apple-gmux.c

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/*
 *  Gmux driver for Apple laptops
 *
 *  Copyright (C) Canonical Ltd. <[email protected]>
 *  Copyright (C) 2010-2012 Andreas Heider <[email protected]>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/backlight.h>
#include <linux/acpi.h>
#include <linux/pnp.h>
#include <linux/apple_bl.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/pci.h>
#include <linux/vga_switcheroo.h>
#include <acpi/video.h>
#include <asm/io.h>

struct apple_gmux_data {
    unsigned long iostart;
    unsigned long iolen;
    bool indexed;
    struct mutex index_lock;

    struct backlight_device *bdev;

    /* switcheroo data */
    acpi_handle dhandle;
    int gpe;
    enum vga_switcheroo_client_id resume_client_id;
    enum vga_switcheroo_state power_state;
    struct completion powerchange_done;
};

static struct apple_gmux_data *apple_gmux_data;

/*
 * gmux port offsets. Many of these are not yet used, but may be in the
 * future, and it's useful to have them documented here anyhow.
 */
#define GMUX_PORT_VERSION_MAJOR     0x04
#define GMUX_PORT_VERSION_MINOR     0x05
#define GMUX_PORT_VERSION_RELEASE   0x06
#define GMUX_PORT_SWITCH_DISPLAY    0x10
#define GMUX_PORT_SWITCH_GET_DISPLAY    0x11
#define GMUX_PORT_INTERRUPT_ENABLE  0x14
#define GMUX_PORT_INTERRUPT_STATUS  0x16
#define GMUX_PORT_SWITCH_DDC        0x28
#define GMUX_PORT_SWITCH_EXTERNAL   0x40
#define GMUX_PORT_SWITCH_GET_EXTERNAL   0x41
#define GMUX_PORT_DISCRETE_POWER    0x50
#define GMUX_PORT_MAX_BRIGHTNESS    0x70
#define GMUX_PORT_BRIGHTNESS        0x74
#define GMUX_PORT_VALUE         0xc2
#define GMUX_PORT_READ          0xd0
#define GMUX_PORT_WRITE         0xd4

#define GMUX_MIN_IO_LEN         (GMUX_PORT_BRIGHTNESS + 4)

#define GMUX_INTERRUPT_ENABLE       0xff
#define GMUX_INTERRUPT_DISABLE      0x00

#define GMUX_INTERRUPT_STATUS_ACTIVE    0
#define GMUX_INTERRUPT_STATUS_DISPLAY   (1 << 0)
#define GMUX_INTERRUPT_STATUS_POWER (1 << 2)
#define GMUX_INTERRUPT_STATUS_HOTPLUG   (1 << 3)

#define GMUX_BRIGHTNESS_MASK        0x00ffffff
#define GMUX_MAX_BRIGHTNESS     GMUX_BRIGHTNESS_MASK

static u8 gmux_pio_read8(struct apple_gmux_data *gmux_data, int port)
{
    return inb(gmux_data->iostart + port);
}

static void gmux_pio_write8(struct apple_gmux_data *gmux_data, int port,
                   u8 val)
{
    outb(val, gmux_data->iostart + port);
}

static u32 gmux_pio_read32(struct apple_gmux_data *gmux_data, int port)
{
    return inl(gmux_data->iostart + port);
}

static void gmux_pio_write32(struct apple_gmux_data *gmux_data, int port,
                 u32 val)
{
    int i;
    u8 tmpval;

    for (i = 0; i < 4; i++) {
        tmpval = (val >> (i * 8)) & 0xff;
        outb(tmpval, gmux_data->iostart + port + i);
    }
}

static int gmux_index_wait_ready(struct apple_gmux_data *gmux_data)
{
    int i = 200;
    u8 gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);

    while (i && (gwr & 0x01)) {
        inb(gmux_data->iostart + GMUX_PORT_READ);
        gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
        udelay(100);
        i--;
    }

    return !!i;
}

static int gmux_index_wait_complete(struct apple_gmux_data *gmux_data)
{
    int i = 200;
    u8 gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);

    while (i && !(gwr & 0x01)) {
        gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
        udelay(100);
        i--;
    }

