// SPDX-License-Identifier: GPL-2.0
/*
 * Management-Controller-to-Driver Interface
 *
 * Copyright 2008-2013 Solarflare Communications Inc.
 * Copyright (C) 2022-2023, Advanced Micro Devices, Inc.
 */
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/if_vlan.h>
#include <linux/timer.h>
#include <linux/list.h>
#include <linux/pci.h>
#include <linux/device.h>
#include <linux/rwsem.h>
#include <linux/vmalloc.h>
#include <net/netevent.h>
#include <linux/log2.h>
#include <linux/net_tstamp.h>
#include <linux/wait.h>
#include <linux/cdx/bitfield.h>

#include <linux/cdx/mcdi.h>
#include "mcdid.h"

static void cdx_mcdi_cancel_cmd(struct cdx_mcdi *cdx, struct cdx_mcdi_cmd *cmd);
static void cdx_mcdi_wait_for_cleanup(struct cdx_mcdi *cdx);
static int cdx_mcdi_rpc_async_internal(struct cdx_mcdi *cdx,
                                       struct cdx_mcdi_cmd *cmd,
                                       unsigned int *handle);
static void cdx_mcdi_start_or_queue(struct cdx_mcdi_iface *mcdi,
                                    bool allow_retry);
static void cdx_mcdi_cmd_start_or_queue(struct cdx_mcdi_iface *mcdi,
                                        struct cdx_mcdi_cmd *cmd);
static bool cdx_mcdi_complete_cmd(struct cdx_mcdi_iface *mcdi,
                                  struct cdx_mcdi_cmd *cmd,
                                  struct cdx_dword *outbuf,
                                  int len,
                                  struct list_head *cleanup_list);
static void cdx_mcdi_timeout_cmd(struct cdx_mcdi_iface *mcdi,
                                 struct cdx_mcdi_cmd *cmd,
                                 struct list_head *cleanup_list);
static void cdx_mcdi_cmd_work(struct work_struct *context);
static void cdx_mcdi_mode_fail(struct cdx_mcdi *cdx, struct list_head *cleanup_list);
static void _cdx_mcdi_display_error(struct cdx_mcdi *cdx, unsigned int cmd,
                                    size_t inlen, int raw, int arg, int err_no);

static bool cdx_cmd_cancelled(struct cdx_mcdi_cmd *cmd)
{
        return cmd->state == MCDI_STATE_RUNNING_CANCELLED;
}

static void cdx_mcdi_cmd_release(struct kref *ref)
{
        kfree(container_of(ref, struct cdx_mcdi_cmd, ref));
}

static unsigned int cdx_mcdi_cmd_handle(struct cdx_mcdi_cmd *cmd)
{
        return cmd->handle;
}

static void _cdx_mcdi_remove_cmd(struct cdx_mcdi_iface *mcdi,
                                 struct cdx_mcdi_cmd *cmd,
                                 struct list_head *cleanup_list)
{
        /* if cancelled, the completers have already been called */
        if (cdx_cmd_cancelled(cmd))
                return;

        if (cmd->completer) {
                list_add_tail(&cmd->cleanup_list, cleanup_list);
                ++mcdi->outstanding_cleanups;
                kref_get(&cmd->ref);
        }
}

static void cdx_mcdi_remove_cmd(struct cdx_mcdi_iface *mcdi,
                                struct cdx_mcdi_cmd *cmd,
                                struct list_head *cleanup_list)
{
        list_del(&cmd->list);
        _cdx_mcdi_remove_cmd(mcdi, cmd, cleanup_list);
        cmd->state = MCDI_STATE_FINISHED;
        kref_put(&cmd->ref, cdx_mcdi_cmd_release);
        if (list_empty(&mcdi->cmd_list))
                wake_up(&mcdi->cmd_complete_wq);
}

static unsigned long cdx_mcdi_rpc_timeout(struct cdx_mcdi *cdx, unsigned int cmd)
{
        if (!cdx->mcdi_ops->mcdi_rpc_timeout)
                return MCDI_RPC_TIMEOUT;
        else
                return cdx->mcdi_ops->mcdi_rpc_timeout(cdx, cmd);
}

