From: Krishna Chaitanya Chundru <quic_krichai@quicinc.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: linux-pci@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-kernel@vger.kernel.org, mka@chromium.org,
quic_vbadigan@quicinc.com, quic_hemantk@quicinc.com,
quic_nitegupt@quicinc.com, quic_skananth@quicinc.com,
quic_ramkri@quicinc.com, manivannan.sadhasivam@linaro.org,
swboyd@chromium.org, dmitry.baryshkov@linaro.org,
"Stanimir Varbanov" <svarbanov@mm-sol.com>,
"Andy Gross" <agross@kernel.org>,
"Bjorn Andersson" <andersson@kernel.org>,
"Konrad Dybcio" <konrad.dybcio@somainline.org>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Rob Herring" <robh@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Bjorn Helgaas" <bhelgaas@google.com>
Subject: Re: [PATCH v6 2/5] PCI: qcom: Add retry logic for link to be stable in L1ss
Date: Mon, 12 Sep 2022 21:39:36 +0530 [thread overview]
Message-ID: <7310fc0c-5f87-87a6-4484-d60970ce3285@quicinc.com> (raw)
In-Reply-To: <20220909195000.GA310621@bhelgaas>
On 9/10/2022 1:20 AM, Bjorn Helgaas wrote:
> On Fri, Sep 09, 2022 at 02:14:41PM +0530, Krishna chaitanya chundru wrote:
>> Some specific devices are taking time to settle the link in L1ss.
>> So added a retry logic before returning from the suspend op.
> "L1ss" is not a state. If you mean "L1.1" or "L1.2", say that. Also
> in code comments below.
Yes L1ss means L1.2 and L1.2 We will update it next patch
> s/So added a/Add/
>
> What are these specific devices? Is this a qcom controller defect?
> An endpoint defect that should be addressed via some kind of generic
> quirk?
This is depending up on the endpoint devices and it varies to device to
device.
We are thinking this is not a defect if there is some traffic in the
link the link will
not go to L1ss .
>
>> Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
>> ---
>> drivers/pci/controller/dwc/pcie-qcom.c | 36 +++++++++++++++++++++++-----------
>> 1 file changed, 25 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
>> index 6e04d0d..15c2067 100644
>> --- a/drivers/pci/controller/dwc/pcie-qcom.c
>> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
>> @@ -1809,26 +1809,40 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>> static int __maybe_unused qcom_pcie_pm_suspend(struct qcom_pcie *pcie)
>> {
>> u32 val;
>> + ktime_t timeout, start;
>> struct dw_pcie *pci = pcie->pci;
>> struct device *dev = pci->dev;
>>
>> if (!pcie->cfg->supports_system_suspend)
>> return 0;
>>
>> - /* if the link is not active turn off clocks */
>> - if (!dw_pcie_link_up(pci)) {
>> - dev_info(dev, "Link is not active\n");
>> - goto suspend;
>> - }
>> + start = ktime_get();
>> + /* Wait max 200 ms */
>> + timeout = ktime_add_ms(start, 200);
>>
>> - /* if the link is not in l1ss don't turn off clocks */
>> - val = readl(pcie->parf + PCIE20_PARF_PM_STTS);
>> - if (!(val & PCIE20_PARF_PM_STTS_LINKST_IN_L1SUB)) {
>> - dev_warn(dev, "Link is not in L1ss\n");
>> - return 0;
>> + while (1) {
>> +
>> + if (!dw_pcie_link_up(pci)) {
>> + dev_warn(dev, "Link is not active\n");
>> + break;
>> + }
>> +
>> + /* if the link is not in l1ss don't turn off clocks */
>> + val = readl(pcie->parf + PCIE20_PARF_PM_STTS);
>> + if ((val & PCIE20_PARF_PM_STTS_LINKST_IN_L1SUB)) {
>> + dev_dbg(dev, "Link enters L1ss after %d ms\n",
>> + ktime_to_ms(ktime_get() - start));
>> + break;
>> + }
>> +
>> + if (ktime_after(ktime_get(), timeout)) {
>> + dev_warn(dev, "Link is not in L1ss\n");
>> + return 0;
>> + }
>> +
>> + udelay(1000);
>> }
>>
>> -suspend:
>> if (pcie->cfg->ops->suspend)
>> pcie->cfg->ops->suspend(pcie);
>>
>> --
>> 2.7.4
>>
next prev parent reply other threads:[~2022-09-12 16:15 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-09 8:44 [PATCH v6 0/5] PCI: qcom: Add system suspend & resume support Krishna chaitanya chundru
2022-09-09 8:44 ` [PATCH v6 1/5] PCI: qcom: Add system suspend and " Krishna chaitanya chundru
2022-09-09 17:31 ` Matthias Kaehlcke
2022-09-12 16:06 ` Krishna Chaitanya Chundru
2022-09-12 16:54 ` Matthias Kaehlcke
2022-09-12 17:09 ` Manivannan Sadhasivam
2022-09-09 8:44 ` [PATCH v6 2/5] PCI: qcom: Add retry logic for link to be stable in L1ss Krishna chaitanya chundru
2022-09-09 19:50 ` Bjorn Helgaas
2022-09-12 16:09 ` Krishna Chaitanya Chundru [this message]
2022-09-12 17:33 ` Manivannan Sadhasivam
2022-09-13 14:24 ` Krishna Chaitanya Chundru
2022-09-13 16:39 ` Manivannan Sadhasivam
2022-09-14 1:45 ` Krishna Chaitanya Chundru
2022-09-14 5:59 ` Manivannan Sadhasivam
2022-09-19 16:23 ` kernel test robot
2022-09-09 8:44 ` [PATCH v6 3/5] phy: core: Add support for phy power down & power up Krishna chaitanya chundru
2022-09-09 9:04 ` Dmitry Baryshkov
2022-09-14 14:50 ` Krishna Chaitanya Chundru
2022-09-19 17:29 ` Dmitry Baryshkov
2022-09-20 9:41 ` Krishna Chaitanya Chundru
2022-09-13 14:58 ` Vinod Koul
2022-09-13 16:41 ` Bjorn Helgaas
2022-09-09 8:44 ` [PATCH v6 4/5] phy: qcom: Add power down/up callbacks to pcie phy Krishna chaitanya chundru
2022-09-09 8:44 ` [PATCH v6 5/5] clk: qcom: Alwaya on pcie gdsc Krishna chaitanya chundru
2022-09-12 17:04 ` Manivannan Sadhasivam
2022-09-13 6:42 ` Rajendra Nayak
2022-09-13 16:42 ` Manivannan Sadhasivam
2022-09-14 1:47 ` Krishna Chaitanya Chundru
2022-09-13 16:34 ` Bjorn Helgaas
2022-09-14 1:48 ` Krishna Chaitanya Chundru
2022-09-09 19:51 ` [PATCH v6 0/5] PCI: qcom: Add system suspend & resume support Bjorn Helgaas
2022-09-12 16:10 ` Krishna Chaitanya Chundru
2022-09-12 17:08 ` Bjorn Helgaas
2022-09-12 17:21 ` Manivannan Sadhasivam
2022-09-12 17:37 ` Manivannan Sadhasivam
2022-09-14 1:47 ` Krishna Chaitanya Chundru
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