// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/arch/arm/kernel/bios32.c
 *
 *  PCI bios-type initialisation for PCI machines
 *
 *  Bits taken from various places.
 */
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/io.h>

#include <asm/mach-types.h>
#include <asm/mach/map.h>
#include <asm/mach/pci.h>

static int debug_pci;

/*
 * We can't use pci_get_device() here since we are
 * called from interrupt context.
 */
static void pcibios_bus_report_status(struct pci_bus *bus, u_int status_mask, int warn)
{
        struct pci_dev *dev;

        list_for_each_entry(dev, &bus->devices, bus_list) {
                u16 status;

                /*
                 * ignore host bridge - we handle
                 * that separately
                 */
                if (dev->bus->number == 0 && dev->devfn == 0)
                        continue;

                pci_read_config_word(dev, PCI_STATUS, &status);
                if (status == 0xffff)
                        continue;

                if ((status & status_mask) == 0)
                        continue;

                /* clear the status errors */
                pci_write_config_word(dev, PCI_STATUS, status & status_mask);

                if (warn)
                        printk("(%s: %04X) ", pci_name(dev), status);
        }

        list_for_each_entry(dev, &bus->devices, bus_list)
                if (dev->subordinate)
                        pcibios_bus_report_status(dev->subordinate, status_mask, warn);
}

void pcibios_report_status(u_int status_mask, int warn)
{
        struct pci_bus *bus;

        list_for_each_entry(bus, &pci_root_buses, node)
                pcibios_bus_report_status(bus, status_mask, warn);
}

/*
 * We don't use this to fix the device, but initialisation of it.
 * It's not the correct use for this, but it works.
 * Note that the arbiter/ISA bridge appears to be buggy, specifically in
 * the following area:
 * 1. park on CPU
 * 2. ISA bridge ping-pong
 * 3. ISA bridge master handling of target RETRY
 *
 * Bug 3 is responsible for the sound DMA grinding to a halt.  We now
 * live with bug 2.
 */
static void pci_fixup_83c553(struct pci_dev *dev)
{
        /*
         * Set memory region to start at address 0, and enable IO
         */
        pci_write_config_dword(dev, PCI_BASE_ADDRESS_0, PCI_BASE_ADDRESS_SPACE_MEMORY);
        pci_write_config_word(dev, PCI_COMMAND, PCI_COMMAND_IO);

        dev->resource[0].end -= dev->resource[0].start;
        dev->resource[0].start = 0;

        /*
         * All memory requests from ISA to be channelled to PCI
         */
        pci_write_config_byte(dev, 0x48, 0xff);

        /*
         * Enable ping-pong on bus master to ISA bridge transactions.
         * This improves the sound DMA substantially.  The fixed
         * priority arbiter also helps (see below).
         */
        pci_write_config_byte(dev, 0x42, 0x01);

        /*
         * Enable PCI retry
         */
        pci_write_config_byte(dev, 0x40, 0x22);

        /*
         * We used to set the arbiter to "park on last master" (bit
         * 1 set), but unfortunately the CyberPro does not park the
         * bus.  We must therefore park on CPU.  Unfortunately, this
         * may trigger yet another bug in the 553.
         */
        pci_write_config_byte(dev, 0x83, 0x02);

        /*
         * Make the ISA DMA request lowest priority, and disable
         * rotating priorities completely.
         */
        pci_write_config_byte(dev, 0x80, 0x11);
        pci_write_config_byte(dev, 0x81, 0x00);

        /*
         * Route INTA input to IRQ 11, and set IRQ11 to be level
         * sensitive.
         */
        pci_write_config_word(dev, 0x44, 0xb000);
        outb(0x08, 0x4d1);
}
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_WINBOND, PCI_DEVICE_ID_WINBOND_83C553, pci_fixup_83c553);

static void pci_fixup_unassign(struct pci_dev *dev)
{
        dev->resource[0].end -= dev->resource[0].start;
        dev->resource[0].start = 0;
}
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_WINBOND2, PCI_DEVICE_ID_WINBOND2_89C940F, pci_fixup_unassign);

