/*      $NetBSD: nandemulator.c,v 1.10 2023/05/10 00:11:16 riastradh Exp $      */

/*-
 * Copyright (c) 2011 Department of Software Engineering,
 *                    University of Szeged, Hungary
 * Copyright (c) 2011 Adam Hoka <ahoka@NetBSD.org>
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by the Department of Software Engineering, University of Szeged, Hungary
 *
 * 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 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: nandemulator.c,v 1.10 2023/05/10 00:11:16 riastradh Exp $");

/* XXX this code likely needs work */

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

#include "nandemulator.h"

#include <dev/nand/nand.h>
#include <dev/nand/onfi.h>
#include <dev/nand/nand_crc.h>

#include "ioconf.h"

extern struct cfdriver nandemulator_cd;

static int nandemulator_match(device_t, cfdata_t, void *);
static void nandemulator_attach(device_t, device_t, void *);
static int nandemulator_detach(device_t, int);

static void nandemulator_device_reset(device_t);
static void nandemulator_command(device_t, uint8_t);
static void nandemulator_address(device_t, uint8_t);
static void nandemulator_busy(device_t);
static void nandemulator_read_1(device_t, uint8_t *);
static void nandemulator_write_1(device_t, uint8_t);
static void nandemulator_read_2(device_t, uint16_t *);
static void nandemulator_write_2(device_t, uint16_t);
static void nandemulator_read_buf_1(device_t, void *, size_t);
static void nandemulator_read_buf_2(device_t, void *, size_t);
static void nandemulator_write_buf_1(device_t, const void *, size_t);
static void nandemulator_write_buf_2(device_t, const void *, size_t);

static size_t nandemulator_address_to_page(device_t);
static size_t nandemulator_page_to_backend_offset(device_t, size_t);
static size_t nandemulator_column_address_to_subpage(device_t);
/*
#define NANDEMULATOR_DEBUG 1

#ifdef NANDEMULATOR_DEBUG
#warning debug enabled
#define DPRINTF(x)      if (nandemulatordebug) printf x
#define DPRINTFN(n,x)   if (nandemulatordebug>(n)) printf x
#else
#error no debug
#define DPRINTF(x)
#define DPRINTFN(n,x)
#endif

#ifdef NANDEMULATOR_DEBUG
int     nandemulatordebug = NANDEMULATOR_DEBUG;
#endif
*/

extern int nanddebug;

enum {
        NANDEMULATOR_8BIT,
        NANDEMULATOR_16BIT
};

struct nandemulator_softc {
        device_t                sc_dev;
        device_t                sc_nanddev;

        int                     sc_buswidth;

        struct nand_interface   sc_nand_if;

        uint8_t                 sc_command;
        size_t                  sc_io_len;
        uint8_t                 *sc_io_pointer;
        uint64_t                sc_address;

        uint8_t                 *sc_backend;
        size_t                  sc_backend_size;
        size_t                  sc_device_size;
        bool                    sc_register_writable;

        uint8_t                 sc_status_register;
        uint8_t                 sc_ids[2];
        uint8_t                 sc_onfi[4];

        size_t                  sc_page_size;
        size_t                  sc_block_size;
        size_t                  sc_spare_size;
        size_t                  sc_lun_size;
        uint8_t                 sc_row_cycles;
        uint8_t                 sc_column_cycles;
        uint64_t                sc_row_mask;

        int                     sc_address_counter;

        struct onfi_parameter_page      *sc_parameter_page;
};

CFATTACH_DECL_NEW(nandemulator, sizeof(struct nandemulator_softc),
    nandemulator_match, nandemulator_attach, nandemulator_detach, NULL);

void
nandemulatorattach(int n)
{
        int i, err;
        cfdata_t cf;

        aprint_debug("nandemulator: requested %d units\n", n);

        err = config_cfattach_attach(nandemulator_cd.cd_name,
            &nandemulator_ca);
        if (err) {
                aprint_error("%s: couldn't register cfattach: %d\n",
                    nandemulator_cd.cd_name, err);
                config_cfdriver_detach(&nandemulator_cd);
                return;
        }
        for (i = 0; i < n; i++) {
                cf = kmem_alloc(sizeof(struct cfdata), KM_SLEEP);
                cf->cf_name = nandemulator_cd.cd_name;
                cf->cf_atname = nandemulator_cd.cd_name;
                cf->cf_unit = i;
                cf->cf_fstate = FSTATE_STAR;

