[PATCH v2 4/5] usb: dwc3: debugfs: Properly print/set link state for HS

[Thinh Nguyen <thinh.nguyen@xxxxxxxxxxxx>]

Highspeed device and below has different state names than superspeed and
higher. Add proper checks and printouts of link states for highspeed and
below.

Signed-off-by: Thinh Nguyen <thinhn@xxxxxxxxxxxx>
---
Change in v2:
 - New patch, no previous change

 drivers/usb/dwc3/debug.h   | 29 +++++++++++++++++++++++++++++
 drivers/usb/dwc3/debugfs.c | 19 +++++++++++++++++--
 2 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/debug.h b/drivers/usb/dwc3/debug.h
index c66d216dcc30..4f75ab3505b7 100644
--- a/drivers/usb/dwc3/debug.h
+++ b/drivers/usb/dwc3/debug.h
@@ -116,6 +116,35 @@ dwc3_gadget_link_string(enum dwc3_link_state link_state)
 	}
 }
 
+/**
+ * dwc3_gadget_hs_link_string - returns highspeed and below link name
+ * @link_state: link state code
+ */
+static inline const char *
+dwc3_gadget_hs_link_string(enum dwc3_link_state link_state)
+{
+	switch (link_state) {
+	case DWC3_LINK_STATE_U0:
+		return "On";
+	case DWC3_LINK_STATE_U2:
+		return "Sleep";
+	case DWC3_LINK_STATE_U3:
+		return "Suspend";
+	case DWC3_LINK_STATE_SS_DIS:
+		return "Disconnected";
+	case DWC3_LINK_STATE_RX_DET:
+		return "Early Suspend";
+	case DWC3_LINK_STATE_RECOV:
+		return "Recovery";
+	case DWC3_LINK_STATE_RESET:
+		return "Reset";
+	case DWC3_LINK_STATE_RESUME:
+		return "Resume";
+	default:
+		return "UNKNOWN link state\n";
+	}
+}
+
 /**
  * dwc3_trb_type_string - returns TRB type as a string
  * @type: the type of the TRB
diff --git a/drivers/usb/dwc3/debugfs.c b/drivers/usb/dwc3/debugfs.c
index 1da012f105d7..e613a61ae58a 100644
--- a/drivers/usb/dwc3/debugfs.c
+++ b/drivers/usb/dwc3/debugfs.c
@@ -539,13 +539,17 @@ static int dwc3_link_state_show(struct seq_file *s, void *unused)
 	unsigned long		flags;
 	enum dwc3_link_state	state;
 	u32			reg;
+	u8			speed;
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	reg = dwc3_readl(dwc->regs, DWC3_DSTS);
 	state = DWC3_DSTS_USBLNKST(reg);
-	spin_unlock_irqrestore(&dwc->lock, flags);
+	speed = reg & DWC3_DSTS_CONNECTSPD;
 
-	seq_printf(s, "%s\n", dwc3_gadget_link_string(state));
+	seq_printf(s, "%s\n", (speed >= DWC3_DSTS_SUPERSPEED) ?
+		   dwc3_gadget_link_string(state) :
+		   dwc3_gadget_hs_link_string(state));
+	spin_unlock_irqrestore(&dwc->lock, flags);
 
 	return 0;
 }
@@ -563,6 +567,8 @@ static ssize_t dwc3_link_state_write(struct file *file,
 	unsigned long		flags;
 	enum dwc3_link_state	state = 0;
 	char			buf[32];
+	u32			reg;
+	u8			speed;
 
 	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
 		return -EFAULT;
@@ -583,6 +589,15 @@ static ssize_t dwc3_link_state_write(struct file *file,
 		return -EINVAL;
 
 	spin_lock_irqsave(&dwc->lock, flags);
+	reg = dwc3_readl(dwc->regs, DWC3_DSTS);
+	speed = reg & DWC3_DSTS_CONNECTSPD;
+
+	if (speed < DWC3_DSTS_SUPERSPEED &&
+	    state != DWC3_LINK_STATE_RECOV) {
+		spin_unlock_irqrestore(&dwc->lock, flags);
+		return -EINVAL;
+	}
+
 	dwc3_gadget_set_link_state(dwc, state);
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
-- 
2.11.0