serial: omap: define and use to_uart_omap_port()

current code only works because struct uart_port
is the first member on the uart_omap_port structure.

If, for whatever reason, someone puts another
member as the first of the structure, that cast
won't work anymore. In order to be safe, let's use
a container_of() which, for now, gets optimized into
a cast anyway.

Tested-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/arm/plat-omap/include/plat/omap-serial.h

@@ -144,4 +144,6 @@ struct uart_omap_port {
 	struct work_struct	qos_work;
 };
 
+#define to_uart_omap_port(p)	((container_of((p), struct uart_omap_port, port)))
+
 #endif /* __OMAP_SERIAL_H__ */

drivers/tty/serial/omap-serial.c

@@ -142,7 +142,7 @@ static void serial_omap_stop_rxdma(struct uart_omap_port *up)
 
 static void serial_omap_enable_ms(struct uart_port *port)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct uart_omap_port *up = to_uart_omap_port(port);
 
 	dev_dbg(up->port.dev, "serial_omap_enable_ms+%d\n", up->port.line);
 
@@ -154,7 +154,7 @@ static void serial_omap_enable_ms(struct uart_port *port)
 
 static void serial_omap_stop_tx(struct uart_port *port)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct uart_omap_port *up = to_uart_omap_port(port);
 	struct omap_uart_port_info *pdata = up->pdev->dev.platform_data;
 
 	if (up->use_dma &&
@@ -187,7 +187,7 @@ static void serial_omap_stop_tx(struct uart_port *port)
 
 static void serial_omap_stop_rx(struct uart_port *port)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct uart_omap_port *up = to_uart_omap_port(port);
 
 	pm_runtime_get_sync(&up->pdev->dev);
 	if (up->use_dma)
@@ -308,7 +308,7 @@ static inline void serial_omap_enable_ier_thri(struct uart_omap_port *up)
 
 static void serial_omap_start_tx(struct uart_port *port)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct uart_omap_port *up = to_uart_omap_port(port);
 	struct omap_uart_port_info *pdata = up->pdev->dev.platform_data;
 	struct circ_buf *xmit;
 	unsigned int start;
@@ -450,7 +450,7 @@ static inline irqreturn_t serial_omap_irq(int irq, void *dev_id)
 
 static unsigned int serial_omap_tx_empty(struct uart_port *port)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct uart_omap_port *up = to_uart_omap_port(port);
 	unsigned long flags = 0;
 	unsigned int ret = 0;
 
@@ -465,7 +465,7 @@ static unsigned int serial_omap_tx_empty(struct uart_port *port)
 
 static unsigned int serial_omap_get_mctrl(struct uart_port *port)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct uart_omap_port *up = to_uart_omap_port(port);
 	unsigned int status;
 	unsigned int ret = 0;
 
@@ -488,7 +488,7 @@ static unsigned int serial_omap_get_mctrl(struct uart_port *port)
 
 static void serial_omap_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct uart_omap_port *up = to_uart_omap_port(port);
 	unsigned char mcr = 0;
 
 	dev_dbg(up->port.dev, "serial_omap_set_mctrl+%d\n", up->port.line);
@@ -522,7 +522,7 @@ static void serial_omap_set_mctrl(struct uart_port *port, unsigned int mctrl)
 
 static void serial_omap_break_ctl(struct uart_port *port, int break_state)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct uart_omap_port *up = to_uart_omap_port(port);
 	unsigned long flags = 0;
 
 	dev_dbg(up->port.dev, "serial_omap_break_ctl+%d\n", up->port.line);
@@ -539,7 +539,7 @@ static void serial_omap_break_ctl(struct uart_port *port, int break_state)
 
 static int serial_omap_startup(struct uart_port *port)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct uart_omap_port *up = to_uart_omap_port(port);
 	unsigned long flags = 0;
 	int retval;
 
@@ -617,7 +617,7 @@ static int serial_omap_startup(struct uart_port *port)
 
 static void serial_omap_shutdown(struct uart_port *port)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct uart_omap_port *up = to_uart_omap_port(port);
 	unsigned long flags = 0;
 
 	dev_dbg(up->port.dev, "serial_omap_shutdown+%d\n", up->port.line);
@@ -735,7 +735,7 @@ static void
 serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
 			struct ktermios *old)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct uart_omap_port *up = to_uart_omap_port(port);
 	unsigned char cval = 0;
 	unsigned char efr = 0;
 	unsigned long flags = 0;
@@ -946,7 +946,7 @@ static void
 serial_omap_pm(struct uart_port *port, unsigned int state,
 	       unsigned int oldstate)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct uart_omap_port *up = to_uart_omap_port(port);
 	unsigned char efr;
 
 	dev_dbg(up->port.dev, "serial_omap_pm+%d\n", up->port.line);
@@ -985,7 +985,7 @@ static int serial_omap_request_port(struct uart_port *port)
 
 static void serial_omap_config_port(struct uart_port *port, int flags)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct uart_omap_port *up = to_uart_omap_port(port);
 
 	dev_dbg(up->port.dev, "serial_omap_config_port+%d\n",
 							up->port.line);
@@ -1003,7 +1003,7 @@ serial_omap_verify_port(struct uart_port *port, struct serial_struct *ser)
 static const char *
 serial_omap_type(struct uart_port *port)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct uart_omap_port *up = to_uart_omap_port(port);
 
 	dev_dbg(up->port.dev, "serial_omap_type+%d\n", up->port.line);
 	return up->name;
@@ -1046,7 +1046,7 @@ static inline void wait_for_xmitr(struct uart_omap_port *up)
 
 static void serial_omap_poll_put_char(struct uart_port *port, unsigned char ch)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct uart_omap_port *up = to_uart_omap_port(port);
 
 	pm_runtime_get_sync(&up->pdev->dev);
 	wait_for_xmitr(up);
@@ -1056,7 +1056,7 @@ static void serial_omap_poll_put_char(struct uart_port *port, unsigned char ch)
 
 static int serial_omap_poll_get_char(struct uart_port *port)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct uart_omap_port *up = to_uart_omap_port(port);
 	unsigned int status;
 
 	pm_runtime_get_sync(&up->pdev->dev);
@@ -1079,7 +1079,7 @@ static struct uart_driver serial_omap_reg;
 
 static void serial_omap_console_putchar(struct uart_port *port, int ch)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)port;
+	struct uart_omap_port *up = to_uart_omap_port(port);
 
 	wait_for_xmitr(up);
 	serial_out(up, UART_TX, ch);
@@ -1355,7 +1355,7 @@ static void serial_omap_continue_tx(struct uart_omap_port *up)
 
 static void uart_tx_dma_callback(int lch, u16 ch_status, void *data)
 {
-	struct uart_omap_port *up = (struct uart_omap_port *)data;
+	struct uart_omap_port *up = data;
 	struct circ_buf *xmit = &up->port.state->xmit;
 
 	xmit->tail = (xmit->tail + up->uart_dma.tx_buf_size) & \