/*      $NetBSD: isv.c,v 1.7 2014/07/25 08:10:37 dholland Exp $ */

/*-
 * Copyright (c) 2008 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by David Young.
 *
 * 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``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 FOUNDATION 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: isv.c,v 1.7 2014/07/25 08:10:37 dholland Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <sys/conf.h>

#include <uvm/uvm_extern.h>

#include <sys/bus.h>

#include <dev/isa/isareg.h>
#include <dev/isa/isavar.h>

#include <dev/isa/isvio.h>

#define ISV_CONTROL     0x0             /* control: write-only */
#define ISV_CONTROL_MODE_MASK           __BIT(0)
#define ISV_CONTROL_MODE_CAPTURE        __SHIFTIN(0, ISV_CONTROL_MODE_MASK)
#define ISV_CONTROL_MODE_READ           __SHIFTIN(1, ISV_CONTROL_MODE_MASK)
#define ISV_CONTROL_COUNTER_MASK        __BIT(1)
#define ISV_CONTROL_COUNTER_RESET       __SHIFTIN(1, ISV_CONTROL_COUNTER_MASK)
#define ISV_CONTROL_COUNTER_AUTOINC     __SHIFTIN(0, ISV_CONTROL_COUNTER_MASK)

#define ISV_DATA        ISV_CONTROL     /* data: read-only */

#define ISV_STATUS      0x2             /* status: read-only */
#define ISV_STATUS_VIDEO_MASK           __BIT(15)
#define ISV_STATUS_VIDEO_RETRACE        __SHIFTIN(0, ISV_STATUS_VIDEO_MASK)
#define ISV_STATUS_VIDEO_WRITE          __SHIFTIN(1, ISV_STATUS_VIDEO_MASK)

struct isv_regs {
        bus_space_tag_t         ir_bt;
        bus_space_handle_t      ir_bh;
};

enum isv_state {
          ISV_S_CAPTURE0 = 0
        , ISV_S_CAPTURE1 = 1
        , ISV_S_CAPTURE2 = 2
        , ISV_S_RETRACE = 3
};

struct isv_softc {
        struct isv_regs sc_ir;
        device_t        sc_dev;
        uint16_t        *sc_frame;
        int             sc_speed;
};

extern struct cfdriver isv_cd;

static dev_type_ioctl(isv_ioctl);
static dev_type_open(isv_open);
static dev_type_mmap(isv_mmap);

static int      isv_capture(struct isv_softc *);
static int      isv_match(device_t, cfdata_t, void *);
static void     isv_attach(device_t, device_t, void *);
static int      isv_detach(device_t, int);
static uint16_t isv_read(struct isv_regs *, bus_size_t);
static void     isv_write(struct isv_regs *, bus_size_t, uint16_t);
static bool     isv_retrace(struct isv_regs *);
static int      isv_retrace_wait(struct isv_regs *, int *,
    const struct timeval *);
static int      isv_capture_wait(struct isv_regs *, int *,
    const struct timeval *);
static bool     isv_delta(int *, bool);
static int      isv_probe(struct isv_regs *);

CFATTACH_DECL_NEW(isv_isa, sizeof(struct isv_softc),
    isv_match, isv_attach, isv_detach, NULL);

const struct cdevsw isv_cdevsw = {
        .d_open = isv_open,
        .d_close = nullclose,
        .d_read = noread,
        .d_write = nowrite,
        .d_ioctl = isv_ioctl,
        .d_stop = nostop,
        .d_tty = notty,
        .d_poll = nopoll,
        .d_mmap = isv_mmap,
        .d_kqfilter = nokqfilter,
        .d_discard = nodiscard,
        .d_flag = D_OTHER
};

static uint16_t
isv_read(struct isv_regs *ir, bus_size_t reg)
{
        return bus_space_read_2(ir->ir_bt, ir->ir_bh, reg);
}

static void
isv_write(struct isv_regs *ir, bus_size_t reg, uint16_t val)
{
        bus_space_write_2(ir->ir_bt, ir->ir_bh, reg, val);
}

static bool
isv_retrace(struct isv_regs *ir)
{
        uint16_t video;

        video = isv_read(ir, ISV_STATUS) & ISV_STATUS_VIDEO_MASK;
        return video == ISV_STATUS_VIDEO_RETRACE;
}

