aboutsummaryrefslogtreecommitdiff
path: root/libbb/speed_table.c
diff options
context:
space:
mode:
authorGravatar Denys Vlasenko <vda.linux@googlemail.com>2016-09-26 14:37:12 +0200
committerGravatar Denys Vlasenko <vda.linux@googlemail.com>2016-09-26 14:37:12 +0200
commit525209ac9465f37a9ba292f1ff138dd80768e869 (patch)
tree741d9bef9fd62960e7a7b853bbf7cd98ba2aba40 /libbb/speed_table.c
parent4537f83d522086bec8aaa2077f889d8c1c389862 (diff)
downloadbusybox-525209ac9465f37a9ba292f1ff138dd80768e869.tar.gz
busybox-525209ac9465f37a9ba292f1ff138dd80768e869.tar.bz2
libbb/speed_table.c: expand comments
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'libbb/speed_table.c')
-rw-r--r--libbb/speed_table.c17
1 files changed, 16 insertions, 1 deletions
diff --git a/libbb/speed_table.c b/libbb/speed_table.c
index 13dc9c73a..11ced01d0 100644
--- a/libbb/speed_table.c
+++ b/libbb/speed_table.c
@@ -103,8 +103,23 @@ static const struct speed_map speeds[] = {
{B4000000, 4000000/200 + 0x8000u},
#endif
/* 4000000/200 = 0x4e20, bit#15 still does not interfere with the value */
+/* (can use /800 if higher speeds would appear, /1600 won't work for B500000) */
};
+/*
+ * TODO: maybe we can just bite the bullet, ditch the table and use termios2
+ * Linux API (supports arbitrary baud rates, no Bxxxx mess needed)? Example:
+ *
+ * #include <asm/termios.h>
+ * #include <asm/ioctls.h>
+ * struct termios2 t;
+ * ioctl(fd, TCGETS2, &t);
+ * t.c_ospeed = t.c_ispeed = 543210;
+ * t.c_cflag &= ~CBAUD;
+ * t.c_cflag |= BOTHER;
+ * ioctl(fd, TCSETS2, &t);
+ */
+
enum { NUM_SPEEDS = ARRAY_SIZE(speeds) };
unsigned FAST_FUNC tty_baud_to_value(speed_t speed)
@@ -114,7 +129,7 @@ unsigned FAST_FUNC tty_baud_to_value(speed_t speed)
do {
if (speed == speeds[i].speed) {
if (speeds[i].value & 0x8000u) {
- return ((unsigned long) (speeds[i].value) & 0x7fffU) * 200;
+ return ((unsigned)(speeds[i].value) & 0x7fffU) * 200;
}
return speeds[i].value;
}