Ok. I didn't make 2.4.0 in 2000. Tough. I tried, but we had some

[davej-history.git] / arch / sparc64 / kernel / pci_common.c

/* $Id: pci_common.c,v 1.12 2000/05/01 06:32:49 davem Exp $
 * pci_common.c: PCI controller common support.
 *
 * Copyright (C) 1999 David S. Miller (davem@redhat.com)
 */

#include <linux/string.h>
#include <linux/malloc.h>
#include <linux/init.h>

#include <asm/pbm.h>

/* Find the OBP PROM device tree node for a PCI device.
 * Return zero if not found.
 */
static int __init find_device_prom_node(struct pci_pbm_info *pbm,
                                        struct pci_dev *pdev,
                                        int bus_prom_node,
                                        struct linux_prom_pci_registers *pregs,
                                        int *nregs)
{
        int node;

        /*
         * Return the PBM's PROM node in case we are it's PCI device,
         * as the PBM's reg property is different to standard PCI reg
         * properties. We would delete this device entry otherwise,
         * which confuses XFree86's device probing...
         */
        if ((pdev->bus->number == pbm->pci_bus->number) && (pdev->devfn == 0) &&
            (pdev->vendor == PCI_VENDOR_ID_SUN) &&
            (pdev->device == PCI_DEVICE_ID_SUN_PBM)) {
                *nregs = 0;
                return bus_prom_node;
        }

        node = prom_getchild(bus_prom_node);
        while (node != 0) {
                int err = prom_getproperty(node, "reg",
                                           (char *)pregs,
                                           sizeof(*pregs) * PROMREG_MAX);
                if (err == 0 || err == -1)
                        goto do_next_sibling;
                if (((pregs[0].phys_hi >> 8) & 0xff) == pdev->devfn) {
                        *nregs = err / sizeof(*pregs);
                        return node;
                }

        do_next_sibling:
                node = prom_getsibling(node);
        }
        return 0;
}

/* Remove a PCI device from the device trees, then
 * free it up.  Note that this must run before
 * the device's resources are registered because we
 * do not handle unregistering them here.
 */
static void pci_device_delete(struct pci_dev *pdev)
{
        list_del(&pdev->global_list);
        list_del(&pdev->bus_list);

        /* Ok, all references are gone, free it up. */
        kfree(pdev);
}

/* Older versions of OBP on PCI systems encode 64-bit MEM
 * space assignments incorrectly, this fixes them up.
 */
static void __init fixup_obp_assignments(struct pcidev_cookie *pcp)
{
        int i;

        for (i = 0; i < pcp->num_prom_assignments; i++) {
                struct linux_prom_pci_registers *ap;
                int space;

                ap = &pcp->prom_assignments[i];
                space = ap->phys_hi >> 24;
                if ((space & 0x3) == 2 &&
                    (space & 0x4) != 0) {
                        ap->phys_hi &= ~(0x7 << 24);
                        ap->phys_hi |= 0x3 << 24;
                }
        }
}

/* Fill in the PCI device cookie sysdata for the given
 * PCI device.  This cookie is the means by which one
 * can get to OBP and PCI controller specific information
 * for a PCI device.
 */
static void __init pdev_cookie_fillin(struct pci_pbm_info *pbm,
                                      struct pci_dev *pdev,
                                      int bus_prom_node)
{
        struct linux_prom_pci_registers pregs[PROMREG_MAX];
        struct pcidev_cookie *pcp;
        int device_prom_node, nregs, err;

        device_prom_node = find_device_prom_node(pbm, pdev, bus_prom_node,
                                                 pregs, &nregs);
        if (device_prom_node == 0) {
                /* If it is not in the OBP device tree then
                 * there must be a damn good reason for it.
                 *
                 * So what we do is delete the device from the
                 * PCI device tree completely.  This scenerio
                 * is seen, for example, on CP1500 for the
                 * second EBUS/HappyMeal pair if the external
                 * connector for it is not present.
                 */
                pci_device_delete(pdev);
                return;
        }

