xref: /openbmc/linux/arch/arm/kernel/devtree.c (revision 7b6d864b)
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 
22 #include <asm/cputype.h>
23 #include <asm/setup.h>
24 #include <asm/page.h>
25 #include <asm/smp_plat.h>
26 #include <asm/mach/arch.h>
27 #include <asm/mach-types.h>
28 
29 void __init early_init_dt_add_memory_arch(u64 base, u64 size)
30 {
31 	arm_add_memory(base, size);
32 }
33 
34 void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
35 {
36 	return alloc_bootmem_align(size, align);
37 }
38 
39 void __init arm_dt_memblock_reserve(void)
40 {
41 	u64 *reserve_map, base, size;
42 
43 	if (!initial_boot_params)
44 		return;
45 
46 	/* Reserve the dtb region */
47 	memblock_reserve(virt_to_phys(initial_boot_params),
48 			 be32_to_cpu(initial_boot_params->totalsize));
49 
50 	/*
51 	 * Process the reserve map.  This will probably overlap the initrd
52 	 * and dtb locations which are already reserved, but overlaping
53 	 * doesn't hurt anything
54 	 */
55 	reserve_map = ((void*)initial_boot_params) +
56 			be32_to_cpu(initial_boot_params->off_mem_rsvmap);
57 	while (1) {
58 		base = be64_to_cpup(reserve_map++);
59 		size = be64_to_cpup(reserve_map++);
60 		if (!size)
61 			break;
62 		memblock_reserve(base, size);
63 	}
64 }
65 
66 /*
67  * arm_dt_init_cpu_maps - Function retrieves cpu nodes from the device tree
68  * and builds the cpu logical map array containing MPIDR values related to
69  * logical cpus
70  *
71  * Updates the cpu possible mask with the number of parsed cpu nodes
72  */
73 void __init arm_dt_init_cpu_maps(void)
74 {
75 	/*
76 	 * Temp logical map is initialized with UINT_MAX values that are
77 	 * considered invalid logical map entries since the logical map must
78 	 * contain a list of MPIDR[23:0] values where MPIDR[31:24] must
79 	 * read as 0.
80 	 */
81 	struct device_node *cpu, *cpus;
82 	u32 i, j, cpuidx = 1;
83 	u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
84 
85 	u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
86 	bool bootcpu_valid = false;
87 	cpus = of_find_node_by_path("/cpus");
88 
89 	if (!cpus)
90 		return;
91 
92 	for_each_child_of_node(cpus, cpu) {
93 		u32 hwid;
94 
95 		if (of_node_cmp(cpu->type, "cpu"))
96 			continue;
97 
98 		pr_debug(" * %s...\n", cpu->full_name);
99 		/*
100 		 * A device tree containing CPU nodes with missing "reg"
101 		 * properties is considered invalid to build the
102 		 * cpu_logical_map.
103 		 */
104 		if (of_property_read_u32(cpu, "reg", &hwid)) {
105 			pr_debug(" * %s missing reg property\n",
106 				     cpu->full_name);
107 			return;
108 		}
109 
110 		/*
111 		 * 8 MSBs must be set to 0 in the DT since the reg property
112 		 * defines the MPIDR[23:0].
113 		 */
114 		if (hwid & ~MPIDR_HWID_BITMASK)
115 			return;
116 
117 		/*
118 		 * Duplicate MPIDRs are a recipe for disaster.
119 		 * Scan all initialized entries and check for
120 		 * duplicates. If any is found just bail out.
121 		 * temp values were initialized to UINT_MAX
122 		 * to avoid matching valid MPIDR[23:0] values.
123 		 */
124 		for (j = 0; j < cpuidx; j++)
125 			if (WARN(tmp_map[j] == hwid, "Duplicate /cpu reg "
126 						     "properties in the DT\n"))
127 				return;
128 
129 		/*
130 		 * Build a stashed array of MPIDR values. Numbering scheme
131 		 * requires that if detected the boot CPU must be assigned
132 		 * logical id 0. Other CPUs get sequential indexes starting
133 		 * from 1. If a CPU node with a reg property matching the
134 		 * boot CPU MPIDR is detected, this is recorded so that the
135 		 * logical map built from DT is validated and can be used
136 		 * to override the map created in smp_setup_processor_id().
