1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * FDT Address translation based on u-boot fdt_support.c which in turn was
4 * based on the kernel unflattened DT address translation code.
5 *
6 * (C) Copyright 2007
7 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com
8 *
9 * Copyright 2010-2011 Freescale Semiconductor, Inc.
10 */
11
12#define pr_fmt(fmt) "OF: fdt: " fmt
13
14#include <linux/kernel.h>
15#include <linux/libfdt.h>
16#include <linux/of.h>
17#include <linux/of_fdt.h>
18#include <linux/sizes.h>
19
20/* Max address size we deal with */
21#define OF_MAX_ADDR_CELLS 4
22#define OF_CHECK_COUNTS(na, ns) ((na) > 0 && (na) <= OF_MAX_ADDR_CELLS && \
23 (ns) > 0)
24
25/* Debug utility */
26#ifdef DEBUG
27static void __init of_dump_addr(const char *s, const __be32 *addr, int na)
28{
29 pr_debug("%s", s);
30 while(na--)
31 pr_cont(" %08x", *(addr++));
32 pr_cont("\n");
33}
34#else
35static void __init of_dump_addr(const char *s, const __be32 *addr, int na) { }
36#endif
37
38/* Callbacks for bus specific translators */
39struct of_bus {
40 void (*count_cells)(const void *blob, int parentoffset,
41 int *addrc, int *sizec);
42 u64 (*map)(__be32 *addr, const __be32 *range,
43 int na, int ns, int pna);
44 int (*translate)(__be32 *addr, u64 offset, int na);
45};
46
47/* Default translator (generic bus) */
48static void __init fdt_bus_default_count_cells(const void *blob, int parentoffset,
49 int *addrc, int *sizec)
50{
51 const __be32 *prop;
52
53 if (addrc) {
54 prop = fdt_getprop(blob, parentoffset, "#address-cells", NULL);
55 if (prop)
56 *addrc = be32_to_cpup(prop);
57 else
58 *addrc = dt_root_addr_cells;
59 }
60
61 if (sizec) {
62 prop = fdt_getprop(blob, parentoffset, "#size-cells", NULL);
63 if (prop)
64 *sizec = be32_to_cpup(prop);
65 else
66 *sizec = dt_root_size_cells;
67 }
68}
69
70static u64 __init fdt_bus_default_map(__be32 *addr, const __be32 *range,
71 int na, int ns, int pna)
72{
73 u64 cp, s, da;
74
75 cp = of_read_number(range, na);
76 s = of_read_number(range + na + pna, ns);
77 da = of_read_number(addr, na);
78
79 pr_debug("default map, cp=%llx, s=%llx, da=%llx\n",
80 cp, s, da);
81
82 if (da < cp || da >= (cp + s))
83 return OF_BAD_ADDR;
84 return da - cp;
85}
86
87static int __init fdt_bus_default_translate(__be32 *addr, u64 offset, int na)
88{
89 u64 a = of_read_number(addr, na);
90 memset(addr, 0, na * 4);
91 a += offset;
92 if (na > 1)
93 addr[na - 2] = cpu_to_fdt32(a >> 32);
94 addr[na - 1] = cpu_to_fdt32(a & 0xffffffffu);
95
96 return 0;
97}
98
99/* Array of bus specific translators */
100static const struct of_bus of_busses[] __initconst = {
101 /* Default */
102 {
103 .count_cells = fdt_bus_default_count_cells,
104 .map = fdt_bus_default_map,
105 .translate = fdt_bus_default_translate,
106 },
107};
108
109static int __init fdt_translate_one(const void *blob, int parent,
110 const struct of_bus *bus,
111 const struct of_bus *pbus, __be32 *addr,
112 int na, int ns, int pna, const char *rprop)
113{
114 const __be32 *ranges;
115 int rlen;
116 int rone;
117 u64 offset = OF_BAD_ADDR;
118
119 ranges = fdt_getprop(blob, parent, rprop, &rlen);
120 if (!ranges)
121 return 1;
122 if (rlen == 0) {
123 offset = of_read_number(addr, na);
124 memset(addr, 0, pna * 4);
125 pr_debug("empty ranges, 1:1 translation\n");
126 goto finish;
127 }
128
129 pr_debug("walking ranges...\n");
130
131 /* Now walk through the ranges */
132 rlen /= 4;
133 rone = na + pna + ns;
134 for (; rlen >= rone; rlen -= rone, ranges += rone) {
135 offset = bus->map(addr, ranges, na, ns, pna);
136 if (offset != OF_BAD_ADDR)
137 break;
138 }
139 if (offset == OF_BAD_ADDR) {
140 pr_debug("not found !\n");
141 return 1;
142 }
143 memcpy(addr, ranges + na, 4 * pna);
144
145 finish:
146 of_dump_addr("parent translation for:", addr, pna);
147 pr_debug("with offset: %llx\n", offset);
148
149 /* Translate it into parent bus space */
150 return pbus->translate(addr, offset, pna);
151}
152
153/*
154 * Translate an address from the device-tree into a CPU physical address,
155 * this walks up the tree and applies the various bus mappings on the
156 * way.
