serial:bfin-uart:Remove 'struct timeval'

The bfin-uart code uses real time with struct timeval. This will
cause problems on 32-bit architectures in 2038 when time_t
overflows.
Since the code just needs delta value of time, it is not
necessary to record them in real time.
This patch changes the code to use the monotonic time instead,
replaces struct timeval and do_gettimeofday() with u64 and
ktime_get_ns().

Signed-off-by: DengChao <chao.deng@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/bfin_uart.c b/drivers/tty/serial/bfin_uart.c
index ae3cf94b146b096fcae7dc2bcbdb795a505b4bb8..293ecbb00684cfc94b03fb231d3e92c7fb718461 100644 (file)
--- a/drivers/tty/serial/bfin_uart.c
+++ b/drivers/tty/serial/bfin_uart.c
@@ -213,7 +213,7 @@ static void bfin_serial_stop_rx(struct uart_port *port)
 static void bfin_serial_rx_chars(struct bfin_serial_port *uart)
 {
        unsigned int status, ch, flg;
-       static struct timeval anomaly_start = { .tv_sec = 0 };
+       static u64 anomaly_start;
 
        status = UART_GET_LSR(uart);
        UART_CLEAR_LSR(uart);
@@ -246,27 +246,24 @@ static void bfin_serial_rx_chars(struct bfin_serial_port *uart)
                 * character time +/- some percent.  So 1.5 sounds good.  All other
                 * Blackfin families operate properly.  Woo.
                 */
-               if (anomaly_start.tv_sec) {
-                       struct timeval curr;
-                       suseconds_t usecs;
+               if (anomaly_start > 0) {
+                       u64 curr, nsecs, threshold_ns;
 
                        if ((~ch & (~ch + 1)) & 0xff)
                                goto known_good_char;
 
-                       do_gettimeofday(&curr);
-                       if (curr.tv_sec - anomaly_start.tv_sec > 1)
+                       curr = ktime_get_ns();
+                       nsecs = curr - anomaly_start;
+                       if (nsecs >> 32)
                                goto known_good_char;
 
-                       usecs = 0;
-                       if (curr.tv_sec != anomaly_start.tv_sec)
-                               usecs += USEC_PER_SEC;
-                       usecs += curr.tv_usec - anomaly_start.tv_usec;
-
-                       if (usecs > UART_GET_ANOMALY_THRESHOLD(uart))
+                       threshold_ns = UART_GET_ANOMALY_THRESHOLD(uart)
+                                                       * NSEC_PER_USEC;
+                       if (nsecs > threshold_ns)
                                goto known_good_char;
 
                        if (ch)
-                               anomaly_start.tv_sec = 0;
+                               anomaly_start = 0;
                        else
                                anomaly_start = curr;
 
@@ -274,14 +271,14 @@ static void bfin_serial_rx_chars(struct bfin_serial_port *uart)
 
  known_good_char:
                        status &= ~BI;
-                       anomaly_start.tv_sec = 0;
+                       anomaly_start = 0;
                }
        }
 
        if (status & BI) {
                if (ANOMALY_05000363)
                        if (bfin_revid() < 5)
-                               do_gettimeofday(&anomaly_start);
+                               anomaly_start = ktime_get_ns();
                uart->port.icount.brk++;
                if (uart_handle_break(&uart->port))
                        goto ignore_char;