root/drivers/crypto/ccp/dbc.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * AMD Secure Processor Dynamic Boost Control interface
 *
 * Copyright (C) 2023 Advanced Micro Devices, Inc.
 *
 * Author: Mario Limonciello <mario.limonciello@amd.com>
 */

#include <linux/mutex.h>

#include "dbc.h"

#define DBC_DEFAULT_TIMEOUT             (10 * MSEC_PER_SEC)
struct error_map {
        u32 psp;
        int ret;
};

#define DBC_ERROR_ACCESS_DENIED         0x0001
#define DBC_ERROR_EXCESS_DATA           0x0004
#define DBC_ERROR_BAD_PARAMETERS        0x0006
#define DBC_ERROR_BAD_STATE             0x0007
#define DBC_ERROR_NOT_IMPLEMENTED       0x0009
#define DBC_ERROR_BUSY                  0x000D
#define DBC_ERROR_MESSAGE_FAILURE       0x0307
#define DBC_ERROR_OVERFLOW              0x300F
#define DBC_ERROR_SIGNATURE_INVALID     0x3072

static struct error_map error_codes[] = {
        {DBC_ERROR_ACCESS_DENIED,       -EACCES},
        {DBC_ERROR_EXCESS_DATA,         -E2BIG},
        {DBC_ERROR_BAD_PARAMETERS,      -EINVAL},
        {DBC_ERROR_BAD_STATE,           -EAGAIN},
        {DBC_ERROR_MESSAGE_FAILURE,     -ENOENT},
        {DBC_ERROR_NOT_IMPLEMENTED,     -ENOENT},
        {DBC_ERROR_BUSY,                -EBUSY},
        {DBC_ERROR_OVERFLOW,            -ENFILE},
        {DBC_ERROR_SIGNATURE_INVALID,   -EPERM},
        {0x0,   0x0},
};

static inline int send_dbc_cmd_thru_ext(struct psp_dbc_device *dbc_dev, int msg)
{
        dbc_dev->mbox->ext_req.header.sub_cmd_id = msg;

        return psp_extended_mailbox_cmd(dbc_dev->psp,
                                        DBC_DEFAULT_TIMEOUT,
                                        (struct psp_ext_request *)dbc_dev->mbox);
}

static inline int send_dbc_cmd_thru_pa(struct psp_dbc_device *dbc_dev, int msg)
{
        return psp_send_platform_access_msg(msg,
                                            (struct psp_request *)dbc_dev->mbox);
}

static int send_dbc_cmd(struct psp_dbc_device *dbc_dev, int msg)
{
        int ret;

        *dbc_dev->result = 0;
        ret = dbc_dev->use_ext ? send_dbc_cmd_thru_ext(dbc_dev, msg) :
                                 send_dbc_cmd_thru_pa(dbc_dev, msg);
        if (ret == -EIO) {
                int i;

                dev_dbg(dbc_dev->dev,
                         "msg 0x%x failed with PSP error: 0x%x\n",
                         msg, *dbc_dev->result);

                for (i = 0; error_codes[i].psp; i++) {
                        if (*dbc_dev->result == error_codes[i].psp)
                                return error_codes[i].ret;
                }
        }

        return ret;
}

static int send_dbc_nonce(struct psp_dbc_device *dbc_dev)
{
        int ret;

        *dbc_dev->payload_size = dbc_dev->header_size + sizeof(struct dbc_user_nonce);
        ret = send_dbc_cmd(dbc_dev, PSP_DYNAMIC_BOOST_GET_NONCE);
        if (ret == -EAGAIN) {
                dev_dbg(dbc_dev->dev, "retrying get nonce\n");
                ret = send_dbc_cmd(dbc_dev, PSP_DYNAMIC_BOOST_GET_NONCE);
        }

        return ret;
}

static int send_dbc_parameter(struct psp_dbc_device *dbc_dev)
{
        struct dbc_user_param *user_param = (struct dbc_user_param *)dbc_dev->payload;

        switch (user_param->msg_index) {
        case PARAM_SET_FMAX_CAP:
        case PARAM_SET_PWR_CAP:
        case PARAM_SET_GFX_MODE:
                return send_dbc_cmd(dbc_dev, PSP_DYNAMIC_BOOST_SET_PARAMETER);
        case PARAM_GET_FMAX_CAP:
        case PARAM_GET_PWR_CAP:
        case PARAM_GET_CURR_TEMP:
        case PARAM_GET_FMAX_MAX:
        case PARAM_GET_FMAX_MIN:
        case PARAM_GET_SOC_PWR_MAX:
        case PARAM_GET_SOC_PWR_MIN:
        case PARAM_GET_SOC_PWR_CUR:
        case PARAM_GET_GFX_MODE:
                return send_dbc_cmd(dbc_dev, PSP_DYNAMIC_BOOST_GET_PARAMETER);
        }

        return -EINVAL;
}

void dbc_dev_destroy(struct psp_device *psp)
{
        struct psp_dbc_device *dbc_dev = psp->dbc_data;

