source: trunk/src/devices/device.c

/*
 * This file is part of the coreboot project.
 *
 * It was originally based on the Linux kernel (arch/i386/kernel/pci-pc.c).
 *
 * Modifications are:
 * Copyright (C) 2003 Eric Biederman <ebiederm@xmission.com>
 * Copyright (C) 2003-2004 Linux Networx
 * (Written by Eric Biederman <ebiederman@lnxi.com> for Linux Networx)
 * Copyright (C) 2003 Ronald G. Minnich <rminnich@gmail.com>
 * Copyright (C) 2004-2005 Li-Ta Lo <ollie@lanl.gov>
 * Copyright (C) 2005-2006 Tyan
 * (Written by Yinghai Lu <yhlu@tyan.com> for Tyan)
 * Copyright (C) 2005-2006 Stefan Reinauer <stepan@openbios.org>
 * Copyright (C) 2009 Myles Watson <mylesgw@gmail.com>
 */

/*
 *      (c) 1999--2000 Martin Mares <mj@suse.cz>
 */

/*
 * Lots of mods by Ron Minnich <rminnich@lanl.gov>, with
 * the final architecture guidance from Tom Merritt <tjm@codegen.com>.
 *
 * In particular, we changed from the one-pass original version to
 * Tom's recommended multiple-pass version. I wasn't sure about doing
 * it with multiple passes, until I actually started doing it and saw
 * the wisdom of Tom's recommendations...
 *
 * Lots of cleanups by Eric Biederman to handle bridges, and to
 * handle resource allocation for non-PCI devices.
 */

#include <console/console.h>
#include <bitops.h>
#include <arch/io.h>
#include <device/device.h>
#include <device/pci.h>
#include <device/pci_ids.h>
#include <stdlib.h>
#include <string.h>
#include <smp/spinlock.h>

/** Linked list of ALL devices */
struct device *all_devices = &dev_root;
/** Pointer to the last device */
extern struct device *last_dev;
/** Linked list of free resources */
struct resource *free_resources = NULL;

DECLARE_SPIN_LOCK(dev_lock)

/**
 * Allocate a new device structure.
 *
 * Allocte a new device structure and attach it to the device tree as a
 * child of the parent bus.
 *
 * @param parent Parent bus the newly created device should be attached to.
 * @param path Path to the device to be created.
 * @return Pointer to the newly created device structure.
 *
 * @see device_path
 */
device_t alloc_dev(struct bus *parent, struct device_path *path)
{
        device_t dev, child;

        spin_lock(&dev_lock);

        /* Find the last child of our parent. */
        for (child = parent->children; child && child->sibling; /* */ )
                child = child->sibling;

        dev = malloc(sizeof(*dev));
        if (dev == 0)
                die("alloc_dev(): out of memory.\n");

        memset(dev, 0, sizeof(*dev));
        memcpy(&dev->path, path, sizeof(*path));

        /* By default devices are enabled. */
        dev->enabled = 1;

        /* Add the new device to the list of children of the bus. */
        dev->bus = parent;
        if (child)
                child->sibling = dev;
        else
                parent->children = dev;

        /* Append a new device to the global device list.
         * The list is used to find devices once everything is set up.
         */
        last_dev->next = dev;
        last_dev = dev;

        spin_unlock(&dev_lock);
        return dev;
}

/**
 * Round a number up to an alignment.
 *
 * @param val The starting value.
 * @param roundup Alignment as a power of two.
 * @return Rounded up number.
 */
static resource_t round(resource_t val, unsigned long pow)
{
        resource_t mask;
        mask = (1ULL << pow) - 1ULL;
        val += mask;
        val &= ~mask;
        return val;
}

/**
 * Read the resources on all devices of a given bus.
 *
 * @param bus Bus to read the resources on.
 */
static void read_resources(struct bus *bus)
{
        struct device *curdev;

        printk(BIOS_SPEW, "%s %s bus %x link: %d\n", dev_path(bus->dev),
               __func__, bus->secondary, bus->link_num);

        /* Walk through all devices and find which resources they need. */
        for (curdev = bus->children; curdev; curdev = curdev->sibling) {
                struct bus *link;

                if (!curdev->enabled)
                        continue;

                if (!curdev->ops || !curdev->ops->read_resources) {
                        printk(BIOS_ERR, "%s missing read_resources\n",
                               dev_path(curdev));
                        continue;
                }
                curdev->ops->read_resources(curdev);

