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[v15,0/6] USB DWC3 host wake up support from system suspend

Message ID 1651740973-7944-1-git-send-email-quic_kriskura@quicinc.com
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Series USB DWC3 host wake up support from system suspend | expand

Message

Krishna Kurapati May 5, 2022, 8:56 a.m. UTC 
Avoiding phy powerdown in host mode when wakeup capable devices are 
connected, so that it can be wake up by devices.
Keep usb30_prim gdsc active to retain controller status
during suspend/resume.

Changes in v15:
Added patch to enable wakeup for xhci-plat based on children wakeup status.
Used device_wakeup_path instead of device_children_wakeup_capable

Changes in v14:
Added patch for device_children_wakeup_capable.
Used device_children_wakeup_capable instead of usb_wakeup_enabled_descendants.
Fixed minor nit picks in v13 reported by Matthias.

Changes in v13:
Moved the dt bindings patch to start.
Changed dwc3_set_phy_speed_mode to dwc3_check_phy_speed_mode.
Check wakep-source property for dwc3 core node to set the
wakeup capability. Drop the device_init_wakeup call from
runtime suspend and resume.
Added GENPD_FLAG_RPM_ALWAYS_ON and set GENPD_FLAG_ALWAYS_ON if
wakeup is supported.

Changes in v12:
Squashed PATCH 1/5 and 2/5 of v11.
Added dt bindings and device tree entry for wakeup-source property
for dwc3 core node.
Dropped redundant phy_set_mode call.


Changes in v11:
Moving back to v8 version
https://patchwork.kernel.org/project/linux-arm-msm/cover/1624882097-23265-1-git-send-email-sanm@codeaurora.org
as we are getting interrupts during suspend
when enabling both DP hs phy irq and DM hs phy irq.
Moved the set phy mode function to dwc3/core.c from xhci-plat.c
We didn't find any other option other than accessing xhci from dwc.

Changes in v10:
PATCH 1/6: Change device_set_wakeup_capable to device_set_wakeup_enable
PATCH 2/6: Remove redundant else part in dwc3_resume_common
PATCH 4/6: Change the irg flags
PATCH 5/6: Set flag GENPD_FLAG_ALWAYS_ON
PATCH 6/6: Remove disable interrupts function and enable
interrupts in probe.


Changes in v9:
Checking with device_may_makeup property instead of phy_power_off flag.
Changed the IRQ flags and removed hs_phy_mode variable.

Changes in v8:
Moved the dwc3 suspend quirk code in dwc3/host.c to xhci-plat.c
Checking phy_power_off flag instead of usb_wakeup_enabled_descendants 
to keep gdsc active.

Changes in v7:
Change in commit text and message in PATCH 1/5 and PATCH 5/5
as per Matthias suggestion.
Added curly braces for if and else if sections in PATCH 4/5.

Changes in v6:
Addressed comments in host.c and core.c
Separated the patches in dwc3-qcom.c to make it simple.
Dropped wakeup-source change as it is not related to this series.

Changes in v5:
Added phy_power_off flag to check presence of wakeup capable devices.
Dropped patch[v4,4/5] as it is present linux-next.
Addressed comments in host.c and dwc3-qcom.c.

Changes in v4:
Addressed Matthias comments raised in v3.

Changes in v3:
Removed need_phy_for_wakeup flag and by default avoiding phy powerdown.
Addressed Matthias comments and added entry for DEV_SUPERSPEED.
Added suspend_quirk in dwc3 host and moved the dwc3_set_phy_speed_flags.
Added wakeup-source dt entry and reading in dwc-qcom.c glue driver.

Changes in v2:
Dropped the patch in clock to set GENPD_FLAG_ACTIVE_WAKEUP flag and 
setting in usb dwc3 driver.
Separated the core patch and glue driver patch.
Made need_phy_for_wakeup flag part of dwc structure and 
hs_phy_flags as unsgined int.
Adrressed the comment on device_init_wakeup call.
Corrected offset for reading portsc register.
Added pacth to support wakeup in xo shutdown case.

