enable;
        u32 ctrl_int_sts;
        u32 ctrl_cmd_size;
        u32 ctrl_cmd_pa_low;
        u32 ctrl_cmd_pa_high;
        u32 ctrl_rsp_size;
        u64 ctrl_rsp_pa;
} __packed;

enum crb_status {
        CRB_DRV_STS_COMPLETE    = BIT(0),
};

struct crb_priv {
        u32 sm;
        const char *hid;
        struct crb_regs_head __iomem *regs_h;
        struct crb_regs_tail __iomem *regs_t;
        u8 __iomem *cmd;
        u8 __iomem *rsp;
        u32 cmd_size;
        u32 smc_func_id;
        u32 __iomem *pluton_start_addr;
        u32 __iomem *pluton_reply_addr;
        u8 ffa_flags;
        u8 ffa_attributes;
};

struct tpm2_crb_smc {
        u32 interrupt;
        u8 interrupt_flags;
        u8 op_flags;
        u16 reserved2;
        u32 smc_func_id;
};

/* CRB over FFA start method parameters in TCG2 ACPI table */
struct tpm2_crb_ffa {
        u8 flags;
        u8 attributes;
        u16 partition_id;
        u8 reserved[8];
};

struct tpm2_crb_pluton {
        u64 start_addr;
        u64 reply_addr;
};

/*
 * Returns true if the start method supports idle.
 */
static inline bool tpm_crb_has_idle(u32 start_method)
{
        return !(start_method == ACPI_TPM2_START_METHOD ||
               start_method == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD ||
               start_method == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC);
}

static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
                                unsigned long timeout)
{
        ktime_t start;
        ktime_t stop;

        start = ktime_get();
        stop = ktime_add(start, ms_to_ktime(timeout));

        do {
                if ((ioread32(reg) & mask) == value)
                        return true;

                usleep_range(50, 100);
        } while (ktime_before(ktime_get(), stop));

        return ((ioread32(reg) & mask) == value);
}

static int crb_try_pluton_doorbell(struct crb_priv *priv, bool wait_for_complete)
{
        if (priv->sm != ACPI_TPM2_COMMAND_BUFFER_WITH_PLUTON)
                return 0;

        if (!crb_wait_for_reg_32(priv->pluton_reply_addr, ~0, 1, TPM2_TIMEOUT_C))
                return -ETIME;

        iowrite32(1, priv->pluton_start_addr);
        if (wait_for_complete == false)
                return 0;

        if (!crb_wait_for_reg_32(priv->pluton_start_addr,
                                 0xffffffff, 0, 200))
                return -ETIME;

        return 0;
}

/**
 * __crb_go_idle - request tpm crb device to go the idle state
 *
 * @dev:  crb device
 * @priv: crb private data
 * @loc:  locality
 *
 * Write CRB_CTRL_REQ_GO_IDLE to TPM_CRB_CTRL_REQ
 * The device should respond within TIMEOUT_C by clearing the bit.
 * Anyhow, we do not wait here as a consequent CMD_READY request
 * will be handled correctly even if idle was not completed.
 *
 * The function does nothing for devices with ACPI-start method
 * or SMC-start method.
 *
 * Return: 0 always
 */
static int __crb_go_idle(struct device *dev, struct crb_priv *priv, int loc)
{
        int rc;

        if (!tpm_crb_has_idle(priv->sm))
                return 0;

        iowrite32(CRB_CTRL_REQ_GO_IDLE, &priv->regs_t->ctrl_req);

        if (priv->sm == ACPI_TPM2_CRB_WITH_ARM_FFA) {
                rc = tpm_crb_ffa_start(CRB_FFA_START_TYPE_COMMAND, loc);
                if (rc)
                        return rc;
        }

        rc = crb_try_pluton_doorbell(priv, true);
        if (rc)
                return rc;

        if (!crb_wait_for_reg_32(&priv->regs_t->ctrl_req,
                                 CRB_CTRL_REQ_GO_IDLE/* mask */,
                                 0, /* value */
                                 TPM2_TIMEOUT_C)) {
                dev_warn(dev, "goIdle timed out\n");
                return -ETIME;
        }

