usb: dwc3: gadget: Don't send unintended link state change

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.

Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 154f3f3..f8f4af8 100644 (file)
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -57,7 +57,7 @@ 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;
 }
@@ -1828,7 +1828,7 @@ 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 {
                reg = dwc3_readl(dwc->regs, DWC3_DSTS);
@@ -2761,10 +2761,8 @@ 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);
 
@@ -2816,7 +2814,7 @@ 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_clear_stall_all_ep(dwc);
 
@@ -2920,11 +2918,11 @@ static void dwc3_gadget_conndone_interrupt(struct dwc3 *dwc)
                if (dwc->has_lpm_erratum && dwc->revision >= DWC3_REVISION_240A)
                        reg |= DWC3_DCTL_NYET_THRES(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];
@@ -3033,7 +3031,7 @@ 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 5faf4d1..fbc7d80 100644 (file)
--- a/drivers/usb/dwc3/gadget.h
+++ b/drivers/usb/dwc3/gadget.h
@@ -127,4 +127,18 @@ static inline void dwc3_gadget_ep_get_transfer_index(struct dwc3_ep *dep)
        dep->resource_index = 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 */