    if (gwr & 0x01)
        inb(gmux_data->iostart + GMUX_PORT_READ);

    return !!i;
}

static u8 gmux_index_read8(struct apple_gmux_data *gmux_data, int port)
{
    u8 val;

    mutex_lock(&gmux_data->index_lock);
    gmux_index_wait_ready(gmux_data);
    outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
    gmux_index_wait_complete(gmux_data);
    val = inb(gmux_data->iostart + GMUX_PORT_VALUE);
    mutex_unlock(&gmux_data->index_lock);

    return val;
}

static void gmux_index_write8(struct apple_gmux_data *gmux_data, int port,
                  u8 val)
{
    mutex_lock(&gmux_data->index_lock);
    outb(val, gmux_data->iostart + GMUX_PORT_VALUE);
    gmux_index_wait_ready(gmux_data);
    outb(port & 0xff, gmux_data->iostart + GMUX_PORT_WRITE);
    gmux_index_wait_complete(gmux_data);
    mutex_unlock(&gmux_data->index_lock);
}

static u32 gmux_index_read32(struct apple_gmux_data *gmux_data, int port)
{
    u32 val;

    mutex_lock(&gmux_data->index_lock);
    gmux_index_wait_ready(gmux_data);
    outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
    gmux_index_wait_complete(gmux_data);
    val = inl(gmux_data->iostart + GMUX_PORT_VALUE);
    mutex_unlock(&gmux_data->index_lock);

    return val;
}

static void gmux_index_write32(struct apple_gmux_data *gmux_data, int port,
                   u32 val)
{
    int i;
    u8 tmpval;

    mutex_lock(&gmux_data->index_lock);

    for (i = 0; i < 4; i++) {
        tmpval = (val >> (i * 8)) & 0xff;
        outb(tmpval, gmux_data->iostart + GMUX_PORT_VALUE + i);
    }

    gmux_index_wait_ready(gmux_data);
    outb(port & 0xff, gmux_data->iostart + GMUX_PORT_WRITE);
    gmux_index_wait_complete(gmux_data);
    mutex_unlock(&gmux_data->index_lock);
}

static u8 gmux_read8(struct apple_gmux_data *gmux_data, int port)
{
    if (gmux_data->indexed)
        return gmux_index_read8(gmux_data, port);
    else
        return gmux_pio_read8(gmux_data, port);
}

static void gmux_write8(struct apple_gmux_data *gmux_data, int port, u8 val)
{
    if (gmux_data->indexed)
        gmux_index_write8(gmux_data, port, val);
    else
        gmux_pio_write8(gmux_data, port, val);
}

static u32 gmux_read32(struct apple_gmux_data *gmux_data, int port)
{
    if (gmux_data->indexed)
        return gmux_index_read32(gmux_data, port);
    else
        return gmux_pio_read32(gmux_data, port);
}

static void gmux_write32(struct apple_gmux_data *gmux_data, int port,
                 u32 val)
{
    if (gmux_data->indexed)
        gmux_index_write32(gmux_data, port, val);
    else
        gmux_pio_write32(gmux_data, port, val);
}

static bool gmux_is_indexed(struct apple_gmux_data *gmux_data)
{
    u16 val;

    outb(0xaa, gmux_data->iostart + 0xcc);
    outb(0x55, gmux_data->iostart + 0xcd);
    outb(0x00, gmux_data->iostart + 0xce);

    val = inb(gmux_data->iostart + 0xcc) |
        (inb(gmux_data->iostart + 0xcd) << 8);

    if (val == 0x55aa)
        return true;

    return false;
}

static int gmux_get_brightness(struct backlight_device *bd)
{
    struct apple_gmux_data *gmux_data = bl_get_data(bd);
    return gmux_read32(gmux_data, GMUX_PORT_BRIGHTNESS) &
           GMUX_BRIGHTNESS_MASK;
}

static int gmux_update_status(struct backlight_device *bd)
{
    struct apple_gmux_data *gmux_data = bl_get_data(bd);
    u32 brightness = bd->props.brightness;

    if (bd->props.state & BL_CORE_SUSPENDED)
        return 0;

