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/*
 *      drivers/pci/setup-bus.c
 *
 * Extruded from code written by
 *      Dave Rusling (david.rusling@reo.mts.dec.com)
 *      David Mosberger (davidm@cs.arizona.edu)
 *      David Miller (davem@redhat.com)
 *
 * Support routines for initializing a PCI subsystem.
 */

/*
 * Nov 2000, Ivan Kokshaysky <ink@jurassic.park.msu.ru>
 *           PCI-PCI bridges cleanup, sorted resource allocation.
 * Feb 2002, Ivan Kokshaysky <ink@jurassic.park.msu.ru>
 *           Converted to allocation in 3 passes, which gives
 *           tighter packing. Prefetchable range support.
 */

#include <linuxcomp.h>

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/cache.h>
#include <linux/slab.h>


#define DEBUG_CONFIG 1
#if DEBUG_CONFIG
# define DBGC(args)     printk args
#else
# define DBGC(args)
#endif

#define ROUND_UP(x, a)          (((x) + (a) - 1) & ~((a) - 1))

/*
 * FIXME: IO should be max 256 bytes.  However, since we may
 * have a P2P bridge below a cardbus bridge, we need 4K.
 */
#define CARDBUS_IO_SIZE         (4096)
#define CARDBUS_MEM_SIZE        (32*1024*1024)

static int __devinit
pbus_assign_resources_sorted(struct pci_bus *bus)
{
        struct pci_dev *dev;
        struct resource *res;
        struct resource_list head, *list, *tmp;
        int idx, found_vga = 0;

        head.next = NULL;
        list_for_each_entry(dev, &bus->devices, bus_list) {
                u16 class = dev->class >> 8;

                if (class == PCI_CLASS_DISPLAY_VGA
                                || class == PCI_CLASS_NOT_DEFINED_VGA)
                        found_vga = 1;

                pdev_sort_resources(dev, &head);
        }

        for (list = head.next; list;) {
                res = list->res;
                idx = res - &list->dev->resource[0];
                pci_assign_resource(list->dev, idx);
                tmp = list;
                list = list->next;
                kfree(tmp);
        }

        return found_vga;
}

static void __devinit
pci_setup_cardbus(struct pci_bus *bus)
{
        struct pci_dev *bridge = bus->self;
        struct pci_bus_region region;

        printk("PCI: Bus %d, cardbus bridge: %s\n",
                bus->number, pci_name(bridge));

        pcibios_resource_to_bus(bridge, &region, bus->resource[0]);
        if (bus->resource[0]->flags & IORESOURCE_IO) {
                /*
                 * The IO resource is allocated a range twice as large as it
                 * would normally need.  This allows us to set both IO regs.
                 */
                printk("  IO window: %08lx-%08lx\n",
                        region.start, region.end);
                pci_write_config_dword(bridge, PCI_CB_IO_BASE_0,
                                        region.start);
                pci_write_config_dword(bridge, PCI_CB_IO_LIMIT_0,
                                        region.end);
        }

        pcibios_resource_to_bus(bridge, &region, bus->resource[1]);
        if (bus->resource[1]->flags & IORESOURCE_IO) {
                printk("  IO window: %08lx-%08lx\n",
                        region.start, region.end);
                pci_write_config_dword(bridge, PCI_CB_IO_BASE_1,
                                        region.start);
                pci_write_config_dword(bridge, PCI_CB_IO_LIMIT_1,
                                        region.end);
        }

        pcibios_resource_to_bus(bridge, &region, bus->resource[2]);
        if (bus->resource[2]->flags & IORESOURCE_MEM) {
                printk("  PREFETCH window: %08lx-%08lx\n",
                        region.start, region.end);
                pci_write_config_dword(bridge, PCI_CB_MEMORY_BASE_0,
                                        region.start);
                pci_write_config_dword(bridge, PCI_CB_MEMORY_LIMIT_0,
                                        region.end);
        }

        pcibios_resource_to_bus(bridge, &region, bus->resource[3]);
        if (bus->resource[3]->flags & IORESOURCE_MEM) {
                printk("  MEM window: %08lx-%08lx\n",
                        region.start, region.end);
                pci_write_config_dword(bridge, PCI_CB_MEMORY_BASE_1,
                                        region.start);
                pci_write_config_dword(bridge, PCI_CB_MEMORY_LIMIT_1,
                                        region.end);
        }
}

/* Initialize bridges with base/limit values we have collected.
   PCI-to-PCI Bridge Architecture Specification rev. 1.1 (1998)
   requires that if there is no I/O ports or memory behind the
   bridge, corresponding range must be turned off by writing base
   value greater than limit to the bridge's base/limit registers.