                (void)config_attach_pseudo(cf);
        }
}

/* ARGSUSED */
static int
nandemulator_match(device_t parent, cfdata_t match, void *aux)
{
        /* pseudo device, always attaches */
        return 1;
}

static void
nandemulator_attach(device_t parent, device_t self, void *aux)
{
        struct nandemulator_softc *sc = device_private(self);
        int i;

        aprint_normal_dev(self, "NAND emulator\n");

        sc->sc_dev = self;

        nand_init_interface(&sc->sc_nand_if);

        sc->sc_nand_if.command = &nandemulator_command;
        sc->sc_nand_if.address = &nandemulator_address;
        sc->sc_nand_if.read_buf_1 = &nandemulator_read_buf_1;
        sc->sc_nand_if.read_buf_2 = &nandemulator_read_buf_2;
        sc->sc_nand_if.read_1 = &nandemulator_read_1;
        sc->sc_nand_if.read_2 = &nandemulator_read_2;
        sc->sc_nand_if.write_buf_1 = &nandemulator_write_buf_1;
        sc->sc_nand_if.write_buf_2 = &nandemulator_write_buf_2;
        sc->sc_nand_if.write_1 = &nandemulator_write_1;
        sc->sc_nand_if.write_2 = &nandemulator_write_2;
        sc->sc_nand_if.busy = &nandemulator_busy;

        sc->sc_nand_if.ecc.necc_code_size = 3;
        sc->sc_nand_if.ecc.necc_block_size = 256;

        if (!pmf_device_register1(sc->sc_dev, NULL, NULL, NULL))
                aprint_error_dev(sc->sc_dev,
                    "couldn't establish power handler\n");

        sc->sc_buswidth = NANDEMULATOR_16BIT;   /* 16bit for now */

        /* hardcode these now, make it configurable later */
        sc->sc_device_size = 32 * 1024 * 1024; /* 32MB */
        sc->sc_page_size = 2048;
        sc->sc_block_size = 64;
        sc->sc_lun_size =
            sc->sc_device_size / (sc->sc_page_size * sc->sc_block_size);
        KASSERT(sc->sc_device_size %
            (sc->sc_page_size * sc->sc_block_size) == 0);
        sc->sc_spare_size = 64;

        sc->sc_column_cycles = 2;
        sc->sc_row_cycles = 3;

        /* init the emulator data structures */
        sc->sc_backend_size =
            sc->sc_device_size +
            sc->sc_device_size / sc->sc_page_size * sc->sc_spare_size;

        sc->sc_backend = kmem_alloc(sc->sc_backend_size, KM_SLEEP);
        memset(sc->sc_backend, 0xff, sc->sc_backend_size);

        sc->sc_parameter_page =
            kmem_zalloc(sizeof(struct onfi_parameter_page) * 4, KM_SLEEP);

        struct onfi_parameter_page *opp;
        uint8_t sig[4] = { 'O', 'N', 'F', 'I' };

        for (i = 0; i < 4; i++) {
                opp = &sc->sc_parameter_page[i];

                opp->param_signature = htole32(*(uint32_t *)sig);
                opp->param_pagesize = htole32(sc->sc_page_size);
                opp->param_blocksize = htole32(sc->sc_block_size);
                opp->param_sparesize = htole16(sc->sc_spare_size);
                opp->param_lunsize = htole32(sc->sc_lun_size);
                opp->param_numluns = 1;

                opp->param_manufacturer_id = 0x00;
                memcpy(opp->param_manufacturer,
                    "NETBSD", strlen("NETBSD"));
                memcpy(opp->param_model,
                    "NANDEMULATOR", strlen("NANDEMULATOR"));

                uint16_t features = ONFI_FEATURE_16BIT;
                opp->param_features = htole16(features);

