Some of the legacy PCIe endpoints doesn't enumerate if root port advertises both Gen-1 and Gen-2 speeds. Hence, the strategy followed here is to initially advertise only Gen-1 and after link is up, retrain link to Gen-2 speed. Following two cards display this behaviour, - Fusion HDTV 5 Express card - IOGear SIL - PCIE - SATA card Signed-off-by: Manikanta Maddireddy <mmaddireddy@xxxxxxxxxx> --- drivers/pci/controller/pci-tegra.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c index 7dc728cc5f51..7e24eac12668 100644 --- a/drivers/pci/controller/pci-tegra.c +++ b/drivers/pci/controller/pci-tegra.c @@ -670,6 +670,17 @@ static void tegra_pcie_apply_sw_fixup(struct tegra_pcie_port *port) value |= soc->update_fc_val; writel(value, port->base + RP_VEND_XP); } + + /* + * PCIe link doesn't come up with few legacy PCIe endpoints + * if root port advertises both Gen-1 and Gen-2 speeds. + * Hence, the strategy followed here is to initially advertise + * only Gen-1 and after link is up, retrain link to Gen-2 speed + */ + value = readl(port->base + RP_LINK_CONTROL_STATUS_2); + value &= ~PCI_EXP_LNKSTA_CLS; + value |= PCI_EXP_LNKSTA_CLS_2_5GB; + writel(value, port->base + RP_LINK_CONTROL_STATUS_2); } static void tegra_pcie_port_enable(struct tegra_pcie_port *port) -- 2.17.1
