isa-bridge.c

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/*
 * Routines for tracking a legacy ISA bridge
 *
 * Copyrigh 2007 Benjamin Herrenschmidt <[email protected]>, IBM Corp.
 *
 * Some bits and pieces moved over from pci_64.c
 *
 * Copyrigh 2003 Anton Blanchard <[email protected]>, IBM Corp.
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#define DEBUG

#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/string.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/notifier.h>

#include <asm/processor.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/pci-bridge.h>
#include <asm/machdep.h>
#include <asm/ppc-pci.h>

unsigned long isa_io_base;  /* NULL if no ISA bus */
EXPORT_SYMBOL(isa_io_base);

/* Cached ISA bridge dev. */
static struct device_node *isa_bridge_devnode;
struct pci_dev *isa_bridge_pcidev;
EXPORT_SYMBOL_GPL(isa_bridge_pcidev);

#define ISA_SPACE_MASK 0x1
#define ISA_SPACE_IO 0x1

static void __devinit pci_process_ISA_OF_ranges(struct device_node *isa_node,
                        unsigned long phb_io_base_phys)
{
    /* We should get some saner parsing here and remove these structs */
    struct pci_address {
        u32 a_hi;
        u32 a_mid;
        u32 a_lo;
    };

    struct isa_address {
        u32 a_hi;
        u32 a_lo;
    };

    struct isa_range {
        struct isa_address isa_addr;
        struct pci_address pci_addr;
        unsigned int size;
    };

    const struct isa_range *range;
    unsigned long pci_addr;
    unsigned int isa_addr;
    unsigned int size;
    int rlen = 0;

    range = of_get_property(isa_node, "ranges", &rlen);
    if (range == NULL || (rlen < sizeof(struct isa_range)))
        goto inval_range;

    /* From "ISA Binding to 1275"
     * The ranges property is laid out as an array of elements,
     * each of which comprises:
     *   cells 0 - 1:   an ISA address
     *   cells 2 - 4:   a PCI address
     *          (size depending on dev->n_addr_cells)
     *   cell 5:        the size of the range
     */
    if ((range->isa_addr.a_hi & ISA_SPACE_MASK) != ISA_SPACE_IO) {
        range++;
        rlen -= sizeof(struct isa_range);
        if (rlen < sizeof(struct isa_range))
            goto inval_range;
    }
    if ((range->isa_addr.a_hi & ISA_SPACE_MASK) != ISA_SPACE_IO)
        goto inval_range;

    isa_addr = range->isa_addr.a_lo;
    pci_addr = (unsigned long) range->pci_addr.a_mid << 32 |
        range->pci_addr.a_lo;

    /* Assume these are both zero. Note: We could fix that and
     * do a proper parsing instead ... oh well, that will do for
     * now as nobody uses fancy mappings for ISA bridges
     */
    if ((pci_addr != 0) || (isa_addr != 0)) {
        printk(KERN_ERR "unexpected isa to pci mapping: %s\n",
               __func__);
        return;
    }

    /* Align size and make sure it's cropped to 64K */
    size = PAGE_ALIGN(range->size);
    if (size > 0x10000)
        size = 0x10000;

    __ioremap_at(phb_io_base_phys, (void *)ISA_IO_BASE,
             size, _PAGE_NO_CACHE|_PAGE_GUARDED);
    return;

inval_range:
    printk(KERN_ERR "no ISA IO ranges or unexpected isa range, "
           "mapping 64k\n");
    __ioremap_at(phb_io_base_phys, (void *)ISA_IO_BASE,
             0x10000, _PAGE_NO_CACHE|_PAGE_GUARDED);
}


void __init isa_bridge_find_early(struct pci_controller *hose)
{
    struct device_node *np, *parent = NULL, *tmp;

    /* If we already have an ISA bridge, bail off */
    if (isa_bridge_devnode != NULL)
        return;