                /* Read in the resources behind the current device's links. */
                for (link = curdev->link_list; link; link = link->next)
                        read_resources(link);
        }
        printk(BIOS_SPEW, "%s read_resources bus %d link: %d done\n",
               dev_path(bus->dev), bus->secondary, bus->link_num);
}

struct pick_largest_state {
        struct resource *last;
        struct device *result_dev;
        struct resource *result;
        int seen_last;
};

static void pick_largest_resource(void *gp, struct device *dev,
                                  struct resource *resource)
{
        struct pick_largest_state *state = gp;
        struct resource *last;

        last = state->last;

        /* Be certain to pick the successor to last. */
        if (resource == last) {
                state->seen_last = 1;
                return;
        }
        if (resource->flags & IORESOURCE_FIXED)
                return; /* Skip it. */
        if (last && ((last->align < resource->align) ||
                     ((last->align == resource->align) &&
                      (last->size < resource->size)) ||
                     ((last->align == resource->align) &&
                      (last->size == resource->size) && (!state->seen_last)))) {
                return;
        }
        if (!state->result ||
            (state->result->align < resource->align) ||
            ((state->result->align == resource->align) &&
             (state->result->size < resource->size))) {
                state->result_dev = dev;
                state->result = resource;
        }
}

static struct device *largest_resource(struct bus *bus,
                                       struct resource **result_res,
                                       unsigned long type_mask,
                                       unsigned long type)
{
        struct pick_largest_state state;

        state.last = *result_res;
        state.result_dev = NULL;
        state.result = NULL;
        state.seen_last = 0;

        search_bus_resources(bus, type_mask, type, pick_largest_resource,
                             &state);

        *result_res = state.result;
        return state.result_dev;
}

/**
 * This function is the guts of the resource allocator.
 *
 * The problem.
 *  - Allocate resource locations for every device.
 *  - Don't overlap, and follow the rules of bridges.
 *  - Don't overlap with resources in fixed locations.
 *  - Be efficient so we don't have ugly strategies.
 *
 * The strategy.
 * - Devices that have fixed addresses are the minority so don't
 *   worry about them too much. Instead only use part of the address
 *   space for devices with programmable addresses. This easily handles
 *   everything except bridges.
 *
 * - PCI devices are required to have their sizes and their alignments
 *   equal. In this case an optimal solution to the packing problem
 *   exists. Allocate all devices from highest alignment to least
 *   alignment or vice versa. Use this.
 *
 * - So we can handle more than PCI run two allocation passes on bridges. The
 *   first to see how large the resources are behind the bridge, and what
 *   their alignment requirements are. The second to assign a safe address to
 *   the devices behind the bridge. This allows us to treat a bridge as just
 *   a device with a couple of resources, and not need to special case it in
 *   the allocator. Also this allows handling of other types of bridges.
 *
 * @param bus The bus we are traversing.
 * @param bridge The bridge resource which must contain the bus' resources.
 * @param type_mask This value gets ANDed with the resource type.
 * @param type This value must match the result of the AND.
 * @return TODO
 */
static void compute_resources(struct bus *bus, struct resource *bridge,
                              unsigned long type_mask, unsigned long type)
{
        struct device *dev;
        struct resource *resource;
        resource_t base;
        base = round(bridge->base, bridge->align);

        printk(BIOS_SPEW,  "%s %s_%s: base: %llx size: %llx align: %d gran: %d"
               " limit: %llx\n", dev_path(bus->dev), __func__,
               (type & IORESOURCE_IO) ? "io" : (type & IORESOURCE_PREFETCH) ?
               "prefmem" : "mem", base, bridge->size, bridge->align,
               bridge->gran, bridge->limit);

        /* For each child which is a bridge, compute the resource needs. */
        for (dev = bus->children; dev; dev = dev->sibling) {
                struct resource *child_bridge;

                if (!dev->link_list)
                        continue;

                /* Find the resources with matching type flags. */
                for (child_bridge = dev->resource_list; child_bridge;
                     child_bridge = child_bridge->next) {
                        struct bus* link;

                        if (!(child_bridge->flags & IORESOURCE_BRIDGE)
                            || (child_bridge->flags & type_mask) != type)
                                continue;

                        /*
                         * Split prefetchable memory if combined. Many domains
                         * use the same address space for prefetchable memory
                         * and non-prefetchable memory. Bridges below them need
                         * it separated. Add the PREFETCH flag to the type_mask
                         * and type.
                         */
                        link = dev->link_list;
                        while (link && link->link_num !=
                                        IOINDEX_LINK(child_bridge->index))
                                link = link->next;

                        if (link == NULL) {
                                printk(BIOS_ERR, "link %ld not found on %s\n",
                                       IOINDEX_LINK(child_bridge->index),
                                       dev_path(dev));
                        }

                        compute_resources(link, child_bridge,
                                          type_mask | IORESOURCE_PREFETCH,
                                          type | (child_bridge->flags &
                                                  IORESOURCE_PREFETCH));
                }
        }

