/*
 *      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 <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>


static void pbus_assign_resources_sorted(const struct pci_bus *bus)
{
        struct pci_dev *dev;
        struct resource *res;
        struct resource_list head, *list, *tmp;
        int idx;

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

                /* Don't touch classless devices or host bridges or ioapics.  */
                if (class == PCI_CLASS_NOT_DEFINED ||
                    class == PCI_CLASS_BRIDGE_HOST)
                        continue;

                /* Don't touch ioapic devices already enabled by firmware */
                if (class == PCI_CLASS_SYSTEM_PIC) {
                        u16 command;
                        pci_read_config_word(dev, PCI_COMMAND, &command);
                        if (command & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY))
                                continue;
                }

                pdev_sort_resources(dev, &head);
        }

        for (list = head.next; list;) {
                res = list->res;
                idx = res - &list->dev->resource[0];
                if (pci_assign_resource(list->dev, idx)) {
                        /* FIXME: get rid of this */
                        res->start = 0;
                        res->end = 0;
                        res->flags = 0;
                }
                tmp = list;
                list = list->next;
                kfree(tmp);
        }
}

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

        dev_info(&bridge->dev, "CardBus bridge, secondary bus %04x:%02x\n",
                 pci_domain_nr(bus), bus->number);

        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.
                 */
                dev_info(&bridge->dev, "  IO window: %#08lx-%#08lx\n",
                       (unsigned long)region.start,
                       (unsigned long)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) {
                dev_info(&bridge->dev, "  IO window: %#08lx-%#08lx\n",
                       (unsigned long)region.start,
                       (unsigned long)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) {
                dev_info(&bridge->dev, "  PREFETCH window: %#08lx-%#08lx\n",
                       (unsigned long)region.start,
                       (unsigned long)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) {
                dev_info(&bridge->dev, "  MEM window: %#08lx-%#08lx\n",
                       (unsigned long)region.start,
                       (unsigned long)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);
        }
}
EXPORT_SYMBOL(pci_setup_cardbus);

/* 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 pci_setup_bridge(struct pci_bus *bus)
{
        struct pci_dev *bridge = bus->self;
        struct pci_bus_region region;
        u32 l, bu, lu, io_upper16;

        if (pci_is_enabled(bridge))
                return;

        dev_info(&bridge->dev, "PCI bridge, secondary bus %04x:%02x\n",
                 pci_domain_nr(bus), bus->number);

        /* 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);
                dev_info(&bridge->dev, "  IO window: %#04lx-%#04lx\n",
                    (unsigned long)region.start,
                    (unsigned long)region.end);
        }
        else {
                /* Clear upper 16 bits of I/O base/limit. */
                io_upper16 = 0;
                l = 0x00f0;
                dev_info(&bridge->dev, "  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;
                dev_info(&bridge->dev, "  MEM window: %#08lx-%#08lx\n",
                    (unsigned long)region.start,
                    (unsigned long)region.end);
        }
        else {
                l = 0x0000fff0;
                dev_info(&bridge->dev, "  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. */
        bu = lu = 0;
        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;
                bu = upper_32_bits(region.start);
                lu = upper_32_bits(region.end);
                dev_info(&bridge->dev, "  PREFETCH window: %#016llx-%#016llx\n",
                    (unsigned long long)region.start,
                    (unsigned long long)region.end);
        }
        else {
                l = 0x0000fff0;
                dev_info(&bridge->dev, "  PREFETCH window: disabled\n");
        }
        pci_write_config_dword(bridge, PCI_PREF_MEMORY_BASE, l);

        /* Set the upper 32 bits of PREF base & limit. */
        pci_write_config_dword(bridge, PCI_PREF_BASE_UPPER32, bu);
        pci_write_config_dword(bridge, PCI_PREF_LIMIT_UPPER32, lu);

        pci_write_config_word(bridge, PCI_BRIDGE_CONTROL, bus->bridge_ctl);
}

/* 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 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 *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 == &ioport_resource || r == &iomem_resource)
                        continue;
                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 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 = resource_size(r);

