[PATCH 5.15 38/80] usb: dwc3: core: Fix system suspend on TI AM62 platforms

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Roger Quadros <rogerq@kernel.org>

[ 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@vger.kernel.org # v6.9+
Fixes: 6d735722063a ("usb: dwc3: core: Prevent phy suspend during init")
Link: https://lore.kernel.org/all/1519dbe7-73b6-4afc-bfe3-23f4f75d772f@kernel.org/
Signed-off-by: Roger Quadros <rogerq@kernel.org>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Tested-by: Markus Schneider-Pargmann <msp@baylibre.com>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Link: https://lore.kernel.org/r/20241011-am62-lpm-usb-v3-1-562d445625b5@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/dwc3/core.c | 19 +++++++++++++++++++
 drivers/usb/dwc3/core.h |  3 +++
 2 files changed, 22 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 6c740dc633e7c..0ca06a3ab7179 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1796,6 +1796,11 @@ 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))
@@ -1843,6 +1848,15 @@ 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;
 }
 
@@ -1905,6 +1919,11 @@ 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 7e7820ce21bf5..3d434c110bdb6 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1085,6 +1085,8 @@ struct dwc3_scratchpad_array {
  * @dis_metastability_quirk: set to disable metastability quirk.
  * @dis_split_quirk: set to disable split boundary.
  * @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.
@@ -1300,6 +1302,7 @@ struct dwc3 {
 	unsigned		dis_split_quirk:1;
 	unsigned		async_callbacks:1;
 	unsigned		suspended:1;
+	unsigned		susphy_state:1;
 
 	u16			imod_interval;
 
-- 
2.43.0