        /* Remember we haven't found anything yet. */
        resource = NULL;

        /*
         * Walk through all the resources on the current bus and compute the
         * amount of address space taken by them. Take granularity and
         * alignment into account.
         */
        while ((dev = largest_resource(bus, &resource, type_mask, type))) {

                /* Size 0 resources can be skipped. */
                if (!resource->size)
                        continue;

                /* Propagate the resource alignment to the bridge resource. */
                if (resource->align > bridge->align)
                        bridge->align = resource->align;

                /* Propagate the resource limit to the bridge register. */
                if (bridge->limit > resource->limit)
                        bridge->limit = resource->limit;

                /* Warn if it looks like APICs aren't declared. */
                if ((resource->limit == 0xffffffff) &&
                    (resource->flags & IORESOURCE_ASSIGNED)) {
                        printk(BIOS_ERR,
                               "Resource limit looks wrong! (no APIC?)\n");
                        printk(BIOS_ERR, "%s %02lx limit %08Lx\n",
                               dev_path(dev), resource->index, resource->limit);
                }

                if (resource->flags & IORESOURCE_IO) {
                        /*
                         * Don't allow potential aliases over the legacy PCI
                         * expansion card addresses. The legacy PCI decodes
                         * only 10 bits, uses 0x100 - 0x3ff. Therefore, only
                         * 0x00 - 0xff can be used out of each 0x400 block of
                         * I/O space.
                         */
                        if ((base & 0x300) != 0) {
                                base = (base & ~0x3ff) + 0x400;
                        }
                        /*
                         * Don't allow allocations in the VGA I/O range.
                         * PCI has special cases for that.
                         */
                        else if ((base >= 0x3b0) && (base <= 0x3df)) {
                                base = 0x3e0;
                        }
                }
                /* Base must be aligned. */
                base = round(base, resource->align);
                resource->base = base;
                base += resource->size;

                printk(BIOS_SPEW, "%s %02lx *  [0x%llx - 0x%llx] %s\n",
                       dev_path(dev), resource->index, resource->base,
                       resource->base + resource->size - 1,
                       (resource->flags & IORESOURCE_IO) ? "io" :
                       (resource->flags & IORESOURCE_PREFETCH) ?
                        "prefmem" : "mem");
        }

        /*
         * A PCI bridge resource does not need to be a power of two size, but
         * it does have a minimum granularity. Round the size up to that
         * minimum granularity so we know not to place something else at an
         * address postitively decoded by the bridge.
         */
        bridge->size = round(base, bridge->gran) -
                       round(bridge->base, bridge->align);

        printk(BIOS_SPEW, "%s %s_%s: base: %llx size: %llx align: %d gran: %d"
               " limit: %llx done\n", dev_path(bus->dev), __func__,
               (bridge->flags & IORESOURCE_IO) ? "io" :
               (bridge->flags & IORESOURCE_PREFETCH) ? "prefmem" : "mem",
               base, bridge->size, bridge->align, bridge->gran, bridge->limit);
}

/**
 * This function is the second part of the resource allocator.
 *
 * See the compute_resources function for a more detailed explanation.
 *
 * This function assigns the resources a value.
 *
 * @param bus The bus we are traversing.
 * @param bridge The bridge resource which must contain the bus' resources.
 * @param type_mask This value gets ANDed with the resource type.
 * @param type This value must match the result of the AND.
 *
 * @see compute_resources
 */
static void allocate_resources(struct bus *bus, struct resource *bridge,
                               unsigned long type_mask, unsigned long type)
{
        struct device *dev;
        struct resource *resource;
        resource_t base;
        base = bridge->base;

        printk(BIOS_SPEW, "%s %s_%s: base:%llx size:%llx align:%d gran:%d "
               "limit:%llx\n", dev_path(bus->dev), __func__,
               (type & IORESOURCE_IO) ? "io" : (type & IORESOURCE_PREFETCH) ?
               "prefmem" : "mem",
               base, bridge->size, bridge->align, bridge->gran, bridge->limit);

        /* Remember we haven't found anything yet. */
        resource = NULL;

        /*
         * Walk through all the resources on the current bus and allocate them
         * address space.
         */
        while ((dev = largest_resource(bus, &resource, type_mask, type))) {

                /* Propagate the bridge limit to the resource register. */
                if (resource->limit > bridge->limit)
                        resource->limit = bridge->limit;

