[PATCH 0/3] phy: qcom: carry live SS-link state without growing enum phy_mode

[PATCH 0/3] phy: qcom: carry live SS-link state without growing enum phy_mode

[Tapas Rana]

QMP PHY drivers always enable receiver detection (ARCVR_DTCT_EN) in
autonomous mode, and additionally enable LFPS detection (ALFPS_DTCT_EN)
when a SuperSpeed link is present; otherwise they fall back to
receiver-detect event selection (ARCVR_DTCT_EVENT_SEL). This choice is
made by comparing phy_mode against
PHY_MODE_USB_HOST_SS/PHY_MODE_USB_DEVICE_SS. However, dwc3 core only
calls phy_set_mode()/phy_set_mode_ext() with the base
PHY_MODE_USB_HOST or PHY_MODE_USB_DEVICE, never the _SS/_HS/_FS/_LS
submodes. As a result, the comparison is always false and the PHY
always falls back to ARCVR_DTCT_EVENT_SEL, the legacy USB2
receiver-detect path, regardless of actual link state.

Add a dedicated qcom_usb_ss_state submode and carry it through the
generic submode argument phy_set_mode_ext() already defines for this
purpose, instead of adding more values to the already-overloaded
phy_mode USB host/device submode list.

Patch 1 adds the shared enum qcom_usb_ss_state (UNKNOWN/PRESENT/
ABSENT) as the submode contract. Patch 2 makes
phy-qcom-qmp-combo.c switch on it instead of on phy_mode. Patch 3
makes dwc3-qcom.c sample live SuperSpeed child-device presence at
suspend entry and pass it down.

The contract is intentionally generic so phy-qcom-qmp-usb.c can adopt
it the same way for the gadget-side case in a follow-up series,
without a second mechanism.

Tested on an x1e80100 CRD. On a host port with a SuperSpeed hub
attached, suspended the system and then connected a SuperSpeed USB
pendrive to the hub; confirmed ALFPS_DTCT_EN is set instead of the
legacy ARCVR_DTCT_EVENT_SEL mask. Repeated the same sequence on the
USB-OTG capable port with the same result. As a cross-check, repeated
both suspend scenarios with a High-Speed-only pendrive attached, and
again with nothing attached, and confirmed the PHY falls back to
ARCVR_DTCT_EVENT_SEL in both cases, as expected when no SuperSpeed
device is present.

This series spans both the generic PHY framework tree and the USB/DWC3
tree: patch 1 adds a new header, patch 2 depends on patch 1 and touches
drivers/phy/qualcomm/, patch 3 depends on patches 1-2 and touches
drivers/usb/dwc3/. All three should be merged in order and ideally
through the same tree (or with an immutable branch) to avoid a window
where dwc3-qcom.c references a submode phy-qcom-qmp-combo.c doesn't
yet switch on. ARM/QUALCOMM MAILING LIST (linux-arm-msm@vger.kernel.org)
is Cc'd on all three patches since it covers both directories.

Tapas Rana (3):
  phy: qcom-qmp-usb-ss: add shared SS-link-state submode contract
  phy: qcom: qmp-combo: Select LFPS detect only when SS link is
    confirmed present
  usb: dwc3: qcom: pass live SS-link state into PHY at suspend entry

 drivers/phy/qualcomm/phy-qcom-qmp-combo.c | 27 +++++++++++++++--
 drivers/usb/dwc3/dwc3-qcom.c              | 36 ++++++++++++++++++++++-
 include/linux/phy/phy-qcom-qmp-usb-ss.h   | 17 +++++++++++
 3 files changed, 76 insertions(+), 4 deletions(-)
 create mode 100644 include/linux/phy/phy-qcom-qmp-usb-ss.h

-- 
2.43.0

[PATCH 1/3] phy: qcom-qmp-usb-ss: add shared SS-link-state submode contract

[Tapas Rana]

dwc3 core only calls phy_set_mode()/phy_set_mode_ext() with the base
PHY_MODE_USB_HOST or PHY_MODE_USB_DEVICE. It never passes the
PHY_MODE_USB_{HOST,DEVICE}_SS/HS/FS/LS submode values to any PHY
driver. However, QMP PHY drivers need to know whether a SuperSpeed
link is present to select the correct autonomous-mode wake interrupt
mask, and phy_mode alone cannot carry that.

Add enum qcom_usb_ss_state (UNKNOWN/PRESENT/ABSENT) and carry it
through the existing submode argument of phy_set_mode_ext(), instead
of extending enum phy_mode further. UNKNOWN is the default so callers
that do not yet pass a real value keep current behavior.

