Hi Richard, On Fri, Oct 24, 2014 at 12:36 AM, Richard Zhu <richard.zhu@xxxxxxxxxxxxx> wrote: > From: Richard Zhu <r65037@xxxxxxxxxxxxx> > > For boards without a reset GPIO we skip the delay between enabling the > pcie_ref_clk and touching the RC registers for configuration. > This hangs the system if there isn't a proper delay to ensure the clocks > are settled in the DW PCIe core. > > Also iMX6Q always needs an additional 10us delay to make sure the reset > is propagated through the core, as we don't have an explicitly > controlled reset input on this SoC. > > Signed-off-by: Richard Zhu <richard.zhu@xxxxxxxxxxxxx> > Tested-by: Tim Harvey <tharvey@xxxxxxxxxxxxx> > Tested-by: Fabio Estevam <fabio.estevam@xxxxxxxxxxxxx> > Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx> Please always add Bjorn on Cc. > --- > drivers/pci/host/pci-imx6.c | 13 ++++++++++--- > 1 file changed, 10 insertions(+), 3 deletions(-) > > diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c > index 233fe8a..eac96fb 100644 > --- a/drivers/pci/host/pci-imx6.c > +++ b/drivers/pci/host/pci-imx6.c > @@ -275,15 +275,22 @@ static int imx6_pcie_deassert_core_reset(struct pcie_port *pp) > goto err_pcie; > } > > - /* allow the clocks to stabilize */ > - usleep_range(200, 500); > - > /* power up core phy and enable ref clock */ > regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, > IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18); > + /* > + * the async reset input need ref clock to sync internally, > + * when the ref clock comes after reset, internal synced > + * reset time is too short , cannot meet the requirement. > + * add one ~10us delay here. > + */ > + udelay(10); The patch that myself and Tim has given a Tested-by tag did not contain this udelay: http://www.spinics.net/lists/linux-pci/msg34748.html In your original patch it only moved the the usleep range and that's the version that Tim has run intensive boot tests over temperature, so I would prefer that you re-send a patch like the original one. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
