xref: /openbmc/linux/arch/arm64/kernel/acpi.c (revision fccb9a81fd08b61bed91ddef88341694f8ecbfd1)
1 /*
2  *  ARM64 Specific Low-Level ACPI Boot Support
3  *
4  *  Copyright (C) 2013-2014, Linaro Ltd.
5  *	Author: Al Stone <al.stone@linaro.org>
6  *	Author: Graeme Gregory <graeme.gregory@linaro.org>
7  *	Author: Hanjun Guo <hanjun.guo@linaro.org>
8  *	Author: Tomasz Nowicki <tomasz.nowicki@linaro.org>
9  *	Author: Naresh Bhat <naresh.bhat@linaro.org>
10  *
11  *  This program is free software; you can redistribute it and/or modify
12  *  it under the terms of the GNU General Public License version 2 as
13  *  published by the Free Software Foundation.
14  */
15 
16 #define pr_fmt(fmt) "ACPI: " fmt
17 
18 #include <linux/acpi.h>
19 #include <linux/bootmem.h>
20 #include <linux/cpumask.h>
21 #include <linux/init.h>
22 #include <linux/irq.h>
23 #include <linux/irqdomain.h>
24 #include <linux/memblock.h>
25 #include <linux/of_fdt.h>
26 #include <linux/smp.h>
27 
28 #include <asm/cputype.h>
29 #include <asm/cpu_ops.h>
30 #include <asm/smp_plat.h>
31 
32 int acpi_noirq = 1;		/* skip ACPI IRQ initialization */
33 int acpi_disabled = 1;
34 EXPORT_SYMBOL(acpi_disabled);
35 
36 int acpi_pci_disabled = 1;	/* skip ACPI PCI scan and IRQ initialization */
37 EXPORT_SYMBOL(acpi_pci_disabled);
38 
39 /* Processors with enabled flag and sane MPIDR */
40 static int enabled_cpus;
41 
42 /* Boot CPU is valid or not in MADT */
43 static bool bootcpu_valid  __initdata;
44 
45 static bool param_acpi_off __initdata;
46 static bool param_acpi_force __initdata;
47 
48 static int __init parse_acpi(char *arg)
49 {
50 	if (!arg)
51 		return -EINVAL;
52 
53 	/* "acpi=off" disables both ACPI table parsing and interpreter */
54 	if (strcmp(arg, "off") == 0)
55 		param_acpi_off = true;
56 	else if (strcmp(arg, "force") == 0) /* force ACPI to be enabled */
57 		param_acpi_force = true;
58 	else
59 		return -EINVAL;	/* Core will print when we return error */
60 
61 	return 0;
62 }
63 early_param("acpi", parse_acpi);
64 
65 static int __init dt_scan_depth1_nodes(unsigned long node,
66 				       const char *uname, int depth,
67 				       void *data)
68 {
69 	/*
70 	 * Return 1 as soon as we encounter a node at depth 1 that is
71 	 * not the /chosen node.
72 	 */
73 	if (depth == 1 && (strcmp(uname, "chosen") != 0))
74 		return 1;
75 	return 0;
76 }
77 
78 /*
79  * __acpi_map_table() will be called before page_init(), so early_ioremap()
80  * or early_memremap() should be called here to for ACPI table mapping.
81  */
82 char *__init __acpi_map_table(unsigned long phys, unsigned long size)
83 {
84 	if (!size)
85 		return NULL;
86 
87 	return early_memremap(phys, size);
88 }
89 
90 void __init __acpi_unmap_table(char *map, unsigned long size)
91 {
92 	if (!map || !size)
93 		return;
94 
95 	early_memunmap(map, size);
96 }
97 
98 /**
99  * acpi_map_gic_cpu_interface - generates a logical cpu number
100  * and map to MPIDR represented by GICC structure
101  * @mpidr: CPU's hardware id to register, MPIDR represented in MADT
102  * @enabled: this cpu is enabled or not
103  *
104  * Returns the logical cpu number which maps to MPIDR
105  */
106 static int __init acpi_map_gic_cpu_interface(u64 mpidr, u8 enabled)
107 {
108 	int i;
109 
110 	if (mpidr == INVALID_HWID) {
111 		pr_info("Skip MADT cpu entry with invalid MPIDR\n");
112 		return -EINVAL;
113 	}
114 
115 	total_cpus++;
116 	if (!enabled)
117 		return -EINVAL;
118 
119 	if (enabled_cpus >=  NR_CPUS) {
120 		pr_warn("NR_CPUS limit of %d reached, Processor %d/0x%llx ignored.\n",
121 			NR_CPUS, total_cpus, mpidr);
122 		return -EINVAL;
123 	}
124 
125 	/* Check if GICC structure of boot CPU is available in the MADT */
126 	if (cpu_logical_map(0) == mpidr) {
127 		if (bootcpu_valid) {
128 			pr_err("Firmware bug, duplicate CPU MPIDR: 0x%llx in MADT\n",
129 			       mpidr);
130 			return -EINVAL;
131 		}
132 
133 		bootcpu_valid = true;
134 	}
135 
136 	/*
137 	 * Duplicate MPIDRs are a recipe for disaster. Scan
138 	 * all initialized entries and check for
139 	 * duplicates. If any is found just ignore the CPU.