137 		 */
138 		if (hwid == mpidr) {
139 			i = 0;
140 			bootcpu_valid = true;
141 		} else {
142 			i = cpuidx++;
143 		}
144 
145 		if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than "
146 					       "max cores %u, capping them\n",
147 					       cpuidx, nr_cpu_ids)) {
148 			cpuidx = nr_cpu_ids;
149 			break;
150 		}
151 
152 		tmp_map[i] = hwid;
153 	}
154 
155 	if (!bootcpu_valid) {
156 		pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n");
157 		return;
158 	}
159 
160 	/*
161 	 * Since the boot CPU node contains proper data, and all nodes have
162 	 * a reg property, the DT CPU list can be considered valid and the
163 	 * logical map created in smp_setup_processor_id() can be overridden
164 	 */
165 	for (i = 0; i < cpuidx; i++) {
166 		set_cpu_possible(i, true);
167 		cpu_logical_map(i) = tmp_map[i];
168 		pr_debug("cpu logical map 0x%x\n", cpu_logical_map(i));
169 	}
170 }
171 
172 /**
173  * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
174  * @dt_phys: physical address of dt blob
175  *
176  * If a dtb was passed to the kernel in r2, then use it to choose the
177  * correct machine_desc and to setup the system.
178  */
179 struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
180 {
181 	struct boot_param_header *devtree;
182 	struct machine_desc *mdesc, *mdesc_best = NULL;
183 	unsigned int score, mdesc_score = ~1;
184 	unsigned long dt_root;
185 	const char *model;
186 
187 #ifdef CONFIG_ARCH_MULTIPLATFORM
188 	DT_MACHINE_START(GENERIC_DT, "Generic DT based system")
189 	MACHINE_END
190 
191 	mdesc_best = (struct machine_desc *)&__mach_desc_GENERIC_DT;
192 #endif
193 
194 	if (!dt_phys)
195 		return NULL;
196 
197 	devtree = phys_to_virt(dt_phys);
198 
199 	/* check device tree validity */
200 	if (be32_to_cpu(devtree->magic) != OF_DT_HEADER)
201 		return NULL;
202 
203 	/* Search the mdescs for the 'best' compatible value match */
204 	initial_boot_params = devtree;
205 	dt_root = of_get_flat_dt_root();
206 	for_each_machine_desc(mdesc) {
207 		score = of_flat_dt_match(dt_root, mdesc->dt_compat);
208 		if (score > 0 && score < mdesc_score) {
209 			mdesc_best = mdesc;
210 			mdesc_score = score;
211 		}
212 	}
213 	if (!mdesc_best) {
214 		const char *prop;
215 		long size;
216 
217 		early_print("\nError: unrecognized/unsupported "
218 			    "device tree compatible list:\n[ ");
219 
220 		prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
221 		while (size > 0) {
222 			early_print("'%s' ", prop);
223 			size -= strlen(prop) + 1;
224 			prop += strlen(prop) + 1;
225 		}
226 		early_print("]\n\n");
227 
228 		dump_machine_table(); /* does not return */
229 	}
230 
231 	model = of_get_flat_dt_prop(dt_root, "model", NULL);
232 	if (!model)
233 		model = of_get_flat_dt_prop(dt_root, "compatible", NULL);
234 	if (!model)
235 		model = "<unknown>";
236 	pr_info("Machine: %s, model: %s\n", mdesc_best->name, model);
237 
238 	/* Retrieve various information from the /chosen node */
239 	of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line);
240 	/* Initialize {size,address}-cells info */
241 	of_scan_flat_dt(early_init_dt_scan_root, NULL);
242 	/* Setup memory, calling early_init_dt_add_memory_arch */
243 	of_scan_flat_dt(early_init_dt_scan_memory, NULL);
244 
245 	/* Change machine number to match the mdesc we're using */
246 	__machine_arch_type = mdesc_best->nr;
247 
248 	return mdesc_best;
249 }
250