// SPDX-License-Identifier: GPL-2.0-only
/*
 * Helper routines to scan the device tree for PCI devices and busses
 *
 * Migrated out of PowerPC architecture pci_64.c file by Grant Likely
 * <grant.likely@secretlab.ca> so that these routines are available for
 * 32 bit also.
 *
 * Copyright (C) 2003 Anton Blanchard <anton@au.ibm.com>, IBM
 *   Rework, based on alpha PCI code.
 * Copyright (c) 2009 Secret Lab Technologies Ltd.
 */

#include <linux/pci.h>
#include <linux/export.h>
#include <asm/pci-bridge.h>
#include <asm/prom.h>

/**
 * get_int_prop - Decode a u32 from a device tree property
 */
static u32 get_int_prop(struct device_node *np, const char *name, u32 def)
{
        const __be32 *prop;
        int len;

        prop = of_get_property(np, name, &len);
        if (prop && len >= 4)
                return of_read_number(prop, 1);
        return def;
}

/**
 * pci_parse_of_flags - Parse the flags cell of a device tree PCI address
 * @addr0: value of 1st cell of a device tree PCI address.
 * @bridge: Set this flag if the address is from a bridge 'ranges' property
 */
unsigned int pci_parse_of_flags(u32 addr0, int bridge)
{
        unsigned int flags = 0;

        if (addr0 & 0x02000000) {
                flags = IORESOURCE_MEM | PCI_BASE_ADDRESS_SPACE_MEMORY;
                flags |= (addr0 >> 22) & PCI_BASE_ADDRESS_MEM_TYPE_64;
                if (flags & PCI_BASE_ADDRESS_MEM_TYPE_64)
                        flags |= IORESOURCE_MEM_64;
                flags |= (addr0 >> 28) & PCI_BASE_ADDRESS_MEM_TYPE_1M;
                if (addr0 & 0x40000000)
                        flags |= IORESOURCE_PREFETCH
                                 | PCI_BASE_ADDRESS_MEM_PREFETCH;
                /* Note: We don't know whether the ROM has been left enabled
                 * by the firmware or not. We mark it as disabled (ie, we do
                 * not set the IORESOURCE_ROM_ENABLE flag) for now rather than
                 * do a config space read, it will be force-enabled if needed
                 */
                if (!bridge && (addr0 & 0xff) == 0x30)
                        flags |= IORESOURCE_READONLY;
        } else if (addr0 & 0x01000000)
                flags = IORESOURCE_IO | PCI_BASE_ADDRESS_SPACE_IO;
        if (flags)
                flags |= IORESOURCE_SIZEALIGN;
        return flags;
}

/**
 * of_pci_parse_addrs - Parse PCI addresses assigned in the device tree node
 * @node: device tree node for the PCI device
 * @dev: pci_dev structure for the device
 *
 * This function parses the 'assigned-addresses' property of a PCI devices'
 * device tree node and writes them into the associated pci_dev structure.
 */
static void of_pci_parse_addrs(struct device_node *node, struct pci_dev *dev)
{
        u64 base, size;
        unsigned int flags;
        struct pci_bus_region region;
        struct resource *res;
        const __be32 *addrs;
        u32 i;
        int proplen;
        bool mark_unset = false;

        addrs = of_get_property(node, "assigned-addresses", &proplen);
        if (!addrs || !proplen) {
                addrs = of_get_property(node, "reg", &proplen);
                if (!addrs || !proplen)
                        return;
                mark_unset = true;
        }

        pr_debug("    parse addresses (%d bytes) @ %p\n", proplen, addrs);
        for (; proplen >= 20; proplen -= 20, addrs += 5) {
                flags = pci_parse_of_flags(of_read_number(addrs, 1), 0);
                if (!flags)
                        continue;
                base = of_read_number(&addrs[1], 2);
                size = of_read_number(&addrs[3], 2);
                if (!size)
                        continue;
                i = of_read_number(addrs, 1) & 0xff;
                pr_debug("  base: %llx, size: %llx, i: %x\n",
                         (unsigned long long)base,
                         (unsigned long long)size, i);

                if (PCI_BASE_ADDRESS_0 <= i && i <= PCI_BASE_ADDRESS_5) {
                        res = &dev->resource[(i - PCI_BASE_ADDRESS_0) >> 2];
                } else if (i == dev->rom_base_reg) {
                        res = &dev->resource[PCI_ROM_RESOURCE];
                        flags |= IORESOURCE_READONLY;
                } else {
                        printk(KERN_ERR "PCI: bad cfg reg num 0x%x\n", i);
                        continue;
                }
                res->flags = flags;
                if (mark_unset)
                        res->flags |= IORESOURCE_UNSET;
                res->name = pci_name(dev);
                region.start = base;
                region.end = base + size - 1;
                pcibios_bus_to_resource(dev->bus, res, &region);
        }
}

