Re: [PATCH 2/2] aer: add support aer interrupt with none MSI/MSI-X/INTx mode

Bjorn Helgaas
2016-06-02T03:48:36Z

[+cc Rob]

Hi Po,

On Thu, May 26, 2016 at 02:00:06PM +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.

My understanding is that AER interrupt signaling can be done via INTx,
MSI, or MSI-X (PCIe spec r3.0, sec 6.2.4.1.2). Apparently your device
doesn't support MSI or MSI-X. Are you saying it doesn't support INTx
either? How is the interrupt you're requesting here different from
INTx?

My guess is that your device *does* support INTx, and we should use
that. ACPI has the generic _PRT that describes INTx routing. There
must be something similar for DT, but I don't know what it is. It
seems like this should be described using that DT mechanism (whatever
it is), and we shouldn't need special-case code in the portdrv code.

> Signed-off-by: Po Liu <po.liu@nxp.com>
> ---
> drivers/pci/pcie/portdrv_core.c | 31 ++++++++++++++++++++++++++++---
> 1 file changed, 28 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> index 32d4d0a..64833e5 100644
> --- a/drivers/pci/pcie/portdrv_core.c
> +++ b/drivers/pci/pcie/portdrv_core.c
> @@ -15,6 +15,7 @@
> #include <linux/slab.h>
> #include <linux/pcieport_if.h>
> #include <linux/aer.h>
> +#include <linux/of_irq.h>
>
> #include "../pci.h"
> #include "portdrv.h"
> @@ -199,6 +200,28 @@ 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;
> + }
> + }
>
> /*
> * If MSI cannot be used for PCIe PME or hotplug, we have to use
> @@ -224,11 +247,13 @@ 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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