xref: /openbmc/linux/arch/arm/kernel/devtree.c (revision 84fc8636)
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 		u32 hwid = of_get_cpu_hwid(cpu, 0);
88 
89 		pr_debug(" * %pOF...\n", cpu);
90 
91 		/*
92 		 * Bits n:24 must be set to 0 in the DT since the reg property
93 		 * defines the MPIDR[23:0].
94 		 */
95 		if (hwid & ~MPIDR_HWID_BITMASK) {
96 			of_node_put(cpu);
97 			return;
98 		}
99 
100 		/*
101 		 * Duplicate MPIDRs are a recipe for disaster.
102 		 * Scan all initialized entries and check for
103 		 * duplicates. If any is found just bail out.
104 		 * temp values were initialized to UINT_MAX
105 		 * to avoid matching valid MPIDR[23:0] values.
106 		 */
107 		for (j = 0; j < cpuidx; j++)
108 			if (WARN(tmp_map[j] == hwid,
109 				 "Duplicate /cpu reg properties in the DT\n")) {
110 				of_node_put(cpu);
111 				return;
112 			}
113 
114 		/*
115 		 * Build a stashed array of MPIDR values. Numbering scheme
116 		 * requires that if detected the boot CPU must be assigned
117 		 * logical id 0. Other CPUs get sequential indexes starting
118 		 * from 1. If a CPU node with a reg property matching the
119 		 * boot CPU MPIDR is detected, this is recorded so that the
120 		 * logical map built from DT is validated and can be used
121 		 * to override the map created in smp_setup_processor_id().
122 		 */
123 		if (hwid == mpidr) {
124 			i = 0;
125 			bootcpu_valid = true;
126 		} else {
127 			i = cpuidx++;
128 		}
129 
130 		if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than "
131 					       "max cores %u, capping them\n",
132 					       cpuidx, nr_cpu_ids)) {
133 			cpuidx = nr_cpu_ids;
134 			of_node_put(cpu);
135 			break;
136 		}
137 
138 		tmp_map[i] = hwid;
139 
140 		if (!found_method)
141 			found_method = set_smp_ops_by_method(cpu);
142 	}
143 
144 	/*
145 	 * Fallback to an enable-method in the cpus node if nothing found in
146 	 * a cpu node.
147 	 */
148 	if (!found_method)
149 		set_smp_ops_by_method(cpus);
150 
151 	if (!bootcpu_valid) {
152 		pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n");
153 		return;
154 	}
155 
156 	/*
157 	 * Since the boot CPU node contains proper data, and all nodes have
158 	 * a reg property, the DT CPU list can be considered valid and the
159 	 * logical map created in smp_setup_processor_id() can be overridden
160 	 */
161 	for (i = 0; i < cpuidx; i++) {
162 		set_cpu_possible(i, true);
163 		cpu_logical_map(i) = tmp_map[i];
164 		pr_debug("cpu logical map 0x%x\n", cpu_logical_map(i));
165 	}
166 }
167 
arch_match_cpu_phys_id(int cpu,u64 phys_id)168 bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
169 {
170 	return phys_id == cpu_logical_map(cpu);
171 }
172 
arch_get_next_mach(const char * const ** match)173 static const void * __init arch_get_next_mach(const char *const **match)
174 {
175 	static const struct machine_desc *mdesc = __arch_info_begin;
176 	const struct machine_desc *m = mdesc;
177 
178 	if (m >= __arch_info_end)
179 		return NULL;
180 
181 	mdesc++;
182 	*match = m->dt_compat;
183 	return m;
184 }
185 
186 /**
187  * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
188  * @dt_virt: virtual address of dt blob
189  *
190  * If a dtb was passed to the kernel in r2, then use it to choose the
191  * correct machine_desc and to setup the system.
192  */
setup_machine_fdt(void * dt_virt)193 const struct machine_desc * __init setup_machine_fdt(void *dt_virt)
194 {
195 	const struct machine_desc *mdesc, *mdesc_best = NULL;
196 
197 	DT_MACHINE_START(GENERIC_DT, "Generic DT based system")
198 		.l2c_aux_val = 0x0,
199 		.l2c_aux_mask = ~0x0,
200 	MACHINE_END
201 
202 	mdesc_best = &__mach_desc_GENERIC_DT;
203 
204 	if (!dt_virt || !early_init_dt_verify(dt_virt))
205 		return NULL;
206 
207 	mdesc = of_flat_dt_match_machine(mdesc_best, arch_get_next_mach);
208 
209 	if (!mdesc) {
210 		const char *prop;
211 		int size;
212 		unsigned long dt_root;
213 
214 		early_print("\nError: unrecognized/unsupported "
215 			    "device tree compatible list:\n[ ");
216 
217 		dt_root = of_get_flat_dt_root();
218 		prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
219 		while (size > 0) {
220 			early_print("'%s' ", prop);
221 			size -= strlen(prop) + 1;
222 			prop += strlen(prop) + 1;
223 		}
224 		early_print("]\n\n");
225 
226 		dump_machine_table(); /* does not return */
227 	}
228 
229 	/* We really don't want to do this, but sometimes firmware provides buggy data */
230 	if (mdesc->dt_fixup)
231 		mdesc->dt_fixup();
232 
233 	early_init_dt_scan_nodes();
234 
235 	/* Change machine number to match the mdesc we're using */
236 	__machine_arch_type = mdesc->nr;
237 
238 	return mdesc;
239 }
240