From: Yu Chen <[email protected]> With the current dwc3 code on the HiKey960 we often see the COREIDLE flag get stuck off in __dwc3_gadget_start(), which seems to prevent the reset irq and causes the USB gadget to fail to initialize.
We had seen occasional initialization failures with older kernels but with recent 5.x era kernels it seemed to be becoming much more common, so I dug back through some older trees and realized I dropped this quirk from Yu Chen during upstreaming as I couldn't provide a proper rational for it and it didn't seem to be necessary. I now realize I was wrong. On the upside, I can now understand more why such a quirk is needed. So to address a quirk in the DesignWare USB3 DRD Core of Hisilicon Kirin SoCs, this patch adds a quirk flag which executes a GCTL soft reset when we switch modes. Cc: Felipe Balbi <[email protected]> Cc: Tejas Joglekar <[email protected]> Cc: Yang Fei <[email protected]> Cc: YongQin Liu <[email protected]> Cc: Andrzej Pietrasiewicz <[email protected]> Cc: Thinh Nguyen <[email protected]> Cc: Jun Li <[email protected]> Cc: Mauro Carvalho Chehab <[email protected]> Cc: Rob Herring <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: [email protected] Cc: [email protected] Signed-off-by: Yu Chen <[email protected]> Signed-off-by: John Stultz <[email protected]> --- .../devicetree/bindings/usb/dwc3.txt | 3 +++ drivers/usb/dwc3/core.c | 19 +++++++++++++++++++ drivers/usb/dwc3/core.h | 1 + 3 files changed, 23 insertions(+) diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt index 1aae2b6160c1..f435bae0f172 100644 --- a/Documentation/devicetree/bindings/usb/dwc3.txt +++ b/Documentation/devicetree/bindings/usb/dwc3.txt @@ -81,6 +81,9 @@ Optional properties: - snps,dis-split-quirk: when set, change the way URBs are handled by the driver. Needed to avoid -EPROTO errors with usbhid on some devices (Hikey 970). + - snps,gctl-reset-quirk: When set, execute a soft reset on mode changes. + Needed to avoid COREIDLE getting stuck off and the + gadget to fail to initialize (HiKey960). - snps,is-utmi-l1-suspend: true when DWC3 asserts output signal utmi_l1_suspend_n, false when asserts utmi_sleep_n - snps,hird-threshold: HIRD threshold diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index bdf0925da6b6..b138c67e3892 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -114,6 +114,19 @@ void dwc3_set_prtcap(struct dwc3 *dwc, u32 mode) dwc->current_dr_role = mode; } +static void dwc3_gctl_core_soft_reset(struct dwc3 *dwc) +{ + int 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); @@ -178,6 +191,10 @@ static void __dwc3_set_mode(struct work_struct *work) } break; case DWC3_GCTL_PRTCAP_DEVICE: + /* Execute a GCTL Core Soft Reset when switch mode */ + if (dwc->gctl_reset_quirk) + dwc3_gctl_core_soft_reset(dwc); + dwc3_event_buffers_setup(dwc); if (dwc->usb2_phy) @@ -1357,6 +1374,8 @@ static void dwc3_get_properties(struct dwc3 *dwc) dwc->dis_split_quirk = device_property_read_bool(dev, "snps,dis-split-quirk"); + dwc->gctl_reset_quirk = device_property_read_bool(dev, + "snps,gctl-reset-quirk"); dwc->lpm_nyet_threshold = lpm_nyet_threshold; dwc->tx_de_emphasis = tx_de_emphasis; diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h index 74323b10a64a..993f243aedc8 100644 --- a/drivers/usb/dwc3/core.h +++ b/drivers/usb/dwc3/core.h @@ -1252,6 +1252,7 @@ struct dwc3 { unsigned dis_metastability_quirk:1; unsigned dis_split_quirk:1; + unsigned gctl_reset_quirk:1; u16 imod_interval; }; -- 2.17.1
