1 files changed, 249 insertions, 0 deletions
diff --git a/drivers/of/fdt_address.c b/drivers/of/fdt_address.c
new file mode 100644
index 000000000..1dc15ab78
--- /dev/null
+++ b/drivers/of/fdt_address.c
@@ -0,0 +1,249 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * FDT Address translation based on u-boot fdt_support.c which in turn was
+ * based on the kernel unflattened DT address translation code.
+ *
+ * (C) Copyright 2007
+ * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com
+ *
+ * Copyright 2010-2011 Freescale Semiconductor, Inc.
+ */
+
+#define pr_fmt(fmt)	"OF: fdt: " fmt
+
+#include <linux/kernel.h>
+#include <linux/libfdt.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/sizes.h>
+
+/* Max address size we deal with */
+#define OF_MAX_ADDR_CELLS	4
+#define OF_CHECK_COUNTS(na, ns)	((na) > 0 && (na) <= OF_MAX_ADDR_CELLS && \
+			(ns) > 0)
+
+/* Debug utility */
+#ifdef DEBUG
+static void __init of_dump_addr(const char *s, const __be32 *addr, int na)
+{
+	pr_debug("%s", s);
+	while(na--)
+		pr_cont(" %08x", *(addr++));
+	pr_cont("\n");
+}
+#else
+static void __init of_dump_addr(const char *s, const __be32 *addr, int na) { }
+#endif
+
+/* Callbacks for bus specific translators */
+struct of_bus {
+	void		(*count_cells)(const void *blob, int parentoffset,
+				int *addrc, int *sizec);
+	u64		(*map)(__be32 *addr, const __be32 *range,
+				int na, int ns, int pna);
+	int		(*translate)(__be32 *addr, u64 offset, int na);
+};
+
+/* Default translator (generic bus) */
+static void __init fdt_bus_default_count_cells(const void *blob, int parentoffset,
+					       int *addrc, int *sizec)
+{
+	const __be32 *prop;
+
+	if (addrc) {
+		prop = fdt_getprop(blob, parentoffset, "#address-cells", NULL);
+		if (prop)
+			*addrc = be32_to_cpup(prop);
+		else
+			*addrc = dt_root_addr_cells;
+	}
+
+	if (sizec) {
+		prop = fdt_getprop(blob, parentoffset, "#size-cells", NULL);
+		if (prop)
+			*sizec = be32_to_cpup(prop);
+		else
+			*sizec = dt_root_size_cells;
+	}
+}
+
+static u64 __init fdt_bus_default_map(__be32 *addr, const __be32 *range,
+				      int na, int ns, int pna)
+{
+	u64 cp, s, da;
+
+	cp = of_read_number(range, na);
+	s  = of_read_number(range + na + pna, ns);
+	da = of_read_number(addr, na);
+
+	pr_debug("default map, cp=%llx, s=%llx, da=%llx\n",
+	    cp, s, da);
+
+	if (da < cp || da >= (cp + s))
+		return OF_BAD_ADDR;
+	return da - cp;
+}
+
+static int __init fdt_bus_default_translate(__be32 *addr, u64 offset, int na)
+{
+	u64 a = of_read_number(addr, na);
+	memset(addr, 0, na * 4);
+	a += offset;
+	if (na > 1)
+		addr[na - 2] = cpu_to_fdt32(a >> 32);
+	addr[na - 1] = cpu_to_fdt32(a & 0xffffffffu);
+
+	return 0;
+}
+
+/* Array of bus specific translators */
+static const struct of_bus of_busses[] __initconst = {
+	/* Default */
+	{
+		.count_cells = fdt_bus_default_count_cells,
+		.map = fdt_bus_default_map,
+		.translate = fdt_bus_default_translate,
+	},
+};
+
+static int __init fdt_translate_one(const void *blob, int parent,
+				    const struct of_bus *bus,
+				    const struct of_bus *pbus, __be32 *addr,
+				    int na, int ns, int pna, const char *rprop)
+{
+	const __be32 *ranges;
+	int rlen;
+	int rone;
+	u64 offset = OF_BAD_ADDR;
+
+	ranges = fdt_getprop(blob, parent, rprop, &rlen);
+	if (!ranges)
+		return 1;
+	if (rlen == 0) {
+		offset = of_read_number(addr, na);
+		memset(addr, 0, pna * 4);
+		pr_debug("empty ranges, 1:1 translation\n");
+		goto finish;
+	}
+
+	pr_debug("walking ranges...\n");
+
+	/* Now walk through the ranges */
+	rlen /= 4;
+	rone = na + pna + ns;
+	for (; rlen >= rone; rlen -= rone, ranges += rone) {
+		offset = bus->map(addr, ranges, na, ns, pna);
+		if (offset != OF_BAD_ADDR)
+			break;
+	}
+	if (offset == OF_BAD_ADDR) {
+		pr_debug("not found !\n");
+		return 1;
+	}
+	memcpy(addr, ranges + na, 4 * pna);
+
+ finish:
+	of_dump_addr("parent translation for:", addr, pna);
+	pr_debug("with offset: %llx\n", offset);
+
+	/* Translate it into parent bus space */
+	return pbus->translate(addr, offset, pna);
+}
+
+/*
+ * Translate an address from the device-tree into a CPU physical address,
+ * this walks up the tree and applies the various bus mappings on the
+ * way.
