On Thu, Jul 25, 2024 at 01:17:08PM +0530, Manivannan Sadhasivam wrote: > On Thu, Jul 25, 2024 at 10:50:13AM +0530, Siddharth Vadapalli wrote: > > 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. > > > > Since both callbacks are populated in the pci/of driver, this consistency won't > be visible in the controller drivers. From the functionality pov, setting both > callbacks to NULL is *not* required to disable INTx, right? Yes, setting 'swizzle_irq' to NULL isn't required. The execution sequence with 'swizzle_irq' set to 'pci_common_swizzle()' is as follows: pci_assign_irq() if (pin) { if (hbrg->swizzle_irq) slot = (*(hbrg->swizzle_irq))(dev, &pin); pci_common_swizzle() while (!pci_is_root_bus(dev->bus)) <= NOT entered ..continue execution similar to 'swizzle_irq' being NULL. Having 'swizzle_irq' set to 'pci_common_swizzle()' will only result in a no-op which could have been avoided by setting it to NULL. So there is no difference w.r.t. functionality. Regards, Siddharth.
