The PCI Express Base Specification r6.0, section 6.6.1, states that the host should wait for at least 100 msec from the end of a conventional reset (PERST# is de-asserted) before sending a configuration request to ensure that the device is able to respond with a "Request Retry Status" completion. Add the PCIE_T_RRS_READY_MS macro to define this wait time and modify rockchip_pcie_host_init_port() to add this 100ms sleep after deasserting PERST# using the ep_gpio GPIO. Suggested-by: Bjorn Helgaas <helgaas@xxxxxxxxxx> Signed-off-by: Damien Le Moal <dlemoal@xxxxxxxxxx> --- drivers/pci/controller/pcie-rockchip-host.c | 2 ++ drivers/pci/pci.h | 7 +++++++ 2 files changed, 9 insertions(+) diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c index fc868251e570..cbec71114825 100644 --- a/drivers/pci/controller/pcie-rockchip-host.c +++ b/drivers/pci/controller/pcie-rockchip-host.c @@ -325,6 +325,8 @@ static int rockchip_pcie_host_init_port(struct rockchip_pcie *rockchip) msleep(PCIE_T_PVPERL_MS); gpiod_set_value_cansleep(rockchip->ep_gpio, 1); + msleep(PCIE_T_RRS_READY_MS); + /* 500ms timeout value should be enough for Gen1/2 training */ err = readl_poll_timeout(rockchip->apb_base + PCIE_CLIENT_BASIC_STATUS1, status, PCIE_LINK_UP(status), 20, diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 17fed1846847..c93ffc5e6e1f 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -16,6 +16,13 @@ /* Power stable to PERST# inactive from PCIe card Electromechanical Spec */ #define PCIE_T_PVPERL_MS 100 +/* + * End of conventional reset (PERST# de-asserted) to first configuration + * request (device able to respond with a "Request Retry Status" completion), + * from PCI Express Base Specification r6.0, section 6.6.1. + */ +#define PCIE_T_RRS_READY_MS 100 + /* * PCIe r6.0, sec 5.3.3.2.1 <PME Synchronization> * Recommends 1ms to 10ms timeout to check L2 ready. -- 2.44.0
