On Qualcomm DWC3 dual-role controllers, the conndone/disconnect events in
device mode are generated by controller when software writes to QSCRATCH
registers in Qualcomm Glue layer rather than the vbus line being routed to
dwc3 core IP for it to recognize and generate these events.
UTMI_OTG_VBUS_VALID bit of QSCRATCH_HS_PHY_CTRL register needs to be set
to generate a connection done event and to be cleared for the controller to
generate a disconnect event during cable removal. When the disconnect is
not generated upon cable removal, the "connected" flag of dwc3 is left
marked as "true" and it blocks suspend routines and for that to happen upon
cable removal, the cable disconnect notification coming in via set_role
call need to be provided to the Qualcomm glue layer as well.
Currently, the way DWC3 core and Qualcomm legacy glue driver are designed,
there is no mechanism through which the DWC3 core can notify the Qualcomm
glue layer of any role changes which it receives via role switch. To
register these glue callbacks at probe time, for enabling core to notify
glue layer, the legacy Qualcomm driver has no way to find out when the
child driver probe was successful since it does not check for the same
during of_platform_populate.
Hence implement the following glue callbacks for flattened Qualcomm glue
driver:
1. set_role: To pass role switching information from drd layer to glue.
This information is needed to identify NONE/DEVICE mode switch and modify
QSCRATCH to generate connect-done event on device mode entry and disconnect
event on cable removal in device mode.
2. run_stop: When booting up in device mode, if autouspend is enabled and
userspace doesn't write UDC on boot, controller enters autosuspend. After
this, if the userspace writes to UDC in the future, run_stop notifier is
required to enable UTMI_OTG_VBUS_VALID of QSCRATCH so that connect done
event is generated after run_stop(1) is done to finish enumeration.
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Krishna Kurapati <krishna.kurapati@oss.qualcomm.com>
---
drivers/usb/dwc3/dwc3-qcom.c | 78 +++++++++++++++++++++++++++++++-----
1 file changed, 68 insertions(+), 10 deletions(-)
diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
index 8a9018ca650c..ded2ca86670c 100644
--- a/drivers/usb/dwc3/dwc3-qcom.c
+++ b/drivers/usb/dwc3/dwc3-qcom.c
@@ -83,6 +83,8 @@ struct dwc3_qcom {
bool pm_suspended;
struct icc_path *icc_path_ddr;
struct icc_path *icc_path_apps;
+
+ enum usb_role current_role;
};
#define to_dwc3_qcom(d) container_of((d), struct dwc3_qcom, dwc)
@@ -111,10 +113,6 @@ static inline void dwc3_qcom_clrbits(void __iomem *base, u32 offset, u32 val)
readl(base + offset);
}
-/*
- * TODO: Make the in-core role switching code invoke dwc3_qcom_vbus_override_enable(),
- * validate that the in-core extcon support is functional
- */
static void dwc3_qcom_vbus_override_enable(struct dwc3_qcom *qcom, bool enable)
{
if (enable) {
@@ -560,6 +558,55 @@ static int dwc3_qcom_setup_irq(struct dwc3_qcom *qcom, struct platform_device *p
return 0;
}
+static void dwc3_qcom_set_role_notifier(struct dwc3 *dwc, enum usb_role next_role)
+{
+ struct dwc3_qcom *qcom = to_dwc3_qcom(dwc);
+
+ if (qcom->current_role == next_role)
+ return;
+
+ if (pm_runtime_resume_and_get(qcom->dev)) {
+ dev_dbg(qcom->dev, "Failed to resume device\n");
+ return;
+ }
+
+ if (qcom->current_role == USB_ROLE_DEVICE)
+ dwc3_qcom_vbus_override_enable(qcom, false);
+ else if (qcom->current_role != USB_ROLE_DEVICE)
+ dwc3_qcom_vbus_override_enable(qcom, true);
+
+ pm_runtime_mark_last_busy(qcom->dev);
+ pm_runtime_put_sync(qcom->dev);
+
+ /*
+ * Current role changes via usb_role_switch_set_role callback protected
+ * internally by mutex lock.
+ */
+ qcom->current_role = next_role;
+}
+
+static void dwc3_qcom_run_stop_notifier(struct dwc3 *dwc, bool is_on)
+{
+ struct dwc3_qcom *qcom = to_dwc3_qcom(dwc);
+
+ /*
+ * When autosuspend is enabled and controller goes to suspend
+ * after removing UDC from userspace, the next UDC write needs
+ * setting of QSCRATCH VBUS_VALID to "1" to generate a connect
+ * done event.
