/*-
 * Copyright 2011 Nathan Whitehorn
 *
 * 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>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/module.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/smp.h>

#include <vm/vm.h>
#include <vm/pmap.h>

#include <machine/bus.h>
#include <machine/intr_machdep.h>
#include <machine/md_var.h>
#include <machine/rtas.h>

#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>

#include "phyp-hvcall.h"
#include "pic_if.h"

#define XICP_PRIORITY	5	/* Random non-zero number */
#define XICP_IPI	2
#define MAX_XICP_IRQS	(1<<24)	/* 24-bit XIRR field */

static int	xicp_probe(device_t);
static int	xicp_attach(device_t);
static int	xics_probe(device_t);
static int	xics_attach(device_t);

static void	xicp_bind(device_t dev, u_int irq, cpuset_t cpumask);
static void	xicp_dispatch(device_t, struct trapframe *);
static void	xicp_enable(device_t, u_int, u_int);
static void	xicp_eoi(device_t, u_int);
static void	xicp_ipi(device_t, u_int);
static void	xicp_mask(device_t, u_int);
static void	xicp_unmask(device_t, u_int);

static device_method_t  xicp_methods[] = {
	/* Device interface */
	DEVMETHOD(device_probe,		xicp_probe),
	DEVMETHOD(device_attach,	xicp_attach),

	/* PIC interface */
	DEVMETHOD(pic_bind,		xicp_bind),
	DEVMETHOD(pic_dispatch,		xicp_dispatch),
	DEVMETHOD(pic_enable,		xicp_enable),
	DEVMETHOD(pic_eoi,		xicp_eoi),
	DEVMETHOD(pic_ipi,		xicp_ipi),
	DEVMETHOD(pic_mask,		xicp_mask),
	DEVMETHOD(pic_unmask,		xicp_unmask),

	{ 0, 0 },
};

static device_method_t  xics_methods[] = {
	/* Device interface */
	DEVMETHOD(device_probe,		xics_probe),
	DEVMETHOD(device_attach,	xics_attach),

	{ 0, 0 },
};

struct xicp_softc {
	struct mtx sc_mtx;

	int ibm_int_on;
	int ibm_int_off;
	int ibm_get_xive;
	int ibm_set_xive;

	/* XXX: inefficient -- hash table? tree? */
	struct {
		int irq;
		int vector;
	} intvecs[256];
	int nintvecs;
};

static driver_t xicp_driver = {
	"xicp",
	xicp_methods,
	sizeof(struct xicp_softc)
};

static driver_t xics_driver = {
	"xics",
	xics_methods,
	0
};

static devclass_t xicp_devclass;
static devclass_t xics_devclass;

EARLY_DRIVER_MODULE(xicp, ofwbus, xicp_driver, xicp_devclass, 0, 0,
    BUS_PASS_INTERRUPT-1);
EARLY_DRIVER_MODULE(xics, ofwbus, xics_driver, xics_devclass, 0, 0,
    BUS_PASS_INTERRUPT);

static int
xicp_probe(device_t dev)
{
	if (ofw_bus_get_name(dev) == NULL || strcmp(ofw_bus_get_name(dev),
	    "interrupt-controller") != 0)
		return (ENXIO);

	if (!ofw_bus_is_compatible(dev, "ibm,ppc-xicp"))
		return (ENXIO);

	device_set_desc(dev, "PAPR virtual interrupt controller");
	return (BUS_PROBE_GENERIC);
}

static int
xics_probe(device_t dev)
{
	if (ofw_bus_get_name(dev) == NULL || strcmp(ofw_bus_get_name(dev),
	    "interrupt-controller") != 0)
		return (ENXIO);

	if (!ofw_bus_is_compatible(dev, "ibm,ppc-xics"))
		return (ENXIO);

	device_set_desc(dev, "PAPR virtual interrupt source");
	return (BUS_PROBE_GENERIC);
}

static int
xicp_attach(device_t dev)
{
	struct xicp_softc *sc = device_get_softc(dev);
	phandle_t phandle = ofw_bus_get_node(dev);

	mtx_init(&sc->sc_mtx, "XICP", NULL, MTX_DEF);
	sc->nintvecs = 0;

	sc->ibm_int_on = rtas_token_lookup("ibm,int-on");
	sc->ibm_int_off = rtas_token_lookup("ibm,int-off");
	sc->ibm_set_xive = rtas_token_lookup("ibm,set-xive");
	sc->ibm_get_xive = rtas_token_lookup("ibm,get-xive");

	if (OF_getproplen(phandle, "ibm,phandle") > 0)
		OF_getprop(phandle, "ibm,phandle", &phandle, sizeof(phandle));

	powerpc_register_pic(dev, phandle, MAX_XICP_IRQS,
	    1 /* Number of IPIs */, FALSE);
	root_pic = dev;

	return (0);
}

static int
xics_attach(device_t dev)
{
	phandle_t phandle = ofw_bus_get_node(dev);

	if (OF_getproplen(phandle, "ibm,phandle") > 0)
		OF_getprop(phandle, "ibm,phandle", &phandle, sizeof(phandle));

