From: Hongxing Zhu <hongxing.zhu@nxp.com>
To: Lucas Stach <l.stach@pengutronix.de>,
"bhelgaas@google.com" <bhelgaas@google.com>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"broonie@kernel.org" <broonie@kernel.org>,
"lorenzo.pieralisi@arm.com" <lorenzo.pieralisi@arm.com>,
"festevam@gmail.com" <festevam@gmail.com>,
"francesco.dolcini@toradex.com" <francesco.dolcini@toradex.com>
Cc: "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kernel@pengutronix.de" <kernel@pengutronix.de>,
dl-linux-imx <linux-imx@nxp.com>
Subject: RE: [PATCH v14 14/17] PCI: imx6: Do not hide phy driver callbacks and refine the error handling
Date: Wed, 13 Jul 2022 12:52:31 +0000 [thread overview]
Message-ID: <AS8PR04MB8676BC6BE5415AD37EF833A08C899@AS8PR04MB8676.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <5bb33ccf17f89cd398342922af6fd7a04f015c07.camel@pengutronix.de>
> -----Original Message-----
> From: Lucas Stach <l.stach@pengutronix.de>
> Sent: 2022年7月13日 19:17
> To: Hongxing Zhu <hongxing.zhu@nxp.com>; bhelgaas@google.com;
> robh+dt@kernel.org; broonie@kernel.org; lorenzo.pieralisi@arm.com;
> festevam@gmail.com; francesco.dolcini@toradex.com
> Cc: linux-pci@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
> linux-kernel@vger.kernel.org; kernel@pengutronix.de; dl-linux-imx
> <linux-imx@nxp.com>
> Subject: Re: [PATCH v14 14/17] PCI: imx6: Do not hide phy driver callbacks and
> refine the error handling
>
> Am Mittwoch, dem 13.07.2022 um 10:57 +0000 schrieb Hongxing Zhu:
> > > -----Original Message-----
> > > From: Lucas Stach <l.stach@pengutronix.de>
> > > Sent: 2022年7月13日 16:59
> > > To: Hongxing Zhu <hongxing.zhu@nxp.com>; bhelgaas@google.com;
> > > robh+dt@kernel.org; broonie@kernel.org; lorenzo.pieralisi@arm.com;
> > > festevam@gmail.com; francesco.dolcini@toradex.com
> > > Cc: linux-pci@vger.kernel.org;
> > > linux-arm-kernel@lists.infradead.org;
> > > linux-kernel@vger.kernel.org; kernel@pengutronix.de; dl-linux-imx
> > > <linux-imx@nxp.com>
> > > Subject: Re: [PATCH v14 14/17] PCI: imx6: Do not hide phy driver
> > > callbacks and refine the error handling
> > >
> > > Am Freitag, dem 01.07.2022 um 11:25 +0800 schrieb Richard Zhu:
> > > > - Move the phy_power_on() to host_init from
> > > > imx6_pcie_clk_enable().
> > > > - Move the phy_init() to host_init from
> > > > imx6_pcie_deassert_core_reset().
> > > >
> > > > Refine the error handling in imx6_pcie_host_init() accordingly.
