Quelle  toshiba_haps.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Toshiba HDD Active Protection Sensor (HAPS) driver
 *
 * Copyright (C) 2014 Azael Avalos <coproscefalo@gmail.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

MODULE_AUTHOR("Azael Avalos <coproscefalo@gmail.com>");
MODULE_DESCRIPTION("Toshiba HDD Active Protection Sensor");
MODULE_LICENSE("GPL");

struct toshiba_haps_dev {
 struct acpi_device *acpi_dev;

 int protection_level;
};

static struct toshiba_haps_dev *toshiba_haps;

/* HAPS functions */
static int toshiba_haps_reset_protection(acpi_handle handle)
{
 acpi_status status;

 status = acpi_evaluate_object(handle, "RSSS", NULL, NULL);
 if (ACPI_FAILURE(status)) {
  pr_err("Unable to reset the HDD protection\n");
  return -EIO;
 }

 return 0;
}

static int toshiba_haps_protection_level(acpi_handle handle, int level)
{
 acpi_status status;

 status = acpi_execute_simple_method(handle, "PTLV", level);
 if (ACPI_FAILURE(status)) {
  pr_err("Error while setting the protection level\n");
  return -EIO;
 }

 pr_debug("HDD protection level set to: %d\n", level);

 return 0;
}

/* sysfs files */
static ssize_t protection_level_show(struct device *dev,
         struct device_attribute *attr, char *buf)
{
 struct toshiba_haps_dev *haps = dev_get_drvdata(dev);

 return sprintf(buf, "%i\n", haps->protection_level);
}

static ssize_t protection_level_store(struct device *dev,
          struct device_attribute *attr,
          const char *buf, size_t count)
{
 struct toshiba_haps_dev *haps = dev_get_drvdata(dev);
 int level;
 int ret;

 ret = kstrtoint(buf, 0, &level);
 if (ret)
  return ret;
 /*
  * Check for supported levels, which can be:
  * 0 - Disabled | 1 - Low | 2 - Medium | 3 - High
 */
 if (level < 0 || level > 3)
  return -EINVAL;

 /* Set the sensor level */
 ret = toshiba_haps_protection_level(haps->acpi_dev->handle, level);
 if (ret != 0)
  return ret;

 haps->protection_level = level;

 return count;
}
static DEVICE_ATTR_RW(protection_level);

static ssize_t reset_protection_store(struct device *dev,
          struct device_attribute *attr,
          const char *buf, size_t count)
{
 struct toshiba_haps_dev *haps = dev_get_drvdata(dev);
 int reset;
 int ret;

 ret = kstrtoint(buf, 0, &reset);
 if (ret)
  return ret;
 /* The only accepted value is 1 */
 if (reset != 1)
  return -EINVAL;

 /* Reset the protection interface */
 ret = toshiba_haps_reset_protection(haps->acpi_dev->handle);
 if (ret != 0)
  return ret;

 return count;
}
static DEVICE_ATTR_WO(reset_protection);

static struct attribute *haps_attributes[] = {
 &dev_attr_protection_level.attr,
 &dev_attr_reset_protection.attr,
 NULL,
};

static const struct attribute_group haps_attr_group = {
 .attrs = haps_attributes,
};

/*
 * ACPI stuff
 */
static void toshiba_haps_notify(struct acpi_device *device, u32 event)
{
 pr_debug("Received event: 0x%x\n", event);

 acpi_bus_generate_netlink_event(device->pnp.device_class,
     dev_name(&device->dev),
     event, 0);
}

static void toshiba_haps_remove(struct acpi_device *device)
{
 sysfs_remove_group(&device->dev.kobj, &haps_attr_group);

 if (toshiba_haps)
  toshiba_haps = NULL;
}

/* Helper function */
static int toshiba_haps_available(acpi_handle handle)
{
 acpi_status status;
 u64 hdd_present;

 /*
  * A non existent device as well as having (only)
  * Solid State Drives can cause the call to fail.
 */
 status = acpi_evaluate_integer(handle, "_STA", NULL, &hdd_present);
 if (ACPI_FAILURE(status)) {
  pr_err("ACPI call to query HDD protection failed\n");
  return 0;
 }

 if (!hdd_present) {
  pr_info("HDD protection not available or using SSD\n");
  return 0;
 }

 return 1;
}

static int toshiba_haps_add(struct acpi_device *acpi_dev)
{
 struct toshiba_haps_dev *haps;
 int ret;

 if (toshiba_haps)
  return -EBUSY;

 if (!toshiba_haps_available(acpi_dev->handle))
  return -ENODEV;

 pr_info("Toshiba HDD Active Protection Sensor device\n");

 haps = kzalloc(sizeof(struct toshiba_haps_dev), GFP_KERNEL);
 if (!haps)
  return -ENOMEM;

 haps->acpi_dev = acpi_dev;
 haps->protection_level = 2;
 acpi_dev->driver_data = haps;
 dev_set_drvdata(&acpi_dev->dev, haps);

 /* Set the protection level, currently at level 2 (Medium) */
 ret = toshiba_haps_protection_level(acpi_dev->handle, 2);
 if (ret != 0)
  return ret;

 ret = sysfs_create_group(&acpi_dev->dev.kobj, &haps_attr_group);
 if (ret)
  return ret;

 toshiba_haps = haps;

 return 0;
}

#ifdef CONFIG_PM_SLEEP
static int toshiba_haps_suspend(struct device *device)
{
 struct toshiba_haps_dev *haps;
 int ret;

 haps = acpi_driver_data(to_acpi_device(device));

 /* Deactivate the protection on suspend */
 ret = toshiba_haps_protection_level(haps->acpi_dev->handle, 0);

 return ret;
}

static int toshiba_haps_resume(struct device *device)
{
 struct toshiba_haps_dev *haps;
 int ret;

 haps = acpi_driver_data(to_acpi_device(device));

 /* Set the stored protection level */
 ret = toshiba_haps_protection_level(haps->acpi_dev->handle,
         haps->protection_level);

 /* Reset the protection on resume */
 ret = toshiba_haps_reset_protection(haps->acpi_dev->handle);
 if (ret != 0)
  return ret;

 return ret;
}
#endif

static SIMPLE_DEV_PM_OPS(toshiba_haps_pm,
    toshiba_haps_suspend, toshiba_haps_resume);

static const struct acpi_device_id haps_device_ids[] = {
 {"TOS620A", 0},
 {"", 0},
};
MODULE_DEVICE_TABLE(acpi, haps_device_ids);

static struct acpi_driver toshiba_haps_driver = {
 .name = "Toshiba HAPS",
 .ids = haps_device_ids,
 .flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,
 .ops = {
  .add =  toshiba_haps_add,
  .remove = toshiba_haps_remove,
  .notify = toshiba_haps_notify,
 },
 .drv.pm = &toshiba_haps_pm,
};

module_acpi_driver(toshiba_haps_driver);