/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2005 John Baldwin <jhb@FreeBSD.org>
 *
 * 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 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.
 */

/*
 * Simple driver for PCI VGA display devices.  Drivers such as agp(4) and
 * drm(4) should attach as children of this device.
 *
 * XXX: The vgapci name is a hack until we somehow merge the isa vga driver
 * in or rename it.
 */

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/rman.h>
#include <sys/sysctl.h>
#include <sys/systm.h>

#include <machine/pmap.h>

#include <bus/pci/pcireg.h>
#include <bus/pci/pcivar.h>

struct vga_resource {
        struct resource *vr_res;
        int     vr_refs;
};

struct vga_pci_softc {
        device_t        vga_msi_child;  /* Child driver using MSI. */
        struct vga_resource vga_bars[PCIR_MAX_BAR_0 + 1];
        struct vga_resource vga_bios;
};

SYSCTL_DECL(_hw_pci);

static struct vga_resource *lookup_res(struct vga_pci_softc *sc, int rid);
static struct resource *vga_pci_alloc_resource(device_t dev, device_t child,
    int type, int *rid, u_long start, u_long end, u_long count, u_int flags,
    int cpuid);
static int      vga_pci_release_resource(device_t dev, device_t child, int type,
    int rid, struct resource *r);

int vga_pci_default_unit = -1;
TUNABLE_INT("hw.pci.default_vgapci_unit", &vga_pci_default_unit);
SYSCTL_INT(_hw_pci, OID_AUTO, default_vgapci_unit, CTLFLAG_RD,
    &vga_pci_default_unit, -1, "Default VGA-compatible display");

int
vga_pci_is_boot_display(device_t dev)
{
        int unit;
        device_t pcib;
        uint16_t config;

        /* Check that the given device is a video card */
        if ((pci_get_class(dev) != PCIC_DISPLAY &&
            (pci_get_class(dev) != PCIC_OLD ||
             pci_get_subclass(dev) != PCIS_OLD_VGA))) {
                return (0);
        }


        unit = device_get_unit(dev);

        if (vga_pci_default_unit >= 0) {
                /*
                 * The boot display device was determined by a previous
                 * call to this function, or the user forced it using
                 * the hw.pci.default_vgapci_unit tunable.
                 */
                return (vga_pci_default_unit == unit);
        }

        /*
         * The primary video card used as a boot display must have the
         * "I/O" and "Memory Address Space Decoding" bits set in its
         * Command register.
         *
         * Furthermore, if the card is attached to a bridge, instead of
         * the root PCI bus, the bridge must have the "VGA Enable" bit
         * set in its Control register.
         */

        pcib = device_get_parent(device_get_parent(dev));
        if (device_get_devclass(device_get_parent(pcib)) ==
            devclass_find("pci")) {
                /*
                 * The parent bridge is a PCI-to-PCI bridge: check the
                 * value of the "VGA Enable" bit.
                 */
                config = pci_read_config(pcib, PCIR_BRIDGECTL_1, 2);
                if ((config & PCIB_BCR_VGA_ENABLE) == 0) {
                        return (0);
                }
        }

        config = pci_read_config(dev, PCIR_COMMAND, 2);
        if ((config & (PCIM_CMD_PORTEN | PCIM_CMD_MEMEN)) == 0) {
                return (0);
        }

        /*
         * Disable interrupts until a chipset driver is loaded for
         * this PCI device. Else unhandled display adapter interrupts
         * might freeze the CPU.
         */
        pci_write_config(dev, PCIR_COMMAND, config | PCIM_CMD_INTxDIS, 2);

