// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Driver for the NXP SAA7164 PCIe bridge
 *
 *  Copyright (c) 2010-2015 Steven Toth <stoth@kernellabs.com>
 */

#include <linux/wait.h>

#include "saa7164.h"

static int saa7164_cmd_alloc_seqno(struct saa7164_dev *dev)
{
        int i, ret = -1;

        mutex_lock(&dev->lock);
        for (i = 0; i < SAA_CMD_MAX_MSG_UNITS; i++) {
                if (dev->cmds[i].inuse == 0) {
                        dev->cmds[i].inuse = 1;
                        dev->cmds[i].signalled = 0;
                        dev->cmds[i].timeout = 0;
                        ret = dev->cmds[i].seqno;
                        break;
                }
        }
        mutex_unlock(&dev->lock);

        return ret;
}

static void saa7164_cmd_free_seqno(struct saa7164_dev *dev, u8 seqno)
{
        mutex_lock(&dev->lock);
        if ((dev->cmds[seqno].inuse == 1) &&
                (dev->cmds[seqno].seqno == seqno)) {
                dev->cmds[seqno].inuse = 0;
                dev->cmds[seqno].signalled = 0;
                dev->cmds[seqno].timeout = 0;
        }
        mutex_unlock(&dev->lock);
}

static void saa7164_cmd_timeout_seqno(struct saa7164_dev *dev, u8 seqno)
{
        mutex_lock(&dev->lock);
        if ((dev->cmds[seqno].inuse == 1) &&
                (dev->cmds[seqno].seqno == seqno)) {
                dev->cmds[seqno].timeout = 1;
        }
        mutex_unlock(&dev->lock);
}

static u32 saa7164_cmd_timeout_get(struct saa7164_dev *dev, u8 seqno)
{
        int ret = 0;

        mutex_lock(&dev->lock);
        if ((dev->cmds[seqno].inuse == 1) &&
                (dev->cmds[seqno].seqno == seqno)) {
                ret = dev->cmds[seqno].timeout;
        }
        mutex_unlock(&dev->lock);

        return ret;
}

/* Commands to the f/w get marshelled to/from this code then onto the PCI
 * -bus/c running buffer. */
int saa7164_irq_dequeue(struct saa7164_dev *dev)
{
        int ret = SAA_OK, i = 0;
        u32 timeout;
        wait_queue_head_t *q = NULL;
        u8 tmp[512];
        dprintk(DBGLVL_CMD, "%s()\n", __func__);

        /* While any outstand message on the bus exists... */
        do {

                /* Peek the msg bus */
                struct tmComResInfo tRsp = { 0, 0, 0, 0, 0, 0 };
                ret = saa7164_bus_get(dev, &tRsp, NULL, 1);
                if (ret != SAA_OK)
                        break;

                q = &dev->cmds[tRsp.seqno].wait;
                timeout = saa7164_cmd_timeout_get(dev, tRsp.seqno);
                dprintk(DBGLVL_CMD, "%s() timeout = %d\n", __func__, timeout);
                if (!timeout) {
                        dprintk(DBGLVL_CMD,
                                "%s() signalled seqno(%d) (for dequeue)\n",
                                __func__, tRsp.seqno);
                        dev->cmds[tRsp.seqno].signalled = 1;
                        wake_up(q);
                } else {
                        printk(KERN_ERR
                                "%s() found timed out command on the bus\n",
                                        __func__);

                        /* Clean the bus */
                        ret = saa7164_bus_get(dev, &tRsp, &tmp, 0);
                        printk(KERN_ERR "%s() ret = %x\n", __func__, ret);
                        if (ret == SAA_ERR_EMPTY)
                                /* Someone else already fetched the response */
                                return SAA_OK;