Krishna Kurapati (1):
  usb: host: xhci-plat: Enable wakeup based on children wakeup status

Sandeep Maheswaram (5):
  dt-bindings: usb: dwc3: Add wakeup-source property support
  usb: dwc3: core: Host wake up support from system suspend
  usb: dwc3: qcom: Add helper functions to enable,disable wake irqs
  usb: dwc3: qcom: Configure wakeup interrupts during suspend
  usb: dwc3: qcom: Keep power domain on to retain controller status

 .../devicetree/bindings/usb/snps,dwc3.yaml         |  5 ++
 drivers/usb/dwc3/core.c                            | 33 ++++----
 drivers/usb/dwc3/core.h                            |  4 +
 drivers/usb/dwc3/dwc3-qcom.c                       | 91 +++++++++++++---------
 drivers/usb/dwc3/host.c                            | 24 ++++++
 drivers/usb/host/xhci-plat.c                       |  8 ++
 6 files changed, 115 insertions(+), 50 deletions(-)

Comments

Matthias Kaehlcke May 5, 2022, 10:48 p.m. UTC | #1 
On Thu, May 05, 2022 at 02:26:10PM +0530, Krishna Kurapati wrote:
> From: Sandeep Maheswaram <quic_c_sanm@quicinc.com>
> 
> During suspend read the status of all port and set hs phy mode
> based on current speed. Use this hs phy mode to configure wakeup
> interrupts in qcom glue driver.
> 
> Check wakeup-source property for dwc3 core node to set the
> wakeup capability. Drop the device_init_wakeup call from
> runtime suspend and resume.
> 
> Also check during suspend if any wakeup capable devices are
> connected to the controller (directly or through hubs), if there
> are none set a flag to indicate that the PHY is powered
> down during suspend.
> 
> Signed-off-by: Sandeep Maheswaram <quic_c_sanm@quicinc.com>
> Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
> ---
>  drivers/usb/dwc3/core.c | 33 ++++++++++++++++++++-------------
>  drivers/usb/dwc3/core.h |  4 ++++
>  drivers/usb/dwc3/host.c | 24 ++++++++++++++++++++++++
>  3 files changed, 48 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 950e238..cf377f5 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -33,6 +33,7 @@
>  #include <linux/usb/gadget.h>
>  #include <linux/usb/of.h>
>  #include <linux/usb/otg.h>
> +#include <linux/usb/hcd.h>

This is not needed anymore

>  
>  #include "core.h"
>  #include "gadget.h"
> @@ -1787,6 +1788,7 @@ static int dwc3_probe(struct platform_device *pdev)
>  
>  	platform_set_drvdata(pdev, dwc);
>  	dwc3_cache_hwparams(dwc);
> +	device_init_wakeup(&pdev->dev, of_property_read_bool(dev->of_node, "wakeup-source"));
>  
>  	spin_lock_init(&dwc->lock);
>  	mutex_init(&dwc->mutex);
> @@ -1936,6 +1938,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
>  {
>  	unsigned long	flags;
>  	u32 reg;
> +	struct usb_hcd  *hcd = platform_get_drvdata(dwc->xhci);

This isn't used anymore, delete it

>  
>  	switch (dwc->current_dr_role) {
>  	case DWC3_GCTL_PRTCAP_DEVICE:
> @@ -1948,10 +1951,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
>  		dwc3_core_exit(dwc);
>  		break;
>  	case DWC3_GCTL_PRTCAP_HOST:
> -		if (!PMSG_IS_AUTO(msg)) {
> -			dwc3_core_exit(dwc);
> -			break;
> -		}
> +		dwc3_check_phy_speed_mode(dwc);
>  
>  		/* Let controller to suspend HSPHY before PHY driver suspends */
>  		if (dwc->dis_u2_susphy_quirk ||
> @@ -1967,6 +1967,16 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
>  
>  		phy_pm_runtime_put_sync(dwc->usb2_generic_phy);
>  		phy_pm_runtime_put_sync(dwc->usb3_generic_phy);
> +
> +		if (!PMSG_IS_AUTO(msg)) {
> +			if (device_may_wakeup(dwc->dev) &&
> +					device_wakeup_path(dwc->dev)) {

nit: the indentation is odd, align it with device_may_wakeup()?

