usb: dwc2: Force mode optimizations

If the dr_mode is USB_DR_MODE_OTG, forcing the mode is needed during
driver probe to get the host and device specific HW parameters. Then we
clear the force mode bits so that the core operates in OTG mode.

The force mode bits should not be touched at any other time during the
driver lifetime and they should be preserved whenever the GUSBCFG
register is written to. The force mode bit values will persist across
soft resets of the core.

If the dr_mode is either USB_DR_MODE_HOST or USB_DR_MODE_PERIPHERAL, the
force mode is set just once at probe to configure the core as either a
host or peripheral.

Given the above, we no longer need any other reset delays, force delays,
or any forced modes anywhere else in the driver. So replace all calls to
dwc2_core_reset_and_force_dr_mode() with dwc2_core_reset() and remove
all other unnecessary delays.

Also remove the dwc2_force_mode_if_needed() function since the "if
needed" part is already taken care of by the polling in
dwc2_force_mode().

Finally, remove all other calls to dwc2_clear_force_mode().

Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Vardan Mikayelyan <mvardan@synopsys.com>
Signed-off-by: Grigor Tovmasyan <tovmasya@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

1 files changed, 14 insertions, 47 deletions

diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c
index 280ecddf82cb..cf1faf2443d0 100644
--- a/drivers/usb/dwc2/core.c
+++ b/drivers/usb/dwc2/core.c
@@ -541,14 +541,14 @@ int dwc2_core_reset(struct dwc2_hsotg *hsotg, bool skip_wait)
 	return 0;
 }
 
-/*
- * Force the mode of the controller.
+/**
+ * dwc2_force_mode() - Force the mode of the controller.
  *
  * Forcing the mode is needed for two cases:
  *
  * 1) If the dr_mode is set to either HOST or PERIPHERAL we force the
  * controller to stay in a particular mode regardless of ID pin
- * changes. We do this usually after a core reset.
+ * changes. We do this once during probe.
  *
  * 2) During probe we want to read reset values of the hw
  * configuration registers that are only available in either host or
@@ -565,7 +565,7 @@ int dwc2_core_reset(struct dwc2_hsotg *hsotg, bool skip_wait)
  * the filter is configured and enabled. We poll the current mode of
  * the controller to account for this delay.
  */
-static bool dwc2_force_mode(struct dwc2_hsotg *hsotg, bool host)
+void dwc2_force_mode(struct dwc2_hsotg *hsotg, bool host)
 {
 	u32 gusbcfg;
 	u32 set;
@@ -577,17 +577,17 @@ static bool dwc2_force_mode(struct dwc2_hsotg *hsotg, bool host)
 	 * Force mode has no effect if the hardware is not OTG.
 	 */
 	if (!dwc2_hw_is_otg(hsotg))
-		return false;
+		return;
 
 	/*
 	 * If dr_mode is either peripheral or host only, there is no
 	 * need to ever force the mode to the opposite mode.
 	 */
 	if (WARN_ON(host && hsotg->dr_mode == USB_DR_MODE_PERIPHERAL))
-		return false;
+		return;
 
 	if (WARN_ON(!host && hsotg->dr_mode == USB_DR_MODE_HOST))
-		return false;
+		return;
 
 	gusbcfg = dwc2_readl(hsotg->regs + GUSBCFG);
 
@@ -599,7 +599,7 @@ static bool dwc2_force_mode(struct dwc2_hsotg *hsotg, bool host)
 	dwc2_writel(gusbcfg, hsotg->regs + GUSBCFG);
 
 	dwc2_wait_for_mode(hsotg, host);
-	return true;
+	return;
 }
 
 /**
@@ -615,6 +615,11 @@ void dwc2_clear_force_mode(struct dwc2_hsotg *hsotg)
 {
 	u32 gusbcfg;
 
+	if (!dwc2_hw_is_otg(hsotg))
+		return;
+
+	dev_dbg(hsotg->dev, "Clearing force mode bits\n");
+
 	gusbcfg = dwc2_readl(hsotg->regs + GUSBCFG);
 	gusbcfg &= ~GUSBCFG_FORCEHOSTMODE;
 	gusbcfg &= ~GUSBCFG_FORCEDEVMODE;
@@ -629,16 +634,13 @@ void dwc2_clear_force_mode(struct dwc2_hsotg *hsotg)
  */
 void dwc2_force_dr_mode(struct dwc2_hsotg *hsotg)
 {
-	bool ret;
-
 	switch (hsotg->dr_mode) {
 	case USB_DR_MODE_HOST:
-		ret = dwc2_force_mode(hsotg, true);
 		/*
 		 * NOTE: This is required for some rockchip soc based
 		 * platforms on their host-only dwc2.
 		 */
-		if (!ret)
+		if (!dwc2_hw_is_otg(hsotg))
 			msleep(50);
 
 		break;
@@ -656,25 +658,6 @@ void dwc2_force_dr_mode(struct dwc2_hsotg *hsotg)
 }
 
 /*
- * Do core a soft reset of the core.  Be careful with this because it
- * resets all the internal state machines of the core.
- *
- * Additionally this will apply force mode as per the hsotg->dr_mode
- * parameter.
- */
-int dwc2_core_reset_and_force_dr_mode(struct dwc2_hsotg *hsotg)
-{
-	int retval;
-
-	retval = dwc2_core_reset(hsotg, false);
-	if (retval)
-		return retval;
-
-	dwc2_force_dr_mode(hsotg);
-	return 0;
-}
-
-/*
  * dwc2_enable_acg - enable active clock gating feature
  */
 void dwc2_enable_acg(struct dwc2_hsotg *hsotg)
@@ -910,22 +893,6 @@ void dwc2_flush_rx_fifo(struct dwc2_hsotg *hsotg)
 	udelay(1);
 }
 
-/*
- * Forces either host or device mode if the controller is not
- * currently in that mode.
- *
- * Returns true if the mode was forced.
- */
-bool dwc2_force_mode_if_needed(struct dwc2_hsotg *hsotg, bool host)
-{
-	if (host && dwc2_is_host_mode(hsotg))
-		return false;
-	else if (!host && dwc2_is_device_mode(hsotg))
-		return false;
-
-	return dwc2_force_mode(hsotg, host);
-}
-
 bool dwc2_is_controller_alive(struct dwc2_hsotg *hsotg)
 {
 	if (dwc2_readl(hsotg->regs + GSNPSID) == 0xffffffff)