> -----Original Message----- > From: Bjorn Helgaas <helgaas@xxxxxxxxxx> > Sent: 2022年6月28日 23:51 > To: Hongxing Zhu <hongxing.zhu@xxxxxxx> > Cc: l.stach@xxxxxxxxxxxxxx; bhelgaas@xxxxxxxxxx; robh+dt@xxxxxxxxxx; > broonie@xxxxxxxxxx; lorenzo.pieralisi@xxxxxxx; festevam@xxxxxxxxx; > francesco.dolcini@xxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > kernel@xxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx> > Subject: Re: [PATCH v13 10/15] PCI: imx6: Turn off regulator when system is in > suspend mode > > On Tue, Jun 28, 2022 at 03:48:01AM +0000, Hongxing Zhu wrote: > > > -----Original Message----- > > > From: Bjorn Helgaas <helgaas@xxxxxxxxxx> > > > Sent: 2022年6月28日 3:52 > > > To: Hongxing Zhu <hongxing.zhu@xxxxxxx> > > > Cc: l.stach@xxxxxxxxxxxxxx; bhelgaas@xxxxxxxxxx; robh+dt@xxxxxxxxxx; > > > broonie@xxxxxxxxxx; lorenzo.pieralisi@xxxxxxx; festevam@xxxxxxxxx; > > > francesco.dolcini@xxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; > > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > > > kernel@xxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx> > > > Subject: Re: [PATCH v13 10/15] PCI: imx6: Turn off regulator when > > > system is in suspend mode > > > > > > On Fri, Jun 24, 2022 at 05:05:00AM +0000, Hongxing Zhu wrote: > > > > > -----Original Message----- > > > > > From: Bjorn Helgaas <helgaas@xxxxxxxxxx> > > > > > Sent: 2022年6月24日 6:20 > > > > > To: Hongxing Zhu <hongxing.zhu@xxxxxxx> > > > > > Cc: l.stach@xxxxxxxxxxxxxx; bhelgaas@xxxxxxxxxx; > > > > > robh+dt@xxxxxxxxxx; broonie@xxxxxxxxxx; > > > > > lorenzo.pieralisi@xxxxxxx; festevam@xxxxxxxxx; > > > > > francesco.dolcini@xxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; > > > > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > > > > > linux-kernel@xxxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; > > > > > dl-linux-imx <linux-imx@xxxxxxx> > > > > > Subject: Re: [PATCH v13 10/15] PCI: imx6: Turn off regulator > > > > > when system is in suspend mode > > > > > > > > > > On Fri, Jun 17, 2022 at 06:31:09PM +0800, Richard Zhu wrote: > > > > > > The driver should undo any enables it did itself. The > > > > > > regulator disable shouldn't be basing decisions on > regulator_is_enabled(). > > > > > > > > > > > > Move the regulator_disable to the suspend function, turn off > > > > > > regulator when the system is in suspend mode. > > > > > > > > > > > > To keep the balance of the regulator usage counter, disable > > > > > > the regulator in shutdown. > > > > > > > > > > > > Link: > > > > > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2 > > > > > > F%2F > > > > > > lore > > > > > > .kernel.org%2Fr%2F1655189942-12678-6-git-send-email-hongxing.z > > > > > > &am > > > p > > > > > > ;d > > > > > at > > > > > > > > > > > > > > > a=05%7C01%7Chongxing.zhu%40nxp.com%7C5633fa1bf3c443e203e108da55 > > > > > 667dc2% > > > > > > > > > > > > > > > 7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6379161959277276 > > > > > 04%7CUnkn > > > > > > > > > > > > > > > own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1 > > > > > haWwi > > > > > > > > > > > > > > > LCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=1Kbzn3XSVvt3gGPrEy%2 > > > > > BET8EZn4I > > > > > > dwS%2BhUZ3AalZ2YZ0%3D&reserved=0 > > > > > > hu@xxxxxxx > > > > > > Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx> > > > > > > Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > > > > > > --- > > > > > > drivers/pci/controller/dwc/pci-imx6.c | 19 > > > > > > +++++++------------ > > > > > > 1 file changed, 7 insertions(+), 12 deletions(-) > > > > > > > > > > > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c > > > > > > b/drivers/pci/controller/dwc/pci-imx6.c > > > > > > index 2b42c37f1617..f72eb609769b 100644 > > > > > > --- a/drivers/pci/controller/dwc/pci-imx6.c > > > > > > +++ b/drivers/pci/controller/dwc/pci-imx6.c > > > > > > @@ -670,8 +670,6 @@ static void imx6_pcie_clk_disable(struct > > > > > > imx6_pcie > > > > > > *imx6_pcie) > > > > > > > > > > > > static void imx6_pcie_assert_core_reset(struct imx6_pcie > > > > > > *imx6_pcie) { > > > > > > - struct device *dev = imx6_pcie->pci->dev; > > > > > > - > > > > > > switch (imx6_pcie->drvdata->variant) { > > > > > > case IMX7D: > > > > > > case IMX8MQ: > > > > > > @@ -702,14 +700,6 @@ static void > > > > > > imx6_pcie_assert_core_reset(struct > > > > > imx6_pcie *imx6_pcie) > > > > > > break; > > > > > > } > > > > > > > > > > > > - if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) > > > { > > > > > > - int ret = regulator_disable(imx6_pcie->vpcie); > > > > > > - > > > > > > - if (ret) > > > > > > - dev_err(dev, "failed to disable vpcie regulator: %d\n", > > > > > > - ret); > > > > > > - } > > > > > > - > > > > > > /* Some boards don't have PCIe reset GPIO. */ > > > > > > if (gpio_is_valid(imx6_pcie->reset_gpio)) > > > > > > gpio_set_value_cansleep(imx6_pcie->reset_gpio, > > > > > > @@ -722,7 +712,7 @@ static int > > > > > > imx6_pcie_deassert_core_reset(struct > > > > > imx6_pcie *imx6_pcie) > > > > > > struct device *dev = pci->dev; > > > > > > int ret; > > > > > > > > > > > > - if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie->vpcie)) { > > > > > > + if (imx6_pcie->vpcie) { > > > > > > ret = regulator_enable(imx6_pcie->vpcie); > > > > > > if (ret) { > > > > > > dev_err(dev, "failed to enable vpcie regulator: %d\n", > @@ > > > > > -795,7 > > > > > > +785,7 @@ static int imx6_pcie_deassert_core_reset(struct > > > > > > +imx6_pcie > > > > > *imx6_pcie) > > > > > > return 0; > > > > > > > > > > > > err_clks: > > > > > > - if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) > > > { > > > > > > + if (imx6_pcie->vpcie) { > > > > > > ret = regulator_disable(imx6_pcie->vpcie); > > > > > > if (ret) > > > > > > dev_err(dev, "failed to disable vpcie regulator: %d\n", > @@ > > > > > -1022,6 > > > > > > +1012,9 @@ static int imx6_pcie_suspend_noirq(struct device > > > > > > +*dev) > > > > > > break; > > > > > > } > > > > > > > > > > > > + if (imx6_pcie->vpcie) > > > > > > + regulator_disable(imx6_pcie->vpcie); > > > > > > + > > > > > > return 0; > > > > > > } > > > > > > > > > > The suspend and resume methods should be symmetric, and they > > > > > should > > > > > *look* symmetric. > > > > > > > > > > imx6_pcie_suspend_noirq() disables the regulator, so > > > > > imx6_pcie_resume_noirq() should enable it. > > > > > > > > > > imx6_pcie_suspend_noirq() calls imx6_pcie_clk_disable() to > > > > > disable several clocks. imx6_pcie_resume_noirq() should call > > > > > imx6_pcie_clk_enable() to enable them. > > > > > > > > > > imx6_pcie_clk_enable() *is* called in the resume path, but it's > > > > > buried inside imx6_pcie_host_init() and > > > > > imx6_pcie_deassert_core_reset(). That makes it hard to analyze. > > > > > > > > > > We should be able to look at imx6_pcie_suspend_noirq() and > > > > > imx6_pcie_resume_noirq() and easily see that the resume path > > > > > resumes everything that was suspended in the suspend path. > > > > > > > > Yes, it is. It's better to keep suspend/resume symmetric as much > > > > as possible. In resume, the host_init is invoked, clocks, > > > > regulators and so on would be initialized properly. > > > > > > > > Unfortunately, there is no according host_exit() that can be > > > > called to do the reversed clocks, regulators