> +				dwc->phy_power_off = false;
> +			} else {
> +				dwc->phy_power_off = true;
> +				dwc3_core_exit(dwc);

As commented earlier, taking the controller and PHYs completely down causes a
significant power draw in some USB clients. Let's clarify what the specific
benefits are of doing dwc3_core_exit() vs. entering a low power mode.
Krishna Kurapati May 6, 2022, 5:11 a.m. UTC | #2 
On 5/6/2022 4:18 AM, Matthias Kaehlcke wrote:
> On Thu, May 05, 2022 at 02:26:10PM +0530, Krishna Kurapati wrote:
>> From: Sandeep Maheswaram <quic_c_sanm@quicinc.com>
>>
>> During suspend read the status of all port and set hs phy mode
>> based on current speed. Use this hs phy mode to configure wakeup
>> interrupts in qcom glue driver.
>>
>> Check wakeup-source property for dwc3 core node to set the
>> wakeup capability. Drop the device_init_wakeup call from
>> runtime suspend and resume.
>>
>> Also check during suspend if any wakeup capable devices are
>> connected to the controller (directly or through hubs), if there
>> are none set a flag to indicate that the PHY is powered
>> down during suspend.
>>
>> Signed-off-by: Sandeep Maheswaram <quic_c_sanm@quicinc.com>
>> Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
>> ---
>>   drivers/usb/dwc3/core.c | 33 ++++++++++++++++++++-------------
>>   drivers/usb/dwc3/core.h |  4 ++++
>>   drivers/usb/dwc3/host.c | 24 ++++++++++++++++++++++++
>>   3 files changed, 48 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>> index 950e238..cf377f5 100644
>> --- a/drivers/usb/dwc3/core.c
>> +++ b/drivers/usb/dwc3/core.c
>> @@ -33,6 +33,7 @@
>>   #include <linux/usb/gadget.h>
>>   #include <linux/usb/of.h>
>>   #include <linux/usb/otg.h>
>> +#include <linux/usb/hcd.h>
> This is not needed anymore
>
>>   
>>   #include "core.h"
>>   #include "gadget.h"
>> @@ -1787,6 +1788,7 @@ static int dwc3_probe(struct platform_device *pdev)
>>   
>>   	platform_set_drvdata(pdev, dwc);
>>   	dwc3_cache_hwparams(dwc);
>> +	device_init_wakeup(&pdev->dev, of_property_read_bool(dev->of_node, "wakeup-source"));
>>   
>>   	spin_lock_init(&dwc->lock);
>>   	mutex_init(&dwc->mutex);
>> @@ -1936,6 +1938,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
>>   {
>>   	unsigned long	flags;
>>   	u32 reg;
>> +	struct usb_hcd  *hcd = platform_get_drvdata(dwc->xhci);
> This isn't used anymore, delete it
My bad, Will fix this in next version.
>>   
>>   	switch (dwc->current_dr_role) {
>>   	case DWC3_GCTL_PRTCAP_DEVICE:
>> @@ -1948,10 +1951,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
>>   		dwc3_core_exit(dwc);
>>   		break;
>>   	case DWC3_GCTL_PRTCAP_HOST:
>> -		if (!PMSG_IS_AUTO(msg)) {
>> -			dwc3_core_exit(dwc);
>> -			break;
>> -		}
>> +		dwc3_check_phy_speed_mode(dwc);
>>   
>>   		/* Let controller to suspend HSPHY before PHY driver suspends */
>>   		if (dwc->dis_u2_susphy_quirk ||
>> @@ -1967,6 +1967,16 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
>>   
>>   		phy_pm_runtime_put_sync(dwc->usb2_generic_phy);
>>   		phy_pm_runtime_put_sync(dwc->usb3_generic_phy);
>> +
>> +		if (!PMSG_IS_AUTO(msg)) {
>> +			if (device_may_wakeup(dwc->dev) &&
>> +					device_wakeup_path(dwc->dev)) {
> nit: the indentation is odd, align it with device_may_wakeup()?
Sure, Will take care of it.
>> +				dwc->phy_power_off = false;
>> +			} else {
>> +				dwc->phy_power_off = true;
>> +				dwc3_core_exit(dwc);
> As commented earlier, taking the controller and PHYs completely down causes a
> significant power draw in some USB clients. Let's clarify what the specific
> benefits are of doing dwc3_core_exit() vs. entering a low power mode.
