/* $OpenBSD: agp.c,v 1.51 2024/05/24 06:02:53 jsg Exp $ */
/*-
 * Copyright (c) 2000 Doug Rabson
 * All rights reserved.
 *
 * 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.
 *
 *      $FreeBSD: src/sys/pci/agp.c,v 1.12 2001/05/19 01:28:07 alfred Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>

#include <uvm/uvm_extern.h>

#include <dev/pci/pcivar.h>

#include <dev/pci/agpvar.h>
#include <dev/pci/agpreg.h>

void    agp_attach(struct device *, struct device *, void *);
int     agp_probe(struct device *, void *, void *);

int     agpvga_match(struct pci_attach_args *);

int
agpdev_print(void *aux, const char *pnp)
{
        if (pnp) {
                printf("agp at %s", pnp);
        }
        return (UNCONF);
}

int
agpbus_probe(struct agp_attach_args *aa)
{
        struct pci_attach_args  *pa = aa->aa_pa;

        if (strncmp(aa->aa_busname, "agp", 3) == 0 &&
            PCI_CLASS(pa->pa_class) == PCI_CLASS_BRIDGE && 
            PCI_SUBCLASS(pa->pa_class) == PCI_SUBCLASS_BRIDGE_HOST)
                return (1);
        return (0);
}

/*
 * Find the video card hanging off the agp bus XXX assumes only one bus
 */
int
agpvga_match(struct pci_attach_args *pa)
{
        if (PCI_CLASS(pa->pa_class) == PCI_CLASS_DISPLAY &&
            PCI_SUBCLASS(pa->pa_class) == PCI_SUBCLASS_DISPLAY_VGA) {
                if (pci_get_capability(pa->pa_pc, pa->pa_tag, PCI_CAP_AGP,
                    NULL, NULL))
                        return (1);
        }
        return (0);
}

struct device *
agp_attach_bus(struct pci_attach_args *pa, const struct agp_methods *methods,
    bus_addr_t apaddr, bus_size_t apsize, struct device *dev)
{
        struct agpbus_attach_args arg;

        arg.aa_methods = methods;
        arg.aa_pa = pa;
        arg.aa_apaddr = apaddr;
        arg.aa_apsize = apsize;

        printf("\n"); /* newline from the driver that called us */
        return (config_found(dev, &arg, agpdev_print));
}

int
agp_probe(struct device *parent, void *match, void *aux)
{
        /*
         * we don't do any checking here, driver we're attaching this
         * interface to should have already done it.
         */
        return (1);
}

void
agp_attach(struct device *parent, struct device *self, void *aux)
{
        struct agpbus_attach_args *aa = aux;
        struct pci_attach_args *pa = aa->aa_pa;
        struct agp_softc *sc = (struct agp_softc *)self;
        u_int memsize;
        int i;

        sc->sc_chipc = parent;
        sc->sc_methods = aa->aa_methods;
        sc->sc_apaddr = aa->aa_apaddr;
        sc->sc_apsize = aa->aa_apsize;

        static const int agp_max[][2] = {
                {0,             0},
                {32,            4},
                {64,            28},
                {128,           96},
                {256,           204},
                {512,           440},
                {1024,          942},
                {2048,          1920},
                {4096,          3932}
        };

        /*
         * Work out an upper bound for agp memory allocation. This
         * uses a heuristic table from the Linux driver.
         */
        memsize = ptoa(physmem) >> 20;

        for (i = 0; i < nitems(agp_max) && memsize > agp_max[i][0]; i++)
                ;
        if (i == nitems(agp_max))
                i = nitems(agp_max) - 1;
        sc->sc_maxmem = agp_max[i][1] << 20;

        sc->sc_pcitag = pa->pa_tag;
        sc->sc_pc = pa->pa_pc;
        sc->sc_id = pa->pa_id;
        sc->sc_dmat = pa->pa_dmat;
        sc->sc_memt = pa->pa_memt;

        pci_get_capability(sc->sc_pc, sc->sc_pcitag, PCI_CAP_AGP,
            &sc->sc_capoff, NULL);

        printf(": aperture at 0x%lx, size 0x%lx\n", (u_long)sc->sc_apaddr,
            (u_long)sc->sc_apsize);
}

const struct cfattach agp_ca = {
        sizeof(struct agp_softc), agp_probe, agp_attach,
        NULL, NULL
};

