[PATCH] usb: dwc3: fix fault at system suspend if device was already runtime suspended

[Roger Quadros <rogerq@kernel.org>]

If the device was already runtime suspended then during system suspend
we cannot access the device registers else it will crash.

Also we cannot access any registers after dwc3_core_exit() on some
platforms so move the dwc3_enable_susphy() call to the top.

Cc: stable@vger.kernel.org # v5.15+
Reported-by: William McVicker <willmcvicker@google.com>
Closes: https://lore.kernel.org/all/ZyVfcUuPq56R2m1Y@google.com
Fixes: 705e3ce37bcc ("usb: dwc3: core: Fix system suspend on TI AM62 platforms")
Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
 drivers/usb/dwc3/core.c | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 427e5660f87c..98114c2827c0 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -2342,10 +2342,18 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
 	u32 reg;
 	int i;
 
-	dwc->susphy_state = (dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0)) &
-			    DWC3_GUSB2PHYCFG_SUSPHY) ||
-			    (dwc3_readl(dwc->regs, DWC3_GUSB3PIPECTL(0)) &
-			    DWC3_GUSB3PIPECTL_SUSPHY);
+	if (!pm_runtime_suspended(dwc->dev) && !PMSG_IS_AUTO(msg)) {
+		dwc->susphy_state = (dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0)) &
+				    DWC3_GUSB2PHYCFG_SUSPHY) ||
+				    (dwc3_readl(dwc->regs, DWC3_GUSB3PIPECTL(0)) &
+				    DWC3_GUSB3PIPECTL_SUSPHY);
+		/*
+		 * TI AM62 platform requires SUSPHY to be
+		 * enabled for system suspend to work.
+		 */
+		if (!dwc->susphy_state)
+			dwc3_enable_susphy(dwc, true);
+	}
 
 	switch (dwc->current_dr_role) {
 	case DWC3_GCTL_PRTCAP_DEVICE:
@@ -2398,15 +2406,6 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
 		break;
 	}
 
-	if (!PMSG_IS_AUTO(msg)) {
-		/*
-		 * TI AM62 platform requires SUSPHY to be
-		 * enabled for system suspend to work.
-		 */
-		if (!dwc->susphy_state)
-			dwc3_enable_susphy(dwc, true);
-	}
-
 	return 0;
 }
 

---
base-commit: 42f7652d3eb527d03665b09edac47f85fb600924
change-id: 20241102-am62-lpm-usb-fix-347dd86135c1

Best regards,
-- 
Roger Quadros <rogerq@kernel.org>