                /* the lower 4 bits contain the row address cycles
                 * the upper 4 bits contain the column address cycles
                 */
                opp->param_addr_cycles = sc->sc_row_cycles;
                opp->param_addr_cycles |= (sc->sc_column_cycles << 4);

                opp->param_integrity_crc = nand_crc16((uint8_t *)opp, 254);
        }

        sc->sc_ids[0] = 0x00;
        sc->sc_ids[1] = 0x00;

        sc->sc_onfi[0] = 'O';
        sc->sc_onfi[1] = 'N';
        sc->sc_onfi[2] = 'F';
        sc->sc_onfi[3] = 'I';

        sc->sc_row_mask = 0x00;
        for (i = 0; i < sc->sc_row_cycles; i++) {
                sc->sc_row_mask <<= 8;
                sc->sc_row_mask |= 0xff;
        }

        nandemulator_device_reset(self);

        sc->sc_nanddev = nand_attach_mi(&sc->sc_nand_if, sc->sc_dev);
}

static int
nandemulator_detach(device_t self, int flags)
{
        struct nandemulator_softc *sc = device_private(self);
        int error;

        aprint_normal_dev(sc->sc_dev, "detaching emulator\n");

        error = config_detach_children(self, flags);
        if (error)
                return error;

        pmf_device_deregister(sc->sc_dev);
        kmem_free(sc->sc_backend, sc->sc_backend_size);
        kmem_free(sc->sc_parameter_page,
            sizeof(struct onfi_parameter_page) * 4);
        return 0;
}

/**
 * bring the emulated device to a known state
 */
static void
nandemulator_device_reset(device_t self)
{
        struct nandemulator_softc *sc = device_private(self);

        DPRINTF(("device reset\n"));

        sc->sc_command = 0;
        sc->sc_register_writable = false;
        sc->sc_io_len = 0;
        sc->sc_io_pointer = NULL;
        sc->sc_address = 0;
        sc->sc_address_counter = 0;

        sc->sc_status_register = ONFI_STATUS_RDY | ONFI_STATUS_WP;
}

static void
nandemulator_address_chip(device_t self)
{
        struct nandemulator_softc *sc = device_private(self);
        size_t page, offset;

        KASSERT(sc->sc_address_counter ==
            sc->sc_column_cycles + sc->sc_row_cycles);

        if (sc->sc_address_counter !=
            sc->sc_column_cycles + sc->sc_row_cycles) {
                aprint_error_dev(self, "incorrect number of address cycles\n");
                aprint_error_dev(self, "cc: %d, rc: %d, ac: %d\n",
                    sc->sc_column_cycles, sc->sc_row_cycles,
                    sc->sc_address_counter);
        }

        page = nandemulator_address_to_page(self);
        offset = sc->sc_page_size * page;

        DPRINTF(("READ/PROGRAM; page: 0x%jx (row addr: 0x%jx)\n",
                (uintmax_t )page,
                (uintmax_t )offset));

        KASSERT(offset < sc->sc_device_size);

        if (offset >= sc->sc_device_size) {
                aprint_error_dev(self, "address > device size!\n");
                sc->sc_io_len = 0;
        } else {
                size_t addr =
                    nandemulator_page_to_backend_offset(self, page);
                size_t pageoff =
                    nandemulator_column_address_to_subpage(self);

                DPRINTF(("subpage: 0x%jx\n", (uintmax_t )pageoff));

                KASSERT(pageoff <
                    sc->sc_page_size + sc->sc_spare_size);
                KASSERT(addr < sc->sc_backend_size);

                sc->sc_io_pointer = sc->sc_backend + addr + pageoff;
                sc->sc_io_len =
                    sc->sc_page_size + sc->sc_spare_size - pageoff;
        }
}

static void
nandemulator_command(device_t self, uint8_t command)
{
        struct nandemulator_softc *sc = device_private(self);
        size_t offset, page;

        sc->sc_command = command;
        sc->sc_register_writable = false;

