From 7893d2eab16af186d630cd3834a07b9a477385b4 Mon Sep 17 00:00:00 2001 From: Marcel Ziswiler Date: Wed, 6 Jan 2016 18:27:27 +0100 Subject: PCI: Apalis GEN1 forcing quirk The Apalis evaluation board needs to set the link speed to 2.5 GT/s (GEN1). The default link speed setting is 5 GT/s (GEN2). 0x98 is the Link Control 2 PCIe Capability Register of the PEX8605 PCIe switch. The switch supports link speed auto negotiation, but falsely sets the link speed to 5 GT/s. Signed-off-by: Marcel Ziswiler Acked-by: Max Krummenacher --- drivers/pci/quirks.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 032460f2dc08..82077e4b5c72 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -2140,6 +2140,21 @@ static void quirk_tile_plx_gen1(struct pci_dev *dev) DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_PLX, 0x8624, quirk_tile_plx_gen1); #endif /* CONFIG_TILEPRO */ +#ifdef CONFIG_PCI_FORCE_GEN1 +/* + * The Apalis evaluation board needs to set the link speed to 2.5 GT/s (GEN1). + * The default link speed setting is 5 GT/s (GEN2). 0x98 is the Link Control 2 + * PCIe Capability Register of the PEX8605 PCIe switch. The switch supports + * link speed auto negotiation, but falsely sets the link speed to 5 GT/s. + */ +static void quirk_apalis_plx_gen1(struct pci_dev *dev) +{ + pci_write_config_dword(dev, 0x98, 0x1); + mdelay(50); +} +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_PLX, 0x8605, quirk_apalis_plx_gen1); +#endif /* CONFIG_PCI_FORCE_GEN1 */ + #ifdef CONFIG_PCI_MSI /* Some chipsets do not support MSI. We cannot easily rely on setting * PCI_BUS_FLAGS_NO_MSI in its bus flags because there are actually -- cgit v1.2.3