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/ide-disk.c b/drivers/ide/ide-disk.c
index d8caa65..4b32c4e 100644
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -99,11 +99,6 @@
 	memset(&cmd, 0, sizeof(cmd));
 	cmd.tf_flags = IDE_TFLAG_TF | IDE_TFLAG_DEVICE;
 
-	if (dma == 0) {
-		ide_init_sg_cmd(&cmd, nsectors);
-		ide_map_sg(drive, rq);
-	}
-
 	if (drive->dev_flags & IDE_DFLAG_LBA) {
 		if (lba48) {
 			pr_debug("%s: LBA=0x%012llx\n", drive->name,
@@ -156,6 +151,11 @@
 	ide_tf_set_cmd(drive, &cmd, dma);
 	cmd.rq = rq;
 
+	if (dma == 0) {
+		ide_init_sg_cmd(&cmd, nsectors);
+		ide_map_sg(drive, &cmd);
+	}
+
 	rc = do_rw_taskfile(drive, &cmd);
 
 	if (rc == ide_stopped && dma) {