Hi Richard,
On Tue, Feb 8, 2022 at 12:57 AM Richard Zhu <[email protected]> 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.
Please check:
https://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/pci.git/commit/?h=pci/imx6&id=f81f095e87715e198471f4653952fe5e3f824874
and
https://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/pci.git/commit/?h=pci/imx6&id=886a9c134755
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 <[email protected]>
> ---
> 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
>
> -----Original Message-----
> From: Fabio Estevam <[email protected]>
> Sent: 2022??2??8?? 18:10
> To: Hongxing Zhu <[email protected]>
> Cc: Lucas Stach <[email protected]>; Bjorn Helgaas
> <[email protected]>; Mark Brown <[email protected]>; Lorenzo Pieralisi
> <[email protected]>; Jingoo Han <[email protected]>;
> [email protected]; dl-linux-imx <[email protected]>; moderated
> list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE
> <[email protected]>; linux-kernel
> <[email protected]>; Sascha Hauer <[email protected]>
> 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 <[email protected]>
> 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 <[email protected]>
> > ---
> > 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
> >