        pcp = kmalloc(sizeof(*pcp), GFP_ATOMIC);
        if (pcp == NULL) {
                prom_printf("PCI_COOKIE: Fatal malloc error, aborting...\n");
                prom_halt();
        }
        pcp->pbm = pbm;
        pcp->prom_node = device_prom_node;
        memcpy(pcp->prom_regs, pregs, sizeof(pcp->prom_regs));
        pcp->num_prom_regs = nregs;
        err = prom_getproperty(device_prom_node, "name",
                               pcp->prom_name, sizeof(pcp->prom_name));
        if (err > 0)
                pcp->prom_name[err] = 0;
        else
                pcp->prom_name[0] = 0;
        if (strcmp(pcp->prom_name, "ebus") == 0) {
                struct linux_prom_ebus_ranges erng[PROM_PCIRNG_MAX];
                int iter;

                /* EBUS is special... */
                err = prom_getproperty(device_prom_node, "ranges",
                                       (char *)&erng[0], sizeof(erng));
                if (err == 0 || err == -1) {
                        prom_printf("EBUS: Fatal error, no range property\n");
                        prom_halt();
                }
                err = (err / sizeof(erng[0]));
                for(iter = 0; iter < err; iter++) {
                        struct linux_prom_ebus_ranges *ep = &erng[iter];
                        struct linux_prom_pci_registers *ap;

                        ap = &pcp->prom_assignments[iter];

                        ap->phys_hi = ep->parent_phys_hi;
                        ap->phys_mid = ep->parent_phys_mid;
                        ap->phys_lo = ep->parent_phys_lo;
                        ap->size_hi = 0;
                        ap->size_lo = ep->size;
                }
                pcp->num_prom_assignments = err;
        } else {
                err = prom_getproperty(device_prom_node,
                                       "assigned-addresses",
                                       (char *)pcp->prom_assignments,
                                       sizeof(pcp->prom_assignments));
                if (err == 0 || err == -1)
                        pcp->num_prom_assignments = 0;
                else
                        pcp->num_prom_assignments =
                                (err / sizeof(pcp->prom_assignments[0]));
        }

        fixup_obp_assignments(pcp);

        pdev->sysdata = pcp;
}

void __init pci_fill_in_pbm_cookies(struct pci_bus *pbus,
                                    struct pci_pbm_info *pbm,
                                    int prom_node)
{
        struct list_head *walk = &pbus->devices;

        /* This loop is coded like this because the cookie
         * fillin routine can delete devices from the tree.
         */
        walk = walk->next;
        while (walk != &pbus->devices) {
                struct pci_dev *pdev = pci_dev_b(walk);
                struct list_head *walk_next = walk->next;

                pdev_cookie_fillin(pbm, pdev, prom_node);

                walk = walk_next;
        }

        walk = &pbus->children;
        walk = walk->next;
        while (walk != &pbus->children) {
                struct pci_bus *this_pbus = pci_bus_b(walk);
                struct pcidev_cookie *pcp = this_pbus->self->sysdata;
                struct list_head *walk_next = walk->next;

                pci_fill_in_pbm_cookies(this_pbus, pbm, pcp->prom_node);

                walk = walk_next;
        }
}

static void __init bad_assignment(struct linux_prom_pci_registers *ap,
                                  struct resource *res,
                                  int do_prom_halt)
{
        prom_printf("PCI: Bogus PROM assignment.\n");
        if (ap)
                prom_printf("PCI: phys[%08x:%08x:%08x] size[%08x:%08x]\n",
                            ap->phys_hi, ap->phys_mid, ap->phys_lo,
                            ap->size_hi, ap->size_lo);
        if (res)
                prom_printf("PCI: RES[%016lx-->%016lx:(%lx)]\n",
                            res->start, res->end, res->flags);
        prom_printf("Please email this information to davem@redhat.com\n");
        if (do_prom_halt)
                prom_halt();
}

