[PATCH/RFC 2/9] libata: add irq_off() for symmetry

[Albert Lee <albertcc@tw.ibm.com>]

Patch 2/9:
  Currently there is irq_on() but no irq_off().
Turning irq off is done via altering the nIEN bit of qc->tf, together with tf_load().
This patch adds irq_off() for symmetry.
tf_load() and ata_qc_set_polling() will be fixed/removed in later patches.

Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
---

diff -Nrup 01_remove_leftover_irqon/drivers/ata/libata-core.c 02_add_irq_off/drivers/ata/libata-core.c
--- 01_remove_leftover_irqon/drivers/ata/libata-core.c	2007-06-11 17:31:53.000000000 +0800
+++ 02_add_irq_off/drivers/ata/libata-core.c	2007-06-12 13:20:05.000000000 +0800
@@ -6906,6 +6906,8 @@ EXPORT_SYMBOL_GPL(ata_eh_qc_retry);
 EXPORT_SYMBOL_GPL(ata_do_eh);
 EXPORT_SYMBOL_GPL(ata_irq_on);
 EXPORT_SYMBOL_GPL(ata_dummy_irq_on);
+EXPORT_SYMBOL_GPL(ata_irq_off);
+EXPORT_SYMBOL_GPL(ata_dummy_irq_off);
 EXPORT_SYMBOL_GPL(ata_irq_ack);
 EXPORT_SYMBOL_GPL(ata_dummy_irq_ack);
 EXPORT_SYMBOL_GPL(ata_dev_try_classify);
diff -Nrup 01_remove_leftover_irqon/drivers/ata/libata-sff.c 02_add_irq_off/drivers/ata/libata-sff.c
--- 01_remove_leftover_irqon/drivers/ata/libata-sff.c	2007-06-01 12:08:21.000000000 +0800
+++ 02_add_irq_off/drivers/ata/libata-sff.c	2007-06-12 13:19:27.000000000 +0800
@@ -67,6 +67,39 @@ u8 ata_irq_on(struct ata_port *ap)
 u8 ata_dummy_irq_on (struct ata_port *ap) 	{ return 0; }
 
 /**
+ *	ata_irq_off - Disable interrupts on a port.
+ *	@ap: Port on which interrupts are disabled.
+ *
+ *	Disable interrupts on a legacy IDE device using MMIO or PIO,
+ *	wait for idle, clear any pending interrupts.
+ *
+ *	LOCKING:
+ *	Inherited from caller.
+ */
+u8 ata_irq_off(struct ata_port *ap)
+{
+	struct ata_ioports *ioaddr = &ap->ioaddr;
+	u8 tmp;
+
+	ap->ctl |= ATA_NIEN;
+	ap->last_ctl = ap->ctl;
+
+	iowrite8(ap->ctl, ioaddr->ctl_addr);
+
+	/* Under certain circumstances, some controllers raise IRQ on
+	 * ATA_NIEN manipulation.  Also, many controllers fail to mask
+	 * previously pending IRQ on ATA_NIEN assertion.  Clear it.
+	 */
+	tmp = ata_wait_idle(ap);
+
+	ap->ops->irq_clear(ap);
+
+	return tmp;
+}
+
+u8 ata_dummy_irq_off (struct ata_port *ap) 	{ return 0; }
+
+/**
  *	ata_irq_ack - Acknowledge a device interrupt.
  *	@ap: Port on which interrupts are enabled.
  *
diff -Nrup 01_remove_leftover_irqon/drivers/ata/libata.h 02_add_irq_off/drivers/ata/libata.h
--- 01_remove_leftover_irqon/drivers/ata/libata.h	2007-06-01 12:08:21.000000000 +0800
+++ 02_add_irq_off/drivers/ata/libata.h	2007-06-12 13:20:23.000000000 +0800
@@ -156,7 +156,5 @@ extern void ata_port_wait_eh(struct ata_
 extern void ata_qc_schedule_eh(struct ata_queued_cmd *qc);
 
 /* libata-sff.c */
-extern u8 ata_irq_on(struct ata_port *ap);
-
 
 #endif /* __LIBATA_H__ */
diff -Nrup 01_remove_leftover_irqon/include/linux/libata.h 02_add_irq_off/include/linux/libata.h
--- 01_remove_leftover_irqon/include/linux/libata.h	2007-06-01 12:08:32.000000000 +0800
+++ 02_add_irq_off/include/linux/libata.h	2007-06-12 13:43:50.000000000 +0800
@@ -599,6 +599,7 @@ struct ata_port_operations {
 	irq_handler_t irq_handler;
 	void (*irq_clear) (struct ata_port *);
 	u8 (*irq_on) (struct ata_port *);
+	u8 (*irq_off) (struct ata_port *);
 	u8 (*irq_ack) (struct ata_port *ap, unsigned int chk_drq);
 
 	u32 (*scr_read) (struct ata_port *ap, unsigned int sc_reg);
@@ -805,6 +806,8 @@ extern struct ata_device *ata_dev_pair(s
 extern int ata_do_set_mode(struct ata_port *ap, struct ata_device **r_failed_dev);
 extern u8 ata_irq_on(struct ata_port *ap);
 extern u8 ata_dummy_irq_on(struct ata_port *ap);
+extern u8 ata_irq_off(struct ata_port *ap);
+extern u8 ata_dummy_irq_off(struct ata_port *ap);
 extern u8 ata_irq_ack(struct ata_port *ap, unsigned int chk_drq);
 extern u8 ata_dummy_irq_ack(struct ata_port *ap, unsigned int chk_drq);