	/* The XICP (root PIC) will handle all our interrupts */
	powerpc_register_pic(root_pic, phandle, MAX_XICP_IRQS,
	    1 /* Number of IPIs */, FALSE);

	return (0);
}

/*
 * PIC I/F methods.
 */

static void
xicp_bind(device_t dev, u_int irq, cpuset_t cpumask)
{
	struct xicp_softc *sc = device_get_softc(dev);
	cell_t status, cpu;

	/*
	 * This doesn't appear to actually support affinity groups, so just
	 * use the first CPU.
	 */
	CPU_FOREACH(cpu)
		if (CPU_ISSET(cpu, &cpumask)) break;

	rtas_call_method(sc->ibm_set_xive, 3, 1, irq, cpu, XICP_PRIORITY,
	    &status);
}

static void
xicp_dispatch(device_t dev, struct trapframe *tf)
{
	struct xicp_softc *sc;
	uint64_t xirr, junk;
	int i;

	sc = device_get_softc(dev);
	for (;;) {
		/* Return value in R4, use the PFT call */
		phyp_pft_hcall(H_XIRR, 0, 0, 0, 0, &xirr, &junk, &junk);
		xirr &= 0x00ffffff;

		if (xirr == 0) { /* No more pending interrupts? */
			phyp_hcall(H_CPPR, (uint64_t)0xff);
			break;
		}
		if (xirr == XICP_IPI) {		/* Magic number for IPIs */
			xirr = MAX_XICP_IRQS;	/* Map to FreeBSD magic */
			phyp_hcall(H_IPI, (uint64_t)(PCPU_GET(cpuid)),
			    0xff); /* Clear IPI */
		}

		/* XXX: super inefficient */
		for (i = 0; i < sc->nintvecs; i++) {
			if (sc->intvecs[i].irq == xirr)
				break;
		}

		KASSERT(i < sc->nintvecs, ("Unmapped XIRR"));
		powerpc_dispatch_intr(sc->intvecs[i].vector, tf);
	}
}

static void
xicp_enable(device_t dev, u_int irq, u_int vector)
{
	struct xicp_softc *sc;
	cell_t status, cpu;

	sc = device_get_softc(dev);

	KASSERT(sc->nintvecs + 1 < sizeof(sc->intvecs)/sizeof(sc->intvecs[0]),
	    ("Too many XICP interrupts"));

	mtx_lock(&sc->sc_mtx);
	sc->intvecs[sc->nintvecs].irq = irq;
	sc->intvecs[sc->nintvecs].vector = vector;
	mb();
	sc->nintvecs++;
	mtx_unlock(&sc->sc_mtx);

	/* IPIs are also enabled */
	if (irq == MAX_XICP_IRQS)
		return;

	/* Bind to this CPU to start: distrib. ID is last entry in gserver# */
	cpu = PCPU_GET(cpuid);
	rtas_call_method(sc->ibm_set_xive, 3, 1, irq, cpu, XICP_PRIORITY,
	    &status);
	xicp_unmask(dev, irq);
}

static void
xicp_eoi(device_t dev, u_int irq)
{
	uint64_t xirr;

	if (irq == MAX_XICP_IRQS) /* Remap IPI interrupt to internal value */
		irq = XICP_IPI;
	xirr = irq | (XICP_PRIORITY << 24);

	phyp_hcall(H_EOI, xirr);
}

static void
xicp_ipi(device_t dev, u_int cpu)
{

	phyp_hcall(H_IPI, (uint64_t)cpu, XICP_PRIORITY);
}

static void
xicp_mask(device_t dev, u_int irq)
{
	struct xicp_softc *sc = device_get_softc(dev);
	cell_t status;

	if (irq == MAX_XICP_IRQS)
		return;

	rtas_call_method(sc->ibm_int_off, 1, 1, irq, &status);
}

static void
xicp_unmask(device_t dev, u_int irq)
{
	struct xicp_softc *sc = device_get_softc(dev);
	cell_t status;

	if (irq == MAX_XICP_IRQS)
		return;

	rtas_call_method(sc->ibm_int_on, 1, 1, irq, &status);
}