2 * linux/arch/arm/kernel/devtree.c
4 * Copyright (C) 2009 Canonical Ltd. <jeremy.kerr@canonical.com>
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.
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>
18 #include <linux/of_fdt.h>
19 #include <linux/of_irq.h>
20 #include <linux/of_platform.h>
21 #include <linux/smp.h>
23 #include <asm/cputype.h>
24 #include <asm/setup.h>
26 #include <asm/smp_plat.h>
27 #include <asm/mach/arch.h>
28 #include <asm/mach-types.h>
32 extern struct of_cpu_method __cpu_method_of_table[];
34 static const struct of_cpu_method __cpu_method_of_table_sentinel
35 __used __section(__cpu_method_of_table_end);
38 static int __init set_smp_ops_by_method(struct device_node *node)
41 struct of_cpu_method *m = __cpu_method_of_table;
43 if (of_property_read_string(node, "enable-method", &method))
46 for (; m->method; m++)
47 if (!strcmp(m->method, method)) {
55 static inline int set_smp_ops_by_method(struct device_node *node)
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
67 * Updates the cpu possible mask with the number of parsed cpu nodes
69 void __init arm_dt_init_cpu_maps(void)
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
77 struct device_node *cpu, *cpus;
80 u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
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");
89 for_each_child_of_node(cpus, cpu) {
94 if (of_node_cmp(cpu->type, "cpu"))
97 pr_debug(" * %s...\n", cpu->full_name);
99 * A device tree containing CPU nodes with missing "reg"
100 * properties is considered invalid to build the
103 cell = of_get_property(cpu, "reg", &prop_bytes);
104 if (!cell || prop_bytes < sizeof(*cell)) {
105 pr_debug(" * %s missing reg property\n",
112 * Bits n:24 must be set to 0 in the DT since the reg property
113 * defines the MPIDR[23:0].
116 hwid = be32_to_cpu(*cell++);
117 prop_bytes -= sizeof(*cell);
118 } while (!hwid && prop_bytes > 0);
120 if (prop_bytes || (hwid & ~MPIDR_HWID_BITMASK)) {
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.
132 for (j = 0; j < cpuidx; j++)
133 if (WARN(tmp_map[j] == hwid,
134 "Duplicate /cpu reg properties in the DT\n")) {
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().
150 bootcpu_valid = true;
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)) {
166 found_method = set_smp_ops_by_method(cpu);
170 * Fallback to an enable-method in the cpus node if nothing found in
174 set_smp_ops_by_method(cpus);
176 if (!bootcpu_valid) {
177 pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n");
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
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));
193 bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
195 return phys_id == cpu_logical_map(cpu);
198 static const void * __init arch_get_next_mach(const char *const **match)
200 static const struct machine_desc *mdesc = __arch_info_begin;
201 const struct machine_desc *m = mdesc;
203 if (m >= __arch_info_end)
207 *match = m->dt_compat;
212 * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
213 * @dt_phys: physical address of dt blob
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.
218 const struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
220 const struct machine_desc *mdesc, *mdesc_best = NULL;
222 #ifdef CONFIG_ARCH_MULTIPLATFORM
223 DT_MACHINE_START(GENERIC_DT, "Generic DT based system")
226 mdesc_best = &__mach_desc_GENERIC_DT;
229 if (!dt_phys || !early_init_dt_verify(phys_to_virt(dt_phys)))
232 mdesc = of_flat_dt_match_machine(mdesc_best, arch_get_next_mach);
237 unsigned long dt_root;
239 early_print("\nError: unrecognized/unsupported "
240 "device tree compatible list:\n[ ");
242 dt_root = of_get_flat_dt_root();
243 prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
245 early_print("'%s' ", prop);
246 size -= strlen(prop) + 1;
247 prop += strlen(prop) + 1;
249 early_print("]\n\n");
251 dump_machine_table(); /* does not return */
254 /* We really don't want to do this, but sometimes firmware provides buggy data */
258 early_init_dt_scan_nodes();
260 /* Change machine number to match the mdesc we're using */
261 __machine_arch_type = mdesc->nr;