Re: [PATCH v5 3/3] pci:aer: add support aer interrupt with none MSI/MSI-X/INTx mode

Bjorn Helgaas
2016-09-21T22:37:48Z

On Tue, Sep 13, 2016 at 12:40:59PM +0800, Po Liu wrote:
> On some platforms, root port doesn't support MSI/MSI-X/INTx in RC mode.
> When chip support the aer interrupt with none MSI/MSI-X/INTx mode,
> maybe there is interrupt line for aer pme etc. Search the interrupt
> number in the fdt file. Then fixup the dev->irq with it.
>
> Signed-off-by: Po Liu <po.liu@nxp.com>
> ---
> changes for v5:
> - Add clear 'aer' interrup-names description
>
> .../devicetree/bindings/pci/layerscape-pci.txt | 11 +++++---
> drivers/pci/pcie/portdrv_core.c | 31 +++++++++++++++++++---
> 2 files changed, 35 insertions(+), 7 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/pci/layerscape-pci.txt b/Documentation/devicetree/bindings/pci/layerscape-pci.txt
> index 41e9f55..101d0a7 100644
> --- a/Documentation/devicetree/bindings/pci/layerscape-pci.txt
> +++ b/Documentation/devicetree/bindings/pci/layerscape-pci.txt
> @@ -18,8 +18,10 @@ Required properties:
> - reg: base addresses and lengths of the PCIe controller
> - interrupts: A list of interrupt outputs of the controller. Must contain an
> entry for each entry in the interrupt-names property.
> -- interrupt-names: Must include the following entries:
> - "intr": The interrupt that is asserted for controller interrupts
> +- interrupt-names: It may be include the following entries:
> + "aer": The interrupt that is asserted for aer interrupt
> + "pme": The interrupt that is asserted for pme interrupt
> + ......
> - fsl,pcie-scfg: Must include two entries.
> The first entry must be a link to the SCFG device node
> The second entry must be '0' or '1' based on physical PCIe controller index.
> @@ -35,8 +37,9 @@ Example:
> reg = <0x00 0x03400000 0x0 0x00010000 /* controller registers */
> 0x40 0x00000000 0x0 0x00002000>; /* configuration space */
> reg-names = "regs", "config";
> - interrupts = <GIC_SPI 177 IRQ_TYPE_LEVEL_HIGH>; /* controller interrupt */
> - interrupt-names = "intr";
> + interrupts = <GIC_SPI 176 IRQ_TYPE_LEVEL_HIGH>, /* aer interrupt */
> + <GIC_SPI 177 IRQ_TYPE_LEVEL_HIGH>; /* pme interrupt */
> + interrupt-names = "aer", "pme";
> fsl,pcie-scfg = <&scfg 0>;
> #address-cells = <3>;
> #size-cells = <2>;
> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> index e9270b4..7c4943d 100644
> --- a/drivers/pci/pcie/portdrv_core.c
> +++ b/drivers/pci/pcie/portdrv_core.c
> @@ -16,6 +16,7 @@
> #include <linux/slab.h>
> #include <linux/pcieport_if.h>
> #include <linux/aer.h>
> +#include <linux/of_irq.h>
>
> #include "../pci.h"
> #include "portdrv.h"
> @@ -200,6 +201,28 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *vectors, int mask)
> static int init_service_irqs(struct pci_dev *dev, int *irqs, int mask)
> {
> int i, irq = -1;
> + int ret;
> + struct device_node *np = NULL;
> +
> + for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
> + irqs[i] = 0;
> +
> + if (dev->bus->dev.of_node)
> + np = dev->bus->dev.of_node;
> +
> + /* If root port doesn't support MSI/MSI-X/INTx in RC mode,
> + * request irq for aer
> + */
> + if (IS_ENABLED(CONFIG_OF_IRQ) && np &&
> + (mask & PCIE_PORT_SERVICE_PME)) {
> + ret = of_irq_get_byname(np, "aer");
> + if (ret > 0) {
> + irqs[PCIE_PORT_SERVICE_AER_SHIFT] = ret;
> + if (dev->irq)
> + irq = dev->irq;
> + goto no_msi;
> + }
> + }

We definitely need to solve this somehow. But this approach doesn't
feel quite right because it's hard to map this code back to anything
in the spec, and it uses a completely platform-dependent name
("interrupt-names aer") in code that is supposedly generic.

What if we added some sort of hook that would return the IRQ? Maybe a
pcibios_*() hook right now, with the idea of making it a
pci_host_bridge function pointer someday?

I know the body of the hook would look a lot like what you have here,
but at least it would be more obvious that it's platform-specific
code.

I think your platform supports PME interrupts as well as AER, and
they're different IRQs. So you'd probably have to do something
similar to the pcie_port_enable_msix() interface, so you can fill in
both IRQs.

> /*
> * If MSI cannot be used for PCIe PME or hotplug, we have to use
> @@ -225,11 +248,13 @@ static int init_service_irqs(struct pci_dev *dev, int *irqs, int mask)
> irq = dev->irq;
>
> no_msi:
> - for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
> - irqs[i] = irq;
> + for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++) {
> + if (!irqs[i])
> + irqs[i] = irq;
> + }
> irqs[PCIE_PORT_SERVICE_VC_SHIFT] = -1;
>
> - if (irq < 0)
> + if (irq < 0 && irqs[PCIE_PORT_SERVICE_AER_SHIFT] < 0)
> return -ENODEV;
> return 0;
> }
> --
> 2.1.0.27.g96db324
>
>
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