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SubjectRe: [PATCH v1 3/3] PCI: qcom: Add OPP suuport for speed based performance state of RPMH
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On 8/16/2023 11:54 AM, Pavan Kondeti wrote:
> On Tue, Aug 15, 2023 at 05:56:48PM +0530, Krishna chaitanya chundru wrote:
>> Before link training vote for the maximum performance state of RPMH
>> and once the link is up, vote for the performance state based upon
>> the link speed.
>> Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
>> ---
>> drivers/pci/controller/dwc/pcie-qcom.c | 61 ++++++++++++++++++++++++++++++++++
>> 1 file changed, 61 insertions(+)
>>
>> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
>> index 7a87a47..e29a986 100644
>> --- a/drivers/pci/controller/dwc/pcie-qcom.c
>> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
>> @@ -22,6 +22,7 @@
>> #include <linux/of_device.h>
>> #include <linux/of_gpio.h>
>> #include <linux/pci.h>
>> +#include <linux/pm_opp.h>
>> #include <linux/pm_runtime.h>
>> #include <linux/platform_device.h>
>> #include <linux/phy/pcie.h>
>> @@ -1357,6 +1358,51 @@ static int qcom_pcie_icc_init(struct qcom_pcie *pcie)
>> return 0;
>> }
>>
>> +static void qcom_pcie_opp_update(struct qcom_pcie *pcie)
>> +{
>> + struct dw_pcie *pci = pcie->pci;
>> + struct dev_pm_opp *opp;
>> + u32 offset, status;
>> + uint32_t freq;
>> + int speed;
>> + int ret = 0;
>> +
>> + offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
>> + status = readw(pci->dbi_base + offset + PCI_EXP_LNKSTA);
>> +
>> + /* Only update constraints if link is up. */
>> + if (!(status & PCI_EXP_LNKSTA_DLLLA))
>> + return;
>> +
>> + speed = FIELD_GET(PCI_EXP_LNKSTA_CLS, status);
>> +
>> + switch (speed) {
>> + case 1:
>> + freq = 2500000;
>> + break;
>> + case 2:
>> + freq = 5000000;
>> + break;
>> + case 3:
>> + freq = 8000000;
>> + break;
>> + default:
>> + WARN_ON_ONCE(1);
>> + fallthrough;
>> + case 4:
>> + freq = 16000000;
>> + break;
>> + }
>> +
>> + opp = dev_pm_opp_find_freq_exact(pci->dev, freq, true);
>> +
>> + if (!IS_ERR(opp)) {
>> + ret = dev_pm_opp_get_voltage(opp);
>> + dev_pm_opp_put(opp);
>> + }
>> +
> Where are we setting the OPP here?
>
>> +}
>> +
>> static void qcom_pcie_icc_update(struct qcom_pcie *pcie)
>> {
>> struct dw_pcie *pci = pcie->pci;
>> @@ -1439,8 +1485,10 @@ static void qcom_pcie_init_debugfs(struct qcom_pcie *pcie)
>> static int qcom_pcie_probe(struct platform_device *pdev)
>> {
>> const struct qcom_pcie_cfg *pcie_cfg;
>> + unsigned long max_freq = INT_MAX;
>> struct device *dev = &pdev->dev;
>> struct qcom_pcie *pcie;
>> + struct dev_pm_opp *opp;
>> struct dw_pcie_rp *pp;
>> struct resource *res;
>> struct dw_pcie *pci;
>> @@ -1511,6 +1559,17 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>> if (ret)
>> goto err_pm_runtime_put;
>>
>> + /* OPP table is optional */
>> + ret = devm_pm_opp_of_add_table(dev);
>> + if (ret && ret != -ENODEV) {
>> + dev_err(dev, "Invalid OPP table in Device tree\n");
>> + goto err_pm_runtime_put;
>> + }
>> +
>> + opp = dev_pm_opp_find_freq_floor(dev, &max_freq);
>> + if (!IS_ERR(opp))
>> + dev_pm_opp_put(opp);
>> +
> This OPP (corresponding to max freq) is not used, so how are we voting
> for max perf state during probe?
>
>> ret = pcie->cfg->ops->get_resources(pcie);
>> if (ret)
>> goto err_pm_runtime_put;
>> @@ -1531,6 +1590,8 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>>
>> qcom_pcie_icc_update(pcie);
>>
>> + qcom_pcie_opp_update(pcie);
>> +
> commit description says, OPP voting is done as per the link speed after
> probe? I don't see any calls to qcom_pcie_opp_update() outside probe.

my mistake dev_pm_opp_set_opp somehow missed here I will update in next
patch.

- KC

>> if (pcie->mhi)
>> qcom_pcie_init_debugfs(pcie);
>>
>>
> Thanks,
> Pavan

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