On Sun, Apr 07, 2024 at 10:07:39AM +0530, Krishna chaitanya chundru wrote:
> QCOM Resource Power Manager-hardened (RPMh) is a hardware block which
> maintains hardware state of a regulator by performing max aggregation of
> the requests made by all of the clients.
>
> PCIe controller can operate on different RPMh performance state of power
> domain based on the speed of the link. And this performance state varies
> from target to target, like some controllers support GEN3 in NOM (Nominal)
> voltage corner, while some other supports GEN3 in low SVS (static voltage
> scaling).
>
> The SoC can be more power efficient if we scale the performance state
> based on the aggregate PCIe link bandwidth.
>
> Add Operating Performance Points (OPP) support to vote for RPMh state based
> on the aggregate link bandwidth.
>
> OPP can handle ICC bw voting also, so move ICC bw voting through OPP
> framework if OPP entries are present.
>
> Different link configurations may share the same aggregate bandwidth,
> e.g., a 2.5 GT/s x2 link and a 5.0 GT/s x1 link have the same bandwidth
> and share the same OPP entry.
>
This info should be part of the dts change.
> As we are moving ICC voting as part of OPP, don't initialize ICC if OPP
> is supported.
>
> Before PCIe link is initialized vote for highest OPP in the OPP table,
> so that we are voting for maximum voltage corner for the link to come up
> in maximum supported speed.
>
> Signed-off-by: Krishna chaitanya chundru <quic_krichai@xxxxxxxxxxx>
> ---
> drivers/pci/controller/dwc/pcie-qcom.c | 72 +++++++++++++++++++++++++++-------
> 1 file changed, 58 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index b4893214b2d3..4ad5ef3bf8fc 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -22,6 +22,7 @@
> #include <linux/of.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>
> @@ -1442,15 +1443,13 @@ static int qcom_pcie_icc_init(struct qcom_pcie *pcie)
> return 0;
> }
>
> -static void qcom_pcie_icc_update(struct qcom_pcie *pcie)
> +static void qcom_pcie_icc_opp_update(struct qcom_pcie *pcie)
> {
> struct dw_pcie *pci = pcie->pci;
> - u32 offset, status;
> + u32 offset, status, freq;
> + struct dev_pm_opp *opp;
> int speed, width;
> - int ret;
> -
> - if (!pcie->icc_mem)
> - return;
> + int ret, mbps;
>
> offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
> status = readw(pci->dbi_base + offset + PCI_EXP_LNKSTA);
> @@ -1462,10 +1461,26 @@ static void qcom_pcie_icc_update(struct qcom_pcie *pcie)
> speed = FIELD_GET(PCI_EXP_LNKSTA_CLS, status);
> width = FIELD_GET(PCI_EXP_LNKSTA_NLW, status);
>
> - ret = icc_set_bw(pcie->icc_mem, 0, width * QCOM_PCIE_LINK_SPEED_TO_BW(speed));
> - if (ret) {
> - dev_err(pci->dev, "failed to set interconnect bandwidth for PCIe-MEM: %d\n",
> - ret);
> + if (pcie->icc_mem) {
> + ret = icc_set_bw(pcie->icc_mem, 0, width * QCOM_PCIE_LINK_SPEED_TO_BW(speed));
> + if (ret) {
> + dev_err(pci->dev, "failed to set interconnect bandwidth for PCIe-MEM: %d\n",
s/failed/Failed
> + ret);
> + }
> + } else {
> + mbps = pcie_link_speed_to_mbps(pcie_link_speed[speed]);
> + if (mbps < 0)
> + return;
> +
> + freq = mbps * 1000;
> + opp = dev_pm_opp_find_freq_exact(pci->dev, freq * width, true);
As per the API documentation, dev_pm_opp_put() should be called for both success
and failure case.
> + if (!IS_ERR(opp)) {
So what is the action if OPP is not found for the freq?
> + ret = dev_pm_opp_set_opp(pci->dev, opp);
> + if (ret)
> + dev_err(pci->dev, "Failed to set opp: freq %ld ret %d\n",
'Failed to set OPP for freq (%ld): %d'
> + dev_pm_opp_get_freq(opp), ret);
> + dev_pm_opp_put(opp);
> + }
> }
> }
>
> @@ -1509,8 +1524,10 @@ 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;
> @@ -1577,9 +1594,33 @@ static int qcom_pcie_probe(struct platform_device *pdev)
> goto err_pm_runtime_put;
> }
>
> - ret = qcom_pcie_icc_init(pcie);
> - if (ret)
> + /* OPP table is optional */
> + ret = devm_pm_opp_of_add_table(dev);
> + if (ret && ret != -ENODEV) {
> + dev_err_probe(dev, ret, "Failed to add OPP table\n");
> goto err_pm_runtime_put;
> + }
> +
> + /*
> + * Use highest OPP here if the OPP table is present. At the end of
I believe I asked you to add the information justifying why the highest OPP
should be used.
> + * the probe(), OPP will be updated using qcom_pcie_icc_opp_update().
> + */
> + if (!ret) {
> + opp = dev_pm_opp_find_freq_floor(dev, &max_freq);
Same comment as dev_pm_opp_find_freq_exact().
> + if (!IS_ERR(opp)) {
> + ret = dev_pm_opp_set_opp(dev, opp);
> + if (ret)
> + dev_err_probe(pci->dev, ret,
> + "Failed to set OPP: freq %ld\n",
Same comment as above.
> + dev_pm_opp_get_freq(opp));
> + dev_pm_opp_put(opp);
So you want to continue even in the case of failure?
- Mani
> + }
> + } else {
> + /* Skip ICC init if OPP is supported as it is handled by OPP */
> + ret = qcom_pcie_icc_init(pcie);
> + if (ret)
> + goto err_pm_runtime_put;
> + }
>
> ret = pcie->cfg->ops->get_resources(pcie);
> if (ret)
> @@ -1599,7 +1640,7 @@ static int qcom_pcie_probe(struct platform_device *pdev)
> goto err_phy_exit;
> }
>
> - qcom_pcie_icc_update(pcie);
> + qcom_pcie_icc_opp_update(pcie);
>
> if (pcie->mhi)
> qcom_pcie_init_debugfs(pcie);
> @@ -1658,6 +1699,9 @@ static int qcom_pcie_suspend_noirq(struct device *dev)
> if (ret)
> dev_err(dev, "failed to disable icc path of CPU-PCIe: %d\n", ret);
>
> + if (!pcie->icc_mem)
> + dev_pm_opp_set_opp(pcie->pci->dev, NULL);
> +
> return ret;
> }
>
> @@ -1680,7 +1724,7 @@ static int qcom_pcie_resume_noirq(struct device *dev)
> pcie->suspended = false;
> }
>
> - qcom_pcie_icc_update(pcie);
> + qcom_pcie_icc_opp_update(pcie);
>
> return 0;
> }
>
> --
> 2.42.0
>
--
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