                        if (ret != SAA_OK)
                                return ret;
                }

                /* It's unlikely to have more than 4 or 5 pending messages,
                 * ensure we exit at some point regardless.
                 */
        } while (i++ < 32);

        return ret;
}

/* Commands to the f/w get marshelled to/from this code then onto the PCI
 * -bus/c running buffer. */
static int saa7164_cmd_dequeue(struct saa7164_dev *dev)
{
        int ret;
        u32 timeout;
        wait_queue_head_t *q = NULL;
        u8 tmp[512];
        dprintk(DBGLVL_CMD, "%s()\n", __func__);

        while (true) {

                struct tmComResInfo tRsp = { 0, 0, 0, 0, 0, 0 };
                ret = saa7164_bus_get(dev, &tRsp, NULL, 1);
                if (ret == SAA_ERR_EMPTY)
                        return SAA_OK;

                if (ret != SAA_OK)
                        return ret;

                q = &dev->cmds[tRsp.seqno].wait;
                timeout = saa7164_cmd_timeout_get(dev, tRsp.seqno);
                dprintk(DBGLVL_CMD, "%s() timeout = %d\n", __func__, timeout);
                if (timeout) {
                        printk(KERN_ERR "found timed out command on the bus\n");

                        /* Clean the bus */
                        ret = saa7164_bus_get(dev, &tRsp, &tmp, 0);
                        printk(KERN_ERR "ret = %x\n", ret);
                        if (ret == SAA_ERR_EMPTY)
                                /* Someone else already fetched the response */
                                return SAA_OK;

                        if (ret != SAA_OK)
                                return ret;

                        if (tRsp.flags & PVC_CMDFLAG_CONTINUE)
                                printk(KERN_ERR "split response\n");
                        else
                                saa7164_cmd_free_seqno(dev, tRsp.seqno);

                        printk(KERN_ERR " timeout continue\n");
                        continue;
                }

                dprintk(DBGLVL_CMD, "%s() signalled seqno(%d) (for dequeue)\n",
                        __func__, tRsp.seqno);
                dev->cmds[tRsp.seqno].signalled = 1;
                wake_up(q);
                return SAA_OK;
        }
}

static int saa7164_cmd_set(struct saa7164_dev *dev, struct tmComResInfo *msg,
                           void *buf)
{
        struct tmComResBusInfo *bus = &dev->bus;
        u8 cmd_sent;
        u16 size, idx;
        u32 cmds;
        void *tmp;
        int ret = -1;

        if (!msg) {
                printk(KERN_ERR "%s() !msg\n", __func__);
                return SAA_ERR_BAD_PARAMETER;
        }

        mutex_lock(&dev->cmds[msg->id].lock);

        size = msg->size;
        cmds = size / bus->m_wMaxReqSize;
        if (size % bus->m_wMaxReqSize == 0)
                cmds -= 1;

        cmd_sent = 0;

        /* Split the request into smaller chunks */
        for (idx = 0; idx < cmds; idx++) {

                msg->flags |= SAA_CMDFLAG_CONTINUE;
                msg->size = bus->m_wMaxReqSize;
                tmp = buf + idx * bus->m_wMaxReqSize;

                ret = saa7164_bus_set(dev, msg, tmp);
                if (ret != SAA_OK) {
                        printk(KERN_ERR "%s() set failed %d\n", __func__, ret);

                        if (cmd_sent) {
                                ret = SAA_ERR_BUSY;
                                goto out;
                        }
                        ret = SAA_ERR_OVERFLOW;
                        goto out;
                }
                cmd_sent = 1;
        }

