Re: [PATCH 4/4] PCI: xilinx-nwl: Add method to setup_platform_service_irq hook

From: Bjorn Helgaas
Date: Tue Sep 04 2018 - 09:49:03 EST


On Fri, Aug 10, 2018 at 09:09:40PM +0530, Bharat Kumar Gogada wrote:
> Add nwl_setup_service_irqs hook to setup_platform_service_irq IRQs to
> register platform provided IRQ number to kernel AER service.
>
> Signed-off-by: Bharat Kumar Gogada <bharat.kumar.gogada@xxxxxxxxxx>
> ---
> drivers/pci/controller/pcie-xilinx-nwl.c | 16 ++++++++++++++++
> 1 files changed, 16 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/pci/controller/pcie-xilinx-nwl.c b/drivers/pci/controller/pcie-xilinx-nwl.c
> index fb32840..285647b 100644
> --- a/drivers/pci/controller/pcie-xilinx-nwl.c
> +++ b/drivers/pci/controller/pcie-xilinx-nwl.c
> @@ -22,6 +22,7 @@
> #include <linux/irqchip/chained_irq.h>
>
> #include "../pci.h"
> +#include "../pcie/portdrv.h"
>
> /* Bridge core config registers */
> #define BRCFG_PCIE_RX0 0x00000000
> @@ -819,6 +820,20 @@ static int nwl_pcie_parse_dt(struct nwl_pcie *pcie,
> return 0;
> }
>
> +int nwl_setup_service_irqs(struct pci_host_bridge *bridge, int *irqs,
> + int plat_mask)
> +{
> + struct nwl_pcie *pcie;
> +
> + pcie = pci_host_bridge_priv(bridge);
> + if (plat_mask & PCIE_PORT_SERVICE_AER) {
> + irqs[PCIE_PORT_SERVICE_AER_SHIFT] = pcie->irq_misc;
> + plat_mask &= ~(1 << PCIE_PORT_SERVICE_AER_SHIFT);
> + }

If I understand correctly, this ultimately results in pcie->irq_misc
being hooked up to aer_irq() via the aer_probe() path. We already
have pcie->irq_misc being hooked up to nwl_pcie_misc_handler() via
nwl_pcie_bridge_init().

We can't rely on the ordering of the two handlers. Is it safe if
nwl_pcie_misc_handler() runs first, followed by aer_irq()? It looks
like nwl_pcie_misc_handler() might log messages and clear AER-related
errors. If that's the case aer_irq() might not find anything to do.

> +
> + return plat_mask;
> +}
> +
> static const struct of_device_id nwl_pcie_of_match[] = {
> { .compatible = "xlnx,nwl-pcie-2.11", },
> {}
> @@ -880,6 +895,7 @@ static int nwl_pcie_probe(struct platform_device *pdev)
> bridge->ops = &nwl_pcie_ops;
> bridge->map_irq = of_irq_parse_and_map_pci;
> bridge->swizzle_irq = pci_common_swizzle;
> + bridge->setup_platform_service_irq = nwl_setup_service_irqs;
>
> if (IS_ENABLED(CONFIG_PCI_MSI)) {
> err = nwl_pcie_enable_msi(pcie);
> --
> 1.7.1
>