/*      $NetBSD: pud.c,v 1.11 2011/07/08 09:32:45 mrg Exp $     */

/*
 * Copyright (c) 2007  Antti Kantee.  All Rights Reserved.
 *
 * Development of this software was supported by the
 * Research Foundation of Helsinki University of Technology
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: pud.c,v 1.11 2011/07/08 09:32:45 mrg Exp $");

#include <sys/param.h>
#include <sys/conf.h>
#include <sys/kmem.h>
#include <sys/module.h>
#include <sys/poll.h>
#include <sys/queue.h>

#include <dev/pud/pud_sys.h>
#include <dev/putter/putter_sys.h>

void    pudattach(void);

static int      pud_putter_getout(void *, size_t, int, uint8_t **,
                                  size_t *, void **);
static void     pud_putter_releaseout(void *, void *, int);
static int      pud_putter_dispatch(void *, struct putter_hdr *);
static size_t   pud_putter_waitcount(void *);
static int      pud_putter_close(void *);

struct putter_ops pud_putter = {
        .pop_getout     = pud_putter_getout,
        .pop_releaseout = pud_putter_releaseout,
        .pop_waitcount  = pud_putter_waitcount,
        .pop_dispatch   = pud_putter_dispatch,
        .pop_close      = pud_putter_close,
};

extern struct bdevsw pud_bdevsw;
extern struct cdevsw pud_cdevsw;

kmutex_t pud_mtx;
static LIST_HEAD(, pud_dev) pudlist = LIST_HEAD_INITIALIZER(pudlist);

static uint64_t
nextreq(struct pud_dev *pd)
{
        uint64_t rv;

        mutex_enter(&pd->pd_mtx);
        rv = pd->pd_nextreq++;
        mutex_exit(&pd->pd_mtx);

        return rv;
}

static int
pud_putter_getout(void *this, size_t maxsize, int nonblock,
        uint8_t **data, size_t *dlen, void **cookie)
{
        struct pud_dev *pd = this;
        struct pud_touser *putp = NULL;
        int error = 0;

        mutex_enter(&pd->pd_mtx);
        for (;;) {
                if (TAILQ_EMPTY(&pd->pd_waitq_req)) {
                        if (nonblock) {
                                error = EWOULDBLOCK;
                                break;
                        }

                        error = cv_wait_sig(&pd->pd_waitq_req_cv, &pd->pd_mtx);
                        if (error)
                                break;
                        else
                                continue;
                }

                putp = TAILQ_FIRST(&pd->pd_waitq_req);
                TAILQ_REMOVE(&pd->pd_waitq_req, putp, pt_entries);
                KASSERT(error == 0);
                break;
        }
        mutex_exit(&pd->pd_mtx);

        if (error == 0) {
                *data = (uint8_t *)putp->pt_pdr;
                *dlen = putp->pt_pdr->pdr_pth.pth_framelen;
                *cookie = putp;
        }

        return error;
}

static void
pud_putter_releaseout(void *this, void *cookie, int status)
{
        struct pud_dev *pd = this;
        struct pud_touser *putp = cookie;

        mutex_enter(&pd->pd_mtx);
        TAILQ_INSERT_TAIL(&pd->pd_waitq_resp, putp, pt_entries);
        mutex_exit(&pd->pd_mtx);

}

static size_t
pud_putter_waitcount(void *this)
{
        struct pud_dev *pd = this;
        size_t rv;

        mutex_enter(&pd->pd_mtx);
        rv = pd->pd_waitcount;
        mutex_exit(&pd->pd_mtx);

        return rv;
}

static int
pudop_dev(struct pud_dev *pd, struct pud_req *pdr)
{
        struct putter_hdr *pth = (void *)pdr;
        struct pud_touser *putp;

        mutex_enter(&pd->pd_mtx);
        TAILQ_FOREACH(putp, &pd->pd_waitq_resp, pt_entries)
                if (putp->pt_pdr->pdr_reqid == pdr->pdr_reqid)
                        break;
        if (putp == NULL) {
                mutex_exit(&pd->pd_mtx);
                return EINVAL;
        }
        TAILQ_REMOVE(&pd->pd_waitq_resp, putp, pt_entries);
        mutex_exit(&pd->pd_mtx);

