According to PCI Express Card Electromechanical Specification Revision 3.0, Table 2-4, power stable and reference clk stable before PERST# inactive should be at least 100ms and 100us respectively. Otherwise we do see some failures for link training. Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx> --- drivers/pci/controller/pcie-rockchip-host.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c index 94af6f5..2f4d909 100644 --- a/drivers/pci/controller/pcie-rockchip-host.c +++ b/drivers/pci/controller/pcie-rockchip-host.c @@ -331,6 +331,14 @@ static int rockchip_pcie_host_init_port(struct rockchip_pcie *rockchip) rockchip_pcie_write(rockchip, PCIE_CLIENT_LINK_TRAIN_ENABLE, PCIE_CLIENT_CONFIG); + /* + * According to PCI Express Card Electromechanical Specification + * Revision 3.0, Table 2-4, power stable and reference clk stable + * before PERST# inactive should be at least 100ms and 100us + * respectively. Otherwise we do see some failures for link training. + */ + msleep(100); + gpiod_set_value_cansleep(rockchip->ep_gpio, 1); /* 500ms timeout value should be enough for Gen1/2 training */ -- 2.7.4 _______________________________________________ Linux-rockchip mailing list Linux-rockchip@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/linux-rockchip