        DPRINTF(("nandemulator command: 0x%hhx\n", command));

        switch (command) {
        case ONFI_READ_STATUS:
                sc->sc_io_pointer = &sc->sc_status_register;
                sc->sc_io_len = 1;
                break;
        case ONFI_RESET:
                nandemulator_device_reset(self);
                break;
        case ONFI_PAGE_PROGRAM:
                sc->sc_register_writable = true;
                /* FALLTHROUGH */
        case ONFI_READ:
        case ONFI_BLOCK_ERASE:
                sc->sc_address_counter = 0;
                /* FALLTHROUGH */
        case ONFI_READ_ID:
        case ONFI_READ_PARAMETER_PAGE:
                sc->sc_io_len = 0;
                sc->sc_address = 0;
                break;
        case ONFI_PAGE_PROGRAM_START:
                /* XXX the program should only happen here */
                break;
        case ONFI_READ_START:
                nandemulator_address_chip(self);
                break;
        case ONFI_BLOCK_ERASE_START:
                page = nandemulator_address_to_page(self);
                offset = sc->sc_page_size * page;

                KASSERT(offset %
                    (sc->sc_block_size * sc->sc_page_size) == 0);

                KASSERT(offset < sc->sc_device_size);

                if (offset >= sc->sc_device_size) {
                        aprint_error_dev(self, "address > device size!\n");
                } else {
                        size_t addr =
                            nandemulator_page_to_backend_offset(self, page);

                        size_t blocklen =
                            sc->sc_block_size *
                            (sc->sc_page_size + sc->sc_spare_size);

                        KASSERT(addr < sc->sc_backend_size);
                        uint8_t *block = sc->sc_backend + addr;

                        DPRINTF(("erasing block at 0x%jx\n",
                                (uintmax_t )offset));

                        memset(block, 0xff, blocklen);
                }
                sc->sc_io_len = 0;
                break;
        default:
                aprint_error_dev(self,
                    "invalid nand command (0x%hhx)\n", command);
                KASSERT(false);
                sc->sc_io_len = 0;
        }
};

static void
nandemulator_address(device_t self, uint8_t address)
{
        struct nandemulator_softc *sc = device_private(self);

        DPRINTF(("nandemulator_address: %hhx\n", address));

        /**
         * we have to handle read id/parameter page here,
         * as we can read right after giving the address.
         */
        switch (sc->sc_command) {
        case ONFI_READ_ID:
                if (address == 0x00) {
                        sc->sc_io_len = 2;
                        sc->sc_io_pointer = sc->sc_ids;
                } else if (address == 0x20) {
                        sc->sc_io_len = 4;
                        sc->sc_io_pointer = sc->sc_onfi;
                } else {
                        sc->sc_io_len = 0;
                }
                break;
        case ONFI_READ_PARAMETER_PAGE:
                if (address == 0x00) {
                        sc->sc_io_len = sizeof(struct onfi_parameter_page) * 4;
                        sc->sc_io_pointer = (uint8_t *)sc->sc_parameter_page;
                } else {
                        sc->sc_io_len = 0;
                }
                break;
        case ONFI_PAGE_PROGRAM:
                sc->sc_address <<= 8;
                sc->sc_address |= address;
                sc->sc_address_counter++;

                if (sc->sc_address_counter ==
                    sc->sc_column_cycles + sc->sc_row_cycles) {
                        nandemulator_address_chip(self);
                }
                break;
        default:
                sc->sc_address <<= 8;
                sc->sc_address |= address;
                sc->sc_address_counter++;
        }
};

static void
nandemulator_busy(device_t self)
{
#ifdef NANDEMULATOR_DELAYS
        struct nandemulator_softc *sc = device_private(self);