Sure, once we come to a conclusion on this, I will refresh the patches.
Pavan Kondeti May 6, 2022, 5:14 a.m. UTC | #3 
On Fri, May 06, 2022 at 10:41:01AM +0530, Krishna Kurapati PSSNV wrote:
> 
> On 5/6/2022 4:18 AM, Matthias Kaehlcke wrote:
> >On Thu, May 05, 2022 at 02:26:10PM +0530, Krishna Kurapati wrote:
> >>From: Sandeep Maheswaram <quic_c_sanm@quicinc.com>
> >>
> >>During suspend read the status of all port and set hs phy mode
> >>based on current speed. Use this hs phy mode to configure wakeup
> >>interrupts in qcom glue driver.
> >>
> >>Check wakeup-source property for dwc3 core node to set the
> >>wakeup capability. Drop the device_init_wakeup call from
> >>runtime suspend and resume.
> >>
> >>Also check during suspend if any wakeup capable devices are
> >>connected to the controller (directly or through hubs), if there
> >>are none set a flag to indicate that the PHY is powered
> >>down during suspend.
> >>
> >>Signed-off-by: Sandeep Maheswaram <quic_c_sanm@quicinc.com>
> >>Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
> >>---
> >>  drivers/usb/dwc3/core.c | 33 ++++++++++++++++++++-------------
> >>  drivers/usb/dwc3/core.h |  4 ++++
> >>  drivers/usb/dwc3/host.c | 24 ++++++++++++++++++++++++
> >>  3 files changed, 48 insertions(+), 13 deletions(-)
> >>
> >>diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> >>index 950e238..cf377f5 100644
> >>--- a/drivers/usb/dwc3/core.c
> >>+++ b/drivers/usb/dwc3/core.c
> >>@@ -33,6 +33,7 @@
> >>  #include <linux/usb/gadget.h>
> >>  #include <linux/usb/of.h>
> >>  #include <linux/usb/otg.h>
> >>+#include <linux/usb/hcd.h>
> >This is not needed anymore
> >
> >>  #include "core.h"
> >>  #include "gadget.h"
> >>@@ -1787,6 +1788,7 @@ static int dwc3_probe(struct platform_device *pdev)
> >>  	platform_set_drvdata(pdev, dwc);
> >>  	dwc3_cache_hwparams(dwc);
> >>+	device_init_wakeup(&pdev->dev, of_property_read_bool(dev->of_node, "wakeup-source"));
> >>  	spin_lock_init(&dwc->lock);
> >>  	mutex_init(&dwc->mutex);
> >>@@ -1936,6 +1938,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
> >>  {
> >>  	unsigned long	flags;
> >>  	u32 reg;
> >>+	struct usb_hcd  *hcd = platform_get_drvdata(dwc->xhci);
> >This isn't used anymore, delete it
> My bad, Will fix this in next version.
> >>  	switch (dwc->current_dr_role) {
> >>  	case DWC3_GCTL_PRTCAP_DEVICE:
> >>@@ -1948,10 +1951,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
> >>  		dwc3_core_exit(dwc);
> >>  		break;
> >>  	case DWC3_GCTL_PRTCAP_HOST:
> >>-		if (!PMSG_IS_AUTO(msg)) {
> >>-			dwc3_core_exit(dwc);
> >>-			break;
> >>-		}
> >>+		dwc3_check_phy_speed_mode(dwc);
> >>  		/* Let controller to suspend HSPHY before PHY driver suspends */
> >>  		if (dwc->dis_u2_susphy_quirk ||
> >>@@ -1967,6 +1967,16 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
> >>  		phy_pm_runtime_put_sync(dwc->usb2_generic_phy);
> >>  		phy_pm_runtime_put_sync(dwc->usb3_generic_phy);
> >>+
> >>+		if (!PMSG_IS_AUTO(msg)) {
> >>+			if (device_may_wakeup(dwc->dev) &&
> >>+					device_wakeup_path(dwc->dev)) {
> >nit: the indentation is odd, align it with device_may_wakeup()?
> Sure, Will take care of it.
> >>+				dwc->phy_power_off = false;
> >>+			} else {
> >>+				dwc->phy_power_off = true;
> >>+				dwc3_core_exit(dwc);
> >As commented earlier, taking the controller and PHYs completely down causes a
> >significant power draw in some USB clients. Let's clarify what the specific
> >benefits are of doing dwc3_core_exit() vs. entering a low power mode.
> Sure, once we come to a conclusion on this, I will refresh the patches.

