Author: ian
Date: Tue Sep 30 23:01:11 2014
New Revision: 272334
URL: http://svnweb.freebsd.org/changeset/base/272334
Log:
Return the actual baud rate programmed in the hardware rather than 115200.
This allows the "3wire" entry in /etc/ttys (with no speed specified) to work.
Modified:
head/sys/dev/uart/uart_dev_imx.c
Modified: head/sys/dev/uart/uart_dev_imx.c
==============================================================================
--- head/sys/dev/uart/uart_dev_imx.c Tue Sep 30 21:28:05 2014
(r272333)
+++ head/sys/dev/uart/uart_dev_imx.c Tue Sep 30 23:01:11 2014
(r272334)
@@ -90,6 +90,45 @@ imx_uart_probe(struct uart_bas *bas)
return (0);
}
+static u_int
+imx_uart_getbaud(struct uart_bas *bas)
+{
+ uint32_t rate, ubir, ubmr;
+ u_int baud, blo, bhi, i;
+ static const u_int predivs[] = {6, 5, 4, 3, 2, 1, 7, 1};
+ static const u_int std_rates[] = {
+ 9600, 14400, 19200, 38400, 57600, 115200, 230400, 460800, 921600
+ };
+
+ /*
+ * Get the baud rate the hardware is programmed for, then search the
+ * table of standard baud rates for a number that's within 3% of the
+ * actual rate the hardware is programmed for. It's more comforting to
+ * see that your console is running at 115200 than 114942. Note that
+ * here we cannot make a simplifying assumption that the predivider and
+ * numerator are 1 (like we do when setting the baud rate), because we
+ * don't know what u-boot might have set up.
+ */
+ i = (GETREG(bas, REG(UFCR)) & IMXUART_UFCR_RFDIV_MASK) >>
+ IMXUART_UFCR_RFDIV_SHIFT;
+ rate = imx_ccm_uart_hz() / predivs[i];
+ ubir = GETREG(bas, REG(UBIR)) + 1;
+ ubmr = GETREG(bas, REG(UBMR)) + 1;
+ baud = ((rate / 16 ) * ubir) / ubmr;
+
+ blo = (baud * 100) / 103;
+ bhi = (baud * 100) / 97;
+ for (i = 0; i < nitems(std_rates); i++) {
+ rate = std_rates[i];
+ if (rate >= blo && rate <= bhi) {
+ baud = rate;
+ break;
+ }
+ }
+
+ return (baud);
+}
+
static void
imx_uart_init(struct uart_bas *bas, int baudrate, int databits,
int stopbits, int parity)
@@ -348,8 +387,7 @@ imx_uart_bus_ioctl(struct uart_softc *sc
/* TODO */
break;
case UART_IOCTL_BAUD:
- /* TODO */
- *(int*)data = 115200;
+ *(u_int*)data = imx_uart_getbaud(bas);
break;
default:
error = EINVAL;
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