3 files changed, 76 insertions, 6 deletions

diff --git a/Documentation/DocBook/libata.tmpl b/Documentation/DocBook/libata.tmpl
index d260d92089ad..5bcbb6ee3bc0 100644
--- a/Documentation/DocBook/libata.tmpl
+++ b/Documentation/DocBook/libata.tmpl
@@ -120,14 +120,27 @@ void (*dev_config) (struct ata_port *, struct ata_device *);
         <programlisting>
 void (*set_piomode) (struct ata_port *, struct ata_device *);
 void (*set_dmamode) (struct ata_port *, struct ata_device *);
-void (*post_set_mode) (struct ata_port *ap);
+void (*post_set_mode) (struct ata_port *);
+unsigned int (*mode_filter) (struct ata_port *, struct ata_device *, unsigned int);
         </programlisting>
 
         <para>
         Hooks called prior to the issue of SET FEATURES - XFER MODE
-        command.  dev->pio_mode is guaranteed to be valid when
-        ->set_piomode() is called, and dev->dma_mode is guaranteed to be
-        valid when ->set_dmamode() is called.  ->post_set_mode() is
+        command.  The optional ->mode_filter() hook is called when libata
+        has built a mask of the possible modes. This is passed to the 
+        ->mode_filter() function which should return a mask of valid modes
+        after filtering those unsuitable due to hardware limits. It is not
+        valid to use this interface to add modes.
+        </para>
+        <para>
+        dev->pio_mode and dev->dma_mode are guaranteed to be valid when
+        ->set_piomode() and when ->set_dmamode() is called. The timings for
+        any other drive sharing the cable will also be valid at this point.
+        That is the library records the decisions for the modes of each
+        drive on a channel before it attempts to set any of them.
+        </para>
+        <para>
+        ->post_set_mode() is
         called unconditionally, after the SET FEATURES - XFER MODE
         command completes successfully.
         </para>
@@ -230,6 +243,32 @@ void (*dev_select)(struct ata_port *ap, unsigned int device);
 
         </sect2>
 
+        <sect2><title>Private tuning method</title>
+        <programlisting>
+void (*set_mode) (struct ata_port *ap);
+        </programlisting>
+
+        <para>
+        By default libata performs drive and controller tuning in
+        accordance with the ATA timing rules and also applies blacklists
+        and cable limits. Some controllers need special handling and have
+        custom tuning rules, typically raid controllers that use ATA
+        commands but do not actually do drive timing.
+        </para>
+
+        <warning>
+        <para>
+        This hook should not be used to replace the standard controller
+        tuning logic when a controller has quirks. Replacing the default
+        tuning logic in that case would bypass handling for drive and
+        bridge quirks that may be important to data reliability. If a
+        controller needs to filter the mode selection it should use the
+        mode_filter hook instead.
+        </para>
+        </warning>
+
+        </sect2>
+
         <sect2><title>Reset ATA bus</title>
         <programlisting>
 void (*phy_reset) (struct ata_port *ap);
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 41659448a204..b1ddf40533b5 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1818,7 +1818,7 @@ static void ata_host_set_dma(struct ata_port *ap)
  */
 static void ata_set_mode(struct ata_port *ap)
 {
-        int i, rc;
+        int i, rc, used_dma = 0;
 
         /* step 1: calculate xfer_mask */
         for (i = 0; i < ATA_MAX_DEVICES; i++) {
@@ -1836,6 +1836,9 @@ static void ata_set_mode(struct ata_port *ap)
                 dma_mask = ata_pack_xfermask(0, dev->mwdma_mask, dev->udma_mask);
                 dev->pio_mode = ata_xfer_mask2mode(pio_mask);
                 dev->dma_mode = ata_xfer_mask2mode(dma_mask);
+
+                if (dev->dma_mode)
+                        used_dma = 1;
         }
 
