usb: dwc2: gadget: LPM flow fix

Added functionality to exit from L1 state by device initiation
using remote wakeup signaling, in case when function driver queuing
request while core in L1 state.

Fixes: 273d576 ("usb: dwc2: gadget: Add functionality to exit from LPM L1 state")
Fixes: 88b02f2 ("usb: dwc2: Add core state checking")
CC: stable@vger.kernel.org
Signed-off-by: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>
Link: https://lore.kernel.org/r/b4d9de5382375dddbf7ef6049d9a82066ad87d5d.1710166393.git.Minas.Harutyunyan@synopsys.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Minas Harutyunyan

drivers/usb/dwc2/core.h

@@ -1336,6 +1336,7 @@ int dwc2_backup_global_registers(struct dwc2_hsotg *hsotg);
 int dwc2_restore_global_registers(struct dwc2_hsotg *hsotg);
 
 void dwc2_enable_acg(struct dwc2_hsotg *hsotg);
+void dwc2_wakeup_from_lpm_l1(struct dwc2_hsotg *hsotg, bool remotewakeup);
 
 /* This function should be called on every hardware interrupt. */
 irqreturn_t dwc2_handle_common_intr(int irq, void *dev);

drivers/usb/dwc2/core_intr.c

@@ -323,10 +323,11 @@ static void dwc2_handle_session_req_intr(struct dwc2_hsotg *hsotg)
  * @hsotg: Programming view of DWC_otg controller
  *
  */
-static void dwc2_wakeup_from_lpm_l1(struct dwc2_hsotg *hsotg)
+void dwc2_wakeup_from_lpm_l1(struct dwc2_hsotg *hsotg, bool remotewakeup)
 {
 	u32 glpmcfg;
-	u32 i = 0;
+	u32 pcgctl;
+	u32 dctl;
 
 	if (hsotg->lx_state != DWC2_L1) {
 		dev_err(hsotg->dev, "Core isn't in DWC2_L1 state\n");
@@ -335,37 +336,57 @@ static void dwc2_wakeup_from_lpm_l1(struct dwc2_hsotg *hsotg)
 
 	glpmcfg = dwc2_readl(hsotg, GLPMCFG);
 	if (dwc2_is_device_mode(hsotg)) {
-		dev_dbg(hsotg->dev, "Exit from L1 state\n");
+		dev_dbg(hsotg->dev, "Exit from L1 state, remotewakeup=%d\n", remotewakeup);
 		glpmcfg &= ~GLPMCFG_ENBLSLPM;
-		glpmcfg &= ~GLPMCFG_HIRD_THRES_EN;
+		glpmcfg &= ~GLPMCFG_HIRD_THRES_MASK;
 		dwc2_writel(hsotg, glpmcfg, GLPMCFG);
 
-		do {
-			glpmcfg = dwc2_readl(hsotg, GLPMCFG);
+		pcgctl = dwc2_readl(hsotg, PCGCTL);
+		pcgctl &= ~PCGCTL_ENBL_SLEEP_GATING;
+		dwc2_writel(hsotg, pcgctl, PCGCTL);
 
-			if (!(glpmcfg & (GLPMCFG_COREL1RES_MASK |
-					 GLPMCFG_L1RESUMEOK | GLPMCFG_SLPSTS)))
-				break;
+		glpmcfg = dwc2_readl(hsotg, GLPMCFG);
+		if (glpmcfg & GLPMCFG_ENBESL) {
+			glpmcfg |= GLPMCFG_RSTRSLPSTS;
+			dwc2_writel(hsotg, glpmcfg, GLPMCFG);
+		}
+
+		if (remotewakeup) {
+			if (dwc2_hsotg_wait_bit_set(hsotg, GLPMCFG, GLPMCFG_L1RESUMEOK, 1000)) {
+				dev_warn(hsotg->dev, "%s: timeout GLPMCFG_L1RESUMEOK\n", __func__);
+				goto fail;
+				return;
+			}
+
+			dctl = dwc2_readl(hsotg, DCTL);
+			dctl |= DCTL_RMTWKUPSIG;
+			dwc2_writel(hsotg, dctl, DCTL);
 
-			udelay(1);
-		} while (++i < 200);
+			if (dwc2_hsotg_wait_bit_set(hsotg, GINTSTS, GINTSTS_WKUPINT, 1000)) {
+				dev_warn(hsotg->dev, "%s: timeout GINTSTS_WKUPINT\n", __func__);
+				goto fail;
+				return;
+			}
+		}
 
-		if (i == 200) {
-			dev_err(hsotg->dev, "Failed to exit L1 sleep state in 200us.\n");
+		glpmcfg = dwc2_readl(hsotg, GLPMCFG);
+		if (glpmcfg & GLPMCFG_COREL1RES_MASK || glpmcfg & GLPMCFG_SLPSTS ||
+		    glpmcfg & GLPMCFG_L1RESUMEOK) {
+			goto fail;
 			return;
 		}
-		dwc2_gadget_init_lpm(hsotg);
+
+		/* Inform gadget to exit from L1 */
+		call_gadget(hsotg, resume);
+		/* Change to L0 state */
+		hsotg->lx_state = DWC2_L0;
+		hsotg->bus_suspended = false;
+fail:		dwc2_gadget_init_lpm(hsotg);
 	} else {
 		/* TODO */
 		dev_err(hsotg->dev, "Host side LPM is not supported.\n");
 		return;
 	}
-
-	/* Change to L0 state */
-	hsotg->lx_state = DWC2_L0;
-
-	/* Inform gadget to exit from L1 */
-	call_gadget(hsotg, resume);
 }
 
 /*
@@ -386,7 +407,7 @@ static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
 	dev_dbg(hsotg->dev, "%s lxstate = %d\n", __func__, hsotg->lx_state);
 
 	if (hsotg->lx_state == DWC2_L1) {
-		dwc2_wakeup_from_lpm_l1(hsotg);
+		dwc2_wakeup_from_lpm_l1(hsotg, false);
 		return;
 	}
 

drivers/usb/dwc2/gadget.c

@@ -1415,6 +1415,10 @@ static int dwc2_hsotg_ep_queue(struct usb_ep *ep, struct usb_request *req,
 		ep->name, req, req->length, req->buf, req->no_interrupt,
 		req->zero, req->short_not_ok);
 
+	if (hs->lx_state == DWC2_L1) {
+		dwc2_wakeup_from_lpm_l1(hs, true);
+	}
+
 	/* Prevent new request submission when controller is suspended */
 	if (hs->lx_state != DWC2_L0) {
 		dev_dbg(hs->dev, "%s: submit request only in active state\n",