/**
 * cdx_mcdi_init - Initialize MCDI (Management Controller Driver Interface) state
 * @cdx:        Handle to the CDX MCDI structure
 *
 * This function allocates and initializes internal MCDI structures and resources
 * for the CDX device, including the workqueue, locking primitives, and command
 * tracking mechanisms. It sets the initial operating mode and prepares the device
 * for MCDI operations.
 *
 * Return:
 * * 0        - on success
 * * -ENOMEM  - if memory allocation or workqueue creation fails
 */
int cdx_mcdi_init(struct cdx_mcdi *cdx)
{
        struct cdx_mcdi_iface *mcdi;
        int rc = -ENOMEM;

        cdx->mcdi = kzalloc_obj(*cdx->mcdi);
        if (!cdx->mcdi)
                goto fail;

        mcdi = cdx_mcdi_if(cdx);
        mcdi->cdx = cdx;

        mcdi->workqueue = alloc_ordered_workqueue("mcdi_wq", 0);
        if (!mcdi->workqueue)
                goto fail2;
        mutex_init(&mcdi->iface_lock);
        mcdi->mode = MCDI_MODE_EVENTS;
        INIT_LIST_HEAD(&mcdi->cmd_list);
        init_waitqueue_head(&mcdi->cmd_complete_wq);

        mcdi->new_epoch = true;

        return 0;
fail2:
        kfree(cdx->mcdi);
        cdx->mcdi = NULL;
fail:
        return rc;
}
EXPORT_SYMBOL_GPL(cdx_mcdi_init);

/**
 * cdx_mcdi_finish - Cleanup MCDI (Management Controller Driver Interface) state
 * @cdx:        Handle to the CDX MCDI structure
 *
 * This function is responsible for cleaning up the MCDI (Management Controller Driver Interface)
 * resources associated with a cdx_mcdi structure. Also destroys the mcdi workqueue.
 *
 */
void cdx_mcdi_finish(struct cdx_mcdi *cdx)
{
        struct cdx_mcdi_iface *mcdi;

        mcdi = cdx_mcdi_if(cdx);
        if (!mcdi)
                return;

        cdx_mcdi_wait_for_cleanup(cdx);

        destroy_workqueue(mcdi->workqueue);
        kfree(cdx->mcdi);
        cdx->mcdi = NULL;
}
EXPORT_SYMBOL_GPL(cdx_mcdi_finish);

static bool cdx_mcdi_flushed(struct cdx_mcdi_iface *mcdi, bool ignore_cleanups)
{
        bool flushed;

        mutex_lock(&mcdi->iface_lock);
        flushed = list_empty(&mcdi->cmd_list) &&
                  (ignore_cleanups || !mcdi->outstanding_cleanups);
        mutex_unlock(&mcdi->iface_lock);
        return flushed;
}

/* Wait for outstanding MCDI commands to complete. */
static void cdx_mcdi_wait_for_cleanup(struct cdx_mcdi *cdx)
{
        struct cdx_mcdi_iface *mcdi = cdx_mcdi_if(cdx);

        if (!mcdi)
                return;

        wait_event(mcdi->cmd_complete_wq,
                   cdx_mcdi_flushed(mcdi, false));
}

int cdx_mcdi_wait_for_quiescence(struct cdx_mcdi *cdx,
                                 unsigned int timeout_jiffies)
{
        struct cdx_mcdi_iface *mcdi = cdx_mcdi_if(cdx);
        DEFINE_WAIT_FUNC(wait, woken_wake_function);
        int rc = 0;

        if (!mcdi)
                return -EINVAL;

        flush_workqueue(mcdi->workqueue);

        add_wait_queue(&mcdi->cmd_complete_wq, &wait);

        while (!cdx_mcdi_flushed(mcdi, true)) {
                rc = wait_woken(&wait, TASK_IDLE, timeout_jiffies);
                if (rc)
                        continue;
                break;
        }

        remove_wait_queue(&mcdi->cmd_complete_wq, &wait);

        if (rc > 0)
                rc = 0;
        else if (rc == 0)
                rc = -ETIMEDOUT;

        return rc;
}

static u8 cdx_mcdi_payload_csum(const struct cdx_dword *hdr, size_t hdr_len,
                                const struct cdx_dword *sdu, size_t sdu_len)
{
        u8 *p = (u8 *)hdr;
        u8 csum = 0;
        int i;