    gmux_write32(gmux_data, GMUX_PORT_BRIGHTNESS, brightness);

    return 0;
}

static const struct backlight_ops gmux_bl_ops = {
    .options = BL_CORE_SUSPENDRESUME,
    .get_brightness = gmux_get_brightness,
    .update_status = gmux_update_status,
};

static int gmux_switchto(enum vga_switcheroo_client_id id)
{
    if (id == VGA_SWITCHEROO_IGD) {
        gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 1);
        gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DISPLAY, 2);
        gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 2);
    } else {
        gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 2);
        gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DISPLAY, 3);
        gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 3);
    }

    return 0;
}

static int gmux_set_discrete_state(struct apple_gmux_data *gmux_data,
                   enum vga_switcheroo_state state)
{
    INIT_COMPLETION(gmux_data->powerchange_done);

    if (state == VGA_SWITCHEROO_ON) {
        gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 1);
        gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 3);
        pr_debug("Discrete card powered up\n");
    } else {
        gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 1);
        gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 0);
        pr_debug("Discrete card powered down\n");
    }

    gmux_data->power_state = state;

    if (gmux_data->gpe >= 0 &&
        !wait_for_completion_interruptible_timeout(&gmux_data->powerchange_done,
                               msecs_to_jiffies(200)))
        pr_warn("Timeout waiting for gmux switch to complete\n");

    return 0;
}

static int gmux_set_power_state(enum vga_switcheroo_client_id id,
                enum vga_switcheroo_state state)
{
    if (id == VGA_SWITCHEROO_IGD)
        return 0;

    return gmux_set_discrete_state(apple_gmux_data, state);
}

static int gmux_get_client_id(struct pci_dev *pdev)
{
    /*
     * Early Macbook Pros with switchable graphics use nvidia
     * integrated graphics. Hardcode that the 9400M is integrated.
     */
    if (pdev->vendor == PCI_VENDOR_ID_INTEL)
        return VGA_SWITCHEROO_IGD;
    else if (pdev->vendor == PCI_VENDOR_ID_NVIDIA &&
         pdev->device == 0x0863)
        return VGA_SWITCHEROO_IGD;
    else
        return VGA_SWITCHEROO_DIS;
}

static enum vga_switcheroo_client_id
gmux_active_client(struct apple_gmux_data *gmux_data)
{
    if (gmux_read8(gmux_data, GMUX_PORT_SWITCH_DISPLAY) == 2)
        return VGA_SWITCHEROO_IGD;

    return VGA_SWITCHEROO_DIS;
}

static struct vga_switcheroo_handler gmux_handler = {
    .switchto = gmux_switchto,
    .power_state = gmux_set_power_state,
    .get_client_id = gmux_get_client_id,
};

static inline void gmux_disable_interrupts(struct apple_gmux_data *gmux_data)
{
    gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_ENABLE,
            GMUX_INTERRUPT_DISABLE);
}

static inline void gmux_enable_interrupts(struct apple_gmux_data *gmux_data)
{
    gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_ENABLE,
            GMUX_INTERRUPT_ENABLE);
}

static inline u8 gmux_interrupt_get_status(struct apple_gmux_data *gmux_data)
{
    return gmux_read8(gmux_data, GMUX_PORT_INTERRUPT_STATUS);
}

static void gmux_clear_interrupts(struct apple_gmux_data *gmux_data)
{
    u8 status;

    /* to clear interrupts write back current status */
    status = gmux_interrupt_get_status(gmux_data);
    gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_STATUS, status);
}

static void gmux_notify_handler(acpi_handle device, u32 value, void *context)
{
    u8 status;
    struct pnp_dev *pnp = (struct pnp_dev *)context;
    struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);

    status = gmux_interrupt_get_status(gmux_data);
    gmux_disable_interrupts(gmux_data);
    pr_debug("Notify handler called: status %d\n", status);

    gmux_clear_interrupts(gmux_data);
    gmux_enable_interrupts(gmux_data);

    if (status & GMUX_INTERRUPT_STATUS_POWER)
        complete(&gmux_data->powerchange_done);
}

