> -----Original Message----- > From: Fabio Estevam <festevam@xxxxxxxxx> > Sent: 2022年2月8日 18:10 > To: Hongxing Zhu <hongxing.zhu@xxxxxxx> > Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>; Bjorn Helgaas > <bhelgaas@xxxxxxxxxx>; Mark Brown <broonie@xxxxxxxxxx>; Lorenzo Pieralisi > <lorenzo.pieralisi@xxxxxxx>; Jingoo Han <jingoohan1@xxxxxxxxx>; > linux-pci@xxxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>; moderated > list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE > <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx>; linux-kernel > <linux-kernel@xxxxxxxxxxxxxxx>; Sascha Hauer <kernel@xxxxxxxxxxxxxx> > Subject: Re: [PATCH v6 7/8] PCI: imx6: Disable enabled clocks and regulators > after link is down > > Hi Richard, > > On Tue, Feb 8, 2022 at 12:57 AM Richard Zhu <hongxing.zhu@xxxxxxx> > wrote: > > > > Since i.MX PCIe doesn't support the hot-plug, and to save power > > consumption as much as possible. Return error and disable the enabled > > clocks and regulators when link is down,. > > It is OK to disable clocks and regulators, but I don't think we should return an > error on dw_pcie_wait_for_link() failure. Hi Fabio: Thanks for your review. How do we know there is a link down, if we don't return an error on the dw_pcie_wait_for_link() after host_init callback. Do you mean that we should ignore the return of dw_pcie_host_init() and finish the _probe without an error return? Best Regards Richard > > Please check: > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kern > el.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Flpieralisi%2Fpci.git%2Fco > mmit%2F%3Fh%3Dpci%2Fimx6%26id%3Df81f095e87715e198471f4653952fe > 5e3f824874&data=04%7C01%7Chongxing.zhu%40nxp.com%7C3630184 > 5833b41f1f70a08d9eaeb2519%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C > 0%7C0%7C637799117928160088%7CUnknown%7CTWFpbGZsb3d8eyJWIjoi > MC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C300 > 0&sdata=UUF%2FbZNUy7T4d89sJKnPvN6kNxEB%2FhnSUbIze7ilUOA%3D > &reserved=0 > > and > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kern > el.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Flpieralisi%2Fpci.git%2Fco > mmit%2F%3Fh%3Dpci%2Fimx6%26id%3D886a9c134755&data=04%7C0 > 1%7Chongxing.zhu%40nxp.com%7C36301845833b41f1f70a08d9eaeb2519%7 > C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63779911792816008 > 8%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiL > CJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=FO0wr4IE%2BA6YCu > f0Lal2az8FRkK8ZvHkmLM%2F5zlosZY%3D&reserved=0 > > as to why all the dwc PCI drivers should treat dw_pcie_wait_for_link() > uniformly. > > > > > > > > > > Add a new host_exit() callback for i.MX PCIe driver to disable the > > enabled clocks, regulators and so on in the error handling after > > host_init is finished. > > > > Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx> > > --- > > drivers/pci/controller/dwc/pci-imx6.c | 30 > > ++++++++++++++++++++++++--- > > 1 file changed, 27 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c > > b/drivers/pci/controller/dwc/pci-imx6.c > > index e165ad00989c..7a7d9204c6bc 100644 > > --- a/drivers/pci/controller/dwc/pci-imx6.c > > +++ b/drivers/pci/controller/dwc/pci-imx6.c > > @@ -848,7 +848,9 @@ static int imx6_pcie_start_link(struct dw_pcie *pci) > > /* Start LTSSM. */ > > imx6_pcie_ltssm_enable(dev); > > > > - dw_pcie_wait_for_link(pci); > > + ret = dw_pcie_wait_for_link(pci); > > + if (ret) > > + goto err_reset_phy; > > > > if (pci->link_gen == 2) { > > /* Allow Gen2 mode after the link is up. */ @@ -884,7 > > +886,9 @@ static int imx6_pcie_start_link(struct dw_pcie *pci) > > } > > > > /* Make sure link training is finished as well! */ > > - dw_pcie_wait_for_link(pci); > > + ret = dw_pcie_wait_for_link(pci); > > + if (ret) > > + goto err_reset_phy; > > } else { > > dev_info(dev, "Link: Gen2 disabled\n"); > > } > > @@ -897,7 +901,6 @@ static int imx6_pcie_start_link(struct dw_pcie *pci) > > dev_dbg(dev, "PHY DEBUG_R0=0x%08x DEBUG_R1=0x%08x\n", > > dw_pcie_readl_dbi(pci, PCIE_PORT_DEBUG0), > > dw_pcie_readl_dbi(pci, PCIE_PORT_DEBUG1)); > > - imx6_pcie_reset_phy(imx6_pcie); > > return ret; > > } > > > > @@ -921,8 +924,29 @@ static int imx6_pcie_host_init(struct pcie_port *pp) > > return 0; > > } > > > > +static void imx6_pcie_host_exit(struct pcie_port *pp) { > > + struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > > + struct device *dev = pci->dev; > > + struct imx6_pcie *imx6_pcie = to_imx6_pcie(pci); > > + > > + imx6_pcie_reset_phy(imx6_pcie); > > + imx6_pcie_clk_disable(imx6_pcie); > > + switch (imx6_pcie->drvdata->variant) { > > + case IMX8MM: > > + if (phy_power_off(imx6_pcie->phy)) > > + dev_err(dev, "unable to power off phy\n"); > > + break; > > + default: > > + break; > > + } > > + if (imx6_pcie->vpcie) > > + regulator_disable(imx6_pcie->vpcie); > > +} > > + > > static const struct dw_pcie_host_ops imx6_pcie_host_ops = { > > .host_init = imx6_pcie_host_init, > > + .host_exit = imx6_pcie_host_exit, > > }; > > > > static const struct dw_pcie_ops dw_pcie_ops = { > > -- > > 2.25.1 > >