/**
 * of_create_pci_dev - Given a device tree node on a pci bus, create a pci_dev
 * @node: device tree node pointer
 * @bus: bus the device is sitting on
 * @devfn: PCI function number, extracted from device tree by caller.
 */
struct pci_dev *of_create_pci_dev(struct device_node *node,
                                 struct pci_bus *bus, int devfn)
{
        struct pci_dev *dev;

        dev = pci_alloc_dev(bus);
        if (!dev)
                return NULL;

        pr_debug("    create device, devfn: %x, type: %s\n", devfn,
                 of_node_get_device_type(node));

        dev->dev.of_node = of_node_get(node);
        dev->dev.parent = bus->bridge;
        dev->dev.bus = &pci_bus_type;
        dev->devfn = devfn;
        dev->multifunction = 0;         /* maybe a lie? */
        dev->needs_freset = 0;          /* pcie fundamental reset required */
        set_pcie_port_type(dev);

        pci_dev_assign_slot(dev);
        dev->vendor = get_int_prop(node, "vendor-id", 0xffff);
        dev->device = get_int_prop(node, "device-id", 0xffff);
        dev->subsystem_vendor = get_int_prop(node, "subsystem-vendor-id", 0);
        dev->subsystem_device = get_int_prop(node, "subsystem-id", 0);

        dev->cfg_size = pci_cfg_space_size(dev);

        dev_set_name(&dev->dev, "%04x:%02x:%02x.%d", pci_domain_nr(bus),
                dev->bus->number, PCI_SLOT(devfn), PCI_FUNC(devfn));
        dev->class = get_int_prop(node, "class-code", 0);
        dev->revision = get_int_prop(node, "revision-id", 0);

        pr_debug("    class: 0x%x\n", dev->class);
        pr_debug("    revision: 0x%x\n", dev->revision);

        dev->current_state = PCI_UNKNOWN;       /* unknown power state */
        dev->error_state = pci_channel_io_normal;
        dev->dma_mask = 0xffffffff;

        /* Early fixups, before probing the BARs */
        pci_fixup_device(pci_fixup_early, dev);

        if (of_node_is_type(node, "pci") || of_node_is_type(node, "pciex")) {
                /* a PCI-PCI bridge */
                dev->hdr_type = PCI_HEADER_TYPE_BRIDGE;
                dev->rom_base_reg = PCI_ROM_ADDRESS1;
                set_pcie_hotplug_bridge(dev);
        } else if (of_node_is_type(node, "cardbus")) {
                dev->hdr_type = PCI_HEADER_TYPE_CARDBUS;
        } else {
                dev->hdr_type = PCI_HEADER_TYPE_NORMAL;
                dev->rom_base_reg = PCI_ROM_ADDRESS;
                /* Maybe do a default OF mapping here */
                dev->irq = 0;
        }

        of_pci_parse_addrs(node, dev);

        pr_debug("    adding to system ...\n");

        pci_device_add(dev, bus);

        return dev;
}
EXPORT_SYMBOL(of_create_pci_dev);

/**
 * of_scan_pci_bridge - Set up a PCI bridge and scan for child nodes
 * @dev: pci_dev structure for the bridge
 *
 * of_scan_bus() calls this routine for each PCI bridge that it finds, and
 * this routine in turn call of_scan_bus() recusively to scan for more child
 * devices.
 */
void of_scan_pci_bridge(struct pci_dev *dev)
{
        struct device_node *node = dev->dev.of_node;
        struct pci_bus *bus;
        struct pci_controller *phb;
        const __be32 *busrange, *ranges;
        int len, i, mode;
        struct pci_bus_region region;
        struct resource *res;
        unsigned int flags;
        u64 size;

        pr_debug("of_scan_pci_bridge(%pOF)\n", node);

        /* parse bus-range property */
        busrange = of_get_property(node, "bus-range", &len);
        if (busrange == NULL || len != 8) {
                printk(KERN_DEBUG "Can't get bus-range for PCI-PCI bridge %pOF\n",
                       node);
                return;
        }
        ranges = of_get_property(node, "ranges", &len);
        if (ranges == NULL) {
                printk(KERN_DEBUG "Can't get ranges for PCI-PCI bridge %pOF\n",
                       node);
                return;
        }

        bus = pci_find_bus(pci_domain_nr(dev->bus),
                           of_read_number(busrange, 1));
        if (!bus) {
                bus = pci_add_new_bus(dev->bus, dev,
                                      of_read_number(busrange, 1));
                if (!bus) {
                        printk(KERN_ERR "Failed to create pci bus for %pOF\n",
                               node);
                        return;
                }
        }

        bus->primary = dev->bus->number;
        pci_bus_insert_busn_res(bus, of_read_number(busrange, 1),
                                of_read_number(busrange+1, 1));
        bus->bridge_ctl = 0;