        /* do some delay depending on command */
        switch (sc->sc_command) {
        case ONFI_PAGE_PROGRAM_START:
        case ONFI_BLOCK_ERASE_START:
                DELAY(10);
                break;
        case ONFI_READ_START:
        default:
                DELAY(1);
        }
#endif
}

static void
nandemulator_read_1(device_t self, uint8_t *data)
{
        struct nandemulator_softc *sc = device_private(self);

        KASSERT(sc->sc_io_len > 0);

        if (sc->sc_io_len > 0) {
                *data = *sc->sc_io_pointer;

                sc->sc_io_pointer++;
                sc->sc_io_len--;
        } else {
                aprint_error_dev(self, "reading byte from invalid location\n");
                *data = 0xff;
        }
}

static void
nandemulator_write_1(device_t self, uint8_t data)
{
        struct nandemulator_softc *sc = device_private(self);

        KASSERT(sc->sc_register_writable);

        if (!sc->sc_register_writable) {
                aprint_error_dev(self,
                    "trying to write read only location without effect\n");
                return;
        }

        KASSERT(sc->sc_io_len > 0);

        if (sc->sc_io_len > 0) {
                *sc->sc_io_pointer = data;

                sc->sc_io_pointer++;
                sc->sc_io_len--;
        } else {
                aprint_error_dev(self, "write to invalid location\n");
        }
}

static void
nandemulator_read_2(device_t self, uint16_t *data)
{
        struct nandemulator_softc *sc = device_private(self);

        KASSERT(sc->sc_buswidth == NANDEMULATOR_16BIT);

        if (sc->sc_buswidth != NANDEMULATOR_16BIT) {
                aprint_error_dev(self,
                    "trying to read a word on an 8bit chip\n");
                return;
        }

        KASSERT(sc->sc_io_len > 1);

        if (sc->sc_io_len > 1) {
                *data = *(uint16_t *)sc->sc_io_pointer;

                sc->sc_io_pointer += 2;
                sc->sc_io_len -= 2;
        } else {
                aprint_error_dev(self, "reading word from invalid location\n");
                *data = 0xffff;
        }
}

static void
nandemulator_write_2(device_t self, uint16_t data)
{
        struct nandemulator_softc *sc = device_private(self);

        KASSERT(sc->sc_register_writable);

        if (!sc->sc_register_writable) {
                aprint_error_dev(self,
                    "trying to write read only location without effect\n");
                return;
        }

        KASSERT(sc->sc_buswidth == NANDEMULATOR_16BIT);

        if (sc->sc_buswidth != NANDEMULATOR_16BIT) {
                aprint_error_dev(self,
                    "trying to write a word to an 8bit chip");
                return;
        }

        KASSERT(sc->sc_io_len > 1);

        if (sc->sc_io_len > 1) {
                *(uint16_t *)sc->sc_io_pointer = data;

                sc->sc_io_pointer += 2;
                sc->sc_io_len -= 2;
        } else {
                aprint_error_dev(self, "writing to invalid location");
        }
}

static void
nandemulator_read_buf_1(device_t self, void *buf, size_t len)
{
        uint8_t *addr;

        KASSERT(buf != NULL);
        KASSERT(len >= 1);

        addr = buf;
        while (len > 0) {
                nandemulator_read_1(self, addr);
                addr++, len--;
        }
}

static void
nandemulator_read_buf_2(device_t self, void *buf, size_t len)
{
        uint16_t *addr;

        KASSERT(buf != NULL);
        KASSERT(len >= 2);
        KASSERT(!(len & 0x01));

        addr = buf;
        len /= 2;
        while (len > 0) {
                nandemulator_read_2(self, addr);
                addr++, len--;
        }
}

static void
nandemulator_write_buf_1(device_t self, const void *buf, size_t len)
{
        const uint8_t *addr;

        KASSERT(buf != NULL);
        KASSERT(len >= 1);

        addr = buf;
        while (len > 0) {
                nandemulator_write_1(self, *addr);
                addr++, len--;
        }
}

static void
nandemulator_write_buf_2(device_t self, const void *buf, size_t len)
{
        const uint16_t *addr;