I think, Matthias is asking you to clarify in the commit description. we can
even quote Matthias observations.

Thanks,
Pavan
Matthias Kaehlcke May 6, 2022, 3:51 p.m. UTC | #4 
On Fri, May 06, 2022 at 10:44:48AM +0530, Pavan Kondeti wrote:
> On Fri, May 06, 2022 at 10:41:01AM +0530, Krishna Kurapati PSSNV wrote:
> > 
> > On 5/6/2022 4:18 AM, Matthias Kaehlcke wrote:
> > >On Thu, May 05, 2022 at 02:26:10PM +0530, Krishna Kurapati wrote:
> > >>From: Sandeep Maheswaram <quic_c_sanm@quicinc.com>
> > >>
> > >>During suspend read the status of all port and set hs phy mode
> > >>based on current speed. Use this hs phy mode to configure wakeup
> > >>interrupts in qcom glue driver.
> > >>
> > >>Check wakeup-source property for dwc3 core node to set the
> > >>wakeup capability. Drop the device_init_wakeup call from
> > >>runtime suspend and resume.
> > >>
> > >>Also check during suspend if any wakeup capable devices are
> > >>connected to the controller (directly or through hubs), if there
> > >>are none set a flag to indicate that the PHY is powered
> > >>down during suspend.
> > >>
> > >>Signed-off-by: Sandeep Maheswaram <quic_c_sanm@quicinc.com>
> > >>Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
> > >>---
> > >>  drivers/usb/dwc3/core.c | 33 ++++++++++++++++++++-------------
> > >>  drivers/usb/dwc3/core.h |  4 ++++
> > >>  drivers/usb/dwc3/host.c | 24 ++++++++++++++++++++++++
> > >>  3 files changed, 48 insertions(+), 13 deletions(-)
> > >>
> > >>diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> > >>index 950e238..cf377f5 100644
> > >>--- a/drivers/usb/dwc3/core.c
> > >>+++ b/drivers/usb/dwc3/core.c
> > >>@@ -33,6 +33,7 @@
> > >>  #include <linux/usb/gadget.h>
> > >>  #include <linux/usb/of.h>
> > >>  #include <linux/usb/otg.h>
> > >>+#include <linux/usb/hcd.h>
> > >This is not needed anymore
> > >
> > >>  #include "core.h"
> > >>  #include "gadget.h"
> > >>@@ -1787,6 +1788,7 @@ static int dwc3_probe(struct platform_device *pdev)
> > >>  	platform_set_drvdata(pdev, dwc);
> > >>  	dwc3_cache_hwparams(dwc);
> > >>+	device_init_wakeup(&pdev->dev, of_property_read_bool(dev->of_node, "wakeup-source"));
> > >>  	spin_lock_init(&dwc->lock);
> > >>  	mutex_init(&dwc->mutex);
> > >>@@ -1936,6 +1938,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
> > >>  {
> > >>  	unsigned long	flags;
> > >>  	u32 reg;
> > >>+	struct usb_hcd  *hcd = platform_get_drvdata(dwc->xhci);
> > >This isn't used anymore, delete it
> > My bad, Will fix this in next version.
> > >>  	switch (dwc->current_dr_role) {
> > >>  	case DWC3_GCTL_PRTCAP_DEVICE:
> > >>@@ -1948,10 +1951,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
> > >>  		dwc3_core_exit(dwc);
> > >>  		break;
> > >>  	case DWC3_GCTL_PRTCAP_HOST:
> > >>-		if (!PMSG_IS_AUTO(msg)) {
> > >>-			dwc3_core_exit(dwc);
> > >>-			break;
> > >>-		}
> > >>+		dwc3_check_phy_speed_mode(dwc);
> > >>  		/* Let controller to suspend HSPHY before PHY driver suspends */
> > >>  		if (dwc->dis_u2_susphy_quirk ||
> > >>@@ -1967,6 +1967,16 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
> > >>  		phy_pm_runtime_put_sync(dwc->usb2_generic_phy);
> > >>  		phy_pm_runtime_put_sync(dwc->usb3_generic_phy);
> > >>+
> > >>+		if (!PMSG_IS_AUTO(msg)) {
> > >>+			if (device_may_wakeup(dwc->dev) &&
> > >>+					device_wakeup_path(dwc->dev)) {
> > >nit: the indentation is odd, align it with device_may_wakeup()?
> > Sure, Will take care of it.
> > >>+				dwc->phy_power_off = false;
> > >>+			} else {
> > >>+				dwc->phy_power_off = true;
> > >>+				dwc3_core_exit(dwc);
> > >As commented earlier, taking the controller and PHYs completely down causes a
> > >significant power draw in some USB clients. Let's clarify what the specific
> > >benefits are of doing dwc3_core_exit() vs. entering a low power mode.
> > Sure, once we come to a conclusion on this, I will refresh the patches.
> 
> I think, Matthias is asking you to clarify in the commit description. we can
> even quote Matthias observations.

