Re: [PATCH v2] PCI: qcom: Add system PM support

[Prasad Malisetty]

Hi Mani,

Thanks for the review and comments.

I updated my mail client. sending the same responses. I will post the 
new patch version.

Testing is in progress.

Thanks

-Prasad

On 2/11/2022 2:44 PM, Manivannan Sadhasivam wrote:
> On top of Bjorn's review:
>
> On Tue, Feb 01, 2022 at 11:37:56PM +0530, Prasad Malisetty wrote:
> > Add suspend_noirq and resume_noirq callbacks to handle
> > System suspend and resume in dwc pcie controller driver.
> >
> > When system suspends, send PME turnoff message to enter
> > link into L2 state. Along with powerdown the PHY, disable
> > pipe clock, switch gcc_pcie_1_pipe_clk_src to XO if mux is
> > supported and disable the pcie clocks, regulators.
> >
> > When system resumes, PCIe link will be re-established and
> > setup rc settings.
> >
> > Signed-off-by: Prasad Malisetty <quic_pmaliset@xxxxxxxxxxx>
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> >
> > ---
> > Changes since v1:
> > 	- Removed unnecessary logs and modified log level suggested by Manivannan.
> > 	- Removed platform specific callbacks as PM support is generic.
> This is not still generic... Please see below.
>
> > ---
> >   drivers/pci/controller/dwc/pcie-qcom.c | 97 ++++++++++++++++++++++++++++++++++
> >   1 file changed, 97 insertions(+)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> > index c19cd506..d1dd6c7 100644
> > --- a/drivers/pci/controller/dwc/pcie-qcom.c
> > +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> > @@ -73,6 +73,8 @@
> >   
> >   #define PCIE20_PARF_Q2A_FLUSH			0x1AC
> >   
> > +#define PCIE20_PARF_PM_STTS                     0x24
> > +
> >   #define PCIE20_MISC_CONTROL_1_REG		0x8BC
> >   #define DBI_RO_WR_EN				1
> >   
> > @@ -1616,6 +1618,100 @@ static int qcom_pcie_probe(struct platform_device *pdev)
> >   	return ret;
> >   }
> >   
> > +static int qcom_pcie_send_pme_turnoff_msg(struct qcom_pcie *pcie)
> > +{
> > +	int ret = 0;
> > +	u32 val = 0, poll_val = 0;
> > +	u64 l23_rdy_poll_timeout = 100000;
> > +	struct dw_pcie *pci = pcie->pci;
> > +	struct device *dev = pci->dev;
> > +
> > +	val = readl(pcie->elbi + PCIE20_ELBI_SYS_CTRL);
> > +	val |= BIT(4);
> Define BIT(4)
Sure, I will update in next patch version.
> > +	writel(val, pcie->elbi + PCIE20_ELBI_SYS_CTRL);
> > +
> > +	ret = readl_poll_timeout((pcie->parf + PCIE20_PARF_PM_STTS), poll_val,
> > +			(poll_val & BIT(5)), 10000, l23_rdy_poll_timeout);
> Define BIT(5)
Sure, I will update in next patch version.
> > +	if (!ret)
> > +		dev_info(dev, "PM_Enter_L23 is received\n");
> Maybe print, "Device entered L23_Ready state"? Also this should be dev_dbg().
>
> > +	else
> > +		dev_err(dev, "PM_Enter_L23 is NOT received.PARF_PM_STTS 0x%x\n",
> Maybe print, "Device failed to enter L23_Ready state"?
Agree, I will update in next patch version.
> > +			readl_relaxed(pcie->parf + PCIE20_PARF_PM_STTS));
> > +
> > +	return ret;
> > +}
> > +
> > +static void qcom_pcie_host_disable(struct qcom_pcie *pcie)
> > +{
> > +	struct qcom_pcie_resources_2_7_0 *res = &pcie->res.v2_7_0;
> > +
> As Bjorn said this would only work for platforms supporting v2.7.0 ops. Please
> make it generic.
I removed platform specific code but forgot to remove above one. will 
update in next patch version.
> > +	/* Assert the reset of endpoint */
> > +	qcom_ep_reset_assert(pcie);
> > +
> > +	/* Put PHY into POWER DOWN state */
> > +	phy_power_off(pcie->phy);
> > +
> > +	writel(1, pcie->parf + PCIE20_PARF_PHY_CTRL);
> Define "1".
Sure, I will update in next patch version.
> Thanks,
> Mani