[SPARC]: Port sparc64 in-kernel device tree code to sparc32.

Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 563 insertions, 82 deletions

diff --git a/arch/sparc/kernel/Makefile b/arch/sparc/kernel/Makefile
index 1b83e21841b5..93e41d0dd8da 100644
--- a/arch/sparc/kernel/Makefile
+++ b/arch/sparc/kernel/Makefile
@@ -12,7 +12,7 @@ obj-y    := entry.o wof.o wuf.o etrap.o rtrap.o traps.o $(IRQ_OBJS) \
 	    sys_sparc.o sunos_asm.o systbls.o \
 	    time.o windows.o cpu.o devices.o sclow.o \
 	    tadpole.o tick14.o ptrace.o sys_solaris.o \
-	    unaligned.o muldiv.o semaphore.o
+	    unaligned.o muldiv.o semaphore.o prom.o
 
 obj-$(CONFIG_PCI) += pcic.o
 obj-$(CONFIG_SUN4) += sun4setup.o
diff --git a/arch/sparc/kernel/ebus.c b/arch/sparc/kernel/ebus.c
index 5c3529ceb5d6..9d461da76399 100644
--- a/arch/sparc/kernel/ebus.c
+++ b/arch/sparc/kernel/ebus.c
@@ -20,6 +20,7 @@
 #include <asm/ebus.h>
 #include <asm/io.h>
 #include <asm/oplib.h>
+#include <asm/prom.h>
 #include <asm/bpp.h>
 
 struct linux_ebus *ebus_chain = NULL;
@@ -83,79 +84,81 @@ int __init ebus_blacklist_irq(char *name)
 	return 0;
 }
 
-void __init fill_ebus_child(int node, struct linux_prom_registers *preg,
-				struct linux_ebus_child *dev)
+void __init fill_ebus_child(struct device_node *dp,
+			    struct linux_ebus_child *dev)
 {
-	int regs[PROMREG_MAX];
-	int irqs[PROMREG_MAX];
-	char lbuf[128];
+	int *regs;
+	int *irqs;
 	int i, len;
 
-	dev->prom_node = node;
-	prom_getstring(node, "name", lbuf, sizeof(lbuf));
-	strcpy(dev->prom_name, lbuf);
-
-	len = prom_getproperty(node, "reg", (void *)regs, sizeof(regs));
-	if (len == -1) len = 0;
+	dev->prom_node = dp;
+	regs = of_get_property(dp, "reg", &len);
+	if (!regs)
+		len = 0;
 	dev->num_addrs = len / sizeof(regs[0]);
 
 	for (i = 0; i < dev->num_addrs; i++) {
 		if (regs[i] >= dev->parent->num_addrs) {
 			prom_printf("UGH: property for %s was %d, need < %d\n",
-				    dev->prom_name, len, dev->parent->num_addrs);
+				    dev->prom_node->name, len,
+				    dev->parent->num_addrs);
 			panic(__FUNCTION__);
 		}
-		dev->resource[i].start = dev->parent->resource[regs[i]].start; /* XXX resource */
+
+		/* XXX resource */
+		dev->resource[i].start =
+			dev->parent->resource[regs[i]].start;
 	}
 
 	for (i = 0; i < PROMINTR_MAX; i++)
 		dev->irqs[i] = PCI_IRQ_NONE;
 