Actually I would like to have a discussion about the benefits of powering down
the controller and PHYs vs. entering a low power state. Maybe there are good
reasons for powering everything down (e.g. significant power savings), but
as we have seen there are also significant downsides, so let's make sure
we understand both.
Matthias Kaehlcke May 6, 2022, 4:51 p.m. UTC | #5 
On Fri, May 06, 2022 at 08:51:22AM -0700, Matthias Kaehlcke wrote:
> On Fri, May 06, 2022 at 10:44:48AM +0530, Pavan Kondeti wrote:
> > On Fri, May 06, 2022 at 10:41:01AM +0530, Krishna Kurapati PSSNV wrote:
> > > 
> > > On 5/6/2022 4:18 AM, Matthias Kaehlcke wrote:
> > > >On Thu, May 05, 2022 at 02:26:10PM +0530, Krishna Kurapati wrote:
> > > >>From: Sandeep Maheswaram <quic_c_sanm@quicinc.com>
> > > >>
> > > >>During suspend read the status of all port and set hs phy mode
> > > >>based on current speed. Use this hs phy mode to configure wakeup
> > > >>interrupts in qcom glue driver.
> > > >>
> > > >>Check wakeup-source property for dwc3 core node to set the
> > > >>wakeup capability. Drop the device_init_wakeup call from
> > > >>runtime suspend and resume.
> > > >>
> > > >>Also check during suspend if any wakeup capable devices are
> > > >>connected to the controller (directly or through hubs), if there
> > > >>are none set a flag to indicate that the PHY is powered
> > > >>down during suspend.
> > > >>
> > > >>Signed-off-by: Sandeep Maheswaram <quic_c_sanm@quicinc.com>
> > > >>Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
> > > >>---
> > > >>  drivers/usb/dwc3/core.c | 33 ++++++++++++++++++++-------------
> > > >>  drivers/usb/dwc3/core.h |  4 ++++
> > > >>  drivers/usb/dwc3/host.c | 24 ++++++++++++++++++++++++
> > > >>  3 files changed, 48 insertions(+), 13 deletions(-)
> > > >>
> > > >>diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> > > >>index 950e238..cf377f5 100644
> > > >>--- a/drivers/usb/dwc3/core.c
> > > >>+++ b/drivers/usb/dwc3/core.c
> > > >>@@ -33,6 +33,7 @@
> > > >>  #include <linux/usb/gadget.h>
> > > >>  #include <linux/usb/of.h>
> > > >>  #include <linux/usb/otg.h>
> > > >>+#include <linux/usb/hcd.h>
> > > >This is not needed anymore
> > > >
> > > >>  #include "core.h"
> > > >>  #include "gadget.h"
> > > >>@@ -1787,6 +1788,7 @@ static int dwc3_probe(struct platform_device *pdev)
> > > >>  	platform_set_drvdata(pdev, dwc);
> > > >>  	dwc3_cache_hwparams(dwc);
> > > >>+	device_init_wakeup(&pdev->dev, of_property_read_bool(dev->of_node, "wakeup-source"));
> > > >>  	spin_lock_init(&dwc->lock);
> > > >>  	mutex_init(&dwc->mutex);
> > > >>@@ -1936,6 +1938,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
> > > >>  {
> > > >>  	unsigned long	flags;
> > > >>  	u32 reg;
> > > >>+	struct usb_hcd  *hcd = platform_get_drvdata(dwc->xhci);
> > > >This isn't used anymore, delete it
> > > My bad, Will fix this in next version.
> > > >>  	switch (dwc->current_dr_role) {
> > > >>  	case DWC3_GCTL_PRTCAP_DEVICE:
> > > >>@@ -1948,10 +1951,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
> > > >>  		dwc3_core_exit(dwc);
> > > >>  		break;
> > > >>  	case DWC3_GCTL_PRTCAP_HOST:
> > > >>-		if (!PMSG_IS_AUTO(msg)) {
> > > >>-			dwc3_core_exit(dwc);
> > > >>-			break;
> > > >>-		}
> > > >>+		dwc3_check_phy_speed_mode(dwc);
> > > >>  		/* Let controller to suspend HSPHY before PHY driver suspends */
> > > >>  		if (dwc->dis_u2_susphy_quirk ||
> > > >>@@ -1967,6 +1967,16 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
> > > >>  		phy_pm_runtime_put_sync(dwc->usb2_generic_phy);
> > > >>  		phy_pm_runtime_put_sync(dwc->usb3_generic_phy);
> > > >>+
> > > >>+		if (!PMSG_IS_AUTO(msg)) {
> > > >>+			if (device_may_wakeup(dwc->dev) &&
> > > >>+					device_wakeup_path(dwc->dev)) {
> > > >nit: the indentation is odd, align it with device_may_wakeup()?
> > > Sure, Will take care of it.
> > > >>+				dwc->phy_power_off = false;
> > > >>+			} else {
> > > >>+				dwc->phy_power_off = true;
> > > >>+				dwc3_core_exit(dwc);
> > > >As commented earlier, taking the controller and PHYs completely down causes a
> > > >significant power draw in some USB clients. Let's clarify what the specific
> > > >benefits are of doing dwc3_core_exit() vs. entering a low power mode.
> > > Sure, once we come to a conclusion on this, I will refresh the patches.
> > 
> > I think, Matthias is asking you to clarify in the commit description. we can
> > even quote Matthias observations.
> 
> Actually I would like to have a discussion about the benefits of powering down
> the controller and PHYs vs. entering a low power state. Maybe there are good
> reasons for powering everything down (e.g. significant power savings), but
> as we have seen there are also significant downsides, so let's make sure
> we understand both.