        return 0;
}

static int crb_go_idle(struct tpm_chip *chip)
{
        struct device *dev = &chip->dev;
        struct crb_priv *priv = dev_get_drvdata(dev);

        return __crb_go_idle(dev, priv, chip->locality);
}

/**
 * __crb_cmd_ready - request tpm crb device to enter ready state
 *
 * @dev:  crb device
 * @priv: crb private data
 * @loc:  locality
 *
 * Write CRB_CTRL_REQ_CMD_READY to TPM_CRB_CTRL_REQ
 * and poll till the device acknowledge it by clearing the bit.
 * The device should respond within TIMEOUT_C.
 *
 * The function does nothing for devices with ACPI-start method
 * or SMC-start method.
 *
 * Return: 0 on success -ETIME on timeout;
 */
static int __crb_cmd_ready(struct device *dev, struct crb_priv *priv, int loc)
{
        int rc;

        if (!tpm_crb_has_idle(priv->sm))
                return 0;

        iowrite32(CRB_CTRL_REQ_CMD_READY, &priv->regs_t->ctrl_req);

        if (priv->sm == ACPI_TPM2_CRB_WITH_ARM_FFA) {
                rc = tpm_crb_ffa_start(CRB_FFA_START_TYPE_COMMAND, loc);
                if (rc)
                        return rc;
        }

        rc = crb_try_pluton_doorbell(priv, true);
        if (rc)
                return rc;

        if (!crb_wait_for_reg_32(&priv->regs_t->ctrl_req,
                                 CRB_CTRL_REQ_CMD_READY /* mask */,
                                 0, /* value */
                                 TPM2_TIMEOUT_C)) {
                dev_warn(dev, "cmdReady timed out\n");
                return -ETIME;
        }

        return 0;
}

static int crb_cmd_ready(struct tpm_chip *chip)
{
        struct device *dev = &chip->dev;
        struct crb_priv *priv = dev_get_drvdata(dev);

        return __crb_cmd_ready(dev, priv, chip->locality);
}

static int __crb_request_locality(struct device *dev,
                                  struct crb_priv *priv, int loc)
{
        u32 value = CRB_LOC_STATE_LOC_ASSIGNED | CRB_LOC_STATE_TPM_REG_VALID_STS;
        int rc;

        if (!priv->regs_h)
                return 0;

        iowrite32(CRB_LOC_CTRL_REQUEST_ACCESS, &priv->regs_h->loc_ctrl);

        if (priv->sm == ACPI_TPM2_CRB_WITH_ARM_FFA) {
                rc = tpm_crb_ffa_start(CRB_FFA_START_TYPE_LOCALITY_REQUEST, loc);
                if (rc)
                        return rc;
        }

        if (!crb_wait_for_reg_32(&priv->regs_h->loc_state, value, value,
                                 TPM2_TIMEOUT_C)) {
                dev_warn(dev, "TPM_LOC_STATE_x.requestAccess timed out\n");
                return -ETIME;
        }

        return 0;
}

static int crb_request_locality(struct tpm_chip *chip, int loc)
{
        struct crb_priv *priv = dev_get_drvdata(&chip->dev);

        return __crb_request_locality(&chip->dev, priv, loc);
}

static int __crb_relinquish_locality(struct device *dev,
                                     struct crb_priv *priv, int loc)
{
        u32 mask = CRB_LOC_STATE_LOC_ASSIGNED | CRB_LOC_STATE_TPM_REG_VALID_STS;
        u32 value = CRB_LOC_STATE_TPM_REG_VALID_STS;
        int rc;

        if (!priv->regs_h)
                return 0;

        iowrite32(CRB_LOC_CTRL_RELINQUISH, &priv->regs_h->loc_ctrl);

        if (priv->sm == ACPI_TPM2_CRB_WITH_ARM_FFA) {
                rc = tpm_crb_ffa_start(CRB_FFA_START_TYPE_LOCALITY_REQUEST, loc);
                if (rc)
                        return rc;
        }

        if (!crb_wait_for_reg_32(&priv->regs_h->loc_state, mask, value,
                                 TPM2_TIMEOUT_C)) {
                dev_warn(dev, "TPM_LOC_STATE_x.Relinquish timed out\n");
                return -ETIME;
        }