/*
 * Prevent the PCI layer from seeing the resources allocated to this device
 * if it is the host bridge by marking it as such.  These resources are of
 * no consequence to the PCI layer (they are handled elsewhere).
 */
static void pci_fixup_dec21285(struct pci_dev *dev)
{
        int i;

        if (dev->devfn == 0) {
                dev->class &= 0xff;
                dev->class |= PCI_CLASS_BRIDGE_HOST << 8;
                for (i = 0; i < PCI_NUM_RESOURCES; i++) {
                        dev->resource[i].start = 0;
                        dev->resource[i].end   = 0;
                        dev->resource[i].flags = 0;
                }
        }
}
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_DEC, PCI_DEVICE_ID_DEC_21285, pci_fixup_dec21285);

/*
 * PCI IDE controllers use non-standard I/O port decoding, respect it.
 */
static void pci_fixup_ide_bases(struct pci_dev *dev)
{
        struct resource *r;
        int i;

        if ((dev->class >> 8) != PCI_CLASS_STORAGE_IDE)
                return;

        for (i = 0; i < PCI_NUM_RESOURCES; i++) {
                r = dev->resource + i;
                if ((r->start & ~0x80) == 0x374) {
                        r->start |= 2;
                        r->end = r->start;
                }
        }
}
DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, pci_fixup_ide_bases);

/*
 * Put the DEC21142 to sleep
 */
static void pci_fixup_dec21142(struct pci_dev *dev)
{
        pci_write_config_dword(dev, 0x40, 0x80000000);
}
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_DEC, PCI_DEVICE_ID_DEC_21142, pci_fixup_dec21142);

/*
 * The CY82C693 needs some rather major fixups to ensure that it does
 * the right thing.  Idea from the Alpha people, with a few additions.
 *
 * We ensure that the IDE base registers are set to 1f0/3f4 for the
 * primary bus, and 170/374 for the secondary bus.  Also, hide them
 * from the PCI subsystem view as well so we won't try to perform
 * our own auto-configuration on them.
 *
 * In addition, we ensure that the PCI IDE interrupts are routed to
 * IRQ 14 and IRQ 15 respectively.
 *
 * The above gets us to a point where the IDE on this device is
 * functional.  However, The CY82C693U _does not work_ in bus
 * master mode without locking the PCI bus solid.
 */
static void pci_fixup_cy82c693(struct pci_dev *dev)
{
        if ((dev->class >> 8) == PCI_CLASS_STORAGE_IDE) {
                u32 base0, base1;

                if (dev->class & 0x80) {        /* primary */
                        base0 = 0x1f0;
                        base1 = 0x3f4;
                } else {                        /* secondary */
                        base0 = 0x170;
                        base1 = 0x374;
                }

                pci_write_config_dword(dev, PCI_BASE_ADDRESS_0,
                                       base0 | PCI_BASE_ADDRESS_SPACE_IO);
                pci_write_config_dword(dev, PCI_BASE_ADDRESS_1,
                                       base1 | PCI_BASE_ADDRESS_SPACE_IO);

                dev->resource[0].start = 0;
                dev->resource[0].end   = 0;
                dev->resource[0].flags = 0;

                dev->resource[1].start = 0;
                dev->resource[1].end   = 0;
                dev->resource[1].flags = 0;
        } else if (PCI_FUNC(dev->devfn) == 0) {
                /*
                 * Setup IDE IRQ routing.
                 */
                pci_write_config_byte(dev, 0x4b, 14);
                pci_write_config_byte(dev, 0x4c, 15);

                /*
                 * Disable FREQACK handshake, enable USB.
                 */
                pci_write_config_byte(dev, 0x4d, 0x41);

                /*
                 * Enable PCI retry, and PCI post-write buffer.
                 */
                pci_write_config_byte(dev, 0x44, 0x17);

