1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * RISC-V Specific Low-Level ACPI Boot Support
4 *
5 * Copyright (C) 2013-2014, Linaro Ltd.
6 * Author: Al Stone <al.stone@linaro.org>
7 * Author: Graeme Gregory <graeme.gregory@linaro.org>
8 * Author: Hanjun Guo <hanjun.guo@linaro.org>
9 * Author: Tomasz Nowicki <tomasz.nowicki@linaro.org>
10 * Author: Naresh Bhat <naresh.bhat@linaro.org>
11 *
12 * Copyright (C) 2021-2023, Ventana Micro Systems Inc.
13 * Author: Sunil V L <sunilvl@ventanamicro.com>
14 */
15
16 #include <linux/acpi.h>
17 #include <linux/efi.h>
18 #include <linux/io.h>
19 #include <linux/memblock.h>
20 #include <linux/of_fdt.h>
21 #include <linux/pci.h>
22 #include <linux/serial_core.h>
23
24 int acpi_noirq = 1; /* skip ACPI IRQ initialization */
25 int acpi_disabled = 1;
26 EXPORT_SYMBOL(acpi_disabled);
27
28 int acpi_pci_disabled = 1; /* skip ACPI PCI scan and IRQ initialization */
29 EXPORT_SYMBOL(acpi_pci_disabled);
30
31 static bool param_acpi_off __initdata;
32 static bool param_acpi_on __initdata;
33 static bool param_acpi_force __initdata;
34
35 static struct acpi_madt_rintc cpu_madt_rintc[NR_CPUS];
36
37 static int __init parse_acpi(char *arg)
38 {
39 if (!arg)
40 return -EINVAL;
41
42 /* "acpi=off" disables both ACPI table parsing and interpreter */
43 if (strcmp(arg, "off") == 0)
44 param_acpi_off = true;
45 else if (strcmp(arg, "on") == 0) /* prefer ACPI over DT */
46 param_acpi_on = true;
47 else if (strcmp(arg, "force") == 0) /* force ACPI to be enabled */
48 param_acpi_force = true;
49 else
50 return -EINVAL; /* Core will print when we return error */
51
52 return 0;
53 }
54 early_param("acpi", parse_acpi);
55
56 /*
57 * acpi_fadt_sanity_check() - Check FADT presence and carry out sanity
58 * checks on it
59 *
60 * Return 0 on success, <0 on failure
61 */
62 static int __init acpi_fadt_sanity_check(void)
63 {
64 struct acpi_table_header *table;
65 struct acpi_table_fadt *fadt;
66 acpi_status status;
67 int ret = 0;
68
69 /*
70 * FADT is required on riscv; retrieve it to check its presence
71 * and carry out revision and ACPI HW reduced compliancy tests
72 */
73 status = acpi_get_table(ACPI_SIG_FADT, 0, &table);
74 if (ACPI_FAILURE(status)) {
75 const char *msg = acpi_format_exception(status);
76
77 pr_err("Failed to get FADT table, %s\n", msg);
78 return -ENODEV;
79 }
80
81 fadt = (struct acpi_table_fadt *)table;
82
83 /*
84 * The revision in the table header is the FADT's Major revision. The
85 * FADT also has a minor revision, which is stored in the FADT itself.
86 *
87 * TODO: Currently, we check for 6.5 as the minimum version to check
88 * for HW_REDUCED flag. However, once RISC-V updates are released in
89 * the ACPI spec, we need to update this check for exact minor revision
90 */
91 if (table->revision < 6 || (table->revision == 6 && fadt->minor_revision < 5))
92 pr_err(FW_BUG "Unsupported FADT revision %d.%d, should be 6.5+\n",
93 table->revision, fadt->minor_revision);
94
95 if (!(fadt->flags & ACPI_FADT_HW_REDUCED)) {
96 pr_err("FADT not ACPI hardware reduced compliant\n");
97 ret = -EINVAL;
98 }
99
100 /*
101 * acpi_get_table() creates FADT table mapping that
102 * should be released after parsing and before resuming boot
103 */
104 acpi_put_table(table);
105 return ret;
106 }
107
108 /*
109 * acpi_boot_table_init() called from setup_arch(), always.
