of/fdt: add FDT address translation support

Copy u-boot's FDT address translation code from common/fdt_support. This
code was originally based on the kernel's unflattened DT address parsing
code.

This commit can be reverted once relicensing of this code to GPLv2/BSD
is done and it is added to libfdt.

Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Grant Likely <grant.likely@linaro.org>

3 files changed, 244 insertions, 0 deletions

diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index 9891232f999e..099b1fb00af4 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -1,5 +1,6 @@
 obj-y = base.o device.o platform.o
 obj-$(CONFIG_OF_FLATTREE) += fdt.o
+obj-$(CONFIG_OF_EARLY_FLATTREE) += fdt_address.o
 obj-$(CONFIG_OF_PROMTREE) += pdt.o
 obj-$(CONFIG_OF_ADDRESS)  += address.o
 obj-$(CONFIG_OF_IRQ)    += irq.o
@@ -12,3 +13,4 @@ obj-$(CONFIG_OF_MTD)	+= of_mtd.o
 obj-$(CONFIG_OF_RESERVED_MEM) += of_reserved_mem.o
 
 CFLAGS_fdt.o = -I$(src)/../../scripts/dtc/libfdt
+CFLAGS_fdt_address.o = -I$(src)/../../scripts/dtc/libfdt
diff --git a/drivers/of/fdt_address.c b/drivers/of/fdt_address.c
new file mode 100644
index 000000000000..8d3dc6fbdb7a
--- /dev/null
+++ b/drivers/of/fdt_address.c
@@ -0,0 +1,241 @@
+/*
+ * 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.
+ *
+ * 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, or (at your option)
+ * any later version.
+ */
+#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_debug("\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("FDT: 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("FDT: empty ranges, 1:1 translation\n");
+                goto finish;
+        }
+
+        pr_debug("FDT: 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("FDT: not found !\n");
+                return 1;
+        }
+        memcpy(addr, ranges + na, 4 * pna);
+
+ finish:
+        of_dump_addr("FDT: parent translation for:", addr, pna);
+        pr_debug("FDT: 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
+ */
+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("FDT: ** translation for device %s **\n",
+                 fdt_get_name(blob, node_offset, NULL));
+
+        reg = fdt_getprop(blob, node_offset, "reg", &len);
+        if (!reg) {
+                pr_err("FDT: 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("FDT: Bad cell count for %s\n",
+                       fdt_get_name(blob, node_offset, NULL));
+                goto bail;
+        }
+        memcpy(addr, reg, na * 4);
+
+        pr_debug("FDT: bus (na=%d, ns=%d) on %s\n",
+                 na, ns, fdt_get_name(blob, parent, NULL));
+        of_dump_addr("OF: 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("FDT: 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("FDT: Bad cell count for %s\n",
+                                fdt_get_name(blob, node_offset, NULL));
+                        break;
+                }
+
+                pr_debug("FDT: 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("FDT: one level translation:", addr, na);
+        }
+ bail:
+        return result;
+}
diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index 5c0ab057eecf..05117899fcb4 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -83,6 +83,7 @@ extern void unflatten_device_tree(void);
 extern void unflatten_and_copy_device_tree(void);
 extern void early_init_devtree(void *);
 extern void early_get_first_memblock_info(void *, phys_addr_t *);
+extern u64 fdt_translate_address(const void *blob, int node_offset);
 #else /* CONFIG_OF_FLATTREE */
 static inline void early_init_fdt_scan_reserved_mem(void) {}
 static inline const char *of_flat_dt_get_machine_name(void) { return NULL; }