tty: serial: samsung: constify variables and pointers

Constify variables, data pointed by several pointers and
"udivslot_table" static array.  This makes code a bit safer.
Tested-by: Alim Akhtar <alim.akhtar@samsung.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20220308080919.152715-8-krzysztof.kozlowski@canonical.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/samsung_tty.c

@@ -164,7 +164,7 @@ static void s3c24xx_serial_tx_chars(struct s3c24xx_uart_port *ourport);
 #define portaddrl(port, reg) \
 	((unsigned long *)(unsigned long)((port)->membase + (reg)))
 
-static u32 rd_reg(struct uart_port *port, u32 reg)
+static u32 rd_reg(const struct uart_port *port, u32 reg)
 {
 	switch (port->iotype) {
 	case UPIO_MEM:
@@ -179,7 +179,7 @@ static u32 rd_reg(struct uart_port *port, u32 reg)
 
 #define rd_regl(port, reg) (readl_relaxed(portaddr(port, reg)))
 
-static void wr_reg(struct uart_port *port, u32 reg, u32 val)
+static void wr_reg(const struct uart_port *port, u32 reg, u32 val)
 {
 	switch (port->iotype) {
 	case UPIO_MEM:
@@ -195,7 +195,7 @@ static void wr_reg(struct uart_port *port, u32 reg, u32 val)
 
 /* Byte-order aware bit setting/clearing functions. */
 
-static inline void s3c24xx_set_bit(struct uart_port *port, int idx,
+static inline void s3c24xx_set_bit(const struct uart_port *port, int idx,
 				   unsigned int reg)
 {
 	unsigned long flags;
@@ -208,7 +208,7 @@ static inline void s3c24xx_set_bit(struct uart_port *port, int idx,
 	local_irq_restore(flags);
 }
 
-static inline void s3c24xx_clear_bit(struct uart_port *port, int idx,
+static inline void s3c24xx_clear_bit(const struct uart_port *port, int idx,
 				     unsigned int reg)
 {
 	unsigned long flags;
@@ -221,19 +221,19 @@ static inline void s3c24xx_clear_bit(struct uart_port *port, int idx,
 	local_irq_restore(flags);
 }
 
-static inline struct s3c24xx_uart_port *to_ourport(const struct uart_port *port)
+static inline struct s3c24xx_uart_port *to_ourport(struct uart_port *port)
 {
 	return container_of(port, struct s3c24xx_uart_port, port);
 }
 
 /* translate a port to the device name */
 
-static inline const char *s3c24xx_serial_portname(struct uart_port *port)
+static inline const char *s3c24xx_serial_portname(const struct uart_port *port)
 {
 	return to_platform_device(port->dev)->name;
 }
 
-static int s3c24xx_serial_txempty_nofifo(struct uart_port *port)
+static int s3c24xx_serial_txempty_nofifo(const struct uart_port *port)
 {
 	return rd_regl(port, S3C2410_UTRSTAT) & S3C2410_UTRSTAT_TXE;
 }
@@ -358,7 +358,7 @@ static void s3c24xx_serial_tx_dma_complete(void *args)
 
 static void enable_tx_dma(struct s3c24xx_uart_port *ourport)
 {
-	struct uart_port *port = &ourport->port;
+	const struct uart_port *port = &ourport->port;
 	u32 ucon;
 
 	/* Mask Tx interrupt */
@@ -387,7 +387,7 @@ static void enable_tx_dma(struct s3c24xx_uart_port *ourport)
 
 static void enable_tx_pio(struct s3c24xx_uart_port *ourport)
 {
-	struct uart_port *port = &ourport->port;
+	const struct uart_port *port = &ourport->port;
 	u32 ucon, ufcon;
 
 	/* Set ufcon txtrig */
@@ -580,9 +580,9 @@ static inline const struct s3c24xx_uart_info
 }
 
 static inline const struct s3c2410_uartcfg
-	*s3c24xx_port_to_cfg(struct uart_port *port)
+	*s3c24xx_port_to_cfg(const struct uart_port *port)
 {
-	struct s3c24xx_uart_port *ourport;
+	const struct s3c24xx_uart_port *ourport;
 
 	if (port->dev == NULL)
 		return NULL;
@@ -591,7 +591,7 @@ static inline const struct s3c2410_uartcfg
 	return ourport->cfg;
 }
 
