usb: dwc3: gadget: allow Link state changes via debugfs

This is very useful for low level link testing where
we might not have a USB Host stack, only a scope to
verify signal integrity.

Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 110 insertions, 0 deletions

diff --git a/drivers/usb/dwc3/debugfs.c b/drivers/usb/dwc3/debugfs.c
index c7e85024fda8..a2c1cc64b48d 100644
--- a/drivers/usb/dwc3/debugfs.c
+++ b/drivers/usb/dwc3/debugfs.c
@@ -549,6 +549,109 @@ static const struct file_operations dwc3_testmode_fops = {
         .release                = single_release,
 };
 
+static int dwc3_link_state_show(struct seq_file *s, void *unused)
+{
+        struct dwc3             *dwc = s->private;
+        unsigned long           flags;
+        enum dwc3_link_state    state;
+        u32                     reg;
+
+        spin_lock_irqsave(&dwc->lock, flags);
+        reg = dwc3_readl(dwc->regs, DWC3_DSTS);
+        state = DWC3_DSTS_USBLNKST(reg);
+        spin_unlock_irqrestore(&dwc->lock, flags);
+
+        switch (state) {
+        case DWC3_LINK_STATE_U0:
+                seq_printf(s, "U0\n");
+                break;
+        case DWC3_LINK_STATE_U1:
+                seq_printf(s, "U1\n");
+                break;
+        case DWC3_LINK_STATE_U2:
+                seq_printf(s, "U2\n");
+                break;
+        case DWC3_LINK_STATE_U3:
+                seq_printf(s, "U3\n");
+                break;
+        case DWC3_LINK_STATE_SS_DIS:
+                seq_printf(s, "SS.Disabled\n");
+                break;
+        case DWC3_LINK_STATE_RX_DET:
+                seq_printf(s, "Rx.Detect\n");
+                break;
+        case DWC3_LINK_STATE_SS_INACT:
+                seq_printf(s, "SS.Inactive\n");
+                break;
+        case DWC3_LINK_STATE_POLL:
+                seq_printf(s, "Poll\n");
+                break;
+        case DWC3_LINK_STATE_RECOV:
+                seq_printf(s, "Recovery\n");
+                break;
+        case DWC3_LINK_STATE_HRESET:
+                seq_printf(s, "HRESET\n");
+                break;
+        case DWC3_LINK_STATE_CMPLY:
+                seq_printf(s, "Compliance\n");
+                break;
+        case DWC3_LINK_STATE_LPBK:
+                seq_printf(s, "Loopback\n");
+                break;
+        default:
+                seq_printf(s, "UNKNOWN %d\n", reg);
+        }
+
+        return 0;
+}
+
+static int dwc3_link_state_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, dwc3_link_state_show, inode->i_private);
+}
+
+static ssize_t dwc3_link_state_write(struct file *file,
+                const char __user *ubuf, size_t count, loff_t *ppos)
+{
+        struct seq_file         *s = file->private_data;
+        struct dwc3             *dwc = s->private;
+        unsigned long           flags;
+        enum dwc3_link_state    state = 0;
+        char                    buf[32];
+
+        if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
+                return -EFAULT;
+
+        if (!strncmp(buf, "SS.Disabled", 11))
+                state = DWC3_LINK_STATE_SS_DIS;
+        else if (!strncmp(buf, "Rx.Detect", 9))
+                state = DWC3_LINK_STATE_RX_DET;
+        else if (!strncmp(buf, "SS.Inactive", 11))
+                state = DWC3_LINK_STATE_SS_INACT;
+        else if (!strncmp(buf, "Recovery", 8))
+                state = DWC3_LINK_STATE_RECOV;
+        else if (!strncmp(buf, "Compliance", 10))
+                state = DWC3_LINK_STATE_CMPLY;
+        else if (!strncmp(buf, "Loopback", 8))
+                state = DWC3_LINK_STATE_LPBK;
+        else
+                return -EINVAL;
+
+        spin_lock_irqsave(&dwc->lock, flags);
+        dwc3_gadget_set_link_state(dwc, state);
+        spin_unlock_irqrestore(&dwc->lock, flags);
+
+        return count;
+}
+
+static const struct file_operations dwc3_link_state_fops = {
+        .open                   = dwc3_link_state_open,
+        .write                  = dwc3_link_state_write,
+        .read                   = seq_read,
+        .llseek                 = seq_lseek,
+        .release                = single_release,
+};
+
 int __devinit dwc3_debugfs_init(struct dwc3 *dwc)
 {
         struct dentry           *root;
@@ -584,6 +687,13 @@ int __devinit dwc3_debugfs_init(struct dwc3 *dwc)
                 goto err1;
         }
 
+        file = debugfs_create_file("link_state", S_IRUGO | S_IWUSR, root,
+                        dwc, &dwc3_link_state_fops);
+        if (IS_ERR(file)) {
+                ret = PTR_ERR(file);
+                goto err1;
+        }
+
         return 0;
 
 err1: