Patch "usb: dwc3: core: Fix system suspend on TI AM62 platforms" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    usb: dwc3: core: Fix system suspend on TI AM62 platforms

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     usb-dwc3-core-fix-system-suspend-on-ti-am62-platform.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 7424de57ecea906d4e6e15ac9aeb2fc78939fedd
Author: Roger Quadros <rogerq@xxxxxxxxxx>
Date:   Fri Oct 11 13:53:24 2024 +0300

    usb: dwc3: core: Fix system suspend on TI AM62 platforms
    
    [ Upstream commit 705e3ce37bccdf2ed6f848356ff355f480d51a91 ]
    
    Since commit 6d735722063a ("usb: dwc3: core: Prevent phy suspend during init"),
    system suspend is broken on AM62 TI platforms.
    
    Before that commit, both DWC3_GUSB3PIPECTL_SUSPHY and DWC3_GUSB2PHYCFG_SUSPHY
    bits (hence forth called 2 SUSPHY bits) were being set during core
    initialization and even during core re-initialization after a system
    suspend/resume.
    
    These bits are required to be set for system suspend/resume to work correctly
    on AM62 platforms.
    
    Since that commit, the 2 SUSPHY bits are not set for DEVICE/OTG mode if gadget
    driver is not loaded and started.
    For Host mode, the 2 SUSPHY bits are set before the first system suspend but
    get cleared at system resume during core re-init and are never set again.
    
    This patch resovles these two issues by ensuring the 2 SUSPHY bits are set
    before system suspend and restored to the original state during system resume.
    
    Cc: stable@xxxxxxxxxxxxxxx # v6.9+
    Fixes: 6d735722063a ("usb: dwc3: core: Prevent phy suspend during init")
    Link: https://lore.kernel.org/all/1519dbe7-73b6-4afc-bfe3-23f4f75d772f@xxxxxxxxxx/
    Signed-off-by: Roger Quadros <rogerq@xxxxxxxxxx>
    Acked-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>
    Tested-by: Markus Schneider-Pargmann <msp@xxxxxxxxxxxx>
    Reviewed-by: Dhruva Gole <d-gole@xxxxxx>
    Link: https://lore.kernel.org/r/20241011-am62-lpm-usb-v3-1-562d445625b5@xxxxxxxxxx
    Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index af851e4e8c8a7..8cbe19574bbcb 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -2106,6 +2106,11 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
 {
 	u32 reg;
 
+	dwc->susphy_state = (dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0)) &
+			    DWC3_GUSB2PHYCFG_SUSPHY) ||
+			    (dwc3_readl(dwc->regs, DWC3_GUSB3PIPECTL(0)) &
+			    DWC3_GUSB3PIPECTL_SUSPHY);
+
 	switch (dwc->current_dr_role) {
 	case DWC3_GCTL_PRTCAP_DEVICE:
 		if (pm_runtime_suspended(dwc->dev))
@@ -2153,6 +2158,15 @@ 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;
 }
 
@@ -2215,6 +2229,11 @@ static int dwc3_resume_common(struct dwc3 *dwc, pm_message_t msg)
 		break;
 	}
 
+	if (!PMSG_IS_AUTO(msg)) {
+		/* restore SUSPHY state to that before system suspend. */
+		dwc3_enable_susphy(dwc, dwc->susphy_state);
+	}
+
 	return 0;
 }
 
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 420753205fafa..3325796f3cb45 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1127,6 +1127,8 @@ struct dwc3_scratchpad_array {
  * @sys_wakeup: set if the device may do system wakeup.
  * @wakeup_configured: set if the device is configured for remote wakeup.
  * @suspended: set to track suspend event due to U3/L2.
+ * @susphy_state: state of DWC3_GUSB2PHYCFG_SUSPHY + DWC3_GUSB3PIPECTL_SUSPHY
+ *		  before PM suspend.
  * @imod_interval: set the interrupt moderation interval in 250ns
  *			increments or 0 to disable.
  * @max_cfg_eps: current max number of IN eps used across all USB configs.
@@ -1351,6 +1353,7 @@ struct dwc3 {
 	unsigned		sys_wakeup:1;
 	unsigned		wakeup_configured:1;
 	unsigned		suspended:1;
+	unsigned		susphy_state:1;
 
 	u16			imod_interval;