From 012081e70bc9fe335ca9132e61bbfd00979b56c4 Mon Sep 17 00:00:00 2001 From: Olof Johansson Date: Mon, 27 Jul 2020 11:11:22 -0400 Subject: [PATCH] PCI/DPC: Add "pcie_ports=dpc-native" to allow DPC without AER control task #29600094 commit 35a0b2378c199d4f26e458b2ca38ea56aaf2d9b8 upstream. Backport summary: for 4.19 kernel ICX PCIe Gen4 support. 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 (cherry picked from commit 35a0b2378c199d4f26e458b2ca38ea56aaf2d9b8) Signed-off-by: Ethan Zhao Signed-off-by: Artie Ding Acked-by: Caspar Zhang --- Documentation/admin-guide/kernel-parameters.txt | 2 ++ drivers/pci/pcie/dpc.c | 2 +- drivers/pci/pcie/portdrv.h | 2 ++ drivers/pci/pcie/portdrv_core.c | 7 ++++++- drivers/pci/pcie/portdrv_pci.c | 8 ++++++++ 5 files changed, 19 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 5587ee42ab3f..02db90ce3842 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3456,6 +3456,8 @@ 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 a32ec3487a8d..e06f42f58d3d 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 21530b029cae..8c48f9d2e540 100644 --- a/drivers/pci/pcie/portdrv.h +++ b/drivers/pci/pcie/portdrv.h @@ -26,6 +26,8 @@ #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 5e687a570a96..3689d3b53672 100644 --- a/drivers/pci/pcie/portdrv_core.c +++ b/drivers/pci/pcie/portdrv_core.c @@ -247,8 +247,13 @@ 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; return services; diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c index 6e24329710e1..a884460cbe20 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; } -- GitLab