Some platforms gate the USB2 PHY power domain during deep sleep
(S3) even when device_may_wakeup is set, which causes the PHY
register state to be lost. The DWC3 fast resume path (taken when
device_may_wakeup is true) relies on phy_pm_runtime_get_sync() to
restore the PHY, but this is a no-op for PHY drivers that do not
implement runtime PM (e.g. the Qualcomm eUSB2 driver).
Add a new boolean quirk 'snps,reinit-phy-on-resume' that, when set,
forces a full phy_exit() + phy_init() cycle on each USB2 PHY during
the host-mode fast resume path. This ensures the PHY registers are
properly re-programmed after power loss.
Signed-off-by: Oliver White <redacted>
---
drivers/usb/dwc3/core.c | 25 +++++++++++++++++++++++++
drivers/usb/dwc3/core.h | 1 +
2 files changed, 26 insertions(+)
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 161a4d58b2ce..82baaab0d1d1 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1854,6 +1854,8 @@ static void dwc3_get_properties(struct dwc3 *dwc)
dwc->dis_split_quirk = device_property_read_bool(dev,
"snps,dis-split-quirk");
+ dwc->reinit_phy_on_resume = device_property_read_bool(dev,
+ "snps,reinit-phy-on-resume");
dwc->lpm_nyet_threshold = lpm_nyet_threshold;
dwc->tx_de_emphasis = tx_de_emphasis;
@@ -2561,6 +2563,29 @@ static int dwc3_resume_common(struct dwc3 *dwc, pm_message_t msg)
dwc3_writel(dwc, DWC3_GUSB2PHYCFG(i), reg);
}
+ /*
+ * Some platforms gate USB2 PHY power during deep sleep even
+ * when device_may_wakeup is true, causing register state to be
+ * lost. Re-initialize the PHY to ensure clean signalling.
+ */
+ if (dwc->reinit_phy_on_resume && !PMSG_IS_AUTO(msg)) {
+ for (i = 0; i < dwc->num_usb2_ports; i++) {
+ int ret;
+
+ ret = phy_exit(dwc->usb2_generic_phy[i]);
+ if (ret)
+ dev_warn_ratelimited(dwc->dev,
+ "failed to exit usb2 phy %d: %d\n",
+ i, ret);
+
+ ret = phy_init(dwc->usb2_generic_phy[i]);
+ if (ret)
+ dev_warn_ratelimited(dwc->dev,
+ "failed to init usb2 phy %d: %d\n",
+ i, ret);
+ }
+ }
+
for (i = 0; i < dwc->num_usb2_ports; i++)
phy_pm_runtime_get_sync(dwc->usb2_generic_phy[i]);
for (i = 0; i < dwc->num_usb3_ports; i++)diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index a35b3db1f9f3..f64cf709e194 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1403,6 +1403,7 @@ struct dwc3 {
unsigned dis_metastability_quirk:1;
unsigned dis_split_quirk:1;
+ unsigned reinit_phy_on_resume:1;
unsigned async_callbacks:1;
unsigned sys_wakeup:1;
unsigned wakeup_configured:1;--
2.53.0