110 * 1. find RSDP and get its address, and then find XSDT
111 * 2. extract all tables and checksums them all
112 * 3. check ACPI FADT HW reduced flag
113 *
114 * We can parse ACPI boot-time tables such as MADT after
115 * this function is called.
116 *
117 * On return ACPI is enabled if either:
118 *
119 * - ACPI tables are initialized and sanity checks passed
120 * - acpi=force was passed in the command line and ACPI was not disabled
121 * explicitly through acpi=off command line parameter
122 *
123 * ACPI is disabled on function return otherwise
124 */
125 void __init acpi_boot_table_init(void)
126 {
127 /*
128 * Enable ACPI instead of device tree unless
129 * - ACPI has been disabled explicitly (acpi=off), or
130 * - firmware has not populated ACPI ptr in EFI system table
131 * and ACPI has not been [force] enabled (acpi=on|force)
132 */
133 if (param_acpi_off ||
134 (!param_acpi_on && !param_acpi_force &&
135 efi.acpi20 == EFI_INVALID_TABLE_ADDR))
136 goto done;
137
138 /*
139 * ACPI is disabled at this point. Enable it in order to parse
140 * the ACPI tables and carry out sanity checks
141 */
142 enable_acpi();
143
144 /*
145 * If ACPI tables are initialized and FADT sanity checks passed,
146 * leave ACPI enabled and carry on booting; otherwise disable ACPI
147 * on initialization error.
148 * If acpi=force was passed on the command line it forces ACPI
149 * to be enabled even if its initialization failed.
150 */
151 if (acpi_table_init() || acpi_fadt_sanity_check()) {
152 pr_err("Failed to init ACPI tables\n");
153 if (!param_acpi_force)
154 disable_acpi();
155 }
156
157 done:
158 if (acpi_disabled) {
159 if (earlycon_acpi_spcr_enable)
160 early_init_dt_scan_chosen_stdout();
161 } else {
162 acpi_parse_spcr(earlycon_acpi_spcr_enable, true);
163 }
164 }
165
166 static int acpi_parse_madt_rintc(union acpi_subtable_headers *header, const unsigned long end)
167 {
168 struct acpi_madt_rintc *rintc = (struct acpi_madt_rintc *)header;
169 int cpuid;
170
171 if (!(rintc->flags & ACPI_MADT_ENABLED))
172 return 0;
173
174 cpuid = riscv_hartid_to_cpuid(rintc->hart_id);
175 /*
176 * When CONFIG_SMP is disabled, mapping won't be created for
177 * all cpus.
178 * CPUs more than num_possible_cpus, will be ignored.
179 */
180 if (cpuid >= 0 && cpuid < num_possible_cpus())
181 cpu_madt_rintc[cpuid] = *rintc;
182
183 return 0;
184 }
185
186 /*
187 * Instead of parsing (and freeing) the ACPI table, cache
188 * the RINTC structures since they are frequently used
189 * like in cpuinfo.
190 */
191 void __init acpi_init_rintc_map(void)
192 {
193 if (acpi_table_parse_madt(ACPI_MADT_TYPE_RINTC, acpi_parse_madt_rintc, 0) <= 0) {
194 pr_err("No valid RINTC entries exist\n");
195 BUG();
196 }
197 }
198
199 struct acpi_madt_rintc *acpi_cpu_get_madt_rintc(int cpu)
200 {
201 return &cpu_madt_rintc[cpu];
202 }
203
204 /*
205 * __acpi_map_table() will be called before paging_init(), so early_ioremap()
206 * or early_memremap() should be called here to for ACPI table mapping.