   Note: care must be taken when updating I/O base/limit registers
   of bridges which support 32-bit I/O. This update requires two
   config space writes, so it's quite possible that an I/O window of
   the bridge will have some undesirable address (e.g. 0) after the
   first write. Ditto 64-bit prefetchable MMIO.  */
static void __devinit
pci_setup_bridge(struct pci_bus *bus)
{
        struct pci_dev *bridge = bus->self;
        struct pci_bus_region region;
        u32 l, io_upper16;

        DBGC((KERN_INFO "PCI: Bus %d, bridge: %s\n",
                        bus->number, pci_name(bridge)));

        /* Set up the top and bottom of the PCI I/O segment for this bus. */
        pcibios_resource_to_bus(bridge, &region, bus->resource[0]);
        if (bus->resource[0]->flags & IORESOURCE_IO) {
                pci_read_config_dword(bridge, PCI_IO_BASE, &l);
                l &= 0xffff0000;
                l |= (region.start >> 8) & 0x00f0;
                l |= region.end & 0xf000;
                /* Set up upper 16 bits of I/O base/limit. */
                io_upper16 = (region.end & 0xffff0000) | (region.start >> 16);
                DBGC((KERN_INFO "  IO window: %04lx-%04lx\n",
                                region.start, region.end));
        }
        else {
                /* Clear upper 16 bits of I/O base/limit. */
                io_upper16 = 0;
                l = 0x00f0;
                DBGC((KERN_INFO "  IO window: disabled.\n"));
        }
        /* Temporarily disable the I/O range before updating PCI_IO_BASE. */
        pci_write_config_dword(bridge, PCI_IO_BASE_UPPER16, 0x0000ffff);
        /* Update lower 16 bits of I/O base/limit. */
        pci_write_config_dword(bridge, PCI_IO_BASE, l);
        /* Update upper 16 bits of I/O base/limit. */
        pci_write_config_dword(bridge, PCI_IO_BASE_UPPER16, io_upper16);

        /* Set up the top and bottom of the PCI Memory segment
           for this bus. */
        pcibios_resource_to_bus(bridge, &region, bus->resource[1]);
        if (bus->resource[1]->flags & IORESOURCE_MEM) {
                l = (region.start >> 16) & 0xfff0;
                l |= region.end & 0xfff00000;
                DBGC((KERN_INFO "  MEM window: %08lx-%08lx\n",
                                region.start, region.end));
        }
        else {
                l = 0x0000fff0;
                DBGC((KERN_INFO "  MEM window: disabled.\n"));
        }
        pci_write_config_dword(bridge, PCI_MEMORY_BASE, l);

        /* Clear out the upper 32 bits of PREF limit.
           If PCI_PREF_BASE_UPPER32 was non-zero, this temporarily
           disables PREF range, which is ok. */
        pci_write_config_dword(bridge, PCI_PREF_LIMIT_UPPER32, 0);

        /* Set up PREF base/limit. */
        pcibios_resource_to_bus(bridge, &region, bus->resource[2]);
        if (bus->resource[2]->flags & IORESOURCE_PREFETCH) {
                l = (region.start >> 16) & 0xfff0;
                l |= region.end & 0xfff00000;
                DBGC((KERN_INFO "  PREFETCH window: %08lx-%08lx\n",
                                region.start, region.end));
        }
        else {
                l = 0x0000fff0;
                DBGC((KERN_INFO "  PREFETCH window: disabled.\n"));
        }
        pci_write_config_dword(bridge, PCI_PREF_MEMORY_BASE, l);