                /* Size 0 resources can be skipped. */
                if (!resource->size) {
                        /* Set the base to limit so it doesn't confuse tolm. */
                        resource->base = resource->limit;
                        resource->flags |= IORESOURCE_ASSIGNED;
                        continue;
                }

                if (resource->flags & IORESOURCE_IO) {
                        /*
                         * Don't allow potential aliases over the legacy PCI
                         * expansion card addresses. The legacy PCI decodes
                         * only 10 bits, uses 0x100 - 0x3ff. Therefore, only
                         * 0x00 - 0xff can be used out of each 0x400 block of
                         * I/O space.
                         */
                        if ((base & 0x300) != 0) {
                                base = (base & ~0x3ff) + 0x400;
                        }
                        /*
                         * Don't allow allocations in the VGA I/O range.
                         * PCI has special cases for that.
                         */
                        else if ((base >= 0x3b0) && (base <= 0x3df)) {
                                base = 0x3e0;
                        }
                }

                if ((round(base, resource->align) + resource->size - 1) <=
                    resource->limit) {
                        /* Base must be aligned. */
                        base = round(base, resource->align);
                        resource->base = base;
                        resource->flags |= IORESOURCE_ASSIGNED;
                        resource->flags &= ~IORESOURCE_STORED;
                        base += resource->size;
                } else {
                        printk(BIOS_ERR, "!! Resource didn't fit !!\n");
                        printk(BIOS_ERR, "   aligned base %llx size %llx "
                               "limit %llx\n", round(base, resource->align),
                               resource->size, resource->limit);
                        printk(BIOS_ERR, "   %llx needs to be <= %llx "
                               "(limit)\n", (round(base, resource->align) +
                                resource->size) - 1, resource->limit);
                        printk(BIOS_ERR, "   %s%s %02lx *  [0x%llx - 0x%llx]"
                               " %s\n", (resource->flags & IORESOURCE_ASSIGNED)
                               ? "Assigned: " : "", dev_path(dev),
                               resource->index, resource->base,
                               resource->base + resource->size - 1,
                               (resource->flags & IORESOURCE_IO) ? "io"
                               : (resource->flags & IORESOURCE_PREFETCH)
                               ? "prefmem" : "mem");
                }

                printk(BIOS_SPEW, "%s%s %02lx *  [0x%llx - 0x%llx] %s\n",
                       (resource->flags & IORESOURCE_ASSIGNED) ? "Assigned: "
                       : "", dev_path(dev), resource->index, resource->base,
                       resource->size ? resource->base + resource->size - 1 :
                       resource->base, (resource->flags & IORESOURCE_IO)
                       ? "io" : (resource->flags & IORESOURCE_PREFETCH)
                       ? "prefmem" : "mem");
        }

        /*
         * A PCI bridge resource does not need to be a power of two size, but
         * it does have a minimum granularity. Round the size up to that
         * minimum granularity so we know not to place something else at an
         * address positively decoded by the bridge.
         */

        bridge->flags |= IORESOURCE_ASSIGNED;

        printk(BIOS_SPEW, "%s %s_%s: next_base: %llx size: %llx align: %d "
               "gran: %d done\n", dev_path(bus->dev), __func__,
               (type & IORESOURCE_IO) ? "io" : (type & IORESOURCE_PREFETCH) ?
               "prefmem" : "mem", base, bridge->size, bridge->align,
               bridge->gran);

        /* For each child which is a bridge, allocate_resources. */
        for (dev = bus->children; dev; dev = dev->sibling) {
                struct resource *child_bridge;

                if (!dev->link_list)
                        continue;

                /* Find the resources with matching type flags. */
                for (child_bridge = dev->resource_list; child_bridge;
                     child_bridge = child_bridge->next) {
                        struct bus* link;

                        if (!(child_bridge->flags & IORESOURCE_BRIDGE) ||
                            (child_bridge->flags & type_mask) != type)
                                continue;

                        /*
                         * Split prefetchable memory if combined. Many domains
                         * use the same address space for prefetchable memory
                         * and non-prefetchable memory. Bridges below them need
                         * it separated. Add the PREFETCH flag to the type_mask
                         * and type.
                         */
                        link = dev->link_list;
                        while (link && link->link_num !=
                                       IOINDEX_LINK(child_bridge->index))
                                link = link->next;
                        if (link == NULL)
                                printk(BIOS_ERR, "link %ld not found on %s\n",
                                       IOINDEX_LINK(child_bridge->index),
                                       dev_path(dev));

                        allocate_resources(link, child_bridge,
                                           type_mask | IORESOURCE_PREFETCH,
                                           type | (child_bridge->flags &
                                                   IORESOURCE_PREFETCH));
                }
        }
}

#if CONFIG_PCI_64BIT_PREF_MEM == 1
#define MEM_MASK (IORESOURCE_PREFETCH | IORESOURCE_MEM)
#else
#define MEM_MASK (IORESOURCE_MEM)
#endif

