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

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Date:   Thu, 17 Feb 2022 15:53:13 +0530
From:   Prasad Malisetty <quic_pmaliset@...cinc.com>
To:     Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
CC:     <agross@...nel.org>, <bjorn.andersson@...aro.org>,
        <lorenzo.pieralisi@....com>, <robh@...nel.org>, <kw@...ux.com>,
        <bhelgaas@...gle.com>, <linux-pci@...r.kernel.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <quic_vbadigan@...cinc.com>, <quic_ramkri@...cinc.com>,
        <swboyd@...omium.org>
Subject: Re: [PATCH v2] PCI: qcom: Add system PM support

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@...cinc.com>
>> Reported-by: kernel test robot <lkp@...el.com>
>>
>> ---
>> 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