/*
 *  intel_menlow.c - Intel menlow Driver for thermal management extension
 *
 *  Copyright (C) 2008 Intel Corp
 *  Copyright (C) 2008 Sujith Thomas <sujith.thomas@intel.com>
 *  Copyright (C) 2008 Zhang Rui <rui.zhang@intel.com>
 *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  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; version 2 of the License.
 *
 *  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.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This driver creates the sys I/F for programming the sensors.
 *  It also implements the driver for intel menlow memory controller (hardware
 *  id is INT0002) which makes use of the platform specific ACPI methods
 *  to get/set bandwidth.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/pm.h>
#include <linux/thermal.h>
#include <linux/acpi.h>

MODULE_AUTHOR("Thomas Sujith");
MODULE_AUTHOR("Zhang Rui");
MODULE_DESCRIPTION("Intel Menlow platform specific driver");
MODULE_LICENSE("GPL");

/*
 * Memory controller device control
 */

#define MEMORY_GET_BANDWIDTH "GTHS"
#define MEMORY_SET_BANDWIDTH "STHS"
#define MEMORY_ARG_CUR_BANDWIDTH 1
#define MEMORY_ARG_MAX_BANDWIDTH 0

static void intel_menlow_unregister_sensor(void);

/*
 * GTHS returning 'n' would mean that [0,n-1] states are supported
 * In that case max_cstate would be n-1
 * GTHS returning '0' would mean that no bandwidth control states are supported
 */
static int memory_get_max_bandwidth(struct thermal_cooling_device *cdev,
                                    unsigned long *max_state)
{
        struct acpi_device *device = cdev->devdata;
        acpi_handle handle = device->handle;
        unsigned long long value;
        struct acpi_object_list arg_list;
        union acpi_object arg;
        acpi_status status = AE_OK;

        arg_list.count = 1;
        arg_list.pointer = &arg;
        arg.type = ACPI_TYPE_INTEGER;
        arg.integer.value = MEMORY_ARG_MAX_BANDWIDTH;
        status = acpi_evaluate_integer(handle, MEMORY_GET_BANDWIDTH,
                                       &arg_list, &value);
        if (ACPI_FAILURE(status))
                return -EFAULT;

        if (!value)
                return -EINVAL;

        *max_state = value - 1;
        return 0;
}

static int memory_get_cur_bandwidth(struct thermal_cooling_device *cdev,
                                    unsigned long *value)
{
        struct acpi_device *device = cdev->devdata;
        acpi_handle handle = device->handle;
        unsigned long long result;
        struct acpi_object_list arg_list;
        union acpi_object arg;
        acpi_status status = AE_OK;

        arg_list.count = 1;
        arg_list.pointer = &arg;
        arg.type = ACPI_TYPE_INTEGER;
        arg.integer.value = MEMORY_ARG_CUR_BANDWIDTH;
        status = acpi_evaluate_integer(handle, MEMORY_GET_BANDWIDTH,
                                       &arg_list, &result);
        if (ACPI_FAILURE(status))
                return -EFAULT;

        *value = result;
        return 0;
}

static int memory_set_cur_bandwidth(struct thermal_cooling_device *cdev,
                                    unsigned long state)
{
        struct acpi_device *device = cdev->devdata;
        acpi_handle handle = device->handle;
        struct acpi_object_list arg_list;
        union acpi_object arg;
        acpi_status status;
        unsigned long long temp;
        unsigned long max_state;

        if (memory_get_max_bandwidth(cdev, &max_state))
                return -EFAULT;

        if (state > max_state)
                return -EINVAL;

        arg_list.count = 1;
        arg_list.pointer = &arg;
        arg.type = ACPI_TYPE_INTEGER;
        arg.integer.value = state;

        status =
            acpi_evaluate_integer(handle, MEMORY_SET_BANDWIDTH, &arg_list,
                                  &temp);

        pr_info("Bandwidth value was %ld: status is %d\n", state, status);
        if (ACPI_FAILURE(status))
                return -EFAULT;

        return 0;
}

static const struct thermal_cooling_device_ops memory_cooling_ops = {
        .get_max_state = memory_get_max_bandwidth,
        .get_cur_state = memory_get_cur_bandwidth,
        .set_cur_state = memory_set_cur_bandwidth,
};

