1 /*
2 * linux/arch/arm/kernel/devtree.c
3 *
4 * Copyright (C) 2009 Canonical Ltd. <jeremy.kerr@canonical.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11 #include <linux/init.h>
12 #include <linux/export.h>
13 #include <linux/errno.h>
14 #include <linux/types.h>
15 #include <linux/bootmem.h>
16 #include <linux/memblock.h>
17 #include <linux/of.h>
18 #include <linux/of_fdt.h>
19 #include <linux/of_irq.h>
20 #include <linux/of_platform.h>
21 #include <linux/smp.h>
22
23 #include <asm/cputype.h>
24 #include <asm/setup.h>
25 #include <asm/page.h>
26 #include <asm/prom.h>
27 #include <asm/smp_plat.h>
28 #include <asm/mach/arch.h>
29 #include <asm/mach-types.h>
30
31
32 #ifdef CONFIG_SMP
33 extern struct of_cpu_method __cpu_method_of_table[];
34
35 static const struct of_cpu_method __cpu_method_of_table_sentinel
36 __used __section(__cpu_method_of_table_end);
37
38
set_smp_ops_by_method(struct device_node * node)39 static int __init set_smp_ops_by_method(struct device_node *node)
40 {
41 const char *method;
42 struct of_cpu_method *m = __cpu_method_of_table;
43
44 if (of_property_read_string(node, "enable-method", &method))
45 return 0;
46
47 for (; m->method; m++)
48 if (!strcmp(m->method, method)) {
49 smp_set_ops(m->ops);
50 return 1;
51 }
52
53 return 0;
54 }
55 #else
set_smp_ops_by_method(struct device_node * node)56 static inline int set_smp_ops_by_method(struct device_node *node)
57 {
58 return 1;
59 }
60 #endif
61
62
63 /*
64 * arm_dt_init_cpu_maps - Function retrieves cpu nodes from the device tree
65 * and builds the cpu logical map array containing MPIDR values related to
66 * logical cpus
67 *
68 * Updates the cpu possible mask with the number of parsed cpu nodes
69 */
arm_dt_init_cpu_maps(void)70 void __init arm_dt_init_cpu_maps(void)
71 {
72 /*
73 * Temp logical map is initialized with UINT_MAX values that are
74 * considered invalid logical map entries since the logical map must
75 * contain a list of MPIDR[23:0] values where MPIDR[31:24] must
76 * read as 0.
77 */
78 struct device_node *cpu, *cpus;
79 int found_method = 0;
80 u32 i, j, cpuidx = 1;
81 u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
82
83 u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
84 bool bootcpu_valid = false;
85 cpus = of_find_node_by_path("/cpus");
86
87 if (!cpus)
88 return;
89
90 for_each_child_of_node(cpus, cpu) {
91 const __be32 *cell;
92 int prop_bytes;
93 u32 hwid;
94
95 if (of_node_cmp(cpu->type, "cpu"))
96 continue;
97
98 pr_debug(" * %pOF...\n", cpu);
99 /*
100 * A device tree containing CPU nodes with missing "reg"
101 * properties is considered invalid to build the
102 * cpu_logical_map.
103 */
104 cell = of_get_property(cpu, "reg", &prop_bytes);
105 if (!cell || prop_bytes < sizeof(*cell)) {
106 pr_debug(" * %pOF missing reg property\n", cpu);
107 of_node_put(cpu);
108 return;
109 }
110
111 /*
112 * Bits n:24 must be set to 0 in the DT since the reg property
113 * defines the MPIDR[23:0].
114 */
115 do {
116 hwid = be32_to_cpu(*cell++);
117 prop_bytes -= sizeof(*cell);
118 } while (!hwid && prop_bytes > 0);
119
120 if (prop_bytes || (hwid & ~MPIDR_HWID_BITMASK)) {
121 of_node_put(cpu);
122 return;
123 }
124
125 /*
126 * Duplicate MPIDRs are a recipe for disaster.
127 * Scan all initialized entries and check for
128 * duplicates. If any is found just bail out.
129 * temp values were initialized to UINT_MAX
130 * to avoid matching valid MPIDR[23:0] values.
