libata: implement spurious irq handling for SFF and apply it to piix

[safe/jmp/linux-2.6] / drivers / ata / libata-sff.c

diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index 730ef3c..c2661ea 100644 (file)
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -1763,24 +1763,50 @@ irqreturn_t ata_sff_interrupt(int irq, void *dev_instance)
 {
        struct ata_host *host = dev_instance;
        unsigned int i;
-       unsigned int handled = 0;
+       unsigned int handled = 0, polling = 0;
        unsigned long flags;
 
        /* TODO: make _irqsave conditional on x86 PCI IDE legacy mode */
        spin_lock_irqsave(&host->lock, flags);
 
        for (i = 0; i < host->n_ports; i++) {
-               struct ata_port *ap;
+               struct ata_port *ap = host->ports[i];
+               struct ata_queued_cmd *qc;
 
-               ap = host->ports[i];
-               if (ap &&
-                   !(ap->flags & ATA_FLAG_DISABLED)) {
-                       struct ata_queued_cmd *qc;
+               if (unlikely(ap->flags & ATA_FLAG_DISABLED))
+                       continue;
 
-                       qc = ata_qc_from_tag(ap, ap->link.active_tag);
-                       if (qc && (!(qc->tf.flags & ATA_TFLAG_POLLING)) &&
-                           (qc->flags & ATA_QCFLAG_ACTIVE))
+               qc = ata_qc_from_tag(ap, ap->link.active_tag);
+               if (qc) {
+                       if (!(qc->tf.flags & ATA_TFLAG_POLLING))
                                handled |= ata_sff_host_intr(ap, qc);
+                       else
+                               polling |= 1 << i;
+               }
+       }
+
+       /*
+        * If no port was expecting IRQ but the controller is actually
+        * asserting IRQ line, nobody cared will ensue.  Check IRQ
+        * pending status if available and clear spurious IRQ.
+        */
+       if (!handled) {
+               for (i = 0; i < host->n_ports; i++) {
+                       struct ata_port *ap = host->ports[i];
+
+                       if (polling & (1 << i))
+                               continue;
+
+                       if (!ap->ops->sff_irq_check ||
+                           !ap->ops->sff_irq_check(ap))
+                               continue;
+
+                       if (printk_ratelimit())
+                               ata_port_printk(ap, KERN_INFO,
+                                               "clearing spurious IRQ\n");
+
+                       ap->ops->sff_check_status(ap);
+                       ap->ops->sff_irq_clear(ap);
                }
        }