        if (!dbc_dev)
                return;

        misc_deregister(&dbc_dev->char_dev);
        mutex_destroy(&dbc_dev->ioctl_mutex);
        psp->dbc_data = NULL;
}

static long dbc_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
        struct psp_device *psp_master = psp_get_master_device();
        void __user *argp = (void __user *)arg;
        struct psp_dbc_device *dbc_dev;
        int ret;

        if (!psp_master || !psp_master->dbc_data)
                return -ENODEV;
        dbc_dev = psp_master->dbc_data;

        guard(mutex)(&dbc_dev->ioctl_mutex);

        switch (cmd) {
        case DBCIOCNONCE:
                if (copy_from_user(dbc_dev->payload, argp, sizeof(struct dbc_user_nonce)))
                        return -EFAULT;

                ret = send_dbc_nonce(dbc_dev);
                if (ret)
                        return ret;

                if (copy_to_user(argp, dbc_dev->payload, sizeof(struct dbc_user_nonce)))
                        return -EFAULT;
                break;
        case DBCIOCUID:
                if (copy_from_user(dbc_dev->payload, argp, sizeof(struct dbc_user_setuid)))
                        return -EFAULT;

                *dbc_dev->payload_size = dbc_dev->header_size + sizeof(struct dbc_user_setuid);
                ret = send_dbc_cmd(dbc_dev, PSP_DYNAMIC_BOOST_SET_UID);
                if (ret)
                        return ret;

                if (copy_to_user(argp, dbc_dev->payload, sizeof(struct dbc_user_setuid)))
                        return -EFAULT;
                break;
        case DBCIOCPARAM:
                if (copy_from_user(dbc_dev->payload, argp, sizeof(struct dbc_user_param)))
                        return -EFAULT;

                *dbc_dev->payload_size = dbc_dev->header_size + sizeof(struct dbc_user_param);
                ret = send_dbc_parameter(dbc_dev);
                if (ret)
                        return ret;

                if (copy_to_user(argp, dbc_dev->payload, sizeof(struct dbc_user_param)))
                        return -EFAULT;
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static const struct file_operations dbc_fops = {
        .owner  = THIS_MODULE,
        .unlocked_ioctl = dbc_ioctl,
};

int dbc_dev_init(struct psp_device *psp)
{
        struct device *dev = psp->dev;
        struct psp_dbc_device *dbc_dev;
        int ret;

        dbc_dev = devm_kzalloc(dev, sizeof(*dbc_dev), GFP_KERNEL);
        if (!dbc_dev)
                return -ENOMEM;

        BUILD_BUG_ON(sizeof(union dbc_buffer) > PAGE_SIZE);
        dbc_dev->mbox = (void *)devm_get_free_pages(dev, GFP_KERNEL | __GFP_ZERO, 0);
        if (!dbc_dev->mbox) {
                ret = -ENOMEM;
                goto cleanup_dev;
        }

        psp->dbc_data = dbc_dev;
        dbc_dev->dev = dev;
        dbc_dev->psp = psp;

        if (psp->capability.dbc_thru_ext) {
                dbc_dev->use_ext = true;
                dbc_dev->payload_size = &dbc_dev->mbox->ext_req.header.payload_size;
                dbc_dev->result = &dbc_dev->mbox->ext_req.header.status;
                dbc_dev->payload = &dbc_dev->mbox->ext_req.buf;
                dbc_dev->header_size = sizeof(struct psp_ext_req_buffer_hdr);
        } else {
                dbc_dev->payload_size = &dbc_dev->mbox->pa_req.header.payload_size;
                dbc_dev->result = &dbc_dev->mbox->pa_req.header.status;
                dbc_dev->payload = &dbc_dev->mbox->pa_req.buf;
                dbc_dev->header_size = sizeof(struct psp_req_buffer_hdr);
        }

        ret = send_dbc_nonce(dbc_dev);
        if (ret == -EACCES) {
                dev_dbg(dbc_dev->dev,
                        "dynamic boost control was previously authenticated\n");
                ret = 0;
        }
        dev_dbg(dbc_dev->dev, "dynamic boost control is %savailable\n",
                ret ? "un" : "");
        if (ret) {
                ret = 0;
                goto cleanup_mbox;
        }

        dbc_dev->char_dev.minor = MISC_DYNAMIC_MINOR;
        dbc_dev->char_dev.name = "dbc";
        dbc_dev->char_dev.fops = &dbc_fops;
        dbc_dev->char_dev.mode = 0600;
        ret = misc_register(&dbc_dev->char_dev);
        if (ret)
                goto cleanup_mbox;

        mutex_init(&dbc_dev->ioctl_mutex);

        return 0;

cleanup_mbox:
        devm_free_pages(dev, (unsigned long)dbc_dev->mbox);

cleanup_dev:
        psp->dbc_data = NULL;
        devm_kfree(dev, dbc_dev);

        return ret;
}