Signed-off-by: Tapas Rana <tapas.rana@oss.qualcomm.com>
---
 include/linux/phy/phy-qcom-qmp-usb-ss.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
 create mode 100644 include/linux/phy/phy-qcom-qmp-usb-ss.h

diff --git a/include/linux/phy/phy-qcom-qmp-usb-ss.h b/include/linux/phy/phy-qcom-qmp-usb-ss.h
new file mode 100644
index 000000000000..4da4d71e977d
--- /dev/null
+++ b/include/linux/phy/phy-qcom-qmp-usb-ss.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Shared submode contract between dwc3-qcom glue and the Qualcomm QMP
+ * USB3/combo PHY driver for communicating live SuperSpeed link presence
+ * at suspend-entry, via phy_set_mode_ext()'s submode argument.
+ */
+
+#ifndef _PHY_QCOM_QMP_USB_SS_H_
+#define _PHY_QCOM_QMP_USB_SS_H_
+
+enum qcom_usb_ss_state {
+	QCOM_USB_SS_UNKNOWN = 0,
+	QCOM_USB_SS_PRESENT,
+	QCOM_USB_SS_ABSENT,
+};
+
+#endif /* _PHY_QCOM_QMP_USB_SS_H_ */
-- 
2.43.0

[PATCH 2/3] phy: qcom: qmp-combo: Select LFPS detect only when SS link is confirmed present

[Tapas Rana]

qmp_combo_enable_autonomous_mode() selects the autonomous-mode wake
interrupt mask by comparing qmp->phy_mode against
PHY_MODE_USB_HOST_SS/PHY_MODE_USB_DEVICE_SS. However, this driver's
set_mode() only ever stores PHY_MODE_USB_HOST or PHY_MODE_USB_DEVICE,
since dwc3 core and dwc3-qcom never pass the _SS variants. As a
result, the comparison is always false and the PHY always falls back
to the ARCVR_DTCT_EN | ARCVR_DTCT_EVENT_SEL mask instead of also
enabling ALFPS_DTCT_EN, regardless of whether a SuperSpeed device is
attached.

Store the qcom_usb_ss_state submode (added in the previous patch)
alongside phy_mode in qmp_combo_usb_set_mode(), and switch
qmp_combo_enable_autonomous_mode() on it instead of on phy_mode, so
LFPS detection is selected only when a SuperSpeed link is confirmed
present.

Signed-off-by: Tapas Rana <tapas.rana@oss.qualcomm.com>
---
 drivers/phy/qualcomm/phy-qcom-qmp-combo.c | 27 ++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-combo.c b/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
index aa9dc9716574..813a0955c591 100644
--- a/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
+++ b/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
@@ -27,6 +27,7 @@
 #include <drm/bridge/aux-bridge.h>
 
 #include <dt-bindings/phy/phy-qcom-qmp.h>
+#include <linux/phy/phy-qcom-qmp-usb-ss.h>
 
 #include "phy-qcom-qmp-common.h"
 
@@ -2630,6 +2631,7 @@ struct qmp_combo {
 
 	struct phy *usb_phy;
 	enum phy_mode phy_mode;
+	enum qcom_usb_ss_state  ss_state;
 	unsigned int usb_init_count;
 
 	struct phy *dp_phy;
@@ -4518,6 +4520,16 @@ static int qmp_combo_usb_set_mode(struct phy *phy, enum phy_mode mode, int submo
 
 	qmp->phy_mode = mode;
 
+	switch (submode) {
+	case QCOM_USB_SS_PRESENT:
+	case QCOM_USB_SS_ABSENT:
+		qmp->ss_state = submode;
+		break;
+	default:
+		qmp->ss_state = QCOM_USB_SS_UNKNOWN;
+		break;
+	}
+
 	return 0;
 }
 
@@ -4672,11 +4684,20 @@ static void qmp_combo_enable_autonomous_mode(struct qmp_combo *qmp)
 	void __iomem *pcs_aon = qmp->pcs_aon;
 	u32 intr_mask;
 
-	if (qmp->phy_mode == PHY_MODE_USB_HOST_SS ||
-	    qmp->phy_mode == PHY_MODE_USB_DEVICE_SS)
+	/*
+	 * Use LFPS detection only when a SuperSpeed device is known to be
+	 * present. For absent or unknown state, use receiver detection.
+	 */
+	switch (qmp->ss_state) {
+	case QCOM_USB_SS_PRESENT:
 		intr_mask = ARCVR_DTCT_EN | ALFPS_DTCT_EN;
-	else
+		break;
+	case QCOM_USB_SS_ABSENT:
+	case QCOM_USB_SS_UNKNOWN:
+	default:
 		intr_mask = ARCVR_DTCT_EN | ARCVR_DTCT_EVENT_SEL;
+		break;
+	}
 