#define IO_MASK   (IORESOURCE_IO)
#define PREF_TYPE (IORESOURCE_PREFETCH | IORESOURCE_MEM)
#define MEM_TYPE  (IORESOURCE_MEM)
#define IO_TYPE   (IORESOURCE_IO)

struct constraints {
        struct resource pref, io, mem;
};

static void constrain_resources(struct device *dev, struct constraints* limits)
{
        struct device *child;
        struct resource *res;
        struct resource *lim;
        struct bus *link;

        printk(BIOS_SPEW, "%s: %s\n", __func__, dev_path(dev));

        /* Constrain limits based on the fixed resources of this device. */
        for (res = dev->resource_list; res; res = res->next) {
                if (!(res->flags & IORESOURCE_FIXED))
                        continue;
                if (!res->size) {
                        /* It makes no sense to have 0-sized, fixed resources.*/
                        printk(BIOS_ERR, "skipping %s@%lx fixed resource, "
                               "size=0!\n", dev_path(dev), res->index);
                        continue;
                }

                /* PREFETCH, MEM, or I/O - skip any others. */
                if ((res->flags & MEM_MASK) == PREF_TYPE)
                        lim = &limits->pref;
                else if ((res->flags & MEM_MASK) == MEM_TYPE)
                        lim = &limits->mem;
                else if ((res->flags & IO_MASK) == IO_TYPE)
                        lim = &limits->io;
                else
                        continue;

                /*
                 * Is it a fixed resource outside the current known region?
                 * If so, we don't have to consider it - it will be handled
                 * correctly and doesn't affect current region's limits.
                 */
                if (((res->base + res->size -1) < lim->base)
                    || (res->base > lim->limit))
                        continue;

                /*
                 * Choose to be above or below fixed resources. This check is
                 * signed so that "negative" amounts of space are handled
                 * correctly.
                 */
                if ((signed long long)(lim->limit - (res->base + res->size -1))
                    > (signed long long)(res->base - lim->base))
                        lim->base = res->base + res->size;
                else
                        lim->limit = res->base -1;
        }

        /* Descend into every enabled child and look for fixed resources. */
        for (link = dev->link_list; link; link = link->next) {
                for (child = link->children; child; child = child->sibling) {
                        if (child->enabled)
                                constrain_resources(child, limits);
                }
        }
}

static void avoid_fixed_resources(struct device *dev)
{
        struct constraints limits;
        struct resource *res;

        printk(BIOS_SPEW, "%s: %s\n", __func__, dev_path(dev));

        /* Initialize constraints to maximum size. */
        limits.pref.base = 0;
        limits.pref.limit = 0xffffffffffffffffULL;
        limits.io.base = 0;
        limits.io.limit = 0xffffffffffffffffULL;
        limits.mem.base = 0;
        limits.mem.limit = 0xffffffffffffffffULL;

        /* Constrain the limits to dev's initial resources. */
        for (res = dev->resource_list; res; res = res->next) {
                if ((res->flags & IORESOURCE_FIXED))
                        continue;
                printk(BIOS_SPEW, "%s:@%s %02lx limit %08Lx\n", __func__,
                       dev_path(dev), res->index, res->limit);
                if ((res->flags & MEM_MASK) == PREF_TYPE &&
                    (res->limit < limits.pref.limit))
                        limits.pref.limit = res->limit;
                if ((res->flags & MEM_MASK) == MEM_TYPE &&
                    (res->limit < limits.mem.limit))
                        limits.mem.limit = res->limit;
                if ((res->flags & IO_MASK) == IO_TYPE &&
                    (res->limit < limits.io.limit))
                        limits.io.limit = res->limit;
        }

        /* Look through the tree for fixed resources and update the limits. */
        constrain_resources(dev, &limits);

        /* Update dev's resources with new limits. */
        for (res = dev->resource_list; res; res = res->next) {
                struct resource *lim;

                if ((res->flags & IORESOURCE_FIXED))
                        continue;

                /* PREFETCH, MEM, or I/O - skip any others. */
                if ((res->flags & MEM_MASK) == PREF_TYPE)
                        lim = &limits.pref;
                else if ((res->flags & MEM_MASK) == MEM_TYPE)
                        lim = &limits.mem;
                else if ((res->flags & IO_MASK) == IO_TYPE)
                        lim = &limits.io;
                else
                        continue;

                printk(BIOS_SPEW, "%s2: %s@%02lx limit %08Lx\n", __func__,
                             dev_path(dev), res->index, res->limit);
                printk(BIOS_SPEW, "\tlim->base %08Lx lim->limit %08Lx\n",
                             lim->base, lim->limit);