struct cfdriver agp_cd = {
        NULL, "agp", DV_DULL
};

struct agp_gatt *
agp_alloc_gatt(bus_dma_tag_t dmat, u_int32_t apsize)
{
        struct agp_gatt         *gatt;
        u_int32_t                entries = apsize >> AGP_PAGE_SHIFT;

        gatt = malloc(sizeof(*gatt), M_AGP, M_NOWAIT | M_ZERO);
        if (!gatt)
                return (NULL);
        gatt->ag_entries = entries;
        gatt->ag_size = entries * sizeof(u_int32_t);

        if (agp_alloc_dmamem(dmat, gatt->ag_size, &gatt->ag_dmamap,
            &gatt->ag_physical, &gatt->ag_dmaseg) != 0) {
                free(gatt, M_AGP, sizeof *gatt);
                return (NULL);
        }

        if (bus_dmamem_map(dmat, &gatt->ag_dmaseg, 1, gatt->ag_size,
            (caddr_t *)&gatt->ag_virtual, BUS_DMA_NOWAIT) != 0) {
                agp_free_dmamem(dmat, gatt->ag_size, gatt->ag_dmamap,
                    &gatt->ag_dmaseg);
                free(gatt, M_AGP, sizeof *gatt);
                return (NULL);
        }

        agp_flush_cache();

        return (gatt);
}

void
agp_free_gatt(bus_dma_tag_t dmat, struct agp_gatt *gatt)
{
        bus_dmamem_unmap(dmat, (caddr_t)gatt->ag_virtual, gatt->ag_size);
        agp_free_dmamem(dmat, gatt->ag_size, gatt->ag_dmamap, &gatt->ag_dmaseg);
        free(gatt, M_AGP, sizeof *gatt);
}

int
agp_generic_enable(struct agp_softc *sc, u_int32_t mode)
{
        struct pci_attach_args  pa;
        pcireg_t                tstatus, mstatus, command;
        int                     rq, sba, fw, rate, capoff;
        
        if (pci_find_device(&pa, agpvga_match) == 0 ||
            pci_get_capability(pa.pa_pc, pa.pa_tag, PCI_CAP_AGP,
            &capoff, NULL) == 0) {
                printf("agp_generic_enable: not an AGP capable device\n");
                return (-1);
        }

        tstatus = pci_conf_read(sc->sc_pc, sc->sc_pcitag,
            sc->sc_capoff + AGP_STATUS);
        /* display agp mode */
        mstatus = pci_conf_read(pa.pa_pc, pa.pa_tag,
            capoff + AGP_STATUS);

        /* Set RQ to the min of mode, tstatus and mstatus */
        rq = AGP_MODE_GET_RQ(mode);
        if (AGP_MODE_GET_RQ(tstatus) < rq)
                rq = AGP_MODE_GET_RQ(tstatus);
        if (AGP_MODE_GET_RQ(mstatus) < rq)
                rq = AGP_MODE_GET_RQ(mstatus);

        /* Set SBA if all three can deal with SBA */
        sba = (AGP_MODE_GET_SBA(tstatus)
            & AGP_MODE_GET_SBA(mstatus)
            & AGP_MODE_GET_SBA(mode));

        /* Similar for FW */
        fw = (AGP_MODE_GET_FW(tstatus)
            & AGP_MODE_GET_FW(mstatus)
            & AGP_MODE_GET_FW(mode));

        /* Figure out the max rate */
        rate = (AGP_MODE_GET_RATE(tstatus)
            & AGP_MODE_GET_RATE(mstatus)
            & AGP_MODE_GET_RATE(mode));
        if (rate & AGP_MODE_RATE_4x)
                rate = AGP_MODE_RATE_4x;
        else if (rate & AGP_MODE_RATE_2x)
                rate = AGP_MODE_RATE_2x;
        else
                rate = AGP_MODE_RATE_1x;

        /* Construct the new mode word and tell the hardware  */
        command = AGP_MODE_SET_RQ(0, rq);
        command = AGP_MODE_SET_SBA(command, sba);
        command = AGP_MODE_SET_FW(command, fw);
        command = AGP_MODE_SET_RATE(command, rate);
        command = AGP_MODE_SET_AGP(command, 1);

        pci_conf_write(sc->sc_pc, sc->sc_pcitag,
            sc->sc_capoff + AGP_COMMAND, command);
        pci_conf_write(pa.pa_pc, pa.pa_tag, capoff + AGP_COMMAND, command);
        return (0);
}

