linux-kernel - Re: [v15 3/6] usb: dwc3: core: Host wake up support from system suspend

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Date:   Fri, 6 May 2022 10:41:01 +0530
From:   Krishna Kurapati PSSNV <quic_kriskura@...cinc.com>
To:     Matthias Kaehlcke <mka@...omium.org>
CC:     Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Felipe Balbi <balbi@...nel.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Doug Anderson <dianders@...omium.org>,
        Mathias Nyman <mathias.nyman@...el.com>,
        <devicetree@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        <linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-pm@...r.kernel.org>, <quic_pkondeti@...cinc.com>,
        <quic_ppratap@...cinc.com>, <quic_vpulyala@...cinc.com>,
        Sandeep Maheswaram <quic_c_sanm@...cinc.com>
Subject: Re: [v15 3/6] usb: dwc3: core: Host wake up support from system
 suspend


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@...cinc.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@...cinc.com>
>> Signed-off-by: Krishna Kurapati <quic_kriskura@...cinc.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.