/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2007, Juniper Networks, Inc.
 * Copyright (c) 2012-2013, SRI International
 * All rights reserved.
 *
 * Portions of this software were developed by SRI International and the
 * University of Cambridge Computer Laboratory under DARPA/AFRL contract
 * (FA8750-10-C-0237) ("CTSRD"), as part of the DARPA CRASH research
 * programme.
 *
 * 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.
 * 3. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * 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 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>
#include "opt_cfi.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/ioccom.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/malloc.h>   
#include <sys/proc.h>
#include <sys/sysctl.h>
#include <sys/types.h>
#include <sys/uio.h>

#include <sys/cfictl.h>

#include <machine/atomic.h>
#include <machine/bus.h>

#include <dev/cfi/cfi_var.h>

static d_open_t cfi_devopen;
static d_close_t cfi_devclose;
static d_read_t cfi_devread;
static d_write_t cfi_devwrite;
static d_ioctl_t cfi_devioctl;

struct cdevsw cfi_cdevsw = {
        .d_version      =       D_VERSION,
        .d_flags        =       0,
        .d_name         =       cfi_driver_name,
        .d_open         =       cfi_devopen,
        .d_close        =       cfi_devclose,
        .d_read         =       cfi_devread,
        .d_write        =       cfi_devwrite,
        .d_ioctl        =       cfi_devioctl,
};

/*
 * Begin writing into a new block/sector.  We read the sector into
 * memory and keep updating that, until we move into another sector
 * or the process stops writing. At that time we write the whole
 * sector to flash (see cfi_block_finish).  To avoid unneeded erase
 * cycles, keep a pristine copy of the sector on hand.
 */
int
cfi_block_start(struct cfi_softc *sc, u_int ofs)
{
        union {
                uint8_t         *x8;
                uint16_t        *x16;
                uint32_t        *x32;
        } ptr;
        u_int rofs, rsz;
        uint32_t val;
        int r;

        rofs = 0;
        for (r = 0; r < sc->sc_regions; r++) {
                rsz = sc->sc_region[r].r_blocks * sc->sc_region[r].r_blksz;
                if (ofs < rofs + rsz)
                        break;
                rofs += rsz;
        }
        if (r == sc->sc_regions)
                return (EFAULT);

        sc->sc_wrbufsz = sc->sc_region[r].r_blksz;
        sc->sc_wrbuf = malloc(sc->sc_wrbufsz, M_TEMP, M_WAITOK);
        sc->sc_wrofs = ofs - (ofs - rofs) % sc->sc_wrbufsz;

        /* Read the block from flash for byte-serving. */
        ptr.x8 = sc->sc_wrbuf;
        for (r = 0; r < sc->sc_wrbufsz; r += sc->sc_width) {
                val = cfi_read_raw(sc, sc->sc_wrofs + r);
                switch (sc->sc_width) {
                case 1:
                        *(ptr.x8)++ = val;
                        break;
                case 2:
                        *(ptr.x16)++ = val;
                        break;
                case 4:
                        *(ptr.x32)++ = val;
                        break;
                }
        }
        sc->sc_wrbufcpy = malloc(sc->sc_wrbufsz, M_TEMP, M_WAITOK);
        memcpy(sc->sc_wrbufcpy, sc->sc_wrbuf, sc->sc_wrbufsz);
        sc->sc_writing = 1;
        return (0);
}

/*
 * Finish updating the current block/sector by writing the compound
 * set of changes to the flash.
 */
int
cfi_block_finish(struct cfi_softc *sc)
{
        int error;

        error = cfi_write_block(sc);
        free(sc->sc_wrbuf, M_TEMP);
        free(sc->sc_wrbufcpy, M_TEMP);
        sc->sc_wrbuf = NULL;
        sc->sc_wrbufsz = 0;
        sc->sc_wrofs = 0;
        sc->sc_writing = 0;
        return (error);
}

static int
cfi_devopen(struct cdev *dev, int oflags, int devtype, struct thread *td)
{
        struct cfi_softc *sc;

        sc = dev->si_drv1;
        /* We allow only 1 open. */
        if (!atomic_cmpset_acq_ptr((uintptr_t *)&sc->sc_opened,
            (uintptr_t)NULL, (uintptr_t)td->td_proc))
                return (EBUSY);
        return (0);
}

