stdio: Add force parameter to stdio_deregister

In some cases we really want to move forward with a deregister, add a force
parameter to allow this, and replace the dev with a nulldev in this case.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

common/stdio.c

@@ -34,6 +34,9 @@ char *stdio_names[MAX_FILES] = { "stdin", "stdout", "stderr" };
 #define	CONFIG_SYS_DEVICE_NULLDEV	1
 #endif
 
+#ifdef	CONFIG_SYS_STDIO_DEREGISTER
+#define	CONFIG_SYS_DEVICE_NULLDEV	1
+#endif
 
 #ifdef CONFIG_SYS_DEVICE_NULLDEV
 void nulldev_putc(struct stdio_dev *dev, const char c)
@@ -172,7 +175,7 @@ int stdio_register(struct stdio_dev *dev)
  * returns 0 if success, -1 if device is assigned and 1 if devname not found
  */
 #ifdef	CONFIG_SYS_STDIO_DEREGISTER
-int stdio_deregister_dev(struct stdio_dev *dev)
+int stdio_deregister_dev(struct stdio_dev *dev, int force)
 {
 	int l;
 	struct list_head *pos;
@@ -181,6 +184,10 @@ int stdio_deregister_dev(struct stdio_dev *dev)
 	/* get stdio devices (ListRemoveItem changes the dev list) */
 	for (l=0 ; l< MAX_FILES; l++) {
 		if (stdio_devices[l] == dev) {
+			if (force) {
+				strcpy(temp_names[l], "nulldev");
+				continue;
+			}
 			/* Device is assigned -> report error */
 			return -1;
 		}
@@ -202,7 +209,7 @@ int stdio_deregister_dev(struct stdio_dev *dev)
 	return 0;
 }
 
-int stdio_deregister(const char *devname)
+int stdio_deregister(const char *devname, int force)
 {
 	struct stdio_dev *dev;
 
@@ -211,7 +218,7 @@ int stdio_deregister(const char *devname)
 	if (!dev) /* device not found */
 		return -ENODEV;
 
-	return stdio_deregister_dev(dev);
+	return stdio_deregister_dev(dev, force);
 }
 #endif	/* CONFIG_SYS_STDIO_DEREGISTER */
 

common/usb_kbd.c

@@ -550,7 +550,7 @@ int drv_usb_kbd_init(void)
 int usb_kbd_deregister(void)
 {
 #ifdef CONFIG_SYS_STDIO_DEREGISTER
-	int ret = stdio_deregister(DEVNAME);
+	int ret = stdio_deregister(DEVNAME, 0);
 	if (ret && ret != -ENODEV)
 		return ret;
 

drivers/serial/serial-uclass.c

@@ -198,7 +198,7 @@ static int serial_pre_remove(struct udevice *dev)
 #ifdef CONFIG_SYS_STDIO_DEREGISTER
 	struct serial_dev_priv *upriv = dev->uclass_priv;
 
-	if (stdio_deregister_dev(upriv->sdev))
+	if (stdio_deregister_dev(upriv->sdev), 0)
 		return -EPERM;
 #endif
 

include/stdio_dev.h

@@ -103,8 +103,8 @@ int stdio_init(void);
 
 void	stdio_print_current_devices(void);
 #ifdef CONFIG_SYS_STDIO_DEREGISTER
-int	stdio_deregister(const char *devname);
-int stdio_deregister_dev(struct stdio_dev *dev);
+int stdio_deregister(const char *devname, int force);
+int stdio_deregister_dev(struct stdio_dev *dev, int force);
 #endif
 struct list_head* stdio_get_list(void);
 struct stdio_dev* stdio_get_by_name(const char* name);