On Fri, Jul 26, 2024 at 03:54:17PM +0530, Siddharth Vadapalli wrote:
On Thu, Jul 25, 2024 at 02:01:48PM +0530, Siddharth Vadapalli wrote:
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.
Mani,
I prefer setting 'swizzle_irq' to NULL as well unless you have an objection to it. Kindly let me know. I plan to post the v2 for this patch addressing Bjorn's feedback and collecting Andrew's "Tested-by" tag as well.
Ok, fine with me.
- Mani