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usb: gadget: Link state changes

PATCH Superseded Thinh Nguyen 2 participants 7 messages Oct 22, 2019 – Oct 24, 2019

Subsystems (2)
USB DesignWare USB3 DRD IP driver

v1 of 2 Superseded Latest is v2 →

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Thinh Nguyen

author maintainer
#0 lore raw

cover usb: gadget: Link state changes

This patch series adds some fixes to how dwc3 handles cases related to link state changes.

Thinh Nguyen (4):
usb: dwc3: gadget: Don't send unintended link state change
usb: dwc3: gadget: Set link state to RX_Detect on disconnect
usb: dwc3: gadget: Clear DCTL.ULSTCHNGREQ before set
usb: dwc3: debug: Remove newline printout

 drivers/usb/dwc3/debug.h  |  4 ++--
 drivers/usb/dwc3/gadget.c | 26 ++++++++++++++++++++++++++
 2 files changed, 28 insertions(+), 2 deletions(-)
Signature · 1 line
2.11.0
author maintainer
#1 lore raw

PATCH 1/4 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 <[email protected]>
---
 drivers/usb/dwc3/gadget.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
drivers/usb/dwc3/gadget.c +21 -0
index 86dc1db788a9..24178b4b9d46 100644
@@ -57,6 +57,8 @@ int dwc3_gadget_set_test_mode(struct dwc3 *dwc, int mode)
 		return -EINVAL;
 	}
 
+	/* Don't send link state change request */
+	reg &= ~DWC3_DCTL_ULSTCHNGREQ_MASK;
 	dwc3_writel(dwc->regs, DWC3_DCTL, reg);
 
 	return 0;

@@ -1822,6 +1824,9 @@ static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on, int suspend)
 		dwc->pullups_connected = false;
 	}
 
+	/* Don't send link state change request */
+	reg &= ~DWC3_DCTL_ULSTCHNGREQ_MASK;
+
 	dwc3_writel(dwc->regs, DWC3_DCTL, reg);
 
 	do {

@@ -2744,6 +2749,10 @@ static void dwc3_gadget_disconnect_interrupt(struct dwc3 *dwc)
 	int			reg;
 
 	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
+
+	/* Don't send link state change request */
+	reg &= ~DWC3_DCTL_ULSTCHNGREQ_MASK;
+
 	reg &= ~DWC3_DCTL_INITU1ENA;
 	dwc3_writel(dwc->regs, DWC3_DCTL, reg);
 

@@ -2799,6 +2808,10 @@ static void dwc3_gadget_reset_interrupt(struct dwc3 *dwc)
 	dwc3_reset_gadget(dwc);
 
 	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
+
+	/* Don't send link state change request */
+	reg &= ~DWC3_DCTL_ULSTCHNGREQ_MASK;
+
 	reg &= ~DWC3_DCTL_TSTCTRL_MASK;
 	dwc3_writel(dwc->regs, DWC3_DCTL, reg);
 	dwc->test_mode = false;

@@ -2904,10 +2917,15 @@ 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);
 
+		/* Don't send link state change request */
+		reg &= ~DWC3_DCTL_ULSTCHNGREQ_MASK;
 		dwc3_writel(dwc->regs, DWC3_DCTL, reg);
 	} else {
 		reg = dwc3_readl(dwc->regs, DWC3_DCTL);
 		reg &= ~DWC3_DCTL_HIRD_THRES_MASK;
+
+		/* Don't send link state change request */
+		reg &= ~DWC3_DCTL_ULSTCHNGREQ_MASK;
 		dwc3_writel(dwc->regs, DWC3_DCTL, reg);
 	}
 

@@ -3017,6 +3035,9 @@ static void dwc3_gadget_linksts_change_interrupt(struct dwc3 *dwc,
 
 				reg &= ~u1u2;
 
+				/* Don't send link state change request */
+				reg &= ~DWC3_DCTL_ULSTCHNGREQ_MASK;
+
 				dwc3_writel(dwc->regs, DWC3_DCTL, reg);
 				break;
 			default:
Signature · 1 line
2.11.0
#2 lore raw

Re: [PATCH 1/4] usb: dwc3: gadget: Don't send unintended link state change

Hi Thinh,

Quoted 6 lines · Thinh Nguyen

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 <[email protected]>

WHAT A GREAT CATCH!!! However, let's do one small change here:

Quoted 9 lines
---
 drivers/usb/dwc3/gadget.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
drivers/usb/dwc3/gadget.c +0 -0
index 86dc1db788a9..24178b4b9d46 100644

drivers/usb/dwc3/gadget.c int dwc3_gadget_set_test_mode(struct dwc3 *dwc, int mode) · line 62

Quoted 6 lines
drivers/usb/dwc3/gadget.c +2 -0
@@ -57,6 +57,8 @@ int dwc3_gadget_set_test_mode(struct dwc3 *dwc, int mode)
 		return -EINVAL;
 	}
 
+	/* Don't send link state change request */
+	reg &= ~DWC3_DCTL_ULSTCHNGREQ_MASK;
 	dwc3_writel(dwc->regs, DWC3_DCTL, reg);

Let's a small macro or a little function to wrap this. Something dwc3_dctl_write_safe() or something long those line.

