[PATCH 2/2] usb: dwc2: Update reset method for host and device mode

[Kongyang Liu <seashell11234455@gmail.com>]

Starting from version 4.20a, there has been a change in the reset method.
A new bit, GRSTCTL_CSFTRST_DONE, has been introduced in the GRSTCTL
register to indicate whether the reset has been completed.

This patch mainly refers to the patch in the kernel.
Link: https://lore.kernel.org/all/9be2bb0c728da3dabf634c894f77e0e9709edeaa.1590040892.git.hminas@synopsys.com/

Signed-off-by: Kongyang Liu <seashell11234455@gmail.com>
---

 drivers/usb/common/dwc2_core.c    | 50 +++++++++++++++++++++++++++++++
 drivers/usb/common/dwc2_core.h    |  1 +
 drivers/usb/gadget/dwc2_udc_otg.c |  2 +-
 drivers/usb/host/dwc2.c           | 36 ++--------------------
 4 files changed, 55 insertions(+), 34 deletions(-)

diff --git a/drivers/usb/common/dwc2_core.c b/drivers/usb/common/dwc2_core.c
index 2fa11fd59d..323326e05d 100644
--- a/drivers/usb/common/dwc2_core.c
+++ b/drivers/usb/common/dwc2_core.c
@@ -10,6 +10,56 @@
 
 #include "dwc2_core.h"
 
+int dwc2_core_reset(struct dwc2_core_regs *regs)
+{
+	u32 snpsid;
+	int ret;
+	bool host_mode = false;
+
+	if (!(readl(&regs->global_regs.gotgctl) & GOTGCTL_CONID_B) ||
+	    (readl(&regs->global_regs.gusbcfg) & GUSBCFG_FORCEDEVMODE))
+		host_mode = true;
+
+	/* Core Soft Reset */
+	snpsid = readl(&regs->global_regs.gsnpsid);
+	writel(GRSTCTL_CSFTRST, &regs->global_regs.grstctl);
+	if (FIELD_GET(GSNPSID_VER_MASK, snpsid) < 0x420a) {
+		ret = wait_for_bit_le32(&regs->global_regs.grstctl, GRSTCTL_CSFTRST,
+					false, 1000, false);
+		if (ret) {
+			log_warning("%s: Waiting for GRSTCTL_CSFTRST timeout\n", __func__);
+			return -EBUSY;
+		}
+	} else {
+		ret = wait_for_bit_le32(&regs->global_regs.grstctl, GRSTCTL_CSFTRST_DONE,
+					true, 1000, false);
+		if (ret) {
+			log_warning("%s: Waiting for GRSTCTL_CSFTRST_DONE timeout\n", __func__);
+			return -EBUSY;
+		}
+		clrsetbits_le32(&regs->global_regs.grstctl, GRSTCTL_CSFTRST, GRSTCTL_CSFTRST_DONE);
+	}
+
+	/* Wait for AHB master IDLE state. */
+	ret = wait_for_bit_le32(&regs->global_regs.grstctl, GRSTCTL_AHBIDLE,
+				true, 1000, false);
+	if (ret) {
+		log_warning("%s: Waiting for GRSTCTL_AHBIDLE timeout\n", __func__);
+		return -EBUSY;
+	}
+
+	if (host_mode) {
+		ret = wait_for_bit_le32(&regs->global_regs.gintsts, GINTSTS_CURMODE_HOST,
+					host_mode, 1000, false);
+		if (ret) {
+			log_warning("%s: Waiting for GINTSTS_CURMODE_HOST timeout\n", __func__);
+			return -EBUSY;
+		}
+	}
+
+	return 0;
+}
+
 void dwc2_flush_tx_fifo(struct dwc2_core_regs *regs, const int num)
 {
 	int ret;
diff --git a/drivers/usb/common/dwc2_core.h b/drivers/usb/common/dwc2_core.h
index 8303153446..dd6937dd30 100644
--- a/drivers/usb/common/dwc2_core.h
+++ b/drivers/usb/common/dwc2_core.h
@@ -123,6 +123,7 @@ struct dwc2_core_regs {
 	u8  ep_fifo[16][0x1000];
 };
 
