1 files changed, 88 insertions, 3 deletions

diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index f93dc029dfde..8332e97a9de3 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -52,6 +52,7 @@ const struct ata_port_operations ata_sff_port_ops = {
 	.softreset		= ata_sff_softreset,
 	.hardreset		= sata_sff_hardreset,
 	.postreset		= ata_sff_postreset,
+	.drain_fifo		= ata_sff_drain_fifo,
 	.error_handler		= ata_sff_error_handler,
 	.post_internal_cmd	= ata_sff_post_internal_cmd,
 
@@ -64,6 +65,8 @@ const struct ata_port_operations ata_sff_port_ops = {
 	.sff_irq_on		= ata_sff_irq_on,
 	.sff_irq_clear		= ata_sff_irq_clear,
 
+	.lost_interrupt		= ata_sff_lost_interrupt,
+
 	.port_start		= ata_sff_port_start,
 };
 EXPORT_SYMBOL_GPL(ata_sff_port_ops);
@@ -1646,7 +1649,7 @@ EXPORT_SYMBOL_GPL(ata_sff_qc_fill_rtf);
  *	RETURNS:
  *	One if interrupt was handled, zero if not (shared irq).
  */
-inline unsigned int ata_sff_host_intr(struct ata_port *ap,
+unsigned int ata_sff_host_intr(struct ata_port *ap,
 				      struct ata_queued_cmd *qc)
 {
 	struct ata_eh_info *ehi = &ap->link.eh_info;
@@ -1775,6 +1778,48 @@ irqreturn_t ata_sff_interrupt(int irq, void *dev_instance)
 EXPORT_SYMBOL_GPL(ata_sff_interrupt);
 
 /**
+ *	ata_sff_lost_interrupt	-	Check for an apparent lost interrupt
+ *	@ap: port that appears to have timed out
+ *
+ *	Called from the libata error handlers when the core code suspects
+ *	an interrupt has been lost. If it has complete anything we can and
+ *	then return. Interface must support altstatus for this faster
+ *	recovery to occur.
+ *
+ *	Locking:
+ *	Caller holds host lock
+ */
+
+void ata_sff_lost_interrupt(struct ata_port *ap)
+{
+	u8 status;
+	struct ata_queued_cmd *qc;
+
+	/* Only one outstanding command per SFF channel */
+	qc = ata_qc_from_tag(ap, ap->link.active_tag);
+	/* Check we have a live one.. */
+	if (qc == NULL ||  !(qc->flags & ATA_QCFLAG_ACTIVE))
+		return;
+	/* We cannot lose an interrupt on a polled command */
+	if (qc->tf.flags & ATA_TFLAG_POLLING)
+		return;
+	/* See if the controller thinks it is still busy - if so the command
+	   isn't a lost IRQ but is still in progress */
+	status = ata_sff_altstatus(ap);
+	if (status & ATA_BUSY)
+		return;
+
+	/* There was a command running, we are no longer busy and we have
+	   no interrupt. */
+	ata_port_printk(ap, KERN_WARNING, "lost interrupt (Status 0x%x)\n",
+								status);
+	/* Run the host interrupt logic as if the interrupt had not been
+	   lost */
+	ata_sff_host_intr(ap, qc);
+}
+EXPORT_SYMBOL_GPL(ata_sff_lost_interrupt);
+
+/**
  *	ata_sff_freeze - Freeze SFF controller port
  *	@ap: port to freeze
  *
@@ -2199,6 +2244,39 @@ void ata_sff_postreset(struct ata_link *link, unsigned int *classes)
 EXPORT_SYMBOL_GPL(ata_sff_postreset);
 
 /**
+ *	ata_sff_drain_fifo - Stock FIFO drain logic for SFF controllers
+ *	@qc: command
+ *
+ *	Drain the FIFO and device of any stuck data following a command
+ *	failing to complete. In some cases this is neccessary before a
+ *	reset will recover the device.
+ *
+ */
+
+void ata_sff_drain_fifo(struct ata_queued_cmd *qc)
+{
+	int count;
+	struct ata_port *ap;
+
+	/* We only need to flush incoming data when a command was running */
+	if (qc == NULL || qc->dma_dir == DMA_TO_DEVICE)
+		return;
+
+	ap = qc->ap;
+	/* Drain up to 64K of data before we give up this recovery method */
+	for (count = 0; (ap->ops->sff_check_status(ap) & ATA_DRQ)
+						&& count < 32768; count++)
+		ioread16(ap->ioaddr.data_addr);
+
+	/* Can become DEBUG later */
+	if (count)
+		ata_port_printk(ap, KERN_DEBUG,
+			"drained %d bytes to clear DRQ.\n", count);
+
+}
+EXPORT_SYMBOL_GPL(ata_sff_drain_fifo);
+
+/**
  *	ata_sff_error_handler - Stock error handler for BMDMA controller
  *	@ap: port to handle error for
  *
@@ -2239,7 +2317,8 @@ void ata_sff_error_handler(struct ata_port *ap)
 		 * really a timeout event, adjust error mask and
 		 * cancel frozen state.
 		 */
-		if (qc->err_mask == AC_ERR_TIMEOUT && (host_stat & ATA_DMA_ERR)) {
+		if (qc->err_mask == AC_ERR_TIMEOUT
+						&& (host_stat & ATA_DMA_ERR)) {
 			qc->err_mask = AC_ERR_HOST_BUS;
 			thaw = 1;
 		}
@@ -2250,6 +2329,13 @@ void ata_sff_error_handler(struct ata_port *ap)
 	ata_sff_sync(ap);		/* FIXME: We don't need this */
 	ap->ops->sff_check_status(ap);
 	ap->ops->sff_irq_clear(ap);
+	/* We *MUST* do FIFO draining before we issue a reset as several
+	 * devices helpfully clear their internal state and will lock solid
+	 * if we touch the data port post reset. Pass qc in case anyone wants
+	 *  to do different PIO/DMA recovery or has per command fixups
+	 */
+	if (ap->ops->drain_fifo)
+		ap->ops->drain_fifo(qc);
 
 	spin_unlock_irqrestore(ap->lock, flags);
 
@@ -2959,4 +3045,3 @@ out:
 EXPORT_SYMBOL_GPL(ata_pci_sff_init_one);
 
 #endif /* CONFIG_PCI */
-