/*-
 * Copyright (c) 2012 Robert N. M. Watson
 * All rights reserved.
 *
 * This software was 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 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>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/condvar.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/rman.h>
#include <sys/stat.h>
#include <sys/systm.h>
#include <sys/uio.h>

#include <machine/bus.h>
#include <machine/resource.h>
#include <machine/vm.h>

#include <vm/vm.h>

#include <dev/altera/avgen/altera_avgen.h>

/*
 * Generic device driver for allowing read(), write(), and mmap() on
 * memory-mapped, Avalon-attached devices.  There is no actual dependence on
 * Avalon, so conceivably this should just be soc_dev or similar, since many
 * system-on-chip bus environments would work fine with the same code.
 */

static d_mmap_t altera_avgen_mmap;
static d_read_t altera_avgen_read;
static d_write_t altera_avgen_write;

static struct cdevsw avg_cdevsw = {
	.d_version =	D_VERSION,
	.d_mmap =	altera_avgen_mmap,
	.d_read =	altera_avgen_read,
	.d_write =	altera_avgen_write,
	.d_name =	"altera_avgen",
};

static int
altera_avgen_read(struct cdev *dev, struct uio *uio, int flag)
{
	struct altera_avgen_softc *sc;
	u_long offset, size;
#ifdef NOTYET
	uint64_t v8;
#endif
	uint32_t v4;
	uint16_t v2;
	uint8_t v1;
	u_int width;
	int error;

	sc = dev->si_drv1;
	if ((sc->avg_flags & ALTERA_AVALON_FLAG_READ) == 0)
		return (EACCES);
	width = sc->avg_width;
	if (uio->uio_offset < 0 || uio->uio_offset % width != 0 ||
	    uio->uio_resid % width != 0)
		return (ENODEV);
	size = rman_get_size(sc->avg_res);
	if ((uio->uio_offset + uio->uio_resid < 0) ||
	    (uio->uio_offset + uio->uio_resid > size))
		return (ENODEV);
	while (uio->uio_resid > 0) {
		offset = uio->uio_offset;
		if (offset + width > size)
			return (ENODEV);
		switch (width) {
		case 1:
			v1 = bus_read_1(sc->avg_res, offset);
			error = uiomove(&v1, sizeof(v1), uio);
			break;
			
		case 2:
			v2 = bus_read_2(sc->avg_res, offset);
			error = uiomove(&v2, sizeof(v2), uio);
			break;
			
		case 4:
			v4 = bus_read_4(sc->avg_res, offset);
			error = uiomove(&v4, sizeof(v4), uio);
			break;
			
#ifdef NOTYET
		case 8:
			v8 = bus_read_8(sc->avg_res, offset);
			error = uiomove(&v8, sizeof(v8), uio);
			break;
			
#endif

		default:
			panic("%s: unexpected widthment %u", __func__, width);
		}
		if (error)
			return (error);
	}
	return (0);
}

static int
altera_avgen_write(struct cdev *dev, struct uio *uio, int flag)
{
	struct altera_avgen_softc *sc;
	u_long offset, size;
#ifdef NOTYET
	uint64_t v8;
#endif
	uint32_t v4;
	uint16_t v2;
	uint8_t v1;
	u_int width;
	int error;

	sc = dev->si_drv1;
	if ((sc->avg_flags & ALTERA_AVALON_FLAG_WRITE) == 0)
		return (EACCES);
	width = sc->avg_width;
	if (uio->uio_offset < 0 || uio->uio_offset % width != 0 ||
	    uio->uio_resid % width != 0)
		return (ENODEV);
	size = rman_get_size(sc->avg_res);
	while (uio->uio_resid > 0) {
		offset = uio->uio_offset;
		if (offset + width > size)
			return (ENODEV);
		switch (width) {
		case 1:
			error = uiomove(&v1, sizeof(v1), uio);
			if (error)
				return (error);
			bus_write_1(sc->avg_res, offset, v1);
			break;

		case 2:
			error = uiomove(&v2, sizeof(v2), uio);
			if (error)
				return (error);
			bus_write_2(sc->avg_res, offset, v2);
			break;

		case 4:
			error = uiomove(&v4, sizeof(v4), uio);
			if (error)
				return (error);
			bus_write_4(sc->avg_res, offset, v4);
			break;

