From 914168e1846cbf35c2d0e26f7e357724d1d1f2bc Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Stefan=20M=C3=A4tje?= Date: Fri, 29 Mar 2019 18:07:35 +0100 Subject: PCI: Work around Pericom PCIe-to-PCI bridge Retrain Link erratum MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 4ec73791a64bab25cabf16a6067ee478692e506d upstream. Due to an erratum in some Pericom PCIe-to-PCI bridges in reverse mode (conventional PCI on primary side, PCIe on downstream side), the Retrain Link bit needs to be cleared manually to allow the link training to complete successfully. If it is not cleared manually, the link training is continuously restarted and no devices below the PCI-to-PCIe bridge can be accessed. That means drivers for devices below the bridge will be loaded but won't work and may even crash because the driver is only reading 0xffff. See the Pericom Errata Sheet PI7C9X111SLB_errata_rev1.2_102711.pdf for details. Devices known as affected so far are: PI7C9X110, PI7C9X111SL, PI7C9X130. Add a new flag, clear_retrain_link, in struct pci_dev. Quirks for affected devices set this bit. Note that pcie_retrain_link() lives in aspm.c because that's currently the only place we use it, but this erratum is not specific to ASPM, and we may retrain links for other reasons in the future. Signed-off-by: Stefan Mätje [bhelgaas: apply regardless of CONFIG_PCIEASPM] Signed-off-by: Bjorn Helgaas Reviewed-by: Andy Shevchenko CC: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/pci/quirks.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'drivers/pci/quirks.c') diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 541efca8db0b..45c3fbd38f50 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -2085,6 +2085,23 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x10f1, quirk_disable_aspm_l0s); DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x10f4, quirk_disable_aspm_l0s); DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x1508, quirk_disable_aspm_l0s); +/* + * Some Pericom PCIe-to-PCI bridges in reverse mode need the PCIe Retrain + * Link bit cleared after starting the link retrain process to allow this + * process to finish. + * + * Affected devices: PI7C9X110, PI7C9X111SL, PI7C9X130. See also the + * Pericom Errata Sheet PI7C9X111SLB_errata_rev1.2_102711.pdf. + */ +static void quirk_enable_clear_retrain_link(struct pci_dev *dev) +{ + dev->clear_retrain_link = 1; + pci_info(dev, "Enable PCIe Retrain Link quirk\n"); +} +DECLARE_PCI_FIXUP_HEADER(0x12d8, 0xe110, quirk_enable_clear_retrain_link); +DECLARE_PCI_FIXUP_HEADER(0x12d8, 0xe111, quirk_enable_clear_retrain_link); +DECLARE_PCI_FIXUP_HEADER(0x12d8, 0xe130, quirk_enable_clear_retrain_link); + static void fixup_rev1_53c810(struct pci_dev *dev) { u32 class = dev->class; -- cgit v1.2.3