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/sgiioc4.c b/drivers/ide/sgiioc4.c
index b0769e9..b12de83 100644
--- a/drivers/ide/sgiioc4.c
+++ b/drivers/ide/sgiioc4.c
@@ -424,12 +424,11 @@
 /* | Upper 32 bits - Zero	    |EOL| 15 unused     | 16 Bit Length| */
 /* --------------------------------------------------------------------- */
 /* Creates the scatter gather list, DMA Table */
-static unsigned int
-sgiioc4_build_dma_table(ide_drive_t * drive, struct request *rq, int ddir)
+static int sgiioc4_build_dmatable(ide_drive_t *drive, struct ide_cmd *cmd)
 {
 	ide_hwif_t *hwif = drive->hwif;
 	unsigned int *table = hwif->dmatable_cpu;
-	unsigned int count = 0, i = hwif->cmd.sg_nents;
+	unsigned int count = 0, i = cmd->sg_nents;
 	struct scatterlist *sg = hwif->sg_table;
 
 	while (i && sg_dma_len(sg)) {
@@ -484,24 +483,18 @@
 	return 0;		/* revert to PIO for this request */
 }
 
-static int sgiioc4_dma_setup(ide_drive_t *drive)
+static int sgiioc4_dma_setup(ide_drive_t *drive, struct ide_cmd *cmd)
 {
-	struct request *rq = drive->hwif->rq;
-	unsigned int count = 0;
 	int ddir;
+	u8 write = !!(cmd->tf_flags & IDE_TFLAG_WRITE);
 
-	if (rq_data_dir(rq))
-		ddir = PCI_DMA_TODEVICE;
-	else
-		ddir = PCI_DMA_FROMDEVICE;
-
-	if (!(count = sgiioc4_build_dma_table(drive, rq, ddir))) {
+	if (sgiioc4_build_dmatable(drive, cmd) == 0) {
 		/* try PIO instead of DMA */
-		ide_map_sg(drive, rq);
+		ide_map_sg(drive, cmd);
 		return 1;
 	}
 
-	if (rq_data_dir(rq))
+	if (write)
 		/* Writes TO the IOC4 FROM Main Memory */
 		ddir = IOC4_DMA_READ;
 	else