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Date: Mon, 20 May 2019 10:56:04 -0700
From: Douglas Anderson <dianders@...omium.org>
To: Minas Harutyunyan <hminas@...opsys.com>,
Felipe Balbi <felipe.balbi@...ux.intel.com>, heiko@...ech.de
Cc: Alan Stern <stern@...land.harvard.edu>,
Artur Petrosyan <Arthur.Petrosyan@...opsys.com>,
amstan@...omium.org, linux-rockchip@...ts.infradead.org,
William Wu <william.wu@...k-chips.com>,
linux-usb@...r.kernel.org, Stefan Wahren <stefan.wahren@...e.com>,
Randy Li <ayaka@...lik.info>, zyw@...k-chips.com,
mka@...omium.org, ryandcase@...omium.org,
Amelie Delaunay <amelie.delaunay@...com>, jwerner@...omium.org,
Elaine Zhang <zhangqing@...k-chips.com>,
Douglas Anderson <dianders@...omium.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
linux-kernel@...r.kernel.org
Subject: [PATCH v3 2/3] USB: dwc2: Don't turn off the usbphy in suspend if wakeup is enabled
If the 'snps,need-phy-for-wake' is set in the device tree then:
- We know that we can wakeup, so call device_set_wakeup_capable().
The USB core will use this knowledge to enable wakeup by default.
- We know that we should keep the PHY on during suspend if something
on our root hub needs remote wakeup. This requires the patch (USB:
Export usb_wakeup_enabled_descendants()). Note that we don't keep
the PHY on at suspend time if it's not needed because it would be a
power draw.
If we later find some users of dwc2 that can support wakeup without
keeping the PHY on we may want to add a way to call
device_set_wakeup_capable() without keeping the PHY on at suspend
time.
Signed-off-by: Douglas Anderson <dianders@...omium.org>
Signed-off-by: Chris Zhong <zyw@...k-chips.com>
---
For relevant prior discussion of this idea, see:
https://lkml.kernel.org/r/1436207224-21849-4-git-send-email-dianders@chromium.org
If I'm reading all the responses correctly folks were of the opinion
that this patch is still the right way to go.
Changes in v3:
- Fixed kbuild test robot error.
Changes in v2:
- Rebased to mainline atop rk3288 remote wake quirk series.
drivers/usb/dwc2/core.h | 8 ++++++++
drivers/usb/dwc2/hcd.c | 19 +++++++++++++++++++
drivers/usb/dwc2/platform.c | 23 ++++++++++++++++++++---
3 files changed, 47 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index 152ac41dfb2d..d08d070a0fb6 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -861,6 +861,9 @@ struct dwc2_hregs_backup {
* @hibernated: True if core is hibernated
* @reset_phy_on_wake: Quirk saying that we should assert PHY reset on a
* remote wakeup.
+ * @phy_off_for_suspend: Status of whether we turned the PHY off at suspend.
+ * @need_phy_for_wake: Quirk saying that we should keep the PHY on at
+ * suspend if we need USB to wake us up.
* @frame_number: Frame number read from the core. For both device
* and host modes. The value ranges are from 0
* to HFNUM_MAX_FRNUM.
