Re: [v16 2/5] usb: dwc3: core: Host wake up support from system suspend

[Pavan Kondeti]

On Fri, May 13, 2022 at 09:28:16AM +0530, Krishna Kurapati PSSNV wrote:
> 
> On 5/13/2022 4:10 AM, Matthias Kaehlcke wrote:
> >On Thu, May 12, 2022 at 11:53:19PM +0530, Krishna Kurapati wrote:
> >>From: Sandeep Maheswaram <quic_c_sanm@xxxxxxxxxxx>
> >>
> >>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@xxxxxxxxxxx>
> >>Signed-off-by: Krishna Kurapati <quic_kriskura@xxxxxxxxxxx>
> >>---
> >>  drivers/usb/dwc3/core.c | 30 +++++++++++++++++-------------
> >>  drivers/usb/dwc3/core.h |  4 ++++
> >>  drivers/usb/dwc3/host.c | 24 ++++++++++++++++++++++++
> >>  3 files changed, 45 insertions(+), 13 deletions(-)
> >>
> >>diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> >>index 01115df..8bcabc5 100644
> >>--- a/drivers/usb/dwc3/core.c
> >>+++ b/drivers/usb/dwc3/core.c
> >>@@ -1785,6 +1785,7 @@ 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);
> >>@@ -1946,10 +1947,7 @@ 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 ||
> >>@@ -1965,6 +1963,15 @@ 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))
> >I think this should be device_can_wakeup(), i.e. hardware capability instead of
> >device policy. A drawback of powering the PHYs off is that it causes a high
> >power consumption of certain peripherals if VBUS is still supplied, so this
> >should be limited to platforms where the PHYs must be powered off (using wakeup
> >capability as a proxy for now).
> Thnaks Mathias for the review. Will make this change in the next patchset.
> >>+				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 */
> >>@@ -2008,11 +2015,12 @@ 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) {
> >>+				ret = dwc3_core_init_for_resume(dwc);
> >>+				if (ret)
> >>+					return ret;
> >>+				dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_HOST);
> >>+			}
> >>  		}
> >>  		/* Restore GUSB2PHYCFG bits that were modified in suspend */
> >>  		reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
> >>@@ -2084,8 +2092,6 @@ static int dwc3_runtime_suspend(struct device *dev)
> >>  	if (ret)
> >>  		return ret;
> >>-	device_init_wakeup(dev, true);
> >>-
> >>  	return 0;
> >>  }
> >>@@ -2094,8 +2100,6 @@ static int dwc3_runtime_resume(struct device *dev)
> >>  	struct dwc3     *dwc = dev_get_drvdata(dev);
> >>  	int		ret;
> >>-	device_init_wakeup(dev, false);
> >>-
> >>  	ret = dwc3_resume_common(dwc, PMSG_AUTO_RESUME);
> >>  	if (ret)
> >>  		return ret;
> >>diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> >>index 81c486b..37397a8 100644
> >>--- a/drivers/usb/dwc3/core.h
> >>+++ b/drivers/usb/dwc3/core.h
> >>@@ -1155,6 +1155,9 @@ struct dwc3 {
> >>  	bool			phys_ready;
> >>+	unsigned int            hs_phy_mode;
> >>+	bool			phy_power_off;
> >>+
> >>  	struct ulpi		*ulpi;
> >>  	bool			ulpi_ready;
> >>@@ -1539,6 +1542,7 @@ int dwc3_core_soft_reset(struct dwc3 *dwc);
> >>  #if IS_ENABLED(CONFIG_USB_DWC3_HOST) || IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE)
> >>  int dwc3_host_init(struct dwc3 *dwc);
> >>  void dwc3_host_exit(struct dwc3 *dwc);
> >>+void dwc3_check_phy_speed_mode(struct dwc3 *dwc);
> >>  #else
> >>  static inline int dwc3_host_init(struct dwc3 *dwc)
> >>  { return 0; }
> >>diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
> >>index f56c30c..e19b40a 100644
> >>--- a/drivers/usb/dwc3/host.c
> >>+++ b/drivers/usb/dwc3/host.c
> >>@@ -12,6 +12,7 @@
> >>  #include <linux/platform_device.h>
> >>  #include "core.h"
> >>+#include "../host/xhci.h"
> >>  static void dwc3_host_fill_xhci_irq_res(struct dwc3 *dwc,
> >>  					int irq, char *name)
> >>@@ -136,3 +137,26 @@ void dwc3_host_exit(struct dwc3 *dwc)
> >>  {
> >>  	platform_device_unregister(dwc->xhci);
> >>  }
> >>+
> >>+void dwc3_check_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 * NUM_PORT_REGS);
> >>+		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;
> >>+		}
> >>+	}
> >>+}
> >I anticipate that it might raise concerns from maintainers that
> >dwc3_check_phy_speed_mode() accesses xHCI data structures and
> >registers directly. Could there be a generic HCD API that provides
> >this functionality (if implemented by the specific HCD)?
> 
> Hi Mathias, we are not sure if there is any such API present currently.
> 
> Hi Alan, can you help suggest any API (if present) that we can reuse here to
> avoid
> 
> xhci registers and structs here in dwc3.
> 

We can probably do something like below to query the speed. This avoids adding
another API and does not touch the underlying registers.

Pls define enum usb_device_speed usb2_speed in dwc3 structure.

diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
index f29a264..fed1c58 100644
--- a/drivers/usb/dwc3/host.c
+++ b/drivers/usb/dwc3/host.c
@@ -9,9 +9,29 @@
 
 #include <linux/acpi.h>
 #include <linux/platform_device.h>
+#include <linux/usb.h>
 
 #include "core.h"
 
+void dwc3_update_hs_phy_speed(struct dwc3 *dwc)
+{
+	struct usb_hcd	*hcd = platform_get_drvdata(dwc->xhci);
+	struct usb_device *udev;
+
+	/*
+	 * It is possible to query the speed of all children of
+	 * USB2.0 root hub via usb_hub_for_each_child(). DWC3 code
+	 * currently supports only 1 port per controller. So
+	 * this is sufficient.
+	 */
+	udev = usb_hub_find_child(hcd->self.root_hub, 1);
+
+	if (udev)
+		dwc->usb2_speed = udev->speed;
+	else
+		dwc->usb2_speed = USB_SPEED_UNKNOWN;
+}
+
 static int dwc3_host_get_irq(struct dwc3 *dwc)
 {
 	struct platform_device	*dwc3_pdev = to_platform_device(dwc->dev);


Thanks,
Pavan