tty: cpm_uart: use resource_size()

Use the resource_size function instead of manually calculating the
resource size.  This reduces the chance of introducing off-by-one errors.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Kumar Gala <galak@gate.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/serial/cpm_uart/cpm_uart_cpm2.c b/drivers/serial/cpm_uart/cpm_uart_cpm2.c
index a9802e76b5fa..722eac18f382 100644
--- a/drivers/serial/cpm_uart/cpm_uart_cpm2.c
+++ b/drivers/serial/cpm_uart/cpm_uart_cpm2.c
@@ -61,7 +61,7 @@ void __iomem *cpm_uart_map_pram(struct uart_cpm_port *port,
         void __iomem *pram;
         unsigned long offset;
         struct resource res;
-        unsigned long len;
+        resource_size_t len;
 
         /* Don't remap parameter RAM if it has already been initialized
          * during console setup.
@@ -74,7 +74,7 @@ void __iomem *cpm_uart_map_pram(struct uart_cpm_port *port,
         if (of_address_to_resource(np, 1, &res))
                 return NULL;
 
-        len = 1 + res.end - res.start;
+        len = resource_size(&res);
         pram = ioremap(res.start, len);
         if (!pram)
                 return NULL;