// SPDX-License-Identifier: GPL-2.0-only
/*
 * Common pmac/prep/chrp pci routines. -- Cort
 */

#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/capability.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/memblock.h>
#include <linux/syscalls.h>
#include <linux/irq.h>
#include <linux/list.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/export.h>

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

#undef DEBUG

unsigned long isa_io_base     = 0;
unsigned long pci_dram_offset = 0;
int pcibios_assign_bus_offset = 1;
EXPORT_SYMBOL(isa_io_base);
EXPORT_SYMBOL(pci_dram_offset);

void pcibios_make_OF_bus_map(void);

static void fixup_cpc710_pci64(struct pci_dev* dev);
static u8* pci_to_OF_bus_map;

/* By default, we don't re-assign bus numbers. We do this only on
 * some pmacs
 */
static int pci_assign_all_buses;

static int pci_bus_count;

/* This will remain NULL for now, until isa-bridge.c is made common
 * to both 32-bit and 64-bit.
 */
struct pci_dev *isa_bridge_pcidev;
EXPORT_SYMBOL_GPL(isa_bridge_pcidev);

static void
fixup_cpc710_pci64(struct pci_dev* dev)
{
        /* Hide the PCI64 BARs from the kernel as their content doesn't
         * fit well in the resource management
         */
        dev->resource[0].start = dev->resource[0].end = 0;
        dev->resource[0].flags = 0;
        dev->resource[1].start = dev->resource[1].end = 0;
        dev->resource[1].flags = 0;
}
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_IBM,     PCI_DEVICE_ID_IBM_CPC710_PCI64, fixup_cpc710_pci64);

/*
 * Functions below are used on OpenFirmware machines.
 */
static void
make_one_node_map(struct device_node* node, u8 pci_bus)
{
        const int *bus_range;
        int len;

        if (pci_bus >= pci_bus_count)
                return;
        bus_range = of_get_property(node, "bus-range", &len);
        if (bus_range == NULL || len < 2 * sizeof(int)) {
                printk(KERN_WARNING "Can't get bus-range for %pOF, "
                       "assuming it starts at 0\n", node);
                pci_to_OF_bus_map[pci_bus] = 0;
        } else
                pci_to_OF_bus_map[pci_bus] = bus_range[0];

        for_each_child_of_node(node, node) {
                struct pci_dev* dev;
                const unsigned int *class_code, *reg;
        
                class_code = of_get_property(node, "class-code", NULL);
                if (!class_code || ((*class_code >> 8) != PCI_CLASS_BRIDGE_PCI &&
                        (*class_code >> 8) != PCI_CLASS_BRIDGE_CARDBUS))
                        continue;
                reg = of_get_property(node, "reg", NULL);
                if (!reg)
                        continue;
                dev = pci_get_domain_bus_and_slot(0, pci_bus,
                                                  ((reg[0] >> 8) & 0xff));
                if (!dev || !dev->subordinate) {
                        pci_dev_put(dev);
                        continue;
                }
                make_one_node_map(node, dev->subordinate->number);
                pci_dev_put(dev);
        }
}
        
void
pcibios_make_OF_bus_map(void)
{
        int i;
        struct pci_controller *hose, *tmp;
        struct property *map_prop;
        struct device_node *dn;

        pci_to_OF_bus_map = kmalloc(pci_bus_count, GFP_KERNEL);
        if (!pci_to_OF_bus_map) {
                printk(KERN_ERR "Can't allocate OF bus map !\n");
                return;
        }

        /* We fill the bus map with invalid values, that helps
         * debugging.
         */
        for (i=0; i<pci_bus_count; i++)
                pci_to_OF_bus_map[i] = 0xff;

        /* For each hose, we begin searching bridges */
        list_for_each_entry_safe(hose, tmp, &hose_list, list_node) {
                struct device_node* node = hose->dn;

                if (!node)
                        continue;
                make_one_node_map(node, hose->first_busno);
        }
        dn = of_find_node_by_path("/");
        map_prop = of_find_property(dn, "pci-OF-bus-map", NULL);
        if (map_prop) {
                BUG_ON(pci_bus_count > map_prop->length);
                memcpy(map_prop->value, pci_to_OF_bus_map, pci_bus_count);
        }
        of_node_put(dn);
#ifdef DEBUG
        printk("PCI->OF bus map:\n");
        for (i=0; i<pci_bus_count; i++) {
                if (pci_to_OF_bus_map[i] == 0xff)
                        continue;
                printk("%d -> %d\n", i, pci_to_OF_bus_map[i]);
        }
#endif
}


/*
 * Returns the PCI device matching a given OF node
 */
int pci_device_from_OF_node(struct device_node *node, u8 *bus, u8 *devfn)
{
        struct pci_dev *dev = NULL;
        const __be32 *reg;
        int size;