> > > >
> > > > Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> > > > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> > > > ---
> > > > drivers/pci/controller/dwc/pci-imx6.c | 34 +++++++++++++++++----
> > > > ------
> > > > 1 file changed, 21 insertions(+), 13 deletions(-)
> > > >
> > > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > > b/drivers/pci/controller/dwc/pci-imx6.c
> > > > index 5a06fbca82d6..0b2a5256fb0d 100644
> > > > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > > > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > > > @@ -639,14 +639,6 @@ static int imx6_pcie_clk_enable(struct
> > > > imx6_pcie
> > > *imx6_pcie)
> > > > goto err_ref_clk;
> > > > }
> > > >
> > > > - switch (imx6_pcie->drvdata->variant) {
> > > > - case IMX8MM:
> > > > - if (phy_power_on(imx6_pcie->phy))
> > > > - dev_err(dev, "unable to power on
> > > > PHY\n");
> > > > - break;
> > > > - default:
> > > > - break;
> > > > - }
> > > > /* allow the clocks to stabilize */
> > > > usleep_range(200, 500);
> > > > return 0;
> > > > @@ -723,10 +715,6 @@ static int
> > > > imx6_pcie_deassert_core_reset(struct
> > > imx6_pcie *imx6_pcie)
> > > > case IMX8MQ:
> > > > reset_control_deassert(imx6_pcie-
> > > > >pciephy_reset);
> > > > break;
> > > > - case IMX8MM:
> > > > - if (phy_init(imx6_pcie->phy))
> > > > - dev_err(dev, "waiting for phy ready
> > > > timeout!\n");
> > > > - break;
> > > > case IMX7D:
> > > > reset_control_deassert(imx6_pcie-
> > > > >pciephy_reset);
> > > >
> > > > @@ -762,6 +750,7 @@ static int
> > > > imx6_pcie_deassert_core_reset(struct
> > > imx6_pcie *imx6_pcie)
> > > > usleep_range(200, 500);
> > > > break;
> > > > case IMX6Q: /* Nothing to do */
> > > > + case IMX8MM:
> > > > break;
> > > > }
> > > >
> > > > @@ -913,17 +902,36 @@ static int imx6_pcie_host_init(struct
> > > > pcie_port
> > > *pp)
> > > > return ret;
> > > > }
> > > > }
> > > > + if (imx6_pcie->phy) {
> > > > + ret = phy_power_on(imx6_pcie->phy);
> > > > + if (ret) {
> > > > + dev_err(dev, "pcie phy power up
> > > > failed.\n");
> > > > + goto err_reg_disable;
> > > > + }
> > > > + }
> > > >
> > > > ret = imx6_pcie_deassert_core_reset(imx6_pcie);
> > > > if (ret < 0) {
> > > > dev_err(dev, "pcie deassert core reset failed:
> > > > %d\n", ret);
> > > > - goto err_reg_disable;
> > > > + goto err_phy_off;
> > > > }
> > > >
> > > > + if (imx6_pcie->phy) {
> > > > + ret = phy_init(imx6_pcie->phy);
> > > > + if (ret) {
> > > > + dev_err(dev, "waiting for phy ready
> > > > timeout!\n");
> > > > + goto err_clk_disable;
> > > > + }
> > > > + }
> > >
> > > Wouldn't it be more logical to put this into imx6_pcie_init_phy()?
> > >
> > Before adding i.MX8MM PCIe support, the imx6_pcie_init_phy() only
> > touches the
> > GPR registers. PCIe clocks and so on are not required in this case.
> > But phy_init() used by i.MX8MM PCIe touches not only the GPR registers
> > but
> > also the PHY's registers.
> > The clocks should be on and resets of PHY should be configured
> > properly when
> > phy_init() is invoked.
> > So, phy_init() is placed behind of imx6_pcie_deassert_core_reset()
> > here.
>
> The PHY driver should be self-contained enough to not care about the state of
> the controller here, no? It should set all the necessary GPRs and enable clocks
> as needed on its own. Is this not the case with the current code?
>
> Also PHY init should be called before PHY power-on, to make things symmetric
> with the shutdown paths which do phy_power_off() first, then phy_exit().
>
Thanks for your comments.
Yes, agree with that PHY driver should be self-contained enough.
I mis-understood the sequence of phy_init() and phy_power_on() when I add
the PHY driver. The phy_init() is relied on the phy_power_on() here.
So, I have to place the phy_init() behind phy_power_on() currently.
I think the phy_init() can be placed in imx6_pcie_init_phy() when the order
issue is fixed.
BTW, Bjorn had noticed me this issue too [1]. Since it's a bug, I would issue
another standalone bug fix commits to resolve this issue later.
