[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 0b5d3a5b7eda..8b5a3f00083d 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 f178894edd04..ca5fcadf9981 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 505160ab472b..d33e70361a7d 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);