static int
cfi_devclose(struct cdev *dev, int fflag, int devtype, struct thread *td)
{
        struct cfi_softc *sc;
        int error;

        sc = dev->si_drv1;
        /* Sanity. Not really necessary. */
        if (sc->sc_opened != td->td_proc)
                return (ENXIO);

        error = (sc->sc_writing) ? cfi_block_finish(sc) : 0;
        sc->sc_opened = NULL;
        return (error);
}

static int
cfi_devread(struct cdev *dev, struct uio *uio, int ioflag)
{
        union {
                uint8_t         x8[4];
                uint16_t        x16[2];
                uint32_t        x32[1];
        } buf;
        struct cfi_softc *sc;
        u_int ofs;
        uint32_t val;
        int error;

        sc = dev->si_drv1;

        error = (sc->sc_writing) ? cfi_block_finish(sc) : 0;
        if (!error)
                error = (uio->uio_offset > sc->sc_size) ? EIO : 0;

        while (error == 0 && uio->uio_resid > 0 &&
            uio->uio_offset < sc->sc_size) {
                ofs = uio->uio_offset;
                val = cfi_read_raw(sc, ofs);
                switch (sc->sc_width) {
                case 1:
                        buf.x8[0] = val;
                        break;
                case 2:
                        buf.x16[0] = val;
                        break;
                case 4:
                        buf.x32[0] = val;
                        break;
                }
                ofs &= sc->sc_width - 1;
                error = uiomove(buf.x8 + ofs,
                    MIN(uio->uio_resid, sc->sc_width - ofs), uio);
        }
        return (error);
}

static int
cfi_devwrite(struct cdev *dev, struct uio *uio, int ioflag)
{
        struct cfi_softc *sc;
        u_int ofs, top;
        int error;

        sc = dev->si_drv1;

        error = (uio->uio_offset > sc->sc_size) ? EIO : 0;
        while (error == 0 && uio->uio_resid > 0 &&
            uio->uio_offset < sc->sc_size) {
                ofs = uio->uio_offset;

                /*
                 * Finish the current block if we're about to write
                 * to a different block.
                 */
                if (sc->sc_writing) {
                        top = sc->sc_wrofs + sc->sc_wrbufsz;
                        if (ofs < sc->sc_wrofs || ofs >= top)
                                cfi_block_finish(sc);
                }

                /* Start writing to a (new) block if applicable. */
                if (!sc->sc_writing) {
                        error = cfi_block_start(sc, uio->uio_offset);
                        if (error)
                                break;
                }

                top = sc->sc_wrofs + sc->sc_wrbufsz;
                error = uiomove(sc->sc_wrbuf + ofs - sc->sc_wrofs,
                    MIN(top - ofs, uio->uio_resid), uio);
        }
        return (error);
}

static int
cfi_devioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
    struct thread *td)
{
        struct cfi_softc *sc;
        struct cfiocqry *rq;
        int error;
        u_char val;

        sc = dev->si_drv1;
        error = 0;

        switch (cmd) {
        case CFIOCQRY:
                if (sc->sc_writing) {
                        error = cfi_block_finish(sc);
                        if (error)
                                break;
                }
                rq = (struct cfiocqry *)data;
                if (rq->offset >= sc->sc_size / sc->sc_width)
                        return (ESPIPE);
                if (rq->offset > ULONG_MAX - rq->count ||
                    rq->offset + rq->count > sc->sc_size / sc->sc_width)
                        return (ENOSPC);

                while (!error && rq->count--) {
                        val = cfi_read_qry(sc, rq->offset++);
                        error = copyout(&val, rq->buffer++, 1);
                }
                break;
#ifdef CFI_SUPPORT_STRATAFLASH
        case CFIOCGFACTORYPR:
                error = cfi_intel_get_factory_pr(sc, (uint64_t *)data);
                break;
        case CFIOCGOEMPR:
                error = cfi_intel_get_oem_pr(sc, (uint64_t *)data);
                break;
        case CFIOCSOEMPR:
                error = cfi_intel_set_oem_pr(sc, *(uint64_t *)data);
                break;
        case CFIOCGPLR:
                error = cfi_intel_get_plr(sc, (uint32_t *)data);
                break;
        case CFIOCSPLR:
                error = cfi_intel_set_plr(sc);
                break;
#endif /* CFI_SUPPORT_STRATAFLASH */
        default:
                error = ENOIOCTL;
                break;
        }
        return (error);
}