131 */
132 for (j = 0; j < cpuidx; j++)
133 if (WARN(tmp_map[j] == hwid,
134 "Duplicate /cpu reg properties in the DT\n")) {
135 of_node_put(cpu);
136 return;
137 }
138
139 /*
140 * Build a stashed array of MPIDR values. Numbering scheme
141 * requires that if detected the boot CPU must be assigned
142 * logical id 0. Other CPUs get sequential indexes starting
143 * from 1. If a CPU node with a reg property matching the
144 * boot CPU MPIDR is detected, this is recorded so that the
145 * logical map built from DT is validated and can be used
146 * to override the map created in smp_setup_processor_id().
147 */
148 if (hwid == mpidr) {
149 i = 0;
150 bootcpu_valid = true;
151 } else {
152 i = cpuidx++;
153 }
154
155 if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than "
156 "max cores %u, capping them\n",
157 cpuidx, nr_cpu_ids)) {
158 cpuidx = nr_cpu_ids;
159 of_node_put(cpu);
160 break;
161 }
162
163 tmp_map[i] = hwid;
164
165 if (!found_method)
166 found_method = set_smp_ops_by_method(cpu);
167 }
168
169 /*
170 * Fallback to an enable-method in the cpus node if nothing found in
171 * a cpu node.
172 */
173 if (!found_method)
174 set_smp_ops_by_method(cpus);
175
176 if (!bootcpu_valid) {
177 pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n");
178 return;
179 }
180
181 /*
182 * Since the boot CPU node contains proper data, and all nodes have
183 * a reg property, the DT CPU list can be considered valid and the
184 * logical map created in smp_setup_processor_id() can be overridden
185 */
186 for (i = 0; i < cpuidx; i++) {
187 set_cpu_possible(i, true);
188 cpu_logical_map(i) = tmp_map[i];
189 pr_debug("cpu logical map 0x%x\n", cpu_logical_map(i));
190 }
191 }
192
arch_match_cpu_phys_id(int cpu,u64 phys_id)193 bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
194 {
195 return phys_id == cpu_logical_map(cpu);
196 }
197
arch_get_next_mach(const char * const ** match)198 static const void * __init arch_get_next_mach(const char *const **match)
199 {
200 static const struct machine_desc *mdesc = __arch_info_begin;
201 const struct machine_desc *m = mdesc;
202
203 if (m >= __arch_info_end)
204 return NULL;
205
206 mdesc++;
207 *match = m->dt_compat;
208 return m;
209 }
210
211 /**
212 * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
213 * @dt_phys: physical address of dt blob
214 *
215 * If a dtb was passed to the kernel in r2, then use it to choose the
216 * correct machine_desc and to setup the system.
217 */
setup_machine_fdt(unsigned int dt_phys)218 const struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
219 {
220 const struct machine_desc *mdesc, *mdesc_best = NULL;
221
222 #if defined(CONFIG_ARCH_MULTIPLATFORM) || defined(CONFIG_ARM_SINGLE_ARMV7M)
223 DT_MACHINE_START(GENERIC_DT, "Generic DT based system")
224 .l2c_aux_val = 0x0,
225 .l2c_aux_mask = ~0x0,
226 MACHINE_END
227
228 mdesc_best = &__mach_desc_GENERIC_DT;
229 #endif
230
231 if (!dt_phys || !early_init_dt_verify(phys_to_virt(dt_phys)))
232 return NULL;
233
234 mdesc = of_flat_dt_match_machine(mdesc_best, arch_get_next_mach);
235
236 if (!mdesc) {
237 const char *prop;
238 int size;
239 unsigned long dt_root;
240
241 early_print("\nError: unrecognized/unsupported "
242 "device tree compatible list:\n[ ");
243
244 dt_root = of_get_flat_dt_root();
245 prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
246 while (size > 0) {
247 early_print("'%s' ", prop);
248 size -= strlen(prop) + 1;
249 prop += strlen(prop) + 1;
250 }
251 early_print("]\n\n");
252
253 dump_machine_table(); /* does not return */
254 }
255
256 /* We really don't want to do this, but sometimes firmware provides buggy data */
257 if (mdesc->dt_fixup)
258 mdesc->dt_fixup();
259
260 early_init_dt_scan_nodes();
261
262 /* Change machine number to match the mdesc we're using */
263 __machine_arch_type = mdesc->nr;
264
265 return mdesc;
266 }
267
