Re: [PATCH 1/5 V2] PCI: define a function to check and wait till port finish DPC handling

From: Christoph Hellwig
Date: Sun Sep 27 2020 - 02:24:32 EST


> +#ifdef CONFIG_PCIE_DPC
> +static inline bool pci_wait_port_outdpc(struct pci_dev *pdev)
> +{
> + u16 cap = pdev->dpc_cap, status;
> + u16 loop = 0;
> +
> + if (!cap) {
> + pci_WARN_ONCE(pdev, !cap, "No DPC capability initiated\n");
> + return false;
> + }
> + pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
> + pci_dbg(pdev, "DPC status %x, cap %x\n", status, cap);
> + while (status & PCI_EXP_DPC_STATUS_TRIGGER && loop < 100) {
> + msleep(10);
> + loop++;
> + pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
> + }
> + if (!(status & PCI_EXP_DPC_STATUS_TRIGGER)) {
> + pci_dbg(pdev, "Out of DPC %x, cost %d ms\n", status, loop*10);
> + return true;
> + }
> + pci_dbg(pdev, "Timeout to wait port out of DPC status\n");
> + return false;
> +}

I don't think that there is any good reason to have this as an
inline function.