/*
 * drivers/acpi/device_sysfs.c - ACPI device sysfs attributes and modalias.
 *
 * Copyright (C) 2015, Intel Corp.
 * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  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.
 *
 *  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.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/export.h>
#include <linux/nls.h>

#include "internal.h"

static ssize_t acpi_object_path(acpi_handle handle, char *buf)
{
        struct acpi_buffer path = {ACPI_ALLOCATE_BUFFER, NULL};
        int result;

        result = acpi_get_name(handle, ACPI_FULL_PATHNAME, &path);
        if (result)
                return result;

        result = sprintf(buf, "%s\n", (char *)path.pointer);
        kfree(path.pointer);
        return result;
}

struct acpi_data_node_attr {
        struct attribute attr;
        ssize_t (*show)(struct acpi_data_node *, char *);
        ssize_t (*store)(struct acpi_data_node *, const char *, size_t count);
};

#define DATA_NODE_ATTR(_name)                   \
        static struct acpi_data_node_attr data_node_##_name =   \
                __ATTR(_name, 0444, data_node_show_##_name, NULL)

static ssize_t data_node_show_path(struct acpi_data_node *dn, char *buf)
{
        return dn->handle ? acpi_object_path(dn->handle, buf) : 0;
}

DATA_NODE_ATTR(path);

static struct attribute *acpi_data_node_default_attrs[] = {
        &data_node_path.attr,
        NULL
};

#define to_data_node(k) container_of(k, struct acpi_data_node, kobj)
#define to_attr(a) container_of(a, struct acpi_data_node_attr, attr)

static ssize_t acpi_data_node_attr_show(struct kobject *kobj,
                                        struct attribute *attr, char *buf)
{
        struct acpi_data_node *dn = to_data_node(kobj);
        struct acpi_data_node_attr *dn_attr = to_attr(attr);

        return dn_attr->show ? dn_attr->show(dn, buf) : -ENXIO;
}

static const struct sysfs_ops acpi_data_node_sysfs_ops = {
        .show   = acpi_data_node_attr_show,
};

static void acpi_data_node_release(struct kobject *kobj)
{
        struct acpi_data_node *dn = to_data_node(kobj);

        complete(&dn->kobj_done);
}

static struct kobj_type acpi_data_node_ktype = {
        .sysfs_ops = &acpi_data_node_sysfs_ops,
        .default_attrs = acpi_data_node_default_attrs,
        .release = acpi_data_node_release,
};

static void acpi_expose_nondev_subnodes(struct kobject *kobj,
                                        struct acpi_device_data *data)
{
        struct list_head *list = &data->subnodes;
        struct acpi_data_node *dn;

        if (list_empty(list))
                return;

        list_for_each_entry(dn, list, sibling) {
                int ret;

                init_completion(&dn->kobj_done);
                ret = kobject_init_and_add(&dn->kobj, &acpi_data_node_ktype,
                                           kobj, "%s", dn->name);
                if (!ret)
                        acpi_expose_nondev_subnodes(&dn->kobj, &dn->data);
                else if (dn->handle)
                        acpi_handle_err(dn->handle, "Failed to expose (%d)\n", ret);
        }
}

static void acpi_hide_nondev_subnodes(struct acpi_device_data *data)
{
        struct list_head *list = &data->subnodes;
        struct acpi_data_node *dn;

        if (list_empty(list))
                return;

        list_for_each_entry_reverse(dn, list, sibling) {
                acpi_hide_nondev_subnodes(&dn->data);
                kobject_put(&dn->kobj);
        }
}

/**
 * create_pnp_modalias - Create hid/cid(s) string for modalias and uevent
 * @acpi_dev: ACPI device object.
 * @modalias: Buffer to print into.
 * @size: Size of the buffer.
 *
 * Creates hid/cid(s) string needed for modalias and uevent
 * e.g. on a device with hid:IBM0001 and cid:ACPI0001 you get:
 * char *modalias: "acpi:IBM0001:ACPI0001"
 * Return: 0: no _HID and no _CID
 *         -EINVAL: output error
 *         -ENOMEM: output is truncated
 */
static int create_pnp_modalias(struct acpi_device *acpi_dev, char *modalias,
                               int size)
{
        int len;
        int count;
        struct acpi_hardware_id *id;

