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/*
 * probe.c - PCI detection and setup code
 */


#include <linuxcomp.h>

#include <linux/init.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/module.h>

//#define DEBUG

#ifdef DEBUG
#define DBG(x...) printk(x)
#else
#define DBG(x...)
#endif

#define CARDBUS_LATENCY_TIMER   176     /* secondary latency timer */
#define CARDBUS_RESERVE_BUSNR   3

/* Ugh.  Need to stop exporting this to modules. */
LIST_HEAD(pci_root_buses);
EXPORT_SYMBOL(pci_root_buses);

LIST_HEAD(pci_devices);

/*
 * Translate the low bits of the PCI base
 * to the resource type
 */

static inline unsigned int pci_calc_resource_flags(unsigned int flags)
{
        if (flags & PCI_BASE_ADDRESS_SPACE_IO)
                return IORESOURCE_IO;

        if (flags & PCI_BASE_ADDRESS_MEM_PREFETCH)
                return IORESOURCE_MEM | IORESOURCE_PREFETCH;

        return IORESOURCE_MEM;
}

/*
 * Find the extent of a PCI decode..
 */

static u32 pci_size(u32 base, u32 maxbase, unsigned long mask)
{
        u32 size = mask & maxbase;      /* Find the significant bits */
        if (!size)
                return 0;

        /* Get the lowest of them to find the decode size, and
           from that the extent.  */

        size = (size & ~(size-1)) - 1;

        /* base == maxbase can be valid only if the BAR has
           already been programmed with all 1s.  */

        if (base == maxbase && ((base | size) & mask) != mask)
                return 0;

        return size;
}

static void pci_read_bases(struct pci_dev *dev, unsigned int howmany, int rom)
{
        unsigned int pos, reg, next;
        u32 l, sz;
        struct resource *res;

        for(pos=0; pos<howmany; pos = next) {
                next = pos+1;
                res = &dev->resource[pos];
                res->name = pci_name(dev);
                reg = PCI_BASE_ADDRESS_0 + (pos << 2);
                pci_read_config_dword(dev, reg, &l);
                pci_write_config_dword(dev, reg, ~0);
                pci_read_config_dword(dev, reg, &sz);
                pci_write_config_dword(dev, reg, l);
                if (!sz || sz == 0xffffffff)
                        continue;
                if (l == 0xffffffff)
                        l = 0;
                if ((l & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_MEMORY) {
                        sz = pci_size(l, sz, PCI_BASE_ADDRESS_MEM_MASK);
                        if (!sz)
                                continue;
                        res->start = l & PCI_BASE_ADDRESS_MEM_MASK;
                        res->flags |= l & ~PCI_BASE_ADDRESS_MEM_MASK;
                } else {
                        sz = pci_size(l, sz, PCI_BASE_ADDRESS_IO_MASK & 0xffff);
                        if (!sz)
                                continue;
                        res->start = l & PCI_BASE_ADDRESS_IO_MASK;
                        res->flags |= l & ~PCI_BASE_ADDRESS_IO_MASK;
                }
                res->end = res->start + (unsigned long) sz;
                res->flags |= pci_calc_resource_flags(l);
                if ((l & (PCI_BASE_ADDRESS_SPACE | PCI_BASE_ADDRESS_MEM_TYPE_MASK))
                    == (PCI_BASE_ADDRESS_SPACE_MEMORY | PCI_BASE_ADDRESS_MEM_TYPE_64)) {
                        pci_read_config_dword(dev, reg+4, &l);
                        next++;
#if BITS_PER_LONG == 64
                        res->start |= ((unsigned long) l) << 32;
                        res->end = res->start + sz;
                        pci_write_config_dword(dev, reg+4, ~0);
                        pci_read_config_dword(dev, reg+4, &sz);
                        pci_write_config_dword(dev, reg+4, l);
                        if (~sz)
                                res->end = res->start + 0xffffffff +
                                                (((unsigned long) ~sz) << 32);
#else
                        if (l) {
                                printk(KERN_ERR "PCI: Unable to handle 64-bit address for device %s\n", pci_name(dev));
                                res->start = 0;
                                res->flags = 0;
                                continue;
                        }
#endif
                }
        }
        if (rom) {
                dev->rom_base_reg = rom;
                res = &dev->resource[PCI_ROM_RESOURCE];
                res->name = pci_name(dev);
                pci_read_config_dword(dev, rom, &l);
                pci_write_config_dword(dev, rom, ~PCI_ROM_ADDRESS_ENABLE);
                pci_read_config_dword(dev, rom, &sz);
                pci_write_config_dword(dev, rom, l);
                if (l == 0xffffffff)
                        l = 0;
                if (sz && sz != 0xffffffff) {
                        sz = pci_size(l, sz, PCI_ROM_ADDRESS_MASK);
                        if (sz) {
                                res->flags = (l & PCI_ROM_ADDRESS_ENABLE) |
                                  IORESOURCE_MEM | IORESOURCE_PREFETCH |
                                  IORESOURCE_READONLY | IORESOURCE_CACHEABLE;
                                res->start = l & PCI_ROM_ADDRESS_MASK;
                                res->end = res->start + (unsigned long) sz;
                        }
                }
        }
}