                /* Is the resource outside the limits? */
                if (lim->base > res->base)
                        res->base = lim->base;
                if (res->limit > lim->limit)
                        res->limit = lim->limit;
        }
}

#if CONFIG_VGA_BRIDGE_SETUP == 1
device_t vga_pri = 0;
static void set_vga_bridge_bits(void)
{
        /*
         * FIXME: Modify set_vga_bridge() so it is less PCI centric!
         * This function knows too much about PCI stuff, it should be just
         * an iterator/visitor.
         */

        /* FIXME: Handle the VGA palette snooping. */
        struct device *dev, *vga, *vga_onboard, *vga_first, *vga_last;
        struct bus *bus;

        bus = 0;
        vga = 0;
        vga_onboard = 0;
        vga_first = 0;
        vga_last = 0;

        for (dev = all_devices; dev; dev = dev->next) {

                if (!dev->enabled)
                        continue;

                if (((dev->class >> 16) == PCI_BASE_CLASS_DISPLAY) &&
                    ((dev->class >> 8) != PCI_CLASS_DISPLAY_OTHER)) {
                        if (!vga_first) {
                                if (dev->on_mainboard)
                                        vga_onboard = dev;
                                else
                                        vga_first = dev;
                        } else {
                                if (dev->on_mainboard)
                                        vga_onboard = dev;
                                else
                                        vga_last = dev;
                        }

                        /* It isn't safe to enable other VGA cards. */
                        dev->command &= ~(PCI_COMMAND_MEMORY | PCI_COMMAND_IO);
                }
        }

        vga = vga_last;

        if (!vga)
                vga = vga_first;

#if CONFIG_ONBOARD_VGA_IS_PRIMARY == 1
        if (vga_onboard)        /* Will use onboard VGA as primary. */
#else
        if (!vga)               /* Will use last add-on adapter as primary. */
#endif
        {
                vga = vga_onboard;
        }

        if (vga) {
                /* VGA is first add-on card or the only onboard VGA. */
                printk(BIOS_DEBUG, "Setting up VGA for %s\n", dev_path(vga));
                /* All legacy VGA cards have MEM & I/O space registers. */
                vga->command |= (PCI_COMMAND_MEMORY | PCI_COMMAND_IO);
                vga_pri = vga;
                bus = vga->bus;
        }

        /* Now walk up the bridges setting the VGA enable. */
        while (bus) {
                printk(BIOS_DEBUG, "Setting PCI_BRIDGE_CTL_VGA for bridge %s\n",
                       dev_path(bus->dev));
                bus->bridge_ctrl |= PCI_BRIDGE_CTL_VGA;
                bus = (bus == bus->dev->bus) ? 0 : bus->dev->bus;
        }
}

#endif

/**
 * Assign the computed resources to the devices on the bus.
 *
 * Use the device specific set_resources() method to store the computed
 * resources to hardware. For bridge devices, the set_resources() method
 * has to recurse into every down stream buses.
 *
 * Mutual recursion:
 *      assign_resources() -> device_operation::set_resources()
 *      device_operation::set_resources() -> assign_resources()
 *
 * @param bus Pointer to the structure for this bus.
 */
void assign_resources(struct bus *bus)
{
        struct device *curdev;

        printk(BIOS_SPEW, "%s assign_resources, bus %d link: %d\n",
               dev_path(bus->dev), bus->secondary, bus->link_num);

        for (curdev = bus->children; curdev; curdev = curdev->sibling) {
                if (!curdev->enabled || !curdev->resource_list)
                        continue;

                if (!curdev->ops || !curdev->ops->set_resources) {
                        printk(BIOS_ERR, "%s missing set_resources\n",
                               dev_path(curdev));
                        continue;
                }
                curdev->ops->set_resources(curdev);
        }
        printk(BIOS_SPEW, "%s assign_resources, bus %d link: %d\n",
               dev_path(bus->dev), bus->secondary, bus->link_num);
}

/**
 * Enable the resources for devices on a link.
 *
 * Enable resources of the device by calling the device specific
 * enable_resources() method.
 *
 * The parent's resources should be enabled first to avoid having enabling
 * order problem. This is done by calling the parent's enable_resources()
 * method before its childrens' enable_resources() methods.
 *
 * @param link The link whose devices' resources are to be enabled.
 */
static void enable_resources(struct bus *link)
{
        struct device *dev;
        struct bus *c_link;

        for (dev = link->children; dev; dev = dev->sibling) {
                if (dev->enabled && dev->ops && dev->ops->enable_resources)
                        dev->ops->enable_resources(dev);
        }

        for (dev = link->children; dev; dev = dev->sibling) {
                for (c_link = dev->link_list; c_link; c_link = c_link->next)
                        enable_resources(c_link);
        }
}

