// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012-2014 Intel Corporation
 *
 * Authors:
 * Xiaoyan Zhang <xiaoyan.zhang@intel.com>
 * Jiang Liu <jiang.liu@linux.intel.com>
 * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
 *
 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
 *
 * This file contains implementation of the sysfs interface for PPI.
 */


#include <linux/acpi.h>
#include "tpm.h"

#define TPM_PPI_REVISION_ID_1   1
#define TPM_PPI_REVISION_ID_2   2
#define TPM_PPI_FN_VERSION      1
#define TPM_PPI_FN_SUBREQ       2
#define TPM_PPI_FN_GETREQ       3
#define TPM_PPI_FN_GETACT       4
#define TPM_PPI_FN_GETRSP       5
#define TPM_PPI_FN_SUBREQ2      7
#define TPM_PPI_FN_GETOPR       8
#define PPI_TPM_REQ_MAX         101 /* PPI 1.3 for TPM 2 */
#define PPI_VS_REQ_START        128
#define PPI_VS_REQ_END          255

static const guid_t tpm_ppi_guid =
        GUID_INIT(0x3DDDFAA6, 0x361B, 0x4EB4,
                  0xA4, 0x24, 0x8D, 0x10, 0x08, 0x9D, 0x16, 0x53);

static const char * const tpm_ppi_info[] = {
        "Not implemented",
        "BIOS only",
        "Blocked for OS by system firmware",
        "User required",
        "User not required",
};

/* A spinlock to protect access to the cache from concurrent reads */
static DEFINE_MUTEX(tpm_ppi_lock);

static u32 ppi_operations_cache[PPI_VS_REQ_END + 1];
static bool ppi_cache_populated;

static bool tpm_ppi_req_has_parameter(u64 req)
{
        return req == 23;
}

static inline union acpi_object *
tpm_eval_dsm(acpi_handle ppi_handle, int func, acpi_object_type type,
             union acpi_object *argv4, u64 rev)
{
        BUG_ON(!ppi_handle);
        return acpi_evaluate_dsm_typed(ppi_handle, &tpm_ppi_guid,
                                       rev, func, argv4, type);
}

static ssize_t tpm_show_ppi_version(struct device *dev,
                                    struct device_attribute *attr, char *buf)
{
        struct tpm_chip *chip = to_tpm_chip(dev);

        return sysfs_emit(buf, "%s\n", chip->ppi_version);
}

static ssize_t tpm_show_ppi_request(struct device *dev,
                                    struct device_attribute *attr, char *buf)
{
        ssize_t size = -EINVAL;
        union acpi_object *obj;
        struct tpm_chip *chip = to_tpm_chip(dev);
        u64 rev = TPM_PPI_REVISION_ID_2;
        u64 req;

        if (strcmp(chip->ppi_version, "1.2") < 0)
                rev = TPM_PPI_REVISION_ID_1;

        obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETREQ,
                           ACPI_TYPE_PACKAGE, NULL, rev);
        if (!obj)
                return -ENXIO;

        /*
         * output.pointer should be of package type, including two integers.
         * The first is function return code, 0 means success and 1 means
         * error. The second is pending TPM operation requested by the OS, 0
         * means none and >0 means operation value.
         */
        if (obj->package.count == 3 &&
            obj->package.elements[0].type == ACPI_TYPE_INTEGER &&
            obj->package.elements[1].type == ACPI_TYPE_INTEGER &&
            obj->package.elements[2].type == ACPI_TYPE_INTEGER) {
                if (obj->package.elements[0].integer.value)
                        size = -EFAULT;
                else {
                        req = obj->package.elements[1].integer.value;
                        if (tpm_ppi_req_has_parameter(req))
                                size = sysfs_emit(buf, "%llu %llu\n", req,
                                                  obj->package.elements[2].integer.value);
                        else
                                size = sysfs_emit(buf, "%llu\n", req);
                }
        } else if (obj->package.count == 2 &&
            obj->package.elements[0].type == ACPI_TYPE_INTEGER &&
            obj->package.elements[1].type == ACPI_TYPE_INTEGER) {
                if (obj->package.elements[0].integer.value)
                        size = -EFAULT;
                else
                        size = sysfs_emit(buf, "%llu\n",
                                          obj->package.elements[1].integer.value);
        }