         /* step 2: always set host PIO timings */
@@ -1857,6 +1860,17 @@ static void ata_set_mode(struct ata_port *ap)
                         goto err_out;
         }
 
+        /*
+         *      Record simplex status. If we selected DMA then the other
+         *      host channels are not permitted to do so.
+         */
+
+        if (used_dma && (ap->host_set->flags & ATA_HOST_SIMPLEX))
+                ap->host_set->simplex_claimed = 1;
+
+        /*
+         *      Chip specific finalisation
+         */
         if (ap->ops->post_set_mode)
                 ap->ops->post_set_mode(ap);
 
@@ -2646,13 +2660,14 @@ static int ata_dma_blacklisted(const struct ata_device *dev)
  */
 static void ata_dev_xfermask(struct ata_port *ap, struct ata_device *dev)
 {
+        struct ata_host_set *hs = ap->host_set;
         unsigned long xfer_mask;
         int i;
 
         xfer_mask = ata_pack_xfermask(ap->pio_mask, ap->mwdma_mask,
                                       ap->udma_mask);
 
-        /* use port-wide xfermask for now */
+        /* FIXME: Use port-wide xfermask for now */
         for (i = 0; i < ATA_MAX_DEVICES; i++) {
                 struct ata_device *d = &ap->device[i];
                 if (!ata_dev_present(d))
@@ -2662,12 +2677,23 @@ static void ata_dev_xfermask(struct ata_port *ap, struct ata_device *dev)
                 xfer_mask &= ata_id_xfermask(d->id);
                 if (ata_dma_blacklisted(d))
                         xfer_mask &= ~(ATA_MASK_MWDMA | ATA_MASK_UDMA);
+                /* Apply cable rule here. Don't apply it early because when
+                   we handle hot plug the cable type can itself change */
+                if (ap->cbl == ATA_CBL_PATA40)
+                        xfer_mask &= ~(0xF8 << ATA_SHIFT_UDMA);
         }
 
         if (ata_dma_blacklisted(dev))
                 printk(KERN_WARNING "ata%u: dev %u is on DMA blacklist, "
                        "disabling DMA\n", ap->id, dev->devno);
 
+        if (hs->flags & ATA_HOST_SIMPLEX) {
+                if (hs->simplex_claimed)
+                        xfer_mask &= ~(ATA_MASK_MWDMA | ATA_MASK_UDMA);
+        }
+        if (ap->ops->mode_filter)
+                xfer_mask = ap->ops->mode_filter(ap, dev, xfer_mask);
+
         ata_unpack_xfermask(xfer_mask, &dev->pio_mask, &dev->mwdma_mask,
                             &dev->udma_mask);
 }
@@ -4531,6 +4557,7 @@ int ata_device_add(const struct ata_probe_ent *ent)
         host_set->mmio_base = ent->mmio_base;
         host_set->private_data = ent->private_data;
         host_set->ops = ent->port_ops;
+        host_set->flags = ent->host_set_flags;
 
         /* register each port bound to this device */
         for (i = 0; i < ent->n_ports; i++) {
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 6a9316cbb70b..0d61357604d5 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -294,6 +294,9 @@ struct ata_host_set {
         unsigned int            n_ports;
         void                    *private_data;
         const struct ata_port_operations *ops;
+        unsigned long           flags;
+        int                     simplex_claimed;        /* Keep seperate in case we
+                                                           ever need to do this locked */
         struct ata_port *       ports[0];
 };
 
@@ -423,6 +426,7 @@ struct ata_port_operations {
 
         void (*set_piomode) (struct ata_port *, struct ata_device *);
         void (*set_dmamode) (struct ata_port *, struct ata_device *);
+        unsigned long (*mode_filter) (const struct ata_port *, struct ata_device *, unsigned long);
 
         void (*tf_load) (struct ata_port *ap, const struct ata_taskfile *tf);
         void (*tf_read) (struct ata_port *ap, struct ata_taskfile *tf);