/* SPDX-License-Identifier: GPL-2.0+ */
/*
 * Copyright (c) 2013 The Chromium OS Authors.
 * Coypright (c) 2013 Guntermann & Drunck GmbH
 */

#ifndef __TPM_COMMON_H
#define __TPM_COMMON_H

#include <command.h>

struct udevice;

enum tpm_duration {
        TPM_SHORT = 0,
        TPM_MEDIUM = 1,
        TPM_LONG = 2,
        TPM_UNDEFINED,

        TPM_DURATION_COUNT,
};

/*
 * Here is a partial implementation of TPM commands.  Please consult TCG Main
 * Specification for definitions of TPM commands.
 */

#define TPM_HEADER_SIZE         10

/* Max buffer size supported by our tpm */
#define TPM_DEV_BUFSIZE         1260

#define TPM_PCR_MINIMUM_DIGEST_SIZE 20

/**
 * enum tpm_version - The version of the TPM stack to be used
 * @TPM_V1:             Use TPM v1.x stack
 * @TPM_V2:             Use TPM v2.x stack
 */
enum tpm_version {
        TPM_V1 = 0,
        TPM_V2,
};

/**
 * struct tpm_chip_priv - Information about a TPM, stored by the uclass
 *
 * These values must be set up by the device's probe() method before
 * communcation is attempted. If the device has an xfer() method, this is
 * not needed. There is no need to set up @buf.
 *
 * @version:            TPM stack to be used
 * @duration_ms:        Length of each duration type in milliseconds
 * @retry_time_ms:      Time to wait before retrying receive
 * @buf:                Buffer used during the exchanges with the chip
 * @pcr_count:          Number of PCR per bank
 * @pcr_select_min:     Minimum size in bytes of the pcrSelect array
 * @plat_hier_disabled: Platform hierarchy has been disabled (TPM is locked
 *                      down until next reboot)
 */
struct tpm_chip_priv {
        enum tpm_version version;

        uint duration_ms[TPM_DURATION_COUNT];
        uint retry_time_ms;
        u8 buf[TPM_DEV_BUFSIZE + sizeof(u8)];  /* Max buffer size + addr */

        /* TPM v2 specific data */
        uint pcr_count;
        uint pcr_select_min;
        bool plat_hier_disabled;
};

/**
 * struct tpm_ops - low-level TPM operations
 *
 * These are designed to avoid loops and delays in the driver itself. These
 * should be handled in the uclass.
 *
 * In gneral you should implement everything except xfer(). Where you need
 * complete control of the transfer, then xfer() can be provided and will
 * override the other methods.
 *
 * This interface is for low-level TPM access. It does not understand the
 * concept of localities or the various TPM messages. That interface is
 * defined in the functions later on in this file, but they all translate
 * to bytes which are sent and received.
 */
struct tpm_ops {
        /**
         * open() - Request access to locality 0 for the caller
         *
         * After all commands have been completed the caller should call
         * close().
         *
         * @dev:        Device to open
         * @return 0 ok OK, -ve on error
         */
        int (*open)(struct udevice *dev);

        /**
         * close() - Close the current session
         *
         * Releasing the locked locality. Returns 0 on success, -ve 1 on
         * failure (in case lock removal did not succeed).
         *
         * @dev:        Device to close
         * @return 0 ok OK, -ve on error
         */
        int (*close)(struct udevice *dev);

        /**
         * get_desc() - Get a text description of the TPM
         *
         * @dev:        Device to check
         * @buf:        Buffer to put the string
         * @size:       Maximum size of buffer
         * @return length of string, or -ENOSPC it no space
         */
        int (*get_desc)(struct udevice *dev, char *buf, int size);

        /**
         * send() - send data to the TPM
         *
         * @dev:        Device to talk to
         * @sendbuf:    Buffer of the data to send
         * @send_size:  Size of the data to send
         *
         * Returns 0 on success or -ve on failure.
         */
        int (*send)(struct udevice *dev, const u8 *sendbuf, size_t send_size);

        /**
         * recv() - receive a response from the TPM
         *
         * @dev:        Device to talk to
         * @recvbuf:    Buffer to save the response to
         * @max_size:   Maximum number of bytes to receive
         *
         * Returns number of bytes received on success, -EAGAIN if the TPM
         * response is not ready, -EINTR if cancelled, or other -ve value on
         * failure.
         */
        int (*recv)(struct udevice *dev, u8 *recvbuf, size_t max_size);

        /**
         * cleanup() - clean up after an operation in progress
         *
         * This is called if receiving times out. The TPM may need to abort
         * the current transaction if it did not complete, and make itself
         * ready for another.
         *
         * @dev:        Device to talk to
         */
        int (*cleanup)(struct udevice *dev);

