1 files changed, 17 insertions, 10 deletions

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index d58783d364e3..dacf0a09ab24 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -318,7 +318,7 @@ static void pl011_dma_probe_initcall(struct device *dev, struct uart_amba_port *
 			.src_addr = uap->port.mapbase + UART01x_DR,
 			.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
 			.direction = DMA_DEV_TO_MEM,
-			.src_maxburst = uap->fifosize >> 1,
+			.src_maxburst = uap->fifosize >> 2,
 			.device_fc = false,
 		};
 
@@ -2154,9 +2154,19 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
 	amba_ports[i] = uap;
 
 	amba_set_drvdata(dev, uap);
+
+	if (!amba_reg.state) {
+		ret = uart_register_driver(&amba_reg);
+		if (ret < 0) {
+			pr_err("Failed to register AMBA-PL011 driver\n");
+			return ret;
+		}
+	}
+
 	ret = uart_add_one_port(&amba_reg, &uap->port);
 	if (ret) {
 		amba_ports[i] = NULL;
+		uart_unregister_driver(&amba_reg);
 		pl011_dma_remove(uap);
 	}
  out:
@@ -2166,6 +2176,7 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
 static int pl011_remove(struct amba_device *dev)
 {
 	struct uart_amba_port *uap = amba_get_drvdata(dev);
+	bool busy = false;
 	int i;
 
 	uart_remove_one_port(&amba_reg, &uap->port);
@@ -2173,8 +2184,12 @@ static int pl011_remove(struct amba_device *dev)
 	for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
 		if (amba_ports[i] == uap)
 			amba_ports[i] = NULL;
+		else if (amba_ports[i])
+			busy = true;
 
 	pl011_dma_remove(uap);
+	if (!busy)
+		uart_unregister_driver(&amba_reg);
 	return 0;
 }
 
@@ -2230,22 +2245,14 @@ static struct amba_driver pl011_driver = {
 
 static int __init pl011_init(void)
 {
-	int ret;
 	printk(KERN_INFO "Serial: AMBA PL011 UART driver\n");
 
-	ret = uart_register_driver(&amba_reg);
-	if (ret == 0) {
-		ret = amba_driver_register(&pl011_driver);
-		if (ret)
-			uart_unregister_driver(&amba_reg);
-	}
-	return ret;
+	return amba_driver_register(&pl011_driver);
 }
 
 static void __exit pl011_exit(void)
 {
 	amba_driver_unregister(&pl011_driver);
-	uart_unregister_driver(&amba_reg);
 }
 
 /*