// SPDX-License-Identifier: GPL-2.0-only
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>

#include <asm/addrspace.h>
#include <asm/paccess.h>
#include <asm/gio_device.h>
#include <asm/sgi/gio.h>
#include <asm/sgi/hpc3.h>
#include <asm/sgi/mc.h>
#include <asm/sgi/ip22.h>

static const struct bus_type gio_bus_type;

static struct {
        const char *name;
        __u8       id;
} gio_name_table[] = {
        { .name = "SGI Impact", .id = 0x10 },
        { .name = "Phobos G160", .id = 0x35 },
        { .name = "Phobos G130", .id = 0x36 },
        { .name = "Phobos G100", .id = 0x37 },
        { .name = "Set Engineering GFE", .id = 0x38 },
        /* fake IDs */
        { .name = "SGI Newport", .id = 0x7e },
        { .name = "SGI GR2/GR3", .id = 0x7f },
};

static void gio_bus_release(struct device *dev)
{
        kfree(dev);
}

static struct device gio_bus = {
        .init_name = "gio",
        .release = &gio_bus_release,
};

/**
 * gio_match_device - Tell if an of_device structure has a matching
 * gio_match structure
 * @ids: array of of device match structures to search in
 * @dev: the of device structure to match against
 *
 * Used by a driver to check whether an of_device present in the
 * system is in its list of supported devices.
 */
static const struct gio_device_id *
gio_match_device(const struct gio_device_id *match,
                 const struct gio_device *dev)
{
        const struct gio_device_id *ids;

        for (ids = match; ids->id != 0xff; ids++)
                if (ids->id == dev->id.id)
                        return ids;

        return NULL;
}

struct gio_device *gio_dev_get(struct gio_device *dev)
{
        struct device *tmp;

        if (!dev)
                return NULL;
        tmp = get_device(&dev->dev);
        if (tmp)
                return to_gio_device(tmp);
        else
                return NULL;
}
EXPORT_SYMBOL_GPL(gio_dev_get);

void gio_dev_put(struct gio_device *dev)
{
        if (dev)
                put_device(&dev->dev);
}
EXPORT_SYMBOL_GPL(gio_dev_put);

/**
 * gio_release_dev - free an gio device structure when all users of it are finished.
 * @dev: device that's been disconnected
 *
 * Will be called only by the device core when all users of this gio device are
 * done.
 */
void gio_release_dev(struct device *dev)
{
        struct gio_device *giodev;

        giodev = to_gio_device(dev);
        kfree(giodev);
}
EXPORT_SYMBOL_GPL(gio_release_dev);

int gio_device_register(struct gio_device *giodev)
{
        giodev->dev.bus = &gio_bus_type;
        giodev->dev.parent = &gio_bus;
        return device_register(&giodev->dev);
}
EXPORT_SYMBOL_GPL(gio_device_register);

void gio_device_unregister(struct gio_device *giodev)
{
        device_unregister(&giodev->dev);
}
EXPORT_SYMBOL_GPL(gio_device_unregister);

static int gio_bus_match(struct device *dev, const struct device_driver *drv)
{
        struct gio_device *gio_dev = to_gio_device(dev);
        struct gio_driver *gio_drv = to_gio_driver(drv);

        return gio_match_device(gio_drv->id_table, gio_dev) != NULL;
}

static int gio_device_probe(struct device *dev)
{
        int error = -ENODEV;
        struct gio_driver *drv;
        struct gio_device *gio_dev;
        const struct gio_device_id *match;

        drv = to_gio_driver(dev->driver);
        gio_dev = to_gio_device(dev);

        if (!drv->probe)
                return error;

        gio_dev_get(gio_dev);

        match = gio_match_device(drv->id_table, gio_dev);
        if (match)
                error = drv->probe(gio_dev, match);
        if (error)
                gio_dev_put(gio_dev);

        return error;
}

static void gio_device_remove(struct device *dev)
{
        struct gio_device *gio_dev = to_gio_device(dev);
        struct gio_driver *drv = to_gio_driver(dev->driver);

        if (drv->remove)
                drv->remove(gio_dev);
}

static void gio_device_shutdown(struct device *dev)
{
        struct gio_device *gio_dev = to_gio_device(dev);
        struct gio_driver *drv = to_gio_driver(dev->driver);

