From: Chris Morgan <[email protected]> DCTL.ULSTCHNGREQ is a write-only field. When doing a read-modify-write to DCTL, the driver must make sure that there's no unintended link state change request from whatever is read from DCTL.ULSTCHNGREQ. Set link state change to no-action when the driver writes to DCTL.
Note that this patch was submitted upstream in Linux in 2020 [1], and I've confirmed I need it in U-Boot to enable gadget mode. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/patch/drivers/usb/dwc3?id=5b738211fb59e114727381d07c647a77c0010996 Signed-off-by: Thinh Nguyen <[email protected]> Signed-off-by: Chris Morgan <[email protected]> --- drivers/usb/dwc3/gadget.c | 20 +++++++++----------- drivers/usb/dwc3/gadget.h | 14 ++++++++++++++ 2 files changed, 23 insertions(+), 11 deletions(-) diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 2b01113d54c..24ae0c232f6 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -62,7 +62,7 @@ int dwc3_gadget_set_test_mode(struct dwc3 *dwc, int mode) return -EINVAL; } - dwc3_writel(dwc->regs, DWC3_DCTL, reg); + dwc3_gadget_dctl_write_safe(dwc, reg); return 0; } @@ -1396,7 +1396,7 @@ static int dwc3_gadget_set_selfpowered(struct usb_gadget *g, static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on, int suspend) { u32 reg; - u32 timeout = 500; + u32 timeout = 2000; reg = dwc3_readl(dwc->regs, DWC3_DCTL); if (is_on) { @@ -1422,9 +1422,10 @@ static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on, int suspend) dwc->pullups_connected = false; } - dwc3_writel(dwc->regs, DWC3_DCTL, reg); + dwc3_gadget_dctl_write_safe(dwc, reg); do { + udelay(2000); reg = dwc3_readl(dwc->regs, DWC3_DSTS); if (is_on) { if (!(reg & DWC3_DSTS_DEVCTRLHLT)) @@ -1436,7 +1437,6 @@ static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on, int suspend) timeout--; if (!timeout) return -ETIMEDOUT; - udelay(1); } while (1); dev_vdbg(dwc->dev, "gadget %s data soft-%s\n", @@ -2137,10 +2137,8 @@ static void dwc3_gadget_disconnect_interrupt(struct dwc3 *dwc) reg = dwc3_readl(dwc->regs, DWC3_DCTL); reg &= ~DWC3_DCTL_INITU1ENA; - dwc3_writel(dwc->regs, DWC3_DCTL, reg); - reg &= ~DWC3_DCTL_INITU2ENA; - dwc3_writel(dwc->regs, DWC3_DCTL, reg); + dwc3_gadget_dctl_write_safe(dwc, reg); dwc3_disconnect_gadget(dwc); dwc->start_config_issued = false; @@ -2189,7 +2187,7 @@ static void dwc3_gadget_reset_interrupt(struct dwc3 *dwc) reg = dwc3_readl(dwc->regs, DWC3_DCTL); reg &= ~DWC3_DCTL_TSTCTRL_MASK; - dwc3_writel(dwc->regs, DWC3_DCTL, reg); + dwc3_gadget_dctl_write_safe(dwc, reg); dwc->test_mode = false; dwc3_stop_active_transfers(dwc); @@ -2305,11 +2303,11 @@ static void dwc3_gadget_conndone_interrupt(struct dwc3 *dwc) if (dwc->has_lpm_erratum && dwc->revision >= DWC3_REVISION_240A) reg |= DWC3_DCTL_LPM_ERRATA(dwc->lpm_nyet_threshold); - dwc3_writel(dwc->regs, DWC3_DCTL, reg); + dwc3_gadget_dctl_write_safe(dwc, reg); } else { reg = dwc3_readl(dwc->regs, DWC3_DCTL); reg &= ~DWC3_DCTL_HIRD_THRES_MASK; - dwc3_writel(dwc->regs, DWC3_DCTL, reg); + dwc3_gadget_dctl_write_safe(dwc, reg); } dep = dwc->eps[0]; @@ -2417,7 +2415,7 @@ static void dwc3_gadget_linksts_change_interrupt(struct dwc3 *dwc, reg &= ~u1u2; - dwc3_writel(dwc->regs, DWC3_DCTL, reg); + dwc3_gadget_dctl_write_safe(dwc, reg); break; default: /* do nothing */ diff --git a/drivers/usb/dwc3/gadget.h b/drivers/usb/dwc3/gadget.h index f28a9755dcb..e4f5a096956 100644 --- a/drivers/usb/dwc3/gadget.h +++ b/drivers/usb/dwc3/gadget.h @@ -104,4 +104,18 @@ static inline u32 dwc3_gadget_ep_get_transfer_index(struct dwc3 *dwc, u8 number) return DWC3_DEPCMD_GET_RSC_IDX(res_id); } +/** + * dwc3_gadget_dctl_write_safe - write to DCTL safe from link state change + * @dwc: pointer to our context structure + * @value: value to write to DCTL + * + * Use this function when doing read-modify-write to DCTL. It will not + * send link state change request. + */ +static inline void dwc3_gadget_dctl_write_safe(struct dwc3 *dwc, u32 value) +{ + value &= ~DWC3_DCTL_ULSTCHNGREQ_MASK; + dwc3_writel(dwc->regs, DWC3_DCTL, value); +} + #endif /* __DRIVERS_USB_DWC3_GADGET_H */ -- 2.43.0