        ACPI_FREE(obj);

        return size;
}

static ssize_t tpm_store_ppi_request(struct device *dev,
                                     struct device_attribute *attr,
                                     const char *buf, size_t count)
{
        u32 req;
        u64 ret;
        int func = TPM_PPI_FN_SUBREQ;
        union acpi_object *obj, tmp[2];
        union acpi_object argv4 = ACPI_INIT_DSM_ARGV4(2, tmp);
        struct tpm_chip *chip = to_tpm_chip(dev);
        u64 rev = TPM_PPI_REVISION_ID_1;

        /*
         * the function to submit TPM operation request to pre-os environment
         * is updated with function index from SUBREQ to SUBREQ2 since PPI
         * version 1.1
         */
        if (acpi_check_dsm(chip->acpi_dev_handle, &tpm_ppi_guid,
                           TPM_PPI_REVISION_ID_1, 1 << TPM_PPI_FN_SUBREQ2))
                func = TPM_PPI_FN_SUBREQ2;

        /*
         * PPI spec defines params[3].type as ACPI_TYPE_PACKAGE. Some BIOS
         * accept buffer/string/integer type, but some BIOS accept buffer/
         * string/package type. For PPI version 1.0 and 1.1, use buffer type
         * for compatibility, and use package type since 1.2 according to spec.
         */
        if (strcmp(chip->ppi_version, "1.3") == 0) {
                if (sscanf(buf, "%llu %llu", &tmp[0].integer.value,
                           &tmp[1].integer.value) != 2)
                        goto ppi12;
                rev = TPM_PPI_REVISION_ID_2;
                tmp[0].type = ACPI_TYPE_INTEGER;
                tmp[1].type = ACPI_TYPE_INTEGER;
        } else if (strcmp(chip->ppi_version, "1.2") < 0) {
                if (sscanf(buf, "%d", &req) != 1)
                        return -EINVAL;
                argv4.type = ACPI_TYPE_BUFFER;
                argv4.buffer.length = sizeof(req);
                argv4.buffer.pointer = (u8 *)&req;
        } else {
ppi12:
                argv4.package.count = 1;
                tmp[0].type = ACPI_TYPE_INTEGER;
                if (sscanf(buf, "%llu", &tmp[0].integer.value) != 1)
                        return -EINVAL;
        }

        obj = tpm_eval_dsm(chip->acpi_dev_handle, func, ACPI_TYPE_INTEGER,
                           &argv4, rev);
        if (!obj) {
                return -ENXIO;
        } else {
                ret = obj->integer.value;
                ACPI_FREE(obj);
        }

        if (ret == 0)
                return (acpi_status)count;

        return (ret == 1) ? -EPERM : -EFAULT;
}

static ssize_t tpm_show_ppi_transition_action(struct device *dev,
                                              struct device_attribute *attr,
                                              char *buf)
{
        u32 ret;
        acpi_status status;
        union acpi_object *obj = NULL;
        union acpi_object tmp = {
                .buffer.type = ACPI_TYPE_BUFFER,
                .buffer.length = 0,
                .buffer.pointer = NULL
        };
        struct tpm_chip *chip = to_tpm_chip(dev);

        static char *info[] = {
                "None",
                "Shutdown",
                "Reboot",
                "OS Vendor-specific",
                "Error",
        };

