#include <linux/libata.h>
  #include <linux/cdrom.h>
  #include <linux/pm_runtime.h>
  #include <linux/module.h>
  #include <linux/pm_qos.h>
  #include <scsi/scsi_device.h>
  
  #include "libata.h"
  
  static int zpodd_poweroff_delay = 30; /* 30 seconds for power off delay */
  module_param(zpodd_poweroff_delay, int, 0644);
  MODULE_PARM_DESC(zpodd_poweroff_delay, "Poweroff delay for ZPODD in seconds");
  
  enum odd_mech_type {
  	ODD_MECH_TYPE_SLOT,
  	ODD_MECH_TYPE_DRAWER,
  	ODD_MECH_TYPE_UNSUPPORTED,
  };
  
  struct zpodd {
  	enum odd_mech_type	mech_type; /* init during probe, RO afterwards */
  	struct ata_device	*dev;
  
  	/* The following fields are synchronized by PM core. */
  	bool			from_notify; /* resumed as a result of
  					      * acpi wake notification */
  	bool			zp_ready; /* ZP ready state */
  	unsigned long		last_ready; /* last ZP ready timestamp */
  	bool			zp_sampled; /* ZP ready state sampled */
  	bool			powered_off; /* ODD is powered off
  					      *	during suspend */
  };
  
  static int eject_tray(struct ata_device *dev)
  {
  	struct ata_taskfile tf;
  	const char cdb[] = {  GPCMD_START_STOP_UNIT,
  		0, 0, 0,
  		0x02,     /* LoEj */
  		0, 0, 0, 0, 0, 0, 0,
  	};
  
  	ata_tf_init(dev, &tf);
  	tf.flags = ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
  	tf.command = ATA_CMD_PACKET;
  	tf.protocol = ATAPI_PROT_NODATA;
  
  	return ata_exec_internal(dev, &tf, cdb, DMA_NONE, NULL, 0, 0);
  }
  
  /* Per the spec, only slot type and drawer type ODD can be supported */
  static enum odd_mech_type zpodd_get_mech_type(struct ata_device *dev)
  {
  	char buf[16];
  	unsigned int ret;
  	struct rm_feature_desc *desc = (void *)(buf + 8);
  	struct ata_taskfile tf;
  	char cdb[] = {  GPCMD_GET_CONFIGURATION,
  			2,      /* only 1 feature descriptor requested */
  			0, 3,   /* 3, removable medium feature */
  			0, 0, 0,/* reserved */
  			0, sizeof(buf),
  			0, 0, 0,
  	};
  
  	ata_tf_init(dev, &tf);
  	tf.flags = ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
  	tf.command = ATA_CMD_PACKET;
  	tf.protocol = ATAPI_PROT_PIO;
  	tf.lbam = sizeof(buf);
  
  	ret = ata_exec_internal(dev, &tf, cdb, DMA_FROM_DEVICE,
  				buf, sizeof(buf), 0);
  	if (ret)
  		return ODD_MECH_TYPE_UNSUPPORTED;
  
  	if (be16_to_cpu(desc->feature_code) != 3)
  		return ODD_MECH_TYPE_UNSUPPORTED;
  
  	if (desc->mech_type == 0 && desc->load == 0 && desc->eject == 1)
  		return ODD_MECH_TYPE_SLOT;
  	else if (desc->mech_type == 1 && desc->load == 0 && desc->eject == 1)
  		return ODD_MECH_TYPE_DRAWER;
  	else
  		return ODD_MECH_TYPE_UNSUPPORTED;
  }
  
  /* Test if ODD is zero power ready by sense code */
  static bool zpready(struct ata_device *dev)
  {
  	u8 sense_key, *sense_buf;
  	unsigned int ret, asc, ascq, add_len;
  	struct zpodd *zpodd = dev->zpodd;
  
  	ret = atapi_eh_tur(dev, &sense_key);
  
  	if (!ret || sense_key != NOT_READY)
  		return false;
  
  	sense_buf = dev->link->ap->sector_buf;
  	ret = atapi_eh_request_sense(dev, sense_buf, sense_key);
  	if (ret)
  		return false;
  
  	/* sense valid */
  	if ((sense_buf[0] & 0x7f) != 0x70)
  		return false;
  
  	add_len = sense_buf[7];
  	/* has asc and ascq */
  	if (add_len < 6)
  		return false;
  
  	asc = sense_buf[12];
  	ascq = sense_buf[13];
  
  	if (zpodd->mech_type == ODD_MECH_TYPE_SLOT)
  		/* no media inside */
  		return asc == 0x3a;
  	else
  		/* no media inside and door closed */
  		return asc == 0x3a && ascq == 0x01;
  }
  
