[PATCH 4/6] of/fdt: add FDT address translation support

Rob Herring
2014-05-08T22:24:06Z

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>
Cc: Grant Likely <grant.likely@linaro.org>
---
drivers/of/Makefile | 2 +
drivers/of/fdt_address.c | 241 +++++++++++++++++++++++++++++++++++++++++++++++
include/linux/of_fdt.h | 1 +
3 files changed, 244 insertions(+)
create mode 100644 drivers/of/fdt_address.c

diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index 9891232..099b1fb 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 0000000..8d3dc6f
--- /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 5c0ab05..0511789 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; }
--
1.9.1