quickstart.c

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/*
 *  quickstart.c - ACPI Direct App Launch driver
 *
 *
 *  Copyright (C) 2007-2010 Angelo Arrifano <[email protected]>
 *
 *  Information gathered from disassembled dsdt and from here:
 *  <http://www.microsoft.com/whdc/system/platform/firmware/DirAppLaunch.mspx>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#define QUICKSTART_VERSION "1.04"

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <acpi/acpi_drivers.h>
#include <linux/platform_device.h>
#include <linux/input.h>

MODULE_AUTHOR("Angelo Arrifano");
MODULE_DESCRIPTION("ACPI Direct App Launch driver");
MODULE_LICENSE("GPL");

#define QUICKSTART_ACPI_DEVICE_NAME "quickstart"
#define QUICKSTART_ACPI_CLASS       "quickstart"
#define QUICKSTART_ACPI_HID     "PNP0C32"

#define QUICKSTART_PF_DRIVER_NAME   "quickstart"
#define QUICKSTART_PF_DEVICE_NAME   "quickstart"

/*
 * There will be two events:
 * 0x02 - A hot button was pressed while device was off/sleeping.
 * 0x80 - A hot button was pressed while device was up.
 */
#define QUICKSTART_EVENT_WAKE       0x02
#define QUICKSTART_EVENT_RUNTIME    0x80

struct quickstart_button {
    char *name;
    unsigned int id;
    struct list_head list;
};

struct quickstart_acpi {
    struct acpi_device *device;
    struct quickstart_button *button;
};

static LIST_HEAD(buttons);
static struct quickstart_button *pressed;

static struct input_dev *quickstart_input;

/* Platform driver functions */
static ssize_t quickstart_buttons_show(struct device *dev,
                    struct device_attribute *attr,
                    char *buf)
{
    int count = 0;
    struct quickstart_button *b;

    if (list_empty(&buttons))
        return snprintf(buf, PAGE_SIZE, "none");

    list_for_each_entry(b, &buttons, list) {
        count += snprintf(buf + count, PAGE_SIZE - count, "%u\t%s\n",
                            b->id, b->name);

        if (count >= PAGE_SIZE) {
            count = PAGE_SIZE;
            break;
        }
    }

    return count;
}

static ssize_t quickstart_pressed_button_show(struct device *dev,
                        struct device_attribute *attr,
                        char *buf)
{
    return scnprintf(buf, PAGE_SIZE, "%s\n",
                    (pressed ? pressed->name : "none"));
}


static ssize_t quickstart_pressed_button_store(struct device *dev,
                        struct device_attribute *attr,
                        const char *buf, size_t count)
{
    if (count < 2)
        return -EINVAL;

    if (strncasecmp(buf, "none", 4) != 0)
        return -EINVAL;

    pressed = NULL;
    return count;
}

/* Helper functions */
static struct quickstart_button *quickstart_buttons_add(void)
{
    struct quickstart_button *b;

    b = kzalloc(sizeof(*b), GFP_KERNEL);
    if (!b)
        return NULL;

    list_add_tail(&b->list, &buttons);

    return b;
}

static void quickstart_button_del(struct quickstart_button *data)
{
    if (!data)
        return;

    list_del(&data->list);
    kfree(data->name);
    kfree(data);
}

static void quickstart_buttons_free(void)
{
    struct quickstart_button *b, *n;

    list_for_each_entry_safe(b, n, &buttons, list)
        quickstart_button_del(b);
}

/* ACPI Driver functions */
static void quickstart_acpi_notify(acpi_handle handle, u32 event, void *data)
{
    struct quickstart_acpi *quickstart = data;

    if (!quickstart)
        return;

    switch (event) {
    case QUICKSTART_EVENT_WAKE:
        pressed = quickstart->button;
        break;
    case QUICKSTART_EVENT_RUNTIME:
        input_report_key(quickstart_input, quickstart->button->id, 1);
        input_sync(quickstart_input);
        input_report_key(quickstart_input, quickstart->button->id, 0);
        input_sync(quickstart_input);
        break;
    default:
        pr_err("Unexpected ACPI event notify (%u)\n", event);
        break;
    }
}

static int quickstart_acpi_ghid(struct quickstart_acpi *quickstart)
{
    acpi_status status;
    struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
    int ret = 0;