        /* This video card is the boot display: record its unit number. */
        vga_pci_default_unit = unit;
        device_set_flags(dev, 1);

        return (1);
}

static void
vga_pci_reset(device_t dev)
{
        int ps;
        /*
         * FLR is unsupported on GPUs so attempt a power-management reset by cycling
         * the device in/out of D3 state.
         * PCI spec says we can only go into D3 state from D0 state.
         * Transition from D[12] into D0 before going to D3 state.
         */
        ps = pci_get_powerstate(dev);
        if (ps != PCI_POWERSTATE_D0 && ps != PCI_POWERSTATE_D3)
                pci_set_powerstate(dev, PCI_POWERSTATE_D0);
        if (pci_get_powerstate(dev) != PCI_POWERSTATE_D3)
                pci_set_powerstate(dev, PCI_POWERSTATE_D3);
        pci_set_powerstate(dev, ps);
}

void *
vga_pci_map_bios(device_t dev, size_t *size)
{
        struct vga_resource *vr;
        struct resource *res;
        device_t pcib;
        uint32_t rom_addr;
        uint16_t config;
        volatile unsigned char *bios;
        int i, rid, found;

#if defined(__amd64__) || defined(__i386__)
        if (vga_pci_is_boot_display(dev)) {
                /*
                 * On x86, the System BIOS copy the default display
                 * device's Video BIOS at a fixed location in system
                 * memory (0xC0000, 128 kBytes long) at boot time.
                 *
                 * We use this copy for the default boot device, because
                 * the original ROM may not be valid after boot.
                 */

                *size = VGA_PCI_BIOS_SHADOW_SIZE;
                return (pmap_mapbios(VGA_PCI_BIOS_SHADOW_ADDR, *size));
        }
#endif

        pcib = device_get_parent(device_get_parent(dev));
        if (device_get_devclass(device_get_parent(pcib)) ==
            devclass_find("pci")) {
                /*
                 * The parent bridge is a PCI-to-PCI bridge: check the
                 * value of the "VGA Enable" bit.
                 */
                config = pci_read_config(pcib, PCIR_BRIDGECTL_1, 2);
                if ((config & PCIB_BCR_VGA_ENABLE) == 0) {
                        config |= PCIB_BCR_VGA_ENABLE;
                        pci_write_config(pcib, PCIR_BRIDGECTL_1, config, 2);
                }
        }

        switch(pci_read_config(dev, PCIR_HDRTYPE, 1)) {
        case PCIM_HDRTYPE_BRIDGE:
                rid = PCIR_BIOS_1;
                break;
        case PCIM_HDRTYPE_CARDBUS:
                rid = 0;
                break;
        default:
                rid = PCIR_BIOS;
                break;
        }
        if (rid == 0)
                return (NULL);
        res = vga_pci_alloc_resource(dev, NULL, SYS_RES_MEMORY, &rid, 0,
            ~0, 1, RF_ACTIVE, -1);

        if (res == NULL) {
                device_printf(dev, "vga_pci_alloc_resource failed\n");
                return (NULL);
        }

        bios = rman_get_virtual(res);
        *size = rman_get_size(res);
        for (found = i = 0; i < hz; i++) {
                found = (bios[0] == 0x55 && bios[1] == 0xaa);
                if (found)
                        break;
                tsleep(vga_pci_map_bios, 0, "dummyvgabios", 1);
        }
        if (found)
                return (__DEVOLATILE(void *, bios));
        if (bootverbose)
                device_printf(dev, "initial ROM mapping failed -- resetting\n");

        /*
         * Enable ROM decode
         */
        vga_pci_reset(dev);
        rom_addr = pci_read_config(dev, rid, 4);
        rom_addr &= 0x7ff;
        rom_addr |= rman_get_start(res) | 0x1;
        pci_write_config(dev, rid, rom_addr, 4);
        vr = lookup_res(device_get_softc(dev), rid);
        vga_pci_release_resource(dev, NULL, SYS_RES_MEMORY, rid,
            vr->vr_res);

