serial: 8250: Use C99 array initializer & define UART_REG_UNMAPPED

Use C99 array initializer insteads of comments and make unmapped checks
more obvious.

Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624205424.12686-5-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 3a8747ec672b3aed29b829287aa81bb67b7f1273..1311b00f8194fa2e7984ac72e00acf808f8719c8 100644 (file)
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -336,27 +336,29 @@ static void default_serial_dl_write(struct uart_8250_port *up, int value)
 
 #ifdef CONFIG_SERIAL_8250_RT288X
 
+#define UART_REG_UNMAPPED      -1
+
 /* Au1x00/RT288x UART hardware has a weird register layout */
 static const s8 au_io_in_map[8] = {
-        0,     /* UART_RX  */
-        2,     /* UART_IER */
-        3,     /* UART_IIR */
-        5,     /* UART_LCR */
-        6,     /* UART_MCR */
-        7,     /* UART_LSR */
-        8,     /* UART_MSR */
-       -1,     /* UART_SCR (unmapped) */
+       [UART_RX]       = 0,
+       [UART_IER]      = 2,
+       [UART_IIR]      = 3,
+       [UART_LCR]      = 5,
+       [UART_MCR]      = 6,
+       [UART_LSR]      = 7,
+       [UART_MSR]      = 8,
+       [UART_SCR]      = UART_REG_UNMAPPED,
 };
 
 static const s8 au_io_out_map[8] = {
-        1,     /* UART_TX  */
-        2,     /* UART_IER */
-        4,     /* UART_FCR */
-        5,     /* UART_LCR */
-        6,     /* UART_MCR */
-       -1,     /* UART_LSR (unmapped) */
-       -1,     /* UART_MSR (unmapped) */
-       -1,     /* UART_SCR (unmapped) */
+       [UART_TX]       = 1,
+       [UART_IER]      = 2,
+       [UART_FCR]      = 4,
+       [UART_LCR]      = 5,
+       [UART_MCR]      = 6,
+       [UART_LSR]      = UART_REG_UNMAPPED,
+       [UART_MSR]      = UART_REG_UNMAPPED,
+       [UART_SCR]      = UART_REG_UNMAPPED,
 };
 
 unsigned int au_serial_in(struct uart_port *p, int offset)
@@ -364,7 +366,7 @@ unsigned int au_serial_in(struct uart_port *p, int offset)
        if (offset >= ARRAY_SIZE(au_io_in_map))
                return UINT_MAX;
        offset = au_io_in_map[offset];
-       if (offset < 0)
+       if (offset == UART_REG_UNMAPPED)
                return UINT_MAX;
        return __raw_readl(p->membase + (offset << p->regshift));
 }
@@ -374,7 +376,7 @@ void au_serial_out(struct uart_port *p, int offset, int value)
        if (offset >= ARRAY_SIZE(au_io_out_map))
                return;
        offset = au_io_out_map[offset];
-       if (offset < 0)
+       if (offset == UART_REG_UNMAPPED)
                return;
        __raw_writel(value, p->membase + (offset << p->regshift));
 }