-	if ((dev->irqs[0] = ebus_blacklist_irq(dev->prom_name)) != 0) {
+	if ((dev->irqs[0] = ebus_blacklist_irq(dev->prom_node->name)) != 0) {
 		dev->num_irqs = 1;
-	} else if ((len = prom_getproperty(node, "interrupts",
-	    (char *)&irqs, sizeof(irqs))) == -1 || len == 0) {
-		dev->num_irqs = 0;
-		dev->irqs[0] = 0;
-		if (dev->parent->num_irqs != 0) {
-			dev->num_irqs = 1;
-			dev->irqs[0] = dev->parent->irqs[0];
-/* P3 */ /* printk("EBUS: dev %s irq %d from parent\n", dev->prom_name, dev->irqs[0]); */
-		}
 	} else {
-		dev->num_irqs = len / sizeof(irqs[0]);
-		if (irqs[0] == 0 || irqs[0] >= 8) {
-			/*
-			 * XXX Zero is a valid pin number...
-			 * This works as long as Ebus is not wired to INTA#.
-			 */
-			printk("EBUS: %s got bad irq %d from PROM\n",
-			    dev->prom_name, irqs[0]);
+		irqs = of_get_property(dp, "interrupts", &len);
+		if (!irqs) {
 			dev->num_irqs = 0;
 			dev->irqs[0] = 0;
+			if (dev->parent->num_irqs != 0) {
+				dev->num_irqs = 1;
+				dev->irqs[0] = dev->parent->irqs[0];
+			}
 		} else {
-			dev->irqs[0] = pcic_pin_to_irq(irqs[0], dev->prom_name);
+			dev->num_irqs = len / sizeof(irqs[0]);
+			if (irqs[0] == 0 || irqs[0] >= 8) {
+				/*
+				 * XXX Zero is a valid pin number...
+				 * This works as long as Ebus is not wired
+				 * to INTA#.
+				 */
+				printk("EBUS: %s got bad irq %d from PROM\n",
+				       dev->prom_node->name, irqs[0]);
+				dev->num_irqs = 0;
+				dev->irqs[0] = 0;
+			} else {
+				dev->irqs[0] =
+					pcic_pin_to_irq(irqs[0],
+							dev->prom_node->name);
+			}
 		}
 	}
 }
 
-void __init fill_ebus_device(int node, struct linux_ebus_device *dev)
+void __init fill_ebus_device(struct device_node *dp, struct linux_ebus_device *dev)
 {
-	struct linux_prom_registers regs[PROMREG_MAX];
+	struct linux_prom_registers *regs;
 	struct linux_ebus_child *child;
-	int irqs[PROMINTR_MAX];
-	char lbuf[128];
+	int *irqs;
 	int i, n, len;
 	unsigned long baseaddr;
 
-	dev->prom_node = node;
-	prom_getstring(node, "name", lbuf, sizeof(lbuf));
-	strcpy(dev->prom_name, lbuf);
+	dev->prom_node = dp;
 
-	len = prom_getproperty(node, "reg", (void *)regs, sizeof(regs));
+	regs = of_get_property(dp, "reg", &len);
 	if (len % sizeof(struct linux_prom_registers)) {
 		prom_printf("UGH: proplen for %s was %d, need multiple of %d\n",
-			    dev->prom_name, len,
+			    dev->prom_node->name, len,
 			    (int)sizeof(struct linux_prom_registers));
 		panic(__FUNCTION__);
 	}
@@ -197,7 +200,7 @@ void __init fill_ebus_device(int node, struct linux_ebus_device *dev)
 			if ((baseaddr = (unsigned long) ioremap(baseaddr,
 			    regs[i].reg_size)) == 0) {
 				panic("ebus: unable to remap dev %s",
-				    dev->prom_name);
+				      dev->prom_node->name);
 			}
 		}
 		dev->resource[i].start = baseaddr;	/* XXX Unaligned */
@@ -206,29 +209,33 @@ void __init fill_ebus_device(int node, struct linux_ebus_device *dev)
 	for (i = 0; i < PROMINTR_MAX; i++)
 		dev->irqs[i] = PCI_IRQ_NONE;
 