void __devinit pci_read_bridge_bases(struct pci_bus *child)
{
        struct pci_dev *dev = child->self;
        u8 io_base_lo, io_limit_lo;
        u16 mem_base_lo, mem_limit_lo;
        unsigned long base, limit;
        struct resource *res;
        int i;

        if (!dev)               /* It's a host bus, nothing to read */
                return;

        if (dev->transparent) {
                printk("Transparent bridge - %s\n", pci_name(dev));
                for(i = 0; i < PCI_BUS_NUM_RESOURCES; i++)
                        child->resource[i] = child->parent->resource[i];
                return;
        }

        for(i=0; i<3; i++)
                child->resource[i] = &dev->resource[PCI_BRIDGE_RESOURCES+i];

        res = child->resource[0];
        pci_read_config_byte(dev, PCI_IO_BASE, &io_base_lo);
        pci_read_config_byte(dev, PCI_IO_LIMIT, &io_limit_lo);
        base = (io_base_lo & PCI_IO_RANGE_MASK) << 8;
        limit = (io_limit_lo & PCI_IO_RANGE_MASK) << 8;

        if ((io_base_lo & PCI_IO_RANGE_TYPE_MASK) == PCI_IO_RANGE_TYPE_32) {
                u16 io_base_hi, io_limit_hi;
                pci_read_config_word(dev, PCI_IO_BASE_UPPER16, &io_base_hi);
                pci_read_config_word(dev, PCI_IO_LIMIT_UPPER16, &io_limit_hi);
                base |= (io_base_hi << 16);
                limit |= (io_limit_hi << 16);
        }

        if (base && base <= limit) {
                res->flags = (io_base_lo & PCI_IO_RANGE_TYPE_MASK) | IORESOURCE_IO;
                res->start = base;
                res->end = limit + 0xfff;
        }

        res = child->resource[1];
        pci_read_config_word(dev, PCI_MEMORY_BASE, &mem_base_lo);
        pci_read_config_word(dev, PCI_MEMORY_LIMIT, &mem_limit_lo);
        base = (mem_base_lo & PCI_MEMORY_RANGE_MASK) << 16;
        limit = (mem_limit_lo & PCI_MEMORY_RANGE_MASK) << 16;
        if (base && base <= limit) {
                res->flags = (mem_base_lo & PCI_MEMORY_RANGE_TYPE_MASK) | IORESOURCE_MEM;
                res->start = base;
                res->end = limit + 0xfffff;
        }

        res = child->resource[2];
        pci_read_config_word(dev, PCI_PREF_MEMORY_BASE, &mem_base_lo);
        pci_read_config_word(dev, PCI_PREF_MEMORY_LIMIT, &mem_limit_lo);
        base = (mem_base_lo & PCI_PREF_RANGE_MASK) << 16;
        limit = (mem_limit_lo & PCI_PREF_RANGE_MASK) << 16;