static int gmux_suspend(struct pnp_dev *pnp, pm_message_t state)
{
    struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
    gmux_data->resume_client_id = gmux_active_client(gmux_data);
    gmux_disable_interrupts(gmux_data);
    return 0;
}

static int gmux_resume(struct pnp_dev *pnp)
{
    struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
    gmux_enable_interrupts(gmux_data);
    gmux_switchto(gmux_data->resume_client_id);
    if (gmux_data->power_state == VGA_SWITCHEROO_OFF)
        gmux_set_discrete_state(gmux_data, gmux_data->power_state);
    return 0;
}

static int __devinit gmux_probe(struct pnp_dev *pnp,
                const struct pnp_device_id *id)
{
    struct apple_gmux_data *gmux_data;
    struct resource *res;
    struct backlight_properties props;
    struct backlight_device *bdev;
    u8 ver_major, ver_minor, ver_release;
    int ret = -ENXIO;
    acpi_status status;
    unsigned long long gpe;

    if (apple_gmux_data)
        return -EBUSY;

    gmux_data = kzalloc(sizeof(*gmux_data), GFP_KERNEL);
    if (!gmux_data)
        return -ENOMEM;
    pnp_set_drvdata(pnp, gmux_data);

    res = pnp_get_resource(pnp, IORESOURCE_IO, 0);
    if (!res) {
        pr_err("Failed to find gmux I/O resource\n");
        goto err_free;
    }

    gmux_data->iostart = res->start;
    gmux_data->iolen = res->end - res->start;

    if (gmux_data->iolen < GMUX_MIN_IO_LEN) {
        pr_err("gmux I/O region too small (%lu < %u)\n",
               gmux_data->iolen, GMUX_MIN_IO_LEN);
        goto err_free;
    }

    if (!request_region(gmux_data->iostart, gmux_data->iolen,
                "Apple gmux")) {
        pr_err("gmux I/O already in use\n");
        goto err_free;
    }

    /*
     * Invalid version information may indicate either that the gmux
     * device isn't present or that it's a new one that uses indexed
     * io
     */

    ver_major = gmux_read8(gmux_data, GMUX_PORT_VERSION_MAJOR);
    ver_minor = gmux_read8(gmux_data, GMUX_PORT_VERSION_MINOR);
    ver_release = gmux_read8(gmux_data, GMUX_PORT_VERSION_RELEASE);
    if (ver_major == 0xff && ver_minor == 0xff && ver_release == 0xff) {
        if (gmux_is_indexed(gmux_data)) {
            u32 version;
            mutex_init(&gmux_data->index_lock);
            gmux_data->indexed = true;
            version = gmux_read32(gmux_data,
                GMUX_PORT_VERSION_MAJOR);
            ver_major = (version >> 24) & 0xff;
            ver_minor = (version >> 16) & 0xff;
            ver_release = (version >> 8) & 0xff;
        } else {
            pr_info("gmux device not present\n");
            ret = -ENODEV;
            goto err_release;
        }
    }
    pr_info("Found gmux version %d.%d.%d [%s]\n", ver_major, ver_minor,
        ver_release, (gmux_data->indexed ? "indexed" : "classic"));

    memset(&props, 0, sizeof(props));
    props.type = BACKLIGHT_PLATFORM;
    props.max_brightness = gmux_read32(gmux_data, GMUX_PORT_MAX_BRIGHTNESS);

    /*
     * Currently it's assumed that the maximum brightness is less than
     * 2^24 for compatibility with old gmux versions. Cap the max
     * brightness at this value, but print a warning if the hardware
     * reports something higher so that it can be fixed.
     */
    if (WARN_ON(props.max_brightness > GMUX_MAX_BRIGHTNESS))
        props.max_brightness = GMUX_MAX_BRIGHTNESS;

    bdev = backlight_device_register("gmux_backlight", &pnp->dev,
                     gmux_data, &gmux_bl_ops, &props);
    if (IS_ERR(bdev)) {
        ret = PTR_ERR(bdev);
        goto err_release;
    }

    gmux_data->bdev = bdev;
    bdev->props.brightness = gmux_get_brightness(bdev);
    backlight_update_status(bdev);