-static int s3c24xx_serial_rx_fifocnt(struct s3c24xx_uart_port *ourport,
+static int s3c24xx_serial_rx_fifocnt(const struct s3c24xx_uart_port *ourport,
 				     unsigned long ufstat)
 {
 	const struct s3c24xx_uart_info *info = ourport->info;
@@ -944,8 +944,8 @@ static irqreturn_t s3c24xx_serial_tx_irq(int irq, void *id)
 /* interrupt handler for s3c64xx and later SoC's.*/
 static irqreturn_t s3c64xx_serial_handle_irq(int irq, void *id)
 {
-	struct s3c24xx_uart_port *ourport = id;
-	struct uart_port *port = &ourport->port;
+	const struct s3c24xx_uart_port *ourport = id;
+	const struct uart_port *port = &ourport->port;
 	unsigned int pend = rd_regl(port, S3C64XX_UINTP);
 	irqreturn_t ret = IRQ_HANDLED;
 
@@ -963,8 +963,8 @@ static irqreturn_t s3c64xx_serial_handle_irq(int irq, void *id)
 /* interrupt handler for Apple SoC's.*/
 static irqreturn_t apple_serial_handle_irq(int irq, void *id)
 {
-	struct s3c24xx_uart_port *ourport = id;
-	struct uart_port *port = &ourport->port;
+	const struct s3c24xx_uart_port *ourport = id;
+	const struct uart_port *port = &ourport->port;
 	unsigned int pend = rd_regl(port, S3C2410_UTRSTAT);
 	irqreturn_t ret = IRQ_NONE;
 
@@ -1496,7 +1496,7 @@ static unsigned int s3c24xx_serial_getclk(struct s3c24xx_uart_port *ourport,
  * This table takes the fractional value of the baud divisor and gives
  * the recommended setting for the UDIVSLOT register.
  */
-static u16 udivslot_table[16] = {
+static const u16 udivslot_table[16] = {
 	[0] = 0x0000,
 	[1] = 0x0080,
 	[2] = 0x0808,
@@ -1672,7 +1672,7 @@ static void s3c24xx_serial_set_termios(struct uart_port *port,
 
 static const char *s3c24xx_serial_type(struct uart_port *port)
 {
-	struct s3c24xx_uart_port *ourport = to_ourport(port);
+	const struct s3c24xx_uart_port *ourport = to_ourport(port);
 
 	switch (ourport->info->type) {
 	case TYPE_S3C24XX:
@@ -2447,7 +2447,7 @@ s3c24xx_port_configured(unsigned int ucon)
 
 static int s3c24xx_serial_get_poll_char(struct uart_port *port)
 {
-	struct s3c24xx_uart_port *ourport = to_ourport(port);
+	const struct s3c24xx_uart_port *ourport = to_ourport(port);
 	unsigned int ufstat;
 
 	ufstat = rd_regl(port, S3C2410_UFSTAT);
@@ -2932,7 +2932,7 @@ module_exit(samsung_serial_exit);
  * Early console.
  */
 
-static void wr_reg_barrier(struct uart_port *port, u32 reg, u32 val)
+static void wr_reg_barrier(const struct uart_port *port, u32 reg, u32 val)
 {
 	switch (port->iotype) {
 	case UPIO_MEM:
@@ -2949,15 +2949,15 @@ struct samsung_early_console_data {
 	u32 rxfifo_mask;
 };
 
-static void samsung_early_busyuart(struct uart_port *port)
+static void samsung_early_busyuart(const struct uart_port *port)
 {
 	while (!(readl(port->membase + S3C2410_UTRSTAT) & S3C2410_UTRSTAT_TXFE))
 		;
 }
 
-static void samsung_early_busyuart_fifo(struct uart_port *port)
+static void samsung_early_busyuart_fifo(const struct uart_port *port)
 {
-	struct samsung_early_console_data *data = port->private_data;
+	const struct samsung_early_console_data *data = port->private_data;
 
 	while (readl(port->membase + S3C2410_UFSTAT) & data->txfull_mask)
 		;