/*
 *  quickstart.c - ACPI Direct App Launch driver
 *
 *
 *  Copyright (C) 2007-2010 Angelo Arrifano <miknix@gmail.com>
 *
 *  Information gathered from disassebled 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 "1.03"

#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"
#define QUICKSTART_PF_DEVATTR_NAME    "pressed_button"

#define QUICKSTART_MAX_BTN_NAME_LEN   16

/* 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_btn {
        char *name;
        unsigned int id;
        struct quickstart_btn *next;
};

static struct quickstart_driver_data {
        struct quickstart_btn *btn_lst;
        struct quickstart_btn *pressed;
} quickstart_data;

/* ACPI driver Structs */
struct quickstart_acpi {
        struct acpi_device *device;
        struct quickstart_btn *btn;
};
static int quickstart_acpi_add(struct acpi_device *device);
static int quickstart_acpi_remove(struct acpi_device *device, int type);
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,
                },
};

/* Input device structs */
struct input_dev *quickstart_input;

/* Platform driver structs */
static ssize_t buttons_show(struct device *dev,
                                        struct device_attribute *attr,
                                        char *buf);
static ssize_t pressed_button_show(struct device *dev,
                                        struct device_attribute *attr,
                                        char *buf);
static ssize_t pressed_button_store(struct device *dev,
                                        struct device_attribute *attr,
                                         const char *buf,
                                         size_t count);
static DEVICE_ATTR(pressed_button, 0666, pressed_button_show,
                                         pressed_button_store);
static DEVICE_ATTR(buttons, 0444, buttons_show, NULL);
static struct platform_device *pf_device;
static struct platform_driver pf_driver = {
        .driver = {
                .name = QUICKSTART_PF_DRIVER_NAME,
                .owner = THIS_MODULE,
        }
};

/*
 * Platform driver functions
 */
static ssize_t buttons_show(struct device *dev,
                                         struct device_attribute *attr,
                                         char *buf)
{
        int count = 0;
        struct quickstart_btn *ptr = quickstart_data.btn_lst;

        if (!ptr)
                return snprintf(buf, PAGE_SIZE, "none");

        while (ptr && (count < PAGE_SIZE)) {
                if (ptr->name) {
                        count += snprintf(buf + count,
                                        PAGE_SIZE - count,
                                        "%d\t%s\n", ptr->id, ptr->name);
                }
                ptr = ptr->next;
        }

        return count;
}

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


static ssize_t 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;

        quickstart_data.pressed = NULL;
        return count;
}

/* Hotstart Helper functions */
static int quickstart_btnlst_add(struct quickstart_btn **data)
{
        struct quickstart_btn **ptr = &quickstart_data.btn_lst;

        while (*ptr)
                ptr = &((*ptr)->next);

        *ptr = kzalloc(sizeof(struct quickstart_btn), GFP_KERNEL);
        if (!*ptr) {
                *data = NULL;
                return -ENOMEM;
        }
        *data = *ptr;

        return 0;
}

static void quickstart_btnlst_del(struct quickstart_btn *data)
{
        struct quickstart_btn **ptr = &quickstart_data.btn_lst;

        if (!data)
                return;

        while (*ptr) {
                if (*ptr == data) {
                        *ptr = (*ptr)->next;
                        kfree(data);
                        return;
                }
                ptr = &((*ptr)->next);
        }

        return;
}

static void quickstart_btnlst_free(void)
{
        struct quickstart_btn *ptr = quickstart_data.btn_lst;
        struct quickstart_btn *lptr = NULL;

        while (ptr) {
                lptr = ptr;
                ptr = ptr->next;
                kfree(lptr->name);
                kfree(lptr);
        }

        return;
}

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

        if (!quickstart)
                return;

        if (event == QUICKSTART_EVENT_WAKE)
                quickstart_data.pressed = quickstart->btn;
        else if (event == QUICKSTART_EVENT_RUNTIME) {
                input_report_key(quickstart_input, quickstart->btn->id, 1);
                input_sync(quickstart_input);
                input_report_key(quickstart_input, quickstart->btn->id, 0);
                input_sync(quickstart_input);
        }
        return;
}

static void quickstart_acpi_ghid(struct quickstart_acpi *quickstart)
{
        acpi_status status;
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
        uint32_t usageid = 0;

        if (!quickstart)
                return;

        /* 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) || !buffer.pointer) {
                printk(KERN_ERR "quickstart: %s GHID method failed.\n",
                       quickstart->btn->name);
                return;
        }

        if (buffer.length < 8)
                return;

        /* <<The GHID method can return a BYTE, WORD, or DWORD.
         * The value must be encoded in little-endian byte
         * order (least significant byte first).>> */
        usageid = *((uint32_t *)(buffer.pointer + (buffer.length - 8)));
        quickstart->btn->id = usageid;

        kfree(buffer.pointer);
}

static int quickstart_acpi_config(struct quickstart_acpi *quickstart, char *bid)
{
        int len = strlen(bid);
        int ret;

        /* Add button to list */
        ret = quickstart_btnlst_add(&quickstart->btn);
        if (ret)
                return ret;

        quickstart->btn->name = kzalloc(len + 1, GFP_KERNEL);
        if (!quickstart->btn->name) {
                quickstart_btnlst_free();
                return -ENOMEM;
        }
        strcpy(quickstart->btn->name, bid);

        return 0;
}

static int quickstart_acpi_add(struct acpi_device *device)
{
        int ret = 0;
        acpi_status status = AE_OK;
        struct quickstart_acpi *quickstart = NULL;

        if (!device)
                return -EINVAL;

        quickstart = kzalloc(sizeof(struct quickstart_acpi), 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, acpi_device_bid(device));
        if (ret)
                goto fail_config;

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

        quickstart_acpi_ghid(quickstart);

        return 0;

fail_installnotify:
        quickstart_btnlst_del(quickstart->btn);

fail_config:

        kfree(quickstart);

        return ret;
}

static int quickstart_acpi_remove(struct acpi_device *device, int type)
{
        acpi_status status = 0;
        struct quickstart_acpi *quickstart = NULL;

        if (!device || !acpi_driver_data(device))
                return -EINVAL;

        quickstart = acpi_driver_data(device);

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


        kfree(quickstart);

        return 0;
}

/* 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_btnlst_free();

        return;
}

static int __init quickstart_init_input(void)
{
        struct quickstart_btn **ptr = &quickstart_data.btn_lst;
        int count;
        int ret;

        quickstart_input = input_allocate_device();

        if (!quickstart_input)
                return -ENOMEM;

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

        while (*ptr) {
                count++;
                set_bit(EV_KEY, quickstart_input->evbit);
                set_bit((*ptr)->id, quickstart_input->keybit);
                ptr = &((*ptr)->next);
        }

        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 (!quickstart_data.btn_lst) {
                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;

        printk(KERN_INFO "quickstart: 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);