207 */
208 void __init __iomem *__acpi_map_table(unsigned long phys, unsigned long size)
209 {
210 if (!size)
211 return NULL;
212
213 return early_ioremap(phys, size);
214 }
215
216 void __init __acpi_unmap_table(void __iomem *map, unsigned long size)
217 {
218 if (!map || !size)
219 return;
220
221 early_iounmap(map, size);
222 }
223
224 void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size)
225 {
226 efi_memory_desc_t *md, *region = NULL;
227 pgprot_t prot;
228
229 if (WARN_ON_ONCE(!efi_enabled(EFI_MEMMAP)))
230 return NULL;
231
232 for_each_efi_memory_desc(md) {
233 u64 end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT);
234
235 if (phys < md->phys_addr || phys >= end)
236 continue;
237
238 if (phys + size > end) {
239 pr_warn(FW_BUG "requested region covers multiple EFI memory regions\n");
240 return NULL;
241 }
242 region = md;
243 break;
244 }
245
246 /*
247 * It is fine for AML to remap regions that are not represented in the
248 * EFI memory map at all, as it only describes normal memory, and MMIO
249 * regions that require a virtual mapping to make them accessible to
250 * the EFI runtime services.
251 */
252 prot = PAGE_KERNEL_IO;
253 if (region) {
254 switch (region->type) {
255 case EFI_LOADER_CODE:
256 case EFI_LOADER_DATA:
257 case EFI_BOOT_SERVICES_CODE:
258 case EFI_BOOT_SERVICES_DATA:
259 case EFI_CONVENTIONAL_MEMORY:
260 case EFI_PERSISTENT_MEMORY:
261 if (memblock_is_map_memory(phys) ||
262 !memblock_is_region_memory(phys, size)) {
263 pr_warn(FW_BUG "requested region covers kernel memory\n");
264 return NULL;
265 }
266
267 /*
268 * Mapping kernel memory is permitted if the region in
269 * question is covered by a single memblock with the
270 * NOMAP attribute set: this enables the use of ACPI
271 * table overrides passed via initramfs.
272 * This particular use case only requires read access.
273 */
274 fallthrough;
275
276 case EFI_RUNTIME_SERVICES_CODE:
277 /*
278 * This would be unusual, but not problematic per se,
279 * as long as we take care not to create a writable
280 * mapping for executable code.
281 */
282 prot = PAGE_KERNEL_RO;
283 break;
284
285 case EFI_ACPI_RECLAIM_MEMORY:
286 /*
287 * ACPI reclaim memory is used to pass firmware tables
288 * and other data that is intended for consumption by
289 * the OS only, which may decide it wants to reclaim
290 * that memory and use it for something else. We never
291 * do that, but we usually add it to the linear map
292 * anyway, in which case we should use the existing
293 * mapping.
294 */
295 if (memblock_is_map_memory(phys))
296 return (void __iomem *)__va(phys);
297 fallthrough;
298
299 default:
300 if (region->attribute & EFI_MEMORY_WB)
301 prot = PAGE_KERNEL;
302 else if ((region->attribute & EFI_MEMORY_WC) ||
303 (region->attribute & EFI_MEMORY_WT))
304 prot = pgprot_writecombine(PAGE_KERNEL);
305 }
306 }
307
308 return ioremap_prot(phys, size, pgprot_val(prot));
309 }
310
311 #ifdef CONFIG_PCI
312
313 /*
314 * These interfaces are defined just to enable building ACPI core.
315 * TODO: Update it with actual implementation when external interrupt
316 * controller support is added in RISC-V ACPI.
317 */
318 int raw_pci_read(unsigned int domain, unsigned int bus, unsigned int devfn,
319 int reg, int len, u32 *val)
320 {
321 return PCIBIOS_DEVICE_NOT_FOUND;
322 }
323
324 int raw_pci_write(unsigned int domain, unsigned int bus, unsigned int devfn,
325 int reg, int len, u32 val)
326 {
327 return PCIBIOS_DEVICE_NOT_FOUND;
328 }
329
330 int acpi_pci_bus_find_domain_nr(struct pci_bus *bus)
331 {
332 return -1;
333 }
334
335 struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
336 {
337 return NULL;
338 }
339 #endif /* CONFIG_PCI */
340
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