        if (dev->driver && drv->shutdown)
                drv->shutdown(gio_dev);
}

static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
                             char *buf)
{
        struct gio_device *gio_dev = to_gio_device(dev);

        return sysfs_emit(buf, "gio:%x\n", gio_dev->id.id);
}
static DEVICE_ATTR_RO(modalias);

static ssize_t name_show(struct device *dev,
                         struct device_attribute *attr, char *buf)
{
        struct gio_device *giodev;

        giodev = to_gio_device(dev);
        return sysfs_emit(buf, "%s\n", giodev->name);
}
static DEVICE_ATTR_RO(name);

static ssize_t id_show(struct device *dev,
                       struct device_attribute *attr, char *buf)
{
        struct gio_device *giodev;

        giodev = to_gio_device(dev);
        return sysfs_emit(buf, "%x\n", giodev->id.id);
}
static DEVICE_ATTR_RO(id);

static struct attribute *gio_dev_attrs[] = {
        &dev_attr_modalias.attr,
        &dev_attr_name.attr,
        &dev_attr_id.attr,
        NULL,
};
ATTRIBUTE_GROUPS(gio_dev);

static int gio_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
{
        const struct gio_device *gio_dev = to_gio_device(dev);

        add_uevent_var(env, "MODALIAS=gio:%x", gio_dev->id.id);
        return 0;
}

int gio_register_driver(struct gio_driver *drv)
{
        /* initialize common driver fields */
        if (!drv->driver.name)
                drv->driver.name = drv->name;
        if (!drv->driver.owner)
                drv->driver.owner = drv->owner;
        drv->driver.bus = &gio_bus_type;

        /* register with core */
        return driver_register(&drv->driver);
}
EXPORT_SYMBOL_GPL(gio_register_driver);

void gio_unregister_driver(struct gio_driver *drv)
{
        driver_unregister(&drv->driver);
}
EXPORT_SYMBOL_GPL(gio_unregister_driver);

void gio_set_master(struct gio_device *dev)
{
        u32 tmp = sgimc->giopar;

        switch (dev->slotno) {
        case 0:
                tmp |= SGIMC_GIOPAR_MASTERGFX;
                break;
        case 1:
                tmp |= SGIMC_GIOPAR_MASTEREXP0;
                break;
        case 2:
                tmp |= SGIMC_GIOPAR_MASTEREXP1;
                break;
        }
        sgimc->giopar = tmp;
}
EXPORT_SYMBOL_GPL(gio_set_master);

static void ip22_gio_set_64bit(int slotno)
{
        u32 tmp = sgimc->giopar;

        switch (slotno) {
        case 0:
                tmp |= SGIMC_GIOPAR_GFX64;
                break;
        case 1:
                tmp |= SGIMC_GIOPAR_EXP064;
                break;
        case 2:
                tmp |= SGIMC_GIOPAR_EXP164;
                break;
        }
        sgimc->giopar = tmp;
}

static int ip22_gio_id(unsigned long addr, u32 *res)
{
        u8 tmp8;
        u8 tmp16;
        u32 tmp32;
        u8 *ptr8;
        u16 *ptr16;
        u32 *ptr32;

        ptr32 = (void *)CKSEG1ADDR(addr);
        if (!get_dbe(tmp32, ptr32)) {
                /*
                 * We got no DBE, but this doesn't mean anything.
                 * If GIO is pipelined (which can't be disabled
                 * for GFX slot) we don't get a DBE, but we see
                 * the transfer size as data. So we do an 8bit
                 * and a 16bit access and check whether the common
                 * data matches
                 */
                ptr8 = (void *)CKSEG1ADDR(addr + 3);
                if (get_dbe(tmp8, ptr8)) {
                        /*
                         * 32bit access worked, but 8bit doesn't
                         * so we don't see phantom reads on
                         * a pipelined bus, but a real card which
                         * doesn't support 8 bit reads
                         */
                        *res = tmp32;
                        return 1;
                }
                ptr16 = (void *)CKSEG1ADDR(addr + 2);
                get_dbe(tmp16, ptr16);
                if (tmp8 == (tmp16 & 0xff) &&
                    tmp8 == (tmp32 & 0xff) &&
                    tmp16 == (tmp32 & 0xffff)) {
                        *res = tmp32;
                        return 1;
                }
        }
        return 0; /* nothing here */
}