Then that macro/function will make sure to clear those bits.

Signature · 1 line
balbi
author maintainer
#3 lore raw

Re: [PATCH 1/4] usb: dwc3: gadget: Don't send unintended link state change

Hi,

Quoted 21 lines · Felipe Balbi
Quoted 6 lines · Thinh Nguyen

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 <[email protected]>

WHAT A GREAT CATCH!!! However, let's do one small change here:

Quoted 12 lines
---
  drivers/usb/dwc3/gadget.c | 21 +++++++++++++++++++++
  1 file changed, 21 insertions(+)
drivers/usb/dwc3/gadget.c +0 -0
index 86dc1db788a9..24178b4b9d46 100644
@@ -57,6 +57,8 @@ int dwc3_gadget_set_test_mode(struct dwc3 *dwc, int mode)
  		return -EINVAL;
  	}
Quoted 7 lines

drivers/usb/dwc3/gadget.c int dwc3_gadget_set_test_mode(struct dwc3 *dwc, int mode) · line 62

Quoted 3 lines
drivers/usb/dwc3/gadget.c +2 -0
+	/* Don't send link state change request */
+	reg &= ~DWC3_DCTL_ULSTCHNGREQ_MASK;
  	dwc3_writel(dwc->regs, DWC3_DCTL, reg);

Let's a small macro or a little function to wrap this. Something dwc3_dctl_write_safe() or something long those line.

Then that macro/function will make sure to clear those bits.

Sure. I'll resend with the change.

Thanks,
Thinh

author maintainer
#4 lore raw

PATCH 2/4 usb: dwc3: gadget: Set link state to RX_Detect on disconnect

In reply to Thinh Nguyen

When DWC3 receives disconnect event, it needs to set the link state to RX_Detect.

DWC_usb3 3.30a programming guide 4.1.7

Signed-off-by Thinh Nguyen <[email protected]>
---
 drivers/usb/dwc3/gadget.c | 2 ++
 1 file changed, 2 insertions(+)
drivers/usb/dwc3/gadget.c +2 -0
index 24178b4b9d46..37631d2e2a2e 100644
@@ -2748,6 +2748,8 @@ static void dwc3_gadget_disconnect_interrupt(struct dwc3 *dwc)
 {
 	int			reg;
 
+	dwc3_gadget_set_link_state(dwc, DWC3_LINK_STATE_RX_DET);
+
 	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
 
 	/* Don't send link state change request */
Signature · 1 line
2.11.0
author maintainer
#5 lore raw

PATCH 3/4 usb: dwc3: gadget: Clear DCTL.ULSTCHNGREQ before set

In reply to Thinh Nguyen

Send a no-action link state change request before the actual request so DWC3 can send the same request whenever we call dwc3_gadget_set_link_state().

Signed-off-by Thinh Nguyen <[email protected]>
---
 drivers/usb/dwc3/gadget.c | 3 +++
 1 file changed, 3 insertions(+)
drivers/usb/dwc3/gadget.c +3 -0
index 37631d2e2a2e..03d58254d1e6 100644
@@ -113,6 +113,9 @@ int dwc3_gadget_set_link_state(struct dwc3 *dwc, enum dwc3_link_state state)
 	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
 	reg &= ~DWC3_DCTL_ULSTCHNGREQ_MASK;
 
+	/* set no action before sending new link state change */
+	dwc3_writel(dwc->regs, DWC3_DCTL, reg);
+
 	/* set requested state */
 	reg |= DWC3_DCTL_ULSTCHNGREQ(state);
 	dwc3_writel(dwc->regs, DWC3_DCTL, reg);
Signature · 1 line
2.11.0
author maintainer
#6 lore raw

PATCH 4/4 usb: dwc3: debug: Remove newline printout

In reply to Thinh Nguyen

The newline from the unknown link state tracepoint doesn't follow the other tracepoints, and it looks unsightly. Let's remove it.

Signed-off-by Thinh Nguyen <[email protected]>
---
 drivers/usb/dwc3/debug.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/usb/dwc3/debug.h +2 -2
index 9baabed87d61..e56beb9d1e36 100644
@@ -112,7 +112,7 @@ dwc3_gadget_link_string(enum dwc3_link_state link_state)
 	case DWC3_LINK_STATE_RESUME:
 		return "Resume";
 	default:
-		return "UNKNOWN link state\n";
+		return "UNKNOWN link state";
 	}
 }
 

@@ -141,7 +141,7 @@ dwc3_gadget_hs_link_string(enum dwc3_link_state link_state)
 	case DWC3_LINK_STATE_RESUME:
 		return "Resume";
 	default:
-		return "UNKNOWN link state\n";
+		return "UNKNOWN link state";
 	}
 }
Signature · 1 line
2.11.0