Making OpenBIOS support Apple partition-zero booting

To speed up my development cycle on iQUIK and make it less painful I really needed to get OpenBIOS to boot via bootcode correctly. The current sources (r1272) hard code the load address for the legacy QUIK bootloader, which makes it useless for me or for anyone else (like the NetBSD or OpenBSD bootloaders).

I didn't try very hard, but the end result works, and hopefully the OpenBIOS guys will just take my fix.

SVN workflow seems so...senescent compared to git. Sigh.

Index: forth/debugging/client.fs
===================================================================
--- forth/debugging/client.fs (revision 1272)
+++ forth/debugging/client.fs (working copy)
@@ -28,7 +28,13 @@
 0 state-valid !
 
 variable want-bootcode
+variable bootcode-base
+variable bootcode-size
+variable bootcode-entry
 0 want-bootcode !
+0 bootcode-base !
+0 bootcode-size !
+0 bootcode-entry !
 
 variable file-size
 
Index: libopenbios/bootcode_load.c
===================================================================
--- libopenbios/bootcode_load.c (revision 1272)
+++ libopenbios/bootcode_load.c (working copy)
@@ -12,13 +12,11 @@
 #define printf printk
 #define debug printk
 
-#define OLDWORLD_BOOTCODE_BASEADDR (0x3f4000)
-
 int 
 bootcode_load(ihandle_t dev)
 {
     int retval = -1, count = 0, fd;
-    unsigned long bootcode, loadbase, offset;
+    unsigned long bootcode, loadbase, offset, loadsize, entry;
 
     /* Mark the saved-program-state as invalid */
     feval("0 state-valid !");
@@ -33,34 +31,59 @@
     loadbase = POP();
     
 #ifdef CONFIG_PPC
-    /* ...except that QUIK (the only known user of %BOOT to date) is built
-       with a hard-coded address of 0x3f4000. Let's just use this for the
-       moment on both New World and Old World Macs, allowing QUIK to also
-       work under a New World Mac. If we find another user of %BOOT we can
-       rethink this later. PReP machines should be left unaffected. */
+    /*
+     * Apple OF does not honor load-base and instead uses pmBootLoad
+     * value from the boot partition descriptor.
+     *
+     * Tested with:
+     *   a debian image with QUIK installed
+     *   a debian image with iQUIK installed (https://github.com/andreiw/quik)
+     *   an IQUIK boot floppy
+     *   a NetBSD boot floppy (boots stage 2)
+     */
     if (is_apple()) {
-        loadbase = OLDWORLD_BOOTCODE_BASEADDR;
+      feval("bootcode-base @");
+      loadbase = POP();
+      feval("bootcode-size @");
+      loadsize = POP();
+      feval("bootcode-entry @");
+      entry = POP();
+
+      printk("bootcode base 0x%lx, size 0x%lx, entry 0x%lx\n",
+             loadbase, loadsize, entry);
+    } else {
+      entry = loadbase;
+
+      /* Load as much as we can. */
+      loadsize = 0;
     }
 #endif
     
     bootcode = loadbase;
     offset = 0;
     
-    while(1) {
+    if (loadsize) {
+      if (seek_io(fd, offset) != -1)
+        count = read_io(fd, (void *) bootcode, loadsize);
+    } else {
+      while(1) {
         if (seek_io(fd, offset) == -1)
-            break;
+          break;
         count = read_io(fd, (void *)bootcode, 512);
         offset += count;
         bootcode += count;
+      }
     }
 
     /* If we didn't read anything then exit */
     if (!count) {
         goto out;
     }
+
+    printk("entry = 0x%lx\n", entry);
     
     /* Initialise saved-program-state */
-    PUSH(loadbase);
+    PUSH(entry);
     feval("saved-program-state >sps.entry !");
     PUSH(offset);
     feval("saved-program-state >sps.file-size !");
Index: libopenbios/load.c
===================================================================
--- libopenbios/load.c (revision 1272)
+++ libopenbios/load.c (working copy)
@@ -1,6 +1,6 @@
 /*
  *   Creation Date: <2010/06/25 20:00:00 mcayland>
- *   Time-stamp: <2010/06/25 20:00:00 mcayland>
+ *   Time-stamp: <2014-03-05 03:18:49 andreiw>
  *
  * <load.c>
  *
Index: packages/mac-parts.c
===================================================================
--- packages/mac-parts.c (revision 1272)
+++ packages/mac-parts.c (working copy)
@@ -1,6 +1,6 @@
 /*
  *   Creation Date: <2003/12/04 17:07:05 samuel>
- *   Time-stamp: <2004/01/07 19:36:09 samuel>
+ *   Time-stamp: <2014-03-05 03:42:07 andreiw>
  *
  * <mac-parts.c>
  *
@@ -237,6 +237,19 @@
      size = (long long)__be32_to_cpu(par.pmPartBlkCnt) * bs; 
      
      if (want_bootcode) {
+  ucell loadaddr = 0;
+  ucell loadsize = 0;
+  ucell loadentry = 0;
+
+  loadaddr = __be32_to_cpu(par.pmBootLoad);
+  loadsize = __be32_to_cpu(par.pmBootSize);
+  loadentry = __be32_to_cpu(par.pmBootEntry);
+  PUSH(loadaddr);
+  feval("bootcode-base !");
+  PUSH(loadsize);
+  feval("bootcode-size !");
+  PUSH(loadentry);
+  feval("bootcode-entry !");
   offs += (long long)__be32_to_cpu(par.pmLgBootStart) * bs;
   size = (long long)__be32_to_cpu(par.pmBootSize);
      }
@@ -249,6 +262,10 @@
      di->size_hi = size >> BITS;
      di->size_lo = size & (ucell) -1;
 
+     if (want_bootcode) {
+       goto out;
+     }
+
      /* We have a valid partition - so probe for a filesystem at the current offset */
      DPRINTF("mac-parts: about to probe for fs\n");
      DPUSH( offs );
@@ -277,7 +294,7 @@
   
       /* If we have been asked to open a particular file, interpose the filesystem package with 
       the passed filename as an argument */
-      if (!want_bootcode && strlen(argstr)) {
+      if ( strlen(argstr)) {
        push_str( argstr );
        PUSH_ph( ph );
        fword("interpose");
@@ -286,6 +303,10 @@
       goto out;
      } else {
       DPRINTF("mac-parts: no filesystem found on partition %d; bypassing misc-files interpose\n", parnum);
+
+      /* Fail out instead of having macparts_load get called uselessly, allowing trying the next
+         boot device */
+      ret = 0;
      }
  }

This does make booting iQUIK on OpenBIOS now very easy.

qemu-system-ppc -hda ~/src/quik/distrib/floppy-cfg.img -prom-env "boot-file=hd:3"