Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1042 insertions, 0 deletions

diff --git a/drivers/nubus/nubus.c b/drivers/nubus/nubus.c
new file mode 100644
index 00000000000..14cbe34eb89
--- /dev/null
+++ b/drivers/nubus/nubus.c
@@ -0,0 +1,1042 @@
+/*
+ *      Macintosh Nubus Interface Code
+ *
+ *      Originally by Alan Cox
+ *
+ *      Mostly rewritten by David Huggins-Daines, C. Scott Ananian,
+ *      and others.
+ */
+
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/nubus.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <asm/setup.h>
+#include <asm/system.h>
+#include <asm/page.h>
+#include <asm/hwtest.h>
+#include <linux/proc_fs.h>
+#include <asm/mac_via.h>
+#include <asm/mac_oss.h>
+
+extern void via_nubus_init(void);
+extern void oss_nubus_init(void);
+
+/* Constants */
+
+/* This is, of course, the size in bytelanes, rather than the size in
+   actual bytes */
+#define FORMAT_BLOCK_SIZE 20
+#define ROM_DIR_OFFSET 0x24
+
+#define NUBUS_TEST_PATTERN 0x5A932BC7
+
+/* Define this if you like to live dangerously - it is known not to
+   work on pretty much every machine except the Quadra 630 and the LC
+   III. */
+#undef I_WANT_TO_PROBE_SLOT_ZERO
+
+/* This sometimes helps combat failure to boot */
+#undef TRY_TO_DODGE_WSOD
+
+/* Globals */
+
+struct nubus_dev*   nubus_devices;
+struct nubus_board* nubus_boards;
+
+/* Meaning of "bytelanes":
+
+   The card ROM may appear on any or all bytes of each long word in
+   NuBus memory.  The low 4 bits of the "map" value found in the
+   format block (at the top of the slot address space, as well as at
+   the top of the MacOS ROM) tells us which bytelanes, i.e. which byte
+   offsets within each longword, are valid.  Thus:
+
+   A map of 0x0f, as found in the MacOS ROM, means that all bytelanes
+   are valid.
+
+   A map of 0xf0 means that no bytelanes are valid (We pray that we
+   will never encounter this, but stranger things have happened)
+
+   A map of 0xe1 means that only the MSB of each long word is actually
+   part of the card ROM.  (We hope to never encounter NuBus on a
+   little-endian machine.  Again, stranger things have happened)
+
+   A map of 0x78 means that only the LSB of each long word is valid.
+
+   Etcetera, etcetera.  Hopefully this clears up some confusion over
+   what the following code actually does.  */
+ 
+static inline int not_useful(void *p, int map)
+{
+        unsigned long pv=(unsigned long)p;
+        pv &= 3;
+        if(map & (1<<pv))
+                return 0;
+        return 1;
+}
+ 
+static unsigned long nubus_get_rom(unsigned char **ptr, int len, int map)
+{
+        /* This will hold the result */
+        unsigned long v = 0;
+        unsigned char *p = *ptr;
+
+        while(len)
+        {
+                v <<= 8;
+                while(not_useful(p,map))
+                        p++;
+                v |= *p++;
+                len--;
+        }
+        *ptr = p;
+        return v;
+}
+
+static void nubus_rewind(unsigned char **ptr, int len, int map)
+{
+        unsigned char *p=*ptr;
+
+        /* Sanity check */
+        if(len > 65536)
+                printk(KERN_ERR "rewind of 0x%08x!\n", len);
+        while(len)
+        {
+                do
+                {
+                        p--;
+                }
+                while(not_useful(p, map));
+                len--;
+        }
+        *ptr=p;
+}
+
+static void nubus_advance(unsigned char **ptr, int len, int map)
+{
+        unsigned char *p = *ptr;
+        if(len>65536)
+                printk(KERN_ERR "advance of 0x%08x!\n", len);
+        while(len)
+        {
+                while(not_useful(p,map))
+                        p++;
+                        p++;
+                len--;
+        }
+        *ptr = p;
+}
+
+static void nubus_move(unsigned char **ptr, int len, int map)
+{
+        if(len > 0)
+                nubus_advance(ptr, len, map);
+        else if(len < 0)
+                nubus_rewind(ptr, -len, map);
+}
+
+/* Now, functions to read the sResource tree */
+
+/* Each sResource entry consists of a 1-byte ID and a 3-byte data
+   field.  If that data field contains an offset, then obviously we
+   have to expand it from a 24-bit signed number to a 32-bit signed
+   number. */
+
+static inline long nubus_expand32(long foo)
+{
+        if(foo & 0x00800000)    /* 24bit negative */
+                foo |= 0xFF000000;
+        return foo;
+}
+
+static inline void *nubus_rom_addr(int slot)
+{       
