xhci: dbc: create and remove dbc structure in dbgtty driver.

Turn the dbgtty closer to a device driver by allocating the dbc
structure in its own xhci_dbc_tty_probe() function, and freeing it
in xhci_dbc_tty_remove()

Remove xhci_do_dbc_exit() as its no longer needed.

allocate and create the dbc strcuture in xhci_dbc_tty_probe()
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20220216095153.1303105-3-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-dbgcap.c

@@ -914,16 +914,6 @@ static void xhci_dbc_handle_events(struct work_struct *work)
 	mod_delayed_work(system_wq, &dbc->event_work, 1);
 }
 
-static void xhci_do_dbc_exit(struct xhci_hcd *xhci)
-{
-	unsigned long		flags;
-
-	spin_lock_irqsave(&xhci->lock, flags);
-	kfree(xhci->dbc);
-	xhci->dbc = NULL;
-	spin_unlock_irqrestore(&xhci->lock, flags);
-}
-
 static ssize_t dbc_show(struct device *dev,
 			struct device_attribute *attr,
 			char *buf)
@@ -984,7 +974,7 @@ static ssize_t dbc_store(struct device *dev,
 static DEVICE_ATTR_RW(dbc);
 
 struct xhci_dbc *
-xhci_alloc_dbc(struct device *dev, void __iomem *base)
+xhci_alloc_dbc(struct device *dev, void __iomem *base, const struct dbc_driver *driver)
 {
 	struct xhci_dbc		*dbc;
 	int			ret;
@@ -995,6 +985,7 @@ xhci_alloc_dbc(struct device *dev, void __iomem *base)
 
 	dbc->regs = base;
 	dbc->dev = dev;
+	dbc->driver = driver;
 
 	if (readl(&dbc->regs->control) & DBC_CTRL_DBC_ENABLE)
 		return NULL;
@@ -1045,18 +1036,8 @@ int xhci_dbc_init(struct xhci_hcd *xhci)
 	if (xhci->dbc)
 		return -EBUSY;
 
-	xhci->dbc = xhci_alloc_dbc(dev, base);
-	if (!xhci->dbc)
-		return -ENOMEM;
-
-	ret = xhci_dbc_tty_probe(xhci);
-	if (ret)
-		goto init_err2;
-
-	return 0;
+	ret = xhci_dbc_tty_probe(dev, base + dbc_cap_offs, xhci);
 
-init_err2:
-	xhci_do_dbc_exit(xhci);
 	return ret;
 }
 
@@ -1068,7 +1049,6 @@ void xhci_dbc_exit(struct xhci_hcd *xhci)
 		return;
 
 	xhci_dbc_tty_remove(xhci->dbc);
-	xhci_dbc_remove(xhci->dbc);
 	spin_lock_irqsave(&xhci->lock, flags);
 	xhci->dbc = NULL;
 	spin_unlock_irqrestore(&xhci->lock, flags);

drivers/usb/host/xhci-dbgcap.h

@@ -196,8 +196,11 @@ static inline struct dbc_ep *get_out_ep(struct xhci_dbc *dbc)
 #ifdef CONFIG_USB_XHCI_DBGCAP
 int xhci_dbc_init(struct xhci_hcd *xhci);
 void xhci_dbc_exit(struct xhci_hcd *xhci);
-int xhci_dbc_tty_probe(struct xhci_hcd *xhci);
+int xhci_dbc_tty_probe(struct device *dev, void __iomem *res, struct xhci_hcd *xhci);
 void xhci_dbc_tty_remove(struct xhci_dbc *dbc);
+struct xhci_dbc *xhci_alloc_dbc(struct device *dev, void __iomem *res,
+				 const struct dbc_driver *driver);
+void xhci_dbc_remove(struct xhci_dbc *dbc);
 struct dbc_request *dbc_alloc_request(struct xhci_dbc *dbc,
 				      unsigned int direction,
 				      gfp_t flags);

drivers/usb/host/xhci-dbgtty.c

@@ -468,9 +468,9 @@ static const struct dbc_driver dbc_driver = {
 	.disconnect		= xhci_dbc_tty_unregister_device,
 };
 
-int xhci_dbc_tty_probe(struct xhci_hcd *xhci)
+int xhci_dbc_tty_probe(struct device *dev, void __iomem *base, struct xhci_hcd *xhci)
 {
-	struct xhci_dbc		*dbc = xhci->dbc;
+	struct xhci_dbc		*dbc;
 	struct dbc_port		*port;
 	int			status;
 
@@ -485,13 +485,22 @@ int xhci_dbc_tty_probe(struct xhci_hcd *xhci)
 		goto out;
 	}
 
-	dbc->driver = &dbc_driver;
-	dbc->priv = port;
+	dbc_tty_driver->driver_state = port;
+
+	dbc = xhci_alloc_dbc(dev, base, &dbc_driver);
+	if (!dbc) {
+		status = -ENOMEM;
+		goto out2;
+	}
 
+	dbc->priv = port;
 
-	dbc_tty_driver->driver_state = port;
+	/* get rid of xhci once this is a real driver binding to a device */
+	xhci->dbc = dbc;
 
 	return 0;
+out2:
+	kfree(port);
 out:
 	/* dbc_tty_exit will be called by module_exit() in the future */
 	dbc_tty_exit();
@@ -506,8 +515,7 @@ void xhci_dbc_tty_remove(struct xhci_dbc *dbc)
 {
 	struct dbc_port         *port = dbc_to_port(dbc);
 
-	dbc->driver = NULL;
-	dbc->priv = NULL;
+	xhci_dbc_remove(dbc);
 	kfree(port);
 
 	/* dbc_tty_exit will be called by  module_exit() in the future */