From: Yu Chen <cheny...@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 <gre...@linuxfoundation.org>
Cc: Rob Herring <robh...@kernel.org>
Cc: Mark Rutland <mark.rutl...@arm.com>
CC: ShuFan Lee <shufan_...@richtek.com>
Cc: Heikki Krogerus <heikki.kroge...@linux.intel.com>
Cc: Suzuki K Poulose <suzuki.poul...@arm.com>
Cc: Chunfeng Yun <chunfeng....@mediatek.com>
Cc: Yu Chen <cheny...@huawei.com>
Cc: Felipe Balbi <ba...@kernel.org>
Cc: Hans de Goede <hdego...@redhat.com>
Cc: Andy Shevchenko <andy.shevche...@gmail.com>
Cc: Jun Li <lijun.ker...@gmail.com>
Cc: Valentin Schneider <valentin.schnei...@arm.com>
Cc: Jack Pham <ja...@codeaurora.org>
Cc: linux-...@vger.kernel.org
Cc: devicet...@vger.kernel.org
Signed-off-by: Yu Chen <cheny...@huawei.com>
Signed-off-by: John Stultz <john.stu...@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

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