-	if ((dev->irqs[0] = ebus_blacklist_irq(dev->prom_name)) != 0) {
+	if ((dev->irqs[0] = ebus_blacklist_irq(dev->prom_node->name)) != 0) {
 		dev->num_irqs = 1;
-	} else if ((len = prom_getproperty(node, "interrupts",
-	    (char *)&irqs, sizeof(irqs))) == -1 || len == 0) {
-		dev->num_irqs = 0;
-		if ((dev->irqs[0] = dev->bus->self->irq) != 0) {
-			 dev->num_irqs = 1;
-/* P3 */ /* printk("EBUS: child %s irq %d from parent\n", dev->prom_name, dev->irqs[0]); */
-		}
 	} else {
-		dev->num_irqs = 1;  /* dev->num_irqs = len / sizeof(irqs[0]); */
-		if (irqs[0] == 0 || irqs[0] >= 8) {
-			/* See above for the parent. XXX */
-			printk("EBUS: %s got bad irq %d from PROM\n",
-			    dev->prom_name, irqs[0]);
+		irqs = of_get_property(dp, "interrupts", &len);
+		if (!irqs) {
 			dev->num_irqs = 0;
-			dev->irqs[0] = 0;
+			if ((dev->irqs[0] = dev->bus->self->irq) != 0) {
+				dev->num_irqs = 1;
+/* P3 */ /* printk("EBUS: child %s irq %d from parent\n", dev->prom_name, dev->irqs[0]); */
+			}
 		} else {
-			dev->irqs[0] = pcic_pin_to_irq(irqs[0], dev->prom_name);
+			dev->num_irqs = 1;  /* dev->num_irqs = len / sizeof(irqs[0]); */
+			if (irqs[0] == 0 || irqs[0] >= 8) {
+				/* See above for the parent. XXX */
+				printk("EBUS: %s got bad irq %d from PROM\n",
+				       dev->prom_node->name, irqs[0]);
+				dev->num_irqs = 0;
+				dev->irqs[0] = 0;
+			} else {
+				dev->irqs[0] =
+					pcic_pin_to_irq(irqs[0],
+							dev->prom_node->name);
+			}
 		}
 	}
 
-	if ((node = prom_getchild(node))) {
+	if ((dp = dp->child) != NULL) {
 		dev->children = (struct linux_ebus_child *)
 			ebus_alloc(sizeof(struct linux_ebus_child));
 
@@ -236,9 +243,9 @@ void __init fill_ebus_device(int node, struct linux_ebus_device *dev)
 		child->next = NULL;
 		child->parent = dev;
 		child->bus = dev->bus;
-		fill_ebus_child(node, &regs[0], child);
+		fill_ebus_child(dp, child);
 
-		while ((node = prom_getsibling(node)) != 0) {
+		while ((dp = dp->sibling) != NULL) {
 			child->next = (struct linux_ebus_child *)
 				ebus_alloc(sizeof(struct linux_ebus_child));
 
@@ -246,51 +253,49 @@ void __init fill_ebus_device(int node, struct linux_ebus_device *dev)
 			child->next = NULL;
 			child->parent = dev;
 			child->bus = dev->bus;
-			fill_ebus_child(node, &regs[0], child);
+			fill_ebus_child(dp, child);
 		}
 	}
 }
 
 void __init ebus_init(void)
 {
-	struct linux_prom_pci_registers regs[PROMREG_MAX];
+	struct linux_prom_pci_registers *regs;
 	struct linux_pbm_info *pbm;
 	struct linux_ebus_device *dev;
 	struct linux_ebus *ebus;
 	struct ebus_system_entry *sp;
 	struct pci_dev *pdev;
 	struct pcidev_cookie *cookie;
-	char lbuf[128];
+	struct device_node *dp;
 	unsigned long addr, *base;
 	unsigned short pci_command;
-	int nd, len, ebusnd;
-	int reg, nreg;
+	int len, reg, nreg;
 	int num_ebus = 0;
 
-	prom_getstring(prom_root_node, "name", lbuf, sizeof(lbuf));
+	dp = of_find_node_by_path("/");
 	for (sp = ebus_blacklist; sp->esname != NULL; sp++) {
-		if (strcmp(lbuf, sp->esname) == 0) {
+		if (strcmp(dp->name, sp->esname) == 0) {
 			ebus_blackp = sp->ipt;
 			break;
 		}
 	}
 
 	pdev = pci_get_device(PCI_VENDOR_ID_SUN, PCI_DEVICE_ID_SUN_EBUS, NULL);
-	if (!pdev) {
+	if (!pdev)
 		return;
-	}
+
 	cookie = pdev->sysdata;
-	ebusnd = cookie->prom_node;
+	dp = cookie->prom_node;
 
 	ebus_chain = ebus = (struct linux_ebus *)
 			ebus_alloc(sizeof(struct linux_ebus));
 	ebus->next = NULL;
 
-	while (ebusnd) {
+	while (dp) {
+		struct device_node *nd;
 
-		prom_getstring(ebusnd, "name", lbuf, sizeof(lbuf));
-		ebus->prom_node = ebusnd;
-		strcpy(ebus->prom_name, lbuf);
+		ebus->prom_node = dp;
 		ebus->self = pdev;
 		ebus->parent = pbm = cookie->pbm;
 
@@ -299,9 +304,8 @@ void __init ebus_init(void)
 		pci_command |= PCI_COMMAND_MASTER;
 		pci_write_config_word(pdev, PCI_COMMAND, pci_command);
 
-		len = prom_getproperty(ebusnd, "reg", (void *)regs,
-				       sizeof(regs));
-		if (len == 0 || len == -1) {
+		regs = of_get_property(dp, "reg", &len);
+		if (!regs) {
 			prom_printf("%s: can't find reg property\n",
 				    __FUNCTION__);
 			prom_halt();
@@ -317,7 +321,7 @@ void __init ebus_init(void)
 			*base++ = addr;
 		}
 
-		nd = prom_getchild(ebusnd);
+		nd = dp->child;
 		if (!nd)
 			goto next_ebus;
 
@@ -330,7 +334,7 @@ void __init ebus_init(void)
 		dev->bus = ebus;
 		fill_ebus_device(nd, dev);
 
-		while ((nd = prom_getsibling(nd)) != 0) {
+		while ((nd = nd->sibling) != NULL) {
 			dev->next = (struct linux_ebus_device *)
 				ebus_alloc(sizeof(struct linux_ebus_device));
 
@@ -348,7 +352,7 @@ void __init ebus_init(void)
 			break;
 
 		cookie = pdev->sysdata;
-		ebusnd = cookie->prom_node;
+		dp = cookie->prom_node;
 
 		ebus->next = (struct linux_ebus *)
 			ebus_alloc(sizeof(struct linux_ebus));
diff --git a/arch/sparc/kernel/pcic.c b/arch/sparc/kernel/pcic.c
index bcdf5ad0f035..bcfdddd0418a 100644
--- a/arch/sparc/kernel/pcic.c
+++ b/arch/sparc/kernel/pcic.c
@@ -31,6 +31,7 @@
 
 #include <asm/irq.h>
 #include <asm/oplib.h>
+#include <asm/prom.h>
 #include <asm/pcic.h>
 #include <asm/timer.h>
 #include <asm/uaccess.h>
@@ -665,7 +666,7 @@ void __init pcibios_fixup_bus(struct pci_bus *bus)
 		/* cookies */
 		pcp = pci_devcookie_alloc();
 		pcp->pbm = &pcic->pbm;
-		pcp->prom_node = node;
+		pcp->prom_node = of_find_node_by_phandle(node);
 		dev->sysdata = pcp;
 
