From: Doug Anderson <dianders@xxxxxxxxxxxx>
On the rk3288 USB host-only port (the one that's not the OTG-enabled
port) the PHY can get into a bad state when a wakeup is asserted (not
just a wakeup from full system suspend but also a wakeup from
autosuspend). The problem is caused by a design fault in IC, Rockchip
have confirmed it and fix this problem in the future IC model.
We can get the PHY out of its bad state by asserting its "port reset",
but unfortunately that seems to assert a reset onto the USB bus so it
could confuse things if we don't actually deenumerate / reenumerate the
device.
We can also get the PHY out of its bad state by fully resetting it using
the reset from the CRU (clock reset unit), which does a more full
reset. The CRU-based reset appears to actually cause devices on the bus
to be removed and reinserted, which fixes the problem (albeit in a hacky
way).
It's unfortunate that we need to do a full re-enumeration of devices at
wakeup time, but this is better than alternative of letting the bus get
wedged.
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
Signed-off-by: Yunzhi Li <lyz@xxxxxxxxxxxxxx>
Reviewed-by: Randy Li <randy.li@xxxxxxxxxxxxxx>
---
Documentation/devicetree/bindings/usb/dwc2.txt | 7 +++++++
drivers/usb/dwc2/core.h | 5 +++++
drivers/usb/dwc2/core_intr.c | 14 ++++++++++++++
drivers/usb/dwc2/platform.c | 13 +++++++++++++
4 files changed, 39 insertions(+)
diff --git a/Documentation/devicetree/bindings/usb/dwc2.txt b/Documentation/devicetree/bindings/usb/dwc2.txt
index 20a68bf..40c63ae 100644
--- a/Documentation/devicetree/bindings/usb/dwc2.txt
+++ b/Documentation/devicetree/bindings/usb/dwc2.txt
@@ -20,6 +20,13 @@ Refer to clk/clock-bindings.txt for generic clock consumer properties
Optional properties:
- phys: phy provider specifier
- phy-names: shall be "usb2-phy"
+- snps,need-phy-full-reset-on-wake: if present indicates that we need to reset
+ the PHY when we detect a wakeup due to a hardware errata. If present you
+ must specify a "phy-full-reset" reset.
+
+Resets:
+- phy-full-reset (optional): Fully resets the PHY (Only used by rk3288 Soc).
+
Refer to phy/phy-bindings.txt for generic phy consumer properties
- dr_mode: shall be one of "host", "peripheral" and "otg"
Refer to usb/generic.txt
diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index dec0b21..951abe0 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -719,8 +719,11 @@ struct dwc2_hregs_backup {
* @hcd_enabled Host mode sub-driver initialization indicator.
* @gadget_enabled Peripheral mode sub-driver initialization indicator.
* @ll_hw_enabled Status of low-level hardware resources.
+ * @need_phy_full_reset_on_wake: Quirk saying that we should assert
+ * phy_full_reset on a remote wakeup.
* @phy: The otg phy transceiver structure for phy control.
* @uphy: The otg phy transceiver structure for old USB phy control.
+ * @phy_full_reset: Reset control for the PHY's "full reset".
* @plat: The platform specific configuration data. This can be removed once
* all SoCs support usb transceiver.
* @supplies: Definition of USB power supplies
@@ -853,9 +856,11 @@ struct dwc2_hsotg {
unsigned int hcd_enabled:1;
unsigned int gadget_enabled:1;
unsigned int ll_hw_enabled:1;
+ unsigned int need_phy_full_reset_on_wake:1;
struct phy *phy;
struct usb_phy *uphy;
+ struct reset_control *phy_full_reset;
struct dwc2_hsotg_plat *plat;
struct regulator_bulk_data supplies[ARRAY_SIZE(dwc2_hsotg_supply_names)];
u32 phyif;
diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c
index d85c5c9..53d8327 100644
--- a/drivers/usb/dwc2/core_intr.c
+++ b/drivers/usb/dwc2/core_intr.c
@@ -45,6 +45,7 @@
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/slab.h>
+#include <linux/reset.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>
@@ -379,6 +380,19 @@ static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
/* Restart the Phy Clock */
pcgcctl &= ~PCGCTL_STOPPCLK;
dwc2_writel(pcgcctl, hsotg->regs + PCGCTL);
+
+ /*
+ * If we've got this quirk then the PHY is stuck upon
+ * wakeup. Assert reset. This will propagate out and
+ * eventually we'll re-enumerate the device. Not great
+ * but the best we can do.
+ */
+ if (hsotg->need_phy_full_reset_on_wake) {
+ reset_control_assert(hsotg->phy_full_reset);
+ udelay(50);
+ reset_control_deassert(hsotg->phy_full_reset);
+ }
+
mod_timer(&hsotg->wkp_timer,
jiffies + msecs_to_jiffies(71));
} else {
diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
index fc6f525..d8894a1 100644
--- a/drivers/usb/dwc2/platform.c
+++ b/drivers/usb/dwc2/platform.c
@@ -45,6 +45,7 @@
#include <linux/platform_device.h>
#include <linux/phy/phy.h>
#include <linux/platform_data/s3c-hsotg.h>
+#include <linux/reset.h>
#include <linux/usb/of.h>
@@ -529,6 +530,18 @@ static int dwc2_driver_probe(struct platform_device *dev)
dev_dbg(&dev->dev, "mapped PA %08lx to VA %p\n",
(unsigned long)res->start, hsotg->regs);
+ hsotg->need_phy_full_reset_on_wake =
+ of_property_read_bool(dev->dev.of_node,
+ "snps,need-phy-full-reset-on-wake");
+ hsotg->phy_full_reset = devm_reset_control_get(hsotg->dev,
+ "phy-full-reset");
+ if (IS_ERR(hsotg->phy_full_reset) &&
+ hsotg->need_phy_full_reset_on_wake) {
+ dev_warn(hsotg->dev, "Missing phy full reset (%ld); skipping\n",
+ PTR_ERR(hsotg->phy_full_reset));
+ hsotg->need_phy_full_reset_on_wake = false;
+ }
+
retval = dwc2_lowlevel_hw_init(hsotg);
if (retval)
return retval;
--
2.7.4
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