        /* If not the last command... */
        if (idx != 0)
                msg->flags &= ~SAA_CMDFLAG_CONTINUE;

        msg->size = size - idx * bus->m_wMaxReqSize;

        ret = saa7164_bus_set(dev, msg, buf + idx * bus->m_wMaxReqSize);
        if (ret != SAA_OK) {
                printk(KERN_ERR "%s() set last failed %d\n", __func__, ret);

                if (cmd_sent) {
                        ret = SAA_ERR_BUSY;
                        goto out;
                }
                ret = SAA_ERR_OVERFLOW;
                goto out;
        }
        ret = SAA_OK;

out:
        mutex_unlock(&dev->cmds[msg->id].lock);
        return ret;
}

/* Wait for a signal event, without holding a mutex. Either return TIMEOUT if
 * the event never occurred, or SAA_OK if it was signaled during the wait.
 */
static int saa7164_cmd_wait(struct saa7164_dev *dev, u8 seqno)
{
        wait_queue_head_t *q = NULL;
        int ret = SAA_BUS_TIMEOUT;
        unsigned long stamp;
        int r;

        if (saa_debug >= 4)
                saa7164_bus_dump(dev);

        dprintk(DBGLVL_CMD, "%s(seqno=%d)\n", __func__, seqno);

        mutex_lock(&dev->lock);
        if ((dev->cmds[seqno].inuse == 1) &&
                (dev->cmds[seqno].seqno == seqno)) {
                q = &dev->cmds[seqno].wait;
        }
        mutex_unlock(&dev->lock);

        if (q) {
                /* If we haven't been signalled we need to wait */
                if (dev->cmds[seqno].signalled == 0) {
                        stamp = jiffies;
                        dprintk(DBGLVL_CMD,
                                "%s(seqno=%d) Waiting (signalled=%d)\n",
                                __func__, seqno, dev->cmds[seqno].signalled);

                        /* Wait for signalled to be flagged or timeout */
                        /* In a highly stressed system this can easily extend
                         * into multiple seconds before the deferred worker
                         * is scheduled, and we're woken up via signal.
                         * We typically are signalled in < 50ms but it can
                         * take MUCH longer.
                         */
                        wait_event_timeout(*q, dev->cmds[seqno].signalled,
                                (HZ * waitsecs));
                        r = time_before(jiffies, stamp + (HZ * waitsecs));
                        if (r)
                                ret = SAA_OK;
                        else
                                saa7164_cmd_timeout_seqno(dev, seqno);

                        dprintk(DBGLVL_CMD, "%s(seqno=%d) Waiting res = %d (signalled=%d)\n",
                                __func__, seqno, r,
                                dev->cmds[seqno].signalled);
                } else
                        ret = SAA_OK;
        } else
                printk(KERN_ERR "%s(seqno=%d) seqno is invalid\n",
                        __func__, seqno);

        return ret;
}

int saa7164_cmd_send(struct saa7164_dev *dev, u8 id, enum tmComResCmd command,
        u16 controlselector, u16 size, void *buf)
{
        struct tmComResInfo command_t, *pcommand_t;
        struct tmComResInfo response_t, *presponse_t;
        u8 errdata[256];
        u16 resp_dsize;
        u16 data_recd;
        u32 loop;
        int ret;
        int safety = 0;

        dprintk(DBGLVL_CMD, "%s(unitid = %s (%d) , command = 0x%x, sel = 0x%x)\n",
                __func__, saa7164_unitid_name(dev, id), id,
                command, controlselector);

        if ((size == 0) || (buf == NULL)) {
                printk(KERN_ERR "%s() Invalid param\n", __func__);
                return SAA_ERR_BAD_PARAMETER;
        }

        /* Prepare some basic command/response structures */
        memset(&command_t, 0, sizeof(command_t));
        memset(&response_t, 0, sizeof(response_t));
        pcommand_t = &command_t;
        presponse_t = &response_t;
        command_t.id = id;
        command_t.command = command;
        command_t.controlselector = controlselector;
        command_t.size = size;

        /* Allocate a unique sequence number */
        ret = saa7164_cmd_alloc_seqno(dev);
        if (ret < 0) {
                printk(KERN_ERR "%s() No free sequences\n", __func__);
                ret = SAA_ERR_NO_RESOURCES;
                goto out;
        }

        command_t.seqno = (u8)ret;