        if (pth->pth_framelen > putp->pt_pdr->pdr_len) {
                return EINVAL;
        }
        memcpy(putp->pt_pdr, pth, pth->pth_framelen);
        cv_signal(&putp->pt_cv);

        return 0;
}

/*
 * Register our major number.  Always register char device functions,
 * register block devices optionally.
 *
 * XXX: no way to configure "any major you like" currently.
 */
static int
pudconf_reg(struct pud_dev *pd, struct pud_conf_reg *pcr)
{
        struct bdevsw *bsw;
        devmajor_t cmajor, bmajor;
        int error;

        if (pcr->pm_version != (PUD_DEVELVERSION | PUD_VERSION)) {
                printf("pud version mismatch %d vs %d\n",
                    pcr->pm_version & ~PUD_DEVELVERSION, PUD_VERSION);
                return EINVAL; /* XXX */
        }

        cmajor = major(pcr->pm_regdev);
        if (pcr->pm_flags & PUD_CONFFLAG_BDEV) {
                bsw = &pud_bdevsw;
                bmajor = cmajor;
        } else {
                bsw = NULL;
                bmajor = NODEVMAJOR;
        }

        pcr->pm_devname[PUD_DEVNAME_MAX] = '\0';
        error = devsw_attach(pcr->pm_devname, bsw, &bmajor,
            &pud_cdevsw, &cmajor);
        if (error == 0)
                pd->pd_dev = pcr->pm_regdev;

        return error;
}

static int
pudop_conf(struct pud_dev *pd, struct pud_req *pdr)
{
        int rv;

        switch (pdr->pdr_reqtype) {
        case PUD_CONF_REG:
                rv = pudconf_reg(pd, (struct pud_conf_reg *)pdr);
                break;
        case PUD_CONF_DEREG:
                /* unimplemented */
                rv = 0;
                break;
        default:
                rv = EINVAL;
                break;
        }

        return rv;
}

static int
pud_putter_dispatch(void *this, struct putter_hdr *pth)
{
        struct pud_dev *pd = this;
        struct pud_req *pdr = (void *)pth;
        int rv;

        if (pdr->pdr_pth.pth_framelen < sizeof(struct pud_req))
                return EINVAL;

        switch (pdr->pdr_reqclass) {
        case PUD_REQ_CDEV:
        case PUD_REQ_BDEV:
                rv = pudop_dev(pd, pdr);
                break;
        case PUD_REQ_CONF:
                rv = pudop_conf(pd, pdr);
                break;
        default:
                rv = EINVAL;
                break;
        }

        return rv;
}

/* Device server severed the umbilical cord */
static int
pud_putter_close(void *this)
{
        struct pud_dev *pd = this;
        struct pud_touser *putp;

        mutex_enter(&pud_mtx);
        LIST_REMOVE(pd, pd_entries);
        mutex_exit(&pud_mtx);

        mutex_enter(&pd->pd_mtx);
        while ((putp = TAILQ_FIRST(&pd->pd_waitq_req)) != NULL) {
                putp->pt_pdr->pdr_rv = ENXIO;
                cv_signal(&putp->pt_cv);
                TAILQ_REMOVE(&pd->pd_waitq_req, putp, pt_entries);
        }

        while ((putp = TAILQ_FIRST(&pd->pd_waitq_resp)) != NULL) {
                putp->pt_pdr->pdr_rv = ENXIO;
                cv_signal(&putp->pt_cv);
                TAILQ_REMOVE(&pd->pd_waitq_resp, putp, pt_entries);
        }
        if (pd->pd_waitcount)
                cv_wait(&pd->pd_draincv, &pd->pd_mtx);
        KASSERT(pd->pd_waitcount == 0);

        mutex_exit(&pd->pd_mtx);

        if (pd->pd_dev)
                devsw_detach(&pud_bdevsw /* XXX */, &pud_cdevsw);
                