#define state_and_input(__state, __retrace)     \
        (((__state) << 1) | ((__retrace) ? 1 : 0))

static bool
isv_delta(int *state, bool retrace)
{
        bool transition = false;

        switch (state_and_input(*state, retrace)) {
        case state_and_input(ISV_S_CAPTURE0, false):
        case state_and_input(ISV_S_RETRACE, true):
                break;
        case state_and_input(ISV_S_CAPTURE2, true):
                transition = true;
                /*FALLTHROUGH*/
        case state_and_input(ISV_S_CAPTURE1, true):
        case state_and_input(ISV_S_CAPTURE0, true):
                (*state)++;
                break;
        case state_and_input(ISV_S_RETRACE, false):
                transition = true;
                /*FALLTHROUGH*/
        case state_and_input(ISV_S_CAPTURE2, false):
        case state_and_input(ISV_S_CAPTURE1, false):
                *state = ISV_S_CAPTURE0;
                break;
        }
        return transition;
}

static int
isv_probe(struct isv_regs *ir)
{
        int state, transitions;
        struct timeval end, now,
            wait = {.tv_sec = 0, .tv_usec = 1000000 * 4 / 30};

        aprint_debug("%s: resetting\n", __func__);
        isv_write(ir, ISV_CONTROL,
            ISV_CONTROL_MODE_CAPTURE|ISV_CONTROL_COUNTER_AUTOINC);

        aprint_debug("%s: waiting\n", __func__);

        microtime(&now);
        timeradd(&now, &wait, &end);

        state = transitions = 0;

        do {
                if (isv_delta(&state, isv_retrace(ir)))
                        transitions++;

                if (state == ISV_S_CAPTURE0 || state == ISV_S_RETRACE)
                        microtime(&now);
        } while (timercmp(&now, &end, <));

        aprint_debug("%s: %d transitions\n", __func__, transitions);

        return transitions >= 4 && transitions <= 10;
}

static int
isv_match(device_t parent, cfdata_t match, void *aux)
{
        struct isv_regs ir;
        struct isa_attach_args *ia = aux;
        int rv;

        /* Must supply an address */
        if (ia->ia_nio < 1 || ia->ia_io[0].ir_addr == ISA_UNKNOWN_PORT)
                return 0;

        ir.ir_bt = ia->ia_iot;

        if (bus_space_map(ir.ir_bt, ia->ia_io[0].ir_addr, 8, 0, &ir.ir_bh))
                return 0;

        rv = isv_probe(&ir);

        bus_space_unmap(ir.ir_bt, ir.ir_bh, 8);

        if (rv) {
                ia->ia_nio = 1;
                ia->ia_io[0].ir_size = 8;

                ia->ia_niomem = 0;
                ia->ia_nirq = 0;
                ia->ia_ndrq = 0;
        }

        return rv;
}


static void
isv_attach(device_t parent, device_t self, void *aux)
{
        struct isv_softc *sc = device_private(self);
        struct isv_regs *ir = &sc->sc_ir;
        struct isa_attach_args *ia = aux;

        ir->ir_bt = ia->ia_iot;

        if (bus_space_map(ir->ir_bt, ia->ia_io[0].ir_addr, 8, 0, &ir->ir_bh)) {
                aprint_error(": can't map i/o space\n");
                return;
        }

        /* Bus-independent attachment */
        sc->sc_dev = self;

        aprint_normal(": IDEC Supervision/16\n"); 

        /* TBD */
}

int
isv_open(dev_t dev, int flag, int devtype, lwp_t *l)
{
        vaddr_t va;
        struct isv_softc *sc = device_lookup_private(&isv_cd, minor(dev));

        if (sc == NULL)
                return ENXIO;

        if (sc->sc_frame != NULL)
                return 0;

        if ((va = uvm_km_alloc(kernel_map, ISV_WIDTH * ISV_LINES, PAGE_SIZE,
            UVM_KMF_WIRED|UVM_KMF_ZERO|UVM_KMF_CANFAIL|UVM_KMF_WAITVA)) == 0)
                return ENOMEM;

        sc->sc_frame = (uint16_t *)(void *)va;
        return 0;
}

/* wait for retrace */
static int
isv_retrace_wait(struct isv_regs *ir, int *state, const struct timeval *end)
{
        struct timeval now;

        for (;;) {
                if (!isv_delta(state, isv_retrace(ir))) {
                        microtime(&now);
                        continue;
                }
                if (*state == ISV_S_RETRACE)
                        break;
                if (*state != ISV_S_CAPTURE0)
                        continue;

                microtime(&now);
                if (timercmp(&now, end, >=))
                        return EIO;
        }
        return 0;
}