/*
 * Allocates a single-segment block of zeroed, wired dma memory.
 */
int
agp_alloc_dmamem(bus_dma_tag_t tag, size_t size, bus_dmamap_t *mapp,
    bus_addr_t *baddr, bus_dma_segment_t *seg)
{
        int error, level = 0, nseg;

        if ((error = bus_dmamem_alloc(tag, size, PAGE_SIZE, 0,
            seg, 1, &nseg, BUS_DMA_NOWAIT | BUS_DMA_ZERO)) != 0)
                goto out;
        level++;

        if ((error = bus_dmamap_create(tag, size, nseg, size, 0,
            BUS_DMA_NOWAIT, mapp)) != 0)
                goto out;
        level++;

        if ((error = bus_dmamap_load_raw(tag, *mapp, seg, nseg, size,
            BUS_DMA_NOWAIT)) != 0)
                goto out;

        *baddr = (*mapp)->dm_segs[0].ds_addr;

        return (0);
out:
        switch (level) {
        case 2:
                bus_dmamap_destroy(tag, *mapp);
                /* FALLTHROUGH */
        case 1:
                bus_dmamem_free(tag, seg, nseg);
                break;
        default:
                break;
        }

        return (error);
}

void
agp_free_dmamem(bus_dma_tag_t tag, size_t size, bus_dmamap_t map,
    bus_dma_segment_t *seg)
{
        bus_dmamap_unload(tag, map);
        bus_dmamap_destroy(tag, map);
        bus_dmamem_free(tag, seg, 1);
}

/* Implementation of the kernel api */

void *
agp_find_device(int unit)
{
        if (unit >= agp_cd.cd_ndevs || unit < 0)
                return (NULL);
        return (agp_cd.cd_devs[unit]);
}

enum agp_acquire_state
agp_state(void *dev)
{
        struct agp_softc *sc = (struct agp_softc *) dev;
        return (sc->sc_state);
}

void
agp_get_info(void *dev, struct agp_info *info)
{
        struct agp_softc *sc = (struct agp_softc *)dev;

        if (sc->sc_capoff != 0)
                info->ai_mode = pci_conf_read(sc->sc_pc, sc->sc_pcitag,
                    AGP_STATUS + sc->sc_capoff);
        else
                info->ai_mode = 0; /* i810 doesn't have real AGP */
        info->ai_aperture_base = sc->sc_apaddr;
        info->ai_aperture_size = sc->sc_apsize;
        info->ai_memory_allowed = sc->sc_maxmem;
        info->ai_memory_used = sc->sc_allocated;
        info->ai_devid = sc->sc_id;
}

int
agp_acquire(void *dev)
{
        struct agp_softc *sc = (struct agp_softc *)dev;

        if (sc->sc_chipc == NULL) 
                return (EINVAL);

        if (sc->sc_state != AGP_ACQUIRE_FREE)
                return (EBUSY);
        sc->sc_state = AGP_ACQUIRE_KERNEL;

        return (0);
}

int
agp_release(void *dev)
{
        struct agp_softc *sc = (struct agp_softc *)dev;

        if (sc->sc_state == AGP_ACQUIRE_FREE)
                return (0);

        if (sc->sc_state != AGP_ACQUIRE_KERNEL) 
                return (EBUSY);

        sc->sc_state = AGP_ACQUIRE_FREE;
        return (0);
}

int
agp_enable(void *dev, u_int32_t mode)
{
        struct agp_softc        *sc = dev;
        int                      ret;

        if (sc->sc_methods->enable != NULL) {
                ret = sc->sc_methods->enable(sc->sc_chipc, mode);
        } else {
                ret = agp_generic_enable(sc, mode);
        }
        return (ret);
}

paddr_t
agp_mmap(struct agp_softc *sc, off_t off, int prot)
{
        if (sc->sc_chipc == NULL)
                return (-1);

        if (off >= sc->sc_apsize)
                return (-1);

        if (sc->sc_apaddr == 0)
                return (-1);

        return bus_space_mmap(sc->sc_memt, sc->sc_apaddr, off, prot, 0);
}