[RFC][PATCH v3 02/11] usb: dwc3: Execute GCTL Core Soft Reset while switch modes

John Stultz
2019-10-16T03:33:50Z

From: Yu Chen <chenyu56@huawei.com>

On the HiKey960, we need to do a GCTL soft reset when
switching modes.

Jack Pham also noted that in the Synopsys databook it
mentions performing a GCTL CoreSoftReset when changing the
PrtCapDir between device & host modes.

So this patch always does a GCTL Core Soft Reset when
changing the mode.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
CC: ShuFan Lee <shufan_lee@richtek.com>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Chunfeng Yun <chunfeng.yun@mediatek.com>
Cc: Yu Chen <chenyu56@huawei.com>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Jun Li <lijun.kernel@gmail.com>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jack Pham <jackp@codeaurora.org>
Cc: linux-usb@vger.kernel.org
Cc: devicetree@vger.kernel.org
Signed-off-by: Yu Chen <chenyu56@huawei.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
v3: Remove quirk conditional, as Jack Pham noted the
Synopsis databook states this should be done generally.
Also, at Jacks' suggestion, make the reset call before
changing the prtcap direction.
---
drivers/usb/dwc3/core.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 999ce5e84d3c..a039e35ec7ad 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -112,6 +112,19 @@ void dwc3_set_prtcap(struct dwc3 *dwc, u32 mode)
dwc->current_dr_role = mode;
}

+static void dwc3_gctl_core_soft_reset(struct dwc3 *dwc)
+{
+ u32 reg;
+
+ reg = dwc3_readl(dwc->regs, DWC3_GCTL);
+ reg |= DWC3_GCTL_CORESOFTRESET;
+ dwc3_writel(dwc->regs, DWC3_GCTL, reg);
+
+ reg = dwc3_readl(dwc->regs, DWC3_GCTL);
+ reg &= ~DWC3_GCTL_CORESOFTRESET;
+ dwc3_writel(dwc->regs, DWC3_GCTL, reg);
+}
+
static void __dwc3_set_mode(struct work_struct *work)
{
struct dwc3 *dwc = work_to_dwc(work);
@@ -154,6 +167,9 @@ static void __dwc3_set_mode(struct work_struct *work)

spin_lock_irqsave(&dwc->lock, flags);

+ /* Execute a GCTL Core Soft Reset when switch mode */
+ dwc3_gctl_core_soft_reset(dwc);
+
dwc3_set_prtcap(dwc, dwc->desired_dr_role);

spin_unlock_irqrestore(&dwc->lock, flags);
--
2.17.1