 	/* Clear any pending interrupts status */
 	qphy_setbits(pcs_usb, cfg->regs[QPHY_PCS_LFPS_RXTERM_IRQ_CLEAR], IRQ_CLEAR);
-- 
2.43.0

[PATCH 3/3] usb: dwc3: qcom: pass live SS-link state into PHY at suspend entry

[Tapas Rana]

dwc3_qcom_suspend() puts each host port into autonomous/wake mode
without ever telling the PHY whether a SuperSpeed device is currently
attached. qmp_combo_enable_autonomous_mode(), made SS-aware in the
previous patch, therefore has no live signal to act on and always
sees QCOM_USB_SS_UNKNOWN, falling back to the legacy receiver-detect
mask regardless of actual link state.

Add dwc3_qcom_read_ss_state() to check each port's USB3 roothub for
an attached child device running at SuperSpeed or above, and pass the
result as the submode argument of phy_set_mode_ext() so the PHY can
select LFPS detection when appropriate.

Signed-off-by: Tapas Rana <tapas.rana@oss.qualcomm.com>
---
 drivers/usb/dwc3/dwc3-qcom.c | 36 +++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
index ac68b4218b56..d4ba095e47eb 100644
--- a/drivers/usb/dwc3/dwc3-qcom.c
+++ b/drivers/usb/dwc3/dwc3-qcom.c
@@ -19,6 +19,7 @@
 #include <linux/iopoll.h>
 #include <linux/usb/hcd.h>
 #include <linux/usb.h>
+#include <linux/phy/phy-qcom-qmp-usb-ss.h>
 #include "core.h"
 #include "glue.h"
 
@@ -66,6 +67,7 @@ struct dwc3_qcom_port {
 	int			dm_hs_phy_irq;
 	int			ss_phy_irq;
 	enum usb_device_speed	usb2_speed;
+	enum qcom_usb_ss_state  ss_state;
 };
 
 struct dwc3_qcom {
@@ -251,6 +253,34 @@ static enum usb_device_speed dwc3_qcom_read_usb2_speed(struct dwc3_qcom *qcom, i
 	return udev->speed;
 }
 
+static enum qcom_usb_ss_state dwc3_qcom_read_ss_state(struct dwc3_qcom *qcom, int port_index)
+{
+	struct usb_device *udev;
+	struct usb_hcd __maybe_unused *hcd, *usb3_hcd;
+	struct dwc3 *dwc = &qcom->dwc;
+
+	/*
+	 * FIXME: Fix this layering violation.
+	 */
+	hcd = platform_get_drvdata(dwc->xhci);
+	if (!hcd)
+		return QCOM_USB_SS_ABSENT;
+
+#ifdef CONFIG_USB
+	usb3_hcd = hcd->shared_hcd ? hcd->shared_hcd : hcd;
+	if (!usb3_hcd->self.root_hub)
+		return QCOM_USB_SS_ABSENT;
+
+	udev = usb_hub_find_child(usb3_hcd->self.root_hub, port_index + 1);
+#else
+	udev = NULL;
+#endif
+	if (!udev)
+		return QCOM_USB_SS_ABSENT;
+
+	return udev->speed >= USB_SPEED_SUPER ? QCOM_USB_SS_PRESENT : QCOM_USB_SS_ABSENT;
+}
+
 static void dwc3_qcom_enable_wakeup_irq(int irq, unsigned int polarity)
 {
 	if (!irq)
@@ -359,8 +389,12 @@ static int dwc3_qcom_suspend(struct dwc3_qcom *qcom, bool wakeup)
 	 * freezable workqueue.
 	 */
 	if (dwc3_qcom_is_host(qcom) && wakeup) {
-		for (i = 0; i < qcom->num_ports; i++)
+		for (i = 0; i < qcom->num_ports; i++) {
 			qcom->ports[i].usb2_speed = dwc3_qcom_read_usb2_speed(qcom, i);
+			qcom->ports[i].ss_state = dwc3_qcom_read_ss_state(qcom, i);
+			phy_set_mode_ext(qcom->dwc.usb3_generic_phy[i], PHY_MODE_USB_HOST,
+					 qcom->ports[i].ss_state);
+		}
 		dwc3_qcom_enable_interrupts(qcom);
 	}
 
-- 
2.43.0