        /*
         * re-allocate
         */
        res = vga_pci_alloc_resource(dev, NULL, SYS_RES_MEMORY, &rid, 0,
            ~0, 1, RF_ACTIVE, -1);
        if (res == NULL) {
                device_printf(dev, "vga_pci_alloc_resource failed\n");
                return (NULL);
        }
        bios = rman_get_virtual(res);
        *size = rman_get_size(res);

        for (found = i = 0; i < 3*hz; i++) {
                found = (bios[0] == 0x55 && bios[1] == 0xaa);
                if (found)
                        break;
                tsleep(vga_pci_map_bios, 0, "dummyvgabios", 1);
        }
        if (found)
                return (__DEVOLATILE(void *, bios));
        device_printf(dev, "ROM mapping failed\n");
        vr = lookup_res(device_get_softc(dev), rid);
        vga_pci_release_resource(dev, NULL, SYS_RES_MEMORY, rid,
            vr->vr_res);
        return (NULL);
}

void
vga_pci_unmap_bios(device_t dev, void *bios)
{
        struct vga_resource *vr;
        int rid;

        if (bios == NULL) {
                return;
        }

#if defined(__amd64__) || defined(__i386__)
        if (vga_pci_is_boot_display(dev)) {
                /* We mapped the BIOS shadow copy located at 0xC0000. */
                pmap_unmapdev((vm_offset_t)bios, VGA_PCI_BIOS_SHADOW_SIZE);

                return;
        }
#endif
        switch(pci_read_config(dev, PCIR_HDRTYPE, 1)) {
        case PCIM_HDRTYPE_BRIDGE:
                rid = PCIR_BIOS_1;
                break;
        case PCIM_HDRTYPE_CARDBUS:
                rid = 0;
                break;
        default:
                rid = PCIR_BIOS;
                break;
        }
        if (rid == 0)
                return;

        /*
         * Look up the PCIR_BIOS resource in our softc.  It should match
         * the address we returned previously.
         */
        vr = lookup_res(device_get_softc(dev), rid);
        KASSERT(vr->vr_res != NULL, ("vga_pci_unmap_bios: bios not mapped"));
        KASSERT(rman_get_virtual(vr->vr_res) == bios,
            ("vga_pci_unmap_bios: mismatch"));
        vga_pci_release_resource(dev, NULL, SYS_RES_MEMORY, rid,
            vr->vr_res);
}

static int
vga_pci_probe(device_t dev)
{

        switch (pci_get_class(dev)) {
        case PCIC_DISPLAY:
                break;
        case PCIC_OLD:
                if (pci_get_subclass(dev) != PCIS_OLD_VGA)
                        return (ENXIO);
                break;
        default:
                return (ENXIO);
        }

        /* Probe default display. */
        vga_pci_is_boot_display(dev);

        device_set_desc(dev, "VGA-compatible display");
        return (BUS_PROBE_GENERIC);
}

static int
vga_pci_attach(device_t dev)
{

        bus_generic_probe(dev);

        /* Always create a drm child for now to make it easier on drm. */
        device_add_child(dev, "drm", -1);
        bus_generic_attach(dev);

        if (vga_pci_is_boot_display(dev))
                device_printf(dev, "Boot video device\n");

        return (0);
}

static int
vga_pci_suspend(device_t dev)
{

        return (bus_generic_suspend(dev));
}

static int
vga_pci_detach(device_t dev)
{
        int error;

        error = bus_generic_detach(dev);
        if (error == 0)
                error = device_delete_children(dev);
        return (error);
}

static int
vga_pci_resume(device_t dev)
{

        return (bus_generic_resume(dev));
}

/* Bus interface. */

static int
vga_pci_read_ivar(device_t dev, device_t child, int which, uintptr_t *result)
{

        return (BUS_READ_IVAR(device_get_parent(dev), dev, which, result));
}

static int
vga_pci_write_ivar(device_t dev, device_t child, int which, uintptr_t value)
{

        return (EINVAL);
}

static int
vga_pci_setup_intr(device_t dev, device_t child, struct resource *irq,
    int flags, driver_intr_t *intr, void *arg, void **cookiep,
    lwkt_serialize_t serializer, const char *desc)
{

        return (BUS_SETUP_INTR(device_get_parent(dev), dev, irq, flags,
            intr, arg, cookiep, serializer, desc));
}

static int
vga_pci_teardown_intr(device_t dev, device_t child, struct resource *irq,
    void *cookie)
{

        return (BUS_TEARDOWN_INTR(device_get_parent(dev), dev, irq, cookie));
}

static struct vga_resource *
lookup_res(struct vga_pci_softc *sc, int rid)
{
        int bar;