        /* Send Command */
        resp_dsize = size;
        pcommand_t->size = size;

        dprintk(DBGLVL_CMD, "%s() pcommand_t.seqno = %d\n",
                __func__, pcommand_t->seqno);

        dprintk(DBGLVL_CMD, "%s() pcommand_t.size = %d\n",
                __func__, pcommand_t->size);

        ret = saa7164_cmd_set(dev, pcommand_t, buf);
        if (ret != SAA_OK) {
                printk(KERN_ERR "%s() set command failed %d\n", __func__, ret);

                if (ret != SAA_ERR_BUSY)
                        saa7164_cmd_free_seqno(dev, pcommand_t->seqno);
                else
                        /* Flag a timeout, because at least one
                         * command was sent */
                        saa7164_cmd_timeout_seqno(dev, pcommand_t->seqno);

                goto out;
        }

        /* With split responses we have to collect the msgs piece by piece */
        data_recd = 0;
        loop = 1;
        while (loop) {
                dprintk(DBGLVL_CMD, "%s() loop\n", __func__);

                ret = saa7164_cmd_wait(dev, pcommand_t->seqno);
                dprintk(DBGLVL_CMD, "%s() loop ret = %d\n", __func__, ret);

                /* if power is down and this is not a power command ... */

                if (ret == SAA_BUS_TIMEOUT) {
                        printk(KERN_ERR "Event timed out\n");
                        saa7164_cmd_timeout_seqno(dev, pcommand_t->seqno);
                        return ret;
                }

                if (ret != SAA_OK) {
                        printk(KERN_ERR "spurious error\n");
                        return ret;
                }

                /* Peek response */
                ret = saa7164_bus_get(dev, presponse_t, NULL, 1);
                if (ret == SAA_ERR_EMPTY) {
                        dprintk(4, "%s() SAA_ERR_EMPTY\n", __func__);
                        continue;
                }
                if (ret != SAA_OK) {
                        printk(KERN_ERR "peek failed\n");
                        return ret;
                }

                dprintk(DBGLVL_CMD, "%s() presponse_t->seqno = %d\n",
                        __func__, presponse_t->seqno);

                dprintk(DBGLVL_CMD, "%s() presponse_t->flags = 0x%x\n",
                        __func__, presponse_t->flags);

                dprintk(DBGLVL_CMD, "%s() presponse_t->size = %d\n",
                        __func__, presponse_t->size);

                /* Check if the response was for our command */
                if (presponse_t->seqno != pcommand_t->seqno) {

                        dprintk(DBGLVL_CMD,
                                "wrong event: seqno = %d, expected seqno = %d, will dequeue regardless\n",
                                presponse_t->seqno, pcommand_t->seqno);

                        ret = saa7164_cmd_dequeue(dev);
                        if (ret != SAA_OK) {
                                printk(KERN_ERR "dequeue failed, ret = %d\n",
                                        ret);
                                if (safety++ > 16) {
                                        printk(KERN_ERR
                                        "dequeue exceeded, safety exit\n");
                                        return SAA_ERR_BUSY;
                                }
                        }

                        continue;
                }

                if ((presponse_t->flags & PVC_RESPONSEFLAG_ERROR) != 0) {

                        memset(&errdata[0], 0, sizeof(errdata));

                        ret = saa7164_bus_get(dev, presponse_t, &errdata[0], 0);
                        if (ret != SAA_OK) {
                                printk(KERN_ERR "get error(2)\n");
                                return ret;
                        }

                        saa7164_cmd_free_seqno(dev, pcommand_t->seqno);

                        dprintk(DBGLVL_CMD, "%s() errdata %02x%02x%02x%02x\n",
                                __func__, errdata[0], errdata[1], errdata[2],
                                errdata[3]);

                        /* Map error codes */
                        dprintk(DBGLVL_CMD, "%s() cmd, error code  = 0x%x\n",
                                __func__, errdata[0]);