+ *
+ * Note: We consider that crossing any level with #size-cells == 0 to mean
+ * that translation is impossible (that is we are not dealing with a value
+ * that can be mapped to a cpu physical address). This is not really specified
+ * that way, but this is traditionally the way IBM at least do things
+ */
+static u64 __init fdt_translate_address(const void *blob, int node_offset)
+{
+	int parent, len;
+	const struct of_bus *bus, *pbus;
+	const __be32 *reg;
+	__be32 addr[OF_MAX_ADDR_CELLS];
+	int na, ns, pna, pns;
+	u64 result = OF_BAD_ADDR;
+
+	pr_debug("** translation for device %s **\n",
+		 fdt_get_name(blob, node_offset, NULL));
+
+	reg = fdt_getprop(blob, node_offset, "reg", &len);
+	if (!reg) {
+		pr_err("warning: device tree node '%s' has no address.\n",
+			fdt_get_name(blob, node_offset, NULL));
+		goto bail;
+	}
+
+	/* Get parent & match bus type */
+	parent = fdt_parent_offset(blob, node_offset);
+	if (parent < 0)
+		goto bail;
+	bus = &of_busses[0];
+
+	/* Cound address cells & copy address locally */
+	bus->count_cells(blob, parent, &na, &ns);
+	if (!OF_CHECK_COUNTS(na, ns)) {
+		pr_err("Bad cell count for %s\n",
+		       fdt_get_name(blob, node_offset, NULL));
+		goto bail;
+	}
+	memcpy(addr, reg, na * 4);
+
+	pr_debug("bus (na=%d, ns=%d) on %s\n",
+		 na, ns, fdt_get_name(blob, parent, NULL));
+	of_dump_addr("translating address:", addr, na);
+
+	/* Translate */
+	for (;;) {
+		/* Switch to parent bus */
+		node_offset = parent;
+		parent = fdt_parent_offset(blob, node_offset);
+
+		/* If root, we have finished */
+		if (parent < 0) {
+			pr_debug("reached root node\n");
+			result = of_read_number(addr, na);
+			break;
+		}
+
+		/* Get new parent bus and counts */
+		pbus = &of_busses[0];
+		pbus->count_cells(blob, parent, &pna, &pns);
+		if (!OF_CHECK_COUNTS(pna, pns)) {
+			pr_err("Bad cell count for %s\n",
+				fdt_get_name(blob, node_offset, NULL));
+			break;
+		}
+
+		pr_debug("parent bus (na=%d, ns=%d) on %s\n",
+			 pna, pns, fdt_get_name(blob, parent, NULL));
+
+		/* Apply bus translation */
+		if (fdt_translate_one(blob, node_offset, bus, pbus,
+					addr, na, ns, pna, "ranges"))
+			break;
+
+		/* Complete the move up one level */
+		na = pna;
+		ns = pns;
+		bus = pbus;
+
+		of_dump_addr("one level translation:", addr, na);
+	}
+ bail:
+	return result;
+}
+
+/**
+ * of_flat_dt_translate_address - translate DT addr into CPU phys addr
+ * @node: node in the flat blob
+ */
+u64 __init of_flat_dt_translate_address(unsigned long node)
+{
+	return fdt_translate_address(initial_boot_params, node);
+}