/*
 * Memory Device Management
 */
static int intel_menlow_memory_add(struct acpi_device *device)
{
        int result = -ENODEV;
        struct thermal_cooling_device *cdev;

        if (!device)
                return -EINVAL;

        if (!acpi_has_method(device->handle, MEMORY_GET_BANDWIDTH))
                goto end;

        if (!acpi_has_method(device->handle, MEMORY_SET_BANDWIDTH))
                goto end;

        cdev = thermal_cooling_device_register("Memory controller", device,
                                               &memory_cooling_ops);
        if (IS_ERR(cdev)) {
                result = PTR_ERR(cdev);
                goto end;
        }

        device->driver_data = cdev;
        result = sysfs_create_link(&device->dev.kobj,
                                &cdev->device.kobj, "thermal_cooling");
        if (result)
                goto unregister;

        result = sysfs_create_link(&cdev->device.kobj,
                                &device->dev.kobj, "device");
        if (result) {
                sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
                goto unregister;
        }

 end:
        return result;

 unregister:
        thermal_cooling_device_unregister(cdev);
        return result;

}

static int intel_menlow_memory_remove(struct acpi_device *device)
{
        struct thermal_cooling_device *cdev = acpi_driver_data(device);

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

        sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
        sysfs_remove_link(&cdev->device.kobj, "device");
        thermal_cooling_device_unregister(cdev);

        return 0;
}

static const struct acpi_device_id intel_menlow_memory_ids[] = {
        {"INT0002", 0},
        {"", 0},
};

static struct acpi_driver intel_menlow_memory_driver = {
        .name = "intel_menlow_thermal_control",
        .ids = intel_menlow_memory_ids,
        .ops = {
                .add = intel_menlow_memory_add,
                .remove = intel_menlow_memory_remove,
                },
};

/*
 * Sensor control on menlow platform
 */

#define THERMAL_AUX0 0
#define THERMAL_AUX1 1
#define GET_AUX0 "GAX0"
#define GET_AUX1 "GAX1"
#define SET_AUX0 "SAX0"
#define SET_AUX1 "SAX1"

struct intel_menlow_attribute {
        struct device_attribute attr;
        struct device *device;
        acpi_handle handle;
        struct list_head node;
};

static LIST_HEAD(intel_menlow_attr_list);
static DEFINE_MUTEX(intel_menlow_attr_lock);

/*
 * sensor_get_auxtrip - get the current auxtrip value from sensor
 * @name: Thermalzone name
 * @auxtype : AUX0/AUX1
 * @buf: syfs buffer
 */
static int sensor_get_auxtrip(acpi_handle handle, int index,
                                                        unsigned long long *value)
{
        acpi_status status;

        if ((index != 0 && index != 1) || !value)
                return -EINVAL;

        status = acpi_evaluate_integer(handle, index ? GET_AUX1 : GET_AUX0,
                                       NULL, value);
        if (ACPI_FAILURE(status))
                return -EIO;

        return 0;
}

/*
 * sensor_set_auxtrip - set the new auxtrip value to sensor
 * @name: Thermalzone name
 * @auxtype : AUX0/AUX1
 * @buf: syfs buffer
 */
static int sensor_set_auxtrip(acpi_handle handle, int index, int value)
{
        acpi_status status;
        union acpi_object arg = {
                ACPI_TYPE_INTEGER
        };
        struct acpi_object_list args = {
                1, &arg
        };
        unsigned long long temp;

        if (index != 0 && index != 1)
                return -EINVAL;

        status = acpi_evaluate_integer(handle, index ? GET_AUX0 : GET_AUX1,
                                       NULL, &temp);
        if (ACPI_FAILURE(status))
                return -EIO;
        if ((index && value < temp) || (!index && value > temp))
                return -EINVAL;

        arg.integer.value = value;
        status = acpi_evaluate_integer(handle, index ? SET_AUX1 : SET_AUX0,
                                       &args, &temp);
        if (ACPI_FAILURE(status))
                return -EIO;