    /*
     * The backlight situation on Macs is complicated. If the gmux is
     * present it's the best choice, because it always works for
     * backlight control and supports more levels than other options.
     * Disable the other backlight choices.
     */
    acpi_video_dmi_promote_vendor();
    acpi_video_unregister();
    apple_bl_unregister();

    gmux_data->power_state = VGA_SWITCHEROO_ON;

    gmux_data->dhandle = DEVICE_ACPI_HANDLE(&pnp->dev);
    if (!gmux_data->dhandle) {
        pr_err("Cannot find acpi handle for pnp device %s\n",
               dev_name(&pnp->dev));
        ret = -ENODEV;
        goto err_notify;
    }

    status = acpi_evaluate_integer(gmux_data->dhandle, "GMGP", NULL, &gpe);
    if (ACPI_SUCCESS(status)) {
        gmux_data->gpe = (int)gpe;

        status = acpi_install_notify_handler(gmux_data->dhandle,
                             ACPI_DEVICE_NOTIFY,
                             &gmux_notify_handler, pnp);
        if (ACPI_FAILURE(status)) {
            pr_err("Install notify handler failed: %s\n",
                   acpi_format_exception(status));
            ret = -ENODEV;
            goto err_notify;
        }

        status = acpi_enable_gpe(NULL, gmux_data->gpe);
        if (ACPI_FAILURE(status)) {
            pr_err("Cannot enable gpe: %s\n",
                   acpi_format_exception(status));
            goto err_enable_gpe;
        }
    } else {
        pr_warn("No GPE found for gmux\n");
        gmux_data->gpe = -1;
    }

    if (vga_switcheroo_register_handler(&gmux_handler)) {
        ret = -ENODEV;
        goto err_register_handler;
    }

    init_completion(&gmux_data->powerchange_done);
    apple_gmux_data = gmux_data;
    gmux_enable_interrupts(gmux_data);

    return 0;

err_register_handler:
    if (gmux_data->gpe >= 0)
        acpi_disable_gpe(NULL, gmux_data->gpe);
err_enable_gpe:
    if (gmux_data->gpe >= 0)
        acpi_remove_notify_handler(gmux_data->dhandle,
                       ACPI_DEVICE_NOTIFY,
                       &gmux_notify_handler);
err_notify:
    backlight_device_unregister(bdev);
err_release:
    release_region(gmux_data->iostart, gmux_data->iolen);
err_free:
    kfree(gmux_data);
    return ret;
}

static void __devexit gmux_remove(struct pnp_dev *pnp)
{
    struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);

    vga_switcheroo_unregister_handler();
    gmux_disable_interrupts(gmux_data);
    if (gmux_data->gpe >= 0) {
        acpi_disable_gpe(NULL, gmux_data->gpe);
        acpi_remove_notify_handler(gmux_data->dhandle,
                       ACPI_DEVICE_NOTIFY,
                       &gmux_notify_handler);
    }

    backlight_device_unregister(gmux_data->bdev);

    release_region(gmux_data->iostart, gmux_data->iolen);
    apple_gmux_data = NULL;
    kfree(gmux_data);

    acpi_video_dmi_demote_vendor();
    acpi_video_register();
    apple_bl_register();
}

static const struct pnp_device_id gmux_device_ids[] = {
    {"APP000B", 0},
    {"", 0}
};

static struct pnp_driver gmux_pnp_driver = {
    .name       = "apple-gmux",
    .probe      = gmux_probe,
    .remove     = __devexit_p(gmux_remove),
    .id_table   = gmux_device_ids,
    .suspend    = gmux_suspend,
    .resume     = gmux_resume
};

static int __init apple_gmux_init(void)
{
    return pnp_register_driver(&gmux_pnp_driver);
}

static void __exit apple_gmux_exit(void)
{
    pnp_unregister_driver(&gmux_pnp_driver);
}

module_init(apple_gmux_init);
module_exit(apple_gmux_exit);

MODULE_AUTHOR("Seth Forshee <[email protected]>");
MODULE_DESCRIPTION("Apple Gmux Driver");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(pnp, gmux_device_ids);