        for (i = 0; i < hdr_len; i++)
                csum += p[i];

        p = (u8 *)sdu;
        for (i = 0; i < sdu_len; i++)
                csum += p[i];

        return ~csum & 0xff;
}

static void cdx_mcdi_send_request(struct cdx_mcdi *cdx,
                                  struct cdx_mcdi_cmd *cmd)
{
        struct cdx_mcdi_iface *mcdi = cdx_mcdi_if(cdx);
        const struct cdx_dword *inbuf = cmd->inbuf;
        size_t inlen = cmd->inlen;
        struct cdx_dword hdr[2];
        size_t hdr_len;
        bool not_epoch;
        u32 xflags;

        if (!mcdi)
                return;

        mcdi->prev_seq = cmd->seq;
        mcdi->seq_held_by[cmd->seq] = cmd;
        mcdi->db_held_by = cmd;
        cmd->started = jiffies;

        not_epoch = !mcdi->new_epoch;
        xflags = 0;

        /* MCDI v2 */
        WARN_ON(inlen > MCDI_CTL_SDU_LEN_MAX_V2);
        CDX_POPULATE_DWORD_7(hdr[0],
                             MCDI_HEADER_RESPONSE, 0,
                             MCDI_HEADER_RESYNC, 1,
                             MCDI_HEADER_CODE, MC_CMD_V2_EXTN,
                             MCDI_HEADER_DATALEN, 0,
                             MCDI_HEADER_SEQ, cmd->seq,
                             MCDI_HEADER_XFLAGS, xflags,
                             MCDI_HEADER_NOT_EPOCH, not_epoch);
        CDX_POPULATE_DWORD_3(hdr[1],
                             MC_CMD_V2_EXTN_IN_EXTENDED_CMD, cmd->cmd,
                             MC_CMD_V2_EXTN_IN_ACTUAL_LEN, inlen,
                             MC_CMD_V2_EXTN_IN_MESSAGE_TYPE,
                             MC_CMD_V2_EXTN_IN_MCDI_MESSAGE_TYPE_PLATFORM);
        hdr_len = 8;

        hdr[0].cdx_u32 |= (__force __le32)(cdx_mcdi_payload_csum(hdr, hdr_len, inbuf, inlen) <<
                         MCDI_HEADER_XFLAGS_LBN);

        print_hex_dump_debug("MCDI REQ HEADER: ", DUMP_PREFIX_NONE, 32, 4, hdr, hdr_len, false);
        print_hex_dump_debug("MCDI REQ PAYLOAD: ", DUMP_PREFIX_NONE, 32, 4, inbuf, inlen, false);

        cdx->mcdi_ops->mcdi_request(cdx, hdr, hdr_len, inbuf, inlen);

        mcdi->new_epoch = false;
}

static int cdx_mcdi_errno(struct cdx_mcdi *cdx, unsigned int mcdi_err)
{
        switch (mcdi_err) {
        case 0:
        case MC_CMD_ERR_QUEUE_FULL:
                return mcdi_err;
        case MC_CMD_ERR_EPERM:
                return -EPERM;
        case MC_CMD_ERR_ENOENT:
                return -ENOENT;
        case MC_CMD_ERR_EINTR:
                return -EINTR;
        case MC_CMD_ERR_EAGAIN:
                return -EAGAIN;
        case MC_CMD_ERR_EACCES:
                return -EACCES;
        case MC_CMD_ERR_EBUSY:
                return -EBUSY;
        case MC_CMD_ERR_EINVAL:
                return -EINVAL;
        case MC_CMD_ERR_ERANGE:
                return -ERANGE;
        case MC_CMD_ERR_EDEADLK:
                return -EDEADLK;
        case MC_CMD_ERR_ENOSYS:
                return -EOPNOTSUPP;
        case MC_CMD_ERR_ETIME:
                return -ETIME;
        case MC_CMD_ERR_EALREADY:
                return -EALREADY;
        case MC_CMD_ERR_ENOSPC:
                return -ENOSPC;
        case MC_CMD_ERR_ENOMEM:
                return -ENOMEM;
        case MC_CMD_ERR_ENOTSUP:
                return -EOPNOTSUPP;
        case MC_CMD_ERR_ALLOC_FAIL:
                return -ENOBUFS;
        case MC_CMD_ERR_MAC_EXIST:
                return -EADDRINUSE;
        case MC_CMD_ERR_NO_EVB_PORT:
                return -EAGAIN;
        default:
                return -EPROTO;
        }
}

