cmd64x: fix PIO mode setup (take 3)

The driver's tuneproc() method fails to set the drive's own speed -- fix this
by renaming the function to cmd64x_tune_pio(), making it return the mode set,
and "wrapping" the new tuneproc() method around it; while at it, also get rid
of the non-working prefetch control code (filtering out related argument values
in the "wrapper"), remove redundant PIO5 mode limitation, make cmdprintk() give
more sensible mode info, and remove mention about the obsolete /proc/ interface.
Get rid of the broken config_chipset_for_pio() which always tried to set PIO4,
switch to always auto-tuning PIO instead.
Oh, and add the missing PIO5 support to the speedproc() method while at it. :-)

Warning: compile tested only -- getting to the real hardware isn't that easy...

On Tuesday 06 February 2007 22:11, Mikael Pettersson <mikpe@it.uu.se> wrote:
> 
> Worked fine on my SPARC Ultra5 with a CMD646 IDE controller.
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/pci/cmd64x.c

 /* $Id: cmd64x.c,v 1.21 2000/01/30 23:23:16
  *
- * linux/drivers/ide/pci/cmd64x.c		Version 1.30	Sept 10, 2002
+ * linux/drivers/ide/pci/cmd64x.c		Version 1.41	Feb 3, 2007
  *
  * cmd64x.c: Enable interrupts at initialization time on Ultra/PCI machines.
  *           Note, this driver is not used at all on other systems because
@@ -12,6 +12,7 @@
  * Copyright (C) 1998		David S. Miller (davem@redhat.com)
  *
  * Copyright (C) 1999-2002	Andre Hedrick <andre@linux-ide.org>
+ * Copyright (C) 2007		MontaVista Software, Inc. <source@mvista.com>
  */
 
 #include <linux/module.h>
@@ -262,43 +263,25 @@ static void program_drive_counts (ide_drive_t *drive, int setup_count, int activ
 }
 
 /*
- * Attempts to set the interface PIO mode.
- * The preferred method of selecting PIO modes (e.g. mode 4) is 
- * "echo 'piomode:4' > /proc/ide/hdx/settings".  Special cases are
- * 8: prefetch off, 9: prefetch on, 255: auto-select best mode.
- * Called with 255 at boot time.
+ * This routine selects drive's best PIO mode, calculates setup/active/recovery
+ * counts, and then writes them into the chipset registers.
  */
-
-static void cmd64x_tuneproc (ide_drive_t *drive, u8 mode_wanted)
+static u8 cmd64x_tune_pio (ide_drive_t *drive, u8 mode_wanted)
 {
 	int setup_time, active_time, recovery_time;
 	int clock_time, pio_mode, cycle_time;
 	u8 recovery_count2, cycle_count;
 	int setup_count, active_count, recovery_count;
 	int bus_speed = system_bus_clock();
-	/*byte b;*/
 	ide_pio_data_t  d;
 
-	switch (mode_wanted) {
-		case 8: /* set prefetch off */
-		case 9: /* set prefetch on */
-			mode_wanted &= 1;
-			/*set_prefetch_mode(index, mode_wanted);*/
-			cmdprintk("%s: %sabled cmd640 prefetch\n",
-				drive->name, mode_wanted ? "en" : "dis");
-			return;
-	}
-
-	mode_wanted = ide_get_best_pio_mode (drive, mode_wanted, 5, &d);
-	pio_mode = d.pio_mode;
+	pio_mode = ide_get_best_pio_mode(drive, mode_wanted, 5, &d);
 	cycle_time = d.cycle_time;
 
 	/*
 	 * I copied all this complicated stuff from cmd640.c and made a few
 	 * minor changes.  For now I am just going to pray that it is correct.
 	 */
-	if (pio_mode > 5)
-		pio_mode = 5;
 	setup_time  = ide_pio_timings[pio_mode].setup_time;
 	active_time = ide_pio_timings[pio_mode].active_time;
 	recovery_time = cycle_time - (setup_time + active_time);
@@ -320,22 +303,33 @@ static void cmd64x_tuneproc (ide_drive_t *drive, u8 mode_wanted)
 	if (active_count > 16)
 		active_count = 16; /* maximum allowed by cmd646 */
 
-	/*
-	 * In a perfect world, we might set the drive pio mode here
-	 * (using WIN_SETFEATURE) before continuing.
-	 *
-	 * But we do not, because:
-	 *	1) this is the wrong place to do it
-	 *		(proper is do_special() in ide.c)
-	 * 	2) in practice this is rarely, if ever, necessary
-	 */
 	program_drive_counts (drive, setup_count, active_count, recovery_count);
 