+ */
+ if (!is_on)
+ return;
+
+ dwc3_qcom_vbus_override_enable(qcom, true);
+ pm_runtime_mark_last_busy(qcom->dev);
+}
+
+struct dwc3_glue_ops dwc3_qcom_glue_ops = {
+ .pre_set_role = dwc3_qcom_set_role_notifier,
+ .pre_run_stop = dwc3_qcom_run_stop_notifier,
+};
+
static int dwc3_qcom_probe(struct platform_device *pdev)
{
struct dwc3_probe_data probe_data = {};
@@ -636,6 +683,23 @@ static int dwc3_qcom_probe(struct platform_device *pdev)
if (ignore_pipe_clk)
dwc3_qcom_select_utmi_clk(qcom);
+ qcom->mode = usb_get_dr_mode(dev);
+
+ if (qcom->mode == USB_DR_MODE_HOST) {
+ qcom->current_role = USB_ROLE_HOST;
+ } else if (qcom->mode == USB_DR_MODE_PERIPHERAL) {
+ qcom->current_role = USB_ROLE_DEVICE;
+ dwc3_qcom_vbus_override_enable(qcom, true);
+ } else {
+ if ((device_property_read_bool(dev, "usb-role-switch")) &&
+ (usb_get_role_switch_default_mode(dev) == USB_DR_MODE_HOST))
+ qcom->current_role = USB_ROLE_HOST;
+ else
+ qcom->current_role = USB_ROLE_DEVICE;
+ }
+
+ qcom->dwc.glue_ops = &dwc3_qcom_glue_ops;
+
qcom->dwc.dev = dev;
probe_data.dwc = &qcom->dwc;
probe_data.res = &res;
@@ -650,12 +714,6 @@ static int dwc3_qcom_probe(struct platform_device *pdev)
if (ret)
goto remove_core;
- qcom->mode = usb_get_dr_mode(dev);
-
- /* enable vbus override for device mode */
- if (qcom->mode != USB_DR_MODE_HOST)
- dwc3_qcom_vbus_override_enable(qcom, true);
-
wakeup_source = of_property_read_bool(dev->of_node, "wakeup-source");
device_init_wakeup(&pdev->dev, wakeup_source);
--
2.34.1Hi Krishna,
kernel test robot noticed the following build warnings:
[auto build test WARNING on usb/usb-testing]
[also build test WARNING on usb/usb-next next-20250908]
[cannot apply to usb/usb-linus linus/master v6.17-rc5]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Krishna-Kurapati/usb-dwc3-core-Introduce-glue-callbacks-for-flattened-implementations/20250908-021710
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
patch link: https://lore.kernel.org/r/20250907181412.2174616-3-krishna.kurapati%40oss.qualcomm.com
patch subject: [PATCH v5 2/2] usb: dwc3: qcom: Implement glue callbacks to facilitate runtime suspend
config: hexagon-randconfig-r132-20250908 (https://download.01.org/0day-ci/archive/20250909/202509090115.dVhd78BE-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce: (https://download.01.org/0day-ci/archive/20250909/202509090115.dVhd78BE-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202509090115.dVhd78BE-lkp@intel.com/
sparse warnings: (new ones prefixed by >>)
>> drivers/usb/dwc3/dwc3-qcom.c:605:22: sparse: sparse: symbol 'dwc3_qcom_glue_ops' was not declared. Should it be static?
vim +/dwc3_qcom_glue_ops +605 drivers/usb/dwc3/dwc3-qcom.c
604
> 605 struct dwc3_glue_ops dwc3_qcom_glue_ops = {
606 .pre_set_role = dwc3_qcom_set_role_notifier,
607 .pre_run_stop = dwc3_qcom_run_stop_notifier,
608 };
609
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
On 9/8/2025 11:55 PM, kernel test robot wrote:
> Hi Krishna,
>
> kernel test robot noticed the following build warnings:
>
> [auto build test WARNING on usb/usb-testing]
> [also build test WARNING on usb/usb-next next-20250908]
> [cannot apply to usb/usb-linus linus/master v6.17-rc5]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
>
> url: https://github.com/intel-lab-lkp/linux/commits/Krishna-Kurapati/usb-dwc3-core-Introduce-glue-callbacks-for-flattened-implementations/20250908-021710
> base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
> patch link: https://lore.kernel.org/r/20250907181412.2174616-3-krishna.kurapati%40oss.qualcomm.com
> patch subject: [PATCH v5 2/2] usb: dwc3: qcom: Implement glue callbacks to facilitate runtime suspend
> config: hexagon-randconfig-r132-20250908 (https://download.01.org/0day-ci/archive/20250909/202509090115.dVhd78BE-lkp@intel.com/config)
> compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
> reproduce: (https://download.01.org/0day-ci/archive/20250909/202509090115.dVhd78BE-lkp@intel.com/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202509090115.dVhd78BE-lkp@intel.com/
>
> sparse warnings: (new ones prefixed by >>)
>>> drivers/usb/dwc3/dwc3-qcom.c:605:22: sparse: sparse: symbol 'dwc3_qcom_glue_ops' was not declared. Should it be static?
>
> vim +/dwc3_qcom_glue_ops +605 drivers/usb/dwc3/dwc3-qcom.c
>
> 604
> > 605 struct dwc3_glue_ops dwc3_qcom_glue_ops = {
> 606 .pre_set_role = dwc3_qcom_set_role_notifier,
> 607 .pre_run_stop = dwc3_qcom_run_stop_notifier,
> 608 };
> 609
>
I see that the usb-linus is missing the following patch:
https://lore.kernel.org/all/20250729092708.3628187-1-krishna.kurapati@oss.qualcomm.com/
Regards,
Krishna,
© 2016 - 2025 Red Hat, Inc.