                        switch (errdata[0]) {
                        case PVC_ERRORCODE_INVALID_COMMAND:
                                dprintk(DBGLVL_CMD, "%s() INVALID_COMMAND\n",
                                        __func__);
                                ret = SAA_ERR_INVALID_COMMAND;
                                break;
                        case PVC_ERRORCODE_INVALID_DATA:
                                dprintk(DBGLVL_CMD, "%s() INVALID_DATA\n",
                                        __func__);
                                ret = SAA_ERR_BAD_PARAMETER;
                                break;
                        case PVC_ERRORCODE_TIMEOUT:
                                dprintk(DBGLVL_CMD, "%s() TIMEOUT\n", __func__);
                                ret = SAA_ERR_TIMEOUT;
                                break;
                        case PVC_ERRORCODE_NAK:
                                dprintk(DBGLVL_CMD, "%s() NAK\n", __func__);
                                ret = SAA_ERR_NULL_PACKET;
                                break;
                        case PVC_ERRORCODE_UNKNOWN:
                        case PVC_ERRORCODE_INVALID_CONTROL:
                                dprintk(DBGLVL_CMD,
                                        "%s() UNKNOWN OR INVALID CONTROL\n",
                                        __func__);
                                ret = SAA_ERR_NOT_SUPPORTED;
                                break;
                        default:
                                dprintk(DBGLVL_CMD, "%s() UNKNOWN\n", __func__);
                                ret = SAA_ERR_NOT_SUPPORTED;
                        }

                        /* See of other commands are on the bus */
                        if (saa7164_cmd_dequeue(dev) != SAA_OK)
                                printk(KERN_ERR "dequeue(2) failed\n");

                        return ret;
                }

                /* If response is invalid */
                if ((presponse_t->id != pcommand_t->id) ||
                        (presponse_t->command != pcommand_t->command) ||
                        (presponse_t->controlselector !=
                                pcommand_t->controlselector) ||
                        (((resp_dsize - data_recd) != presponse_t->size) &&
                                !(presponse_t->flags & PVC_CMDFLAG_CONTINUE)) ||
                        ((resp_dsize - data_recd) < presponse_t->size)) {

                        /* Invalid */
                        dprintk(DBGLVL_CMD, "%s() Invalid\n", __func__);
                        ret = saa7164_bus_get(dev, presponse_t, NULL, 0);
                        if (ret != SAA_OK) {
                                printk(KERN_ERR "get failed\n");
                                return ret;
                        }

                        /* See of other commands are on the bus */
                        if (saa7164_cmd_dequeue(dev) != SAA_OK)
                                printk(KERN_ERR "dequeue(3) failed\n");
                        continue;
                }

                /* OK, now we're actually getting out correct response */
                ret = saa7164_bus_get(dev, presponse_t, buf + data_recd, 0);
                if (ret != SAA_OK) {
                        printk(KERN_ERR "get failed\n");
                        return ret;
                }

                data_recd = presponse_t->size + data_recd;
                if (resp_dsize == data_recd) {
                        dprintk(DBGLVL_CMD, "%s() Resp recd\n", __func__);
                        break;
                }

                /* See of other commands are on the bus */
                if (saa7164_cmd_dequeue(dev) != SAA_OK)
                        printk(KERN_ERR "dequeue(3) failed\n");
        } /* (loop) */

        /* Release the sequence number allocation */
        saa7164_cmd_free_seqno(dev, pcommand_t->seqno);

        /* if powerdown signal all pending commands */

        dprintk(DBGLVL_CMD, "%s() Calling dequeue then exit\n", __func__);

        /* See of other commands are on the bus */
        if (saa7164_cmd_dequeue(dev) != SAA_OK)
                printk(KERN_ERR "dequeue(4) failed\n");

        ret = SAA_OK;
out:
        return ret;
}