1 files changed, 116 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/com32/lib/vdprintf.c b/contrib/syslinux-4.02/com32/lib/vdprintf.c
new file mode 100644
index 0000000..d74f278
--- /dev/null
+++ b/contrib/syslinux-4.02/com32/lib/vdprintf.c
@@ -0,0 +1,116 @@
+/*
+ * vdprintf.c
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdarg.h>
+#include <unistd.h>
+#include <inttypes.h>
+#include <sys/io.h>
+#include <sys/cpu.h>
+
+#undef DEBUG
+#define DEBUG 1
+#include <dprintf.h>
+
+#define BUFFER_SIZE	4096
+
+enum serial_port_regs {
+    THR = 0,
+    RBR = 0,
+    DLL = 0,
+    DLM = 1,
+    IER = 1,
+    IIR = 2,
+    FCR = 2,
+    LCR = 3,
+    MCR = 4,
+    LSR = 5,
+    MSR = 6,
+    SCR = 7,
+};
+
+#ifndef DEBUG_PORT
+# define DEBUG_PORT 0x03f8	/* I/O base address */
+#endif
+
+static const uint16_t debug_base = DEBUG_PORT;
+
+static void debug_putc(char c)
+{
+    if (c == '\n')
+	debug_putc('\r');
+
+    while ((inb(debug_base + LSR) & 0x20) == 0)
+	cpu_relax();
+    outb(c, debug_base + THR);
+}
+
+void vdprintf(const char *format, va_list ap)
+{
+    int rv;
+    char buffer[BUFFER_SIZE];
+    char *p;
+    static bool debug_init = false;
+    static bool debug_ok   = false;
+
+    rv = vsnprintf(buffer, BUFFER_SIZE, format, ap);
+
+    if (rv < 0)
+	return;
+
+    if (rv > BUFFER_SIZE - 1)
+	rv = BUFFER_SIZE - 1;
+
+    /*
+     * This unconditionally outputs to a serial port at 0x3f8 regardless of
+     * if one is enabled or not (this means we don't have to enable the real
+     * serial console and therefore get conflicting output.)
+     */
+    if (__unlikely(!debug_init)) {
+	uint8_t dll, dlm, lcr;
+
+	debug_init = true;
+
+	cli();
+
+	/* Initialize the serial port to 115200 n81 with FIFOs enabled */
+	outb(0x83, debug_base + LCR);
+	outb(0x01, debug_base + DLL);
+	outb(0x00, debug_base + DLM);
+	(void)inb(debug_base + IER);	/* Synchronize */
+	dll = inb(debug_base + DLL);
+	dlm = inb(debug_base + DLM);
+	lcr = inb(debug_base + LCR);
+	
+	outb(0x03, debug_base + LCR);
+	(void)inb(debug_base + IER);	/* Synchronize */
+
+	outb(0x00, debug_base + IER);
+	(void)inb(debug_base + IER);	/* Synchronize */
+
+	sti();
+
+	if (dll != 0x01 || dlm != 0x00 || lcr != 0x83) {
+	    /* No serial port present */
+	    return;
+	}
+
+	outb(0x01, debug_base + FCR);
+	(void)inb(debug_base + IER);	/* Synchronize */
+	if (inb(debug_base + IIR) < 0xc0) {
+	    outb(0x00, debug_base + FCR); /* Disable non-functional FIFOs */
+	    (void)inb(debug_base + IER);	/* Synchronize */
+	}
+
+	debug_ok = true;
+    }
+
+    if (!debug_ok)
+	return;
+
+    p = buffer;
+    while (rv--)
+	debug_putc(*p++);
+}