@@ -1049,6 +1052,8 @@ struct dwc2_hsotg {
unsigned int ll_hw_enabled:1;
unsigned int hibernated:1;
unsigned int reset_phy_on_wake:1;
+ unsigned int need_phy_for_wake:1;
+ unsigned int phy_off_for_suspend:1;
u16 frame_number;
struct phy *phy;
@@ -1438,6 +1443,7 @@ int dwc2_restore_host_registers(struct dwc2_hsotg *hsotg);
int dwc2_host_enter_hibernation(struct dwc2_hsotg *hsotg);
int dwc2_host_exit_hibernation(struct dwc2_hsotg *hsotg,
int rem_wakeup, int reset);
+bool dwc2_host_can_poweroff_phy(struct dwc2_hsotg *dwc2);
static inline void dwc2_host_schedule_phy_reset(struct dwc2_hsotg *hsotg)
{ schedule_work(&hsotg->phy_reset_work); }
#else
@@ -1463,6 +1469,8 @@ static inline int dwc2_host_enter_hibernation(struct dwc2_hsotg *hsotg)
static inline int dwc2_host_exit_hibernation(struct dwc2_hsotg *hsotg,
int rem_wakeup, int reset)
{ return 0; }
+static inline bool dwc2_host_can_poweroff_phy(struct dwc2_hsotg *dwc2)
+{ return false; }
static inline void dwc2_host_schedule_phy_reset(struct dwc2_hsotg *hsotg) {}
#endif
diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index b50ec3714fd8..cc918fe7ddb8 100644
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -5578,3 +5578,22 @@ int dwc2_host_exit_hibernation(struct dwc2_hsotg *hsotg, int rem_wakeup,
dev_dbg(hsotg->dev, "Host hibernation restore complete\n");
return ret;
}
+
+bool dwc2_host_can_poweroff_phy(struct dwc2_hsotg *dwc2)
+{
+ struct usb_device *root_hub = dwc2_hsotg_to_hcd(dwc2)->self.root_hub;
+
+ /* If the controller isn't allowed to wakeup then we can power off. */
+ if (!device_may_wakeup(dwc2->dev))
+ return true;
+
+ /*
+ * We don't want to power off the PHY if something under the
+ * root hub has wakeup enabled.
+ */
+ if (usb_wakeup_enabled_descendants(root_hub))
+ return false;
+
+ /* No reason to keep the PHY powered, so allow poweroff */
+ return true;
+}
diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
index d10a7f8daec3..3e6c3c8a32ff 100644
--- a/drivers/usb/dwc2/platform.c
+++ b/drivers/usb/dwc2/platform.c
@@ -447,6 +447,10 @@ static int dwc2_driver_probe(struct platform_device *dev)
if (retval)
goto error;
+ hsotg->need_phy_for_wake =
+ of_property_read_bool(dev->dev.of_node,
+ "snps,need-phy-for-wake");
+
/*
* Reset before dwc2_get_hwparams() then it could get power-on real
* reset value form registers.
@@ -478,6 +482,14 @@ static int dwc2_driver_probe(struct platform_device *dev)
hsotg->gadget_enabled = 1;
}
+ /*
+ * If we need PHY for wakeup we must be wakeup capable.
+ * When we have a device that can wake without the PHY we
+ * can adjust this condition.
+ */
+ if (hsotg->need_phy_for_wake)
+ device_set_wakeup_capable(&dev->dev, true);
+
hsotg->reset_phy_on_wake =
of_property_read_bool(dev->dev.of_node,
"snps,reset-phy-on-wake");
@@ -516,13 +528,17 @@ static int dwc2_driver_probe(struct platform_device *dev)
static int __maybe_unused dwc2_suspend(struct device *dev)
{
struct dwc2_hsotg *dwc2 = dev_get_drvdata(dev);
+ bool is_device_mode = dwc2_is_device_mode(dwc2);
int ret = 0;
- if (dwc2_is_device_mode(dwc2))
+ if (is_device_mode)
dwc2_hsotg_suspend(dwc2);
- if (dwc2->ll_hw_enabled)
+ if (dwc2->ll_hw_enabled &&
+ (is_device_mode || dwc2_host_can_poweroff_phy(dwc2))) {
ret = __dwc2_lowlevel_hw_disable(dwc2);
+ dwc2->phy_off_for_suspend = true;
+ }
return ret;
}
@@ -532,11 +548,12 @@ static int __maybe_unused dwc2_resume(struct device *dev)
struct dwc2_hsotg *dwc2 = dev_get_drvdata(dev);
int ret = 0;
- if (dwc2->ll_hw_enabled) {
+ if (dwc2->phy_off_for_suspend && dwc2->ll_hw_enabled) {
ret = __dwc2_lowlevel_hw_enable(dwc2);
if (ret)
return ret;
}
+ dwc2->phy_off_for_suspend = false;
if (dwc2_is_device_mode(dwc2))
ret = dwc2_hsotg_resume(dwc2);
--
2.21.0.1020.gf2820cf01a-goog
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