/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2020 OmniOS Community Edition (OmniOSce) Association.
 * Copyright 2022 Oxide Computer Company
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/sunndi.h>
#include <sys/pci.h>
#include <sys/pci_impl.h>
#include <sys/pci_cfgspace.h>
#include <sys/pci_cfgspace_impl.h>
#include <sys/memlist.h>
#include <sys/bootconf.h>
#include <sys/psw.h>

/*
 * pci irq routing information table
 */
int                             pci_irq_nroutes;
static pci_irq_route_t          *pci_irq_routes;


static int pci_bios_get_irq_routing(pci_irq_route_t *, int, int *);
static void pci_get_irq_routing_table(void);


/*
 * Retrieve information from the bios needed for system
 * configuration early during startup.
 */
void
startup_pci_bios(void)
{
        pci_get_irq_routing_table();
}


/*
 * Issue the bios get irq routing information table interrupt
 *
 * Despite the name, the information in the table is only
 * used to derive slot names for some named pci hot-plug slots.
 *
 * Returns the number of irq routing table entries returned
 * by the bios, or 0 and optionally, the number of entries required.
 */
static int
pci_bios_get_irq_routing(pci_irq_route_t *routes, int nroutes, int *nneededp)
{
        struct bop_regs regs;
        uchar_t         *hdrp;
        uchar_t         *bufp;
        int             i, n;
        int             rval = 0;

        if (nneededp)
                *nneededp = 0;

        /* in UEFI system, there is no BIOS data */
        if (BOP_GETPROPLEN(bootops, "efi-systab") > 0)
                return (0);

        /*
         * Set up irq routing header with the size and address
         * of some useable low-memory data addresses.  Initalize
         * data area to zero, avoiding memcpy/bzero.
         */
        hdrp = (uchar_t *)BIOS_IRQ_ROUTING_HDR;
        bufp = (uchar_t *)BIOS_IRQ_ROUTING_DATA;

        n = nroutes * sizeof (pci_irq_route_t);
        for (i = 0; i < n; i++)
                bufp[i] = 0;
        ((pci_irq_route_hdr_t *)hdrp)->pir_size = n;
        ((pci_irq_route_hdr_t *)hdrp)->pir_addr = (uint32_t)(uintptr_t)bufp;

        bzero(&regs, sizeof (regs));
        regs.eax.word.ax = (PCI_FUNCTION_ID << 8) | PCI_GET_IRQ_ROUTING;

        regs.ds = 0xf000;
        regs.es = FP_SEG((uint_t)(uintptr_t)hdrp);
        regs.edi.word.di = FP_OFF((uint_t)(uintptr_t)hdrp);

        BOP_DOINT(bootops, 0x1a, &regs);

        n = (int)(((pci_irq_route_hdr_t *)hdrp)->pir_size /
            sizeof (pci_irq_route_t));

        if ((regs.eflags & PS_C) != 0) {
                if (nneededp)
                        *nneededp = n;
        } else {
                /*
                 * Copy resulting irq routing data from low memory up to
                 * the kernel address space, avoiding memcpy as usual.
                 */
                if (n <= nroutes) {
                        for (i = 0; i < n * sizeof (pci_irq_route_t); i++)
                                ((uchar_t *)routes)[i] = bufp[i];
                        rval = n;
                }
        }
        return (rval);
}

static void
pci_get_irq_routing_table(void)
{
        pci_irq_route_t *routes;
        int             n = N_PCI_IRQ_ROUTES;
        int             nneeded = 0;
        int             nroutes;

        /*
         * Get irq routing table information.
         * Allocate a buffer for an initial default number of entries.
         * If the bios indicates it needs a larger buffer, try it again.
         * Drive on if it still won't cooperate and play nice after that.
         */
        routes = kmem_zalloc(n * sizeof (pci_irq_route_t), KM_SLEEP);
        nroutes = pci_bios_get_irq_routing(routes, n, &nneeded);
        if (nroutes == 0 && nneeded > n) {
                kmem_free(routes, n * sizeof (pci_irq_route_t));
                if (nneeded > N_PCI_IRQ_ROUTES_MAX) {
                        cmn_err(CE_CONT,
                            "pci: unable to get IRQ routing information, "
                            "required buffer space of %d entries exceeds max\n",
                            nneeded);
                        return;
                }
                n = nneeded;
                routes = kmem_zalloc(n * sizeof (pci_irq_route_t), KM_SLEEP);
                nroutes = pci_bios_get_irq_routing(routes, n, NULL);
                if (nroutes == 0) {
                        cmn_err(CE_CONT,
                            "pci: unable to get IRQ routing information, "
                            "required buffer space for %d entries\n", n);
                }
        }

        if (nroutes > 0) {
                pci_irq_routes = routes;
                pci_irq_nroutes = nroutes;
        } else {
                kmem_free(routes, n * sizeof (pci_irq_route_t));
        }
}

/*
 * Use the results of the PCI BIOS call that returned the routing tables
 * to build the 1275 slot-names property for the indicated bus.
 * Results are returned in buf.  Length is return value, -1 is returned on
 * overflow and zero is returned if no data exists to build a property.
 */
int
pci_slot_names_prop(int bus, char *buf, int len)
{
        uchar_t         dev;
        uchar_t         slot[N_PCI_IRQ_ROUTES_MAX+1];
        uint32_t         mask;
        int             i, nnames, plen;

        ASSERT(pci_irq_nroutes <= N_PCI_IRQ_ROUTES_MAX);

        if (pci_irq_nroutes == 0)
                return (0);
        nnames = 0;
        mask = 0;
        for (i = 0; i < pci_irq_nroutes; i++)
                slot[i] = 0xff;
        for (i = 0; i < pci_irq_nroutes; i++) {
                if (pci_irq_routes[i].pir_bus != bus)
                        continue;
                if (pci_irq_routes[i].pir_slot != 0) {
                        dev = (pci_irq_routes[i].pir_dev & 0xf8) >> 3;
                        slot[dev] = pci_irq_routes[i].pir_slot;
                        mask |= (1 << dev);
                        nnames++;
                }
        }

        if (nnames == 0)
                return (0);

        if (len < (4 + nnames * 8))
                return (-1);
        *(uint32_t *)buf = mask;
        plen = 4;
        for (i = 0; i < pci_irq_nroutes; i++) {
                if (slot[i] == 0xff)
                        continue;
                (void) sprintf(buf + plen, "Slot%d", slot[i]);
                plen += strlen(buf+plen) + 1;
                *(buf + plen) = 0;
        }
        for (; plen % 4; plen++)
                *(buf + plen) = 0;
        return (plen);
}

/*
 * This is used to discover additional PCI buses that may exist in the system in
 * addition to the ACPI _BBN method. Historically these were discovered by
 * asking if there was a valid slot property, e.g. pci_slot_names_prop()
 * returned valid data. In this case we return any entry that has a bus number
 * and a non-zero slot value. We rely on the core PCI code to do dedup for us.
 */
void
pci_bios_bus_iter(pci_prd_root_complex_f cbfunc, void *arg)
{
        int i;
        for (i = 0; i < pci_irq_nroutes; i++) {
                if (pci_irq_routes[i].pir_slot != 0) {
                        if (!cbfunc(pci_irq_routes[i].pir_bus, arg)) {
                                return;
                        }
                }
        }
}