[PATCH] ip22 console selection fixes

[William Jhun <wjhun@Oswego.EDU>]

This patch fixes some problems in selecting which console to use on the
ip22s.

- Replace unobvious ttyS with arc for the arc console device name
- If ARC var console=d*, use serial. If 'g', use Newport only. If
  neither or not set, default to ARC. Old code was disabling ARC
  console and using serial console if CONFIG_ARC_CONSOLE was set. (why?!)
- ArcGetEnvironmentVariable() can conceivably return NULL, so don't
  blindly dereference.

Thanks,
Will

Index: arch/mips/arc/arc_con.c
===================================================================
RCS file: /cvs/linux/arch/mips/arc/arc_con.c,v
retrieving revision 1.1.4.3
diff -u -r1.1.4.3 arc_con.c
--- arch/mips/arc/arc_con.c     2002/08/05 23:53:30     1.1.4.3
+++ arch/mips/arc/arc_con.c     2002/09/17 08:57:12
@@ -39,7 +39,7 @@
 }

 static struct console arc_cons = {
-       name:           "ttyS",
+       name:           "arc",
        write:          prom_console_write,
        device:         prom_console_device,
        setup:          prom_console_setup,
Index: arch/mips/sgi-ip22/ip22-setup.c
===================================================================
RCS file: /cvs/linux/arch/mips/sgi-ip22/ip22-setup.c,v
retrieving revision 1.1.2.13
diff -u -r1.1.2.13 ip22-setup.c
--- arch/mips/sgi-ip22/ip22-setup.c     2002/07/23 16:39:10     1.1.2.13
+++ arch/mips/sgi-ip22/ip22-setup.c     2002/09/17 08:57:12
@@ -162,19 +162,22 @@
         * line and "d2" for the second serial line.
         */
        ctype = ArcGetEnvironmentVariable("console");
-       if (*ctype == 'd') {
+       if (ctype && *ctype == 'd') {
 #ifdef CONFIG_SERIAL_CONSOLE
                if(*(ctype + 1) == '2')
                        console_setup("ttyS1");
                else
                        console_setup("ttyS0");
 #endif
-       } else {
+       }
 #ifdef CONFIG_ARC_CONSOLE
-               prom_flags &= PROM_FLAG_USE_AS_CONSOLE;
-               console_setup("ttyS0");
-#endif
+       else if (!ctype || *ctype != 'g') {
+               /* Use ARC if we don't want serial ('d') or
+                * Newport ('g'). */
+               prom_flags |= PROM_FLAG_USE_AS_CONSOLE;
+               console_setup("arc");
        }
+#endif

 #ifdef CONFIG_REMOTE_DEBUG
        kgdb_ttyd = prom_getcmdline();
@@ -201,7 +204,7 @@

 #ifdef CONFIG_VT
 #ifdef CONFIG_SGI_NEWPORT_CONSOLE
-       {
+       if (ctype && *ctype == 'g'){
                unsigned long *gfxinfo;
                long (*__vec)(void) = (void *) *(long *)((PROMBLOCK)->pvector + 
0x20);

@@ -209,29 +212,29 @@
                sgi_gfxaddr = ((gfxinfo[1] >= 0xa0000000
                               && gfxinfo[1] <= 0xc0000000)
                               ? gfxinfo[1] - 0xa0000000 : 0);
+
+               /* newport addresses? */
+               if (sgi_gfxaddr == 0x1f0f0000 || sgi_gfxaddr == 0x1f4f0000) {
+                       conswitchp = &newport_con;
+
+                       screen_info = (struct screen_info) {
+                               0, 0,           /* orig-x, orig-y */
+                               0,              /* unused */
+                               0,              /* orig_video_page */
+                               0,              /* orig_video_mode */
+                               160,            /* orig_video_cols */
+                               0, 0, 0,        /* unused, ega_bx, unused */
+                               64,             /* orig_video_lines */
+                               0,              /* orig_video_isVGA */
+                               16              /* orig_video_points */
+                       };
+               }
        }
-       /* newport addresses? */
-       if (sgi_gfxaddr == 0x1f0f0000 || sgi_gfxaddr == 0x1f4f0000) {
-               conswitchp = &newport_con;
-
-               screen_info = (struct screen_info) {
-                       0, 0,           /* orig-x, orig-y */
-                       0,              /* unused */
-                       0,              /* orig_video_page */
-                       0,              /* orig_video_mode */
-                       160,            /* orig_video_cols */
-                       0, 0, 0,        /* unused, ega_bx, unused */
-                       64,             /* orig_video_lines */
-                       0,              /* orig_video_isVGA */
-                       16              /* orig_video_points */
-               };
-       } else {
-               conswitchp = &dummy_con;
-       }
-#else
-#ifdef CONFIG_DUMMY_CONSOLE
-       conswitchp = &dummy_con;
 #endif
+#ifdef CONFIG_DUMMY_CONSOLE
+       /* Either if newport console wasn't used or failed to initialize. */
+       if(conswitchp != &newport_con)
+               conswitchp = &dummy_con;
 #endif
 #endif

---

|William Y. Jhun - wjhun@oswego.edu