/* wait for capture mode */
static int
isv_capture_wait(struct isv_regs *ir, int *state, const struct timeval *end)
{
        struct timeval now;

        for (;;) {
                if (!isv_delta(state, isv_retrace(ir))) {
                        microtime(&now);
                        continue;
                }
                if (*state != ISV_S_RETRACE)
                        break;

                microtime(&now);
                if (timercmp(&now, end, >=))
                        return EIO;
        }
        return 0;
}


static int
isv_capture(struct isv_softc *sc)
{
        int speed;
        int rc, state = ISV_S_CAPTURE0;
        struct timeval diff, end, start, stop;
        static const struct timeval wait = {.tv_sec = 0, .tv_usec = 200000};
        struct isv_regs *ir = &sc->sc_ir;

        if (sc->sc_frame == NULL)
                return EAGAIN;

        microtime(&start);

        timeradd(&start, &wait, &end);

        speed = sc->sc_speed;
        sc->sc_speed = 0;

        if (speed < 1 && (rc = isv_retrace_wait(ir, &state, &end)) != 0)
                return rc;

        if (speed < 2 && (rc = isv_capture_wait(ir, &state, &end)) != 0)
                return rc;

        if ((rc = isv_retrace_wait(ir, &state, &end)) != 0)
                return rc;

        microtime(&stop);

        timersub(&stop, &start, &diff);

        aprint_debug_dev(sc->sc_dev, "%ssync in %" PRId64 ".%06d seconds\n",
            (speed < 1) ? "" : ((speed < 2) ? "faster " : "fastest "),
            diff.tv_sec, diff.tv_usec);

        microtime(&start);

        /* enter read mode, then toggle counter mode,
         * autoinc -> reset -> autoinc, so that we start reading
         * at the top of the frame.
         */
        isv_write(ir, ISV_CONTROL,
            ISV_CONTROL_MODE_READ|ISV_CONTROL_COUNTER_AUTOINC);
        isv_write(ir, ISV_CONTROL,
            ISV_CONTROL_MODE_READ|ISV_CONTROL_COUNTER_RESET);
        isv_write(ir, ISV_CONTROL,
            ISV_CONTROL_MODE_READ|ISV_CONTROL_COUNTER_AUTOINC);
        /* read one dummy word to prime the state machine on the
         * image capture board
         */
        isv_read(ir, ISV_DATA);
        bus_space_read_multi_stream_2(ir->ir_bt, ir->ir_bh, ISV_DATA,
            sc->sc_frame, ISV_WIDTH * ISV_LINES / 2);

        /* restore to initial conditions */
        isv_write(ir, ISV_CONTROL,
            ISV_CONTROL_MODE_CAPTURE|ISV_CONTROL_COUNTER_AUTOINC);

        microtime(&stop);

        timersub(&stop, &start, &diff);

        aprint_debug_dev(sc->sc_dev, "read in %" PRId64 ".%06d seconds\n",
                diff.tv_sec, diff.tv_usec);

        state = 0;

        if (isv_retrace_wait(ir, &state, &end) != 0)
                return 0;
        sc->sc_speed++;

        if (isv_capture_wait(ir, &state, &end) != 0)
                return 0;
        sc->sc_speed++;

        return 0;
}

int
isv_ioctl(dev_t dev, u_long cmd, void *data, int flag, lwp_t *l)
{
        struct isv_cmd ic;
        struct isv_softc *sc = device_lookup_private(&isv_cd, minor(dev));

        if (cmd != ISV_CMD)
                return ENOTTY;

        memcpy(&ic, data, sizeof(ic));

        if (ic.c_cmd != ISV_CMD_READ)
                return EINVAL;

        ic.c_frameno = 0;

        return isv_capture(sc);
}

paddr_t
isv_mmap(dev_t dev, off_t offset, int prot)
{
        struct isv_softc *sc = device_lookup_private(&isv_cd, minor(dev));
        paddr_t pa;

        if ((prot & ~(VM_PROT_READ)) != 0)
                return -1;

        if (sc->sc_frame == NULL)
                return -1;

        if (offset >= ISV_WIDTH * ISV_LINES)
                return -1;

        if (!pmap_extract(pmap_kernel(), (vaddr_t)&sc->sc_frame[offset/2], &pa))
                return -1;

        return atop(pa);
}

static int
isv_detach(device_t self, int flags)
{
        struct isv_softc *sc = device_private(self);
        struct isv_regs *ir = &sc->sc_ir;

        if (sc->sc_frame != NULL) {
                uvm_km_free(kernel_map, (vaddr_t)sc->sc_frame,
                    ISV_WIDTH * ISV_LINES, UVM_KMF_WIRED);
        }
        bus_space_unmap(ir->ir_bt, ir->ir_bh, 8);
        return 0;
}