On 1/12/22 17:36, Bjorn Helgaas wrote:
On Wed, Jan 12, 2022 at 11:34:02AM +0100, Pali Rohár wrote:
On Wednesday 12 January 2022 10:42:50 Stefan Roese wrote:
From: Bharat Kumar Gogada <bharat.kumar.gogada@xxxxxxxxxx>
Platforms may have dedicated IRQ lines for PCIe services like
AER/PME etc., check for such IRQ lines.
Check if platform has any dedicated IRQ lines for PCIe
services.
Use the terminology from the spec again ("platform-specific System
Errors").
Ok.
Signed-off-by: Bharat Kumar Gogada <bharat.kumar.gogada@xxxxxxxxxx>
Signed-off-by: Stefan Roese <sr@xxxxxxx>
Tested-by: Stefan Roese <sr@xxxxxxx>
Cc: Bjorn Helgaas <helgaas@xxxxxxxxxx>
Cc: Pali Rohár <pali@xxxxxxxxxx>
Cc: Michal Simek <michal.simek@xxxxxxxxxx>
---
drivers/pci/pcie/portdrv_core.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index bda630889f95..70dd45671ed8 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -358,6 +358,14 @@ int pcie_port_device_register(struct pci_dev *dev)
}
}
+ /*
+ * Some platforms have dedicated interrupt line from root complex to
+ * interrupt controller for PCIe services like AER/PME etc., check
+ * if platform registered with any such IRQ.
+ */
+ if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
+ pci_check_platform_service_irqs(dev, irqs, capabilities);
+
In my opinion calling this hook at this stage is too late. Few lines
above is following code:
if (irq_services) {
/*
* Initialize service IRQs. Don't use service devices that
* require interrupts if there is no way to generate them.
* However, some drivers may have a polling mode (e.g.
* pciehp_poll_mode) that can be used in the absence of IRQs.
* Allow them to determine if that is to be used.
*/
status = pcie_init_service_irqs(dev, irqs, irq_services);
if (status) {
irq_services &= PCIE_PORT_SERVICE_HP;
if (!irq_services)
goto error_disable;
}
}
Function pcie_init_service_irqs() fails if "dev" does not have any
suitable interrupt. Which happens for devices / root ports without
support for standard interrupts (INTx / MSI).
I think that this new hook should have preference over
pcie_init_service_irqs() and after this new hook should be
pcie_init_service_irqs() called only for irq_services which new hook has
not filled. And if at least new hook or pcie_init_service_irqs() passes
then "error_disable" path should not be called.
I tend to agree. I expect that a host bridge will only use this new
mechanism if the standard INTx/MSI interrupts don't work.
I guess it's possible a device could use platform-specific errors for
some services and standard INTx/MSI for others, but unless we have an
example of that, I'm not sure it's worth trying to support that.
For now, I think it will be simpler to skip pcie_init_service_irqs()
completely if the platform-specific hook is successful.
Understood. I'll make the necessary changes in v3.
Thanks,
Stefan
