From: Olof Johansson Date: Wed, 23 Oct 2019 19:22:05 +0000 (-0700) Subject: PCI/DPC: Add "pcie_ports=dpc-native" to allow DPC without AER control X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=35a0b2378c199d4f26e458b2ca38ea56aaf2d9b8;p=linux.git PCI/DPC: Add "pcie_ports=dpc-native" to allow DPC without AER control Prior to eed85ff4c0da7 ("PCI/DPC: Enable DPC only if AER is available"), Linux handled DPC events regardless of whether firmware had granted it ownership of AER or DPC, e.g., via _OSC. PCIe r5.0, sec 6.2.10, recommends that the OS link control of DPC to control of AER, so after eed85ff4c0da7, Linux handles DPC events only if it has control of AER. On platforms that do not grant OS control of AER via _OSC, Linux DPC handling worked before eed85ff4c0da7 but not after. To make Linux DPC handling work on those platforms the same way they did before, add a "pcie_ports=dpc-native" kernel parameter that makes Linux handle DPC events regardless of whether it has control of AER. [bhelgaas: commit log, move pcie_ports_dpc_native to drivers/pci/] Link: https://lore.kernel.org/r/20191023192205.97024-1-olof@lixom.net Signed-off-by: Olof Johansson Signed-off-by: Bjorn Helgaas --- diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index c7ac2f3ac99fd..806c89f79be8e 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3540,6 +3540,8 @@ even if the platform doesn't give the OS permission to use them. This may cause conflicts if the platform also tries to use these services. + dpc-native Use native PCIe service for DPC only. May + cause conflicts if firmware uses AER or DPC. compat Disable native PCIe services (PME, AER, DPC, PCIe hotplug). diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c index a32ec3487a8d0..e06f42f58d3d4 100644 --- a/drivers/pci/pcie/dpc.c +++ b/drivers/pci/pcie/dpc.c @@ -291,7 +291,7 @@ static int dpc_probe(struct pcie_device *dev) int status; u16 ctl, cap; - if (pcie_aer_get_firmware_first(pdev)) + if (pcie_aer_get_firmware_first(pdev) && !pcie_ports_dpc_native) return -ENOTSUPP; dpc = devm_kzalloc(device, sizeof(*dpc), GFP_KERNEL); diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h index 944827a8c7d36..1e673619b101d 100644 --- a/drivers/pci/pcie/portdrv.h +++ b/drivers/pci/pcie/portdrv.h @@ -25,6 +25,8 @@ #define PCIE_PORT_DEVICE_MAXSERVICES 5 +extern bool pcie_ports_dpc_native; + #ifdef CONFIG_PCIEAER int pcie_aer_init(void); #else diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c index 1b330129089fe..5075cb9e850c5 100644 --- a/drivers/pci/pcie/portdrv_core.c +++ b/drivers/pci/pcie/portdrv_core.c @@ -250,8 +250,13 @@ static int get_port_device_capability(struct pci_dev *dev) pcie_pme_interrupt_enable(dev, false); } + /* + * With dpc-native, allow Linux to use DPC even if it doesn't have + * permission to use AER. + */ if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) && - pci_aer_available() && services & PCIE_PORT_SERVICE_AER) + pci_aer_available() && + (pcie_ports_dpc_native || (services & PCIE_PORT_SERVICE_AER))) services |= PCIE_PORT_SERVICE_DPC; if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM || diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c index 0a87091a0800e..160d67c593105 100644 --- a/drivers/pci/pcie/portdrv_pci.c +++ b/drivers/pci/pcie/portdrv_pci.c @@ -29,12 +29,20 @@ bool pcie_ports_disabled; */ bool pcie_ports_native; +/* + * If the user specified "pcie_ports=dpc-native", use the Linux DPC PCIe + * service even if the platform hasn't given us permission. + */ +bool pcie_ports_dpc_native; + static int __init pcie_port_setup(char *str) { if (!strncmp(str, "compat", 6)) pcie_ports_disabled = true; else if (!strncmp(str, "native", 6)) pcie_ports_native = true; + else if (!strncmp(str, "dpc-native", 10)) + pcie_ports_dpc_native = true; return 1; }