ncr5380: Fix SCSI_IRQ_NONE bugs

Oak scsi doesn't use any IRQ, but it sets irq = IRQ_NONE rather than
SCSI_IRQ_NONE. Problem is, the core NCR5380 driver expects SCSI_IRQ_NONE
if it is to issue IDENTIFY commands that prevent target disconnection.
And, as Geert points out, IRQ_NONE is part of enum irqreturn.

Other drivers, when they can't get an IRQ or can't use one, will set
host->irq = SCSI_IRQ_NONE (that is, 255). But when they exit they will
attempt to free IRQ 255 which was never requested.

Fix these bugs by using NO_IRQ in place of SCSI_IRQ_NONE and IRQ_NONE.
That means IRQ 0 is no longer probed by ISA drivers but I don't think
this matters.

Setting IRQ = 255 for these ISA drivers is understood to mean no IRQ.
This remains supported so as to avoid breaking existing ISA setups (which
can be difficult to get working) and because existing documentation
(SANE, TLDP etc) describes this usage for the ISA NCR5380 driver options.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 11 insertions, 9 deletions

diff --git a/drivers/scsi/pas16.c b/drivers/scsi/pas16.c
index 3e40479ebb48..3782091f82cb 100644
--- a/drivers/scsi/pas16.c
+++ b/drivers/scsi/pas16.c
@@ -62,13 +62,11 @@
  *   If you have problems with your card not being recognized, use
  *   the LILO command line override.  Try to get it recognized without
  *   interrupts.  Ie, for a board at the default 0x388 base port,
- *   boot: linux pas16=0x388,255
+ *   boot: linux pas16=0x388,0
  *
- *   SCSI_IRQ_NONE (255) should be specified for no interrupt,
+ *   NO_IRQ (0) should be specified for no interrupt,
  *   IRQ_AUTO (254) to autoprobe for an IRQ line if overridden
  *   on the command line.
- *
- *   (IRQ_AUTO == 254, SCSI_IRQ_NONE == 255 in NCR5380.h)
  */
  
 #include <linux/module.h>
@@ -416,15 +414,19 @@ static int __init pas16_detect(struct scsi_host_template *tpnt)
 	else 
 	    instance->irq = NCR5380_probe_irq(instance, PAS16_IRQS);
 
-	if (instance->irq != SCSI_IRQ_NONE) 
+	/* Compatibility with documented NCR5380 kernel parameters */
+	if (instance->irq == 255)
+		instance->irq = NO_IRQ;
+
+	if (instance->irq != NO_IRQ)
 	    if (request_irq(instance->irq, pas16_intr, 0,
 			    "pas16", instance)) {
 		printk("scsi%d : IRQ%d not free, interrupts disabled\n", 
 		    instance->host_no, instance->irq);
-		instance->irq = SCSI_IRQ_NONE;
+		instance->irq = NO_IRQ;
 	    } 
 
-	if (instance->irq == SCSI_IRQ_NONE) {
+	if (instance->irq == NO_IRQ) {
 	    printk("scsi%d : interrupts not enabled. for better interactive performance,\n", instance->host_no);
 	    printk("scsi%d : please jumper the board for a free IRQ.\n", instance->host_no);
 	    /* Disable 5380 interrupts, leave drive params the same */
@@ -438,7 +440,7 @@ static int __init pas16_detect(struct scsi_host_template *tpnt)
 
 	printk("scsi%d : at 0x%04x", instance->host_no, (int) 
 	    instance->io_port);
-	if (instance->irq == SCSI_IRQ_NONE)
+	if (instance->irq == NO_IRQ)
 	    printk (" interrupts disabled");
 	else 
 	    printk (" irq %d", instance->irq);
@@ -568,7 +570,7 @@ static inline int NCR5380_pwrite (struct Scsi_Host *instance, unsigned char *src
 
 static int pas16_release(struct Scsi_Host *shost)
 {
-	if (shost->irq)
+	if (shost->irq != NO_IRQ)
 		free_irq(shost->irq, shost);
 	NCR5380_exit(shost);
 	if (shost->io_port && shost->n_io_port)