        if (rid == PCIR_BIOS)
                return (&sc->vga_bios);
        bar = PCI_RID2BAR(rid);
        if (bar >= 0 && bar <= PCIR_MAX_BAR_0)
                return (&sc->vga_bars[bar]);
        return (NULL);
}

static struct resource *
vga_pci_alloc_resource(device_t dev, device_t child, int type, int *rid,
    u_long start, u_long end, u_long count, u_int flags, int cpuid __unused)
{
        struct vga_resource *vr;

        switch (type) {
        case SYS_RES_MEMORY:
        case SYS_RES_IOPORT:
                /*
                 * For BARs, we cache the resource so that we only allocate it
                 * from the PCI bus once.
                 */
                vr = lookup_res(device_get_softc(dev), *rid);
                if (vr == NULL)
                        return (NULL);
                if (vr->vr_res == NULL)
                        vr->vr_res = bus_alloc_resource(dev, type, rid, start,
                            end, count, flags);
                if (vr->vr_res != NULL)
                        vr->vr_refs++;
                return (vr->vr_res);
        }
        return (bus_alloc_resource(dev, type, rid, start, end, count, flags));
}

static int
vga_pci_release_resource(device_t dev, device_t child, int type, int rid,
    struct resource *r)
{
        struct vga_resource *vr;
        int error;

        switch (type) {
        case SYS_RES_MEMORY:
        case SYS_RES_IOPORT:
                /*
                 * For BARs, we release the resource from the PCI bus
                 * when the last child reference goes away.
                 */
                vr = lookup_res(device_get_softc(dev), rid);
                if (vr == NULL)
                        return (EINVAL);
                if (vr->vr_res == NULL)
                        return (EINVAL);
                KASSERT(vr->vr_res == r, ("vga_pci resource mismatch"));
                if (vr->vr_refs > 1) {
                        vr->vr_refs--;
                        return (0);
                }
                KASSERT(vr->vr_refs > 0,
                    ("vga_pci resource reference count underflow"));
                error = bus_release_resource(dev, type, rid, r);
                if (error == 0) {
                        vr->vr_res = NULL;
                        vr->vr_refs = 0;
                }
                return (error);
        }

        return (bus_release_resource(dev, type, rid, r));
}

/* PCI interface. */

static uint32_t
vga_pci_read_config(device_t dev, device_t child, int reg, int width)
{

        return (pci_read_config(dev, reg, width));
}

static void
vga_pci_write_config(device_t dev, device_t child, int reg,
    uint32_t val, int width)
{

        pci_write_config(dev, reg, val, width);
}

static int
vga_pci_enable_busmaster(device_t dev, device_t child)
{

        return (pci_enable_busmaster(dev));
}

static int
vga_pci_disable_busmaster(device_t dev, device_t child)
{

        return (pci_disable_busmaster(dev));
}

static int
vga_pci_enable_io(device_t dev, device_t child, int space)
{

        device_printf(dev, "child %s requested pci_enable_io\n",
            device_get_nameunit(child));
        return (pci_enable_io(dev, space));
}

static int
vga_pci_disable_io(device_t dev, device_t child, int space)
{

        device_printf(dev, "child %s requested pci_disable_io\n",
            device_get_nameunit(child));
        return (pci_disable_io(dev, space));
}

static int
vga_pci_get_vpd_ident(device_t dev, device_t child, const char **identptr)
{

        return (pci_get_vpd_ident(dev, identptr));
}

static int
vga_pci_get_vpd_readonly(device_t dev, device_t child, const char *kw,
    const char **vptr)
{

        return (pci_get_vpd_readonly(dev, kw, vptr));
}

static int
vga_pci_set_powerstate(device_t dev, device_t child, int state)
{

        device_printf(dev, "child %s requested pci_set_powerstate\n",
            device_get_nameunit(child));
        return (pci_set_powerstate(dev, state));
}