static struct resource *
__init get_root_resource(struct linux_prom_pci_registers *ap,
                         struct pci_pbm_info *pbm)
{
        int space = (ap->phys_hi >> 24) & 3;

        switch (space) {
        case 0:
                /* Configuration space, silently ignore it. */
                return NULL;

        case 1:
                /* 16-bit IO space */
                return &pbm->io_space;

        case 2:
                /* 32-bit MEM space */
                return &pbm->mem_space;

        case 3:
                /* 64-bit MEM space, these are allocated out of
                 * the 32-bit mem_space range for the PBM, ie.
                 * we just zero out the upper 32-bits.
                 */
                return &pbm->mem_space;

        default:
                printk("PCI: What is resource space %x? "
                       "Tell davem@redhat.com about it!\n", space);
                return NULL;
        };
}

static struct resource *
__init get_device_resource(struct linux_prom_pci_registers *ap,
                           struct pci_dev *pdev)
{
        struct resource *res;
        int breg = (ap->phys_hi & 0xff);
        int space = (ap->phys_hi >> 24) & 3;

        switch (breg) {
        case  PCI_ROM_ADDRESS:
                /* It had better be MEM space. */
                if (space != 2)
                        bad_assignment(ap, NULL, 0);

                res = &pdev->resource[PCI_ROM_RESOURCE];
                break;

        case PCI_BASE_ADDRESS_0:
        case PCI_BASE_ADDRESS_1:
        case PCI_BASE_ADDRESS_2:
        case PCI_BASE_ADDRESS_3:
        case PCI_BASE_ADDRESS_4:
        case PCI_BASE_ADDRESS_5:
                res = &pdev->resource[(breg - PCI_BASE_ADDRESS_0) / 4];
                break;

        default:
                bad_assignment(ap, NULL, 0);
                res = NULL;
                break;
        };

        return res;
}

static void __init pdev_record_assignments(struct pci_pbm_info *pbm,
                                           struct pci_dev *pdev)
{
        struct pcidev_cookie *pcp = pdev->sysdata;
        int i;

        for (i = 0; i < pcp->num_prom_assignments; i++) {
                struct linux_prom_pci_registers *ap;
                struct resource *root, *res;

                /* The format of this property is specified in
                 * the PCI Bus Binding to IEEE1275-1994.
                 */
                ap = &pcp->prom_assignments[i];
                root = get_root_resource(ap, pbm);
                res = get_device_resource(ap, pdev);
                if (root == NULL || res == NULL)
                        continue;

                /* Ok we know which resource this PROM assignment is
                 * for, sanity check it.
                 */
                if ((res->start & 0xffffffffUL) != ap->phys_lo)
                        bad_assignment(ap, res, 1);

                /* If it is a 64-bit MEM space assignment, verify that
                 * the resource is too and that the upper 32-bits match.
                 */
                if (((ap->phys_hi >> 24) & 3) == 3) {
                        if (((res->flags & IORESOURCE_MEM) == 0) ||
                            ((res->flags & PCI_BASE_ADDRESS_MEM_TYPE_MASK)
                             != PCI_BASE_ADDRESS_MEM_TYPE_64))
                                bad_assignment(ap, res, 1);
                        if ((res->start >> 32) != ap->phys_mid)
                                bad_assignment(ap, res, 1);

                        /* PBM cannot generate cpu initiated PIOs
                         * to the full 64-bit space.  Therefore the
                         * upper 32-bits better be zero.  If it is
                         * not, just skip it and we will assign it
                         * properly ourselves.
                         */
                        if ((res->start >> 32) != 0UL) {
                                printk(KERN_ERR "PCI: OBP assigns out of range MEM address "
                                       "%016lx for region %ld on device %s\n",
                                       res->start, (res - &pdev->resource[0]), pdev->name);
                                continue;
                        }
                }