        /* parse ranges property */
        /* PCI #address-cells == 3 and #size-cells == 2 always */
        res = &dev->resource[PCI_BRIDGE_RESOURCES];
        for (i = 0; i < PCI_NUM_RESOURCES - PCI_BRIDGE_RESOURCES; ++i) {
                res->flags = 0;
                bus->resource[i] = res;
                ++res;
        }
        i = 1;
        for (; len >= 32; len -= 32, ranges += 8) {
                flags = pci_parse_of_flags(of_read_number(ranges, 1), 1);
                size = of_read_number(&ranges[6], 2);
                if (flags == 0 || size == 0)
                        continue;
                if (flags & IORESOURCE_IO) {
                        res = bus->resource[0];
                        if (res->flags) {
                                printk(KERN_ERR "PCI: ignoring extra I/O range"
                                       " for bridge %pOF\n", node);
                                continue;
                        }
                } else {
                        if (i >= PCI_NUM_RESOURCES - PCI_BRIDGE_RESOURCES) {
                                printk(KERN_ERR "PCI: too many memory ranges"
                                       " for bridge %pOF\n", node);
                                continue;
                        }
                        res = bus->resource[i];
                        ++i;
                }
                res->flags = flags;
                region.start = of_read_number(&ranges[1], 2);
                region.end = region.start + size - 1;
                pcibios_bus_to_resource(dev->bus, res, &region);
        }
        sprintf(bus->name, "PCI Bus %04x:%02x", pci_domain_nr(bus),
                bus->number);
        pr_debug("    bus name: %s\n", bus->name);

        phb = pci_bus_to_host(bus);

        mode = PCI_PROBE_NORMAL;
        if (phb->controller_ops.probe_mode)
                mode = phb->controller_ops.probe_mode(bus);
        pr_debug("    probe mode: %d\n", mode);

        if (mode == PCI_PROBE_DEVTREE)
                of_scan_bus(node, bus);
        else if (mode == PCI_PROBE_NORMAL)
                pci_scan_child_bus(bus);
}
EXPORT_SYMBOL(of_scan_pci_bridge);

static struct pci_dev *of_scan_pci_dev(struct pci_bus *bus,
                            struct device_node *dn)
{
        struct pci_dev *dev = NULL;
        const __be32 *reg;
        int reglen, devfn;
#ifdef CONFIG_EEH
        struct eeh_dev *edev = pdn_to_eeh_dev(PCI_DN(dn));
#endif

        pr_debug("  * %pOF\n", dn);
        if (!of_device_is_available(dn))
                return NULL;

        reg = of_get_property(dn, "reg", &reglen);
        if (reg == NULL || reglen < 20)
                return NULL;
        devfn = (of_read_number(reg, 1) >> 8) & 0xff;

        /* Check if the PCI device is already there */
        dev = pci_get_slot(bus, devfn);
        if (dev) {
                pci_dev_put(dev);
                return dev;
        }

        /* Device removed permanently ? */
#ifdef CONFIG_EEH
        if (edev && (edev->mode & EEH_DEV_REMOVED))
                return NULL;
#endif

        /* create a new pci_dev for this device */
        dev = of_create_pci_dev(dn, bus, devfn);
        if (!dev)
                return NULL;

        pr_debug("  dev header type: %x\n", dev->hdr_type);
        return dev;
}

/**
 * __of_scan_bus - given a PCI bus node, setup bus and scan for child devices
 * @node: device tree node for the PCI bus
 * @bus: pci_bus structure for the PCI bus
 * @rescan_existing: Flag indicating bus has already been set up
 */
static void __of_scan_bus(struct device_node *node, struct pci_bus *bus,
                          int rescan_existing)
{
        struct device_node *child;
        struct pci_dev *dev;

        pr_debug("of_scan_bus(%pOF) bus no %d...\n",
                 node, bus->number);

        /* Scan direct children */
        for_each_child_of_node(node, child) {
                dev = of_scan_pci_dev(bus, child);
                if (!dev)
                        continue;
                pr_debug("    dev header type: %x\n", dev->hdr_type);
        }

        /* Apply all fixups necessary. We don't fixup the bus "self"
         * for an existing bridge that is being rescanned
         */
        if (!rescan_existing)
                pcibios_setup_bus_self(bus);
        pcibios_setup_bus_devices(bus);

        /* Now scan child busses */
        for_each_pci_bridge(dev, bus)
                of_scan_pci_bridge(dev);
}

/**
 * of_scan_bus - given a PCI bus node, setup bus and scan for child devices
 * @node: device tree node for the PCI bus
 * @bus: pci_bus structure for the PCI bus
 */
void of_scan_bus(struct device_node *node, struct pci_bus *bus)
{
        __of_scan_bus(node, bus, 0);
}
EXPORT_SYMBOL_GPL(of_scan_bus);

/**
 * of_rescan_bus - given a PCI bus node, scan for child devices
 * @node: device tree node for the PCI bus
 * @bus: pci_bus structure for the PCI bus
 *
 * Same as of_scan_bus, but for a pci_bus structure that has already been
 * setup.
 */
void of_rescan_bus(struct device_node *node, struct pci_bus *bus)
{
        __of_scan_bus(node, bus, 1);
}
EXPORT_SYMBOL_GPL(of_rescan_bus);