On Thu, 6 Oct 2022, Christophe Leroy wrote:
> NO_IRQ is used to check the return of irq_of_parse_and_map().
>
> On some architecture NO_IRQ is 0, on other architectures it is -1.
>
Yes. The core NCR5380 driver is used on ARM etc. where NO_IRQ is -1 as
well as on powerpc where it is 0.
> irq_of_parse_and_map() returns 0 on error, independent of NO_IRQ.
>
> So use 0 instead of using NO_IRQ.
>
Sorry, I must be missing something.
You seem to be saying that this driver could be re-used in the context of
openfirmware/device trees if it avoided using the NO_IRQ. Do I have that
right?
Or are you changing NO_IRQ semantics tree-wide for some reason explained
somewhere else?
If it is the former, shouldn't you reverse the comment in
arch/powerpc/include/asm/irq.h, which says the macro is to be used in the
way this driver (and others) use it?
If it is the latter, shouldn't you address the use of NO_IRQ in the core
NCR5380 driver rather than just this wrapper?
Moreover, wouldn't it make more sense to fix the callers of
irq_of_parse_and_map(), since they appear to be abusing the NO_IRQ macro?
For example, drivers/ata/sata_dwc_460ex.c actually does #define NO_IRQ 0
and then expects irq_of_parse_and_map() will somehow use the same value to
mean the same thing...
> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> ---
> drivers/scsi/mac_scsi.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/scsi/mac_scsi.c b/drivers/scsi/mac_scsi.c
> index 2e511697fce3..e4df2b501e8b 100644
> --- a/drivers/scsi/mac_scsi.c
> +++ b/drivers/scsi/mac_scsi.c
> @@ -478,7 +478,7 @@ static int __init mac_scsi_probe(struct platform_device *pdev)
> if (irq)
> instance->irq = irq->start;
> else
> - instance->irq = NO_IRQ;
> + instance->irq = 0;
>
> hostdata = shost_priv(instance);
> hostdata->base = pio_mem->start;
> @@ -495,7 +495,7 @@ static int __init mac_scsi_probe(struct platform_device *pdev)
> if (error)
> goto fail_init;
>
> - if (instance->irq != NO_IRQ) {
> + if (instance->irq) {
> error = request_irq(instance->irq, macscsi_intr, IRQF_SHARED,
> "NCR5380", instance);
> if (error)
> @@ -514,7 +514,7 @@ static int __init mac_scsi_probe(struct platform_device *pdev)
> return 0;
>
> fail_host:
> - if (instance->irq != NO_IRQ)
> + if (instance->irq)
> free_irq(instance->irq, instance);
> fail_irq:
> NCR5380_exit(instance);
> @@ -528,7 +528,7 @@ static int __exit mac_scsi_remove(struct platform_device *pdev)
> struct Scsi_Host *instance = platform_get_drvdata(pdev);
>
> scsi_remove_host(instance);
> - if (instance->irq != NO_IRQ)
> + if (instance->irq)
> free_irq(instance->irq, instance);
> NCR5380_exit(instance);
> scsi_host_put(instance);
>