        /* Check if it might have a chance to be a PCI device */
        if (!pci_find_hose_for_OF_device(node))
                return -ENODEV;

        reg = of_get_property(node, "reg", &size);
        if (!reg || size < 5 * sizeof(u32))
                return -ENODEV;

        *bus = (be32_to_cpup(&reg[0]) >> 16) & 0xff;
        *devfn = (be32_to_cpup(&reg[0]) >> 8) & 0xff;

        /* Ok, here we need some tweak. If we have already renumbered
         * all busses, we can't rely on the OF bus number any more.
         * the pci_to_OF_bus_map is not enough as several PCI busses
         * may match the same OF bus number.
         */
        if (!pci_to_OF_bus_map)
                return 0;

        for_each_pci_dev(dev)
                if (pci_to_OF_bus_map[dev->bus->number] == *bus &&
                                dev->devfn == *devfn) {
                        *bus = dev->bus->number;
                        pci_dev_put(dev);
                        return 0;
                }

        return -ENODEV;
}
EXPORT_SYMBOL(pci_device_from_OF_node);

/* We create the "pci-OF-bus-map" property now so it appears in the
 * /proc device tree
 */
void __init
pci_create_OF_bus_map(void)
{
        struct property* of_prop;
        struct device_node *dn;

        of_prop = memblock_alloc(sizeof(struct property) + 256,
                                 SMP_CACHE_BYTES);
        if (!of_prop)
                panic("%s: Failed to allocate %zu bytes\n", __func__,
                      sizeof(struct property) + 256);
        dn = of_find_node_by_path("/");
        if (dn) {
                memset(of_prop, -1, sizeof(struct property) + 256);
                of_prop->name = "pci-OF-bus-map";
                of_prop->length = 256;
                of_prop->value = &of_prop[1];
                of_add_property(dn, of_prop);
                of_node_put(dn);
        }
}

void pcibios_setup_phb_io_space(struct pci_controller *hose)
{
        unsigned long io_offset;
        struct resource *res = &hose->io_resource;

        /* Fixup IO space offset */
        io_offset = pcibios_io_space_offset(hose);
        res->start += io_offset;
        res->end += io_offset;
}

static int __init pcibios_init(void)
{
        struct pci_controller *hose, *tmp;
        int next_busno = 0;

        printk(KERN_INFO "PCI: Probing PCI hardware\n");

        if (pci_has_flag(PCI_REASSIGN_ALL_BUS))
                pci_assign_all_buses = 1;

        /* Scan all of the recorded PCI controllers.  */
        list_for_each_entry_safe(hose, tmp, &hose_list, list_node) {
                if (pci_assign_all_buses)
                        hose->first_busno = next_busno;
                hose->last_busno = 0xff;
                pcibios_scan_phb(hose);
                pci_bus_add_devices(hose->bus);
                if (pci_assign_all_buses || next_busno <= hose->last_busno)
                        next_busno = hose->last_busno + pcibios_assign_bus_offset;
        }
        pci_bus_count = next_busno;

        /* OpenFirmware based machines need a map of OF bus
         * numbers vs. kernel bus numbers since we may have to
         * remap them.
         */
        if (pci_assign_all_buses)
                pcibios_make_OF_bus_map();

        /* Call common code to handle resource allocation */
        pcibios_resource_survey();

        /* Call machine dependent fixup */
        if (ppc_md.pcibios_fixup)
                ppc_md.pcibios_fixup();

        /* Call machine dependent post-init code */
        if (ppc_md.pcibios_after_init)
                ppc_md.pcibios_after_init();

        return 0;
}

subsys_initcall(pcibios_init);

static struct pci_controller*
pci_bus_to_hose(int bus)
{
        struct pci_controller *hose, *tmp;

        list_for_each_entry_safe(hose, tmp, &hose_list, list_node)
                if (bus >= hose->first_busno && bus <= hose->last_busno)
                        return hose;
        return NULL;
}

/* Provide information on locations of various I/O regions in physical
 * memory.  Do this on a per-card basis so that we choose the right
 * root bridge.
 * Note that the returned IO or memory base is a physical address
 */

SYSCALL_DEFINE3(pciconfig_iobase, long, which,
                unsigned long, bus, unsigned long, devfn)
{
        struct pci_controller* hose;
        long result = -EOPNOTSUPP;

        hose = pci_bus_to_hose(bus);
        if (!hose)
                return -ENODEV;

        switch (which) {
        case IOBASE_BRIDGE_NUMBER:
                return (long)hose->first_busno;
        case IOBASE_MEMORY:
                return (long)hose->mem_offset[0];
        case IOBASE_IO:
                return (long)hose->io_base_phys;
        case IOBASE_ISA_IO:
                return (long)isa_io_base;
        case IOBASE_ISA_MEM:
                return (long)isa_mem_base;
        }

        return result;
}