Commit 5ac24697 authored Oct 03, 2006 by Alan Cox Committed by Linus Torvalds Oct 03, 2006

[PATCH] ide: backport piix fixes from libata into the legacy driver



There are three flags being set by default by the PIIX driver for speeds >
PIO 1, and one not being cleared properly on fallback to PIO0.  The most
important one is the prefetch/post write control which only works for ATA
and can do bad things with ATAPI.

The patch does its best to set the flags correctly for drivers/ide.  Its
not 100% perfect but its closer than the original.  100% perfect requires
proper IORDY handling but this isn't critical (and its not right in libata
either ..  yet)

Sergei Shtylyov <sshtylyov@ru.mvista.com> said:

> +					{ 0, 0 },
> +					{ 0, 0 },
> +					{ 1, 0 },
> +					{ 2, 1 },
> +					{ 2, 3 }, };
>
>  	pio = ide_get_best_pio_mode(drive, pio, 5, NULL);

    BTW, there's quite obvious error here which leads to access outside of
timings[] if somebody passes PIO mode 5 (or autotuning code finds out that
drive supports PIO mode 5). Could have been fixed while at it... Those drives
should be rare, though...

> +		}
>  		master_data = master_data | (timings[pio][0] << 12) | (timings[pio][1] << 8);
>  	}
>  	pci_write_config_word(dev, master_port, master_data);

    Actually, there's one more serious issue with piix_tune_drive() -- it
doesn't actually set the drive's own transfer mode.

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent 14e0a193

drivers/ide/pci/piix.c

+22 −9

Original line number	Diff line number	Diff line
		@@ -222,9 +222,11 @@ static void piix_tune_drive (ide_drive_t *drive, u8 pio)
		u16 master_data;
		u8 slave_data;
		static DEFINE_SPINLOCK(tune_lock);
		int control = 0;

		/* ISP RTC */
		u8 timings[][2] = { { 0, 0 },
		static const u8 timings[][2]= {
		{ 0, 0 },
		{ 0, 0 },
		{ 1, 0 },
		{ 2, 1 },
		@@ -239,19 +241,30 @@ static void piix_tune_drive (ide_drive_t *drive, u8 pio)
		*/
		spin_lock_irqsave(&tune_lock, flags);
		pci_read_config_word(dev, master_port, &master_data);

		if (pio >= 2)
		control \|= 1; /* Programmable timing on */
		if (drive->media == ide_disk)
		control \|= 4; /* Prefetch, post write */
		if (pio >= 3)
		control \|= 2; /* IORDY */
		if (is_slave) {
		master_data = master_data \| 0x4000;
		if (pio > 1)
		if (pio > 1) {
		/* enable PPE, IE and TIME */
		master_data = master_data \| 0x0070;
		master_data = master_data \| (control << 4);
		} else {
		master_data &= ~0x0070;
		}
		pci_read_config_byte(dev, slave_port, &slave_data);
		slave_data = slave_data & (hwif->channel ? 0x0f : 0xf0);
		slave_data = slave_data \| (((timings[pio][0] << 2) \| timings[pio][1]) << (hwif->channel ? 4 : 0));
		} else {
		master_data = master_data & 0xccf8;
		if (pio > 1)
		if (pio > 1) {
		/* enable PPE, IE and TIME */
		master_data = master_data \| 0x0007;
		master_data = master_data \| control;
		}
		master_data = master_data \| (timings[pio][0] << 12) \| (timings[pio][1] << 8);
		}
		pci_write_config_word(dev, master_port, master_data);