Add support for sending debug messages to a serial port.

[seabios.git] / src / serial.c

diff --git a/src/serial.c b/src/serial.c
index 8ca7e36781e7737b238b5103029c3a78dfb74656..026c399dc930843b7633cb2755bccb3aa35bc3a7 100644 (file)
--- a/src/serial.c
+++ b/src/serial.c
@@ -54,6 +54,7 @@ getComAddr(struct bregs *regs)
     return addr;
 }
 
+// SERIAL - INITIALIZE PORT
 static void
 handle_1400(struct bregs *regs)
 {
@@ -75,14 +76,10 @@ handle_1400(struct bregs *regs)
     set_success(regs);
 }
 
-static void
-handle_1401(struct bregs *regs)
+static int
+write_serial(u16 addr, u16 timeout, char c)
 {
-    u16 addr = getComAddr(regs);
-    if (!addr)
-        return;
     u16 timer = GET_BDA(timer_counter);
-    u16 timeout = GET_BDA(com_timeout[regs->dx]);
     while (((inb(addr+5) & 0x60) != 0x60) && (timeout)) {
         u16 val16 = GET_BDA(timer_counter);
         if (val16 != timer) {
@@ -90,14 +87,29 @@ handle_1401(struct bregs *regs)
             timeout--;
         }
     }
-    if (timeout)
-        outb(regs->al, addr);
-    regs->ah = inb(addr+5);
     if (!timeout)
+        // Ran out of time.
+        return -1;
+    outb(c, addr);
+    return 0;
+}
+
+// SERIAL - WRITE CHARACTER TO PORT
+static void
+handle_1401(struct bregs *regs)
+{
+    u16 addr = getComAddr(regs);
+    if (!addr)
+        return;
+    u16 timeout = GET_BDA(com_timeout[regs->dx]);
+    int ret = write_serial(addr, timeout, regs->al);
+    regs->ah = inb(addr+5);
+    if (ret)
         regs->ah |= 0x80;
     set_success(regs);
 }
 
+// SERIAL - READ CHARACTER FROM PORT
 static void
 handle_1402(struct bregs *regs)
 {
@@ -122,6 +134,7 @@ handle_1402(struct bregs *regs)
     set_success(regs);
 }
 
+// SERIAL - GET PORT STATUS
 static void
 handle_1403(struct bregs *regs)
 {
@@ -158,6 +171,26 @@ handle_14(struct bregs *regs)
 }
 
 
+/****************************************************************
+ * Serial debugging
+ ****************************************************************/
+
+#define BX_DEBUG_PORT 0x03f8
+
+void
+debug_serial_setup()
+{
+    /* setup for serial logging: 8N1 */
+    outb(0x03, BX_DEBUG_PORT+3);
+}
+
+void
+debug_serial(char c)
+{
+    write_serial(BX_DEBUG_PORT, 0x0a, c);
+}
+
+
 /****************************************************************
  * LPT ports
  ****************************************************************/