                /* Adjust the resource into the physical address space
                 * of this PBM.
                 */
                pbm->parent->resource_adjust(pdev, res, root);

                if (request_resource(root, res) < 0) {
                        /* OK, there is some conflict.  But this is fine
                         * since we'll reassign it in the fixup pass.
                         * Nevertheless notify the user that OBP made
                         * an error.
                         */
                        printk(KERN_ERR "PCI: Address space collision on region %ld "
                               "of device %s\n",
                               (res - &pdev->resource[0]), pdev->name);
                }
        }
}

void __init pci_record_assignments(struct pci_pbm_info *pbm,
                                   struct pci_bus *pbus)
{
        struct list_head *walk = &pbus->devices;

        for (walk = walk->next; walk != &pbus->devices; walk = walk->next)
                pdev_record_assignments(pbm, pci_dev_b(walk));

        walk = &pbus->children;
        for (walk = walk->next; walk != &pbus->children; walk = walk->next)
                pci_record_assignments(pbm, pci_bus_b(walk));
}

static void __init pdev_assign_unassigned(struct pci_pbm_info *pbm,
                                          struct pci_dev *pdev)
{
        u32 reg;
        u16 cmd;
        int i, io_seen, mem_seen;

        io_seen = mem_seen = 0;
        for (i = 0; i < PCI_NUM_RESOURCES; i++) {
                struct resource *root, *res;
                unsigned long size, min, max, align;

                res = &pdev->resource[i];

                if (res->flags & IORESOURCE_IO)
                        io_seen++;
                else if (res->flags & IORESOURCE_MEM)
                        mem_seen++;

                /* If it is already assigned or the resource does
                 * not exist, there is nothing to do.
                 */
                if (res->parent != NULL || res->flags == 0UL)
                        continue;

                /* Determine the root we allocate from. */
                if (res->flags & IORESOURCE_IO) {
                        root = &pbm->io_space;
                        min = root->start + 0x400UL;
                        max = root->end;
                } else {
                        root = &pbm->mem_space;
                        min = root->start;
                        max = min + 0x80000000UL;
                }

                size = res->end - res->start;
                align = size + 1;
                if (allocate_resource(root, res, size + 1, min, max, align, NULL, NULL) < 0) {
                        /* uh oh */
                        prom_printf("PCI: Failed to allocate resource %d for %s\n",
                                    i, pdev->name);
                        prom_halt();
                }

                /* Update PCI config space. */
                pbm->parent->base_address_update(pdev, i);
        }

        /* Special case, disable the ROM.  Several devices
         * act funny (ie. do not respond to memory space writes)
         * when it is left enabled.  A good example are Qlogic,ISP
         * adapters.
         */
        pci_read_config_dword(pdev, PCI_ROM_ADDRESS, &reg);
        reg &= ~PCI_ROM_ADDRESS_ENABLE;
        pci_write_config_dword(pdev, PCI_ROM_ADDRESS, reg);

        /* If we saw I/O or MEM resources, enable appropriate
         * bits in PCI command register.
         */
        if (io_seen || mem_seen) {
                pci_read_config_word(pdev, PCI_COMMAND, &cmd);
                if (io_seen)
                        cmd |= PCI_COMMAND_IO;
                if (mem_seen)
                        cmd |= PCI_COMMAND_MEMORY;
                pci_write_config_word(pdev, PCI_COMMAND, cmd);
        }

        /* If this is a PCI bridge or an IDE controller,
         * enable bus mastering.  In the former case also
         * set the cache line size correctly.
         */
        if (((pdev->class >> 8) == PCI_CLASS_BRIDGE_PCI) ||
            (((pdev->class >> 8) == PCI_CLASS_STORAGE_IDE) &&
             ((pdev->class & 0x80) != 0))) {
                pci_read_config_word(pdev, PCI_COMMAND, &cmd);
                cmd |= PCI_COMMAND_MASTER;
                pci_write_config_word(pdev, PCI_COMMAND, cmd);

