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/smp_plat.h>
27 #include <asm/mach/arch.h>
28 #include <asm/mach-types.h>
29
30
31 #ifdef CONFIG_SMP
32 extern struct of_cpu_method __cpu_method_of_table[];
33
34 static const struct of_cpu_method __cpu_method_of_table_sentinel
35 __used __section(__cpu_method_of_table_end);
36
37
set_smp_ops_by_method(struct device_node * node)38 static int __init set_smp_ops_by_method(struct device_node *node)
39 {
40 const char *method;
41 struct of_cpu_method *m = __cpu_method_of_table;
42
43 if (of_property_read_string(node, "enable-method", &method))
44 return 0;
45
46 for (; m->method; m++)
47 if (!strcmp(m->method, method)) {
48 smp_set_ops(m->ops);
49 return 1;
50 }
51
52 return 0;
53 }
54 #else
set_smp_ops_by_method(struct device_node * node)55 static inline int set_smp_ops_by_method(struct device_node *node)
56 {
57 return 1;
58 }
59 #endif
60
61
62 /*
63 * arm_dt_init_cpu_maps - Function retrieves cpu nodes from the device tree
64 * and builds the cpu logical map array containing MPIDR values related to
65 * logical cpus
66 *
67 * Updates the cpu possible mask with the number of parsed cpu nodes
68 */
arm_dt_init_cpu_maps(void)69 void __init arm_dt_init_cpu_maps(void)
70 {
71 /*
72 * Temp logical map is initialized with UINT_MAX values that are
73 * considered invalid logical map entries since the logical map must
74 * contain a list of MPIDR[23:0] values where MPIDR[31:24] must
75 * read as 0.
76 */
77 struct device_node *cpu, *cpus;
78 int found_method = 0;
79 u32 i, j, cpuidx = 1;
80 u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
81
82 u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
83 bool bootcpu_valid = false;
84 cpus = of_find_node_by_path("/cpus");
85
86 if (!cpus)
87 return;
88
89 for_each_child_of_node(cpus, cpu) {
90 u32 hwid;
91
92 if (of_node_cmp(cpu->type, "cpu"))
93 continue;
94
95 pr_debug(" * %s...\n", cpu->full_name);
96 /*
97 * A device tree containing CPU nodes with missing "reg"
98 * properties is considered invalid to build the
99 * cpu_logical_map.
100 */
101 if (of_property_read_u32(cpu, "reg", &hwid)) {
102 pr_debug(" * %s missing reg property\n",
103 cpu->full_name);
104 return;
105 }
106
107 /*
108 * 8 MSBs must be set to 0 in the DT since the reg property
109 * defines the MPIDR[23:0].
110 */
111 if (hwid & ~MPIDR_HWID_BITMASK)
112 return;
113
114 /*
115 * Duplicate MPIDRs are a recipe for disaster.
116 * Scan all initialized entries and check for
117 * duplicates. If any is found just bail out.
118 * temp values were initialized to UINT_MAX
119 * to avoid matching valid MPIDR[23:0] values.
120 */
121 for (j = 0; j < cpuidx; j++)
122 if (WARN(tmp_map[j] == hwid, "Duplicate /cpu reg "
123 "properties in the DT\n"))
124 return;
125
126 /*
127 * Build a stashed array of MPIDR values. Numbering scheme
128 * requires that if detected the boot CPU must be assigned
129 * logical id 0. Other CPUs get sequential indexes starting
130 * from 1. If a CPU node with a reg property matching the
131 * boot CPU MPIDR is detected, this is recorded so that the
132 * logical map built from DT is validated and can be used
133 * to override the map created in smp_setup_processor_id().
134 */
135 if (hwid == mpidr) {
136 i = 0;
137 bootcpu_valid = true;
138 } else {
139 i = cpuidx++;
140 }
141
142 if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than "
143 "max cores %u, capping them\n",
144 cpuidx, nr_cpu_ids)) {
145 cpuidx = nr_cpu_ids;
146 break;
147 }
148
149 tmp_map[i] = hwid;
150
151 if (!found_method)
152 found_method = set_smp_ops_by_method(cpu);
153 }
154
155 /*
156 * Fallback to an enable-method in the cpus node if nothing found in
157 * a cpu node.
158 */
159 if (!found_method)
160 set_smp_ops_by_method(cpus);
161
162 if (!bootcpu_valid) {
163 pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n");
164 return;
165 }
166
167 /*
168 * Since the boot CPU node contains proper data, and all nodes have
169 * a reg property, the DT CPU list can be considered valid and the
170 * logical map created in smp_setup_processor_id() can be overridden
171 */
172 for (i = 0; i < cpuidx; i++) {
173 set_cpu_possible(i, true);
174 cpu_logical_map(i) = tmp_map[i];
175 pr_debug("cpu logical map 0x%x\n", cpu_logical_map(i));
176 }
177 }
178
arch_match_cpu_phys_id(int cpu,u64 phys_id)179 bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
180 {
181 return phys_id == cpu_logical_map(cpu);
182 }
183
arch_get_next_mach(const char * const ** match)184 static const void * __init arch_get_next_mach(const char *const **match)
185 {
186 static const struct machine_desc *mdesc = __arch_info_begin;
187 const struct machine_desc *m = mdesc;
188
189 if (m >= __arch_info_end)
190 return NULL;
191
192 mdesc++;
193 *match = m->dt_compat;
194 return m;
195 }
196
197 /**
198 * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
199 * @dt_phys: physical address of dt blob
200 *
201 * If a dtb was passed to the kernel in r2, then use it to choose the
202 * correct machine_desc and to setup the system.
203 */
setup_machine_fdt(unsigned int dt_phys)204 const struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
205 {
206 const struct machine_desc *mdesc, *mdesc_best = NULL;
207
208 #ifdef CONFIG_ARCH_MULTIPLATFORM
209 DT_MACHINE_START(GENERIC_DT, "Generic DT based system")
210 MACHINE_END
211
212 mdesc_best = &__mach_desc_GENERIC_DT;
213 #endif
214
215 if (!dt_phys || !early_init_dt_verify(phys_to_virt(dt_phys)))
216 return NULL;
217
218 mdesc = of_flat_dt_match_machine(mdesc_best, arch_get_next_mach);
219
220 if (!mdesc) {
221 const char *prop;
222 int size;
223 unsigned long dt_root;
224
225 early_print("\nError: unrecognized/unsupported "
226 "device tree compatible list:\n[ ");
227
228 dt_root = of_get_flat_dt_root();
229 prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
230 while (size > 0) {
231 early_print("'%s' ", prop);
232 size -= strlen(prop) + 1;
233 prop += strlen(prop) + 1;
234 }
235 early_print("]\n\n");
236
237 dump_machine_table(); /* does not return */
238 }
239
240 /* We really don't want to do this, but sometimes firmware provides buggy data */
241 if (mdesc->dt_fixup)
242 mdesc->dt_fixup();
243
244 early_init_dt_scan_nodes();
245
246 /* Change machine number to match the mdesc we're using */
247 __machine_arch_type = mdesc->nr;
248
249 return mdesc;
250 }
251