        /* Avoid unnecessarily loading modules for non present devices. */
        if (!acpi_device_is_present(acpi_dev))
                return 0;

        /*
         * Since we skip ACPI_DT_NAMESPACE_HID from the modalias below, 0 should
         * be returned if ACPI_DT_NAMESPACE_HID is the only ACPI/PNP ID in the
         * device's list.
         */
        count = 0;
        list_for_each_entry(id, &acpi_dev->pnp.ids, list)
                if (strcmp(id->id, ACPI_DT_NAMESPACE_HID))
                        count++;

        if (!count)
                return 0;

        len = snprintf(modalias, size, "acpi:");
        if (len <= 0)
                return len;

        size -= len;

        list_for_each_entry(id, &acpi_dev->pnp.ids, list) {
                if (!strcmp(id->id, ACPI_DT_NAMESPACE_HID))
                        continue;

                count = snprintf(&modalias[len], size, "%s:", id->id);
                if (count < 0)
                        return -EINVAL;

                if (count >= size)
                        return -ENOMEM;

                len += count;
                size -= count;
        }
        modalias[len] = '\0';
        return len;
}

/**
 * create_of_modalias - Creates DT compatible string for modalias and uevent
 * @acpi_dev: ACPI device object.
 * @modalias: Buffer to print into.
 * @size: Size of the buffer.
 *
 * Expose DT compatible modalias as of:NnameTCcompatible.  This function should
 * only be called for devices having ACPI_DT_NAMESPACE_HID in their list of
 * ACPI/PNP IDs.
 */
static int create_of_modalias(struct acpi_device *acpi_dev, char *modalias,
                              int size)
{
        struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
        const union acpi_object *of_compatible, *obj;
        acpi_status status;
        int len, count;
        int i, nval;
        char *c;

        status = acpi_get_name(acpi_dev->handle, ACPI_SINGLE_NAME, &buf);
        if (ACPI_FAILURE(status))
                return -ENODEV;

        /* DT strings are all in lower case */
        for (c = buf.pointer; *c != '\0'; c++)
                *c = tolower(*c);

        len = snprintf(modalias, size, "of:N%sT", (char *)buf.pointer);
        ACPI_FREE(buf.pointer);

        if (len <= 0)
                return len;

        of_compatible = acpi_dev->data.of_compatible;
        if (of_compatible->type == ACPI_TYPE_PACKAGE) {
                nval = of_compatible->package.count;
                obj = of_compatible->package.elements;
        } else { /* Must be ACPI_TYPE_STRING. */
                nval = 1;
                obj = of_compatible;
        }
        for (i = 0; i < nval; i++, obj++) {
                count = snprintf(&modalias[len], size, "C%s",
                                 obj->string.pointer);
                if (count < 0)
                        return -EINVAL;

                if (count >= size)
                        return -ENOMEM;

                len += count;
                size -= count;
        }
        modalias[len] = '\0';
        return len;
}

int __acpi_device_uevent_modalias(struct acpi_device *adev,
                                  struct kobj_uevent_env *env)
{
        int len;

        if (!adev)
                return -ENODEV;

        if (list_empty(&adev->pnp.ids))
                return 0;

        if (add_uevent_var(env, "MODALIAS="))
                return -ENOMEM;

        if (adev->data.of_compatible)
                len = create_of_modalias(adev, &env->buf[env->buflen - 1],
                                         sizeof(env->buf) - env->buflen);
        else
                len = create_pnp_modalias(adev, &env->buf[env->buflen - 1],
                                          sizeof(env->buf) - env->buflen);
        if (len < 0)
                return len;

        env->buflen += len;