                if ((pdev->class >> 8) == PCI_CLASS_BRIDGE_PCI)
                        pci_write_config_byte(pdev,
                                              PCI_CACHE_LINE_SIZE,
                                              (64 / sizeof(u32)));
        }
}

void __init pci_assign_unassigned(struct pci_pbm_info *pbm,
                                  struct pci_bus *pbus)
{
        struct list_head *walk = &pbus->devices;

        for (walk = walk->next; walk != &pbus->devices; walk = walk->next)
                pdev_assign_unassigned(pbm, pci_dev_b(walk));

        walk = &pbus->children;
        for (walk = walk->next; walk != &pbus->children; walk = walk->next)
                pci_assign_unassigned(pbm, pci_bus_b(walk));
}

static int __init pci_intmap_match(struct pci_dev *pdev, unsigned int *interrupt)
{
        struct pcidev_cookie *dev_pcp = pdev->sysdata;
        struct pci_pbm_info *pbm = dev_pcp->pbm;
        struct linux_prom_pci_registers *pregs = dev_pcp->prom_regs;
        unsigned int hi, mid, lo, irq;
        int i;

        if (pbm->num_pbm_intmap == 0)
                return 0;

        /* If we are underneath a PCI bridge, use PROM register
         * property of the parent bridge which is closest to
         * the PBM.
         */
        if (pdev->bus->number != pbm->pci_first_busno) {
                struct pcidev_cookie *bus_pcp;
                struct pci_dev *pwalk;
                int offset;

                pwalk = pdev->bus->self;
                while (pwalk->bus &&
                       pwalk->bus->number != pbm->pci_first_busno)
                        pwalk = pwalk->bus->self;

                bus_pcp = pwalk->sysdata;
                pregs = bus_pcp->prom_regs;

                offset = prom_getint(dev_pcp->prom_node,
                                     "fcode-rom-offset");

                /* Did PROM know better and assign an interrupt other
                 * than #INTA to the device? - We test here for presence of
                 * FCODE on the card, in this case we assume PROM has set
                 * correct 'interrupts' property, unless it is quadhme.
                 */
                if (offset == -1 ||
                    !strcmp(dev_pcp->prom_name, "SUNW,qfe") ||
                    !strcmp(dev_pcp->prom_name, "qfe")) {
                        /*
                         * No, use low slot number bits of child as IRQ line.
                         */
                        *interrupt = ((*interrupt - 1 + PCI_SLOT(pdev->devfn)) & 3) + 1;
                }
        }

        hi   = pregs->phys_hi & pbm->pbm_intmask.phys_hi;
        mid  = pregs->phys_mid & pbm->pbm_intmask.phys_mid;
        lo   = pregs->phys_lo & pbm->pbm_intmask.phys_lo;
        irq  = *interrupt & pbm->pbm_intmask.interrupt;

        for (i = 0; i < pbm->num_pbm_intmap; i++) {
                if (pbm->pbm_intmap[i].phys_hi  == hi   &&
                    pbm->pbm_intmap[i].phys_mid == mid  &&
                    pbm->pbm_intmap[i].phys_lo  == lo   &&
                    pbm->pbm_intmap[i].interrupt == irq) {
                        *interrupt = pbm->pbm_intmap[i].cinterrupt;
                        return 1;
                }
        }

        prom_printf("pbm_intmap_match: bus %02x, devfn %02x: ",
                    pdev->bus->number, pdev->devfn);
        prom_printf("IRQ [%08x.%08x.%08x.%08x] not found in interrupt-map\n",
                    pregs->phys_hi, pregs->phys_mid, pregs->phys_lo, *interrupt);
        prom_printf("Please email this information to davem@redhat.com\n");
        prom_halt();
}

static void __init pdev_fixup_irq(struct pci_dev *pdev)
{
        struct pcidev_cookie *pcp = pdev->sysdata;
        struct pci_pbm_info *pbm = pcp->pbm;
        struct pci_controller_info *p = pbm->parent;
        unsigned int portid = p->portid;
        unsigned int prom_irq;
        int prom_node = pcp->prom_node;
        int err;

        err = prom_getproperty(prom_node, "interrupts",
                               (char *)&prom_irq, sizeof(prom_irq));
        if (err == 0 || err == -1) {
                pdev->irq = 0;
                return;
        }

