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
32extern struct of_cpu_method __cpu_method_of_table[];
33
34static const struct of_cpu_method __cpu_method_of_table_sentinel
35	__used __section(__cpu_method_of_table_end);
36
37
38static 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
55static 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 */
69void __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
179bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
180{
181	return phys_id == cpu_logical_map(cpu);
182}
183
184static 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 */
204const 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