+static inline void ata_eh_pull_park_action(struct ata_port *ap)
+{
+ struct ata_link *link;
+ struct ata_device *dev;
+ unsigned long flags;
+
+ /*
+ * This function can be thought of as an extended version of
+ * ata_eh_about_to_do() specially crafted to accommodate the
+ * requirements of ATA_EH_PARK handling. Since the EH thread
+ * does not leave the do {} while () loop in ata_eh_recover as
+ * long as the timeout for a park request to *one* device on
+ * the port has not expired, and since we still want to pick
+ * up park requests to other devices on the same port or
+ * timeout updates for the same device, we have to pull
+ * ATA_EH_PARK actions from eh_info into eh_context.i
+ * ourselves at the beginning of each pass over the loop.
+ *
+ * Additionally, all write accesses to &ap->park_req_pending
+ * through INIT_COMPLETION() (see below) or complete_all()
+ * (see ata_scsi_park_store()) are protected by the host lock.
+ * As a result we have that park_req_pending.done is zero on
+ * exit from this function, i.e. when ATA_EH_PARK actions for
+ * *all* devices on port ap have been pulled into the
+ * respective eh_context structs. If, and only if,
+ * park_req_pending.done is non-zero by the time we reach
+ * wait_for_completion_timeout(), another ATA_EH_PARK action
+ * has been scheduled for at least one of the devices on port
+ * ap and we have to cycle over the do {} while () loop in
+ * ata_eh_recover() again.
+ */
+
+ spin_lock_irqsave(ap->lock, flags);
+ INIT_COMPLETION(ap->park_req_pending);
+ ata_port_for_each_link(link, ap) {
+ ata_link_for_each_dev(dev, link) {
+ struct ata_eh_info *ehi = &link->eh_info;
+
+ link->eh_context.i.dev_action[dev->devno] |=
+ ehi->dev_action[dev->devno] & ATA_EH_PARK;
+ ata_eh_clear_action(link, dev, ehi, ATA_EH_PARK);
+ }
+ }
+ spin_unlock_irqrestore(ap->lock, flags);
+}
+
+static void ata_eh_park_issue_cmd(struct ata_device *dev, int park)
+{
+ struct ata_eh_context *ehc = &dev->link->eh_context;
+ struct ata_taskfile tf;
+ unsigned int err_mask;
+
+ ata_tf_init(dev, &tf);
+ if (park) {
+ ehc->unloaded_mask |= 1 << dev->devno;
+ tf.command = ATA_CMD_IDLEIMMEDIATE;
+ tf.feature = 0x44;
+ tf.lbal = 0x4c;
+ tf.lbam = 0x4e;
+ tf.lbah = 0x55;
+ } else {
+ ehc->unloaded_mask &= ~(1 << dev->devno);
+ tf.command = ATA_CMD_CHK_POWER;
+ }
+
+ tf.flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
+ tf.protocol |= ATA_PROT_NODATA;
+ err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
+ if (park && (err_mask || tf.lbal != 0xc4)) {
+ ata_dev_printk(dev, KERN_ERR, "head unload failed!\n");
+ ehc->unloaded_mask &= ~(1 << dev->devno);
+ }
+}
+