        /* Clear out the upper 32 bits of PREF base. */
        pci_write_config_dword(bridge, PCI_PREF_BASE_UPPER32, 0);

        /* Check if we have VGA behind the bridge.
           Enable ISA in either case (FIXME!). */
        l = (bus->resource[0]->flags & IORESOURCE_BUS_HAS_VGA) ? 0x0c : 0x04;
        pci_write_config_word(bridge, PCI_BRIDGE_CONTROL, l);
}

/* Check whether the bridge supports optional I/O and
   prefetchable memory ranges. If not, the respective
   base/limit registers must be read-only and read as 0. */
static void __devinit
pci_bridge_check_ranges(struct pci_bus *bus)
{
        u16 io;
        u32 pmem;
        struct pci_dev *bridge = bus->self;
        struct resource *b_res;

        b_res = &bridge->resource[PCI_BRIDGE_RESOURCES];
        b_res[1].flags |= IORESOURCE_MEM;

        pci_read_config_word(bridge, PCI_IO_BASE, &io);
        if (!io) {
                pci_write_config_word(bridge, PCI_IO_BASE, 0xf0f0);
                pci_read_config_word(bridge, PCI_IO_BASE, &io);
                pci_write_config_word(bridge, PCI_IO_BASE, 0x0);
        }
        if (io)
                b_res[0].flags |= IORESOURCE_IO;
        /*  DECchip 21050 pass 2 errata: the bridge may miss an address
            disconnect boundary by one PCI data phase.
            Workaround: do not use prefetching on this device. */
        if (bridge->vendor == PCI_VENDOR_ID_DEC && bridge->device == 0x0001)
                return;
        pci_read_config_dword(bridge, PCI_PREF_MEMORY_BASE, &pmem);
        if (!pmem) {
                pci_write_config_dword(bridge, PCI_PREF_MEMORY_BASE,
                                               0xfff0fff0);
                pci_read_config_dword(bridge, PCI_PREF_MEMORY_BASE, &pmem);
                pci_write_config_dword(bridge, PCI_PREF_MEMORY_BASE, 0x0);
        }
        if (pmem)
                b_res[2].flags |= IORESOURCE_MEM | IORESOURCE_PREFETCH;
}

/* Helper function for sizing routines: find first available
   bus resource of a given type. Note: we intentionally skip
   the bus resources which have already been assigned (that is,
   have non-NULL parent resource). */
static struct resource * __devinit
find_free_bus_resource(struct pci_bus *bus, unsigned long type)
{
        int i;
        struct resource *r;
        unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM |
                                  IORESOURCE_PREFETCH;

        for (i = 0; i < PCI_BUS_NUM_RESOURCES; i++) {
                r = bus->resource[i];
                if (r && (r->flags & type_mask) == type && !r->parent)
                        return r;
        }
        return NULL;
}

/* Sizing the IO windows of the PCI-PCI bridge is trivial,
   since these windows have 4K granularity and the IO ranges
   of non-bridge PCI devices are limited to 256 bytes.
   We must be careful with the ISA aliasing though. */
static void __devinit
pbus_size_io(struct pci_bus *bus)
{
        struct pci_dev *dev;
        struct resource *b_res = find_free_bus_resource(bus, IORESOURCE_IO);
        unsigned long size = 0, size1 = 0;

        if (!b_res)
                return;

        list_for_each_entry(dev, &bus->devices, bus_list) {
                int i;

                for (i = 0; i < PCI_NUM_RESOURCES; i++) {
                        struct resource *r = &dev->resource[i];
                        unsigned long r_size;

                        if (r->parent || !(r->flags & IORESOURCE_IO))
                                continue;
                        r_size = r->end - r->start + 1;

                        if (r_size < 0x400)
                                /* Might be re-aligned for ISA */
                                size += r_size;
                        else
                                size1 += r_size;
                }
        }
/* To be fixed in 2.5: we should have sort of HAVE_ISA
   flag in the struct pci_bus. */
#if defined(CONFIG_ISA) || defined(CONFIG_EISA)
        size = (size & 0xff) + ((size & ~0xffUL) << 2);
#endif
        size = ROUND_UP(size + size1, 4096);
        if (!size) {
                b_res->flags = 0;
                return;
        }
        /* Alignment of the IO window is always 4K */
        b_res->start = 4096;
        b_res->end = b_res->start + size - 1;
}