[1] https://patchwork.ozlabs.org/project/linux-pci/patch/1655461874-16908-11-git-send-email-hongxing.zhu@nxp.com/
Best Regards
Richard Zhu
> Regards,
> Lucas
next prev parent reply other threads:[~2022-07-13 12:52 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-01 3:25 [PATCH v14 0/17] PCI: imx6: refine codes and add the error propagation Richard Zhu
2022-07-01 3:25 ` [PATCH v14 01/17] PCI: imx6: Move imx6_pcie_grp_offset(), imx6_pcie_configure_type() earlier Richard Zhu
2022-07-13 8:13 ` Lucas Stach
2022-07-01 3:25 ` [PATCH v14 02/17] PCI: imx6: Move PHY management functions together Richard Zhu
2022-07-13 8:15 ` Lucas Stach
2022-07-01 3:25 ` [PATCH v14 03/17] PCI: imx6: Move imx6_pcie_enable_ref_clk() earlier Richard Zhu
2022-07-13 8:16 ` Lucas Stach
2022-07-01 3:25 ` [PATCH v14 04/17] PCI: imx6: Move imx6_pcie_clk_disable() earlier Richard Zhu
2022-07-01 3:25 ` [PATCH v14 05/17] PCI: imx6: Factor out ref clock disable to match enable Richard Zhu
2022-07-13 8:17 ` Lucas Stach
2022-07-01 3:25 ` [PATCH v14 06/17] PCI: imx6: Collect clock enables in imx6_pcie_clk_enable() Richard Zhu
2022-07-01 3:25 ` [PATCH v14 07/17] PCI: imx6: Propagate .host_init() errors to caller Richard Zhu
2022-07-01 3:25 ` [PATCH v14 08/17] PCI: imx6: Disable i.MX6QDL clock when disabling ref clocks Richard Zhu
2022-07-01 3:25 ` [PATCH v14 09/17] PCI: imx6: Call host init function directly in resume Richard Zhu
2022-07-13 8:26 ` Lucas Stach
2022-07-01 3:25 ` [PATCH v14 10/17] PCI: imx6: Turn off regulator when system is in suspend mode Richard Zhu
2022-07-13 8:34 ` Lucas Stach
2022-07-13 10:56 ` Hongxing Zhu
2022-07-13 11:22 ` Lucas Stach
2022-07-13 12:55 ` Hongxing Zhu
2022-07-01 3:25 ` [PATCH v14 11/17] PCI: imx6: Move regulator enable out of imx6_pcie_deassert_core_reset() Richard Zhu
2022-07-13 8:41 ` Lucas Stach
2022-07-13 10:57 ` Hongxing Zhu
2022-07-01 3:25 ` [PATCH v14 12/17] PCI: imx6: Mark the link down as non-fatal error Richard Zhu
2022-07-13 8:44 ` Lucas Stach
2022-07-01 3:25 ` [PATCH v14 13/17] PCI: imx6: Reduce resume time by only starting link if it was up before suspend Richard Zhu
2022-07-13 8:47 ` Lucas Stach
2022-07-13 10:57 ` Hongxing Zhu
2022-07-01 3:25 ` [PATCH v14 14/17] PCI: imx6: Do not hide phy driver callbacks and refine the error handling Richard Zhu
2022-07-13 8:58 ` Lucas Stach
2022-07-13 10:57 ` Hongxing Zhu
2022-07-13 11:17 ` Lucas Stach
2022-07-13 12:52 ` Hongxing Zhu [this message]
2022-07-01 3:25 ` [PATCH v14 15/17] PCI: imx6: Disable clocks in reverse order of enable Richard Zhu
2022-07-13 8:59 ` Lucas Stach
2022-07-01 3:25 ` [PATCH v14 16/17] PCI: imx6: Move the imx6_pcie_ltssm_disable() earlier Richard Zhu
2022-07-13 9:04 ` Lucas Stach
2022-07-13 11:00 ` Hongxing Zhu
2022-07-01 3:25 ` [PATCH v14 17/17] PCI: imx6: Reformat suspend callback to keep symmetric with resume Richard Zhu
2022-07-13 9:07 ` Lucas Stach
2022-07-11 22:29 ` [PATCH v14 0/17] PCI: imx6: refine codes and add the error propagation Bjorn Helgaas
2022-07-13 16:45 ` Bjorn Helgaas
2022-07-14 4:15 ` Hongxing Zhu
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