// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Routines for tracking a legacy ISA bridge
 *
 * Copyrigh 2007 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
 *
 * Some bits and pieces moved over from pci_64.c
 *
 * Copyrigh 2003 Anton Blanchard <anton@au.ibm.com>, IBM Corp.
 */

#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>
#include <asm/isa-bridge.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 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, pgprot_noncached(PAGE_KERNEL));
        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, pgprot_noncached(PAGE_KERNEL));
}


/**
 * isa_bridge_find_early - Find and map the ISA IO space early before
 *                         main PCI discovery. This is optionally called by
 *                         the arch code when adding PCI PHBs to get early
 *                         access to ISA IO ports
 */
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 %pOF\n", np);
}

/**
 * isa_bridge_find_early - Find and map the ISA IO space early before
 *                         main PCI discovery. This is optionally called by
 *                         the arch code when adding PCI PHBs to get early
 *                         access to ISA IO ports
 */
void __init isa_bridge_init_non_pci(struct device_node *np)
{
        const __be32 *ranges, *pbasep = NULL;
        int rlen, i, rs;
        u32 na, ns, pna;
        u64 cbase, pbase, size = 0;

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

        pna = of_n_addr_cells(np);
        if (of_property_read_u32(np, "#address-cells", &na) ||
            of_property_read_u32(np, "#size-cells", &ns)) {
                pr_warn("ISA: Non-PCI bridge %pOF is missing address format\n",
                        np);
                return;
        }

        /* Check it's a supported address format */
        if (na != 2 || ns != 1) {
                pr_warn("ISA: Non-PCI bridge %pOF has unsupported address format\n",
                        np);
                return;
        }
        rs = na + ns + pna;

        /* Grab the ranges property */
        ranges = of_get_property(np, "ranges", &rlen);
        if (ranges == NULL || rlen < rs) {
                pr_warn("ISA: Non-PCI bridge %pOF has absent or invalid ranges\n",
                        np);
                return;
        }

        /* Parse it. We are only looking for IO space */
        for (i = 0; (i + rs - 1) < rlen; i += rs) {
                if (be32_to_cpup(ranges + i) != 1)
                        continue;
                cbase = be32_to_cpup(ranges + i + 1);
                size = of_read_number(ranges + i + na + pna, ns);
                pbasep = ranges + i + na;
                break;
        }

        /* Got something ? */
        if (!size || !pbasep) {
                pr_warn("ISA: Non-PCI bridge %pOF has no usable IO range\n",
                        np);
                return;
        }

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

        /* Map pbase */
        pbase = of_translate_address(np, pbasep);
        if (pbase == OF_BAD_ADDR) {
                pr_warn("ISA: Non-PCI bridge %pOF failed to translate IO base\n",
                        np);
                return;
        }

        /* We need page alignment */
        if ((cbase & ~PAGE_MASK) || (pbase & ~PAGE_MASK)) {
                pr_warn("ISA: Non-PCI bridge %pOF has non aligned IO range\n",
                        np);
                return;
        }

        /* Got it */
        isa_bridge_devnode = np;

        /* Set the global ISA io base to indicate we have an ISA bridge
         * and map it
         */
        isa_io_base = ISA_IO_BASE;
        __ioremap_at(pbase, (void *)ISA_IO_BASE,
                     size, pgprot_noncached(PAGE_KERNEL));

        pr_debug("ISA: Non-PCI bridge is %pOF\n", np);
}

/**
 * isa_bridge_find_late - Find and map the ISA IO space upon discovery of
 *                        a new ISA bridge
 */
static void 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 %pOF on %s\n",
                 devnode, pci_name(pdev));
}

/**
 * isa_bridge_remove - Remove/unmap an ISA bridge
 */
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);
}

/**
 * isa_bridge_notify - Get notified of PCI devices addition/removal
 */
static int 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 && of_node_is_type(devnode, "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
};

/**
 * isa_bridge_init - register to be notified of ISA bridge addition/removal
 *
 */
static int __init isa_bridge_init(void)
{
        bus_register_notifier(&pci_bus_type, &isa_bridge_notifier);
        return 0;
}
arch_initcall(isa_bridge_init);