static void cdx_mcdi_process_cleanup_list(struct cdx_mcdi *cdx,
                                          struct list_head *cleanup_list)
{
        struct cdx_mcdi_iface *mcdi = cdx_mcdi_if(cdx);
        unsigned int cleanups = 0;

        if (!mcdi)
                return;

        while (!list_empty(cleanup_list)) {
                struct cdx_mcdi_cmd *cmd =
                        list_first_entry(cleanup_list,
                                         struct cdx_mcdi_cmd, cleanup_list);
                cmd->completer(cdx, cmd->cookie, cmd->rc,
                               cmd->outbuf, cmd->outlen);
                list_del(&cmd->cleanup_list);
                kref_put(&cmd->ref, cdx_mcdi_cmd_release);
                ++cleanups;
        }

        if (cleanups) {
                bool all_done;

                mutex_lock(&mcdi->iface_lock);
                CDX_WARN_ON_PARANOID(cleanups > mcdi->outstanding_cleanups);
                all_done = (mcdi->outstanding_cleanups -= cleanups) == 0;
                mutex_unlock(&mcdi->iface_lock);
                if (all_done)
                        wake_up(&mcdi->cmd_complete_wq);
        }
}

static void _cdx_mcdi_cancel_cmd(struct cdx_mcdi_iface *mcdi,
                                 unsigned int handle,
                                 struct list_head *cleanup_list)
{
        struct cdx_mcdi_cmd *cmd;

        list_for_each_entry(cmd, &mcdi->cmd_list, list)
                if (cdx_mcdi_cmd_handle(cmd) == handle) {
                        switch (cmd->state) {
                        case MCDI_STATE_QUEUED:
                        case MCDI_STATE_RETRY:
                                pr_debug("command %#x inlen %zu cancelled in queue\n",
                                         cmd->cmd, cmd->inlen);
                                /* if not yet running, properly cancel it */
                                cmd->rc = -EPIPE;
                                cdx_mcdi_remove_cmd(mcdi, cmd, cleanup_list);
                                break;
                        case MCDI_STATE_RUNNING:
                        case MCDI_STATE_RUNNING_CANCELLED:
                        case MCDI_STATE_FINISHED:
                        default:
                                /* invalid state? */
                                WARN_ON(1);
                        }
                        break;
                }
}

static void cdx_mcdi_cancel_cmd(struct cdx_mcdi *cdx, struct cdx_mcdi_cmd *cmd)
{
        struct cdx_mcdi_iface *mcdi = cdx_mcdi_if(cdx);
        LIST_HEAD(cleanup_list);

        if (!mcdi)
                return;

        mutex_lock(&mcdi->iface_lock);
        cdx_mcdi_timeout_cmd(mcdi, cmd, &cleanup_list);
        mutex_unlock(&mcdi->iface_lock);
        cdx_mcdi_process_cleanup_list(cdx, &cleanup_list);
}

struct cdx_mcdi_blocking_data {
        struct kref ref;
        bool done;
        wait_queue_head_t wq;
        int rc;
        struct cdx_dword *outbuf;
        size_t outlen;
        size_t outlen_actual;
};

static void cdx_mcdi_blocking_data_release(struct kref *ref)
{
        kfree(container_of(ref, struct cdx_mcdi_blocking_data, ref));
}

static void cdx_mcdi_rpc_completer(struct cdx_mcdi *cdx, unsigned long cookie,
                                   int rc, struct cdx_dword *outbuf,
                                   size_t outlen_actual)
{
        struct cdx_mcdi_blocking_data *wait_data =
                (struct cdx_mcdi_blocking_data *)cookie;

        wait_data->rc = rc;
        memcpy(wait_data->outbuf, outbuf,
               min(outlen_actual, wait_data->outlen));
        wait_data->outlen_actual = outlen_actual;
        /* memory barrier */
        smp_wmb();
        wait_data->done = true;
        wake_up(&wait_data->wq);
        kref_put(&wait_data->ref, cdx_mcdi_blocking_data_release);
}