disable operations in the > suspend. > > > > So, the clocks and regulator disable are explicitly invoked in > > > > suspend callback. > > > > > > > > How about to do the incremental updates if the .host_exit can be > > > > added later? > > > > > > This doesn't seem very convincing because everything here is in the > > > imx6 domain. The only DWC core thing here is the dw_pcie_setup_rc() > > > called in imx6_pcie_resume_noirq(), and it doesn't call back to any > > > imx6 code. > > > > > > So you should be able to make an imx6_pcie_host_exit() or whatever > > > that corresponds to imx6_pcie_host_init(). > > > > Thanks for your kindly help to review it. That's reasonable. > > > > So, to make it symmetric with imx6_pcie_host_init() and > > imx6_pcie_start_link(). The according local functions > > imx6_pcie_host_exit() and imx6_pcie_stop_link() would be created. > > > > BTW, to be symmetric with imx6_pcie_host_init(), the parameter of > > imx6_pcie_host_exit() is same to the parameter of > > imx6_pcie_host_init(). So do imx6_pcie_stop_link() and > > imx6_pcie_start_link(). Are you satisfied with the following > > functions? > > > > static void imx6_pcie_stop_link(struct dw_pcie *pci) { > > struct device *dev = pci->dev; > > > > /* Turn off PCIe LTSSM */ > > imx6_pcie_ltssm_disable(dev); > > } > > > > static void imx6_pcie_host_exit(struct pcie_port *pp) { > > struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > > struct imx6_pcie *imx6_pcie = to_imx6_pcie(pci); > > > > imx6_pcie_clk_disable(imx6_pcie); > > if (imx6_pcie->phy) { > > if (phy_power_off(imx6_pcie->phy)) > > dev_err(pci->dev, "unable to power off PHY\n"); > > phy_exit(imx6_pcie->phy); > > } > > > > if (imx6_pcie->vpcie) > > regulator_disable(imx6_pcie->vpcie); > > } > > After the current series, imx6_pcie_host_init() looks like: > > imx6_pcie_host_init > phy_power_on > regulator_enable > imx6_pcie_deassert_core_reset > imx6_pcie_clk_enable > phy_init > > and you propose: > > imx6_pcie_host_exit > imx6_pcie_clk_disable > phy_power_off > phy_exit > regulator_disable > > Generally they should do things in the reverse order. > Hi Bjorn: Thanks a lot for your review. > imx6_pcie_host_init() does phy_power_on(), regulator_enable(), > imx6_pcie_clk_enable(). > > imx6_pcie_host_exit() should do imx6_pcie_clk_disable(), regulator_disable(), > phy_power_off(). > > (It looks like imx6_pcie_host_init() calls phy_power_on() and > phy_init() in the wrong order [1].) Yes, it is . I notice the warning too in my local tests. I made a mistake that I assumed the PHY should be powered on firstly, then be initialized. Since it is bug fix, how about to issue another fix commit after this series? > > IMO the imx6_pcie_clk_enable() should not be hidden inside > imx6_pcie_deassert_core_reset(). Okay, would move the imx6_pcie_clk_enable() from imx6_pcie_deassert_core_reset() to imx6_pcie_host_init(). Since the 6/15 of v13 has already Lucas' reviewed-by tag. Can I combine these changes with the creation of the imx6_pcie_host_exit() and imx6_pcie_host_stop_link() into one patch? > > [1] > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kern > el.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git%2Ftr > ee%2Fdrivers%2Fphy%2Fphy-core.c%3Fid%3Dv5.19-rc1%23n233&data= > 05%7C01%7Chongxing.zhu%40nxp.com%7C0e7ce8e53ee0478aabd508da591 > e06f7%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6379202827 > 66167735%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoi > V2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdat > a=BQQnn1ju47AGwfQW48%2Ba%2BnlLszha8P0QAynr4G3qeLM%3D&res > erved=0 Thanks a lot for your kindly reminder. Best Regards Richard