                        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 = ALIGN(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;
        b_res->flags |= IORESOURCE_STARTALIGN;
}

/* Calculate the size of the bus and minimal alignment which
   guarantees that all child resources fit in this size. */
static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, unsigned long type)
{
        struct pci_dev *dev;
        resource_size_t min_align, align, size;
        resource_size_t 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];
                        resource_size_t r_size;

                        if (r->parent || (r->flags & mask) != type)
                                continue;
                        r_size = resource_size(r);
                        /* For bridges size != alignment */
                        align = resource_alignment(r);
                        order = __ffs(align) - 20;
                        if (order > 11) {
                                dev_warn(&dev->dev, "BAR %d bad alignment %llx: "
                                         "%pR\n", i, (unsigned long long)align, r);
                                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++) {
                resource_size_t align1 = 1;

                align1 <<= (order + 20);

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

static void 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 = 0;
        b_res[0].end = pci_cardbus_io_size - 1;
        b_res[0].flags |= IORESOURCE_IO | IORESOURCE_SIZEALIGN;

        b_res[1].start = 0;
        b_res[1].end = pci_cardbus_io_size - 1;
        b_res[1].flags |= IORESOURCE_IO | IORESOURCE_SIZEALIGN;

        /*
         * 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 = 0;
                b_res[2].end = pci_cardbus_mem_size - 1;
                b_res[2].flags |= IORESOURCE_MEM | IORESOURCE_PREFETCH | IORESOURCE_SIZEALIGN;

                b_res[3].start = 0;
                b_res[3].end = pci_cardbus_mem_size - 1;
                b_res[3].flags |= IORESOURCE_MEM | IORESOURCE_SIZEALIGN;
        } else {
                b_res[3].start = 0;
                b_res[3].end = pci_cardbus_mem_size * 2 - 1;
                b_res[3].flags |= IORESOURCE_MEM | IORESOURCE_SIZEALIGN;
        }
}

void __ref 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 __ref pci_bus_assign_resources(const struct pci_bus *bus)
{
        struct pci_bus *b;
        struct pci_dev *dev;

        pbus_assign_resources_sorted(bus);

        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:
                        dev_info(&dev->dev, "not setting up bridge for bus "
                                 "%04x:%02x\n", pci_domain_nr(b), b->number);
                        break;
                }
        }
}
EXPORT_SYMBOL(pci_bus_assign_resources);

static void pci_bus_dump_res(struct pci_bus *bus)
{
        int i;

        for (i = 0; i < PCI_BUS_NUM_RESOURCES; i++) {
                struct resource *res = bus->resource[i];
                if (!res || !res->end)
                        continue;

                dev_printk(KERN_DEBUG, &bus->dev, "resource %d %s %pR\n", i,
                           (res->flags & IORESOURCE_IO) ? "io: " :
                            ((res->flags & IORESOURCE_PREFETCH)? "pref mem":"mem:"),
                           res);
        }
}

static void pci_bus_dump_resources(struct pci_bus *bus)
{
        struct pci_bus *b;
        struct pci_dev *dev;


        pci_bus_dump_res(bus);

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

                pci_bus_dump_resources(b);
        }
}

void __init
pci_assign_unassigned_resources(void)
{
        struct pci_bus *bus;

        /* Depth first, calculate sizes and alignments of all
           subordinate buses. */
        list_for_each_entry(bus, &pci_root_buses, node) {
                pci_bus_size_bridges(bus);
        }
        /* Depth last, allocate resources and update the hardware. */
        list_for_each_entry(bus, &pci_root_buses, node) {
                pci_bus_assign_resources(bus);
                pci_enable_bridges(bus);
        }

        /* dump the resource on buses */
        list_for_each_entry(bus, &pci_root_buses, node) {
                pci_bus_dump_resources(bus);
        }
}