 		/* fixing I/O to look like memory */
diff --git a/arch/sparc/kernel/prom.c b/arch/sparc/kernel/prom.c
new file mode 100644
index 000000000000..63b2b9bd778e
--- /dev/null
+++ b/arch/sparc/kernel/prom.c
@@ -0,0 +1,474 @@
+/*
+ * Procedures for creating, accessing and interpreting the device tree.
+ *
+ * Paul Mackerras	August 1996.
+ * Copyright (C) 1996-2005 Paul Mackerras.
+ * 
+ *  Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
+ *    {engebret|bergner}@us.ibm.com 
+ *
+ *  Adapted for sparc32 by David S. Miller davem@davemloft.net
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/bootmem.h>
+#include <linux/module.h>
+
+#include <asm/prom.h>
+#include <asm/oplib.h>
+
+static struct device_node *allnodes;
+
+int of_device_is_compatible(struct device_node *device, const char *compat)
+{
+	const char* cp;
+	int cplen, l;
+
+	cp = (char *) of_get_property(device, "compatible", &cplen);
+	if (cp == NULL)
+		return 0;
+	while (cplen > 0) {
+		if (strncmp(cp, compat, strlen(compat)) == 0)
+			return 1;
+		l = strlen(cp) + 1;
+		cp += l;
+		cplen -= l;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(of_device_is_compatible);
+
+struct device_node *of_get_parent(const struct device_node *node)
+{
+	struct device_node *np;
+
+	if (!node)
+		return NULL;
+
+	np = node->parent;
+
+	return np;
+}
+EXPORT_SYMBOL(of_get_parent);
+
+struct device_node *of_get_next_child(const struct device_node *node,
+	struct device_node *prev)
+{
+	struct device_node *next;
+
+	next = prev ? prev->sibling : node->child;
+	for (; next != 0; next = next->sibling) {
+		break;
+	}
+
+	return next;
+}
+EXPORT_SYMBOL(of_get_next_child);
+
+struct device_node *of_find_node_by_path(const char *path)
+{
+	struct device_node *np = allnodes;
+
+	for (; np != 0; np = np->allnext) {
+		if (np->full_name != 0 && strcmp(np->full_name, path) == 0)
+			break;
+	}
+
+	return np;
+}
+EXPORT_SYMBOL(of_find_node_by_path);
+
+struct device_node *of_find_node_by_phandle(phandle handle)
+{
+	struct device_node *np;
+
+	for (np = allnodes; np != 0; np = np->allnext)
+		if (np->node == handle)
+			break;
+
+	return np;
+}
+EXPORT_SYMBOL(of_find_node_by_phandle);
+
+struct device_node *of_find_node_by_name(struct device_node *from,
+	const char *name)
+{
+	struct device_node *np;
+
+	np = from ? from->allnext : allnodes;
+	for (; np != NULL; np = np->allnext)
+		if (np->name != NULL && strcmp(np->name, name) == 0)
+			break;
+
+	return np;
+}
+EXPORT_SYMBOL(of_find_node_by_name);
+
+struct device_node *of_find_node_by_type(struct device_node *from,
+	const char *type)
+{
+	struct device_node *np;
+
+	np = from ? from->allnext : allnodes;
+	for (; np != 0; np = np->allnext)
+		if (np->type != 0 && strcmp(np->type, type) == 0)
+			break;
+
+	return np;
+}
+EXPORT_SYMBOL(of_find_node_by_type);
+
+struct device_node *of_find_compatible_node(struct device_node *from,
+	const char *type, const char *compatible)
+{
+	struct device_node *np;
+
+	np = from ? from->allnext : allnodes;
+	for (; np != 0; np = np->allnext) {
+		if (type != NULL
+		    && !(np->type != 0 && strcmp(np->type, type) == 0))
+			continue;
+		if (of_device_is_compatible(np, compatible))
+			break;
+	}
+
+	return np;
+}
+EXPORT_SYMBOL(of_find_compatible_node);
+
+struct property *of_find_property(struct device_node *np, const char *name,
+				  int *lenp)
+{
+	struct property *pp;
+
+	for (pp = np->properties; pp != 0; pp = pp->next) {
+		if (strcmp(pp->name, name) == 0) {
+			if (lenp != 0)
+				*lenp = pp->length;
+			break;
+		}
+	}
+	return pp;
+}
+EXPORT_SYMBOL(of_find_property);
+
+/*
+ * Find a property with a given name for a given node
+ * and return the value.
+ */
+void *of_get_property(struct device_node *np, const char *name, int *lenp)
+{