    /* For each "isa" node in the system. Note : we do a search by
     * type and not by name. It might be better to do by name but that's
     * what the code used to do and I don't want to break too much at
     * once. We can look into changing that separately
     */
    for_each_node_by_type(np, "isa") {
        /* Look for our hose being a parent */
        for (parent = of_get_parent(np); parent;) {
            if (parent == hose->dn) {
                of_node_put(parent);
                break;
            }
            tmp = parent;
            parent = of_get_parent(parent);
            of_node_put(tmp);
        }
        if (parent != NULL)
            break;
    }
    if (np == NULL)
        return;
    isa_bridge_devnode = np;

    /* Now parse the "ranges" property and setup the ISA mapping */
    pci_process_ISA_OF_ranges(np, hose->io_base_phys);

    /* Set the global ISA io base to indicate we have an ISA bridge */
    isa_io_base = ISA_IO_BASE;

    pr_debug("ISA bridge (early) is %s\n", np->full_name);
}

static void __devinit isa_bridge_find_late(struct pci_dev *pdev,
                       struct device_node *devnode)
{
    struct pci_controller *hose = pci_bus_to_host(pdev->bus);

    /* Store ISA device node and PCI device */
    isa_bridge_devnode = of_node_get(devnode);
    isa_bridge_pcidev = pdev;

    /* Now parse the "ranges" property and setup the ISA mapping */
    pci_process_ISA_OF_ranges(devnode, hose->io_base_phys);

    /* Set the global ISA io base to indicate we have an ISA bridge */
    isa_io_base = ISA_IO_BASE;

    pr_debug("ISA bridge (late) is %s on %s\n",
         devnode->full_name, pci_name(pdev));
}

static void isa_bridge_remove(void)
{
    pr_debug("ISA bridge removed !\n");

    /* Clear the global ISA io base to indicate that we have no more
     * ISA bridge. Note that drivers don't quite handle that, though
     * we should probably do something about it. But do we ever really
     * have ISA bridges being removed on machines using legacy devices ?
     */
    isa_io_base = ISA_IO_BASE;

    /* Clear references to the bridge */
    of_node_put(isa_bridge_devnode);
    isa_bridge_devnode = NULL;
    isa_bridge_pcidev = NULL;

    /* Unmap the ISA area */
    __iounmap_at((void *)ISA_IO_BASE, 0x10000);
}

static int __devinit isa_bridge_notify(struct notifier_block *nb,
                       unsigned long action, void *data)
{
    struct device *dev = data;
    struct pci_dev *pdev = to_pci_dev(dev);
    struct device_node *devnode = pci_device_to_OF_node(pdev);

    switch(action) {
    case BUS_NOTIFY_ADD_DEVICE:
        /* Check if we have an early ISA device, without PCI dev */
        if (isa_bridge_devnode && isa_bridge_devnode == devnode &&
            !isa_bridge_pcidev) {
            pr_debug("ISA bridge PCI attached: %s\n",
                 pci_name(pdev));
            isa_bridge_pcidev = pdev;
        }

        /* Check if we have no ISA device, and this happens to be one,
         * register it as such if it has an OF device
         */
        if (!isa_bridge_devnode && devnode && devnode->type &&
            !strcmp(devnode->type, "isa"))
            isa_bridge_find_late(pdev, devnode);

        return 0;
    case BUS_NOTIFY_DEL_DEVICE:
        /* Check if this our existing ISA device */
        if (pdev == isa_bridge_pcidev ||
            (devnode && devnode == isa_bridge_devnode))
            isa_bridge_remove();
        return 0;
    }
    return 0;
}

static struct notifier_block isa_bridge_notifier = {
    .notifier_call = isa_bridge_notify
};

static int __init isa_bridge_init(void)
{
    bus_register_notifier(&pci_bus_type, &isa_bridge_notifier);
    return 0;
}
arch_initcall(isa_bridge_init);