[PATCH 2/3] usb: dwc3: qcom: Add interconnect support in dwc3 driver

[Chandana Kishori Chiluveru <cchiluve@codeaurora.org>]

Add interconnect support in dwc3-qcom driver to vote for bus
bandwidth.

This requires for two different paths - from USB master to
DDR slave. The other is from APPS master to USB slave.

Signed-off-by: Chandana Kishori Chiluveru <cchiluve@codeaurora.org>
---
 drivers/usb/dwc3/dwc3-qcom.c | 147 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 145 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
index 184df4d..4b8c2ae 100644
--- a/drivers/usb/dwc3/dwc3-qcom.c
+++ b/drivers/usb/dwc3/dwc3-qcom.c
@@ -14,6 +14,7 @@
 #include <linux/extcon.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/interconnect.h>
 #include <linux/phy/phy.h>
 #include <linux/usb/of.h>
 #include <linux/reset.h>
@@ -38,6 +39,9 @@
 #define PWR_EVNT_LPM_IN_L2_MASK			BIT(4)
 #define PWR_EVNT_LPM_OUT_L2_MASK		BIT(5)
 
+#define USB_DDR "usb-ddr"
+#define APPS_USB "apps-usb"
+
 struct dwc3_qcom {
 	struct device		*dev;
 	void __iomem		*qscratch_base;
@@ -59,8 +63,13 @@ struct dwc3_qcom {
 	enum usb_dr_mode	mode;
 	bool			is_suspended;
 	bool			pm_suspended;
+	struct icc_path *usb_ddr_icc_path;
+	struct icc_path *apps_usb_icc_path;
 };
 
+static int usb_interconnect_enable(struct dwc3_qcom *qcom);
+static int usb_interconnect_disable(struct dwc3_qcom *qcom);
+
 static inline void dwc3_qcom_setbits(void __iomem *base, u32 offset, u32 val)
 {
 	u32 reg;
@@ -222,7 +231,7 @@ static void dwc3_qcom_enable_interrupts(struct dwc3_qcom *qcom)
 static int dwc3_qcom_suspend(struct dwc3_qcom *qcom)
 {
 	u32 val;
-	int i;
+	int i, ret;
 
 	if (qcom->is_suspended)
 		return 0;
@@ -234,6 +243,11 @@ static int dwc3_qcom_suspend(struct dwc3_qcom *qcom)
 	for (i = qcom->num_clocks - 1; i >= 0; i--)
 		clk_disable_unprepare(qcom->clks[i]);
 
+	/* Remove bus voting */
+	ret = usb_interconnect_disable(qcom);
+	if (ret)
+		dev_err(qcom->dev, "bus bw voting failed %d\n", ret);
+
 	qcom->is_suspended = true;
 	dwc3_qcom_enable_interrupts(qcom);
 
@@ -259,6 +273,11 @@ static int dwc3_qcom_resume(struct dwc3_qcom *qcom)
 		}
 	}
 
+	/* Add bus voting */
+	ret = usb_interconnect_enable(qcom);
+	if (ret)
+		dev_err(qcom->dev, "bus bw voting failed %d\n", ret);
+
 	/* Clear existing events from PHY related to L2 in/out */
 	dwc3_qcom_setbits(qcom->qscratch_base, PWR_EVNT_IRQ_STAT_REG,
 			  PWR_EVNT_LPM_IN_L2_MASK | PWR_EVNT_LPM_OUT_L2_MASK);
@@ -409,6 +428,116 @@ static int dwc3_qcom_clk_init(struct dwc3_qcom *qcom, int count)
 	return 0;
 }
 
