ide: pass command to ide_map_sg()

* Set IDE_TFLAG_WRITE flag and ->rq also for ATA_CMD_PACKET
  commands.

* Pass command to ->dma_setup method and update all its
  implementations accordingly.

* Pass command instead of request to ide_build_sglist(),
  *_build_dmatable() and ide_map_sg().

While at it:

* Fix scc_dma_setup() documentation + use ATA_DMA_WR define.

* Rename sgiioc4_build_dma_table() to sgiioc4_build_dmatable(),
  change return value type to 'int' and drop unused 'ddir'
  argument.

* Do some minor cleanups in [tx4939]ide_dma_setup().

There should be no functional changes caused by this patch.

Acked-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/au1xxx-ide.c b/drivers/ide/au1xxx-ide.c
index 3ace0cd..58485d6 100644
--- a/drivers/ide/au1xxx-ide.c
+++ b/drivers/ide/au1xxx-ide.c
@@ -209,15 +209,14 @@
  */
 
 #ifdef CONFIG_BLK_DEV_IDE_AU1XXX_MDMA2_DBDMA
-static int auide_build_dmatable(ide_drive_t *drive)
+static int auide_build_dmatable(ide_drive_t *drive, struct ide_cmd *cmd)
 {
 	ide_hwif_t *hwif = drive->hwif;
-	struct request *rq = hwif->rq;
 	_auide_hwif *ahwif = &auide_hwif;
 	struct scatterlist *sg;
-	int i = hwif->cmd.sg_nents, iswrite, count = 0;
+	int i = cmd->sg_nents, count = 0;
+	int iswrite = !!(cmd->tf_flags & IDE_TFLAG_WRITE);
 
-	iswrite = (rq_data_dir(rq) == WRITE);
 	/* Save for interrupt context */
 	ahwif->drive = drive;
 
@@ -298,12 +297,10 @@
 			    (2*WAIT_CMD), NULL);
 }
 
-static int auide_dma_setup(ide_drive_t *drive)
+static int auide_dma_setup(ide_drive_t *drive, struct ide_cmd *cmd)
 {
-	struct request *rq = drive->hwif->rq;
-
-	if (!auide_build_dmatable(drive)) {
-		ide_map_sg(drive, rq);
+	if (auide_build_dmatable(drive, cmd) == 0) {
+		ide_map_sg(drive, cmd);
 		return 1;
 	}