        return 0;
}

/**
 * acpi_device_uevent_modalias - uevent modalias for ACPI-enumerated devices.
 * @dev: Struct device to get ACPI device node.
 * @env: Environment variables of the kobject uevent.
 *
 * Create the uevent modalias field for ACPI-enumerated devices.
 *
 * Because other buses do not support ACPI HIDs & CIDs, e.g. for a device with
 * hid:IBM0001 and cid:ACPI0001 you get: "acpi:IBM0001:ACPI0001".
 */
int acpi_device_uevent_modalias(struct device *dev, struct kobj_uevent_env *env)
{
        return __acpi_device_uevent_modalias(acpi_companion_match(dev), env);
}
EXPORT_SYMBOL_GPL(acpi_device_uevent_modalias);

static int __acpi_device_modalias(struct acpi_device *adev, char *buf, int size)
{
        int len, count;

        if (!adev)
                return -ENODEV;

        if (list_empty(&adev->pnp.ids))
                return 0;

        len = create_pnp_modalias(adev, buf, size - 1);
        if (len < 0) {
                return len;
        } else if (len > 0) {
                buf[len++] = '\n';
                size -= len;
        }
        if (!adev->data.of_compatible)
                return len;

        count = create_of_modalias(adev, buf + len, size - 1);
        if (count < 0) {
                return count;
        } else if (count > 0) {
                len += count;
                buf[len++] = '\n';
        }

        return len;
}

/**
 * acpi_device_modalias - modalias sysfs attribute for ACPI-enumerated devices.
 * @dev: Struct device to get ACPI device node.
 * @buf: The buffer to save pnp_modalias and of_modalias.
 * @size: Size of buffer.
 *
 * Create the modalias sysfs attribute for ACPI-enumerated devices.
 *
 * Because other buses do not support ACPI HIDs & CIDs, e.g. for a device with
 * hid:IBM0001 and cid:ACPI0001 you get: "acpi:IBM0001:ACPI0001".
 */
int acpi_device_modalias(struct device *dev, char *buf, int size)
{
        return __acpi_device_modalias(acpi_companion_match(dev), buf, size);
}
EXPORT_SYMBOL_GPL(acpi_device_modalias);

static ssize_t
modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        return __acpi_device_modalias(to_acpi_device(dev), buf, 1024);
}
static DEVICE_ATTR_RO(modalias);

static ssize_t real_power_state_show(struct device *dev,
                                     struct device_attribute *attr, char *buf)
{
        struct acpi_device *adev = to_acpi_device(dev);
        int state;
        int ret;

        ret = acpi_device_get_power(adev, &state);
        if (ret)
                return ret;

        return sprintf(buf, "%s\n", acpi_power_state_string(state));
}

static DEVICE_ATTR_RO(real_power_state);

static ssize_t power_state_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct acpi_device *adev = to_acpi_device(dev);

        return sprintf(buf, "%s\n", acpi_power_state_string(adev->power.state));
}

static DEVICE_ATTR_RO(power_state);

static ssize_t
eject_store(struct device *d, struct device_attribute *attr,
            const char *buf, size_t count)
{
        struct acpi_device *acpi_device = to_acpi_device(d);
        acpi_object_type not_used;
        acpi_status status;

        if (!count || buf[0] != '1')
                return -EINVAL;

        if ((!acpi_device->handler || !acpi_device->handler->hotplug.enabled)
            && !acpi_device->driver)
                return -ENODEV;

        status = acpi_get_type(acpi_device->handle, &not_used);
        if (ACPI_FAILURE(status) || !acpi_device->flags.ejectable)
                return -ENODEV;

        acpi_dev_get(acpi_device);
        status = acpi_hotplug_schedule(acpi_device, ACPI_OST_EC_OSPM_EJECT);
        if (ACPI_SUCCESS(status))
                return count;

        acpi_dev_put(acpi_device);
        acpi_evaluate_ost(acpi_device->handle, ACPI_OST_EC_OSPM_EJECT,
                          ACPI_OST_SC_NON_SPECIFIC_FAILURE, NULL);
        return status == AE_NO_MEMORY ? -ENOMEM : -EAGAIN;
}