+/* Interconnect path bandwidths in KBps */
+#define USB_MEMORY_AVG_HS_BW 240000
+#define USB_MEMORY_PEAK_HS_BW 700000
+#define USB_MEMORY_AVG_SS_BW  1000000
+#define USB_MEMORY_PEAK_SS_BW 2500000
+#define APPS_USB_AVG_BW 0
+#define APPS_USB_PEAK_BW 40000
+
+/**
+ * usb_interconnect_init() - Request to get interconnect path handle
+ * @qcom:			Pointer to the concerned usb core.
+ *
+ */
+static int usb_interconnect_init(struct dwc3_qcom *qcom)
+{
+	struct device *dev = qcom->dev;
+
+	qcom->usb_ddr_icc_path = of_icc_get(dev, USB_DDR);
+	if (IS_ERR(qcom->usb_ddr_icc_path)) {
+		dev_err(dev, "Error: (%ld) failed getting %s path\n",
+			PTR_ERR(qcom->usb_ddr_icc_path), USB_DDR);
+		return PTR_ERR(qcom->usb_ddr_icc_path);
+	}
+
+	qcom->apps_usb_icc_path = of_icc_get(dev, APPS_USB);
+	if (IS_ERR(qcom->apps_usb_icc_path)) {
+		dev_err(dev, "Error: (%ld) failed getting %s path\n",
+				PTR_ERR(qcom->apps_usb_icc_path), APPS_USB);
+		return PTR_ERR(qcom->usb_ddr_icc_path);
+	}
+
+	return 0;
+}
+
+/**
+ * geni_interconnect_exit() - Request to release interconnect path handle
+ * @qcom:			Pointer to the concerned usb core.
+ *
+ * This function is used to release interconnect path handle.
+ */
+static void usb_interconnect_exit(struct dwc3_qcom *qcom)
+{
+	icc_put(qcom->usb_ddr_icc_path);
+	icc_put(qcom->apps_usb_icc_path);
+}
+
+/* Currently we only use bandwidth level, so just "enable" interconnects */
+static int usb_interconnect_enable(struct dwc3_qcom *qcom)
+{
+	struct dwc3 *dwc;
+	int ret;
+
+	dwc = platform_get_drvdata(qcom->dwc3);
+	if (!dwc) {
+		dev_err(qcom->dev, "Failed to get dwc3 device\n");
+		return -EPROBE_DEFER;
+	}
+
+	if (dwc->maximum_speed == USB_SPEED_SUPER) {
+		ret = icc_set_bw(qcom->usb_ddr_icc_path,
+			USB_MEMORY_AVG_SS_BW, USB_MEMORY_PEAK_SS_BW);
+		if (ret)
+			return ret;
+	} else {
+		ret = icc_set_bw(qcom->usb_ddr_icc_path,
+			USB_MEMORY_AVG_HS_BW, USB_MEMORY_PEAK_HS_BW);
+		if (ret)
+			return ret;
+	}
+
+	ret = icc_set_bw(qcom->apps_usb_icc_path,
+		APPS_USB_AVG_BW, APPS_USB_PEAK_BW);
+	if (ret)
+		goto err_disable_mem_path;
+
+	return 0;
+
+err_disable_mem_path:
+	icc_set_bw(qcom->usb_ddr_icc_path, 0, 0);
+
+	return ret;
+}
+
+/* To disable an interconnect, we just its bandwidth to 0 */
+static int usb_interconnect_disable(struct dwc3_qcom *qcom)
+{
+	struct dwc3 *dwc = platform_get_drvdata(qcom->dwc3);
+	int ret;
+
+	ret = icc_set_bw(qcom->usb_ddr_icc_path, 0, 0);
+	if (ret)
+		return ret;
+
+	ret = icc_set_bw(qcom->apps_usb_icc_path, 0, 0);
+	if (ret)
+		goto err_reenable_memory_path;
+
+	return 0;       /* Success */
+
+	/* Re-enable things in the event of an error */
+err_reenable_memory_path:
+	if (dwc->maximum_speed == USB_SPEED_SUPER)
+		icc_set_bw(qcom->usb_ddr_icc_path,
+			USB_MEMORY_AVG_SS_BW, USB_MEMORY_PEAK_SS_BW);
+	else
+		icc_set_bw(qcom->usb_ddr_icc_path,
+			USB_MEMORY_AVG_HS_BW, USB_MEMORY_PEAK_HS_BW);
+
+	return ret;
+}
 static int dwc3_qcom_probe(struct platform_device *pdev)
 {
 	struct device_node	*np = pdev->dev.of_node, *dwc3_np;
@@ -494,6 +623,17 @@ static int dwc3_qcom_probe(struct platform_device *pdev)
 		goto depopulate;
 	}
 
+	ret = usb_interconnect_init(qcom);
+	if (ret) {
+		dev_err(dev, "failed to get interconnect handle ret:%d\n", ret);
+		goto depopulate;
+	}
+	ret = usb_interconnect_enable(qcom);
+	if (ret) {
+		dev_err(qcom->dev, "bus bw voting failed %d\n", ret);
+		goto interconnect_exit;
+	}
+
 	qcom->mode = usb_get_dr_mode(&qcom->dwc3->dev);
 
 	/* enable vbus override for device mode */
@@ -503,7 +643,7 @@ static int dwc3_qcom_probe(struct platform_device *pdev)
 	/* register extcon to override sw_vbus on Vbus change later */
 	ret = dwc3_qcom_register_extcon(qcom);
 	if (ret)
-		goto depopulate;
+		goto interconnect_exit;
 
 	device_init_wakeup(&pdev->dev, 1);
 	qcom->is_suspended = false;
@@ -513,6 +653,8 @@ static int dwc3_qcom_probe(struct platform_device *pdev)
 
 	return 0;
 
+interconnect_exit:
+	usb_interconnect_exit(qcom);
 depopulate:
 	of_platform_depopulate(&pdev->dev);
 clk_disable:
@@ -540,6 +682,7 @@ static int dwc3_qcom_remove(struct platform_device *pdev)
 	}
 	qcom->num_clocks = 0;
 
+	usb_interconnect_exit(qcom);
 	reset_control_assert(qcom->resets);
 
 	pm_runtime_allow(dev);
-- 
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