Re: [PATCH] PCI: j721e: Set .map_irq and .swizzle_irq to NULL

[Siddharth Vadapalli]

On Wed, Jul 24, 2024 at 09:49:16PM +0530, Manivannan Sadhasivam wrote:
> On Wed, Jul 24, 2024 at 12:20:48PM +0530, Siddharth Vadapalli wrote:
> > Since the configuration of Legacy Interrupts (INTx) is not supported, set
> > the .map_irq and .swizzle_irq callbacks to NULL. This fixes the error:
> >   of_irq_parse_pci: failed with rc=-22
> > due to the absence of Legacy Interrupts in the device-tree.
> > 
> 
> Do you really need to set 'swizzle_irq' to NULL? pci_assign_irq() will bail out
> if 'map_irq' is set to NULL.

While 'swizzle_irq' won't be invoked if 'map_irq' is NULL, having a
non-NULL 'swizzle_irq' (pci_common_swizzle in this case) with a NULL
'map_irq' seems inconsistent to me though the code-path may never invoke
it. Wouldn't a non-NULL 'swizzle_irq' imply that Legacy Interrupts are
supported, while a NULL 'map_irq' indicates that they aren't? Since they
are always described in pairs, whether it is in the initial commit that
added support for the Cadence PCIe Host controller (used by pci-j721e.c):
https://github.com/torvalds/linux/commit/1b79c5284439
OR the commit which moved the shared 'map_irq' and 'swizzle_irq' defaults
from all the host drivers into the common 'devm_of_pci_bridge_init()'
function:
https://github.com/torvalds/linux/commit/b64aa11eb2dd
I have set both of them to NULL for the sake of consistency.

Regards,
Siddharth.