usb: dwc3: Update core clock rate based on USB port speed.

Core clock rate can be reduced or increased based on operating
speeds. Controller starts in Super Speed mode (higher core clock
rate) and it will operate in super or high or full or low speed
upon device connection. Update the core clock rate based on bus
speed to allows system to operate in better low power state (such
as SVS1/SVS2 based on system configuration). High Speed rate for
core clock is programmed from dtsi. Super Speed rate will be used
if High speed core clock rate is not provided for backward
compatibility.

Change-Id: I265149d34de19ab50bd7f106a670a7112bfae384
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>

1 files changed, 51 insertions, 1 deletions

diff --git a/drivers/usb/dwc3/dwc3-msm.c b/drivers/usb/dwc3/dwc3-msm.c
index bc0e0184a917..7f40766dd197 100644
--- a/drivers/usb/dwc3/dwc3-msm.c
+++ b/drivers/usb/dwc3/dwc3-msm.c
@@ -156,6 +156,7 @@ struct dwc3_msm {
 	struct clk		*xo_clk;
 	struct clk		*core_clk;
 	long			core_clk_rate;
+	long			core_clk_rate_hs;
 	struct clk		*iface_clk;
 	struct clk		*sleep_clk;
 	struct clk		*utmi_clk;
@@ -195,6 +196,7 @@ struct dwc3_msm {
 	struct power_supply	*usb_psy;
 	struct work_struct	vbus_draw_work;
 	bool			in_host_mode;
+	enum usb_device_speed	max_rh_port_speed;
 	unsigned int		tx_fifo_size;
 	bool			vbus_active;
 	bool			suspend;
@@ -342,6 +344,23 @@ static inline void dwc3_msm_write_readback(void *base, u32 offset,
 			__func__, val, offset);
 }
 
+static bool dwc3_msm_is_ss_rhport_connected(struct dwc3_msm *mdwc)
+{
+	int i, num_ports;
+	u32 reg;
+
+	reg = dwc3_msm_read_reg(mdwc->base, USB3_HCSPARAMS1);
+	num_ports = HCS_MAX_PORTS(reg);
+
+	for (i = 0; i < num_ports; i++) {
+		reg = dwc3_msm_read_reg(mdwc->base, USB3_PORTSC + i*0x10);
+		if ((reg & PORT_CONNECT) && DEV_SUPERSPEED(reg))
+			return true;
+	}
+
+	return false;
+}
+
 static bool dwc3_msm_is_host_superspeed(struct dwc3_msm *mdwc)
 {
 	int i, num_ports;
@@ -2128,6 +2147,7 @@ static int dwc3_msm_suspend(struct dwc3_msm *mdwc)
 static int dwc3_msm_resume(struct dwc3_msm *mdwc)
 {
 	int ret;
+	long core_clk_rate;
 	struct dwc3 *dwc = platform_get_drvdata(mdwc->dwc3);
 
 	dev_dbg(mdwc->dev, "%s: exiting lpm\n", __func__);
@@ -2175,7 +2195,15 @@ static int dwc3_msm_resume(struct dwc3_msm *mdwc)
 	clk_prepare_enable(mdwc->iface_clk);
 	if (mdwc->noc_aggr_clk)
 		clk_prepare_enable(mdwc->noc_aggr_clk);
-	clk_set_rate(mdwc->core_clk, mdwc->core_clk_rate);
+
+	core_clk_rate = mdwc->core_clk_rate;
+	if (mdwc->in_host_mode && mdwc->max_rh_port_speed == USB_SPEED_HIGH) {
+		core_clk_rate = mdwc->core_clk_rate_hs;
+		dev_dbg(mdwc->dev, "%s: set hs core clk rate %ld\n", __func__,
+			core_clk_rate);
+	}
+
+	clk_set_rate(mdwc->core_clk, core_clk_rate);
 	clk_prepare_enable(mdwc->core_clk);
 
 	/* set Memory core: ON, Memory periphery: ON */
@@ -2496,6 +2524,11 @@ static int dwc3_msm_get_clk_gdsc(struct dwc3_msm *mdwc)
 	if (ret)
 		dev_err(mdwc->dev, "fail to set core_clk freq:%d\n", ret);
 
+	if (of_property_read_u32(mdwc->dev->of_node, "qcom,core-clk-rate-hs",
+				(u32 *)&mdwc->core_clk_rate_hs)) {
+		dev_dbg(mdwc->dev, "USB core-clk-rate-hs is not present\n");
+		mdwc->core_clk_rate_hs = mdwc->core_clk_rate;
+	}
 
 	mdwc->core_reset = devm_reset_control_get(mdwc->dev, "core_reset");
 	if (IS_ERR(mdwc->core_reset)) {
@@ -3166,10 +3199,26 @@ static int dwc3_msm_host_notifier(struct notifier_block *nb,
 	if (udev->parent && !udev->parent->parent &&
 			udev->dev.parent->parent == &dwc->xhci->dev) {
 		if (event == USB_DEVICE_ADD && udev->actconfig) {
+			if (!dwc3_msm_is_ss_rhport_connected(mdwc)) {
+				/*
+				 * Core clock rate can be reduced only if root
+				 * hub SS port is not enabled/connected.
+				 */
+				clk_set_rate(mdwc->core_clk,
+				mdwc->core_clk_rate_hs);
+				dev_dbg(mdwc->dev,
+					"set hs core clk rate %ld\n",
+					mdwc->core_clk_rate_hs);
+				mdwc->max_rh_port_speed = USB_SPEED_HIGH;
+			} else {
+				mdwc->max_rh_port_speed = USB_SPEED_SUPER;
+			}
+
 			if (udev->speed >= USB_SPEED_SUPER)
 				max_power = udev->actconfig->desc.bMaxPower * 8;
 			else
 				max_power = udev->actconfig->desc.bMaxPower * 2;
+
 			dev_dbg(mdwc->dev, "%s configured bMaxPower:%d (mA)\n",
 					dev_name(&udev->dev), max_power);
 
@@ -3181,6 +3230,7 @@ static int dwc3_msm_host_notifier(struct notifier_block *nb,
 			pval.intval = 0;
 			power_supply_set_property(mdwc->usb_psy,
 					POWER_SUPPLY_PROP_BOOST_CURRENT, &pval);
+			mdwc->max_rh_port_speed = USB_SPEED_UNKNOWN;
 		}
 	}