/**
 * Reset all of the devices on a bus and clear the bus's reset_needed flag.
 *
 * @param bus Pointer to the bus structure.
 * @return 1 if the bus was successfully reset, 0 otherwise.
 */
int reset_bus(struct bus *bus)
{
        if (bus && bus->dev && bus->dev->ops && bus->dev->ops->reset_bus) {
                bus->dev->ops->reset_bus(bus);
                bus->reset_needed = 0;
                return 1;
        }
        return 0;
}

/**
 * Scan for devices on a bus.
 *
 * If there are bridges on the bus, recursively scan the buses behind the
 * bridges. If the setting up and tuning of the bus causes a reset to be
 * required, reset the bus and scan it again.
 *
 * @param busdev Pointer to the bus device.
 * @param max Current bus number.
 * @return The maximum bus number found, after scanning all subordinate buses.
 */
unsigned int scan_bus(struct device *busdev, unsigned int max)
{
        unsigned int new_max;
        int do_scan_bus;

        if (!busdev || !busdev->enabled || !busdev->ops ||
            !busdev->ops->scan_bus) {
                return max;
        }

        do_scan_bus = 1;
        while (do_scan_bus) {
                struct bus *link;
                new_max = busdev->ops->scan_bus(busdev, max);
                do_scan_bus = 0;
                for (link = busdev->link_list; link; link = link->next) {
                        if (link->reset_needed) {
                                if (reset_bus(link))
                                        do_scan_bus = 1;
                                else
                                        busdev->bus->reset_needed = 1;
                        }
                }
        }
        return new_max;
}

/**
 * Determine the existence of devices and extend the device tree.
 *
 * Most of the devices in the system are listed in the mainboard devicetree.cb
 * file. The device structures for these devices are generated at compile
 * time by the config tool and are organized into the device tree. This
 * function determines if the devices created at compile time actually exist
 * in the physical system.
 *
 * For devices in the physical system but not listed in devicetree.cb,
 * the device structures have to be created at run time and attached to the
 * device tree.
 *
 * This function starts from the root device 'dev_root', scans the buses in
 * the system recursively, and modifies the device tree according to the
 * result of the probe.
 *
 * This function has no idea how to scan and probe buses and devices at all.
 * It depends on the bus/device specific scan_bus() method to do it. The
 * scan_bus() method also has to create the device structure and attach
 * it to the device tree.
 */
void dev_enumerate(void)
{
        struct device *root;

        printk(BIOS_INFO, "Enumerating buses...\n");

        root = &dev_root;

        show_all_devs(BIOS_SPEW, "Before device enumeration.");
        printk(BIOS_SPEW, "Compare with tree...\n");
        show_devs_tree(root, BIOS_SPEW, 0, 0);

        if (root->chip_ops && root->chip_ops->enable_dev)
                root->chip_ops->enable_dev(root);

        if (!root->ops || !root->ops->scan_bus) {
                printk(BIOS_ERR, "dev_root missing scan_bus operation");
                return;
        }
        scan_bus(root, 0);
        printk(BIOS_INFO, "done\n");
}

/**
 * Configure devices on the devices tree.
 *
 * Starting at the root of the device tree, travel it recursively in two
 * passes. In the first pass, we compute and allocate resources (ranges)
 * requried by each device. In the second pass, the resources ranges are
 * relocated to their final position and stored to the hardware.
 *
 * I/O resources grow upward. MEM resources grow downward.
 *
 * Since the assignment is hierarchical we set the values into the dev_root
 * struct.
 */
void dev_configure(void)
{
        struct resource *res;
        struct device *root;
        struct device *child;

#if CONFIG_VGA_BRIDGE_SETUP == 1
        set_vga_bridge_bits();
#endif

        printk(BIOS_INFO, "Allocating resources...\n");

        root = &dev_root;

        /*
         * Each domain should create resources which contain the entire address
         * space for IO, MEM, and PREFMEM resources in the domain. The
         * allocation of device resources will be done from this address space.
         */

        /* Read the resources for the entire tree. */

        printk(BIOS_INFO, "Reading resources...\n");
        read_resources(root->link_list);
        printk(BIOS_INFO, "Done reading resources.\n");

        print_resource_tree(root, BIOS_SPEW, "After reading.");