    /*
     * This returns a buffer telling the button usage ID,
     * and triggers pending notify events (The ones before booting).
     */
    status = acpi_evaluate_object(quickstart->device->handle, "GHID", NULL,
                                &buffer);
    if (ACPI_FAILURE(status)) {
        pr_err("%s GHID method failed\n", quickstart->button->name);
        return -EINVAL;
    }

    /*
     * <<The GHID method can return a BYTE, WORD, or DWORD.
     * The value must be encoded in little-endian byte
     * order (least significant byte first).>>
     */
    switch (buffer.length) {
    case 1:
        quickstart->button->id = *(uint8_t *)buffer.pointer;
        break;
    case 2:
        quickstart->button->id = *(uint16_t *)buffer.pointer;
        break;
    case 4:
        quickstart->button->id = *(uint32_t *)buffer.pointer;
        break;
    case 8:
        quickstart->button->id = *(uint64_t *)buffer.pointer;
        break;
    default:
        pr_err("%s GHID method returned buffer of unexpected length %lu\n",
                quickstart->button->name,
                (unsigned long)buffer.length);
        ret = -EINVAL;
        break;
    }

    kfree(buffer.pointer);

    return ret;
}

static int quickstart_acpi_config(struct quickstart_acpi *quickstart)
{
    char *bid = acpi_device_bid(quickstart->device);
    char *name;

    name = kmalloc(strlen(bid) + 1, GFP_KERNEL);
    if (!name)
        return -ENOMEM;

    /* Add new button to list */
    quickstart->button = quickstart_buttons_add();
    if (!quickstart->button) {
        kfree(name);
        return -ENOMEM;
    }

    quickstart->button->name = name;
    strcpy(quickstart->button->name, bid);

    return 0;
}

static int quickstart_acpi_add(struct acpi_device *device)
{
    int ret;
    acpi_status status;
    struct quickstart_acpi *quickstart;

    if (!device)
        return -EINVAL;

    quickstart = kzalloc(sizeof(*quickstart), GFP_KERNEL);
    if (!quickstart)
        return -ENOMEM;

    quickstart->device = device;

    strcpy(acpi_device_name(device), QUICKSTART_ACPI_DEVICE_NAME);
    strcpy(acpi_device_class(device), QUICKSTART_ACPI_CLASS);
    device->driver_data = quickstart;

    /* Add button to list and initialize some stuff */
    ret = quickstart_acpi_config(quickstart);
    if (ret < 0)
        goto fail_config;

    status = acpi_install_notify_handler(device->handle, ACPI_ALL_NOTIFY,
                        quickstart_acpi_notify,
                        quickstart);
    if (ACPI_FAILURE(status)) {
        pr_err("Notify handler install error\n");
        ret = -ENODEV;
        goto fail_installnotify;
    }

    ret = quickstart_acpi_ghid(quickstart);
    if (ret < 0)
        goto fail_ghid;

    return 0;

fail_ghid:
    acpi_remove_notify_handler(device->handle, ACPI_ALL_NOTIFY,
                        quickstart_acpi_notify);

fail_installnotify:
    quickstart_button_del(quickstart->button);

fail_config:

    kfree(quickstart);

    return ret;
}

static int quickstart_acpi_remove(struct acpi_device *device, int type)
{
    acpi_status status;
    struct quickstart_acpi *quickstart;

    if (!device)
        return -EINVAL;

    quickstart = acpi_driver_data(device);
    if (!quickstart)
        return -EINVAL;

    status = acpi_remove_notify_handler(device->handle, ACPI_ALL_NOTIFY,
                        quickstart_acpi_notify);
    if (ACPI_FAILURE(status))
        pr_err("Error removing notify handler\n");

    kfree(quickstart);