static int cdx_mcdi_rpc_sync(struct cdx_mcdi *cdx, unsigned int cmd,
                             const struct cdx_dword *inbuf, size_t inlen,
                             struct cdx_dword *outbuf, size_t outlen,
                             size_t *outlen_actual, bool quiet)
{
        struct cdx_mcdi_blocking_data *wait_data;
        struct cdx_mcdi_cmd *cmd_item;
        unsigned int handle;
        int rc;

        if (outlen_actual)
                *outlen_actual = 0;

        wait_data = kmalloc_obj(*wait_data);
        if (!wait_data)
                return -ENOMEM;

        cmd_item = kmalloc_obj(*cmd_item);
        if (!cmd_item) {
                kfree(wait_data);
                return -ENOMEM;
        }

        kref_init(&wait_data->ref);
        wait_data->done = false;
        init_waitqueue_head(&wait_data->wq);
        wait_data->outbuf = outbuf;
        wait_data->outlen = outlen;

        kref_init(&cmd_item->ref);
        cmd_item->quiet = quiet;
        cmd_item->cookie = (unsigned long)wait_data;
        cmd_item->completer = &cdx_mcdi_rpc_completer;
        cmd_item->cmd = cmd;
        cmd_item->inlen = inlen;
        cmd_item->inbuf = inbuf;

        /* Claim an extra reference for the completer to put. */
        kref_get(&wait_data->ref);
        rc = cdx_mcdi_rpc_async_internal(cdx, cmd_item, &handle);
        if (rc) {
                kref_put(&wait_data->ref, cdx_mcdi_blocking_data_release);
                goto out;
        }

        if (!wait_event_timeout(wait_data->wq, wait_data->done,
                                cdx_mcdi_rpc_timeout(cdx, cmd)) &&
            !wait_data->done) {
                pr_err("MC command 0x%x inlen %zu timed out (sync)\n",
                       cmd, inlen);

                cdx_mcdi_cancel_cmd(cdx, cmd_item);

                wait_data->rc = -ETIMEDOUT;
                wait_data->outlen_actual = 0;
        }

        if (outlen_actual)
                *outlen_actual = wait_data->outlen_actual;
        rc = wait_data->rc;

out:
        kref_put(&wait_data->ref, cdx_mcdi_blocking_data_release);

        return rc;
}

static bool cdx_mcdi_get_seq(struct cdx_mcdi_iface *mcdi, unsigned char *seq)
{
        *seq = mcdi->prev_seq;
        do {
                *seq = (*seq + 1) % ARRAY_SIZE(mcdi->seq_held_by);
        } while (mcdi->seq_held_by[*seq] && *seq != mcdi->prev_seq);
        return !mcdi->seq_held_by[*seq];
}

static int cdx_mcdi_rpc_async_internal(struct cdx_mcdi *cdx,
                                       struct cdx_mcdi_cmd *cmd,
                                       unsigned int *handle)
{
        struct cdx_mcdi_iface *mcdi = cdx_mcdi_if(cdx);
        LIST_HEAD(cleanup_list);

        if (!mcdi) {
                kref_put(&cmd->ref, cdx_mcdi_cmd_release);
                return -ENETDOWN;
        }

        if (mcdi->mode == MCDI_MODE_FAIL) {
                kref_put(&cmd->ref, cdx_mcdi_cmd_release);
                return -ENETDOWN;
        }

        cmd->mcdi = mcdi;
        INIT_WORK(&cmd->work, cdx_mcdi_cmd_work);
        INIT_LIST_HEAD(&cmd->list);
        INIT_LIST_HEAD(&cmd->cleanup_list);
        cmd->rc = 0;
        cmd->outbuf = NULL;
        cmd->outlen = 0;

        queue_work(mcdi->workqueue, &cmd->work);
        return 0;
}

static void cdx_mcdi_cmd_start_or_queue(struct cdx_mcdi_iface *mcdi,
                                        struct cdx_mcdi_cmd *cmd)
{
        struct cdx_mcdi *cdx = mcdi->cdx;
        u8 seq;

        if (!mcdi->db_held_by &&
            cdx_mcdi_get_seq(mcdi, &seq)) {
                cmd->seq = seq;
                cmd->reboot_seen = false;
                cdx_mcdi_send_request(cdx, cmd);
                cmd->state = MCDI_STATE_RUNNING;
        } else {
                cmd->state = MCDI_STATE_QUEUED;
        }
}

