xhci: debugfs: add usb ports to xhci debugfs

Add ports/portxx/portsc for each xHC hardware usb port to debugfs.
Showing the content of the port status and control register for
each port (PORTSC)

Portxx is numbered starting from 1 for historical reasons to better
match port numbering shown by lsusb and other places.

Ports in debugfs are in the order XHC controller has them,
In most cases USB2 ports come first, followed by USB3 ports.
i.e. USB2 ports are port01-portxx, and USB3 portxx-portmax.

Signed-off-by: Mathias Nyman <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/host/xhci-debugfs.c

···
 	.release		= single_release,
 };
 
+
+
+static int xhci_portsc_show(struct seq_file *s, void *unused)
+{
+	struct xhci_port	*port = s->private;
+	u32			portsc;
+
+	portsc = readl(port->addr);
+	seq_printf(s, "%s\n", xhci_decode_portsc(portsc));
+
+	return 0;
+}
+
+static int xhci_port_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, xhci_portsc_show, inode->i_private);
+}
+
+static const struct file_operations port_fops = {
+	.open			= xhci_port_open,
+	.read			= seq_read,
+	.llseek			= seq_lseek,
+	.release		= single_release,
+};
+
 static void xhci_debugfs_create_files(struct xhci_hcd *xhci,
 				      struct xhci_file_map *files,
 				      size_t nentries, void *data,
···
 	dev->debugfs_private = NULL;
 }
 
+static void xhci_debugfs_create_ports(struct xhci_hcd *xhci,
+				      struct dentry *parent)
+{
+	unsigned int		num_ports;
+	char			port_name[8];
+	struct xhci_port	*port;
+	struct dentry		*dir;
+
+	num_ports = HCS_MAX_PORTS(xhci->hcs_params1);
+
+	parent = debugfs_create_dir("ports", parent);
+
+	while (num_ports--) {
+		scnprintf(port_name, sizeof(port_name), "port%02d",
+			  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);
+	}
+}
+
 void xhci_debugfs_init(struct xhci_hcd *xhci)
 {
 	struct device		*dev = xhci_to_hcd(xhci)->self.controller;
···
 				     xhci->debugfs_root);
 
 	xhci->debugfs_slots = debugfs_create_dir("devices", xhci->debugfs_root);
+
+	xhci_debugfs_create_ports(xhci, xhci->debugfs_root);
 }
 
 void xhci_debugfs_exit(struct xhci_hcd *xhci)