        return 0;
}

static int crb_relinquish_locality(struct tpm_chip *chip, int loc)
{
        struct crb_priv *priv = dev_get_drvdata(&chip->dev);

        return __crb_relinquish_locality(&chip->dev, priv, loc);
}

static u8 crb_status(struct tpm_chip *chip)
{
        struct crb_priv *priv = dev_get_drvdata(&chip->dev);
        u8 sts = 0;

        if ((ioread32(&priv->regs_t->ctrl_start) & CRB_START_INVOKE) !=
            CRB_START_INVOKE)
                sts |= CRB_DRV_STS_COMPLETE;

        return sts;
}

static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
{
        struct crb_priv *priv = dev_get_drvdata(&chip->dev);
        unsigned int expected;

        /* A sanity check that the upper layer wants to get at least the header
         * as that is the minimum size for any TPM response.
         */
        if (count < TPM_HEADER_SIZE)
                return -EIO;

        /* If this bit is set, according to the spec, the TPM is in
         * unrecoverable condition.
         */
        if (ioread32(&priv->regs_t->ctrl_sts) & CRB_CTRL_STS_ERROR)
                return -EIO;

        /* Read the first 8 bytes in order to get the length of the response.
         * We read exactly a quad word in order to make sure that the remaining
         * reads will be aligned.
         */
        memcpy_fromio(buf, priv->rsp, 8);

        expected = be32_to_cpup((__be32 *)&buf[2]);
        if (expected > count || expected < TPM_HEADER_SIZE)
                return -EIO;

        memcpy_fromio(&buf[8], &priv->rsp[8], expected - 8);

        return expected;
}

static int crb_do_acpi_start(struct tpm_chip *chip)
{
        union acpi_object *obj;
        int rc;

        obj = acpi_evaluate_dsm(chip->acpi_dev_handle,
                                &crb_acpi_start_guid,
                                CRB_ACPI_START_REVISION_ID,
                                CRB_ACPI_START_INDEX,
                                NULL);
        if (!obj)
                return -ENXIO;
        rc = obj->integer.value == 0 ? 0 : -ENXIO;
        ACPI_FREE(obj);
        return rc;
}

#ifdef CONFIG_ARM64
/*
 * This is a TPM Command Response Buffer start method that invokes a
 * Secure Monitor Call to request the firmware to execute or cancel
 * a TPM 2.0 command.
 */
static int tpm_crb_smc_start(struct device *dev, unsigned long func_id)
{
        struct arm_smccc_res res;

        arm_smccc_smc(func_id, 0, 0, 0, 0, 0, 0, 0, &res);
        if (res.a0 != 0) {
                dev_err(dev,
                        FW_BUG "tpm_crb_smc_start() returns res.a0 = 0x%lx\n",
                        res.a0);
                return -EIO;
        }

        return 0;
}
#else
static int tpm_crb_smc_start(struct device *dev, unsigned long func_id)
{
        dev_err(dev, FW_BUG "tpm_crb: incorrect start method\n");
        return -EINVAL;
}
#endif

static int crb_send(struct tpm_chip *chip, u8 *buf, size_t bufsiz, size_t len)
{
        struct crb_priv *priv = dev_get_drvdata(&chip->dev);
        int rc = 0;

        /* Zero the cancel register so that the next command will not get
         * canceled.
         */
        iowrite32(0, &priv->regs_t->ctrl_cancel);

        if (len > priv->cmd_size) {
                dev_err(&chip->dev, "invalid command count value %zd %d\n",
                        len, priv->cmd_size);
                return -E2BIG;
        }

        /* Seems to be necessary for every command */
        if (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_PLUTON)
                __crb_cmd_ready(&chip->dev, priv, chip->locality);

        memcpy_toio(priv->cmd, buf, len);

        /* Make sure that cmd is populated before issuing start. */
        wmb();