        /* Fully specified already? */
        if (((prom_irq & PCI_IRQ_IGN) >> 6) == portid) {
                pdev->irq = p->irq_build(p, pdev, prom_irq);
                goto have_irq;
        }

        /* An onboard device? (bit 5 set) */
        if ((prom_irq & PCI_IRQ_INO) & 0x20) {
                pdev->irq = p->irq_build(p, pdev, (portid << 6 | prom_irq));
                goto have_irq;
        }

        /* Can we find a matching entry in the interrupt-map? */
        if (pci_intmap_match(pdev, &prom_irq)) {
                pdev->irq = p->irq_build(p, pdev, (portid << 6) | prom_irq);
                goto have_irq;
        }

        /* Ok, we have to do it the hard way. */
        {
                unsigned int bus, slot, line;

                bus = (pbm == &pbm->parent->pbm_B) ? (1 << 4) : 0;

                /* If we have a legal interrupt property, use it as
                 * the IRQ line.
                 */
                if (prom_irq > 0 && prom_irq < 5) {
                        line = ((prom_irq - 1) & 3);
                } else {
                        u8 pci_irq_line;

                        /* Else just directly consult PCI config space. */
                        pci_read_config_byte(pdev, PCI_INTERRUPT_PIN, &pci_irq_line);
                        line = ((pci_irq_line - 1) & 3);
                }

                /* Now figure out the slot. */
                if (pdev->bus->number == pbm->pci_first_busno) {
                        if (pbm == &pbm->parent->pbm_A)
                                slot = (pdev->devfn >> 3) - 1;
                        else
                                slot = (pdev->devfn >> 3) - 2;
                } else {
                        if (pbm == &pbm->parent->pbm_A)
                                slot = (pdev->bus->self->devfn >> 3) - 1;
                        else
                                slot = (pdev->bus->self->devfn >> 3) - 2;
                }
                slot = slot << 2;

                pdev->irq = p->irq_build(p, pdev,
                                         ((portid << 6) & PCI_IRQ_IGN) |
                                         (bus | slot | line));
        }

have_irq:
        pci_write_config_byte(pdev, PCI_INTERRUPT_LINE,
                              pdev->irq & PCI_IRQ_INO);
}

void __init pci_fixup_irq(struct pci_pbm_info *pbm,
                          struct pci_bus *pbus)
{
        struct list_head *walk = &pbus->devices;

        for (walk = walk->next; walk != &pbus->devices; walk = walk->next)
                pdev_fixup_irq(pci_dev_b(walk));

        walk = &pbus->children;
        for (walk = walk->next; walk != &pbus->children; walk = walk->next)
                pci_fixup_irq(pbm, pci_bus_b(walk));
}

#undef DEBUG_BUSMASTERING

static void pdev_setup_busmastering(struct pci_dev *pdev, int is_66mhz)
{
        u16 cmd;
        u8 hdr_type, min_gnt, ltimer;

#ifdef DEBUG_BUSMASTERING
        printk("PCI: Checking DEV(%s), ", pdev->name);
#endif

        pci_read_config_word(pdev, PCI_COMMAND, &cmd);
        cmd |= PCI_COMMAND_MASTER;
        pci_write_config_word(pdev, PCI_COMMAND, cmd);

        /* Read it back, if the mastering bit did not
         * get set, the device does not support bus
         * mastering so we have nothing to do here.
         */
        pci_read_config_word(pdev, PCI_COMMAND, &cmd);
        if ((cmd & PCI_COMMAND_MASTER) == 0) {
#ifdef DEBUG_BUSMASTERING
                printk("no bus mastering...\n");
#endif
                return;
        }

