1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/arch/arm/kernel/devtree.c
4 *
5 * Copyright (C) 2009 Canonical Ltd. <jeremy.kerr@canonical.com>
6 */
7
8 #include <linux/init.h>
9 #include <linux/export.h>
10 #include <linux/errno.h>
11 #include <linux/types.h>
12 #include <linux/memblock.h>
13 #include <linux/of.h>
14 #include <linux/of_fdt.h>
15 #include <linux/of_irq.h>
16 #include <linux/of_platform.h>
17 #include <linux/smp.h>
18
19 #include <asm/cputype.h>
20 #include <asm/setup.h>
21 #include <asm/page.h>
22 #include <asm/prom.h>
23 #include <asm/smp_plat.h>
24 #include <asm/mach/arch.h>
25 #include <asm/mach-types.h>
26
27
28 #ifdef CONFIG_SMP
29 extern struct of_cpu_method __cpu_method_of_table[];
30
31 static const struct of_cpu_method __cpu_method_of_table_sentinel
32 __used __section(__cpu_method_of_table_end);
33
34
set_smp_ops_by_method(struct device_node * node)35 static int __init set_smp_ops_by_method(struct device_node *node)
36 {
37 const char *method;
38 struct of_cpu_method *m = __cpu_method_of_table;
39
40 if (of_property_read_string(node, "enable-method", &method))
41 return 0;
42
43 for (; m->method; m++)
44 if (!strcmp(m->method, method)) {
45 smp_set_ops(m->ops);
46 return 1;
47 }
48
49 return 0;
50 }
51 #else
set_smp_ops_by_method(struct device_node * node)52 static inline int set_smp_ops_by_method(struct device_node *node)
53 {
54 return 1;
55 }
56 #endif
57
58
59 /*
60 * arm_dt_init_cpu_maps - Function retrieves cpu nodes from the device tree
61 * and builds the cpu logical map array containing MPIDR values related to
62 * logical cpus
63 *
64 * Updates the cpu possible mask with the number of parsed cpu nodes
65 */
arm_dt_init_cpu_maps(void)66 void __init arm_dt_init_cpu_maps(void)
67 {
68 /*
69 * Temp logical map is initialized with UINT_MAX values that are
70 * considered invalid logical map entries since the logical map must
71 * contain a list of MPIDR[23:0] values where MPIDR[31:24] must
72 * read as 0.
73 */
74 struct device_node *cpu, *cpus;
75 int found_method = 0;
76 u32 i, j, cpuidx = 1;
77 u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
78
79 u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
80 bool bootcpu_valid = false;
81 cpus = of_find_node_by_path("/cpus");
82
83 if (!cpus)
84 return;
85
86 for_each_of_cpu_node(cpu) {
87 const __be32 *cell;
88 int prop_bytes;
89 u32 hwid;
90
91 pr_debug(" * %pOF...\n", cpu);
92 /*
93 * A device tree containing CPU nodes with missing "reg"
94 * properties is considered invalid to build the
95 * cpu_logical_map.
96 */
97 cell = of_get_property(cpu, "reg", &prop_bytes);
98 if (!cell || prop_bytes < sizeof(*cell)) {
99 pr_debug(" * %pOF missing reg property\n", cpu);
100 of_node_put(cpu);
101 return;
102 }
103
104 /*
105 * Bits n:24 must be set to 0 in the DT since the reg property
106 * defines the MPIDR[23:0].
107 */
108 do {
109 hwid = be32_to_cpu(*cell++);
110 prop_bytes -= sizeof(*cell);
111 } while (!hwid && prop_bytes > 0);
112
113 if (prop_bytes || (hwid & ~MPIDR_HWID_BITMASK)) {
114 of_node_put(cpu);
115 return;
116 }
117
118 /*
119 * Duplicate MPIDRs are a recipe for disaster.
120 * Scan all initialized entries and check for
121 * duplicates. If any is found just bail out.
122 * temp values were initialized to UINT_MAX
123 * to avoid matching valid MPIDR[23:0] values.