#ifdef NOTYET
		case 8:
			error = uiomove(&v8, sizeof(v8), uio);
			if (error)
				return (error);
			bus_write_8(sc->avg_res, offset, v8);
			break;
#endif

		default:
			panic("%s: unexpected width %u", __func__, width);
		}
	}
	return (0);
}

static int
altera_avgen_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
    int nprot, vm_memattr_t *memattr)
{
	struct altera_avgen_softc *sc;

	sc = dev->si_drv1;
	if (nprot & VM_PROT_READ) {
		if ((sc->avg_flags & ALTERA_AVALON_FLAG_MMAP_READ) == 0)
			return (EACCES);
	}
	if (nprot & VM_PROT_WRITE) {
		if ((sc->avg_flags & ALTERA_AVALON_FLAG_MMAP_WRITE) == 0)
			return (EACCES);
	}
	if (nprot & VM_PROT_EXECUTE) {
		if ((sc->avg_flags & ALTERA_AVALON_FLAG_MMAP_EXEC) == 0)
			return (EACCES);
	}
	if (trunc_page(offset) == offset &&
	    rman_get_size(sc->avg_res) >= offset + PAGE_SIZE) {
		*paddr = rman_get_start(sc->avg_res) + offset;
		*memattr = VM_MEMATTR_UNCACHEABLE;
	} else
		return (ENODEV);
	return (0);
}

static int
altera_avgen_nexus_probe(device_t dev)
{

	device_set_desc(dev, "Generic Altera Avalon device attachment");
	return (BUS_PROBE_DEFAULT);
}

static int
altera_avgen_process_options(struct altera_avgen_softc *sc,
    const char *str_fileio, const char *str_mmapio, const char *str_devname,
    int devunit)
{
	const char *cp;
	device_t dev = sc->avg_dev;

	/*
	 * Check for valid combinations of options.
	 */
	if (str_fileio == NULL && str_mmapio == NULL) {
		device_printf(dev,
		    "at least one of %s or %s must be specified\n",
		    ALTERA_AVALON_STR_FILEIO, ALTERA_AVALON_STR_MMAPIO);
		return (ENXIO);
	}
	if (str_devname == NULL && devunit != -1) {
		device_printf(dev, "%s requires %s be specified\n",
		    ALTERA_AVALON_STR_DEVUNIT, ALTERA_AVALON_STR_DEVNAME);
		return (ENXIO);
	}

	/*
	 * Extract, digest, and save values.
	 */
	switch (sc->avg_width) {
	case 1:
	case 2:
	case 4:
#ifdef NOTYET
	case 8:
#endif
		break;

	default:
		device_printf(dev, "%s unsupported value %u\n",
		    ALTERA_AVALON_STR_WIDTH, sc->avg_width);
		return (ENXIO);
	}
	sc->avg_flags = 0;
	if (str_fileio != NULL) {
		for (cp = str_fileio; *cp != '\0'; cp++) {
			switch (*cp) {
			case ALTERA_AVALON_CHAR_READ:
				sc->avg_flags |= ALTERA_AVALON_FLAG_READ;
				break;

			case ALTERA_AVALON_CHAR_WRITE:
				sc->avg_flags |= ALTERA_AVALON_FLAG_WRITE;
				break;

			default:
				device_printf(dev,
				    "invalid %s character %c\n", 
				    ALTERA_AVALON_STR_FILEIO, *cp);
				return (ENXIO);
			}
		}
	}
	if (str_mmapio != NULL) {
		for (cp = str_mmapio; *cp != '\0'; cp++) {
			switch (*cp) {
			case ALTERA_AVALON_CHAR_READ:
				sc->avg_flags |= ALTERA_AVALON_FLAG_MMAP_READ;
				break;

			case ALTERA_AVALON_CHAR_WRITE:
				sc->avg_flags |=
				    ALTERA_AVALON_FLAG_MMAP_WRITE;
				break;

			case ALTERA_AVALON_CHAR_EXEC:
				sc->avg_flags |= ALTERA_AVALON_FLAG_MMAP_EXEC;
				break;

			default:
				device_printf(dev,
				    "invalid %s character %c\n",
				    ALTERA_AVALON_STR_MMAPIO, *cp);
				return (ENXIO);
			}
		}
	}
	return (0);
}

static int
altera_avgen_nexus_attach(device_t dev)
{
	struct altera_avgen_softc *sc;
	const char *str_fileio, *str_mmapio;
	const char *str_devname;
	char devname[SPECNAMELEN + 1];
	int devunit, error;

	sc = device_get_softc(dev);
	sc->avg_dev = dev;
	sc->avg_unit = device_get_unit(dev);