/* Calculate the size of the bus and minimal alignment which
   guarantees that all child resources fit in this size. */
static int __devinit
pbus_size_mem(struct pci_bus *bus, unsigned long mask, unsigned long type)
{
        struct pci_dev *dev;
        unsigned long min_align, align, size;
        unsigned long aligns[12];       /* Alignments from 1Mb to 2Gb */
        int order, max_order;
        struct resource *b_res = find_free_bus_resource(bus, type);

        if (!b_res)
                return 0;

        memset(aligns, 0, sizeof(aligns));
        max_order = 0;
        size = 0;

        list_for_each_entry(dev, &bus->devices, bus_list) {
                int i;
               
                for (i = 0; i < PCI_NUM_RESOURCES; i++) {
                        struct resource *r = &dev->resource[i];
                        unsigned long r_size;

                        if (r->parent || (r->flags & mask) != type)
                                continue;
                        r_size = r->end - r->start + 1;
                        /* For bridges size != alignment */
                        align = (i < PCI_BRIDGE_RESOURCES) ? r_size : r->start;
                        order = __ffs(align) - 20;
                        if (order > 11) {
                                printk(KERN_WARNING "PCI: region %s/%d "
                                       "too large: %lx-%lx\n",
                                       pci_name(dev), i, r->start, r->end);
                                r->flags = 0;
                                continue;
                        }
                        size += r_size;
                        if (order < 0)
                                order = 0;
                        /* Exclude ranges with size > align from
                           calculation of the alignment. */
                        if (r_size == align)
                                aligns[order] += align;
                        if (order > max_order)
                                max_order = order;
                }
        }

        align = 0;
        min_align = 0;
        for (order = 0; order <= max_order; order++) {
                unsigned long align1 = 1UL << (order + 20);

                if (!align)
                        min_align = align1;
                else if (ROUND_UP(align + min_align, min_align) < align1)
                        min_align = align1 >> 1;
                align += aligns[order];
        }
        size = ROUND_UP(size, min_align);
        if (!size) {
                b_res->flags = 0;
                return 1;
        }
        b_res->start = min_align;
        b_res->end = size + min_align - 1;
        return 1;
}

static void __devinit
pci_bus_size_cardbus(struct pci_bus *bus)
{
        struct pci_dev *bridge = bus->self;
        struct resource *b_res = &bridge->resource[PCI_BRIDGE_RESOURCES];
        u16 ctrl;

        /*
         * Reserve some resources for CardBus.  We reserve
         * a fixed amount of bus space for CardBus bridges.
         */
        b_res[0].start = CARDBUS_IO_SIZE;
        b_res[0].end = b_res[0].start + CARDBUS_IO_SIZE - 1;
        b_res[0].flags |= IORESOURCE_IO;

        b_res[1].start = CARDBUS_IO_SIZE;
        b_res[1].end = b_res[1].start + CARDBUS_IO_SIZE - 1;
        b_res[1].flags |= IORESOURCE_IO;

        /*
         * Check whether prefetchable memory is supported
         * by this bridge.
         */
        pci_read_config_word(bridge, PCI_CB_BRIDGE_CONTROL, &ctrl);
        if (!(ctrl & PCI_CB_BRIDGE_CTL_PREFETCH_MEM0)) {
                ctrl |= PCI_CB_BRIDGE_CTL_PREFETCH_MEM0;
                pci_write_config_word(bridge, PCI_CB_BRIDGE_CONTROL, ctrl);
                pci_read_config_word(bridge, PCI_CB_BRIDGE_CONTROL, &ctrl);
        }