-	cmdprintk("%s: selected cmd646 PIO mode%d : %d (%dns)%s, "
+	cmdprintk("%s: PIO mode wanted %d, selected %d (%dns)%s, "
 		"clocks=%d/%d/%d\n",
-		drive->name, pio_mode, mode_wanted, cycle_time,
+		drive->name, mode_wanted, pio_mode, cycle_time,
 		d.overridden ? " (overriding vendor mode)" : "",
 		setup_count, active_count, recovery_count);
+
+	return pio_mode;
+}
+
+/*
+ * Attempts to set drive's PIO mode.
+ * Special cases are 8: prefetch off, 9: prefetch on (both never worked),
+ * and 255: auto-select best mode (used at boot time).
+ */
+static void cmd64x_tune_drive (ide_drive_t *drive, u8 pio)
+{
+	/*
+	 * Filter out the prefetch control values
+	 * to prevent PIO5 from being programmed
+	 */
+	if (pio == 8 || pio == 9)
+		return;
+
+	pio = cmd64x_tune_pio(drive, pio);
+	(void) ide_config_drive_speed(drive, XFER_PIO_0 + pio);
 }
 
 static u8 cmd64x_ratemask (ide_drive_t *drive)
@@ -387,22 +381,6 @@ static u8 cmd64x_ratemask (ide_drive_t *drive)
 	return mode;
 }
 
-static void config_cmd64x_chipset_for_pio (ide_drive_t *drive, u8 set_speed)
-{
-	u8 speed	= 0x00;
-	u8 set_pio	= ide_get_best_pio_mode(drive, 4, 5, NULL);
-
-	cmd64x_tuneproc(drive, set_pio);
-	speed = XFER_PIO_0 + set_pio;
-	if (set_speed)
-		(void) ide_config_drive_speed(drive, speed);
-}
-
-static void config_chipset_for_pio (ide_drive_t *drive, u8 set_speed)
-{
-	config_cmd64x_chipset_for_pio(drive, set_speed);
-}
-
 static int cmd64x_tune_chipset (ide_drive_t *drive, u8 xferspeed)
 {
 	ide_hwif_t *hwif	= HWIF(drive);
@@ -414,7 +392,7 @@ static int cmd64x_tune_chipset (ide_drive_t *drive, u8 xferspeed)
 
 	u8 speed	= ide_rate_filter(cmd64x_ratemask(drive), xferspeed);
 
-	if (speed > XFER_PIO_4) {
+	if (speed >= XFER_SW_DMA_0) {
 		(void) pci_read_config_byte(dev, pciD, &regD);
 		(void) pci_read_config_byte(dev, pciU, &regU);
 		regD &= ~(unit ? 0x40 : 0x20);
@@ -438,17 +416,20 @@ static int cmd64x_tune_chipset (ide_drive_t *drive, u8 xferspeed)
 		case XFER_SW_DMA_2:	regD |= (unit ? 0x40 : 0x10); break;
 		case XFER_SW_DMA_1:	regD |= (unit ? 0x80 : 0x20); break;
 		case XFER_SW_DMA_0:	regD |= (unit ? 0xC0 : 0x30); break;
-		case XFER_PIO_4:	cmd64x_tuneproc(drive, 4); break;
-		case XFER_PIO_3:	cmd64x_tuneproc(drive, 3); break;
-		case XFER_PIO_2:	cmd64x_tuneproc(drive, 2); break;
-		case XFER_PIO_1:	cmd64x_tuneproc(drive, 1); break;
-		case XFER_PIO_0:	cmd64x_tuneproc(drive, 0); break;
+		case XFER_PIO_5:
+		case XFER_PIO_4:
+		case XFER_PIO_3:
+		case XFER_PIO_2:
+		case XFER_PIO_1:
+		case XFER_PIO_0:
+			(void) cmd64x_tune_pio(drive, speed - XFER_PIO_0);
+			break;
 
 		default:
 			return 1;
 	}
 
-	if (speed > XFER_PIO_4) {
+	if (speed >= XFER_SW_DMA_0) {
 		(void) pci_write_config_byte(dev, pciU, regU);
 		regD |= (unit ? 0x40 : 0x20);
 		(void) pci_write_config_byte(dev, pciD, regD);
@@ -461,8 +442,6 @@ static int config_chipset_for_dma (ide_drive_t *drive)
 {
 	u8 speed	= ide_dma_speed(drive, cmd64x_ratemask(drive));
 
-	config_chipset_for_pio(drive, !speed);
-
 	if (!speed)
 		return 0;
 
@@ -478,7 +457,7 @@ static int cmd64x_config_drive_for_dma (ide_drive_t *drive)
 		return 0;
 
 	if (ide_use_fast_pio(drive))
-		config_chipset_for_pio(drive, 1);
+		cmd64x_tune_drive(drive, 255);
 
 	return -1;
 }
@@ -679,14 +658,13 @@ static void __devinit init_hwif_cmd64x(ide_hwif_t *hwif)
 	pci_read_config_dword(dev, PCI_CLASS_REVISION, &class_rev);
 	class_rev &= 0xff;
 
-	hwif->tuneproc  = &cmd64x_tuneproc;
+	hwif->tuneproc  = &cmd64x_tune_drive;
 	hwif->speedproc = &cmd64x_tune_chipset;
 
-	if (!hwif->dma_base) {
-		hwif->drives[0].autotune = 1;
-		hwif->drives[1].autotune = 1;
+	hwif->drives[0].autotune = hwif->drives[1].autotune = 1;
+
+	if (!hwif->dma_base)
 		return;
-	}
 
 	hwif->atapi_dma = 1;