[v4,2/2] usb: dwc3: core: Support the dwc3 host suspend/resume

Message ID 5e67c4a6680bbc7c02e92305d81eda5449b8a4af.1479991143.git.baolin.wang@linaro.org
State New
Headers show

Commit Message

Baolin Wang Nov. 28, 2016, 6:43 a.m.
For some mobile devices with strict power management, we also want to suspend
the host when the slave is detached for power saving. Thus we add the host
suspend/resume functions to support this requirement.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>

---
Changes since v3:
 - No updates.

Changes since v2:
 - Remove pm_children_suspended() and other unused macros.

 Changes since v1:
   - Add pm_runtime.h head file to avoid kbuild error.
---
 drivers/usb/dwc3/Kconfig |    7 +++++++
 drivers/usb/dwc3/core.c  |   26 +++++++++++++++++++++++++-
 drivers/usb/dwc3/core.h  |   15 +++++++++++++++
 drivers/usb/dwc3/host.c  |   37 +++++++++++++++++++++++++++++++++++++
 4 files changed, 84 insertions(+), 1 deletion(-)

-- 
1.7.9.5

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Comments

Baolin Wang Dec. 8, 2016, 11:14 a.m. | #1
Hi,

On 8 December 2016 at 19:02, Felipe Balbi <balbi@kernel.org> wrote:
>

> Hi,

>

> Baolin Wang <baolin.wang@linaro.org> writes:

>>>> On 28 November 2016 at 14:43, Baolin Wang <baolin.wang@linaro.org> wrote:

>>>>> For some mobile devices with strict power management, we also want to suspend

>>>>> the host when the slave is detached for power saving. Thus we add the host

>>>>> suspend/resume functions to support this requirement.

>>>>>

>>>>> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>

>>>>> ---

>>>>> Changes since v3:

>>>>>  - No updates.

>>>>>

>>>>> Changes since v2:

>>>>>  - Remove pm_children_suspended() and other unused macros.

>>>>>

>>>>>  Changes since v1:

>>>>>    - Add pm_runtime.h head file to avoid kbuild error.

>>>>> ---

>>>>>  drivers/usb/dwc3/Kconfig |    7 +++++++

>>>>>  drivers/usb/dwc3/core.c  |   26 +++++++++++++++++++++++++-

>>>>>  drivers/usb/dwc3/core.h  |   15 +++++++++++++++

>>>>>  drivers/usb/dwc3/host.c  |   37 +++++++++++++++++++++++++++++++++++++

>>>>>  4 files changed, 84 insertions(+), 1 deletion(-)

>>>>>

>>>>> diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig

>>>>> index a45b4f1..47bb2f3 100644

>>>>> --- a/drivers/usb/dwc3/Kconfig

>>>>> +++ b/drivers/usb/dwc3/Kconfig

>>>>> @@ -47,6 +47,13 @@ config USB_DWC3_DUAL_ROLE

>>>>>

>>>>>  endchoice

>>>>>

>>>>> +config USB_DWC3_HOST_SUSPEND

>>>>> +       bool "Choose if the DWC3 host (xhci) can be suspend/resume"

>>>>> +       depends on USB_DWC3_HOST=y || USB_DWC3_DUAL_ROLE=y

>>>

>>> why do you need another Kconfig for this? Just enable it already :-p

>>

>> I assume some platforms may do not need this feature. But okay, I can

>> remove this kconfig and enable it.

>

> thanks :-)

>

>>>>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c

>>>>> index 9a4a5e4..7ad4bc3 100644

>>>>> --- a/drivers/usb/dwc3/core.c

>>>>> +++ b/drivers/usb/dwc3/core.c

>>>>> @@ -1091,6 +1091,7 @@ static int dwc3_probe(struct platform_device *pdev)

>>>>>         pm_runtime_use_autosuspend(dev);

>>>>>         pm_runtime_set_autosuspend_delay(dev, DWC3_DEFAULT_AUTOSUSPEND_DELAY);

>>>>>         pm_runtime_enable(dev);

>>>>> +       pm_suspend_ignore_children(dev, true);

>>>

>>> why do you need this?

>>

>> Since the dwc3 device is the parent deive of xhci device, if we want

>> to suspend dwc3 device, we need to suspend child device (xhci device)

>> manually by issuing pm_runtime_put_sync() in dwc3_host_suspend(). In

>> pm_runtime_put_sync(), it will check if the children (xhci device) of

>> dwc3 device have been in suspend state, if not we will suspend dwc3

>> device failed.

>>

>> We get/put the child device manually in parent device's runtime

>> callback, we need to ignore the child device's runtime state, or it

>> will failed due to the dependency.

>

> I see. Good explanation :-)

>

> There's one thing though, if you want to runtime suspend the gadget and

> dwc3 is working on peripheral mode, host side (XHCI) should already be

> runtime suspended because there's nothing attached to it. Why isn't it

> runtime suspended?


Since we have get the runtime count for xHCI device in
xhci_plat_probe(), in case it will suspend automatically if some
controllers do not want xHCI enters runtime suspend automatically. So
the parent device (dwc3 device) need to get/put the xHCI device's
runtime count  to resume/suspend xHCI.