        /**
         * xfer() - send data to the TPM and get response
         *
         * This method is optional. If it exists it is used in preference
         * to send(), recv() and cleanup(). It should handle all aspects of
         * TPM communication for a single transfer.
         *
         * @dev:        Device to talk to
         * @sendbuf:    Buffer of the data to send
         * @send_size:  Size of the data to send
         * @recvbuf:    Buffer to save the response to
         * @recv_size:  Pointer to the size of the response buffer
         *
         * Returns 0 on success (and places the number of response bytes at
         * recv_size) or -ve on failure.
         */
        int (*xfer)(struct udevice *dev, const u8 *sendbuf, size_t send_size,
                    u8 *recvbuf, size_t *recv_size);
};

#define tpm_get_ops(dev)        ((struct tpm_ops *)device_get_ops(dev))

#define MAKE_TPM_CMD_ENTRY(cmd) \
        U_BOOT_CMD_MKENT(cmd, 0, 1, do_tpm_ ## cmd, "", "")

#define TPM_COMMAND_NO_ARG(cmd)                         \
int do_##cmd(struct cmd_tbl *cmdtp, int flag,           \
             int argc, char *const argv[])              \
{                                                       \
        struct udevice *dev;                            \
        int rc;                                         \
                                                        \
        rc = get_tpm(&dev);                             \
        if (rc)                                         \
                return rc;                              \
        if (argc != 1)                                  \
                return CMD_RET_USAGE;                   \
        return report_return_code(cmd(dev));            \
}

/**
 * tpm_open() - Request access to locality 0 for the caller
 *
 * After all commands have been completed the caller is supposed to
 * call tpm_close().
 *
 * @dev - TPM device
 * Returns 0 on success, -ve on failure.
 */
int tpm_open(struct udevice *dev);

/**
 * tpm_close() - Close the current session
 *
 * Releasing the locked locality. Returns 0 on success, -ve 1 on
 * failure (in case lock removal did not succeed).
 *
 * @dev - TPM device
 * Returns 0 on success, -ve on failure.
 */
int tpm_close(struct udevice *dev);

/**
 * tpm_clear_and_reenable() - Force clear the TPM and reenable it
 *
 * @dev: TPM device
 * @return 0 on success, -ve on failure
 */
u32 tpm_clear_and_reenable(struct udevice *dev);

/**
 * tpm_get_desc() - Get a text description of the TPM
 *
 * @dev:        Device to check
 * @buf:        Buffer to put the string
 * @size:       Maximum size of buffer
 * @return length of string, or -ENOSPC it no space
 */
int tpm_get_desc(struct udevice *dev, char *buf, int size);

/**
 * tpm_xfer() - send data to the TPM and get response
 *
 * This first uses the device's send() method to send the bytes. Then it calls
 * recv() to get the reply. If recv() returns -EAGAIN then it will delay a
 * short time and then call recv() again.
 *
 * Regardless of whether recv() completes successfully, it will then call
 * cleanup() to finish the transaction.
 *
 * Note that the outgoing data is inspected to determine command type
 * (ordinal) and a timeout is used for that command type.
 *
 * @dev - TPM device
 * @sendbuf - buffer of the data to send
 * @send_size size of the data to send
 * @recvbuf - memory to save the response to
 * @recv_len - pointer to the size of the response buffer
 *
 * Returns 0 on success (and places the number of response bytes at
 * recv_len) or -ve on failure.
 */
int tpm_xfer(struct udevice *dev, const u8 *sendbuf, size_t send_size,
             u8 *recvbuf, size_t *recv_size);

/**
 * Initialize TPM device.  It must be called before any TPM commands.
 *
 * @dev - TPM device
 * @return 0 on success, non-0 on error.
 */
int tpm_init(struct udevice *dev);

/**
 * Retrieve the array containing all the v1 (resp. v2) commands.
 *
 * @return a struct cmd_tbl array.
 */
#if defined(CONFIG_TPM_V1)
struct cmd_tbl *get_tpm1_commands(unsigned int *size);
#else
static inline struct cmd_tbl *get_tpm1_commands(unsigned int *size)
{
        return NULL;
}
#endif
#if defined(CONFIG_TPM_V2)
struct cmd_tbl *get_tpm2_commands(unsigned int *size);
#else
static inline struct cmd_tbl *get_tpm2_commands(unsigned int *size)
{
        return NULL;
}
#endif

/**
 * tpm_get_version() - Find the version of a TPM
 *
 * This checks the uclass data for a TPM device and returns the version number
 * it supports.
 *
 * @dev: TPM device
 * @return version number (TPM_V1 or TPMV2)
 */
enum tpm_version tpm_get_version(struct udevice *dev);

/* Iterate on all TPM devices */
#define for_each_tpm_device(dev) uclass_foreach_dev_probe(UCLASS_TPM, (dev))

#endif /* __TPM_COMMON_H */