        /* Compute resources for all domains. */
        for (child = root->link_list->children; child; child = child->sibling) {
                if (!(child->path.type == DEVICE_PATH_PCI_DOMAIN))
                        continue;
                for (res = child->resource_list; res; res = res->next) {
                        if (res->flags & IORESOURCE_FIXED)
                                continue;
                        if (res->flags & IORESOURCE_PREFETCH) {
                                compute_resources(child->link_list,
                                                  res, MEM_MASK, PREF_TYPE);
                                continue;
                        }
                        if (res->flags & IORESOURCE_MEM) {
                                compute_resources(child->link_list,
                                                  res, MEM_MASK, MEM_TYPE);
                                continue;
                        }
                        if (res->flags & IORESOURCE_IO) {
                                compute_resources(child->link_list,
                                                  res, IO_MASK, IO_TYPE);
                                continue;
                        }
                }
        }

        /* For all domains. */
        for (child = root->link_list->children; child; child=child->sibling)
                if (child->path.type == DEVICE_PATH_PCI_DOMAIN)
                        avoid_fixed_resources(child);

        /*
         * Now we need to adjust the resources. MEM resources need to start at
         * the highest address managable.
         */
        for (child = root->link_list->children; child; child = child->sibling) {
                if (child->path.type != DEVICE_PATH_PCI_DOMAIN)
                        continue;
                for (res = child->resource_list; res; res = res->next) {
                        if (!(res->flags & IORESOURCE_MEM) ||
                            res->flags & IORESOURCE_FIXED)
                                continue;
                        res->base = resource_max(res);
                }
        }

        /* Store the computed resource allocations into device registers ... */
        printk(BIOS_INFO, "Setting resources...\n");
        for (child = root->link_list->children; child; child = child->sibling) {
                if (!(child->path.type == DEVICE_PATH_PCI_DOMAIN))
                        continue;
                for (res = child->resource_list; res; res = res->next) {
                        if (res->flags & IORESOURCE_FIXED)
                                continue;
                        if (res->flags & IORESOURCE_PREFETCH) {
                                allocate_resources(child->link_list,
                                                   res, MEM_MASK, PREF_TYPE);
                                continue;
                        }
                        if (res->flags & IORESOURCE_MEM) {
                                allocate_resources(child->link_list,
                                                   res, MEM_MASK, MEM_TYPE);
                                continue;
                        }
                        if (res->flags & IORESOURCE_IO) {
                                allocate_resources(child->link_list,
                                                   res, IO_MASK, IO_TYPE);
                                continue;
                        }
                }
        }
        assign_resources(root->link_list);
        printk(BIOS_INFO, "Done setting resources.\n");
        print_resource_tree(root, BIOS_SPEW, "After assigning values.");

        printk(BIOS_INFO, "Done allocating resources.\n");
}

/**
 * Enable devices on the device tree.
 *
 * Starting at the root, walk the tree and enable all devices/bridges by
 * calling the device's enable_resources() method.
 */
void dev_enable(void)
{
        struct bus *link;

        printk(BIOS_INFO, "Enabling resources...\n");

        /* Now enable everything. */
        for (link = dev_root.link_list; link; link = link->next)
                enable_resources(link);

        printk(BIOS_INFO, "done.\n");
}

/**
 * Initialize a specific device.
 *
 * The parent should be initialized first to avoid having an ordering problem.
 * This is done by calling the parent's init() method before its childrens'
 * init() methods.
 *
 * @param dev The device to be initialized.
 */
static void init_dev(struct device *dev)
{
        if (!dev->enabled)
                return;

        if (!dev->initialized && dev->ops && dev->ops->init) {
                if (dev->path.type == DEVICE_PATH_I2C) {
                        printk(BIOS_DEBUG, "smbus: %s[%d]->",
                               dev_path(dev->bus->dev), dev->bus->link_num);
                }

                printk(BIOS_DEBUG, "%s init\n", dev_path(dev));
                dev->initialized = 1;
                dev->ops->init(dev);
        }
}

static void init_link(struct bus *link)
{
        struct device *dev;
        struct bus *c_link;

        for (dev = link->children; dev; dev = dev->sibling)
                init_dev(dev);

        for (dev = link->children; dev; dev = dev->sibling) {
                for (c_link = dev->link_list; c_link; c_link = c_link->next)
                        init_link(c_link);
        }
}

/**
 * Initialize all devices in the global device tree.
 *
 * Starting at the root device, call the device's init() method to do
 * device-specific setup, then call each child's init() method.
 */
void dev_initialize(void)
{
        struct bus *link;

        printk(BIOS_INFO, "Initializing devices...\n");

        /* First call the mainboard init. */
        init_dev(&dev_root);

        /* Now initialize everything. */
        for (link = dev_root.link_list; link; link = link->next)
                init_link(link);

        printk(BIOS_INFO, "Devices initialized\n");
        show_all_devs(BIOS_SPEW, "After init.");
}