From 4ec73791a64bab25cabf16a6067ee478692e506d Mon Sep 17 00:00:00 2001 From: Stefan Mätje 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 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 --- include/linux/pci.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/pci.h b/include/linux/pci.h index 77448215ef5b..2c056a7a728a 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -348,6 +348,8 @@ struct pci_dev { unsigned int hotplug_user_indicators:1; /* SlotCtl indicators controlled exclusively by user sysfs */ + unsigned int clear_retrain_link:1; /* Need to clear Retrain Link + bit manually */ unsigned int d3_delay; /* D3->D0 transition time in ms */ unsigned int d3cold_delay; /* D3cold->D0 transition time in ms */ -- cgit