157 *
158 * Note: We consider that crossing any level with #size-cells == 0 to mean
159 * that translation is impossible (that is we are not dealing with a value
160 * that can be mapped to a cpu physical address). This is not really specified
161 * that way, but this is traditionally the way IBM at least do things
162 */
163static u64 __init fdt_translate_address(const void *blob, int node_offset)
164{
165 int parent, len;
166 const struct of_bus *bus, *pbus;
167 const __be32 *reg;
168 __be32 addr[OF_MAX_ADDR_CELLS];
169 int na, ns, pna, pns;
170 u64 result = OF_BAD_ADDR;
171
172 pr_debug("** translation for device %s **\n",
173 fdt_get_name(blob, node_offset, NULL));
174
175 reg = fdt_getprop(blob, node_offset, "reg", &len);
176 if (!reg) {
177 pr_err("warning: device tree node '%s' has no address.\n",
178 fdt_get_name(blob, node_offset, NULL));
179 goto bail;
180 }
181
182 /* Get parent & match bus type */
183 parent = fdt_parent_offset(blob, node_offset);
184 if (parent < 0)
185 goto bail;
186 bus = &of_busses[0];
187
188 /* Cound address cells & copy address locally */
189 bus->count_cells(blob, parent, &na, &ns);
190 if (!OF_CHECK_COUNTS(na, ns)) {
191 pr_err("Bad cell count for %s\n",
192 fdt_get_name(blob, node_offset, NULL));
193 goto bail;
194 }
195 memcpy(addr, reg, na * 4);
196
197 pr_debug("bus (na=%d, ns=%d) on %s\n",
198 na, ns, fdt_get_name(blob, parent, NULL));
199 of_dump_addr("translating address:", addr, na);
200
201 /* Translate */
202 for (;;) {
203 /* Switch to parent bus */
204 node_offset = parent;
205 parent = fdt_parent_offset(blob, node_offset);
206
207 /* If root, we have finished */
208 if (parent < 0) {
209 pr_debug("reached root node\n");
210 result = of_read_number(addr, na);
211 break;
212 }
213
214 /* Get new parent bus and counts */
215 pbus = &of_busses[0];
216 pbus->count_cells(blob, parent, &pna, &pns);
217 if (!OF_CHECK_COUNTS(pna, pns)) {
218 pr_err("Bad cell count for %s\n",
219 fdt_get_name(blob, node_offset, NULL));
220 break;
221 }
222
223 pr_debug("parent bus (na=%d, ns=%d) on %s\n",
224 pna, pns, fdt_get_name(blob, parent, NULL));
225
226 /* Apply bus translation */
227 if (fdt_translate_one(blob, node_offset, bus, pbus,
228 addr, na, ns, pna, "ranges"))
229 break;
230
231 /* Complete the move up one level */
232 na = pna;
233 ns = pns;
234 bus = pbus;
235
236 of_dump_addr("one level translation:", addr, na);
237 }
238 bail:
239 return result;
240}
241
242/**
243 * of_flat_dt_translate_address - translate DT addr into CPU phys addr
244 * @node: node in the flat blob
245 */
246u64 __init of_flat_dt_translate_address(unsigned long node)
247{
248 return fdt_translate_address(initial_boot_params, node);
249}
250