x86, setup: Only set early_serial_base after port is initialized

[net-next-2.6.git] / arch / x86 / boot / tty.c

diff --git a/arch/x86/boot/tty.c b/arch/x86/boot/tty.c
index 01ec69c901c7a595e88748f24880a5104af553fe..ff4b27a0fc5e8bd81eb6ea9b6325cb96f000039b 100644 (file)
--- a/arch/x86/boot/tty.c
+++ b/arch/x86/boot/tty.c
@@ -10,23 +10,51 @@
  * ----------------------------------------------------------------------- */
 
 /*
- * Very simple screen I/O
- * XXX: Probably should add very simple serial I/O?
+ * Very simple screen and serial I/O
  */
 
 #include "boot.h"
 
+#define DEFAULT_SERIAL_PORT 0x3f8 /* ttyS0 */
+
+static int     early_serial_base;
+
+#define XMTRDY          0x20
+
+#define DLAB           0x80
+
+#define TXR             0       /*  Transmit register (WRITE) */
+#define RXR             0       /*  Receive register  (READ)  */
+#define IER             1       /*  Interrupt Enable          */
+#define IIR             2       /*  Interrupt ID              */
+#define FCR             2       /*  FIFO control              */
+#define LCR             3       /*  Line control              */
+#define MCR             4       /*  Modem control             */
+#define LSR             5       /*  Line Status               */
+#define MSR             6       /*  Modem Status              */
+#define DLL             0       /*  Divisor Latch Low         */
+#define DLH             1       /*  Divisor latch High        */
+
+#define DEFAULT_BAUD 9600
+
 /*
  * These functions are in .inittext so they can be used to signal
  * error during initialization.
  */
 
-void __attribute__((section(".inittext"))) putchar(int ch)
+static void __attribute__((section(".inittext"))) serial_putchar(int ch)
 {
-       struct biosregs ireg;
+       unsigned timeout = 0xffff;
 
-       if (ch == '\n')
-               putchar('\r');  /* \n -> \r\n */
+       while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
+               cpu_relax();
+
+       outb(ch, early_serial_base + TXR);
+}
+
+static void __attribute__((section(".inittext"))) bios_putchar(int ch)
+{
+       struct biosregs ireg;
 
        initregs(&ireg);
        ireg.bx = 0x0007;
@@ -36,6 +64,17 @@ void __attribute__((section(".inittext"))) putchar(int ch)
        intcall(0x10, &ireg, NULL);
 }
 
+void __attribute__((section(".inittext"))) putchar(int ch)
+{
+       if (ch == '\n')
+               putchar('\r');  /* \n -> \r\n */
+
+       bios_putchar(ch);
+
+       if (early_serial_base != 0)
+               serial_putchar(ch);
+}
+
 void __attribute__((section(".inittext"))) puts(const char *str)
 {
        while (*str)
@@ -112,3 +151,123 @@ int getchar_timeout(void)
 
        return 0;               /* Timeout! */
 }
+
+static void early_serial_init(int port, int baud)
+{
+       unsigned char c;
+       unsigned divisor;
+
+       outb(0x3, port + LCR);  /* 8n1 */
+       outb(0, port + IER);    /* no interrupt */
+       outb(0, port + FCR);    /* no fifo */
+       outb(0x3, port + MCR);  /* DTR + RTS */
+
+       divisor = 115200 / baud;
+       c = inb(port + LCR);
+       outb(c | DLAB, port + LCR);
+       outb(divisor & 0xff, port + DLL);
+       outb((divisor >> 8) & 0xff, port + DLH);
+       outb(c & ~DLAB, port + LCR);
+
+       early_serial_base = port;
+
+       printf("Early serial console at I/O port 0x%x baud: %d\n", port, baud);
+}
+
+static void parse_earlyprintk(void)
+{
+       int baud = DEFAULT_BAUD;
+       char arg[32];
+       int pos = 0;
+       int port = 0;
+
+       if (cmdline_find_option("earlyprintk", arg, sizeof arg) > 0) {
+               char *e;
+
+               if (!strncmp(arg, "serial", 6)) {
+                       port = DEFAULT_SERIAL_PORT;
+                       pos += 6;
+               }
+
+               if (arg[pos] == ',')
+                       pos++;
+
+               if (!strncmp(arg, "ttyS", 4)) {
+                       static const int bases[] = { 0x3f8, 0x2f8 };
+                       int idx = 0;
+
+                       if (!strncmp(arg + pos, "ttyS", 4))
+                               pos += 4;
+
+                       if (arg[pos++] == '1')
+                               idx = 1;
+
+                       port = bases[idx];
+               }
+
+               if (arg[pos] == ',')
+                       pos++;
+
+               baud = simple_strtoull(arg + pos, &e, 0);
+               if (baud == 0 || arg + pos == e)
+                       baud = DEFAULT_BAUD;
+       }
+
+       if (port)
+               early_serial_init(port, baud);
+}
+
+#define BASE_BAUD (1843200/16)
+static unsigned int probe_baud(int port)
+{
+       unsigned char lcr, dll, dlh;
+       unsigned int quot;
+
+       lcr = inb(port + LCR);
+       outb(lcr | DLAB, port + LCR);
+       dll = inb(port + DLL);
+       dlh = inb(port + DLH);
+       outb(lcr, port + LCR);
+       quot = (dlh << 8) | dll;
+
+       return BASE_BAUD / quot;
+}
+
+static void parse_console_uart8250(void)
+{
+       char optstr[64], *options;
+       int baud = DEFAULT_BAUD;
+       int port = 0;
+
+       /*
+        * console=uart8250,io,0x3f8,115200n8
+        * need to make sure it is last one console !
+        */
+       if (cmdline_find_option("console", optstr, sizeof optstr) <= 0)
+               return;
+
+       options = optstr;
+
+       if (!strncmp(options, "uart8250,io,", 12))
+               port = simple_strtoull(options + 12, &options, 0);
+       else if (!strncmp(options, "uart,io,", 8))
+               port = simple_strtoull(options + 8, &options, 0);
+       else
+               return;
+
+       if (options && (options[0] == ','))
+               baud = simple_strtoull(options + 1, &options, 0);
+       else
+               baud = probe_baud(port);
+
+       if (port)
+               early_serial_init(port, baud);
+}
+
+void console_init(void)
+{
+       parse_earlyprintk();
+
+       if (!early_serial_base)
+               parse_console_uart8250();
+}