124 */
125 for (j = 0; j < cpuidx; j++)
126 if (WARN(tmp_map[j] == hwid,
127 "Duplicate /cpu reg properties in the DT\n")) {
128 of_node_put(cpu);
129 return;
130 }
131
132 /*
133 * Build a stashed array of MPIDR values. Numbering scheme
134 * requires that if detected the boot CPU must be assigned
135 * logical id 0. Other CPUs get sequential indexes starting
136 * from 1. If a CPU node with a reg property matching the
137 * boot CPU MPIDR is detected, this is recorded so that the
138 * logical map built from DT is validated and can be used
139 * to override the map created in smp_setup_processor_id().
140 */
141 if (hwid == mpidr) {
142 i = 0;
143 bootcpu_valid = true;
144 } else {
145 i = cpuidx++;
146 }
147
148 if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than "
149 "max cores %u, capping them\n",
150 cpuidx, nr_cpu_ids)) {
151 cpuidx = nr_cpu_ids;
152 of_node_put(cpu);
153 break;
154 }
155
156 tmp_map[i] = hwid;
157
158 if (!found_method)
159 found_method = set_smp_ops_by_method(cpu);
160 }
161
162 /*
163 * Fallback to an enable-method in the cpus node if nothing found in
164 * a cpu node.
165 */
166 if (!found_method)
167 set_smp_ops_by_method(cpus);
168
169 if (!bootcpu_valid) {
170 pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n");
171 return;
172 }
173
174 /*
175 * Since the boot CPU node contains proper data, and all nodes have
176 * a reg property, the DT CPU list can be considered valid and the
177 * logical map created in smp_setup_processor_id() can be overridden
178 */
179 for (i = 0; i < cpuidx; i++) {
180 set_cpu_possible(i, true);
181 cpu_logical_map(i) = tmp_map[i];
182 pr_debug("cpu logical map 0x%x\n", cpu_logical_map(i));
183 }
184 }
185
arch_match_cpu_phys_id(int cpu,u64 phys_id)186 bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
187 {
188 return phys_id == cpu_logical_map(cpu);
189 }
190
arch_get_next_mach(const char * const ** match)191 static const void * __init arch_get_next_mach(const char *const **match)
192 {
193 static const struct machine_desc *mdesc = __arch_info_begin;
194 const struct machine_desc *m = mdesc;
195
196 if (m >= __arch_info_end)
197 return NULL;
198
199 mdesc++;
200 *match = m->dt_compat;
201 return m;
202 }
203
204 /**
205 * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
206 * @dt_virt: virtual address of dt blob
207 *
208 * If a dtb was passed to the kernel in r2, then use it to choose the
209 * correct machine_desc and to setup the system.
210 */
setup_machine_fdt(void * dt_virt)211 const struct machine_desc * __init setup_machine_fdt(void *dt_virt)
212 {
213 const struct machine_desc *mdesc, *mdesc_best = NULL;
214
215 #if defined(CONFIG_ARCH_MULTIPLATFORM) || defined(CONFIG_ARM_SINGLE_ARMV7M)
216 DT_MACHINE_START(GENERIC_DT, "Generic DT based system")
217 .l2c_aux_val = 0x0,
218 .l2c_aux_mask = ~0x0,
219 MACHINE_END
220
221 mdesc_best = &__mach_desc_GENERIC_DT;
222 #endif
223
224 if (!dt_virt || !early_init_dt_verify(dt_virt))
225 return NULL;
226
227 mdesc = of_flat_dt_match_machine(mdesc_best, arch_get_next_mach);
228
229 if (!mdesc) {
230 const char *prop;
231 int size;
232 unsigned long dt_root;
233
234 early_print("\nError: unrecognized/unsupported "
235 "device tree compatible list:\n[ ");
236
237 dt_root = of_get_flat_dt_root();
238 prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
239 while (size > 0) {
240 early_print("'%s' ", prop);
241 size -= strlen(prop) + 1;
242 prop += strlen(prop) + 1;
243 }
244 early_print("]\n\n");
245
246 dump_machine_table(); /* does not return */
247 }
248
249 /* We really don't want to do this, but sometimes firmware provides buggy data */
250 if (mdesc->dt_fixup)
251 mdesc->dt_fixup();
252
253 early_init_dt_scan_nodes();
254
255 /* Change machine number to match the mdesc we're using */
256 __machine_arch_type = mdesc->nr;
257
258 return mdesc;
259 }
260