        if ((mem_base_lo & PCI_PREF_RANGE_TYPE_MASK) == PCI_PREF_RANGE_TYPE_64) {
                u32 mem_base_hi, mem_limit_hi;
                pci_read_config_dword(dev, PCI_PREF_BASE_UPPER32, &mem_base_hi);
                pci_read_config_dword(dev, PCI_PREF_LIMIT_UPPER32, &mem_limit_hi);
#if BITS_PER_LONG == 64
                base |= ((long) mem_base_hi) << 32;
                limit |= ((long) mem_limit_hi) << 32;
#else
                if (mem_base_hi || mem_limit_hi) {
                        printk(KERN_ERR "PCI: Unable to handle 64-bit address space for %s\n", child->name);
                        return;
                }
#endif
        }
        if (base && base <= limit) {
                res->flags = (mem_base_lo & PCI_MEMORY_RANGE_TYPE_MASK) | IORESOURCE_MEM | IORESOURCE_PREFETCH;
                res->start = base;
                res->end = limit + 0xfffff;
        }
}

static struct pci_bus * __devinit pci_alloc_bus(void)
{
        struct pci_bus *b;

        b = kmalloc(sizeof(*b), GFP_KERNEL);
        if (b) {
                memset(b, 0, sizeof(*b));
                INIT_LIST_HEAD(&b->node);
                INIT_LIST_HEAD(&b->children);
                INIT_LIST_HEAD(&b->devices);
        }
        return b;
}

static struct pci_bus * __devinit
pci_alloc_child_bus(struct pci_bus *parent, struct pci_dev *bridge, int busnr)
{
        struct pci_bus *child;

        /*
         * Allocate a new bus, and inherit stuff from the parent..
         */

        child = pci_alloc_bus();

        if (child) {
                int i;

                child->self = bridge;
                child->parent = parent;
                child->ops = parent->ops;
                child->sysdata = parent->sysdata;
                child->dev = &bridge->dev;

                /*
                 * Set up the primary, secondary and subordinate
                 * bus numbers.
                 */

                child->number = child->secondary = busnr;
                child->primary = parent->secondary;
                child->subordinate = 0xff;

                /* Set up default resource pointers and names.. */
                for (i = 0; i < 4; i++) {
                        child->resource[i] = &bridge->resource[PCI_BRIDGE_RESOURCES+i];
                        child->resource[i]->name = child->name;
                }

                bridge->subordinate = child;
        }

        return child;
}

struct pci_bus * __devinit pci_add_new_bus(struct pci_bus *parent, struct pci_dev *dev, int busnr)
{
        struct pci_bus *child;

        child = pci_alloc_child_bus(parent, dev, busnr);
        if (child)
                list_add_tail(&child->node, &parent->children);
        return child;
}

static unsigned int __devinit pci_scan_child_bus(struct pci_bus *bus);

/*
 * If it's a bridge, configure it and scan the bus behind it.
 * For CardBus bridges, we don't scan behind as the devices will
 * be handled by the bridge driver itself.
 *
 * We need to process bridges in two passes -- first we scan those
 * already configured by the BIOS and after we are done with all of
 * them, we proceed to assigning numbers to the remaining buses in
 * order to avoid overlaps between old and new bus numbers.
 */

int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max, int pass)
{
        struct pci_bus *child;
        int is_cardbus = (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS);
        u32 buses;

        pci_read_config_dword(dev, PCI_PRIMARY_BUS, &buses);

        DBG("Scanning behind PCI bridge %s, config %06x, pass %d\n",
            pci_name(dev), buses & 0xffffff, pass);

        if ((buses & 0xffff00) && !pcibios_assign_all_busses() && !is_cardbus) {
                unsigned int cmax;
                /*
                 * Bus already configured by firmware, process it in the first
                 * pass and just note the configuration.
                 */

                if (pass)
                        return max;
                child = pci_alloc_child_bus(bus, dev, 0);
                child->primary = buses & 0xFF;
                child->secondary = (buses >> 8) & 0xFF;
                child->subordinate = (buses >> 16) & 0xFF;
                child->number = child->secondary;
                cmax = pci_scan_child_bus(child);
                if (cmax > max) max = cmax;
        } else {
                /*
                 * We need to assign a number to this bus which we always
                 * do in the second pass.
                 */

                if (!pass)
                        return max;

