[PATCH v5 5/5] PCI: qcom: Add OPP support to scale performance state of power domain

[Krishna chaitanya chundru <quic_krichai@quicinc.com>]

While scaling the interconnect clocks based on PCIe link speed, it is also
mandatory to scale the power domain performance state so that the SoC can
run under optimum power conditions.

Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
---
 drivers/pci/controller/dwc/pcie-qcom.c | 58 ++++++++++++++++++++++++++++------
 1 file changed, 49 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index ca6350b..1817e96 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>
@@ -240,6 +241,7 @@ struct qcom_pcie {
 	const struct qcom_pcie_cfg *cfg;
 	struct dentry *debugfs;
 	bool suspended;
+	bool opp_supported;
 };
 
 #define to_qcom_pcie(x)		dev_get_drvdata((x)->dev)
@@ -1357,14 +1359,13 @@ static int qcom_pcie_icc_init(struct qcom_pcie *pcie)
 	return 0;
 }
 
-static int qcom_pcie_icc_update(struct qcom_pcie *pcie)
+static int qcom_pcie_icc_opp_update(struct qcom_pcie *pcie)
 {
 	struct dw_pcie *pci = pcie->pci;
+	struct dev_pm_opp *opp;
 	u32 offset, status, bw;
 	int speed, width;
-
-	if (!pcie->icc_mem)
-		return 0;
+	int ret;
 
 	offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
 	status = readw(pci->dbi_base + offset + PCI_EXP_LNKSTA);
@@ -1391,7 +1392,21 @@ static int qcom_pcie_icc_update(struct qcom_pcie *pcie)
 		break;
 	}
 
-	return icc_set_bw(pcie->icc_mem, 0, width * bw);
+	if (pcie->opp_supported) {
+		opp = dev_pm_opp_find_level_exact(pci->dev, speed);
+		if (!IS_ERR(opp)) {
+			ret = dev_pm_opp_set_opp(pci->dev, opp);
+			if (ret)
+				dev_err(pci->dev, "Failed to set opp: level %d ret %d\n",
+					dev_pm_opp_get_level(opp), ret);
+			dev_pm_opp_put(opp);
+		}
+	}
+
+	if (pcie->icc_mem)
+		ret = icc_set_bw(pcie->icc_mem, 0, width * bw);
+
+	return ret;
 }
 
 static int qcom_pcie_link_transition_count(struct seq_file *s, void *data)
@@ -1434,8 +1449,10 @@ 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_level = 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;
@@ -1506,6 +1523,27 @@ 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_probe(dev, ret, "Failed to add OPP table\n");
+		goto err_pm_runtime_put;
+	}
+
+	/* vote for max level in the opp table if opp table is present */
+	if (ret != -ENODEV) {
+		opp = dev_pm_opp_find_level_floor(dev, &max_level);
+		if (!IS_ERR(opp)) {
+			ret = dev_pm_opp_set_opp(dev, opp);
+			if (ret)
+				dev_err_probe(pci->dev, ret,
+					      "Failed to set opp: level %d\n",
+					      dev_pm_opp_get_level(opp));
+			dev_pm_opp_put(opp);
+		}
+		pcie->opp_supported = true;
+	}
+
 	ret = pcie->cfg->ops->get_resources(pcie);
 	if (ret)
 		goto err_pm_runtime_put;
@@ -1524,9 +1562,9 @@ static int qcom_pcie_probe(struct platform_device *pdev)
 		goto err_phy_exit;
 	}
 
-	ret = qcom_pcie_icc_update(pcie);
+	ret = qcom_pcie_icc_opp_update(pcie);
 	if (ret)
-		dev_err(dev, "failed to update interconnect bandwidth: %d\n",
+		dev_err(dev, "failed to update interconnect bandwidth/opp: %d\n",
 			ret);
 
 	if (pcie->mhi)
@@ -1575,6 +1613,8 @@ static int qcom_pcie_suspend_noirq(struct device *dev)
 	 */
 	if (!dw_pcie_link_up(pcie->pci)) {
 		qcom_pcie_host_deinit(&pcie->pci->pp);
+		if (pcie->opp_supported)
+			dev_pm_opp_set_opp(dev, NULL);
 		pcie->suspended = true;
 	}
 
@@ -1594,9 +1634,9 @@ static int qcom_pcie_resume_noirq(struct device *dev)
 		pcie->suspended = false;
 	}
 
-	ret = qcom_pcie_icc_update(pcie);
+	ret = qcom_pcie_icc_opp_update(pcie);
 	if (ret)
-		dev_err(dev, "failed to update interconnect bandwidth: %d\n",
+		dev_err(dev, "failed to update interconnect bandwidth/opp: %d\n",
 			ret);
 
 	return 0;
-- 
2.7.4