        /* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
         * report only ACPI start but in practice seems to require both
         * CRB start, hence invoking CRB start method if hid == MSFT0101.
         */
        if (priv->sm == ACPI_TPM2_COMMAND_BUFFER ||
            priv->sm == ACPI_TPM2_MEMORY_MAPPED ||
            !strcmp(priv->hid, "MSFT0101"))
                iowrite32(CRB_START_INVOKE, &priv->regs_t->ctrl_start);

        if (priv->sm == ACPI_TPM2_START_METHOD ||
            priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)
                rc = crb_do_acpi_start(chip);

        if (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC) {
                iowrite32(CRB_START_INVOKE, &priv->regs_t->ctrl_start);
                rc = tpm_crb_smc_start(&chip->dev, priv->smc_func_id);
        }

        if (priv->sm == ACPI_TPM2_CRB_WITH_ARM_FFA) {
                iowrite32(CRB_START_INVOKE, &priv->regs_t->ctrl_start);
                rc = tpm_crb_ffa_start(CRB_FFA_START_TYPE_COMMAND, chip->locality);
        }

        if (rc)
                return rc;

        return crb_try_pluton_doorbell(priv, false);
}

static void crb_cancel(struct tpm_chip *chip)
{
        struct crb_priv *priv = dev_get_drvdata(&chip->dev);
        int rc;

        iowrite32(CRB_CANCEL_INVOKE, &priv->regs_t->ctrl_cancel);

        if ((priv->sm == ACPI_TPM2_START_METHOD ||
             priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD) &&
             crb_do_acpi_start(chip))
                dev_err(&chip->dev, "ACPI Start failed\n");

        if (priv->sm == ACPI_TPM2_CRB_WITH_ARM_FFA) {
                rc = tpm_crb_ffa_start(CRB_FFA_START_TYPE_COMMAND, chip->locality);
                if (rc)
                        dev_err(&chip->dev, "FF-A Start failed\n");
        }
}

static bool crb_req_canceled(struct tpm_chip *chip, u8 status)
{
        struct crb_priv *priv = dev_get_drvdata(&chip->dev);
        u32 cancel = ioread32(&priv->regs_t->ctrl_cancel);

        return (cancel & CRB_CANCEL_INVOKE) == CRB_CANCEL_INVOKE;
}

static const struct tpm_class_ops tpm_crb = {
        .flags = TPM_OPS_AUTO_STARTUP,
        .status = crb_status,
        .recv = crb_recv,
        .send = crb_send,
        .cancel = crb_cancel,
        .req_canceled = crb_req_canceled,
        .go_idle  = crb_go_idle,
        .cmd_ready = crb_cmd_ready,
        .request_locality = crb_request_locality,
        .relinquish_locality = crb_relinquish_locality,
        .req_complete_mask = CRB_DRV_STS_COMPLETE,
        .req_complete_val = CRB_DRV_STS_COMPLETE,
};

static int crb_check_resource(struct acpi_resource *ares, void *data)
{
        struct resource *iores_array = data;
        struct resource_win win;
        struct resource *res = &(win.res);
        int i;

        if (acpi_dev_resource_memory(ares, res) ||
            acpi_dev_resource_address_space(ares, &win)) {
                for (i = 0; i < TPM_CRB_MAX_RESOURCES + 1; ++i) {
                        if (resource_type(iores_array + i) != IORESOURCE_MEM) {
                                iores_array[i] = *res;
                                iores_array[i].name = NULL;
                                break;
                        }
                }
        }

        return 1;
}

static void __iomem *crb_map_res(struct device *dev, struct resource *iores,
                                 void __iomem **iobase_ptr, u64 start, u32 size)
{
        struct resource new_res = {
                .start  = start,
                .end    = start + size - 1,
                .flags  = IORESOURCE_MEM,
        };

        /* Detect a 64 bit address on a 32 bit system */
        if (start != new_res.start)
                return IOMEM_ERR_PTR(-EINVAL);

        if (!iores)
                return devm_ioremap_resource(dev, &new_res);

        if (!*iobase_ptr) {
                *iobase_ptr = devm_ioremap_resource(dev, iores);
                if (IS_ERR(*iobase_ptr))
                        return *iobase_ptr;
        }

        return *iobase_ptr + (new_res.start - iores->start);
}

/*
 * Work around broken BIOSs that return inconsistent values from the ACPI
 * region vs the registers. Trust the ACPI region. Such broken systems
 * probably cannot send large TPM commands since the buffer will be truncated.
 */
static u64 crb_fixup_cmd_size(struct device *dev, struct resource *io_res,
                              u64 start, u64 size)
{
        if (io_res->start > start || io_res->end < start)
                return size;