+        /*
+         *      Returns the first byte after the card. We then walk
+         *      backwards to get the lane register and the config
+         */
+        return (void *)(0xF1000000+(slot<<24));
+}
+
+static unsigned char *nubus_dirptr(const struct nubus_dirent *nd)
+{
+        unsigned char *p = nd->base;
+        /* Essentially, just step over the bytelanes using whatever
+           offset we might have found */
+        nubus_move(&p, nubus_expand32(nd->data), nd->mask);
+        /* And return the value */
+        return p;
+}
+
+/* These two are for pulling resource data blocks (i.e. stuff that's
+   pointed to with offsets) out of the card ROM. */
+
+void nubus_get_rsrc_mem(void *dest, const struct nubus_dirent* dirent,
+                        int len)
+{
+        unsigned char *t = (unsigned char *)dest;
+        unsigned char *p = nubus_dirptr(dirent);
+        while(len)
+        {
+                *t++ = nubus_get_rom(&p, 1, dirent->mask);
+                len--;
+        }
+}
+
+void nubus_get_rsrc_str(void *dest, const struct nubus_dirent* dirent,
+                        int len)
+{
+        unsigned char *t=(unsigned char *)dest;
+        unsigned char *p = nubus_dirptr(dirent);
+        while(len)
+        {
+                *t = nubus_get_rom(&p, 1, dirent->mask);
+                if(!*t++)
+                        break;
+                len--;
+        }
+}
+
+int nubus_get_root_dir(const struct nubus_board* board,
+                       struct nubus_dir* dir)
+{
+        dir->ptr = dir->base = board->directory;
+        dir->done = 0;
+        dir->mask = board->lanes;
+        return 0;
+}
+
+/* This is a slyly renamed version of the above */
+int nubus_get_func_dir(const struct nubus_dev* dev,
+                       struct nubus_dir* dir)
+{
+        dir->ptr = dir->base = dev->directory;
+        dir->done = 0;
+        dir->mask = dev->board->lanes;
+        return 0;
+}
+
+int nubus_get_board_dir(const struct nubus_board* board,
+                        struct nubus_dir* dir)
+{
+        struct nubus_dirent ent;
+        
+        dir->ptr = dir->base = board->directory;
+        dir->done = 0;
+        dir->mask = board->lanes;
+
+        /* Now dereference it (the first directory is always the board
+           directory) */
+        if (nubus_readdir(dir, &ent) == -1)
+                return -1;
+        if (nubus_get_subdir(&ent, dir) == -1)
+                return -1;
+        return 0;
+}
+
+int nubus_get_subdir(const struct nubus_dirent *ent,
+                     struct nubus_dir *dir)
+{
+        dir->ptr = dir->base = nubus_dirptr(ent);
+        dir->done = 0;
+        dir->mask = ent->mask;
+        return 0;
+}
+
+int nubus_readdir(struct nubus_dir *nd, struct nubus_dirent *ent)
+{
+        u32 resid;
+        if (nd->done)
+                return -1;
+
+        /* Do this first, otherwise nubus_rewind & co are off by 4 */
+        ent->base = nd->ptr;
+
+        /* This moves nd->ptr forward */
+        resid = nubus_get_rom(&nd->ptr, 4, nd->mask);
+
+        /* EOL marker, as per the Apple docs */
+        if((resid&0xff000000) == 0xff000000)
+        {
+                /* Mark it as done */
+                nd->done = 1;
+                return -1;
+        }
+
+        /* First byte is the resource ID */
+        ent->type  = resid >> 24;
+        /* Low 3 bytes might contain data (or might not) */
+        ent->data = resid & 0xffffff;
+        ent->mask  = nd->mask;
+        return 0;
+}
+
+int nubus_rewinddir(struct nubus_dir* dir)
+{
+        dir->ptr = dir->base;
+        return 0;
+}
+
+/* Driver interface functions, more or less like in pci.c */
+
+struct nubus_dev*
+nubus_find_device(unsigned short category,
+                  unsigned short type,
+                  unsigned short dr_hw,
+                  unsigned short dr_sw,
+                  const struct nubus_dev* from)
+{
+        struct nubus_dev* itor =
+                from ? from->next : nubus_devices;
+
+        while (itor) {
+                if (itor->category == category
+                    && itor->type == type
+                    && itor->dr_hw == dr_hw
+                    && itor->dr_sw == dr_sw)
+                        return itor;
+                itor = itor->next;
+        }
+        return NULL;
+}
+
+struct nubus_dev*
+nubus_find_type(unsigned short category,
+                unsigned short type,
+                const struct nubus_dev* from)
