Le 06/10/2022 à 11:25, Finn Thain a écrit : > 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. My mistake. I started by removing NO_IRQ definition in powerpc and then fixed all build failures by replacing NO_IRQ by 0. Then I splitted the patch into one per subsystem, all with the same explaination. Most places it was just a verification of the value returned by irq_of_parse_and_map() where it is obviously wrong to use NO_IRQ, especially on ARM where NO_IRQ doesn't match what irq_of_parse_and_map() returns in case on error. But here in the mac_scsi driver it seems a bit different and I have a look more closely. > > 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? No, I only say that NO_IRQ doesn't match the value returned by irq_of_parse_and_map(). Ultimately I want to remove the #define NO_IRQ from arch/powerpc/include/asm/irq.h That's to be linked to following message from Linus : https://lkml.org/lkml/2005/11/21/221 > > 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? Yes I guess so. > > 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? Indeed. That's what is being done most places. > > 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... It didn't pop up during the multi-build I did for powerpc, so I guess that driver is not used for powerpc ? In the ata subsystem I fixed pata_mpc52xx. Thanks Christophe