static DEVICE_ATTR_WO(eject);

static ssize_t
hid_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct acpi_device *acpi_dev = to_acpi_device(dev);

        return sprintf(buf, "%s\n", acpi_device_hid(acpi_dev));
}
static DEVICE_ATTR_RO(hid);

static ssize_t uid_show(struct device *dev,
                        struct device_attribute *attr, char *buf)
{
        struct acpi_device *acpi_dev = to_acpi_device(dev);

        return sprintf(buf, "%s\n", acpi_dev->pnp.unique_id);
}
static DEVICE_ATTR_RO(uid);

static ssize_t adr_show(struct device *dev,
                        struct device_attribute *attr, char *buf)
{
        struct acpi_device *acpi_dev = to_acpi_device(dev);

        if (acpi_dev->pnp.bus_address > U32_MAX)
                return sprintf(buf, "0x%016llx\n", acpi_dev->pnp.bus_address);
        else
                return sprintf(buf, "0x%08llx\n", acpi_dev->pnp.bus_address);
}
static DEVICE_ATTR_RO(adr);

static ssize_t path_show(struct device *dev,
                         struct device_attribute *attr, char *buf)
{
        struct acpi_device *acpi_dev = to_acpi_device(dev);

        return acpi_object_path(acpi_dev->handle, buf);
}
static DEVICE_ATTR_RO(path);

/* sysfs file that shows description text from the ACPI _STR method */
static ssize_t description_show(struct device *dev,
                                struct device_attribute *attr,
                                char *buf)
{
        struct acpi_device *acpi_dev = to_acpi_device(dev);
        int result;

        if (acpi_dev->pnp.str_obj == NULL)
                return 0;

        /*
         * The _STR object contains a Unicode identifier for a device.
         * We need to convert to utf-8 so it can be displayed.
         */
        result = utf16s_to_utf8s(
                (wchar_t *)acpi_dev->pnp.str_obj->buffer.pointer,
                acpi_dev->pnp.str_obj->buffer.length,
                UTF16_LITTLE_ENDIAN, buf,
                PAGE_SIZE - 1);

        buf[result++] = '\n';

        return result;
}
static DEVICE_ATTR_RO(description);

static ssize_t
sun_show(struct device *dev, struct device_attribute *attr,
         char *buf)
{
        struct acpi_device *acpi_dev = to_acpi_device(dev);
        acpi_status status;
        unsigned long long sun;

        status = acpi_evaluate_integer(acpi_dev->handle, "_SUN", NULL, &sun);
        if (ACPI_FAILURE(status))
                return -EIO;

        return sprintf(buf, "%llu\n", sun);
}
static DEVICE_ATTR_RO(sun);

static ssize_t
hrv_show(struct device *dev, struct device_attribute *attr,
         char *buf)
{
        struct acpi_device *acpi_dev = to_acpi_device(dev);
        acpi_status status;
        unsigned long long hrv;

        status = acpi_evaluate_integer(acpi_dev->handle, "_HRV", NULL, &hrv);
        if (ACPI_FAILURE(status))
                return -EIO;

        return sprintf(buf, "%llu\n", hrv);
}
static DEVICE_ATTR_RO(hrv);

static ssize_t status_show(struct device *dev, struct device_attribute *attr,
                                char *buf)
{
        struct acpi_device *acpi_dev = to_acpi_device(dev);
        acpi_status status;
        unsigned long long sta;

        status = acpi_evaluate_integer(acpi_dev->handle, "_STA", NULL, &sta);
        if (ACPI_FAILURE(status))
                return -EIO;

        return sprintf(buf, "%llu\n", sta);
}
static DEVICE_ATTR_RO(status);

/**
 * acpi_device_setup_files - Create sysfs attributes of an ACPI device.
 * @dev: ACPI device object.
 */
int acpi_device_setup_files(struct acpi_device *dev)
{
        struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
        acpi_status status;
        int result = 0;