    return 0;
}

/* Platform driver structs */
static DEVICE_ATTR(pressed_button, 0666, quickstart_pressed_button_show,
                     quickstart_pressed_button_store);
static DEVICE_ATTR(buttons, 0444, quickstart_buttons_show, NULL);
static struct platform_device *pf_device;
static struct platform_driver pf_driver = {
    .driver = {
        .name = QUICKSTART_PF_DRIVER_NAME,
        .owner = THIS_MODULE,
    }
};

static const struct acpi_device_id quickstart_device_ids[] = {
    {QUICKSTART_ACPI_HID, 0},
    {"", 0},
};

static struct acpi_driver quickstart_acpi_driver = {
    .name = "quickstart",
    .class = QUICKSTART_ACPI_CLASS,
    .ids = quickstart_device_ids,
    .ops = {
            .add = quickstart_acpi_add,
            .remove = quickstart_acpi_remove,
        },
};

/* Module functions */
static void quickstart_exit(void)
{
    input_unregister_device(quickstart_input);

    device_remove_file(&pf_device->dev, &dev_attr_pressed_button);
    device_remove_file(&pf_device->dev, &dev_attr_buttons);

    platform_device_unregister(pf_device);

    platform_driver_unregister(&pf_driver);

    acpi_bus_unregister_driver(&quickstart_acpi_driver);

    quickstart_buttons_free();
}

static int __init quickstart_init_input(void)
{
    struct quickstart_button *b;
    int ret;

    quickstart_input = input_allocate_device();

    if (!quickstart_input)
        return -ENOMEM;

    quickstart_input->name = "Quickstart ACPI Buttons";
    quickstart_input->id.bustype = BUS_HOST;

    list_for_each_entry(b, &buttons, list) {
        set_bit(EV_KEY, quickstart_input->evbit);
        set_bit(b->id, quickstart_input->keybit);
    }

    ret = input_register_device(quickstart_input);
    if (ret) {
        input_free_device(quickstart_input);
        return ret;
    }

    return 0;
}

static int __init quickstart_init(void)
{
    int ret;

    /* ACPI Check */
    if (acpi_disabled)
        return -ENODEV;

    /* ACPI driver register */
    ret = acpi_bus_register_driver(&quickstart_acpi_driver);
    if (ret)
        return ret;

    /* If existing bus with no devices */
    if (list_empty(&buttons)) {
        ret = -ENODEV;
        goto fail_pfdrv_reg;
    }

    /* Platform driver register */
    ret = platform_driver_register(&pf_driver);
    if (ret)
        goto fail_pfdrv_reg;

    /* Platform device register */
    pf_device = platform_device_alloc(QUICKSTART_PF_DEVICE_NAME, -1);
    if (!pf_device) {
        ret = -ENOMEM;
        goto fail_pfdev_alloc;
    }
    ret = platform_device_add(pf_device);
    if (ret)
        goto fail_pfdev_add;

    /* Create device sysfs file */
    ret = device_create_file(&pf_device->dev, &dev_attr_pressed_button);
    if (ret)
        goto fail_dev_file;

    ret = device_create_file(&pf_device->dev, &dev_attr_buttons);
    if (ret)
        goto fail_dev_file2;

    /* Input device */
    ret = quickstart_init_input();
    if (ret)
        goto fail_input;

    pr_info("ACPI Direct App Launch ver %s\n", QUICKSTART_VERSION);

    return 0;
fail_input:
    device_remove_file(&pf_device->dev, &dev_attr_buttons);

fail_dev_file2:
    device_remove_file(&pf_device->dev, &dev_attr_pressed_button);

fail_dev_file:
    platform_device_del(pf_device);

fail_pfdev_add:
    platform_device_put(pf_device);

fail_pfdev_alloc:
    platform_driver_unregister(&pf_driver);

fail_pfdrv_reg:
    acpi_bus_unregister_driver(&quickstart_acpi_driver);

    return ret;
}

module_init(quickstart_init);
module_exit(quickstart_exit);