        /* do we need to check the return value of SAX0/SAX1 ? */

        return 0;
}

#define to_intel_menlow_attr(_attr)     \
        container_of(_attr, struct intel_menlow_attribute, attr)

static ssize_t aux_show(struct device *dev, struct device_attribute *dev_attr,
                        char *buf, int idx)
{
        struct intel_menlow_attribute *attr = to_intel_menlow_attr(dev_attr);
        unsigned long long value;
        int result;

        result = sensor_get_auxtrip(attr->handle, idx, &value);

        return result ? result : sprintf(buf, "%lu", DECI_KELVIN_TO_CELSIUS(value));
}

static ssize_t aux0_show(struct device *dev,
                         struct device_attribute *dev_attr, char *buf)
{
        return aux_show(dev, dev_attr, buf, 0);
}

static ssize_t aux1_show(struct device *dev,
                         struct device_attribute *dev_attr, char *buf)
{
        return aux_show(dev, dev_attr, buf, 1);
}

static ssize_t aux_store(struct device *dev, struct device_attribute *dev_attr,
                         const char *buf, size_t count, int idx)
{
        struct intel_menlow_attribute *attr = to_intel_menlow_attr(dev_attr);
        int value;
        int result;

        /*Sanity check; should be a positive integer */
        if (!sscanf(buf, "%d", &value))
                return -EINVAL;

        if (value < 0)
                return -EINVAL;

        result = sensor_set_auxtrip(attr->handle, idx, 
                                    CELSIUS_TO_DECI_KELVIN(value));
        return result ? result : count;
}

static ssize_t aux0_store(struct device *dev,
                          struct device_attribute *dev_attr,
                          const char *buf, size_t count)
{
        return aux_store(dev, dev_attr, buf, count, 0);
}

static ssize_t aux1_store(struct device *dev,
                          struct device_attribute *dev_attr,
                          const char *buf, size_t count)
{
        return aux_store(dev, dev_attr, buf, count, 1);
}

/* BIOS can enable/disable the thermal user application in dabney platform */
#define BIOS_ENABLED "\\_TZ.GSTS"
static ssize_t bios_enabled_show(struct device *dev,
                                 struct device_attribute *attr, char *buf)
{
        acpi_status status;
        unsigned long long bios_enabled;

        status = acpi_evaluate_integer(NULL, BIOS_ENABLED, NULL, &bios_enabled);
        if (ACPI_FAILURE(status))
                return -ENODEV;

        return sprintf(buf, "%s\n", bios_enabled ? "enabled" : "disabled");
}

static int intel_menlow_add_one_attribute(char *name, umode_t mode, void *show,
                                          void *store, struct device *dev,
                                          acpi_handle handle)
{
        struct intel_menlow_attribute *attr;
        int result;

        attr = kzalloc(sizeof(struct intel_menlow_attribute), GFP_KERNEL);
        if (!attr)
                return -ENOMEM;

        sysfs_attr_init(&attr->attr.attr); /* That is consistent naming :D */
        attr->attr.attr.name = name;
        attr->attr.attr.mode = mode;
        attr->attr.show = show;
        attr->attr.store = store;
        attr->device = dev;
        attr->handle = handle;

        result = device_create_file(dev, &attr->attr);
        if (result) {
                kfree(attr);
                return result;
        }

        mutex_lock(&intel_menlow_attr_lock);
        list_add_tail(&attr->node, &intel_menlow_attr_list);
        mutex_unlock(&intel_menlow_attr_lock);

        return 0;
}

static acpi_status intel_menlow_register_sensor(acpi_handle handle, u32 lvl,
                                                void *context, void **rv)
{
        acpi_status status;
        acpi_handle dummy;
        struct thermal_zone_device *thermal;
        int result;

        result = acpi_bus_get_private_data(handle, (void **)&thermal);
        if (result)
                return 0;