        /*
         * PPI spec defines params[3].type as empty package, but some platforms
         * (e.g. Capella with PPI 1.0) need integer/string/buffer type, so for
         * compatibility, define params[3].type as buffer, if PPI version < 1.2
         */
        if (strcmp(chip->ppi_version, "1.2") < 0)
                obj = &tmp;
        obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETACT,
                           ACPI_TYPE_INTEGER, obj, TPM_PPI_REVISION_ID_1);
        if (!obj) {
                return -ENXIO;
        } else {
                ret = obj->integer.value;
                ACPI_FREE(obj);
        }

        if (ret < ARRAY_SIZE(info) - 1)
                status = sysfs_emit(buf, "%d: %s\n", ret, info[ret]);
        else
                status = sysfs_emit(buf, "%d: %s\n", ret,
                                    info[ARRAY_SIZE(info) - 1]);
        return status;
}

static ssize_t tpm_show_ppi_response(struct device *dev,
                                     struct device_attribute *attr,
                                     char *buf)
{
        acpi_status status = -EINVAL;
        union acpi_object *obj, *ret_obj;
        u64 req, res;
        struct tpm_chip *chip = to_tpm_chip(dev);

        obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETRSP,
                           ACPI_TYPE_PACKAGE, NULL, TPM_PPI_REVISION_ID_1);
        if (!obj)
                return -ENXIO;

        /*
         * parameter output.pointer should be of package type, including
         * 3 integers. The first means function return code, the second means
         * most recent TPM operation request, and the last means response to
         * the most recent TPM operation request. Only if the first is 0, and
         * the second integer is not 0, the response makes sense.
         */
        ret_obj = obj->package.elements;
        if (obj->package.count < 3 ||
            ret_obj[0].type != ACPI_TYPE_INTEGER ||
            ret_obj[1].type != ACPI_TYPE_INTEGER ||
            ret_obj[2].type != ACPI_TYPE_INTEGER)
                goto cleanup;

        if (ret_obj[0].integer.value) {
                status = -EFAULT;
                goto cleanup;
        }

        req = ret_obj[1].integer.value;
        res = ret_obj[2].integer.value;
        if (req) {
                if (res == 0)
                        status = sysfs_emit(buf, "%llu %s\n", req,
                                            "0: Success");
                else if (res == 0xFFFFFFF0)
                        status = sysfs_emit(buf, "%llu %s\n", req,
                                            "0xFFFFFFF0: User Abort");
                else if (res == 0xFFFFFFF1)
                        status = sysfs_emit(buf, "%llu %s\n", req,
                                            "0xFFFFFFF1: BIOS Failure");
                else if (res >= 1 && res <= 0x00000FFF)
                        status = sysfs_emit(buf, "%llu %llu: %s\n",
                                            req, res, "Corresponding TPM error");
                else
                        status = sysfs_emit(buf, "%llu %llu: %s\n",
                                            req, res, "Error");
        } else {
                status = sysfs_emit(buf, "%llu: %s\n",
                                    req, "No Recent Request");
        }

cleanup:
        ACPI_FREE(obj);
        return status;
}

static ssize_t cache_ppi_operations(acpi_handle dev_handle, char *buf)
{
        int i;
        u32 ret;
        int len = 0;
        union acpi_object *obj, tmp;
        union acpi_object argv = ACPI_INIT_DSM_ARGV4(1, &tmp);

        if (!acpi_check_dsm(dev_handle, &tpm_ppi_guid, TPM_PPI_REVISION_ID_1,
                            1 << TPM_PPI_FN_GETOPR))
                return -EPERM;

        tmp.integer.type = ACPI_TYPE_INTEGER;
        for (i = 0; i <= PPI_VS_REQ_END; i++) {
                tmp.integer.value = i;
                obj = tpm_eval_dsm(dev_handle, TPM_PPI_FN_GETOPR,
                                   ACPI_TYPE_INTEGER, &argv,
                                   TPM_PPI_REVISION_ID_1);
                if (!obj)
                        return -ENOMEM;

                ret = obj->integer.value;
                ppi_operations_cache[i] = ret;
                ACPI_FREE(obj);
        }

        return len;
}

static ssize_t tpm_show_ppi_tcg_operations(struct device *dev,
                                           struct device_attribute *attr,
                                           char *buf)
{
        struct tpm_chip *chip = to_tpm_chip(dev);
        ssize_t len = 0;
        u32 ret;
        int i;