                /* Clear errors */
                pci_write_config_word(dev, PCI_STATUS, 0xffff);

                child = pci_alloc_child_bus(bus, dev, ++max);
                buses = (buses & 0xff000000)
                      | ((unsigned int)(child->primary)     <<  0)
                      | ((unsigned int)(child->secondary)   <<  8)
                      | ((unsigned int)(child->subordinate) << 16);

                /*
                 * yenta.c forces a secondary latency timer of 176.
                 * Copy that behaviour here.
                 */

                if (is_cardbus) {
                        buses &= ~0xff000000;
                        buses |= CARDBUS_LATENCY_TIMER << 24;
                }
                       
                /*
                 * We need to blast all three values with a single write.
                 */

                pci_write_config_dword(dev, PCI_PRIMARY_BUS, buses);

                if (!is_cardbus) {
                        /* Now we can scan all subordinate buses... */
                        max = pci_scan_child_bus(child);
                } else {
                        /*
                         * For CardBus bridges, we leave 4 bus numbers
                         * as cards with a PCI-to-PCI bridge can be
                         * inserted later.
                         */

                        max += CARDBUS_RESERVE_BUSNR;
                }
                /*
                 * Set the subordinate bus number to its real value.
                 */

                child->subordinate = max;
                pci_write_config_byte(dev, PCI_SUBORDINATE_BUS, max);
        }
 
        sprintf26(child->name, (is_cardbus ? "PCI CardBus #%02x" : "PCI Bus #%02x"), child->number);

        return max;
}

/*
 * Read interrupt line and base address registers.
 * The architecture-dependent code can tweak these, of course.
 */

static void pci_read_irq(struct pci_dev *dev)
{
        unsigned char irq;

        pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &irq);
        if (irq)
                pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &irq);
        dev->irq = irq;
}

/**
 * pci_setup_device - fill in class and map information of a device
 * @dev: the device structure to fill
 *
 * Initialize the device structure with information about the device's
 * vendor,class,memory and IO-space addresses,IRQ lines etc.
 * Called at initialisation of the PCI subsystem and by CardBus services.
 * Returns 0 on success and -1 if unknown type of device (not normal, bridge
 * or CardBus).
 */

static int pci_setup_device(struct pci_dev * dev)
{
        u32 class;

        dev->slot_name = dev->dev.bus_id;
        sprintf26(pci_name(dev), "%04x:%02x:%02x.%d", pci_domain_nr(dev->bus),
                dev->bus->number, PCI_SLOT(dev->devfn), PCI_FUNC(dev->devfn));

        INIT_LIST_HEAD(&dev->pools);

        pci_read_config_dword(dev, PCI_CLASS_REVISION, &class);
        class >>= 8;                                /* upper 3 bytes */
        dev->class = class;
        class >>= 8;

        DBG("Found %02x:%02x [%04x/%04x] %06x %02x\n", dev->bus->number,
            dev->devfn, dev->vendor, dev->device, class, dev->hdr_type);

        /* "Unknown power state" */
        dev->current_state = 4;

        switch (dev->hdr_type) {                    /* header type */
        case PCI_HEADER_TYPE_NORMAL:                /* standard header */
                if (class == PCI_CLASS_BRIDGE_PCI)
                        goto bad;
                pci_read_irq(dev);
                pci_read_bases(dev, 6, PCI_ROM_ADDRESS);
                pci_read_config_word(dev, PCI_SUBSYSTEM_VENDOR_ID, &dev->subsystem_vendor);
                pci_read_config_word(dev, PCI_SUBSYSTEM_ID, &dev->subsystem_device);
                break;

