[PATCH] libata basic detection and errata for PATA->SATA bridges

This patch works around an issue with WD drives (and possibly others)
over SiL PATA->SATA Bridges on SATA controllers locking up with
transfers > 200 sectors.

Signed-off-by: Brad Campbell <brad@wasp.net.au>

3 files changed, 35 insertions, 2 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 0b5d3a5b7edab..8b5a3f00083d8 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1186,6 +1186,37 @@ err_out:
 	DPRINTK("EXIT, err\n");
 }
 
+
+static inline u8 ata_dev_knobble(struct ata_port *ap)
+{
+	return ((ap->cbl == ATA_CBL_SATA) && (!ata_id_is_sata(ap->device->id)));
+}
+
+/**
+ * 	ata_dev_config - Run device specific handlers and check for
+ * 			 SATA->PATA bridges
+ * 	@ap: Bus 
+ * 	@i:  Device
+ *
+ * 	LOCKING:
+ */
+ 
+void ata_dev_config(struct ata_port *ap, unsigned int i)
+{
+	/* limit bridge transfers to udma5, 200 sectors */
+	if (ata_dev_knobble(ap)) {
+		printk(KERN_INFO "ata%u(%u): applying bridge limits\n",
+			ap->id, ap->device->devno);
+		ap->udma_mask &= ATA_UDMA5;
+		ap->host->max_sectors = ATA_MAX_SECTORS;
+		ap->host->hostt->max_sectors = ATA_MAX_SECTORS;
+		ap->device->flags |= ATA_DFLAG_LOCK_SECTORS;
+	}
+
+	if (ap->ops->dev_config)
+		ap->ops->dev_config(ap, &ap->device[i]);
+}
+
 /**
  *	ata_bus_probe - Reset and probe ATA bus
  *	@ap: Bus to probe
@@ -1208,8 +1239,7 @@ static int ata_bus_probe(struct ata_port *ap)
 		ata_dev_identify(ap, i);
 		if (ata_dev_present(&ap->device[i])) {
 			found = 1;
-			if (ap->ops->dev_config)
-				ap->ops->dev_config(ap, &ap->device[i]);
+			ata_dev_config(ap,i);
 		}
 	}
 
@@ -4014,6 +4044,7 @@ EXPORT_SYMBOL_GPL(ata_scsi_release);
 EXPORT_SYMBOL_GPL(ata_host_intr);
 EXPORT_SYMBOL_GPL(ata_dev_classify);
 EXPORT_SYMBOL_GPL(ata_dev_id_string);
+EXPORT_SYMBOL_GPL(ata_dev_config);
 EXPORT_SYMBOL_GPL(ata_scsi_simulate);
 
 #ifdef CONFIG_PCI
diff --git a/include/linux/ata.h b/include/linux/ata.h
index f178894edd04f..ca5fcadf99819 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -224,6 +224,7 @@ struct ata_taskfile {
 };
 
 #define ata_id_is_ata(id)	(((id)[0] & (1 << 15)) == 0)
+#define ata_id_is_sata(id)	((id)[93] == 0)
 #define ata_id_rahead_enabled(id) ((id)[85] & (1 << 6))
 #define ata_id_wcache_enabled(id) ((id)[85] & (1 << 5))
 #define ata_id_has_flush(id) ((id)[83] & (1 << 12))
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 505160ab472b0..d33e70361a7d8 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -420,6 +420,7 @@ extern void ata_sg_init(struct ata_queued_cmd *qc, struct scatterlist *sg,
 extern unsigned int ata_dev_classify(struct ata_taskfile *tf);
 extern void ata_dev_id_string(u16 *id, unsigned char *s,
 			      unsigned int ofs, unsigned int len);
+extern void ata_dev_config(struct ata_port *ap, unsigned int i);
 extern void ata_bmdma_setup (struct ata_queued_cmd *qc);
 extern void ata_bmdma_start (struct ata_queued_cmd *qc);
 extern void ata_bmdma_stop(struct ata_port *ap);