libata/pata_it821x: Improve handling of poorly compatible emulations

Some it821x RAID firmwares return 0 for the err return off both devices.
A similar issue occurs with the slave returning 0 not 1 if you plug a
gigabyte sata ramdisk into a controller that fakes two SATA ports as
master/slave on an SFF channel.

The patch does the following

- Allow the 'failed diagnostics' case on both master and slave
- Move the HORKAGE_DIAGNOSTIC check after ->dev_config

This second change also allows IT821x to fix up a problem where we report
drive diagnostic failures when in fact the drive is fine but the
microcontroller firmware doesn't appear to get it right. IT821x clears
the flag again to avoid giving the user bogus warnings about their disk.

The other IT821x change is a bit ugly, we slightly abuse the cable type
hook to fiddle with the identify data for the devices. We could add a new
hook for this but as we have only one offender and no more seeming likely
it seems better to keep libata-core clean.

Please let this sit in -mm briefly, just in case the relaxed checking
breaks some other emulated interface.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 33 insertions, 2 deletions

diff --git a/drivers/ata/pata_it821x.c b/drivers/ata/pata_it821x.c
index ca9aae09daed..109ddd42c266 100644
--- a/drivers/ata/pata_it821x.c
+++ b/drivers/ata/pata_it821x.c
@@ -430,7 +430,7 @@ static unsigned int it821x_smart_qc_issue_prot(struct ata_queued_cmd *qc)
 			return ata_qc_issue_prot(qc);
 	}
 	printk(KERN_DEBUG "it821x: can't process command 0x%02X\n", qc->tf.command);
-	return AC_ERR_INVALID;
+	return AC_ERR_DEV;
 }
 
 /**
@@ -516,6 +516,37 @@ static void it821x_dev_config(struct ata_device *adev)
 			printk("(%dK stripe)", adev->id[146]);
 		printk(".\n");
 	}
+	/* This is a controller firmware triggered funny, don't
+	   report the drive faulty! */
+	adev->horkage &= ~ATA_HORKAGE_DIAGNOSTIC;
+}
+
+/**
+ *	it821x_ident_hack	-	Hack identify data up
+ *	@ap: Port
+ *
+ *	Walk the devices on this firmware driven port and slightly
+ *	mash the identify data to stop us and common tools trying to
+ *	use features not firmware supported. The firmware itself does
+ *	some masking (eg SMART) but not enough.
+ *
+ *	This is a bit of an abuse of the cable method, but it is the
+ *	only method called at the right time. We could modify the libata
+ *	core specifically for ident hacking but while we have one offender
+ *	it seems better to keep the fallout localised.
+ */
+
+static int it821x_ident_hack(struct ata_port *ap)
+{
+	struct ata_device *adev;
+	ata_link_for_each_dev(adev, &ap->link) {
+		if (ata_dev_enabled(adev)) {
+			adev->id[84] &= ~(1 << 6);	/* No FUA */
+			adev->id[85] &= ~(1 << 10);	/* No HPA */
+			adev->id[76] = 0;		/* No NCQ/AN etc */
+		}
+	}
+	return ata_cable_unknown(ap);
 }
 
 
@@ -634,7 +665,7 @@ static struct ata_port_operations it821x_smart_port_ops = {
 	.thaw		= ata_bmdma_thaw,
 	.error_handler	= ata_bmdma_error_handler,
 	.post_internal_cmd = ata_bmdma_post_internal_cmd,
-	.cable_detect	= ata_cable_unknown,
+	.cable_detect	= it821x_ident_hack,
 
 	.bmdma_setup 	= ata_bmdma_setup,
 	.bmdma_start 	= ata_bmdma_start,