        if (start + size - 1 <= io_res->end)
                return size;

        dev_err(dev,
                FW_BUG "ACPI region does not cover the entire command/response buffer. %pr vs %llx %llx\n",
                io_res, start, size);

        return io_res->end - start + 1;
}

static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
                      struct acpi_table_tpm2 *buf)
{
        struct list_head acpi_resource_list;
        struct resource iores_array[TPM_CRB_MAX_RESOURCES + 1] = { {0} };
        void __iomem *iobase_array[TPM_CRB_MAX_RESOURCES] = {NULL};
        struct device *dev = &device->dev;
        struct resource *iores;
        void __iomem **iobase_ptr;
        int i;
        u32 pa_high, pa_low;
        u64 cmd_pa;
        u32 cmd_size;
        __le64 __rsp_pa;
        u64 rsp_pa;
        u32 rsp_size;
        int ret;

        /*
         * Pluton sometimes does not define ACPI memory regions.
         * Mapping is then done in crb_map_pluton
         */
        if (priv->sm != ACPI_TPM2_COMMAND_BUFFER_WITH_PLUTON) {
                INIT_LIST_HEAD(&acpi_resource_list);
                ret = acpi_dev_get_resources(device, &acpi_resource_list,
                                             crb_check_resource, iores_array);
                if (ret < 0)
                        return ret;
                acpi_dev_free_resource_list(&acpi_resource_list);

                if (resource_type(iores_array) != IORESOURCE_MEM) {
                        dev_err(dev, FW_BUG "TPM2 ACPI table does not define a memory resource\n");
                        return -EINVAL;
                } else if (resource_type(iores_array + TPM_CRB_MAX_RESOURCES) ==
                           IORESOURCE_MEM) {
                        dev_warn(dev, "TPM2 ACPI table defines too many memory resources\n");
                        memset(iores_array + TPM_CRB_MAX_RESOURCES,
                               0, sizeof(*iores_array));
                        iores_array[TPM_CRB_MAX_RESOURCES].flags = 0;
                }
        }

        iores = NULL;
        iobase_ptr = NULL;
        for (i = 0; resource_type(iores_array + i) == IORESOURCE_MEM; ++i) {
                if (buf->control_address >= iores_array[i].start &&
                    buf->control_address + sizeof(struct crb_regs_tail) - 1 <=
                    iores_array[i].end) {
                        iores = iores_array + i;
                        iobase_ptr = iobase_array + i;
                        break;
                }
        }

        priv->regs_t = crb_map_res(dev, iores, iobase_ptr, buf->control_address,
                                   sizeof(struct crb_regs_tail));

        if (IS_ERR(priv->regs_t))
                return PTR_ERR(priv->regs_t);

        /* The ACPI IO region starts at the head area and continues to include
         * the control area, as one nice sane region except for some older
         * stuff that puts the control area outside the ACPI IO region.
         */
        if (priv->sm == ACPI_TPM2_COMMAND_BUFFER ||
            priv->sm == ACPI_TPM2_CRB_WITH_ARM_FFA ||
            priv->sm == ACPI_TPM2_MEMORY_MAPPED) {
                if (iores &&
                    buf->control_address == iores->start +
                    sizeof(*priv->regs_h))
                        priv->regs_h = *iobase_ptr;
                else
                        dev_warn(dev, FW_BUG "Bad ACPI memory layout");
        }

        ret = __crb_request_locality(dev, priv, 0);
        if (ret)
                return ret;

        /*
         * PTT HW bug w/a: wake up the device to access
         * possibly not retained registers.
         */
        ret = __crb_cmd_ready(dev, priv, 0);
        if (ret)
                goto out_relinquish_locality;

        pa_high = ioread32(&priv->regs_t->ctrl_cmd_pa_high);
        pa_low  = ioread32(&priv->regs_t->ctrl_cmd_pa_low);
        cmd_pa = ((u64)pa_high << 32) | pa_low;
        cmd_size = ioread32(&priv->regs_t->ctrl_cmd_size);