140 	 */
141 	for (i = 1; i < enabled_cpus; i++) {
142 		if (cpu_logical_map(i) == mpidr) {
143 			pr_err("Firmware bug, duplicate CPU MPIDR: 0x%llx in MADT\n",
144 			       mpidr);
145 			return -EINVAL;
146 		}
147 	}
148 
149 	if (!acpi_psci_present())
150 		return -EOPNOTSUPP;
151 
152 	cpu_ops[enabled_cpus] = cpu_get_ops("psci");
153 	/* CPU 0 was already initialized */
154 	if (enabled_cpus) {
155 		if (!cpu_ops[enabled_cpus])
156 			return -EINVAL;
157 
158 		if (cpu_ops[enabled_cpus]->cpu_init(NULL, enabled_cpus))
159 			return -EOPNOTSUPP;
160 
161 		/* map the logical cpu id to cpu MPIDR */
162 		cpu_logical_map(enabled_cpus) = mpidr;
163 	}
164 
165 	enabled_cpus++;
166 	return enabled_cpus;
167 }
168 
169 static int __init
170 acpi_parse_gic_cpu_interface(struct acpi_subtable_header *header,
171 				const unsigned long end)
172 {
173 	struct acpi_madt_generic_interrupt *processor;
174 
175 	processor = (struct acpi_madt_generic_interrupt *)header;
176 
177 	if (BAD_MADT_ENTRY(processor, end))
178 		return -EINVAL;
179 
180 	acpi_table_print_madt_entry(header);
181 
182 	acpi_map_gic_cpu_interface(processor->arm_mpidr & MPIDR_HWID_BITMASK,
183 		processor->flags & ACPI_MADT_ENABLED);
184 
185 	return 0;
186 }
187 
188 /* Parse GIC cpu interface entries in MADT for SMP init */
189 void __init acpi_init_cpus(void)
190 {
191 	int count, i;
192 
193 	/*
194 	 * do a partial walk of MADT to determine how many CPUs
195 	 * we have including disabled CPUs, and get information
196 	 * we need for SMP init
197 	 */
198 	count = acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT,
199 			acpi_parse_gic_cpu_interface, 0);
200 
201 	if (!count) {
202 		pr_err("No GIC CPU interface entries present\n");
203 		return;
204 	} else if (count < 0) {
205 		pr_err("Error parsing GIC CPU interface entry\n");
206 		return;
207 	}
208 
209 	if (!bootcpu_valid) {
210 		pr_err("MADT missing boot CPU MPIDR, not enabling secondaries\n");
211 		return;
212 	}
213 
214 	for (i = 0; i < enabled_cpus; i++)
215 		set_cpu_possible(i, true);
216 
217 	/* Make boot-up look pretty */
218 	pr_info("%d CPUs enabled, %d CPUs total\n", enabled_cpus, total_cpus);
219 }
220 
221 static int __init acpi_parse_fadt(struct acpi_table_header *table)
222 {
223 	struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table;
224 
225 	/*
226 	 * Revision in table header is the FADT Major revision, and there
227 	 * is a minor revision of FADT which was introduced by ACPI 5.1,
228 	 * we only deal with ACPI 5.1 or newer revision to get GIC and SMP
229 	 * boot protocol configuration data, or we will disable ACPI.
230 	 */
231 	if (table->revision > 5 ||
232 	    (table->revision == 5 && fadt->minor_revision >= 1)) {
233 		/*
234 		 * ACPI 5.1 only has two explicit methods to boot up SMP,
235 		 * PSCI and Parking protocol, but the Parking protocol is
236 		 * only specified for ARMv7 now, so make PSCI as the only
237 		 * way for the SMP boot protocol before some updates for
238 		 * the Parking protocol spec.
239 		 */
240 		if (acpi_psci_present())
241 			return 0;
242 
243 		pr_warn("No PSCI support, will not bring up secondary CPUs\n");
244 		return -EOPNOTSUPP;
245 	}
246 
247 	pr_warn("Unsupported FADT revision %d.%d, should be 5.1+, will disable ACPI\n",
248 		table->revision, fadt->minor_revision);
249 	disable_acpi();
250 
251 	return -EINVAL;
252 }
253 
254 /*
255  * acpi_boot_table_init() called from setup_arch(), always.
256  *	1. find RSDP and get its address, and then find XSDT
257  *	2. extract all tables and checksums them all
258  *	3. check ACPI FADT revision
259  *
260  * We can parse ACPI boot-time tables such as MADT after
261  * this function is called.
262  */
263 void __init acpi_boot_table_init(void)
264 {
265 	/*
266 	 * Enable ACPI instead of device tree unless
267 	 * - ACPI has been disabled explicitly (acpi=off), or
268 	 * - the device tree is not empty (it has more than just a /chosen node)
269 	 *   and ACPI has not been force enabled (acpi=force)
270 	 */
271 	if (param_acpi_off ||
272 	    (!param_acpi_force && of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
273 		return;
274 
275 	enable_acpi();
276 
277 	/* Initialize the ACPI boot-time table parser. */
278 	if (acpi_table_init()) {
279 		disable_acpi();
280 		return;
281 	}
282 
283 	if (acpi_table_parse(ACPI_SIG_FADT, acpi_parse_fadt)) {
284 		/* disable ACPI if no FADT is found */
285 		disable_acpi();
286 		pr_err("Can't find FADT\n");
287 	}
288 }
289