ide: remove unnecessary writes to HOB taskfile registers

* Set taskfile flags for REQ_TYPE_ATA_TASKFILE requests before
  adding the request to the queue.

* Cleanup execute_drive_cmd().

* Remove unnecessary writes to HOB taskfile registers when using
  LBA48 disk for the following cases:

  - Power Management requests
    (WIN_FLUSH_CACHE[_EXT], WIN_STANDBYNOW1, WIN_IDLEIMMEDIATE commands)

  - special commands (WIN_SPECIFY, WIN_RESTORE, WIN_SETMULT)

  - Host Protected Area support (WIN_READ_NATIVE_MAX, WIN_SET_MAX)

  - /proc/ide/ SMART support (WIN_SMART with SMART_ENABLE,
    SMART_READ_VALUES and SMART_READ_THRESHOLDS subcommands)

  - write cache enabling/disabling in ide-disk
    (WIN_SETFEATURES with SETFEATURES_{EN,DIS}_WCACHE)

  - write cache flushing in ide-disk (WIN_FLUSH_CACHE[_EXT])

  - acoustic management in ide-disk
    (WIN_SETFEATURES with SETFEATURES_{EN,DIS}_AAM)

  - door (un)locking in ide-disk (WIN_DOORLOCK, WIN_DOORUNLOCK)

  - /proc/ide/hd?/identify support (WIN_IDENTIFY)

  - ACPI _GTF taskfiles

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide-taskfile.c

@@ -126,6 +126,7 @@ int taskfile_lib_get_identify (ide_drive_t *drive, u8 *buf)
 		args.tf.command = WIN_IDENTIFY;
 	else
 		args.tf.command = WIN_PIDENTIFY;
+	args.tf_flags = IDE_TFLAG_OUT_TF | IDE_TFLAG_OUT_DEVICE;
 	args.command_type = IDE_DRIVE_TASK_IN;
 	args.data_phase   = TASKFILE_IN;
 	args.handler	  = &task_in_intr;
@@ -619,6 +620,10 @@ int ide_taskfile_ioctl (ide_drive_t *drive, unsigned int cmd, unsigned long arg)
 	args.data_phase   = req_task->data_phase;
 	args.command_type = req_task->req_cmd;
 
+	args.tf_flags = IDE_TFLAG_OUT_DEVICE;
+	if (drive->addressing == 1)
+		args.tf_flags |= IDE_TFLAG_LBA48;
+
 	if (req_task->out_flags.all) {
 		args.tf_flags |= IDE_TFLAG_FLAGGED;
 
@@ -644,6 +649,10 @@ int ide_taskfile_ioctl (ide_drive_t *drive, unsigned int cmd, unsigned long arg)
 			args.tf_flags |= IDE_TFLAG_OUT_LBAM;
 		if (req_task->out_flags.b.hcyl)
 			args.tf_flags |= IDE_TFLAG_OUT_LBAH;
+	} else {
+		args.tf_flags |= IDE_TFLAG_OUT_TF;
+		if (args.tf_flags & IDE_TFLAG_LBA48)
+			args.tf_flags |= IDE_TFLAG_OUT_HOB;
 	}
 
 	drive->io_32bit = 0;