        KASSERT(buf != NULL);
        KASSERT(len >= 2);
        KASSERT(!(len & 0x01));

        addr = buf;
        len /= 2;
        while (len > 0) {
                nandemulator_write_2(self, *addr);
                addr++, len--;
        }
}

static size_t
nandemulator_address_to_page(device_t self)
{
        struct nandemulator_softc *sc = device_private(self);
        uint64_t address, offset;
        int i;

        address = htole64(sc->sc_address);
        address &= sc->sc_row_mask;

        offset = 0;
        for (i = 0; i < sc->sc_row_cycles; i++) {
                offset <<= 8;
                offset |= (address & 0xff);
                address >>= 8;
        }

        return le64toh(offset);
}

static size_t
nandemulator_column_address_to_subpage(device_t self)
{
        struct nandemulator_softc *sc = device_private(self);
        uint64_t address, offset;
        int i;

        address = htole64(sc->sc_address);
        address >>= (8 * sc->sc_row_cycles);

        offset = 0;
        for (i = 0; i < sc->sc_column_cycles; i++) {
                offset <<= 8;
                offset |= (address & 0xff);
                address >>= 8;
        }

        if (sc->sc_buswidth == NANDEMULATOR_16BIT)
                return (size_t )le64toh(offset << 1);
        else
                return (size_t )le64toh(offset);
}

static size_t
nandemulator_page_to_backend_offset(device_t self, size_t page)
{
        struct nandemulator_softc *sc = device_private(self);

        return (sc->sc_page_size + sc->sc_spare_size) * page;
}

#ifdef _MODULE

MODULE(MODULE_CLASS_DRIVER, nandemulator, "nand");

static const struct cfiattrdata nandbuscf_iattrdata = {
        "nandbus", 0, { { NULL, NULL, 0 }, }
};
static const struct cfiattrdata * const nandemulator_attrs[] = {
        &nandbuscf_iattrdata, NULL
};

CFDRIVER_DECL(nandemulator, DV_DULL, nandemulator_attrs);
extern struct cfattach nandemulator_ca;
static int nandemulatorloc[] = { -1, -1 };

static struct cfdata nandemulator_cfdata[] = {
        {
                .cf_name = "nandemulator",
                .cf_atname = "nandemulator",
                .cf_unit = 0,
                .cf_fstate = FSTATE_STAR,
                .cf_loc = nandemulatorloc,
                .cf_flags = 0,
                .cf_pspec = NULL,
        },
        { NULL, NULL, 0, 0, NULL, 0, NULL }
};

static int
nandemulator_modcmd(modcmd_t cmd, void *arg)
{
        int error;

        switch (cmd) {
        case MODULE_CMD_INIT:
                error = config_cfdriver_attach(&nandemulator_cd);
                if (error) {
                        return error;
                }

                error = config_cfattach_attach(nandemulator_cd.cd_name,
                    &nandemulator_ca);
                if (error) {
                        config_cfdriver_detach(&nandemulator_cd);
                        aprint_error("%s: unable to register cfattach\n",
                                nandemulator_cd.cd_name);

                        return error;
                }

                error = config_cfdata_attach(nandemulator_cfdata, 1);
                if (error) {
                        config_cfattach_detach(nandemulator_cd.cd_name,
                            &nandemulator_ca);
                        config_cfdriver_detach(&nandemulator_cd);
                        aprint_error("%s: unable to register cfdata\n",
                                nandemulator_cd.cd_name);

                        return error;
                }

                (void)config_attach_pseudo(nandemulator_cfdata);

                return 0;

        case MODULE_CMD_FINI:
                error = config_cfdata_detach(nandemulator_cfdata);
                if (error) {
                        return error;
                }

                config_cfattach_detach(nandemulator_cd.cd_name,
                    &nandemulator_ca);
                config_cfdriver_detach(&nandemulator_cd);

                return 0;

        case MODULE_CMD_AUTOUNLOAD:
                /* prevent auto-unload */
                return EBUSY;

        default:
                return ENOTTY;
        }
}

#endif