From: Thomas Veerman <thomas@minix3.org>
Date: Wed, 17 Oct 2012 14:57:08 +0000 (+0000)
Subject: Kernel: busy wait until serial out has finished
X-Git-Tag: v3.2.1~253
X-Git-Url: http://zhaoyanbai.com/repos/%22http:/www.isc.org/icons/%7B%24global.css%7D?a=commitdiff_plain;h=87de14114114a7446b179d5441ddeec8d76d2b76;p=minix.git

Kernel: busy wait until serial out has finished
---

diff --git a/kernel/arch/arm/omap_serial.c b/kernel/arch/arm/omap_serial.c
index 30e744e99..5a598c796 100644
--- a/kernel/arch/arm/omap_serial.c
+++ b/kernel/arch/arm/omap_serial.c
@@ -9,9 +9,14 @@ void omap3_ser_putc(char c)
 
     /* Wait until FIFO's empty */
     for (i = 0; i < 100000; i++)
-	if (mmio_read(OMAP3_UART3_LSR) & OMAP3_LSR_TX_FIFO_E)
+	if (mmio_read(OMAP3_UART3_LSR) & OMAP3_LSR_THRE)
 	    break;
 
     /* Write character */
     mmio_write(OMAP3_UART3_THR, c);
+
+    /* And wait again until FIFO's empty to prevent TTY from overwriting */
+    for (i = 0; i < 100000; i++)
+	if (mmio_read(OMAP3_UART3_LSR) & (OMAP3_LSR_THRE | OMAP3_LSR_TEMT))
+	    break;
 }
diff --git a/kernel/arch/arm/omap_serial.h b/kernel/arch/arm/omap_serial.h
index 278d02883..f3b0626ef 100644
--- a/kernel/arch/arm/omap_serial.h
+++ b/kernel/arch/arm/omap_serial.h
@@ -12,7 +12,8 @@
 #define OMAP3_SSR 0x044 /* Supplementary status register */
 
 /* Line status register fields */
-#define OMAP3_LSR_TX_FIFO_E    (1 << 5) /* Transmit FIFO empty */
+#define OMAP3_LSR_TEMT    0x40 /* Transmitter empty */
+#define OMAP3_LSR_THRE    0x20 /* Transmit-hold-register empty */
 
 /* Supplementary status register fields */
 #define OMAP3_SSR_TX_FIFO_FULL (1 << 0) /* Transmit FIFO full */