        /* _TZ must have the AUX0/1 methods */
        status = acpi_get_handle(handle, GET_AUX0, &dummy);
        if (ACPI_FAILURE(status))
                return (status == AE_NOT_FOUND) ? AE_OK : status;

        status = acpi_get_handle(handle, SET_AUX0, &dummy);
        if (ACPI_FAILURE(status))
                return (status == AE_NOT_FOUND) ? AE_OK : status;

        result = intel_menlow_add_one_attribute("aux0", 0644,
                                                aux0_show, aux0_store,
                                                &thermal->device, handle);
        if (result)
                return AE_ERROR;

        status = acpi_get_handle(handle, GET_AUX1, &dummy);
        if (ACPI_FAILURE(status))
                goto aux1_not_found;

        status = acpi_get_handle(handle, SET_AUX1, &dummy);
        if (ACPI_FAILURE(status))
                goto aux1_not_found;

        result = intel_menlow_add_one_attribute("aux1", 0644,
                                                aux1_show, aux1_store,
                                                &thermal->device, handle);
        if (result) {
                intel_menlow_unregister_sensor();
                return AE_ERROR;
        }

        /*
         * create the "dabney_enabled" attribute which means the user app
         * should be loaded or not
         */

        result = intel_menlow_add_one_attribute("bios_enabled", 0444,
                                                bios_enabled_show, NULL,
                                                &thermal->device, handle);
        if (result) {
                intel_menlow_unregister_sensor();
                return AE_ERROR;
        }

        return AE_OK;

 aux1_not_found:
        if (status == AE_NOT_FOUND)
                return AE_OK;

        intel_menlow_unregister_sensor();
        return status;
}

static void intel_menlow_unregister_sensor(void)
{
        struct intel_menlow_attribute *pos, *next;

        mutex_lock(&intel_menlow_attr_lock);
        list_for_each_entry_safe(pos, next, &intel_menlow_attr_list, node) {
                list_del(&pos->node);
                device_remove_file(pos->device, &pos->attr);
                kfree(pos);
        }
        mutex_unlock(&intel_menlow_attr_lock);

        return;
}

static int __init intel_menlow_module_init(void)
{
        int result = -ENODEV;
        acpi_status status;
        unsigned long long enable;

        if (acpi_disabled)
                return result;

        /* Looking for the \_TZ.GSTS method */
        status = acpi_evaluate_integer(NULL, BIOS_ENABLED, NULL, &enable);
        if (ACPI_FAILURE(status) || !enable)
                return -ENODEV;

        /* Looking for ACPI device MEM0 with hardware id INT0002 */
        result = acpi_bus_register_driver(&intel_menlow_memory_driver);
        if (result)
                return result;

        /* Looking for sensors in each ACPI thermal zone */
        status = acpi_walk_namespace(ACPI_TYPE_THERMAL, ACPI_ROOT_OBJECT,
                                     ACPI_UINT32_MAX,
                                     intel_menlow_register_sensor, NULL, NULL, NULL);
        if (ACPI_FAILURE(status)) {
                acpi_bus_unregister_driver(&intel_menlow_memory_driver);
                return -ENODEV;
        }

        return 0;
}

static void __exit intel_menlow_module_exit(void)
{
        acpi_bus_unregister_driver(&intel_menlow_memory_driver);
        intel_menlow_unregister_sensor();
}

module_init(intel_menlow_module_init);
module_exit(intel_menlow_module_exit);