	/*
	 * Query non-standard hints to find out what operations are permitted
	 * on the device, and whether it is cached.
	 */
	str_fileio = NULL;
	str_mmapio = NULL;
	str_devname = NULL;
	devunit = -1;
	sc->avg_width = 1;
	error = resource_int_value(device_get_name(dev), device_get_unit(dev),
	    ALTERA_AVALON_STR_WIDTH, &sc->avg_width);
	if (error != 0 && error != ENOENT) {
		device_printf(dev, "invalid %s\n", ALTERA_AVALON_STR_WIDTH);
		return (error);
	}
	(void)resource_string_value(device_get_name(dev),
	    device_get_unit(dev), ALTERA_AVALON_STR_FILEIO, &str_fileio);
	(void)resource_string_value(device_get_name(dev),
	    device_get_unit(dev), ALTERA_AVALON_STR_MMAPIO, &str_mmapio);
	(void)resource_string_value(device_get_name(dev),
	    device_get_unit(dev), ALTERA_AVALON_STR_DEVNAME, &str_devname);
	(void)resource_int_value(device_get_name(dev), device_get_unit(dev),
	    ALTERA_AVALON_STR_DEVUNIT, &devunit);
	error = altera_avgen_process_options(sc, str_fileio, str_mmapio,
	    str_devname, devunit);
	if (error)
		return (error);

	/* Select a device name. */
	if (str_devname != NULL) {
		if (devunit != -1)
			(void)snprintf(devname, sizeof(devname), "%s%d",
			    str_devname, devunit);
		else
			(void)snprintf(devname, sizeof(devname), "%s",
			    str_devname);
	} else
		snprintf(devname, sizeof(devname), "%s%d", "avgen",
		    sc->avg_unit);

	/* Memory allocation and checking. */
	sc->avg_rid = 0;
	sc->avg_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY,
	    &sc->avg_rid, RF_ACTIVE);
	if (sc->avg_res == NULL) {
		device_printf(dev, "couldn't map memory\n");
		return (ENXIO);
	}
	if (rman_get_size(sc->avg_res) >= PAGE_SIZE || str_mmapio != NULL) {
		if (rman_get_size(sc->avg_res) % PAGE_SIZE != 0) {
			device_printf(dev,
			    "memory region not even multiple of page size\n");
			error = ENXIO;
			goto error;
		}
		if (rman_get_start(sc->avg_res) % PAGE_SIZE != 0) {
			device_printf(dev, "memory region not page-aligned\n");
			error = ENXIO;
			goto error;
		}
	}

	/* Device node allocation. */
	if (str_devname == NULL) {
		str_devname = "altera_avgen%d";
		devunit = sc->avg_unit;
	}
	if (devunit != -1)
		sc->avg_cdev = make_dev(&avg_cdevsw, sc->avg_unit, UID_ROOT,
		    GID_WHEEL, S_IRUSR | S_IWUSR, str_devname, devunit);
	else
		sc->avg_cdev = make_dev(&avg_cdevsw, sc->avg_unit, UID_ROOT,
		    GID_WHEEL, S_IRUSR | S_IWUSR, str_devname);
	if (sc->avg_cdev == NULL) {
		device_printf(sc->avg_dev, "%s: make_dev failed\n", __func__);
		error = ENXIO;
		goto error;
	}
	/* XXXRW: Slight race between make_dev(9) and here. */
	sc->avg_cdev->si_drv1 = sc;
	return (0);

error:
	bus_release_resource(dev, SYS_RES_MEMORY, sc->avg_rid, sc->avg_res);
	return (error);
}

static int
altera_avgen_nexus_detach(device_t dev)
{
	struct altera_avgen_softc *sc;

	sc = device_get_softc(dev);
	destroy_dev(sc->avg_cdev);
	bus_release_resource(dev, SYS_RES_MEMORY, sc->avg_rid, sc->avg_res);
	return (0);
}

static device_method_t altera_avgen_nexus_methods[] = {
	DEVMETHOD(device_probe,		altera_avgen_nexus_probe),
	DEVMETHOD(device_attach,	altera_avgen_nexus_attach),
	DEVMETHOD(device_detach,	altera_avgen_nexus_detach),
	{ 0, 0 }
};

static driver_t altera_avgen_nexus_driver = {
	"altera_avgen",
	altera_avgen_nexus_methods,
	sizeof(struct altera_avgen_softc),
};

static devclass_t altera_avgen_devclass;

DRIVER_MODULE(avgen, nexus, altera_avgen_nexus_driver, altera_avgen_devclass,
    0, 0);