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/trm290.c b/drivers/ide/trm290.c
index e8279f3..746858a 100644
--- a/drivers/ide/trm290.c
+++ b/drivers/ide/trm290.c
@@ -181,13 +181,12 @@
 	ide_execute_command(drive, command, &ide_dma_intr, WAIT_CMD, NULL);
 }
 
-static int trm290_dma_setup(ide_drive_t *drive)
+static int trm290_dma_setup(ide_drive_t *drive, struct ide_cmd *cmd)
 {
 	ide_hwif_t *hwif = drive->hwif;
-	struct request *rq = hwif->rq;
 	unsigned int count, rw;
 
-	if (rq_data_dir(rq)) {
+	if (cmd->tf_flags & IDE_TFLAG_WRITE) {
 #ifdef TRM290_NO_DMA_WRITES
 		/* always use PIO for writes */
 		trm290_prepare_drive(drive, 0);	/* select PIO xfer */
@@ -197,8 +196,9 @@
 	} else
 		rw = 2;
 
-	if (!(count = ide_build_dmatable(drive, rq))) {
-		ide_map_sg(drive, rq);
+	count = ide_build_dmatable(drive, cmd);
+	if (count == 0) {
+		ide_map_sg(drive, cmd);
 		/* try PIO instead of DMA */
 		trm290_prepare_drive(drive, 0); /* select PIO xfer */
 		return 1;