        /*
         * Devices gotten from FADT don't have a "path" attribute
         */
        if (dev->handle) {
                result = device_create_file(&dev->dev, &dev_attr_path);
                if (result)
                        goto end;
        }

        if (!list_empty(&dev->pnp.ids)) {
                result = device_create_file(&dev->dev, &dev_attr_hid);
                if (result)
                        goto end;

                result = device_create_file(&dev->dev, &dev_attr_modalias);
                if (result)
                        goto end;
        }

        /*
         * If device has _STR, 'description' file is created
         */
        if (acpi_has_method(dev->handle, "_STR")) {
                status = acpi_evaluate_object(dev->handle, "_STR",
                                        NULL, &buffer);
                if (ACPI_FAILURE(status))
                        buffer.pointer = NULL;
                dev->pnp.str_obj = buffer.pointer;
                result = device_create_file(&dev->dev, &dev_attr_description);
                if (result)
                        goto end;
        }

        if (dev->pnp.type.bus_address)
                result = device_create_file(&dev->dev, &dev_attr_adr);
        if (dev->pnp.unique_id)
                result = device_create_file(&dev->dev, &dev_attr_uid);

        if (acpi_has_method(dev->handle, "_SUN")) {
                result = device_create_file(&dev->dev, &dev_attr_sun);
                if (result)
                        goto end;
        }

        if (acpi_has_method(dev->handle, "_HRV")) {
                result = device_create_file(&dev->dev, &dev_attr_hrv);
                if (result)
                        goto end;
        }

        if (acpi_has_method(dev->handle, "_STA")) {
                result = device_create_file(&dev->dev, &dev_attr_status);
                if (result)
                        goto end;
        }

        /*
         * If device has _EJ0, 'eject' file is created that is used to trigger
         * hot-removal function from userland.
         */
        if (acpi_has_method(dev->handle, "_EJ0")) {
                result = device_create_file(&dev->dev, &dev_attr_eject);
                if (result)
                        return result;
        }

        if (dev->flags.power_manageable) {
                result = device_create_file(&dev->dev, &dev_attr_power_state);
                if (result)
                        return result;

                if (dev->power.flags.power_resources)
                        result = device_create_file(&dev->dev,
                                                    &dev_attr_real_power_state);
        }

        acpi_expose_nondev_subnodes(&dev->dev.kobj, &dev->data);

end:
        return result;
}

/**
 * acpi_device_remove_files - Remove sysfs attributes of an ACPI device.
 * @dev: ACPI device object.
 */
void acpi_device_remove_files(struct acpi_device *dev)
{
        acpi_hide_nondev_subnodes(&dev->data);

        if (dev->flags.power_manageable) {
                device_remove_file(&dev->dev, &dev_attr_power_state);
                if (dev->power.flags.power_resources)
                        device_remove_file(&dev->dev,
                                           &dev_attr_real_power_state);
        }

        /*
         * If device has _STR, remove 'description' file
         */
        if (acpi_has_method(dev->handle, "_STR")) {
                kfree(dev->pnp.str_obj);
                device_remove_file(&dev->dev, &dev_attr_description);
        }
        /*
         * If device has _EJ0, remove 'eject' file.
         */
        if (acpi_has_method(dev->handle, "_EJ0"))
                device_remove_file(&dev->dev, &dev_attr_eject);

        if (acpi_has_method(dev->handle, "_SUN"))
                device_remove_file(&dev->dev, &dev_attr_sun);

        if (acpi_has_method(dev->handle, "_HRV"))
                device_remove_file(&dev->dev, &dev_attr_hrv);

        if (dev->pnp.unique_id)
                device_remove_file(&dev->dev, &dev_attr_uid);
        if (dev->pnp.type.bus_address)
                device_remove_file(&dev->dev, &dev_attr_adr);
        device_remove_file(&dev->dev, &dev_attr_modalias);
        device_remove_file(&dev->dev, &dev_attr_hid);
        if (acpi_has_method(dev->handle, "_STA"))
                device_remove_file(&dev->dev, &dev_attr_status);
        if (dev->handle)
                device_remove_file(&dev->dev, &dev_attr_path);
}