  /*
   * Update the zpodd->zp_ready field. This field will only be set
   * if the ODD has stayed in ZP ready state for zpodd_poweroff_delay
   * time, and will be used to decide if power off is allowed. If it
   * is set, it will be cleared during resume from powered off state.
   */
  void zpodd_on_suspend(struct ata_device *dev)
  {
  	struct zpodd *zpodd = dev->zpodd;
  	unsigned long expires;
  
  	if (!zpready(dev)) {
  		zpodd->zp_sampled = false;
  		zpodd->zp_ready = false;
  		return;
  	}
  
  	if (!zpodd->zp_sampled) {
  		zpodd->zp_sampled = true;
  		zpodd->last_ready = jiffies;
  		return;
  	}
  
  	expires = zpodd->last_ready +
  		  msecs_to_jiffies(zpodd_poweroff_delay * 1000);
  	if (time_before(jiffies, expires))
  		return;
  
  	zpodd->zp_ready = true;
  }
  
  bool zpodd_zpready(struct ata_device *dev)
  {
  	struct zpodd *zpodd = dev->zpodd;
  	return zpodd->zp_ready;
  }
  
  /*
   * Enable runtime wake capability through ACPI and set the powered_off flag,
   * this flag will be used during resume to decide what operations are needed
   * to take.
   *
   * Also, media poll needs to be silenced, so that it doesn't bring the ODD
   * back to full power state every few seconds.
   */
  void zpodd_enable_run_wake(struct ata_device *dev)
  {
  	struct zpodd *zpodd = dev->zpodd;
  
  	sdev_disable_disk_events(dev->sdev);
  
  	zpodd->powered_off = true;
  	device_set_run_wake(&dev->tdev, true);
  	acpi_pm_device_run_wake(&dev->tdev, true);
  }
  
  /* Disable runtime wake capability if it is enabled */
  void zpodd_disable_run_wake(struct ata_device *dev)
  {
  	struct zpodd *zpodd = dev->zpodd;
  
  	if (zpodd->powered_off) {
  		acpi_pm_device_run_wake(&dev->tdev, false);
  		device_set_run_wake(&dev->tdev, false);
  	}
  }
  
  /*
   * Post power on processing after the ODD has been recovered. If the
   * ODD wasn't powered off during suspend, it doesn't do anything.
   *
   * For drawer type ODD, if it is powered on due to user pressed the
   * eject button, the tray needs to be ejected. This can only be done
   * after the ODD has been recovered, i.e. link is initialized and
   * device is able to process NON_DATA PIO command, as eject needs to
   * send command for the ODD to process.
   *
   * The from_notify flag set in wake notification handler function
   * zpodd_wake_dev represents if power on is due to user's action.
   *
   * For both types of ODD, several fields need to be reset.
   */
  void zpodd_post_poweron(struct ata_device *dev)
  {
  	struct zpodd *zpodd = dev->zpodd;
  
  	if (!zpodd->powered_off)
  		return;
  
  	zpodd->powered_off = false;
  
  	if (zpodd->from_notify) {
  		zpodd->from_notify = false;
  		if (zpodd->mech_type == ODD_MECH_TYPE_DRAWER)
  			eject_tray(dev);
  	}
  
  	zpodd->zp_sampled = false;
  	zpodd->zp_ready = false;
  
  	sdev_enable_disk_events(dev->sdev);
  }
  
  static void zpodd_wake_dev(acpi_handle handle, u32 event, void *context)
  {
  	struct ata_device *ata_dev = context;
  	struct zpodd *zpodd = ata_dev->zpodd;
  	struct device *dev = &ata_dev->sdev->sdev_gendev;
  
  	if (event == ACPI_NOTIFY_DEVICE_WAKE && pm_runtime_suspended(dev)) {
  		zpodd->from_notify = true;
  		pm_runtime_resume(dev);
  	}
  }
  
  static void ata_acpi_add_pm_notifier(struct ata_device *dev)
  {
  	acpi_handle handle = ata_dev_acpi_handle(dev);
  	acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
  				    zpodd_wake_dev, dev);
  }
  
  static void ata_acpi_remove_pm_notifier(struct ata_device *dev)
  {
  	acpi_handle handle = ata_dev_acpi_handle(dev);
  	acpi_remove_notify_handler(handle, ACPI_SYSTEM_NOTIFY, zpodd_wake_dev);
  }
  
  void zpodd_init(struct ata_device *dev)
  {
  	struct acpi_device *adev = ACPI_COMPANION(&dev->tdev);
  	enum odd_mech_type mech_type;
  	struct zpodd *zpodd;
  
  	if (dev->zpodd || !adev || !acpi_device_can_poweroff(adev))
  		return;
  
  	mech_type = zpodd_get_mech_type(dev);
  	if (mech_type == ODD_MECH_TYPE_UNSUPPORTED)
  		return;
  
  	zpodd = kzalloc(sizeof(struct zpodd), GFP_KERNEL);
  	if (!zpodd)
  		return;
  
  	zpodd->mech_type = mech_type;
  
  	ata_acpi_add_pm_notifier(dev);
  	zpodd->dev = dev;
  	dev->zpodd = zpodd;
  	dev_pm_qos_expose_flags(&dev->tdev, 0);
  }
  
  void zpodd_exit(struct ata_device *dev)
  {
  	ata_acpi_remove_pm_notifier(dev);
  	kfree(dev->zpodd);
  	dev->zpodd = NULL;
  }