        putter_detach(pd->pd_pi);

        mutex_destroy(&pd->pd_mtx);
        cv_destroy(&pd->pd_draincv);
        cv_destroy(&pd->pd_waitq_req_cv);
        kmem_free(pd, sizeof(struct pud_dev));

        return 0;
}

struct pud_dev *
pud_dev2pud(dev_t dev)
{
        struct pud_dev *pd;

        mutex_enter(&pud_mtx);
        LIST_FOREACH(pd, &pudlist, pd_entries)
                if (major(pd->pd_dev) == major(dev))
                        break;
        mutex_exit(&pud_mtx);

        return pd;
}

/* Toss request to the device server and wait for result */
int
pud_request(dev_t dev, void *data, size_t dlen, int class, int type)
{
        struct pud_touser put;
        struct pud_req *pdr = data;
        struct pud_dev *pd;

        pd = pud_dev2pud(dev);
        if (pd == NULL)
                return ENXIO;

        pdr->pdr_dev = dev;
        pdr->pdr_len = pdr->pdr_pth.pth_framelen = dlen;
        pdr->pdr_reqid = nextreq(pd);

        pdr->pdr_reqclass = class;
        pdr->pdr_reqtype = type;

        put.pt_pdr = pdr;
        cv_init(&put.pt_cv, "pudresp");

        mutex_enter(&pd->pd_mtx);
        pd->pd_waitcount++;

        TAILQ_INSERT_TAIL(&pd->pd_waitq_req, &put, pt_entries);
        putter_notify(pd->pd_pi);
        cv_broadcast(&pd->pd_waitq_req_cv);
        cv_wait(&put.pt_cv, &pd->pd_mtx);

        if (--pd->pd_waitcount == 0)
                cv_signal(&pd->pd_draincv);
        mutex_exit(&pd->pd_mtx);
        cv_destroy(&put.pt_cv);

        return pdr->pdr_rv;
}

/* Called from putter based on minor dev number */
int
pud_config(int fd, int flags, int fmt)
{
        struct pud_dev *pd;

        pd = kmem_zalloc(sizeof(struct pud_dev), KM_SLEEP);
        pd->pd_pi = putter_attach(curlwp->l_proc->p_pid, fd, pd, &pud_putter);
        if (pd->pd_pi == NULL) {
                kmem_free(pd, sizeof(struct pud_dev));
                return ENOENT; /* XXX */
        }
        pd->pd_dev = NODEV;

        mutex_init(&pd->pd_mtx, MUTEX_DEFAULT, IPL_NONE);
        TAILQ_INIT(&pd->pd_waitq_req);
        TAILQ_INIT(&pd->pd_waitq_resp);
        cv_init(&pd->pd_waitq_req_cv, "pudreq");
        cv_init(&pd->pd_draincv, "pudrain");

        mutex_enter(&pud_mtx);
        LIST_INSERT_HEAD(&pudlist, pd, pd_entries);
        mutex_exit(&pud_mtx);

        return 0;
}

void
pudattach(void)
{
        int error;

        if ((error = putter_register(pud_config, PUTTER_MINOR_PUD)) != 0) {
                printf("pudattach: can't register to putter: %d\n", error);
                return;
        }
        mutex_init(&pud_mtx, MUTEX_DEFAULT, IPL_NONE);
}

MODULE(MODULE_CLASS_DRIVER, pud, "putter");

static int
pud_modcmd(modcmd_t cmd, void *arg)
{
        #ifdef _MODULE
        devmajor_t bmajor = NODEVMAJOR, cmajor = NODEVMAJOR;

        switch (cmd) {
        case MODULE_CMD_INIT:
                pudattach();
                return devsw_attach("pud", NULL, &bmajor,
                    &pud_cdevsw, &cmajor);
        case MODULE_CMD_FINI:
                return ENOTTY; /* XXX: puddetach */
        default:
                return ENOTTY;
        }
        #else
        if (cmd == MODULE_CMD_INIT)
                return 0;
        return ENOTTY;
        #endif
}