-- 
Baolin.wang
Best Regards
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Patch hide | download patch | download mbox

diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
index a45b4f1..47bb2f3 100644
--- a/drivers/usb/dwc3/Kconfig
+++ b/drivers/usb/dwc3/Kconfig
@@ -47,6 +47,13 @@  config USB_DWC3_DUAL_ROLE
 
 endchoice
 
+config USB_DWC3_HOST_SUSPEND
+	bool "Choose if the DWC3 host (xhci) can be suspend/resume"
+	depends on USB_DWC3_HOST=y || USB_DWC3_DUAL_ROLE=y
+	help
+	  We can suspend the host when the slave is detached for power saving,
+	  and resume the host when one slave is attached.
+
 comment "Platform Glue Driver Support"
 
 config USB_DWC3_OMAP
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 9a4a5e4..7ad4bc3 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1091,6 +1091,7 @@  static int dwc3_probe(struct platform_device *pdev)
 	pm_runtime_use_autosuspend(dev);
 	pm_runtime_set_autosuspend_delay(dev, DWC3_DEFAULT_AUTOSUSPEND_DELAY);
 	pm_runtime_enable(dev);
+	pm_suspend_ignore_children(dev, true);
 	ret = pm_runtime_get_sync(dev);
 	if (ret < 0)
 		goto err1;
@@ -1215,15 +1216,27 @@  static int dwc3_remove(struct platform_device *pdev)
 static int dwc3_suspend_common(struct dwc3 *dwc)
 {
 	unsigned long	flags;
+	int		ret;
 
 	switch (dwc->dr_mode) {
 	case USB_DR_MODE_PERIPHERAL:
+		spin_lock_irqsave(&dwc->lock, flags);
+		dwc3_gadget_suspend(dwc);
+		spin_unlock_irqrestore(&dwc->lock, flags);
+		break;
 	case USB_DR_MODE_OTG:
+		ret = dwc3_host_suspend(dwc);
+		if (ret)
+			return ret;
+
 		spin_lock_irqsave(&dwc->lock, flags);
 		dwc3_gadget_suspend(dwc);
 		spin_unlock_irqrestore(&dwc->lock, flags);
 		break;
 	case USB_DR_MODE_HOST:
+		ret = dwc3_host_suspend(dwc);
+		if (ret)
+			return ret;
 	default:
 		/* do nothing */
 		break;
@@ -1245,12 +1258,23 @@  static int dwc3_resume_common(struct dwc3 *dwc)
 
 	switch (dwc->dr_mode) {
 	case USB_DR_MODE_PERIPHERAL:
+		spin_lock_irqsave(&dwc->lock, flags);
+		dwc3_gadget_resume(dwc);
+		spin_unlock_irqrestore(&dwc->lock, flags);
+		break;
 	case USB_DR_MODE_OTG:
+		ret = dwc3_host_resume(dwc);
+		if (ret)
+			return ret;
+
 		spin_lock_irqsave(&dwc->lock, flags);
 		dwc3_gadget_resume(dwc);
 		spin_unlock_irqrestore(&dwc->lock, flags);
-		/* FALLTHROUGH */
+		break;
 	case USB_DR_MODE_HOST:
+		ret = dwc3_host_resume(dwc);
+		if (ret)
+			return ret;
 	default:
 		/* do nothing */
 		break;
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index b585a30..db41908 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1226,4 +1226,19 @@  static inline void dwc3_ulpi_exit(struct dwc3 *dwc)
 { }
 #endif
 
+#if IS_ENABLED(CONFIG_USB_DWC3_HOST_SUSPEND)
+int dwc3_host_suspend(struct dwc3 *dwc);
+int dwc3_host_resume(struct dwc3 *dwc);
+#else
+static inline int dwc3_host_suspend(struct dwc3 *dwc)
+{
+	return 0;
+}
+
+static inline int dwc3_host_resume(struct dwc3 *dwc)
+{
+	return 0;
+}
+#endif
+
 #endif /* __DRIVERS_USB_DWC3_CORE_H */
diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
index ed82464..8e5309d6 100644
--- a/drivers/usb/dwc3/host.c
+++ b/drivers/usb/dwc3/host.c
@@ -16,6 +16,7 @@ 
  */
 
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 
 #include "core.h"
 
@@ -130,3 +131,39 @@  void dwc3_host_exit(struct dwc3 *dwc)
 			  dev_name(&dwc->xhci->dev));
 	platform_device_unregister(dwc->xhci);
 }
+
+#ifdef CONFIG_USB_DWC3_HOST_SUSPEND
+int dwc3_host_suspend(struct dwc3 *dwc)
+{
+	struct device *xhci = &dwc->xhci->dev;
+	int ret;
+
+	/*
+	 * Note: if we get the -EBUSY, which means the xHCI children devices are
+	 * not in suspend state yet, the glue layer need to wait for a while and
+	 * try to suspend xHCI device again.
+	 */
+	ret = pm_runtime_put_sync(xhci);
+	if (ret) {
+		dev_err(xhci, "failed to suspend xHCI device\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+int dwc3_host_resume(struct dwc3 *dwc)
+{
+	struct device *xhci = &dwc->xhci->dev;
+	int ret;
+
+	/* Resume the xHCI device synchronously. */
+	ret = pm_runtime_get_sync(xhci);
+	if (ret) {
+		dev_err(xhci, "failed to resume xHCI device\n");
+		return ret;
+	}
+
+	return 0;
+}
+#endif