Be prudent and give some time for power and clocks to become stable. As described in the PCIe CEM specification sections 2.2 and 2.2.1; as well as PCIe r5.0, 6.6.1. Signed-off-by: Jim Quinlan <jim2101024@xxxxxxxxx> --- drivers/pci/controller/pcie-brcmstb.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c index a45ce7d61847..39b545713ba0 100644 --- a/drivers/pci/controller/pcie-brcmstb.c +++ b/drivers/pci/controller/pcie-brcmstb.c @@ -1037,8 +1037,15 @@ static int brcm_pcie_start_link(struct brcm_pcie *pcie) pcie->perst_set(pcie, 0); /* - * Give the RC/EP time to wake up, before trying to configure RC. - * Intermittently check status for link-up, up to a total of 100ms. + * Wait for 100ms after PERST# deassertion; see PCIe CEM specification + * sections 2.2, PCIe r5.0, 6.6.1. + */ + msleep(100); + + /* + * Give the RC/EP even more time to wake up, before trying to + * configure RC. Intermittently check status for link-up, up to a + * total of 100ms. */ for (i = 0; i < 100 && !brcm_pcie_link_up(pcie); i += 5) msleep(5); -- 2.17.1