        case PCI_HEADER_TYPE_BRIDGE:                /* bridge header */
                if (class != PCI_CLASS_BRIDGE_PCI)
                        goto bad;
                /* The PCI-to-PCI bridge spec requires that subtractive
                   decoding (i.e. transparent) bridge must have programming
                   interface code of 0x01. */

                dev->transparent = ((dev->class & 0xff) == 1);
                pci_read_bases(dev, 2, PCI_ROM_ADDRESS1);
                break;

        case PCI_HEADER_TYPE_CARDBUS:               /* CardBus bridge header */
                if (class != PCI_CLASS_BRIDGE_CARDBUS)
                        goto bad;
                pci_read_irq(dev);
                pci_read_bases(dev, 1, 0);
                pci_read_config_word(dev, PCI_CB_SUBSYSTEM_VENDOR_ID, &dev->subsystem_vendor);
                pci_read_config_word(dev, PCI_CB_SUBSYSTEM_ID, &dev->subsystem_device);
                break;

        default:                                    /* unknown header */
                printk(KERN_ERR "PCI: device %s has unknown header type %02x, ignoring.\n",
                        pci_name(dev), dev->hdr_type);
                return -1;

        bad:
                printk(KERN_ERR "PCI: %s: class %x doesn't match header type %02x. Ignoring class.\n",
                       pci_name(dev), class, dev->hdr_type);
                dev->class = PCI_CLASS_NOT_DEFINED;
        }

        /* We found a fine healthy device, go go go... */
        return 0;
}

/**
 * pci_release_dev - free a pci device structure when all users of it are finished.
 * @dev: device that's been disconnected
 *
 * Will be called only by the device core when all users of this pci device are
 * done.
 */

static void pci_release_dev(struct device *dev)
{
        struct pci_dev *pci_dev;

        pci_dev = to_pci_dev(dev);
        kfree(pci_dev);
}

/*
 * Read the config data for a PCI device, sanity-check it
 * and fill in the dev structure...
 */

static struct pci_dev * __devinit
pci_scan_device(struct pci_bus *bus, int devfn)
{
        struct pci_dev *dev;
        u32 l;
        u8 hdr_type;

        if (pci_bus_read_config_byte(bus, devfn, PCI_HEADER_TYPE, &hdr_type))
                return NULL;

        if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, &l))
                return NULL;

        /* some broken boards return 0 or ~0 if a slot is empty: */
        if (l == 0xffffffff || l == 0x00000000 ||
            l == 0x0000ffff || l == 0xffff0000)
                return NULL;

        dev = kmalloc(sizeof(struct pci_dev), GFP_KERNEL);
        if (!dev)
                return NULL;

        memset(dev, 0, sizeof(struct pci_dev));
        dev->bus = bus;
        dev->sysdata = bus->sysdata;
        dev->dev.parent = bus->dev;
        dev->dev.bus = &pci_bus_type;
        dev->devfn = devfn;
        dev->hdr_type = hdr_type & 0x7f;
        dev->multifunction = !!(hdr_type & 0x80);
        dev->vendor = l & 0xffff;
        dev->device = (l >> 16) & 0xffff;

        /* Assume 32-bit PCI; let 64-bit PCI cards (which are far rarer)
           set this higher, assuming the system even supports it.  */

        dev->dma_mask = 0xffffffff;
        dev->consistent_dma_mask = 0xffffffff;
        if (pci_setup_device(dev) < 0) {
                kfree(dev);
                return NULL;
        }
        device_initialize(&dev->dev);
        dev->dev.release = pci_release_dev;
        pci_dev_get(dev);

        pci_name_device(dev);

        dev->dev.dma_mask = &dev->dma_mask;

        return dev;
}

/**
 * pci_scan_slot - scan a PCI slot on a bus for devices.
 * @bus: PCI bus to scan
 * @devfn: slot number to scan (must have zero function.)
 *
 * Scan a PCI slot on the specified PCI bus for devices, adding
 * discovered devices to the @bus->devices list.  New devices
 * will have an empty dev->global_list head.
 */

int __devinit pci_scan_slot(struct pci_bus *bus, int devfn)
{
        int func, nr = 0;

        for (func = 0; func < 8; func++, devfn++) {
                struct pci_dev *dev;

                dev = pci_scan_device(bus, devfn);
                if (func == 0) {
                        if (!dev)
                                break;
                } else {
                        if (!dev)
                                continue;
                        dev->multifunction = 1;
                }

