arch/riscv/kernel/acpi.c

   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  * raw_pci_read/write - Platform-specific PCI config space access.
 315  */
 316 int raw_pci_read(unsigned int domain, unsigned int bus,
 317                  unsigned int devfn, int reg, int len, u32 *val)
 318 {
 319         struct pci_bus *b = pci_find_bus(domain, bus);
 320
 321         if (!b)
 322                 return PCIBIOS_DEVICE_NOT_FOUND;
 323         return b->ops->read(b, devfn, reg, len, val);
 324 }
 325
 326 int raw_pci_write(unsigned int domain, unsigned int bus,
 327                   unsigned int devfn, int reg, int len, u32 val)
 328 {
 329         struct pci_bus *b = pci_find_bus(domain, bus);
 330
 331         if (!b)
 332                 return PCIBIOS_DEVICE_NOT_FOUND;
 333         return b->ops->write(b, devfn, reg, len, val);
 334 }
 335
 336 #endif  /* CONFIG_PCI */