+{
+        struct nubus_dev* itor =
+                from ? from->next : nubus_devices;
+
+        while (itor) {
+                if (itor->category == category
+                    && itor->type == type)
+                        return itor;
+                itor = itor->next;
+        }
+        return NULL;
+}
+
+struct nubus_dev*
+nubus_find_slot(unsigned int slot,
+                const struct nubus_dev* from)
+{
+        struct nubus_dev* itor =
+                from ? from->next : nubus_devices;
+        
+        while (itor) {
+                if (itor->board->slot == slot)
+                        return itor;
+                itor = itor->next;
+        }
+        return NULL;
+}
+
+int
+nubus_find_rsrc(struct nubus_dir* dir, unsigned char rsrc_type,
+                struct nubus_dirent* ent)
+{
+        while (nubus_readdir(dir, ent) != -1) {
+                if (ent->type == rsrc_type)
+                        return 0;
+        }       
+        return -1;
+}
+
+/* Initialization functions - decide which slots contain stuff worth
+   looking at, and print out lots and lots of information from the
+   resource blocks. */
+
+/* FIXME: A lot of this stuff will eventually be useful after
+   initializaton, for intelligently probing Ethernet and video chips,
+   among other things.  The rest of it should go in the /proc code.
+   For now, we just use it to give verbose boot logs. */
+
+static int __init nubus_show_display_resource(struct nubus_dev* dev,
+                                              const struct nubus_dirent* ent)
+{
+        switch (ent->type) {
+        case NUBUS_RESID_GAMMADIR:
+                printk(KERN_INFO "    gamma directory offset: 0x%06x\n", ent->data);
+                break;
+        case 0x0080 ... 0x0085:
+                printk(KERN_INFO "    mode %02X info offset: 0x%06x\n",
+                       ent->type, ent->data);
+                break;
+        default:
+                printk(KERN_INFO "    unknown resource %02X, data 0x%06x\n",
+                       ent->type, ent->data);
+        }
+        return 0;
+}
+
+static int __init nubus_show_network_resource(struct nubus_dev* dev,
+                                              const struct nubus_dirent* ent)
+{
+        switch (ent->type) {
+        case NUBUS_RESID_MAC_ADDRESS:
+        {
+                char addr[6];
+                int i;
+                
+                nubus_get_rsrc_mem(addr, ent, 6);
+                printk(KERN_INFO "    MAC address: ");
+                for (i = 0; i < 6; i++)
+                        printk("%02x%s", addr[i] & 0xff,
+                               i == 5 ? "" : ":");
+                printk("\n");
+                break;
+        }
+        default:
+                printk(KERN_INFO "    unknown resource %02X, data 0x%06x\n",
+                       ent->type, ent->data);
+        }
+        return 0;
+}
+
+static int __init nubus_show_cpu_resource(struct nubus_dev* dev,
+                                          const struct nubus_dirent* ent)
+{
+        switch (ent->type) {
+        case NUBUS_RESID_MEMINFO:
+        {
+                unsigned long meminfo[2];
+                nubus_get_rsrc_mem(&meminfo, ent, 8);
+                printk(KERN_INFO "    memory: [ 0x%08lx 0x%08lx ]\n",
+                       meminfo[0], meminfo[1]);
+                break;
+        }
+        case NUBUS_RESID_ROMINFO:
+        {
+                unsigned long rominfo[2];
+                nubus_get_rsrc_mem(&rominfo, ent, 8);
+                printk(KERN_INFO "    ROM:    [ 0x%08lx 0x%08lx ]\n",
+                       rominfo[0], rominfo[1]);
+                break;
+        }
+        default:
+                printk(KERN_INFO "    unknown resource %02X, data 0x%06x\n",
+                       ent->type, ent->data);
+        }
+        return 0;
+}
+
+static int __init nubus_show_private_resource(struct nubus_dev* dev,
+                                              const struct nubus_dirent* ent)
+{
+        switch (dev->category) {
+        case NUBUS_CAT_DISPLAY:
+                nubus_show_display_resource(dev, ent);
+                break;
+        case NUBUS_CAT_NETWORK:
+                nubus_show_network_resource(dev, ent);
+                break;
+        case NUBUS_CAT_CPU:
+                nubus_show_cpu_resource(dev, ent);
+                break;
+        default:
+                printk(KERN_INFO "    unknown resource %02X, data 0x%06x\n",
+                       ent->type, ent->data);
+        }
+        return 0;
+}
+
+static struct nubus_dev* __init
+           nubus_get_functional_resource(struct nubus_board* board,
+                                         int slot,
+                                         const struct nubus_dirent* parent)
+{
+        struct nubus_dir    dir;
+        struct nubus_dirent ent;
+        struct nubus_dev*   dev;
+        
+        printk(KERN_INFO "  Function 0x%02x:\n", parent->type);
+        nubus_get_subdir(parent, &dir);
+
+        /* Apple seems to have botched the ROM on the IIx */
+        if (slot == 0 && (unsigned long)dir.base % 2)
+                dir.base += 1;
+        
+        if (console_loglevel >= 10)
+                printk(KERN_DEBUG "nubus_get_functional_resource: parent is 0x%p, dir is 0x%p\n",
+                       parent->base, dir.base);
+
+        /* Actually we should probably panic if this fails */
+        if ((dev = kmalloc(sizeof(*dev), GFP_ATOMIC)) == NULL)
+                return NULL;    
+        memset(dev, 0, sizeof(*dev));
+        dev->resid = parent->type;
+        dev->directory = dir.base;
+        dev->board = board;
+        
+        while (nubus_readdir(&dir, &ent) != -1)
+        {
+                switch(ent.type)
+                {
+                case NUBUS_RESID_TYPE:
+                {
+                        unsigned short nbtdata[4];
+                        nubus_get_rsrc_mem(nbtdata, &ent, 8);
+                        dev->category = nbtdata[0];
+                        dev->type     = nbtdata[1];
+                        dev->dr_sw    = nbtdata[2];
+                        dev->dr_hw    = nbtdata[3];
+                        printk(KERN_INFO "    type: [cat 0x%x type 0x%x hw 0x%x sw 0x%x]\n",
+                               nbtdata[0], nbtdata[1], nbtdata[2], nbtdata[3]);
+                        break;
+                }
+                case NUBUS_RESID_NAME:
+                {
+                        nubus_get_rsrc_str(dev->name, &ent, 64);
+                        printk(KERN_INFO "    name: %s\n", dev->name);
+                        break;
+                }
+                case NUBUS_RESID_DRVRDIR:
+                {
+                        /* MacOS driver.  If we were NetBSD we might
+                           use this :-) */
+                        struct nubus_dir drvr_dir;
+                        struct nubus_dirent drvr_ent;
+                        nubus_get_subdir(&ent, &drvr_dir);
+                        nubus_readdir(&drvr_dir, &drvr_ent);
+                        dev->driver = nubus_dirptr(&drvr_ent);
+                        printk(KERN_INFO "    driver at: 0x%p\n",
+                               dev->driver);
+                        break;
+                }
+                case NUBUS_RESID_MINOR_BASEOS:
+                        /* We will need this in order to support
+                           multiple framebuffers.  It might be handy
+                           for Ethernet as well */
+                        nubus_get_rsrc_mem(&dev->iobase, &ent, 4);
+                        printk(KERN_INFO "    memory offset: 0x%08lx\n",
+                               dev->iobase);
+                        break;
+                case NUBUS_RESID_MINOR_LENGTH:
+                        /* Ditto */
+                        nubus_get_rsrc_mem(&dev->iosize, &ent, 4);
+                        printk(KERN_INFO "    memory length: 0x%08lx\n",
+                               dev->iosize);
+                        break;                  
+                case NUBUS_RESID_FLAGS:
+                        dev->flags = ent.data;
+                        printk(KERN_INFO "    flags: 0x%06x\n", dev->flags);
+                        break;
+                case NUBUS_RESID_HWDEVID:
+                        dev->hwdevid = ent.data;
+                        printk(KERN_INFO "    hwdevid: 0x%06x\n", dev->hwdevid);
+                        break;
+                default:
+                        /* Local/Private resources have their own
+                           function */
+                        nubus_show_private_resource(dev, &ent);
+                }
+        }
+                
+        return dev;
+}
+
+/* This is cool. */
+static int __init nubus_get_vidnames(struct nubus_board* board,
+                                     const struct nubus_dirent* parent)
+{
+        struct nubus_dir    dir;
+        struct nubus_dirent ent;
+        /* FIXME: obviously we want to put this in a header file soon */
+        struct vidmode {
+                u32 size;
+                /* Don't know what this is yet */
+                u16 id;
+                /* Longest one I've seen so far is 26 characters */
+                char name[32];
+        };
+
+        printk(KERN_INFO "    video modes supported:\n");
+        nubus_get_subdir(parent, &dir);
+        if (console_loglevel >= 10)
+                printk(KERN_DEBUG "nubus_get_vidnames: parent is 0x%p, dir is 0x%p\n",
+                       parent->base, dir.base);
+
+        while(nubus_readdir(&dir, &ent) != -1)
+        {
+                struct vidmode mode;
+                u32 size;
+
+                /* First get the length */
+                nubus_get_rsrc_mem(&size, &ent, 4);
+                
+                /* Now clobber the whole thing */
+                if (size > sizeof(mode) - 1)
+                        size = sizeof(mode) - 1;
+                memset(&mode, 0, sizeof(mode));
+                nubus_get_rsrc_mem(&mode, &ent, size);
+                printk (KERN_INFO "      %02X: (%02X) %s\n", ent.type,
+                        mode.id, mode.name);
+        }
+        return 0;
+}
+
+/* This is *really* cool. */
+static int __init nubus_get_icon(struct nubus_board* board,
+                                 const struct nubus_dirent* ent)
+{
+        /* Should be 32x32 if my memory serves me correctly */
+        unsigned char icon[128];
+        int x, y;
+        
+        nubus_get_rsrc_mem(&icon, ent, 128);
+        printk(KERN_INFO "    icon:\n");
+
+        /* We should actually plot these somewhere in the framebuffer
+           init.  This is just to demonstrate that they do, in fact,
+           exist */
+        for (y = 0; y < 32; y++) {
+                printk(KERN_INFO "      ");
+                for (x = 0; x < 32; x++) {
+                        if (icon[y*4 + x/8]
+                            & (0x80 >> (x%8)))
+                                printk("*");
+                        else
+                                printk(" ");
+                }
+                printk("\n");
+        }
+        return 0;
+}
+
+static int __init nubus_get_vendorinfo(struct nubus_board* board,
+                                       const struct nubus_dirent* parent)
+{
+        struct nubus_dir    dir;
+        struct nubus_dirent ent;
+        static char* vendor_fields[6] = {"ID", "serial", "revision",
+                                         "part", "date", "unknown field"};
+
+        printk(KERN_INFO "    vendor info:\n");
+        nubus_get_subdir(parent, &dir);
+        if (console_loglevel >= 10)
+                printk(KERN_DEBUG "nubus_get_vendorinfo: parent is 0x%p, dir is 0x%p\n",
+                       parent->base, dir.base);
+
+        while(nubus_readdir(&dir, &ent) != -1)
+        {
+                char name[64];
+                
+                /* These are all strings, we think */
+                nubus_get_rsrc_str(name, &ent, 64);
+                if (ent.type > 5)
+                        ent.type = 5;
+                printk(KERN_INFO "    %s: %s\n",
+                       vendor_fields[ent.type-1], name);
+        }
+        return 0;
+}
+
+static int __init nubus_get_board_resource(struct nubus_board* board, int slot,
+                                           const struct nubus_dirent* parent)
+{
+        struct nubus_dir    dir;
+        struct nubus_dirent ent;
+        
+        nubus_get_subdir(parent, &dir);
+        if (console_loglevel >= 10)
+                printk(KERN_DEBUG "nubus_get_board_resource: parent is 0x%p, dir is 0x%p\n",
+                       parent->base, dir.base);
+
+        while(nubus_readdir(&dir, &ent) != -1)
+        {
+                switch (ent.type) {
+                case NUBUS_RESID_TYPE:
+                {
+                        unsigned short nbtdata[4];
+                        /* This type is always the same, and is not
+                           useful except insofar as it tells us that
+                           we really are looking at a board resource. */
+                        nubus_get_rsrc_mem(nbtdata, &ent, 8);
+                        printk(KERN_INFO "    type: [cat 0x%x type 0x%x hw 0x%x sw 0x%x]\n",
+                               nbtdata[0], nbtdata[1], nbtdata[2],
+                               nbtdata[3]);
+                        if (nbtdata[0] != 1 || nbtdata[1] != 0 ||
+                            nbtdata[2] != 0 || nbtdata[3] != 0)
+                                printk(KERN_ERR "this sResource is not a board resource!\n");
+                        break;
+                }
+                case NUBUS_RESID_NAME:
+                        nubus_get_rsrc_str(board->name, &ent, 64);
+                        printk(KERN_INFO "    name: %s\n", board->name);
+                        break;
+                case NUBUS_RESID_ICON:
+                        nubus_get_icon(board, &ent);
+                        break;
+                case NUBUS_RESID_BOARDID:
+                        printk(KERN_INFO "    board id: 0x%x\n", ent.data);
+                        break;
+                case NUBUS_RESID_PRIMARYINIT:
+                        printk(KERN_INFO "    primary init offset: 0x%06x\n", ent.data);
+                        break;
+                case NUBUS_RESID_VENDORINFO:
+                        nubus_get_vendorinfo(board, &ent);
+                        break;
+                case NUBUS_RESID_FLAGS:
+                        printk(KERN_INFO "    flags: 0x%06x\n", ent.data);
+                        break;
+                case NUBUS_RESID_HWDEVID:
+                        printk(KERN_INFO "    hwdevid: 0x%06x\n", ent.data);
+                        break;
+                case NUBUS_RESID_SECONDINIT:
+                        printk(KERN_INFO "    secondary init offset: 0x%06x\n", ent.data);
+                        break;
+                        /* WTF isn't this in the functional resources? */ 
+                case NUBUS_RESID_VIDNAMES:
+                        nubus_get_vidnames(board, &ent);
+                        break;
+                        /* Same goes for this */
+                case NUBUS_RESID_VIDMODES:
+                        printk(KERN_INFO "    video mode parameter directory offset: 0x%06x\n",
+                               ent.data);
+                        break;                  
+                default:
+                        printk(KERN_INFO "    unknown resource %02X, data 0x%06x\n",
+                               ent.type, ent.data);
+                }
+        }
+        return 0;
+}
+
+/* Attempt to bypass the somewhat non-obvious arrangement of
+   sResources in the motherboard ROM */
+static void __init nubus_find_rom_dir(struct nubus_board* board)
+{
+        unsigned char* rp;
+        unsigned char* romdir;
+        struct nubus_dir dir;
+        struct nubus_dirent ent;
+
+        /* Check for the extra directory just under the format block */
+        rp = board->fblock;
+        nubus_rewind(&rp, 4, board->lanes);
+        if (nubus_get_rom(&rp, 4, board->lanes) != NUBUS_TEST_PATTERN) {
+                /* OK, the ROM was telling the truth */
+                board->directory = board->fblock;
+                nubus_move(&board->directory,
+                           nubus_expand32(board->doffset),
+                           board->lanes);
+                return;
+        }
+
+        /* On "slot zero", you have to walk down a few more
+           directories to get to the equivalent of a real card's root
+           directory.  We don't know what they were smoking when they
+           came up with this. */
+        romdir = nubus_rom_addr(board->slot);
+        nubus_rewind(&romdir, ROM_DIR_OFFSET, board->lanes);
+        dir.base = dir.ptr = romdir;
+        dir.done = 0;
+        dir.mask = board->lanes;
+
+        /* This one points to an "Unknown Macintosh" directory */
+        if (nubus_readdir(&dir, &ent) == -1)
+                goto badrom;
+
+        if (console_loglevel >= 10)
+                printk(KERN_INFO "nubus_get_rom_dir: entry %02x %06x\n", ent.type, ent.data);
+        /* This one takes us to where we want to go. */
+        if (nubus_readdir(&dir, &ent) == -1) 
+                goto badrom;
+        if (console_loglevel >= 10)
+                printk(KERN_DEBUG "nubus_get_rom_dir: entry %02x %06x\n", ent.type, ent.data);
+        nubus_get_subdir(&ent, &dir);
+
+        /* Resource ID 01, also an "Unknown Macintosh" */
+        if (nubus_readdir(&dir, &ent) == -1) 
+                goto badrom;
+        if (console_loglevel >= 10)
+                printk(KERN_DEBUG "nubus_get_rom_dir: entry %02x %06x\n", ent.type, ent.data);
+
+        /* FIXME: the first one is *not* always the right one.  We
+           suspect this has something to do with the ROM revision.
+           "The HORROR ROM" (LC-series) uses 0x7e, while "The HORROR
+           Continues" (Q630) uses 0x7b.  The DAFB Macs evidently use
+           something else.  Please run "Slots" on your Mac (see
+           include/linux/nubus.h for where to get this program) and
+           tell us where the 'SiDirPtr' for Slot 0 is.  If you feel
+           brave, you should also use MacsBug to walk down the ROM
+           directories like this function does and try to find the
+           path to that address... */
+        if (nubus_readdir(&dir, &ent) == -1)
+                goto badrom;
+        if (console_loglevel >= 10)
+                printk(KERN_DEBUG "nubus_get_rom_dir: entry %02x %06x\n", ent.type, ent.data);
+        
+        /* Bwahahahaha... */
+        nubus_get_subdir(&ent, &dir);
+        board->directory = dir.base;
+        return;
+        
+        /* Even more evil laughter... */
+ badrom:
+        board->directory = board->fblock;
+        nubus_move(&board->directory, nubus_expand32(board->doffset), board->lanes);
+        printk(KERN_ERR "nubus_get_rom_dir: ROM weirdness!  Notify the developers...\n");
+}
+
+/* Add a board (might be many devices) to the list */
+static struct nubus_board* __init nubus_add_board(int slot, int bytelanes)
+{
+        struct nubus_board* board;
+        struct nubus_board** boardp;
+
+        unsigned char *rp;
+        unsigned long dpat;
+        struct nubus_dir dir;
+        struct nubus_dirent ent;
+
+        /* Move to the start of the format block */
+        rp = nubus_rom_addr(slot);              
+        nubus_rewind(&rp, FORMAT_BLOCK_SIZE, bytelanes);
+
+        /* Actually we should probably panic if this fails */
+        if ((board = kmalloc(sizeof(*board), GFP_ATOMIC)) == NULL)
+                return NULL;    
+        memset(board, 0, sizeof(*board));
+        board->fblock = rp;
+
+        /* Dump the format block for debugging purposes */
+        if (console_loglevel >= 10) {
+                int i;
+                printk(KERN_DEBUG "Slot %X, format block at 0x%p\n",
+                       slot, rp);
+                printk(KERN_DEBUG "Format block: ");
+                for (i = 0; i < FORMAT_BLOCK_SIZE; i += 4) {
+                        unsigned short foo, bar;
+                        foo = nubus_get_rom(&rp, 2, bytelanes);
+                        bar = nubus_get_rom(&rp, 2, bytelanes);
+                        printk("%04x %04x  ", foo, bar);
+                }
+                printk("\n");
+                rp = board->fblock;
+        }
+        
+        board->slot = slot;
+        board->slot_addr = (unsigned long) nubus_slot_addr(slot);
+        board->doffset = nubus_get_rom(&rp, 4, bytelanes);
+        /* rom_length is *supposed* to be the total length of the
+         * ROM.  In practice it is the "amount of ROM used to compute
+         * the CRC."  So some jokers decide to set it to zero and
+         * set the crc to zero so they don't have to do any math.
+         * See the Performa 460 ROM, for example.  Those Apple "engineers".
+         */
+        board->rom_length = nubus_get_rom(&rp, 4, bytelanes);
+        board->crc = nubus_get_rom(&rp, 4, bytelanes);
+        board->rev = nubus_get_rom(&rp, 1, bytelanes);
+        board->format = nubus_get_rom(&rp,1, bytelanes);
+        board->lanes = bytelanes;
+
+        /* Directory offset should be small and negative... */
+        if(!(board->doffset & 0x00FF0000))
+                printk(KERN_WARNING "Dodgy doffset!\n");
+        dpat = nubus_get_rom(&rp, 4, bytelanes);
+        if(dpat != NUBUS_TEST_PATTERN)
+                printk(KERN_WARNING "Wrong test pattern %08lx!\n", dpat);
+                
+        /*
+         *      I wonder how the CRC is meant to work -
+         *              any takers ?
+         * CSA: According to MAC docs, not all cards pass the CRC anyway,
+         * since the initial Macintosh ROM releases skipped the check.
+         */
+
+        /* Attempt to work around slot zero weirdness */
+        nubus_find_rom_dir(board);
+        nubus_get_root_dir(board, &dir);        
+
+        /* We're ready to rock */
+        printk(KERN_INFO "Slot %X:\n", slot);
+
+        /* Each slot should have one board resource and any number of
+           functional resources.  So we'll fill in some fields in the
+           struct nubus_board from the board resource, then walk down
+           the list of functional resources, spinning out a nubus_dev
+           for each of them. */
+        if (nubus_readdir(&dir, &ent) == -1) {
+                /* We can't have this! */
+                printk(KERN_ERR "Board resource not found!\n");
+                return NULL;
+        } else {
+                printk(KERN_INFO "  Board resource:\n");
+                nubus_get_board_resource(board, slot, &ent);
+        }
+
+        /* Aaaarrrrgghh!  The LC III motherboard has *two* board
+           resources.  I have no idea WTF to do about this. */
+
+        while (nubus_readdir(&dir, &ent) != -1) {
+                struct nubus_dev*  dev;
+                struct nubus_dev** devp;
+                dev = nubus_get_functional_resource(board, slot, &ent);
+                if (dev == NULL)
+                        continue;
+
+                /* We zeroed this out above */
+                if (board->first_dev == NULL)
+                        board->first_dev = dev;
+                
+                /* Put it on the global NuBus device chain. Keep entries in order. */
+                for (devp=&nubus_devices; *devp!=NULL; devp=&((*devp)->next))
+                        /* spin */;
+                *devp = dev;
+                dev->next = NULL;               
+        }
+
+        /* Put it on the global NuBus board chain. Keep entries in order. */
+        for (boardp=&nubus_boards; *boardp!=NULL; boardp=&((*boardp)->next))
+                /* spin */;
+        *boardp = board;
+        board->next = NULL;
+        
+        return board;
+}
+
+void __init nubus_probe_slot(int slot)
+{
+        unsigned char dp;
+        unsigned char* rp;
+        int i;
+
+        rp = nubus_rom_addr(slot);      
+        for(i = 4; i; i--)
+        {
+                unsigned long flags;
+                int card_present;
+
+                rp--;
+                local_irq_save(flags);
+                card_present = hwreg_present(rp);
+                local_irq_restore(flags);
+               
+                if (!card_present)
+                        continue;
+
+                printk(KERN_DEBUG "Now probing slot %X at %p\n", slot, rp);
+                dp = *rp;
+                if(dp == 0)
+                        continue;
+
+                /* The last byte of the format block consists of two
+                   nybbles which are "mirror images" of each other.
+                   These show us the valid bytelanes */
+                if ((((dp>>4) ^ dp) & 0x0F) != 0x0F)
+                        continue;
+                /* Check that this value is actually *on* one of the
+                   bytelanes it claims are valid! */
+                if ((dp & 0x0F) >= (1<<i))
+                        continue;
+
+                /* Looks promising.  Let's put it on the list. */
+                nubus_add_board(slot, dp);
+
+                return;
+        }
+}
+
+#if defined(CONFIG_PROC_FS)
+
+/* /proc/nubus stuff */
+
+static int sprint_nubus_board(struct nubus_board* board, char* ptr, int len)
+{
+        if(len < 100)
+                return -1;
+        
+        sprintf(ptr, "Slot %X: %s\n",
+                board->slot, board->name);
+        
+        return strlen(ptr);
+}
+
+static int nubus_read_proc(char *page, char **start, off_t off,
+                                int count, int *eof, void *data)
+{
+        int nprinted, len, begin = 0;
+        int size = PAGE_SIZE;
+        struct nubus_board* board;
+        
+        len   = sprintf(page, "Nubus devices found:\n");
+        /* Walk the list of NuBus boards */
+        for (board = nubus_boards; board != NULL; board = board->next)
+        {
+                nprinted = sprint_nubus_board(board, page + len, size - len);
+                if (nprinted < 0)
+                        break;
+                len += nprinted;
+                if (len+begin < off) {
+                        begin += len;
+                        len = 0;
+                }
+                if (len+begin >= off+count)
+                        break;
+        }
+        if (len+begin < off)
+                *eof = 1;
+        off -= begin;
+        *start = page + off;
+        len -= off;
+        if (len>count)
+                len = count;
+        if (len<0)
+                len = 0;
+        return len;
+}
+#endif
+
+void __init nubus_scan_bus(void)
+{
+        int slot;
+        /* This might not work on your machine */
+#ifdef I_WANT_TO_PROBE_SLOT_ZERO
+        nubus_probe_slot(0);
+#endif
+        for(slot = 9; slot < 15; slot++)
+        {
+                nubus_probe_slot(slot);
+        }
+}
+
+static int __init nubus_init(void)
+{
+        if (!MACH_IS_MAC) 
+                return 0;
+
+        /* Initialize the NuBus interrupts */
+        if (oss_present) {
+                oss_nubus_init();
+        } else {
+                via_nubus_init();
+        }
+
+#ifdef TRY_TO_DODGE_WSOD
+        /* Rogue Ethernet interrupts can kill the machine if we don't
+           do this.  Obviously this is bogus.  Hopefully the local VIA
+           gurus can fix the real cause of the problem. */
+        mdelay(1000);
+#endif
+        
+        /* And probe */
+        printk("NuBus: Scanning NuBus slots.\n");
+        nubus_devices = NULL;
+        nubus_boards  = NULL;
+        nubus_scan_bus();
+
+#ifdef CONFIG_PROC_FS
+        create_proc_read_entry("nubus", 0, NULL, nubus_read_proc, NULL);
+        nubus_proc_init();
+#endif
+        return 0;
+}
+
+subsys_initcall(nubus_init);