+	struct property *pp = of_find_property(np,name,lenp);
+	return pp ? pp->value : NULL;
+}
+EXPORT_SYMBOL(of_get_property);
+
+int of_getintprop_default(struct device_node *np, const char *name, int def)
+{
+	struct property *prop;
+	int len;
+
+	prop = of_find_property(np, name, &len);
+	if (!prop || len != 4)
+		return def;
+
+	return *(int *) prop->value;
+}
+EXPORT_SYMBOL(of_getintprop_default);
+
+static unsigned int prom_early_allocated;
+
+static void * __init prom_early_alloc(unsigned long size)
+{
+	void *ret;
+
+	ret = __alloc_bootmem(size, SMP_CACHE_BYTES, 0UL);
+	if (ret != NULL)
+		memset(ret, 0, size);
+
+	prom_early_allocated += size;
+
+	return ret;
+}
+
+static int is_root_node(const struct device_node *dp)
+{
+	if (!dp)
+		return 0;
+
+	return (dp->parent == NULL);
+}
+
+/* The following routines deal with the black magic of fully naming a
+ * node.
+ *
+ * Certain well known named nodes are just the simple name string.
+ *
+ * Actual devices have an address specifier appended to the base name
+ * string, like this "foo@addr".  The "addr" can be in any number of
+ * formats, and the platform plus the type of the node determine the
+ * format and how it is constructed.
+ *
+ * For children of the ROOT node, the naming convention is fixed and
+ * determined by whether this is a sun4u or sun4v system.
+ *
+ * For children of other nodes, it is bus type specific.  So
+ * we walk up the tree until we discover a "device_type" property
+ * we recognize and we go from there.
+ */
+static void __init sparc32_path_component(struct device_node *dp, char *tmp_buf)
+{
+	struct linux_prom_registers *regs;
+	struct property *rprop;
+
+	rprop = of_find_property(dp, "reg", NULL);
+	if (!rprop)
+		return;
+
+	regs = rprop->value;
+	sprintf(tmp_buf, "%s@%x,%x",
+		dp->name,
+		regs->which_io, regs->phys_addr);
+}
+
+/* "name@slot,offset"  */
+static void __init sbus_path_component(struct device_node *dp, char *tmp_buf)
+{
+	struct linux_prom_registers *regs;
+	struct property *prop;
+
+	prop = of_find_property(dp, "reg", NULL);
+	if (!prop)
+		return;
+
+	regs = prop->value;
+	sprintf(tmp_buf, "%s@%x,%x",
+		dp->name,
+		regs->which_io,
+		regs->phys_addr);
+}
+
+/* "name@devnum[,func]" */
+static void __init pci_path_component(struct device_node *dp, char *tmp_buf)
+{
+	struct linux_prom_pci_registers *regs;
+	struct property *prop;
+	unsigned int devfn;
+
+	prop = of_find_property(dp, "reg", NULL);
+	if (!prop)
+		return;
+
+	regs = prop->value;
+	devfn = (regs->phys_hi >> 8) & 0xff;
+	if (devfn & 0x07) {
+		sprintf(tmp_buf, "%s@%x,%x",
+			dp->name,
+			devfn >> 3,
+			devfn & 0x07);
+	} else {
+		sprintf(tmp_buf, "%s@%x",
+			dp->name,
+			devfn >> 3);
+	}
+}
+
+/* "name@addrhi,addrlo" */
+static void __init ebus_path_component(struct device_node *dp, char *tmp_buf)
+{
+	struct linux_prom_registers *regs;
+	struct property *prop;
+
+	prop = of_find_property(dp, "reg", NULL);
+	if (!prop)
+		return;
+
+	regs = prop->value;
+
+	sprintf(tmp_buf, "%s@%x,%x",
+		dp->name,
+		regs->which_io, regs->phys_addr);
+}
+
+static void __init __build_path_component(struct device_node *dp, char *tmp_buf)
+{
+	struct device_node *parent = dp->parent;
+
+	if (parent != NULL) {
+		if (!strcmp(parent->type, "pci") ||
+		    !strcmp(parent->type, "pciex"))
+			return pci_path_component(dp, tmp_buf);
+		if (!strcmp(parent->type, "sbus"))
+			return sbus_path_component(dp, tmp_buf);
+		if (!strcmp(parent->type, "ebus"))
+			return ebus_path_component(dp, tmp_buf);
+
+		/* "isa" is handled with platform naming */
+	}
+
+	/* Use platform naming convention.  */
+	return sparc32_path_component(dp, tmp_buf);
+}
+
+static char * __init build_path_component(struct device_node *dp)
+{
+	char tmp_buf[64], *n;