#define HQ2_MYSTERY_OFFS       0x6A07C
#define NEWPORT_USTATUS_OFFS   0xF133C

static int ip22_is_gr2(unsigned long addr)
{
        u32 tmp;
        u32 *ptr;

        /* HQ2 only allows 32bit accesses */
        ptr = (void *)CKSEG1ADDR(addr + HQ2_MYSTERY_OFFS);
        if (!get_dbe(tmp, ptr)) {
                if (tmp == 0xdeadbeef)
                        return 1;
        }
        return 0;
}


static void ip22_check_gio(int slotno, unsigned long addr, int irq)
{
        const char *name = "Unknown";
        struct gio_device *gio_dev;
        u32 tmp;
        __u8 id;
        int i;

        /* first look for GR2/GR3 by checking mystery register */
        if (ip22_is_gr2(addr))
                tmp = 0x7f;
        else {
                if (!ip22_gio_id(addr, &tmp)) {
                        /*
                         * no GIO signature at start address of slot
                         * since Newport doesn't have one, we check if
                         * user status register is readable
                         */
                        if (ip22_gio_id(addr + NEWPORT_USTATUS_OFFS, &tmp))
                                tmp = 0x7e;
                        else
                                tmp = 0;
                }
        }
        if (tmp) {
                id = GIO_ID(tmp);
                if (tmp & GIO_32BIT_ID) {
                        if (tmp & GIO_64BIT_IFACE)
                                ip22_gio_set_64bit(slotno);
                }
                for (i = 0; i < ARRAY_SIZE(gio_name_table); i++) {
                        if (id == gio_name_table[i].id) {
                                name = gio_name_table[i].name;
                                break;
                        }
                }
                printk(KERN_INFO "GIO: slot %d : %s (id %x)\n",
                       slotno, name, id);
                gio_dev = kzalloc_obj(*gio_dev);
                if (!gio_dev)
                        return;
                gio_dev->name = name;
                gio_dev->slotno = slotno;
                gio_dev->id.id = id;
                gio_dev->resource.start = addr;
                gio_dev->resource.end = addr + 0x3fffff;
                gio_dev->resource.flags = IORESOURCE_MEM;
                gio_dev->irq = irq;
                dev_set_name(&gio_dev->dev, "%d", slotno);
                if (gio_device_register(gio_dev))
                        gio_dev_put(gio_dev);
        } else
                printk(KERN_INFO "GIO: slot %d : Empty\n", slotno);
}

static const struct bus_type gio_bus_type = {
        .name      = "gio",
        .dev_groups = gio_dev_groups,
        .match     = gio_bus_match,
        .probe     = gio_device_probe,
        .remove    = gio_device_remove,
        .shutdown  = gio_device_shutdown,
        .uevent    = gio_device_uevent,
};

static struct resource gio_bus_resource = {
        .start = GIO_SLOT_GFX_BASE,
        .end   = GIO_SLOT_GFX_BASE + 0x9fffff,
        .name  = "GIO Bus",
        .flags = IORESOURCE_MEM,
};

static int __init ip22_gio_init(void)
{
        unsigned int pbdma __maybe_unused;
        int ret;

        ret = device_register(&gio_bus);
        if (ret) {
                put_device(&gio_bus);
                return ret;
        }

        ret = bus_register(&gio_bus_type);
        if (!ret) {
                request_resource(&iomem_resource, &gio_bus_resource);
                printk(KERN_INFO "GIO: Probing bus...\n");

                if (ip22_is_fullhouse()) {
                        /* Indigo2 */
                        ip22_check_gio(0, GIO_SLOT_GFX_BASE, SGI_GIO_1_IRQ);
                        ip22_check_gio(1, GIO_SLOT_EXP0_BASE, SGI_GIO_1_IRQ);
                } else {
                        /* Indy/Challenge S */
                        if (get_dbe(pbdma, (unsigned int *)&hpc3c1->pbdma[1]))
                                ip22_check_gio(0, GIO_SLOT_GFX_BASE,
                                               SGI_GIO_0_IRQ);
                        ip22_check_gio(1, GIO_SLOT_EXP0_BASE, SGI_GIOEXP0_IRQ);
                        ip22_check_gio(2, GIO_SLOT_EXP1_BASE, SGI_GIOEXP1_IRQ);
                }
        } else
                device_unregister(&gio_bus);

        return ret;
}

subsys_initcall(ip22_gio_init);