xhci: debugfs: add debugfs interface to enable compliance mode for a port

Enable compliance transition for a port by writing "compliance" to the
ports portsc file in debugfs.
port must be "Not-connected" and Link must be in RxDetect state to enable
compliance mode.

Only needed for host that have CTC flag set.
Allows state transitioning to compliance at 1st LFPS timeout.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-debugfs.c b/drivers/usb/host/xhci-debugfs.c
index 76e446a..cadc013 100644 (file)
--- a/drivers/usb/host/xhci-debugfs.c
+++ b/drivers/usb/host/xhci-debugfs.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/slab.h>
+#include <linux/uaccess.h>
 
 #include "xhci.h"
 #include "xhci-debugfs.h"
@@ -351,8 +352,44 @@ static int xhci_port_open(struct inode *inode, struct file *file)
        return single_open(file, xhci_portsc_show, inode->i_private);
 }
 
+static ssize_t xhci_port_write(struct file *file,  const char __user *ubuf,
+                              size_t count, loff_t *ppos)
+{
+       struct seq_file         *s = file->private_data;
+       struct xhci_port        *port = s->private;
+       struct xhci_hcd         *xhci = hcd_to_xhci(port->rhub->hcd);
+       char                    buf[32];
+       u32                     portsc;
+       unsigned long           flags;
+
+       if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
+               return -EFAULT;
+
+       if (!strncmp(buf, "compliance", 10)) {
+               /* If CTC is clear, compliance is enabled by default */
+               if (!HCC2_CTC(xhci->hcc_params2))
+                       return count;
+               spin_lock_irqsave(&xhci->lock, flags);
+               /* compliance mode can only be enabled on ports in RxDetect */
+               portsc = readl(port->addr);
+               if ((portsc & PORT_PLS_MASK) != XDEV_RXDETECT) {
+                       spin_unlock_irqrestore(&xhci->lock, flags);
+                       return -EPERM;
+               }
+               portsc = xhci_port_state_to_neutral(portsc);
+               portsc &= ~PORT_PLS_MASK;
+               portsc |= PORT_LINK_STROBE | XDEV_COMP_MODE;
+               writel(portsc, port->addr);
+               spin_unlock_irqrestore(&xhci->lock, flags);
+       } else {
+               return -EINVAL;
+       }
+       return count;
+}
+
 static const struct file_operations port_fops = {
        .open                   = xhci_port_open,
+       .write                  = xhci_port_write,
        .read                   = seq_read,
        .llseek                 = seq_lseek,
        .release                = single_release,
@@ -491,7 +528,7 @@ static void xhci_debugfs_create_ports(struct xhci_hcd *xhci,
                          num_ports + 1);
                dir = debugfs_create_dir(port_name, parent);
                port = &xhci->hw_ports[num_ports];
-               debugfs_create_file("portsc", 0444, dir, port, &port_fops);
+               debugfs_create_file("portsc", 0644, dir, port, &port_fops);
        }
 }