        iores = NULL;
        iobase_ptr = NULL;
        for (i = 0; iores_array[i].end; ++i) {
                if (cmd_pa >= iores_array[i].start &&
                    cmd_pa <= iores_array[i].end) {
                        iores = iores_array + i;
                        iobase_ptr = iobase_array + i;
                        break;
                }
        }

        if (iores)
                cmd_size = crb_fixup_cmd_size(dev, iores, cmd_pa, cmd_size);

        dev_dbg(dev, "cmd_hi = %X cmd_low = %X cmd_size %X\n",
                pa_high, pa_low, cmd_size);

        priv->cmd = crb_map_res(dev, iores, iobase_ptr, cmd_pa, cmd_size);
        if (IS_ERR(priv->cmd)) {
                ret = PTR_ERR(priv->cmd);
                goto out;
        }

        memcpy_fromio(&__rsp_pa, &priv->regs_t->ctrl_rsp_pa, 8);
        rsp_pa = le64_to_cpu(__rsp_pa);
        rsp_size = ioread32(&priv->regs_t->ctrl_rsp_size);

        iores = NULL;
        iobase_ptr = NULL;
        for (i = 0; resource_type(iores_array + i) == IORESOURCE_MEM; ++i) {
                if (rsp_pa >= iores_array[i].start &&
                    rsp_pa <= iores_array[i].end) {
                        iores = iores_array + i;
                        iobase_ptr = iobase_array + i;
                        break;
                }
        }

        if (iores)
                rsp_size = crb_fixup_cmd_size(dev, iores, rsp_pa, rsp_size);

        if (cmd_pa != rsp_pa) {
                priv->rsp = crb_map_res(dev, iores, iobase_ptr,
                                        rsp_pa, rsp_size);
                ret = PTR_ERR_OR_ZERO(priv->rsp);
                goto out;
        }

        /* According to the PTP specification, overlapping command and response
         * buffer sizes must be identical.
         */
        if (cmd_size != rsp_size) {
                dev_err(dev, FW_BUG "overlapping command and response buffer sizes are not identical");
                ret = -EINVAL;
                goto out;
        }

        priv->rsp = priv->cmd;

out:
        if (!ret)
                priv->cmd_size = cmd_size;

        __crb_go_idle(dev, priv, 0);

out_relinquish_locality:

        __crb_relinquish_locality(dev, priv, 0);

        return ret;
}

static int crb_map_pluton(struct device *dev, struct crb_priv *priv,
               struct acpi_table_tpm2 *buf, struct tpm2_crb_pluton *crb_pluton)
{
        priv->pluton_start_addr = crb_map_res(dev, NULL, NULL,
                                              crb_pluton->start_addr, 4);
        if (IS_ERR(priv->pluton_start_addr))
                return PTR_ERR(priv->pluton_start_addr);

        priv->pluton_reply_addr = crb_map_res(dev, NULL, NULL,
                                              crb_pluton->reply_addr, 4);
        if (IS_ERR(priv->pluton_reply_addr))
                return PTR_ERR(priv->pluton_reply_addr);

        return 0;
}

static int crb_acpi_add(struct acpi_device *device)
{
        struct acpi_table_tpm2 *buf;
        struct crb_priv *priv;
        struct tpm_chip *chip;
        struct device *dev = &device->dev;
        struct tpm2_crb_smc *crb_smc;
        struct tpm2_crb_ffa *crb_ffa;
        struct tpm2_crb_pluton *crb_pluton;
        acpi_status status;
        u32 sm;
        int rc;

        status = acpi_get_table(ACPI_SIG_TPM2, 1,
                                (struct acpi_table_header **) &buf);
        if (ACPI_FAILURE(status) || buf->header.length < sizeof(*buf)) {
                dev_err(dev, FW_BUG "failed to get TPM2 ACPI table\n");
                return -EINVAL;
        }

        /* Should the FIFO driver handle this? */
        sm = buf->start_method;
        if (sm == ACPI_TPM2_MEMORY_MAPPED) {
                rc = -ENODEV;
                goto out;
        }

        priv = devm_kzalloc(dev, sizeof(struct crb_priv), GFP_KERNEL);
        if (!priv) {
                rc = -ENOMEM;
                goto out;
        }

        if (sm == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC) {
                if (buf->header.length < (sizeof(*buf) + sizeof(*crb_smc))) {
                        dev_err(dev,
                                FW_BUG "TPM2 ACPI table has wrong size %u for start method type %d\n",
                                buf->header.length,
                                ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC);
                        rc = -EINVAL;
                        goto out;
                }
                crb_smc = ACPI_ADD_PTR(struct tpm2_crb_smc, buf, sizeof(*buf));
                priv->smc_func_id = crb_smc->smc_func_id;
        }

        if (sm == ACPI_TPM2_CRB_WITH_ARM_FFA) {
                if (buf->header.length < (sizeof(*buf) + sizeof(*crb_ffa))) {
                        dev_err(dev,
                                FW_BUG "TPM2 ACPI table has wrong size %u for start method type %d\n",
                                buf->header.length,
                                ACPI_TPM2_CRB_WITH_ARM_FFA);
                        rc = -EINVAL;
                        goto out;
                }
                crb_ffa = ACPI_ADD_PTR(struct tpm2_crb_ffa, buf, sizeof(*buf));
                priv->ffa_flags = crb_ffa->flags;
                priv->ffa_attributes = crb_ffa->attributes;
                rc = tpm_crb_ffa_init();
                if (rc) {
                        /* If FF-A driver is not available yet, request probe retry */
                        if (rc == -ENOENT)
                                rc = -EPROBE_DEFER;
                        goto out;
                }
        }

        if (sm == ACPI_TPM2_COMMAND_BUFFER_WITH_PLUTON) {
                if (buf->header.length < (sizeof(*buf) + sizeof(*crb_pluton))) {
                        dev_err(dev,
                                FW_BUG "TPM2 ACPI table has wrong size %u for start method type %d\n",
                                buf->header.length,
                                ACPI_TPM2_COMMAND_BUFFER_WITH_PLUTON);
                        rc = -EINVAL;
                        goto out;
                }
                crb_pluton = ACPI_ADD_PTR(struct tpm2_crb_pluton, buf, sizeof(*buf));
                rc = crb_map_pluton(dev, priv, buf, crb_pluton);
                if (rc)
                        goto out;
        }

        priv->sm = sm;
        priv->hid = acpi_device_hid(device);

        rc = crb_map_io(device, priv, buf);
        if (rc)
                goto out;

        chip = tpmm_chip_alloc(dev, &tpm_crb);
        if (IS_ERR(chip)) {
                rc = PTR_ERR(chip);
                goto out;
        }

        dev_set_drvdata(&chip->dev, priv);
        chip->acpi_dev_handle = device->handle;
        chip->flags = TPM_CHIP_FLAG_TPM2;

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

#ifdef CONFIG_X86
        /* A quirk for https://www.amd.com/en/support/kb/faq/pa-410 */
        if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
            priv->sm != ACPI_TPM2_COMMAND_BUFFER_WITH_PLUTON) {
                dev_info(dev, "Disabling hwrng\n");
                chip->flags |= TPM_CHIP_FLAG_HWRNG_DISABLED;
        }
#endif /* CONFIG_X86 */

        rc = tpm_chip_register(chip);

out:
        acpi_put_table((struct acpi_table_header *)buf);
        return rc;
}

static void crb_acpi_remove(struct acpi_device *device)
{
        struct device *dev = &device->dev;
        struct tpm_chip *chip = dev_get_drvdata(dev);

        tpm_chip_unregister(chip);
}

static const struct dev_pm_ops crb_pm = {
        SET_SYSTEM_SLEEP_PM_OPS(tpm_pm_suspend, tpm_pm_resume)
};

static const struct acpi_device_id crb_device_ids[] = {
        {"MSFT0101", 0},
        {"", 0},
};
MODULE_DEVICE_TABLE(acpi, crb_device_ids);

static struct acpi_driver crb_acpi_driver = {
        .name = "tpm_crb",
        .ids = crb_device_ids,
        .ops = {
                .add = crb_acpi_add,
                .remove = crb_acpi_remove,
        },
        .drv = {
                .pm = &crb_pm,
        },
};

module_acpi_driver(crb_acpi_driver);
MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
MODULE_DESCRIPTION("TPM2 Driver");
MODULE_VERSION("0.1");
MODULE_LICENSE("GPL");