        /* Set correct cache line size, 64-byte on all
         * Sparc64 PCI systems.  Note that the value is
         * measured in 32-bit words.
         */
#ifdef DEBUG_BUSMASTERING
        printk("set cachelinesize, ");
#endif
        pci_write_config_byte(pdev, PCI_CACHE_LINE_SIZE,
                              64 / sizeof(u32));

        pci_read_config_byte(pdev, PCI_HEADER_TYPE, &hdr_type);
        hdr_type &= ~0x80;
        if (hdr_type != PCI_HEADER_TYPE_NORMAL) {
#ifdef DEBUG_BUSMASTERING
                printk("hdr_type=%x, exit\n", hdr_type);
#endif
                return;
        }

        /* If the latency timer is already programmed with a non-zero
         * value, assume whoever set it (OBP or whoever) knows what
         * they are doing.
         */
        pci_read_config_byte(pdev, PCI_LATENCY_TIMER, &ltimer);
        if (ltimer != 0) {
#ifdef DEBUG_BUSMASTERING
                printk("ltimer was %x, exit\n", ltimer);
#endif
                return;
        }

        /* XXX Since I'm tipping off the min grant value to
         * XXX choose a suitable latency timer value, I also
         * XXX considered making use of the max latency value
         * XXX as well.  Unfortunately I've seen too many bogusly
         * XXX low settings for it to the point where it lacks
         * XXX any usefulness.  In one case, an ethernet card
         * XXX claimed a min grant of 10 and a max latency of 5.
         * XXX Now, if I had two such cards on the same bus I
         * XXX could not set the desired burst period (calculated
         * XXX from min grant) without violating the max latency
         * XXX bound.  Duh...
         * XXX
         * XXX I blame dumb PC bios implementors for stuff like
         * XXX this, most of them don't even try to do something
         * XXX sensible with latency timer values and just set some
         * XXX default value (usually 32) into every device.
         */

        pci_read_config_byte(pdev, PCI_MIN_GNT, &min_gnt);

        if (min_gnt == 0) {
                /* If no min_gnt setting then use a default
                 * value.
                 */
                if (is_66mhz)
                        ltimer = 16;
                else
                        ltimer = 32;
        } else {
                int shift_factor;

                if (is_66mhz)
                        shift_factor = 2;
                else
                        shift_factor = 3;

                /* Use a default value when the min_gnt value
                 * is erroneously high.
                 */
                if (((unsigned int) min_gnt << shift_factor) > 512 ||
                    ((min_gnt << shift_factor) & 0xff) == 0) {
                        ltimer = 8 << shift_factor;
                } else {
                        ltimer = min_gnt << shift_factor;
                }
        }

        pci_write_config_byte(pdev, PCI_LATENCY_TIMER, ltimer);
#ifdef DEBUG_BUSMASTERING
        printk("set ltimer to %x\n", ltimer);
#endif
}

void pci_determine_66mhz_disposition(struct pci_pbm_info *pbm,
                                     struct pci_bus *pbus)
{
        struct list_head *walk;
        int all_are_66mhz;
        u16 status;

        if (pbm->is_66mhz_capable == 0) {
                all_are_66mhz = 0;
                goto out;
        }

        walk = &pbus->devices;
        all_are_66mhz = 1;
        for (walk = walk->next; walk != &pbus->devices; walk = walk->next) {
                struct pci_dev *pdev = pci_dev_b(walk);

                pci_read_config_word(pdev, PCI_STATUS, &status);
                if (!(status & PCI_STATUS_66MHZ)) {
                        all_are_66mhz = 0;
                        break;
                }
        }
out:
        pbm->all_devs_66mhz = all_are_66mhz;

        printk("PCI%d(PBM%c): Bus running at %dMHz\n",
               pbm->parent->index,
               (pbm == &pbm->parent->pbm_A) ? 'A' : 'B',
               (all_are_66mhz ? 66 : 33));
}