                /*
                 * Enable ISA master and DMA post write buffering.
                 */
                pci_write_config_byte(dev, 0x45, 0x03);
        }
}
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_CONTAQ, PCI_DEVICE_ID_CONTAQ_82C693, pci_fixup_cy82c693);

/*
 * If the bus contains any of these devices, then we must not turn on
 * parity checking of any kind.  Currently this is CyberPro 20x0 only.
 */
static inline int pdev_bad_for_parity(struct pci_dev *dev)
{
        return ((dev->vendor == PCI_VENDOR_ID_INTERG &&
                 (dev->device == PCI_DEVICE_ID_INTERG_2000 ||
                  dev->device == PCI_DEVICE_ID_INTERG_2010)) ||
                (dev->vendor == PCI_VENDOR_ID_ITE &&
                 dev->device == PCI_DEVICE_ID_ITE_8152));

}

/*
 * pcibios_fixup_bus - Called after each bus is probed,
 * but before its children are examined.
 */
void pcibios_fixup_bus(struct pci_bus *bus)
{
        struct pci_dev *dev;
        u16 features = PCI_COMMAND_SERR | PCI_COMMAND_PARITY | PCI_COMMAND_FAST_BACK;

        /*
         * Walk the devices on this bus, working out what we can
         * and can't support.
         */
        list_for_each_entry(dev, &bus->devices, bus_list) {
                u16 status;

                pci_read_config_word(dev, PCI_STATUS, &status);

                /*
                 * If any device on this bus does not support fast back
                 * to back transfers, then the bus as a whole is not able
                 * to support them.  Having fast back to back transfers
                 * on saves us one PCI cycle per transaction.
                 */
                if (!(status & PCI_STATUS_FAST_BACK))
                        features &= ~PCI_COMMAND_FAST_BACK;

                if (pdev_bad_for_parity(dev))
                        features &= ~(PCI_COMMAND_SERR | PCI_COMMAND_PARITY);

                switch (dev->class >> 8) {
                case PCI_CLASS_BRIDGE_PCI:
                        pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &status);
                        status |= PCI_BRIDGE_CTL_PARITY|PCI_BRIDGE_CTL_MASTER_ABORT;
                        status &= ~(PCI_BRIDGE_CTL_BUS_RESET|PCI_BRIDGE_CTL_FAST_BACK);
                        pci_write_config_word(dev, PCI_BRIDGE_CONTROL, status);
                        break;

                case PCI_CLASS_BRIDGE_CARDBUS:
                        pci_read_config_word(dev, PCI_CB_BRIDGE_CONTROL, &status);
                        status |= PCI_CB_BRIDGE_CTL_PARITY|PCI_CB_BRIDGE_CTL_MASTER_ABORT;
                        pci_write_config_word(dev, PCI_CB_BRIDGE_CONTROL, status);
                        break;
                }
        }

        /*
         * Now walk the devices again, this time setting them up.
         */
        list_for_each_entry(dev, &bus->devices, bus_list) {
                u16 cmd;

                pci_read_config_word(dev, PCI_COMMAND, &cmd);
                cmd |= features;
                pci_write_config_word(dev, PCI_COMMAND, cmd);

                pci_write_config_byte(dev, PCI_CACHE_LINE_SIZE,
                                      L1_CACHE_BYTES >> 2);
        }

        /*
         * Propagate the flags to the PCI bridge.
         */
        if (bus->self && bus->self->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
                if (features & PCI_COMMAND_FAST_BACK)
                        bus->bridge_ctl |= PCI_BRIDGE_CTL_FAST_BACK;
                if (features & PCI_COMMAND_PARITY)
                        bus->bridge_ctl |= PCI_BRIDGE_CTL_PARITY;
        }