/* try to advance other commands */
static void cdx_mcdi_start_or_queue(struct cdx_mcdi_iface *mcdi,
                                    bool allow_retry)
{
        struct cdx_mcdi_cmd *cmd, *tmp;

        list_for_each_entry_safe(cmd, tmp, &mcdi->cmd_list, list)
                if (cmd->state == MCDI_STATE_QUEUED ||
                    (cmd->state == MCDI_STATE_RETRY && allow_retry))
                        cdx_mcdi_cmd_start_or_queue(mcdi, cmd);
}

/**
 * cdx_mcdi_process_cmd - Process an incoming MCDI response
 * @cdx:        Handle to the CDX MCDI structure
 * @outbuf:     Pointer to the response buffer received from the management controller
 * @len:        Length of the response buffer in bytes
 *
 * This function handles a response from the management controller. It locates the
 * corresponding command using the sequence number embedded in the header,
 * completes the command if it is still pending, and initiates any necessary cleanup.
 *
 * The function assumes that the response buffer is well-formed and at least one
 * dword in size.
 */
void cdx_mcdi_process_cmd(struct cdx_mcdi *cdx, struct cdx_dword *outbuf, int len)
{
        struct cdx_mcdi_iface *mcdi;
        struct cdx_mcdi_cmd *cmd;
        LIST_HEAD(cleanup_list);
        unsigned int respseq;

        if (!len || !outbuf) {
                pr_err("Got empty MC response\n");
                return;
        }

        mcdi = cdx_mcdi_if(cdx);
        if (!mcdi)
                return;

        respseq = CDX_DWORD_FIELD(outbuf[0], MCDI_HEADER_SEQ);

        mutex_lock(&mcdi->iface_lock);
        cmd = mcdi->seq_held_by[respseq];

        if (cmd) {
                if (cmd->state == MCDI_STATE_FINISHED) {
                        mutex_unlock(&mcdi->iface_lock);
                        kref_put(&cmd->ref, cdx_mcdi_cmd_release);
                        return;
                }

                cdx_mcdi_complete_cmd(mcdi, cmd, outbuf, len, &cleanup_list);
        } else {
                pr_err("MC response unexpected for seq : %0X\n", respseq);
        }

        mutex_unlock(&mcdi->iface_lock);

        cdx_mcdi_process_cleanup_list(mcdi->cdx, &cleanup_list);
}
EXPORT_SYMBOL_GPL(cdx_mcdi_process_cmd);

static void cdx_mcdi_cmd_work(struct work_struct *context)
{
        struct cdx_mcdi_cmd *cmd =
                container_of(context, struct cdx_mcdi_cmd, work);
        struct cdx_mcdi_iface *mcdi = cmd->mcdi;

        mutex_lock(&mcdi->iface_lock);

        cmd->handle = mcdi->prev_handle++;
        list_add_tail(&cmd->list, &mcdi->cmd_list);
        cdx_mcdi_cmd_start_or_queue(mcdi, cmd);

        mutex_unlock(&mcdi->iface_lock);
}

/*
 * Returns true if the MCDI module is finished with the command.
 * (examples of false would be if the command was proxied, or it was
 * rejected by the MC due to lack of resources and requeued).
 */
static bool cdx_mcdi_complete_cmd(struct cdx_mcdi_iface *mcdi,
                                  struct cdx_mcdi_cmd *cmd,
                                  struct cdx_dword *outbuf,
                                  int len,
                                  struct list_head *cleanup_list)
{
        size_t resp_hdr_len, resp_data_len;
        struct cdx_mcdi *cdx = mcdi->cdx;
        unsigned int respcmd, error;
        bool completed = false;
        int rc;