+
+	tmp_buf[0] = '\0';
+	__build_path_component(dp, tmp_buf);
+	if (tmp_buf[0] == '\0')
+		strcpy(tmp_buf, dp->name);
+
+	n = prom_early_alloc(strlen(tmp_buf) + 1);
+	strcpy(n, tmp_buf);
+
+	return n;
+}
+
+static char * __init build_full_name(struct device_node *dp)
+{
+	int len, ourlen, plen;
+	char *n;
+
+	plen = strlen(dp->parent->full_name);
+	ourlen = strlen(dp->path_component_name);
+	len = ourlen + plen + 2;
+
+	n = prom_early_alloc(len);
+	strcpy(n, dp->parent->full_name);
+	if (!is_root_node(dp->parent)) {
+		strcpy(n + plen, "/");
+		plen++;
+	}
+	strcpy(n + plen, dp->path_component_name);
+
+	return n;
+}
+
+static struct property * __init build_one_prop(phandle node, char *prev)
+{
+	static struct property *tmp = NULL;
+	struct property *p;
+	int len;
+
+	if (tmp) {
+		p = tmp;
+		memset(p, 0, sizeof(*p) + 32);
+		tmp = NULL;
+	} else
+		p = prom_early_alloc(sizeof(struct property) + 32);
+
+	p->name = (char *) (p + 1);
+	if (prev == NULL) {
+		prom_firstprop(node, p->name);
+	} else {
+		prom_nextprop(node, prev, p->name);
+	}
+	if (strlen(p->name) == 0) {
+		tmp = p;
+		return NULL;
+	}
+	p->length = prom_getproplen(node, p->name);
+	if (p->length <= 0) {
+		p->length = 0;
+	} else {
+		p->value = prom_early_alloc(p->length);
+		len = prom_getproperty(node, p->name, p->value, p->length);
+	}
+	return p;
+}
+
+static struct property * __init build_prop_list(phandle node)
+{
+	struct property *head, *tail;
+
+	head = tail = build_one_prop(node, NULL);
+	while(tail) {
+		tail->next = build_one_prop(node, tail->name);
+		tail = tail->next;
+	}
+
+	return head;
+}
+
+static char * __init get_one_property(phandle node, char *name)
+{
+	char *buf = "<NULL>";
+	int len;
+
+	len = prom_getproplen(node, name);
+	if (len > 0) {
+		buf = prom_early_alloc(len);
+		len = prom_getproperty(node, name, buf, len);
+	}
+
+	return buf;
+}
+
+static struct device_node * __init create_node(phandle node)
+{
+	struct device_node *dp;
+
+	if (!node)
+		return NULL;
+
+	dp = prom_early_alloc(sizeof(*dp));
+
+	kref_init(&dp->kref);
+
+	dp->name = get_one_property(node, "name");
+	dp->type = get_one_property(node, "device_type");
+	dp->node = node;
+
+	/* Build interrupts later... */
+
+	dp->properties = build_prop_list(node);
+
+	return dp;
+}
+
+static struct device_node * __init build_tree(struct device_node *parent, phandle node, struct device_node ***nextp)
+{
+	struct device_node *dp;
+
+	dp = create_node(node);
+	if (dp) {
+		*(*nextp) = dp;
+		*nextp = &dp->allnext;
+
+		dp->parent = parent;
+		dp->path_component_name = build_path_component(dp);
+		dp->full_name = build_full_name(dp);
+
+		dp->child = build_tree(dp, prom_getchild(node), nextp);
+
+		dp->sibling = build_tree(parent, prom_getsibling(node), nextp);
+	}
+
+	return dp;
+}
+
+void __init prom_build_devicetree(void)
+{
+	struct device_node **nextp;
+
+	allnodes = create_node(prom_root_node);
+	allnodes->path_component_name = "";
+	allnodes->full_name = "/";
+
+	nextp = &allnodes->allnext;
+	allnodes->child = build_tree(allnodes,
+				     prom_getchild(allnodes->node),
+				     &nextp);
+	printk("PROM: Built device tree with %u bytes of memory.\n",
+	       prom_early_allocated);
+}
diff --git a/arch/sparc/mm/init.c b/arch/sparc/mm/init.c
index 898669732466..cfa7d3456634 100644
--- a/arch/sparc/mm/init.c
+++ b/arch/sparc/mm/init.c
@@ -31,6 +31,7 @@
 #include <asm/vaddrs.h>
 #include <asm/pgalloc.h>	/* bug in asm-generic/tlb.h: check_pgt_cache */
 #include <asm/tlb.h>
+#include <asm/prom.h>
 
 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
 
@@ -349,6 +350,7 @@ void __init paging_init(void)
 	protection_map[14] = PAGE_SHARED;
 	protection_map[15] = PAGE_SHARED;
 	btfixup();
+	prom_build_devicetree();
 	device_scan();
 }