drivers: tty: serial: sb1250-duart: fill mapsize and use it

Fill the struct uart_port->mapsize field and use it, insteaf of
hardcoded values in many places. This makes the code layout a bit
more consistent and easily allows using generic helpers for the
io memory handling.

Candidates for such helpers could be eg. the request+ioremap and
iounmap+release combinations.

Signed-off-by: Enrico Weigelt <info@metux.net>

drivers/tty/serial/sb1250-duart.c

@@ -653,7 +653,7 @@ static void sbd_release_port(struct uart_port *uport)
 
 	if(refcount_dec_and_test(&duart->map_guard))
 		release_mem_region(duart->mapctrl, DUART_CHANREG_SPACING);
-	release_mem_region(uport->mapbase, DUART_CHANREG_SPACING);
+	release_mem_region(uport->mapbase, uport->mapsize);
 }
 
 static int sbd_map_port(struct uart_port *uport)
@@ -663,7 +663,7 @@ static int sbd_map_port(struct uart_port *uport)
 
 	if (!uport->membase)
 		uport->membase = ioremap(uport->mapbase,
-						 DUART_CHANREG_SPACING);
+					 uport->mapsize);
 	if (!uport->membase) {
 		dev_err(uport->dev, "Cannot map MMIO (base)\n");
 		return -ENOMEM;
@@ -688,7 +688,7 @@ static int sbd_request_port(struct uart_port *uport)
 	struct sbd_duart *duart = to_sport(uport)->duart;
 	int ret = 0;
 
-	if (!request_mem_region(uport->mapbase, DUART_CHANREG_SPACING,
+	if (!request_mem_region(uport->mapbase, uport->mapsize,
 				"sb1250-duart")) {
 		pr_err(err);
 		return -EBUSY;
@@ -711,7 +711,7 @@ static int sbd_request_port(struct uart_port *uport)
 		}
 	}
 	if (ret) {
-		release_mem_region(uport->mapbase, DUART_CHANREG_SPACING);
+		release_mem_region(uport->mapbase, uport->mapsize);
 		return ret;
 	}
 	return 0;
@@ -808,6 +808,7 @@ static void __init sbd_probe_duarts(void)
 			uport->line	= line;
 			uport->mapbase	= SBD_CHANREGS(line);
 			uport->has_sysrq = IS_ENABLED(CONFIG_SERIAL_SB1250_DUART_CONSOLE);
+			uport->mapsize	= DUART_CHANREG_SPACING;
 		}
 	}
 }