                /* Fix up broken headers */
                pci_fixup_device(PCI_FIXUP_HEADER, dev);

                /*
                 * Add the device to our list of discovered devices
                 * and the bus list for fixup functions, etc.
                 */

                INIT_LIST_HEAD(&dev->global_list);
                list_add_tail(&dev->bus_list, &bus->devices);
                nr++;

                /*
                 * If this is a single function device,
                 * don't scan past the first function.
                 */

                if (!dev->multifunction)
                        break;
        }
        return nr;
}

static unsigned int __devinit pci_scan_child_bus(struct pci_bus *bus)
{
        unsigned int devfn, pass, max = bus->secondary;
        struct pci_dev *dev;

        DBG("Scanning bus %02x\n", bus->number);

        /* Go find them, Rover! */
        for (devfn = 0; devfn < 0x100; devfn += 8)
                pci_scan_slot(bus, devfn);

        /*
         * After performing arch-dependent fixup of the bus, look behind
         * all PCI-to-PCI bridges on this bus.
         */

        DBG("Fixups for bus %02x\n", bus->number);
        pcibios_fixup_bus(bus);
        for (pass=0; pass < 2; pass++)
                list_for_each_entry(dev, &bus->devices, bus_list) {
                        if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE ||
                            dev->hdr_type == PCI_HEADER_TYPE_CARDBUS)
                                max = pci_scan_bridge(bus, dev, max, pass);
                }

        /*
         * We've scanned the bus and so we know all about what's on
         * the other side of any bridges that may be on this bus plus
         * any devices.
         *
         * Return how far we've got finding sub-buses.
         */

        DBG("Bus scan for %02x returning with max=%02x\n", bus->number, max);
        return max;
}

unsigned int __devinit pci_do_scan_bus(struct pci_bus *bus)
{
        unsigned int max;

        max = pci_scan_child_bus(bus);

        /*
         * Make the discovered devices available.
         */

        pci_bus_add_devices(bus);

        return max;
}

struct pci_bus * __devinit pci_scan_bus_parented(struct device *parent, int bus, struct pci_ops *ops, void *sysdata)
{
        struct pci_bus *b;

        b = pci_alloc_bus();
        if (!b)
                return NULL;

        b->dev = kmalloc(sizeof(*(b->dev)),GFP_KERNEL);
        if (!b->dev){
                kfree(b);
                return NULL;
        }

        b->sysdata = sysdata;
        b->ops = ops;

        if (pci_find_bus(pci_domain_nr(b), bus)) {
                /* If we already got to this bus through a different bridge, ignore it */
                DBG("PCI: Bus %02x already known\n", bus);
                kfree(b->dev);
                kfree(b);
                return NULL;
        }

        list_add_tail(&b->node, &pci_root_buses);

        memset(b->dev,0,sizeof(*(b->dev)));
        b->dev->parent = parent;
        sprintf26(b->dev->bus_id,"pci%04x:%02x", pci_domain_nr(b), bus);
        device_register(b->dev);

        b->number = b->secondary = bus;
        b->resource[0] = &ioport_resource;
        b->resource[1] = &iomem_resource;

        b->subordinate = pci_scan_child_bus(b);

        pci_bus_add_devices(b);

        return b;
}
EXPORT_SYMBOL(pci_scan_bus_parented);

#ifdef CONFIG_HOTPLUG
EXPORT_SYMBOL(pci_add_new_bus);
EXPORT_SYMBOL(pci_do_scan_bus);
EXPORT_SYMBOL(pci_scan_slot);
EXPORT_SYMBOL(pci_scan_bridge);
#endif