void pci_setup_busmastering(struct pci_pbm_info *pbm,
                            struct pci_bus *pbus)
{
        struct list_head *walk = &pbus->devices;
        int is_66mhz;

        is_66mhz = pbm->is_66mhz_capable && pbm->all_devs_66mhz;

        for (walk = walk->next; walk != &pbus->devices; walk = walk->next)
                pdev_setup_busmastering(pci_dev_b(walk), is_66mhz);

        walk = &pbus->children;
        for (walk = walk->next; walk != &pbus->children; walk = walk->next)
                pci_setup_busmastering(pbm, pci_bus_b(walk));
}

/* Generic helper routines for PCI error reporting. */
void pci_scan_for_target_abort(struct pci_controller_info *p,
                               struct pci_pbm_info *pbm,
                               struct pci_bus *pbus)
{
        struct list_head *walk = &pbus->devices;

        for (walk = walk->next; walk != &pbus->devices; walk = walk->next) {
                struct pci_dev *pdev = pci_dev_b(walk);
                u16 status, error_bits;

                pci_read_config_word(pdev, PCI_STATUS, &status);
                error_bits =
                        (status & (PCI_STATUS_SIG_TARGET_ABORT |
                                   PCI_STATUS_REC_TARGET_ABORT));
                if (error_bits) {
                        pci_write_config_word(pdev, PCI_STATUS, error_bits);
                        printk("PCI%d(PBM%c): Device [%s] saw Target Abort [%016x]\n",
                               p->index, ((pbm == &p->pbm_A) ? 'A' : 'B'),
                               pdev->name, status);
                }
        }

        walk = &pbus->children;
        for (walk = walk->next; walk != &pbus->children; walk = walk->next)
                pci_scan_for_target_abort(p, pbm, pci_bus_b(walk));
}

void pci_scan_for_master_abort(struct pci_controller_info *p,
                               struct pci_pbm_info *pbm,
                               struct pci_bus *pbus)
{
        struct list_head *walk = &pbus->devices;

        for (walk = walk->next; walk != &pbus->devices; walk = walk->next) {
                struct pci_dev *pdev = pci_dev_b(walk);
                u16 status, error_bits;

                pci_read_config_word(pdev, PCI_STATUS, &status);
                error_bits =
                        (status & (PCI_STATUS_REC_MASTER_ABORT));
                if (error_bits) {
                        pci_write_config_word(pdev, PCI_STATUS, error_bits);
                        printk("PCI%d(PBM%c): Device [%s] received Master Abort [%016x]\n",
                               p->index, ((pbm == &p->pbm_A) ? 'A' : 'B'),
                               pdev->name, status);
                }
        }

        walk = &pbus->children;
        for (walk = walk->next; walk != &pbus->children; walk = walk->next)
                pci_scan_for_master_abort(p, pbm, pci_bus_b(walk));
}

void pci_scan_for_parity_error(struct pci_controller_info *p,
                               struct pci_pbm_info *pbm,
                               struct pci_bus *pbus)
{
        struct list_head *walk = &pbus->devices;

        for (walk = walk->next; walk != &pbus->devices; walk = walk->next) {
                struct pci_dev *pdev = pci_dev_b(walk);
                u16 status, error_bits;

                pci_read_config_word(pdev, PCI_STATUS, &status);
                error_bits =
                        (status & (PCI_STATUS_PARITY |
                                   PCI_STATUS_DETECTED_PARITY));
                if (error_bits) {
                        pci_write_config_word(pdev, PCI_STATUS, error_bits);
                        printk("PCI%d(PBM%c): Device [%s] saw Parity Error [%016x]\n",
                               p->index, ((pbm == &p->pbm_A) ? 'A' : 'B'),
                               pdev->name, status);
                }
        }

        walk = &pbus->children;
        for (walk = walk->next; walk != &pbus->children; walk = walk->next)
                pci_scan_for_parity_error(p, pbm, pci_bus_b(walk));
}