        /*
         * Report what we did for this bus
         */
        pr_info("PCI: bus%d: Fast back to back transfers %sabled\n",
                bus->number, (features & PCI_COMMAND_FAST_BACK) ? "en" : "dis");
}
EXPORT_SYMBOL(pcibios_fixup_bus);

/*
 * Swizzle the device pin each time we cross a bridge.  If a platform does
 * not provide a swizzle function, we perform the standard PCI swizzling.
 *
 * The default swizzling walks up the bus tree one level at a time, applying
 * the standard swizzle function at each step, stopping when it finds the PCI
 * root bus.  This will return the slot number of the bridge device on the
 * root bus and the interrupt pin on that device which should correspond
 * with the downstream device interrupt.
 *
 * Platforms may override this, in which case the slot and pin returned
 * depend entirely on the platform code.  However, please note that the
 * PCI standard swizzle is implemented on plug-in cards and Cardbus based
 * PCI extenders, so it can not be ignored.
 */
static u8 pcibios_swizzle(struct pci_dev *dev, u8 *pin)
{
        struct pci_sys_data *sys = dev->sysdata;
        int slot, oldpin = *pin;

        if (sys->swizzle)
                slot = sys->swizzle(dev, pin);
        else
                slot = pci_common_swizzle(dev, pin);

        if (debug_pci)
                printk("PCI: %s swizzling pin %d => pin %d slot %d\n",
                        pci_name(dev), oldpin, *pin, slot);

        return slot;
}

/*
 * Map a slot/pin to an IRQ.
 */
static int pcibios_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
{
        struct pci_sys_data *sys = dev->sysdata;
        int irq = -1;

        if (sys->map_irq)
                irq = sys->map_irq(dev, slot, pin);

        if (debug_pci)
                printk("PCI: %s mapping slot %d pin %d => irq %d\n",
                        pci_name(dev), slot, pin, irq);

        return irq;
}

static int pcibios_init_resource(int busnr, struct pci_sys_data *sys)
{
        int ret;
        struct resource_entry *window;

        if (list_empty(&sys->resources)) {
                pci_add_resource_offset(&sys->resources,
                         &iomem_resource, sys->mem_offset);
        }

        resource_list_for_each_entry(window, &sys->resources)
                if (resource_type(window->res) == IORESOURCE_IO)
                        return 0;

        sys->io_res.start = (busnr * SZ_64K) ?  : pcibios_min_io;
        sys->io_res.end = (busnr + 1) * SZ_64K - 1;
        sys->io_res.flags = IORESOURCE_IO;
        sys->io_res.name = sys->io_res_name;
        sprintf(sys->io_res_name, "PCI%d I/O", busnr);

        ret = request_resource(&ioport_resource, &sys->io_res);
        if (ret) {
                pr_err("PCI: unable to allocate I/O port region (%d)\n", ret);
                return ret;
        }
        pci_add_resource_offset(&sys->resources, &sys->io_res,
                                sys->io_offset);

        return 0;
}

static void pcibios_init_hw(struct device *parent, struct hw_pci *hw,
                            struct list_head *head)
{
        struct pci_sys_data *sys = NULL;
        int ret;
        int nr, busnr;

        for (nr = busnr = 0; nr < hw->nr_controllers; nr++) {
                struct pci_host_bridge *bridge;

                bridge = pci_alloc_host_bridge(sizeof(struct pci_sys_data));
                if (WARN(!bridge, "PCI: unable to allocate bridge!"))
                        break;

                sys = pci_host_bridge_priv(bridge);

                sys->busnr   = busnr;
                sys->swizzle = hw->swizzle;
                sys->map_irq = hw->map_irq;
                INIT_LIST_HEAD(&sys->resources);

                if (hw->private_data)
                        sys->private_data = hw->private_data[nr];

                ret = hw->setup(nr, sys);

                if (ret > 0) {

                        ret = pcibios_init_resource(nr, sys);
                        if (ret)  {
                                pci_free_host_bridge(bridge);
                                break;
                        }