        mutex_lock(&tpm_ppi_lock);
        if (!ppi_cache_populated) {
                len = cache_ppi_operations(chip->acpi_dev_handle, buf);
                if (len < 0) {
                        mutex_unlock(&tpm_ppi_lock);
                        return len;
                }

                ppi_cache_populated = true;
        }

        for (i = 0; i <= PPI_TPM_REQ_MAX; i++) {
                ret = ppi_operations_cache[i];
                if (ret >= 0 && ret < ARRAY_SIZE(tpm_ppi_info))
                        len += sysfs_emit_at(buf, len, "%d %d: %s\n",
                                                        i, ret, tpm_ppi_info[ret]);
        }
        mutex_unlock(&tpm_ppi_lock);

        return len;
}

static ssize_t tpm_show_ppi_vs_operations(struct device *dev,
                                          struct device_attribute *attr,
                                          char *buf)
{
        struct tpm_chip *chip = to_tpm_chip(dev);
        ssize_t len = 0;
        u32 ret;
        int i;

        mutex_lock(&tpm_ppi_lock);
        if (!ppi_cache_populated) {
                len = cache_ppi_operations(chip->acpi_dev_handle, buf);
                if (len < 0) {
                        mutex_unlock(&tpm_ppi_lock);
                        return len;
                }

                ppi_cache_populated = true;
        }

        for (i = PPI_VS_REQ_START; i <= PPI_VS_REQ_END; i++) {
                ret = ppi_operations_cache[i];
                if (ret >= 0 && ret < ARRAY_SIZE(tpm_ppi_info))
                        len += sysfs_emit_at(buf, len, "%d %d: %s\n",
                                                        i, ret, tpm_ppi_info[ret]);
        }
        mutex_unlock(&tpm_ppi_lock);

        return len;
}

static DEVICE_ATTR(version, S_IRUGO, tpm_show_ppi_version, NULL);
static DEVICE_ATTR(request, S_IRUGO | S_IWUSR | S_IWGRP,
                   tpm_show_ppi_request, tpm_store_ppi_request);
static DEVICE_ATTR(transition_action, S_IRUGO,
                   tpm_show_ppi_transition_action, NULL);
static DEVICE_ATTR(response, S_IRUGO, tpm_show_ppi_response, NULL);
static DEVICE_ATTR(tcg_operations, S_IRUGO, tpm_show_ppi_tcg_operations, NULL);
static DEVICE_ATTR(vs_operations, S_IRUGO, tpm_show_ppi_vs_operations, NULL);

static struct attribute *ppi_attrs[] = {
        &dev_attr_version.attr,
        &dev_attr_request.attr,
        &dev_attr_transition_action.attr,
        &dev_attr_response.attr,
        &dev_attr_tcg_operations.attr,
        &dev_attr_vs_operations.attr, NULL,
};
static const struct attribute_group ppi_attr_grp = {
        .name = "ppi",
        .attrs = ppi_attrs
};

void tpm_add_ppi(struct tpm_chip *chip)
{
        union acpi_object *obj;

        if (!chip->acpi_dev_handle)
                return;

        if (!acpi_check_dsm(chip->acpi_dev_handle, &tpm_ppi_guid,
                            TPM_PPI_REVISION_ID_1, 1 << TPM_PPI_FN_VERSION))
                return;

        /* Cache PPI version string. */
        obj = acpi_evaluate_dsm_typed(chip->acpi_dev_handle, &tpm_ppi_guid,
                                      TPM_PPI_REVISION_ID_1,
                                      TPM_PPI_FN_VERSION,
                                      NULL, ACPI_TYPE_STRING);
        if (obj) {
                strscpy(chip->ppi_version, obj->string.pointer,
                        sizeof(chip->ppi_version));
                ACPI_FREE(obj);
        }

        chip->groups[chip->groups_cnt++] = &ppi_attr_grp;
}