+int dwc2_core_reset(struct dwc2_core_regs *regs);
 void dwc2_flush_tx_fifo(struct dwc2_core_regs *regs, const int num);
 void dwc2_flush_rx_fifo(struct dwc2_core_regs *regs);
 
diff --git a/drivers/usb/gadget/dwc2_udc_otg.c b/drivers/usb/gadget/dwc2_udc_otg.c
index ac902b325a..727832e859 100644
--- a/drivers/usb/gadget/dwc2_udc_otg.c
+++ b/drivers/usb/gadget/dwc2_udc_otg.c
@@ -469,7 +469,7 @@ static void reconfig_usbd(struct dwc2_udc *dev)
 	u32 max_hw_ep;
 	int pdata_hw_ep;
 
-	writel(GRSTCTL_CSFTRST, &reg->global_regs.grstctl);
+	dwc2_core_reset(reg);
 
 	debug("Resetting OTG controller\n");
 
diff --git a/drivers/usb/host/dwc2.c b/drivers/usb/host/dwc2.c
index 93ed9604c2..6e73a3d90d 100644
--- a/drivers/usb/host/dwc2.c
+++ b/drivers/usb/host/dwc2.c
@@ -109,36 +109,6 @@ static void init_fslspclksel(struct dwc2_core_regs *regs)
 			FIELD_PREP(HCFG_FSLSPCLKSEL_MASK, phyclk));
 }
 
-/*
- * Do core a soft reset of the core.  Be careful with this because it
- * resets all the internal state machines of the core.
- */
-static void dwc_otg_core_reset(struct udevice *dev,
-			       struct dwc2_core_regs *regs)
-{
-	int ret;
-
-	/* Wait for AHB master IDLE state. */
-	ret = wait_for_bit_le32(&regs->global_regs.grstctl, GRSTCTL_AHBIDLE,
-				true, 1000, false);
-	if (ret)
-		dev_info(dev, "%s: Timeout!\n", __func__);
-
-	/* Core Soft Reset */
-	writel(GRSTCTL_CSFTRST, &regs->global_regs.grstctl);
-	ret = wait_for_bit_le32(&regs->global_regs.grstctl, GRSTCTL_CSFTRST,
-				false, 1000, false);
-	if (ret)
-		dev_info(dev, "%s: Timeout!\n", __func__);
-
-	/*
-	 * Wait for core to come out of reset.
-	 * NOTE: This long sleep is _very_ important, otherwise the core will
-	 *       not stay in host mode after a connector ID change!
-	 */
-	mdelay(100);
-}
-
 #if CONFIG_IS_ENABLED(DM_USB) && defined(CONFIG_DM_REGULATOR)
 static int dwc_vbus_supply_init(struct udevice *dev)
 {
@@ -311,7 +281,7 @@ static void dwc_otg_core_init(struct udevice *dev)
 	writel(usbcfg, &regs->global_regs.gusbcfg);
 
 	/* Reset the Controller */
-	dwc_otg_core_reset(dev, regs);
+	dwc2_core_reset(regs);
 
 	/*
 	 * This programming sequence needs to happen in FS mode before
@@ -323,7 +293,7 @@ static void dwc_otg_core_init(struct udevice *dev)
 	setbits_le32(&regs->global_regs.gusbcfg, GUSBCFG_PHYSEL);
 
 	/* Reset after a PHY select */
-	dwc_otg_core_reset(dev, regs);
+	dwc2_core_reset(regs);
 
 	/*
 	 * Program DCFG.DevSpd or HCFG.FSLSPclkSel to 48Mhz in FS.
@@ -369,7 +339,7 @@ static void dwc_otg_core_init(struct udevice *dev)
 	writel(usbcfg, &regs->global_regs.gusbcfg);
 
 	/* Reset after setting the PHY parameters */
-	dwc_otg_core_reset(dev, regs);
+	dwc2_core_reset(regs);
 #endif
 
 	usbcfg = readl(&regs->global_regs.gusbcfg);
-- 
2.41.0