        /* ensure the command can't go away before this function returns */
        kref_get(&cmd->ref);

        respcmd = CDX_DWORD_FIELD(outbuf[0], MCDI_HEADER_CODE);
        error = CDX_DWORD_FIELD(outbuf[0], MCDI_HEADER_ERROR);

        if (respcmd != MC_CMD_V2_EXTN) {
                resp_hdr_len = 4;
                resp_data_len = CDX_DWORD_FIELD(outbuf[0], MCDI_HEADER_DATALEN);
        } else {
                resp_data_len = 0;
                resp_hdr_len = 8;
                if (len >= 8)
                        resp_data_len =
                                CDX_DWORD_FIELD(outbuf[1], MC_CMD_V2_EXTN_IN_ACTUAL_LEN);
        }

        if ((resp_hdr_len + resp_data_len) > len) {
                pr_warn("Incomplete MCDI response received %d. Expected %zu\n",
                        len, (resp_hdr_len + resp_data_len));
                resp_data_len = 0;
        }

        print_hex_dump_debug("MCDI RESP HEADER: ", DUMP_PREFIX_NONE, 32, 4,
                             outbuf, resp_hdr_len, false);
        print_hex_dump_debug("MCDI RESP PAYLOAD: ", DUMP_PREFIX_NONE, 32, 4,
                             outbuf + (resp_hdr_len / 4), resp_data_len, false);

        if (error && resp_data_len == 0) {
                /* MC rebooted during command */
                rc = -EIO;
        } else {
                if (WARN_ON_ONCE(error && resp_data_len < 4))
                        resp_data_len = 4;
                if (error) {
                        rc = CDX_DWORD_FIELD(outbuf[resp_hdr_len / 4], CDX_DWORD);
                        if (!cmd->quiet) {
                                int err_arg = 0;

                                if (resp_data_len >= MC_CMD_ERR_ARG_OFST + 4) {
                                        int offset = (resp_hdr_len + MC_CMD_ERR_ARG_OFST) / 4;

                                        err_arg = CDX_DWORD_VAL(outbuf[offset]);
                                }

                                _cdx_mcdi_display_error(cdx, cmd->cmd,
                                                        cmd->inlen, rc, err_arg,
                                                        cdx_mcdi_errno(cdx, rc));
                        }
                        rc = cdx_mcdi_errno(cdx, rc);
                } else {
                        rc = 0;
                }
        }

        /* free doorbell */
        if (mcdi->db_held_by == cmd)
                mcdi->db_held_by = NULL;

        if (cdx_cmd_cancelled(cmd)) {
                list_del(&cmd->list);
                kref_put(&cmd->ref, cdx_mcdi_cmd_release);
                completed = true;
        } else if (rc == MC_CMD_ERR_QUEUE_FULL) {
                cmd->state = MCDI_STATE_RETRY;
        } else {
                cmd->rc = rc;
                cmd->outbuf = outbuf + DIV_ROUND_UP(resp_hdr_len, 4);
                cmd->outlen = resp_data_len;
                cdx_mcdi_remove_cmd(mcdi, cmd, cleanup_list);
                completed = true;
        }

        /* free sequence number and buffer */
        mcdi->seq_held_by[cmd->seq] = NULL;

        cdx_mcdi_start_or_queue(mcdi, rc != MC_CMD_ERR_QUEUE_FULL);

        /* wake up anyone waiting for flush */
        wake_up(&mcdi->cmd_complete_wq);

        kref_put(&cmd->ref, cdx_mcdi_cmd_release);

        return completed;
}

static void cdx_mcdi_timeout_cmd(struct cdx_mcdi_iface *mcdi,
                                 struct cdx_mcdi_cmd *cmd,
                                 struct list_head *cleanup_list)
{
        struct cdx_mcdi *cdx = mcdi->cdx;

        pr_err("MC command 0x%x inlen %zu state %d timed out after %u ms\n",
               cmd->cmd, cmd->inlen, cmd->state,
               jiffies_to_msecs(jiffies - cmd->started));

        cmd->rc = -ETIMEDOUT;
        cdx_mcdi_remove_cmd(mcdi, cmd, cleanup_list);