static int
vga_pci_get_powerstate(device_t dev, device_t child)
{

        device_printf(dev, "child %s requested pci_get_powerstate\n",
            device_get_nameunit(child));
        return (pci_get_powerstate(dev));
}

static int
vga_pci_assign_interrupt(device_t dev, device_t child)
{

        device_printf(dev, "child %s requested pci_assign_interrupt\n",
            device_get_nameunit(child));
        return (PCI_ASSIGN_INTERRUPT(device_get_parent(dev), dev));
}

static int
vga_pci_find_extcap(device_t dev, device_t child, int capability,
    int *capreg)
{

        return (pci_find_extcap(dev, capability, capreg));
}

static int
vga_pci_alloc_msi(device_t dev, device_t child, int *rid, int count,
    int cpuid)
{
        struct vga_pci_softc *sc;
        int error;

        sc = device_get_softc(dev);
        if (sc->vga_msi_child != NULL)
                return (EBUSY);
        error = pci_alloc_msi(dev, rid, count, cpuid);
        if (error == 0)
                sc->vga_msi_child = child;
        return (error);
}

static int
vga_pci_release_msi(device_t dev, device_t child)
{
        struct vga_pci_softc *sc;
        int error;

        sc = device_get_softc(dev);
        if (sc->vga_msi_child != child)
                return (ENXIO);
        error = pci_release_msi(dev);
        if (error == 0)
                sc->vga_msi_child = NULL;
        return (error);
}

static int
vga_pci_msi_count(device_t dev, device_t child)
{

        return (pci_msi_count(dev));
}

static device_method_t vga_pci_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         vga_pci_probe),
        DEVMETHOD(device_attach,        vga_pci_attach),
        DEVMETHOD(device_shutdown,      bus_generic_shutdown),
        DEVMETHOD(device_suspend,       vga_pci_suspend),
        DEVMETHOD(device_detach,        vga_pci_detach),
        DEVMETHOD(device_resume,        vga_pci_resume),

        /* Bus interface */
        DEVMETHOD(bus_read_ivar,        vga_pci_read_ivar),
        DEVMETHOD(bus_write_ivar,       vga_pci_write_ivar),
        DEVMETHOD(bus_setup_intr,       vga_pci_setup_intr),
        DEVMETHOD(bus_teardown_intr,    vga_pci_teardown_intr),

        DEVMETHOD(bus_alloc_resource,   vga_pci_alloc_resource),
        DEVMETHOD(bus_release_resource, vga_pci_release_resource),
        DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
        DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),

        /* PCI interface */
        DEVMETHOD(pci_read_config,      vga_pci_read_config),
        DEVMETHOD(pci_write_config,     vga_pci_write_config),
        DEVMETHOD(pci_enable_busmaster, vga_pci_enable_busmaster),
        DEVMETHOD(pci_disable_busmaster, vga_pci_disable_busmaster),
        DEVMETHOD(pci_enable_io,        vga_pci_enable_io),
        DEVMETHOD(pci_disable_io,       vga_pci_disable_io),
        DEVMETHOD(pci_get_vpd_ident,    vga_pci_get_vpd_ident),
        DEVMETHOD(pci_get_vpd_readonly, vga_pci_get_vpd_readonly),
        DEVMETHOD(pci_get_powerstate,   vga_pci_get_powerstate),
        DEVMETHOD(pci_set_powerstate,   vga_pci_set_powerstate),
        DEVMETHOD(pci_assign_interrupt, vga_pci_assign_interrupt),
        DEVMETHOD(pci_find_extcap,      vga_pci_find_extcap),
        DEVMETHOD(pci_alloc_msi,        vga_pci_alloc_msi),
        DEVMETHOD(pci_release_msi,      vga_pci_release_msi),
        DEVMETHOD(pci_msi_count,        vga_pci_msi_count),

        DEVMETHOD_END
};

static driver_t vga_pci_driver = {
        "vgapci",
        vga_pci_methods,
        sizeof(struct vga_pci_softc),
};

static devclass_t vga_devclass;

DRIVER_MODULE(vgapci, pci, vga_pci_driver, vga_devclass, NULL, NULL);