Re: [PATCH v11 2/5] usb: dwc3: core: Host wake up support from system suspend

["Sandeep Maheswaram (Temp)" <quic_c_sanm@quicinc.com>]

On 3/23/2022 11:37 PM, Matthias Kaehlcke wrote:
> On Tue, Mar 22, 2022 at 12:37:53PM +0530, Sandeep Maheswaram wrote:
>> During suspend read the status of all port and make sure the PHYs
>> are in the correct mode based on current speed.
>> Phy interrupt masks are set based on this mode. Keep track of the mode
>> of the HS PHY to be able to configure wakeup properly.
>>
>> 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>
>> ---
>>   drivers/usb/dwc3/core.c | 54 ++++++++++++++++++++++++++++++++++++++++---------
>>   1 file changed, 45 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>> index 1170b80..232a734 100644
>> --- a/drivers/usb/dwc3/core.c
>> +++ b/drivers/usb/dwc3/core.c
>> @@ -32,12 +32,14 @@
>>   #include <linux/usb/gadget.h>
>>   #include <linux/usb/of.h>
>>   #include <linux/usb/otg.h>
>> +#include <linux/usb/hcd.h>
>>   
>>   #include "core.h"
>>   #include "gadget.h"
>>   #include "io.h"
>>   
>>   #include "debug.h"
>> +#include "../host/xhci.h"
>>   
>>   #define DWC3_DEFAULT_AUTOSUSPEND_DELAY	5000 /* ms */
>>   
>> @@ -1861,10 +1863,36 @@ static int dwc3_core_init_for_resume(struct dwc3 *dwc)
>>   	return ret;
>>   }
>>   
>> +static void dwc3_set_phy_speed_mode(struct dwc3 *dwc)
>> +{
>> +
>> +	int i, num_ports;
>> +	u32 reg;
>> +	struct usb_hcd	*hcd = platform_get_drvdata(dwc->xhci);
>> +	struct xhci_hcd	*xhci_hcd = hcd_to_xhci(hcd);
>> +
>> +	dwc->hs_phy_mode = 0;
>> +
>> +	reg = readl(&xhci_hcd->cap_regs->hcs_params1);
>> +
>> +	num_ports = HCS_MAX_PORTS(reg);
>> +	for (i = 0; i < num_ports; i++) {
>> +		reg = readl(&xhci_hcd->op_regs->port_status_base + i * 0x04);
> s/0x04/NUM_PORT_REGS/
Okay. Will update in next version.
>
>> +		if (reg & PORT_PE) {
>> +			if (DEV_HIGHSPEED(reg) || DEV_FULLSPEED(reg))
>> +				dwc->hs_phy_mode |= PHY_MODE_USB_HOST_HS;
>> +			else if (DEV_LOWSPEED(reg))
>> +				dwc->hs_phy_mode |= PHY_MODE_USB_HOST_LS;
>> +		}
>> +	}
>> +	phy_set_mode(dwc->usb2_generic_phy, dwc->hs_phy_mode);
>> +}
>> +
>>   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);
>>   
>>   	switch (dwc->current_dr_role) {
>>   	case DWC3_GCTL_PRTCAP_DEVICE:
>> @@ -1877,10 +1905,7 @@ 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_set_phy_speed_mode(dwc);
>>   
>>   		/* Let controller to suspend HSPHY before PHY driver suspends */
>>   		if (dwc->dis_u2_susphy_quirk ||
>> @@ -1896,6 +1921,16 @@ 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->xhci->dev) &&
> Does the xHCI actually provide the correct information? I think Brian brought
> up earlier that xhci-plat always marks the xHCI as wakeup capable, regardless
> of whether the specific implementation actually supports wakeup. So a dwc3
> without wakeup support would keep the PHY and the dwc3 active during suspend
> if wakeup capable devices are connected (unless the admin disabled wakeup),
> even though wakeup it doesn't support wakeup.
>
> Using the wakeup capability/policy of the xHCI to make decisions in the dwc3
> driver might still be the best we can do with the weird driver split over 3
> drivers for dwc3. Maybe the dwc3 could pass the actual capability to wake up
> to the xHCI through a property_entry? Then again, it's actually the 'glue'
> driver (dwc3-qcom) who knows about the actual wakeup capability, and not the
> dwc3 core/host ...
Will check if we can do something regarding this.
>
>> +			    usb_wakeup_enabled_descendants(hcd->self.root_hub)) {
>> +				dwc->phy_power_off = false;
>> +			} else {
>> +				dwc->phy_power_off = true;
>> +				dwc3_core_exit(dwc);
>> +			}
>> +		}
>>   		break;
>>   	case DWC3_GCTL_PRTCAP_OTG:
>>   		/* do nothing during runtime_suspend */
>> @@ -1939,11 +1974,12 @@ static int dwc3_resume_common(struct dwc3 *dwc, pm_message_t msg)
>>   		break;
>>   	case DWC3_GCTL_PRTCAP_HOST:
>>   		if (!PMSG_IS_AUTO(msg)) {
>> -			ret = dwc3_core_init_for_resume(dwc);
>> -			if (ret)
>> -				return ret;
>> -			dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_HOST);
>> -			break;
>> +			if (dwc->phy_power_off) {
> nit: you could merge this with the outer if condition:
>
>       	       	if (!PMSG_IS_AUTO(msg) && dwc->phy_power_off) {
>
> it's also fine to leave as is.

Okay. Will update in next version.