                        bridge->map_irq = pcibios_map_irq;
                        bridge->swizzle_irq = pcibios_swizzle;

                        if (hw->scan)
                                ret = hw->scan(nr, bridge);
                        else {
                                list_splice_init(&sys->resources,
                                                 &bridge->windows);
                                bridge->dev.parent = parent;
                                bridge->sysdata = sys;
                                bridge->busnr = sys->busnr;
                                bridge->ops = hw->ops;

                                ret = pci_scan_root_bus_bridge(bridge);
                        }

                        if (WARN(ret < 0, "PCI: unable to scan bus!")) {
                                pci_free_host_bridge(bridge);
                                break;
                        }

                        sys->bus = bridge->bus;

                        busnr = sys->bus->busn_res.end + 1;

                        list_add(&sys->node, head);
                } else {
                        pci_free_host_bridge(bridge);
                        if (ret < 0)
                                break;
                }
        }
}

void pci_common_init_dev(struct device *parent, struct hw_pci *hw)
{
        struct pci_sys_data *sys;
        LIST_HEAD(head);

        pci_add_flags(PCI_REASSIGN_ALL_BUS);
        if (hw->preinit)
                hw->preinit();
        pcibios_init_hw(parent, hw, &head);
        if (hw->postinit)
                hw->postinit();

        list_for_each_entry(sys, &head, node) {
                struct pci_bus *bus = sys->bus;

                /*
                 * We insert PCI resources into the iomem_resource and
                 * ioport_resource trees in either pci_bus_claim_resources()
                 * or pci_bus_assign_resources().
                 */
                if (pci_has_flag(PCI_PROBE_ONLY)) {
                        pci_bus_claim_resources(bus);
                } else {
                        struct pci_bus *child;

                        pci_bus_size_bridges(bus);
                        pci_bus_assign_resources(bus);

                        list_for_each_entry(child, &bus->children, node)
                                pcie_bus_configure_settings(child);
                }

                pci_bus_add_devices(bus);
        }
}

#ifndef CONFIG_PCI_HOST_ITE8152
void pcibios_set_master(struct pci_dev *dev)
{
        /* No special bus mastering setup handling */
}
#endif

char * __init pcibios_setup(char *str)
{
        if (!strcmp(str, "debug")) {
                debug_pci = 1;
                return NULL;
        }
        return str;
}

/*
 * From arch/i386/kernel/pci-i386.c:
 *
 * We need to avoid collisions with `mirrored' VGA ports
 * and other strange ISA hardware, so we always want the
 * addresses to be allocated in the 0x000-0x0ff region
 * modulo 0x400.
 *
 * Why? Because some silly external IO cards only decode
 * the low 10 bits of the IO address. The 0x00-0xff region
 * is reserved for motherboard devices that decode all 16
 * bits, so it's ok to allocate at, say, 0x2800-0x28ff,
 * but we want to try to avoid allocating at 0x2900-0x2bff
 * which might be mirrored at 0x0100-0x03ff..
 */
resource_size_t pcibios_align_resource(void *data, const struct resource *res,
                                resource_size_t size, resource_size_t align)
{
        struct pci_dev *dev = data;
        resource_size_t start = res->start;
        struct pci_host_bridge *host_bridge;

        if (res->flags & IORESOURCE_IO && start & 0x300)
                start = (start + 0x3ff) & ~0x3ff;

        start = (start + align - 1) & ~(align - 1);

        host_bridge = pci_find_host_bridge(dev->bus);

        if (host_bridge->align_resource)
                return host_bridge->align_resource(dev, res,
                                start, size, align);

        return start;
}

void __init pci_map_io_early(unsigned long pfn)
{
        struct map_desc pci_io_desc = {
                .virtual        = PCI_IO_VIRT_BASE,
                .type           = MT_DEVICE,
                .length         = SZ_64K,
        };

        pci_io_desc.pfn = pfn;
        iotable_init(&pci_io_desc, 1);
}