Sharing a USB controller with another entity via xhci-sideband driver
creates power management complexities. To prevent the USB controller
from being inadvertently deactivated while in use by the other entity, a
usage-count based mechanism is implemented. This allows the system to
manage power effectively, ensuring the controller remains available
whenever needed.
Signed-off-by: Guan-Yu Lin <guanyulin@xxxxxxxxxx>
---
drivers/usb/core/driver.c | 10 ++++++++++
drivers/usb/core/hcd.c | 1 +
drivers/usb/core/usb.c | 1 +
drivers/usb/dwc3/core.c | 13 +++++++++++++
drivers/usb/dwc3/core.h | 8 ++++++++
drivers/usb/host/xhci-plat.c | 10 ++++++++++
drivers/usb/host/xhci-plat.h | 7 +++++++
sound/usb/qcom/qc_audio_offload.c | 3 +++
8 files changed, 53 insertions(+)
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index e713cf9b3dd2..eb85cbb1a2ff 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -1583,6 +1583,11 @@ int usb_suspend(struct device *dev, pm_message_t msg)
struct usb_device *udev = to_usb_device(dev);
int r;
+ if (msg.event == PM_EVENT_SUSPEND && usb_sideband_check(udev)) {
+ dev_dbg(dev, "device accessed via sideband\n");
+ return 0;
+ }
+
unbind_no_pm_drivers_interfaces(udev);
/* From now on we are sure all drivers support suspend/resume
@@ -1619,6 +1624,11 @@ int usb_resume(struct device *dev, pm_message_t msg)
struct usb_device *udev = to_usb_device(dev);
int status;
+ if (msg.event == PM_EVENT_RESUME && usb_sideband_check(udev)) {
+ dev_dbg(dev, "device accessed via sideband\n");
+ return 0;
+ }
+
/* For all calls, take the device back to full power and
* tell the PM core in case it was autosuspended previously.
* Unbind the interfaces that will need rebinding later,
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 1ff7d901fede..9876b3940281 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2593,6 +2593,7 @@ struct usb_hcd *__usb_create_hcd(const struct hc_driver *driver,
timer_setup(&hcd->rh_timer, rh_timer_func, 0);
#ifdef CONFIG_PM
INIT_WORK(&hcd->wakeup_work, hcd_resume_work);
+ refcount_set(&hcd->sb_usage_count, 0);
#endif
INIT_WORK(&hcd->died_work, hcd_died_work);
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index 0b4685aad2d5..d315d066a56b 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -671,6 +671,7 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent,
dev->state = USB_STATE_ATTACHED;
dev->lpm_disable_count = 1;
atomic_set(&dev->urbnum, 0);
+ refcount_set(&dev->sb_usage_count, 0);
INIT_LIST_HEAD(&dev->ep0.urb_list);
dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 2fdafbcbe44c..18c743ce5ac5 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -2550,8 +2550,15 @@ static int dwc3_runtime_idle(struct device *dev)
static int dwc3_suspend(struct device *dev)
{
struct dwc3 *dwc = dev_get_drvdata(dev);
+ struct platform_device *xhci = dwc->xhci;
int ret;
+ if (xhci && xhci_sideband_check(xhci->dev.driver_data)) {
+ dev_dbg(dev, "device accessed via sideband\n");
+ return 0;
+ }
+
+
ret = dwc3_suspend_common(dwc, PMSG_SUSPEND);
if (ret)
return ret;
@@ -2564,8 +2571,14 @@ static int dwc3_suspend(struct device *dev)
static int dwc3_resume(struct device *dev)
{
struct dwc3 *dwc = dev_get_drvdata(dev);
+ struct platform_device *xhci = dwc->xhci;
int ret;
+ if (xhci && xhci_sideband_check(xhci->dev.driver_data)) {
+ dev_dbg(dev, "device accessed via sideband\n");
+ return 0;
+ }
+
pinctrl_pm_select_default_state(dev);
pm_runtime_disable(dev);
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 80047d0df179..e06d597ee3b0 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -26,6 +26,7 @@
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>
#include <linux/usb/otg.h>
+#include <linux/usb/hcd.h>
#include <linux/usb/role.h>
#include <linux/ulpi/interface.h>
@@ -1704,4 +1705,11 @@ static inline void dwc3_ulpi_exit(struct dwc3 *dwc)
{ }
#endif
+#if IS_ENABLED(CONFIG_USB_XHCI_SIDEBAND)
+extern bool xhci_sideband_check(struct usb_hcd *hcd);
+#else
+static inline bool xhci_sideband_check(struct usb_hcd *hcd)
+{ return false; }
+#endif
+
#endif /* __DRIVERS_USB_DWC3_CORE_H */
diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index 6e49ef1908eb..5fdbdf0c7f1a 100644
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -456,6 +456,11 @@ static int xhci_plat_suspend_common(struct device *dev, struct pm_message pmsg)
struct xhci_hcd *xhci = hcd_to_xhci(hcd);
int ret;
+ if (pmsg.event == PM_EVENT_SUSPEND && xhci_sideband_check(hcd)) {
+ dev_dbg(dev, "device accessed via sideband\n");
+ return 0;
+ }
+
if (pm_runtime_suspended(dev))
pm_runtime_resume(dev);
@@ -499,6 +504,11 @@ static int xhci_plat_resume_common(struct device *dev, struct pm_message pmsg)
struct xhci_hcd *xhci = hcd_to_xhci(hcd);
int ret;
+ if (pmsg.event == PM_EVENT_RESUME && xhci_sideband_check(hcd)) {
+ dev_dbg(dev, "device accessed via sideband\n");
+ return 0;
+ }
+
if (!device_may_wakeup(dev) && (xhci->quirks & XHCI_SUSPEND_RESUME_CLKS)) {
ret = clk_prepare_enable(xhci->clk);
if (ret)
diff --git a/drivers/usb/host/xhci-plat.h b/drivers/usb/host/xhci-plat.h
index 6475130eac4b..432a040c81e5 100644
--- a/drivers/usb/host/xhci-plat.h
+++ b/drivers/usb/host/xhci-plat.h
@@ -30,4 +30,11 @@ int xhci_plat_probe(struct platform_device *pdev, struct device *sysdev,
void xhci_plat_remove(struct platform_device *dev);
extern const struct dev_pm_ops xhci_plat_pm_ops;
+#if IS_ENABLED(CONFIG_USB_XHCI_SIDEBAND)
+extern bool xhci_sideband_check(struct usb_hcd *hcd);
+#else
+static inline bool xhci_sideband_check(struct usb_hcd *hcd)
+{ return false; }
+#endif
+
#endif /* _XHCI_PLAT_H */
diff --git a/sound/usb/qcom/qc_audio_offload.c b/sound/usb/qcom/qc_audio_offload.c
index 2dc651cd3d05..c82b5dbef2d7 100644
--- a/sound/usb/qcom/qc_audio_offload.c
+++ b/sound/usb/qcom/qc_audio_offload.c
@@ -1516,8 +1516,11 @@ static void handle_uaudio_stream_req(struct qmi_handle *handle,
mutex_lock(&chip->mutex);
subs->opened = 0;
mutex_unlock(&chip->mutex);
+ } else {
+ xhci_sideband_get(uadev[pcm_card_num].sb);
}
} else {
+ xhci_sideband_put(uadev[pcm_card_num].sb);
info = &uadev[pcm_card_num].info[info_idx];
if (info->data_ep_pipe) {
ep = usb_pipe_endpoint(uadev[pcm_card_num].udev,
--
2.47.0.rc1.288.g06298d1525-goog