        /*
         * If we have prefetchable memory support, allocate
         * two regions.  Otherwise, allocate one region of
         * twice the size.
         */
        if (ctrl & PCI_CB_BRIDGE_CTL_PREFETCH_MEM0) {
                b_res[2].start = CARDBUS_MEM_SIZE;
                b_res[2].end = b_res[2].start + CARDBUS_MEM_SIZE - 1;
                b_res[2].flags |= IORESOURCE_MEM | IORESOURCE_PREFETCH;

                b_res[3].start = CARDBUS_MEM_SIZE;
                b_res[3].end = b_res[3].start + CARDBUS_MEM_SIZE - 1;
                b_res[3].flags |= IORESOURCE_MEM;
        } else {
                b_res[3].start = CARDBUS_MEM_SIZE * 2;
                b_res[3].end = b_res[3].start + CARDBUS_MEM_SIZE * 2 - 1;
                b_res[3].flags |= IORESOURCE_MEM;
        }
}

void __devinit
pci_bus_size_bridges(struct pci_bus *bus)
{
        struct pci_dev *dev;
        unsigned long mask, prefmask;

        list_for_each_entry(dev, &bus->devices, bus_list) {
                struct pci_bus *b = dev->subordinate;
                if (!b)
                        continue;

                switch (dev->class >> 8) {
                case PCI_CLASS_BRIDGE_CARDBUS:
                        pci_bus_size_cardbus(b);
                        break;

                case PCI_CLASS_BRIDGE_PCI:
                default:
                        pci_bus_size_bridges(b);
                        break;
                }
        }

        /* The root bus? */
        if (!bus->self)
                return;

        switch (bus->self->class >> 8) {
        case PCI_CLASS_BRIDGE_CARDBUS:
                /* don't size cardbuses yet. */
                break;

        case PCI_CLASS_BRIDGE_PCI:
                pci_bridge_check_ranges(bus);
        default:
                pbus_size_io(bus);
                /* If the bridge supports prefetchable range, size it
                   separately. If it doesn't, or its prefetchable window
                   has already been allocated by arch code, try
                   non-prefetchable range for both types of PCI memory
                   resources. */
                mask = IORESOURCE_MEM;
                prefmask = IORESOURCE_MEM | IORESOURCE_PREFETCH;
                if (pbus_size_mem(bus, prefmask, prefmask))
                        mask = prefmask; /* Success, size non-prefetch only. */
                pbus_size_mem(bus, mask, IORESOURCE_MEM);
                break;
        }
}
EXPORT_SYMBOL(pci_bus_size_bridges);

void __devinit
pci_bus_assign_resources(struct pci_bus *bus)
{
        struct pci_bus *b;
        int found_vga = pbus_assign_resources_sorted(bus);
        struct pci_dev *dev;

        if (found_vga) {
                /* Propagate presence of the VGA to upstream bridges */
                for (b = bus; b->parent; b = b->parent) {
                        b->resource[0]->flags |= IORESOURCE_BUS_HAS_VGA;
                }
        }
        list_for_each_entry(dev, &bus->devices, bus_list) {
                b = dev->subordinate;
                if (!b)
                        continue;

                pci_bus_assign_resources(b);

                switch (dev->class >> 8) {
                case PCI_CLASS_BRIDGE_PCI:
                        pci_setup_bridge(b);
                        break;

                case PCI_CLASS_BRIDGE_CARDBUS:
                        pci_setup_cardbus(b);
                        break;

                default:
                        printk(KERN_INFO "PCI: not setting up bridge %s "
                               "for bus %d\n", pci_name(dev), b->number);
                        break;
                }
        }
}
EXPORT_SYMBOL(pci_bus_assign_resources);

void __init
pci_assign_unassigned_resources(void)
{
        struct list_head *ln;

        /* Depth first, calculate sizes and alignments of all
           subordinate buses. */
        for(ln=pci_root_buses.next; ln != &pci_root_buses; ln=ln->next)
                pci_bus_size_bridges(pci_bus_b(ln));
        /* Depth last, allocate resources and update the hardware. */
        for(ln=pci_root_buses.next; ln != &pci_root_buses; ln=ln->next) {
                pci_bus_assign_resources(pci_bus_b(ln));
                pci_enable_bridges(pci_bus_b(ln));
        }
}