        cdx_mcdi_mode_fail(cdx, cleanup_list);
}

/**
 * cdx_mcdi_rpc - Issue an MCDI command and wait for completion
 * @cdx: NIC through which to issue the command
 * @cmd: Command type number
 * @inbuf: Command parameters
 * @inlen: Length of command parameters, in bytes. Must be a multiple
 *      of 4 and no greater than %MCDI_CTL_SDU_LEN_MAX_V1.
 * @outbuf: Response buffer. May be %NULL if @outlen is 0.
 * @outlen: Length of response buffer, in bytes. If the actual
 *      response is longer than @outlen & ~3, it will be truncated
 *      to that length.
 * @outlen_actual: Pointer through which to return the actual response
 *      length. May be %NULL if this is not needed.
 *
 * This function may sleep and therefore must be called in process
 * context.
 *
 * Return: A negative error code, or zero if successful. The error
 *      code may come from the MCDI response or may indicate a failure
 *      to communicate with the MC. In the former case, the response
 *      will still be copied to @outbuf and *@outlen_actual will be
 *      set accordingly. In the latter case, *@outlen_actual will be
 *      set to zero.
 */
int cdx_mcdi_rpc(struct cdx_mcdi *cdx, unsigned int cmd,
                 const struct cdx_dword *inbuf, size_t inlen,
                 struct cdx_dword *outbuf, size_t outlen,
                 size_t *outlen_actual)
{
        return cdx_mcdi_rpc_sync(cdx, cmd, inbuf, inlen, outbuf, outlen,
                                 outlen_actual, false);
}
EXPORT_SYMBOL_GPL(cdx_mcdi_rpc);

/**
 * cdx_mcdi_rpc_async - Schedule an MCDI command to run asynchronously
 * @cdx: NIC through which to issue the command
 * @cmd: Command type number
 * @inbuf: Command parameters
 * @inlen: Length of command parameters, in bytes
 * @complete: Function to be called on completion or cancellation.
 * @cookie: Arbitrary value to be passed to @complete.
 *
 * This function does not sleep and therefore may be called in atomic
 * context.  It will fail if event queues are disabled or if MCDI
 * event completions have been disabled due to an error.
 *
 * If it succeeds, the @complete function will be called exactly once
 * in process context, when one of the following occurs:
 * (a) the completion event is received (in process context)
 * (b) event queues are disabled (in the process that disables them)
 */
int
cdx_mcdi_rpc_async(struct cdx_mcdi *cdx, unsigned int cmd,
                   const struct cdx_dword *inbuf, size_t inlen,
                   cdx_mcdi_async_completer *complete, unsigned long cookie)
{
        struct cdx_mcdi_cmd *cmd_item =
                kmalloc(sizeof(struct cdx_mcdi_cmd) + inlen, GFP_ATOMIC);

        if (!cmd_item)
                return -ENOMEM;

        kref_init(&cmd_item->ref);
        cmd_item->quiet = true;
        cmd_item->cookie = cookie;
        cmd_item->completer = complete;
        cmd_item->cmd = cmd;
        cmd_item->inlen = inlen;
        /* inbuf is probably not valid after return, so take a copy */
        cmd_item->inbuf = (struct cdx_dword *)(cmd_item + 1);
        memcpy(cmd_item + 1, inbuf, inlen);

        return cdx_mcdi_rpc_async_internal(cdx, cmd_item, NULL);
}

static void _cdx_mcdi_display_error(struct cdx_mcdi *cdx, unsigned int cmd,
                                    size_t inlen, int raw, int arg, int err_no)
{
        pr_err("MC command 0x%x inlen %d failed err_no=%d (raw=%d) arg=%d\n",
               cmd, (int)inlen, err_no, raw, arg);
}

/*
 * Set MCDI mode to fail to prevent any new commands, then cancel any
 * outstanding commands.
 * Caller must hold the mcdi iface_lock.
 */
static void cdx_mcdi_mode_fail(struct cdx_mcdi *cdx, struct list_head *cleanup_list)
{
        struct cdx_mcdi_iface *mcdi = cdx_mcdi_if(cdx);

        if (!mcdi)
                return;

        mcdi->mode = MCDI_MODE_FAIL;

        while (!list_empty(&mcdi->cmd_list)) {
                struct cdx_mcdi_cmd *cmd;

                cmd = list_first_entry(&mcdi->cmd_list, struct cdx_mcdi_cmd,
                                       list);
                _cdx_mcdi_cancel_cmd(mcdi, cdx_mcdi_cmd_handle(cmd), cleanup_list);
        }
}