I found this, as I commented on the other thread:

  commit c4a5153e87fdf6805f63ff57556260e2554155a5
  Author: Manu Gautam <mgautam@codeaurora.org>
  Date:   Thu Jan 18 16:54:30 2018 +0530

  usb: dwc3: core: Power-off core/PHYs on system_suspend in host mode

  Commit 689bf72c6e0d ("usb: dwc3: Don't reinitialize core during
  host bus-suspend/resume") updated suspend/resume routines to not
  power_off and reinit PHYs/core for host mode.
  It broke platforms that rely on DWC3 core to power_off PHYs to
  enter low power state on system suspend.

  Perform dwc3_core_exit/init only during host mode system_suspend/
  resume to addresses power regression from above mentioned patch
  and also allow USB session to stay connected across
  runtime_suspend/resume in host mode. While at it also replace
  existing checks for HOST only dr_mode with current_dr_role to
  have similar core driver behavior for both Host-only and DRD+Host
  configurations.

  Fixes: 689bf72c6e0d ("usb: dwc3: Don't reinitialize core during host bus-suspend/resume")
  Reviewed-by: Roger Quadros <rogerq@ti.com>
  Signed-off-by: Manu Gautam <mgautam@codeaurora.org>
  Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>


So apparently powering off the core and PHYs is needed on some
platforms.

Let's move forward with the core/PHYs off for now and try to
come up with a solution (e.g. a DT property that indicates
that the core/PHYs can remain powererd) in a separate
patch/series.