|  | /* | 
|  | *  acpi_tables.c - ACPI Boot-Time Table Parsing | 
|  | * | 
|  | *  Copyright (C) 2001 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com> | 
|  | * | 
|  | * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | 
|  | * | 
|  | *  This program is free software; you can redistribute it and/or modify | 
|  | *  it under the terms of the GNU General Public License as published by | 
|  | *  the Free Software Foundation; either version 2 of the License, or | 
|  | *  (at your option) any later version. | 
|  | * | 
|  | *  This program is distributed in the hope that it will be useful, | 
|  | *  but WITHOUT ANY WARRANTY; without even the implied warranty of | 
|  | *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the | 
|  | *  GNU General Public License for more details. | 
|  | * | 
|  | *  You should have received a copy of the GNU General Public License | 
|  | *  along with this program; if not, write to the Free Software | 
|  | *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA | 
|  | * | 
|  | * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | 
|  | * | 
|  | */ | 
|  |  | 
|  | #include <linux/init.h> | 
|  | #include <linux/kernel.h> | 
|  | #include <linux/sched.h> | 
|  | #include <linux/smp.h> | 
|  | #include <linux/string.h> | 
|  | #include <linux/types.h> | 
|  | #include <linux/irq.h> | 
|  | #include <linux/errno.h> | 
|  | #include <linux/acpi.h> | 
|  | #include <linux/bootmem.h> | 
|  |  | 
|  | #define PREFIX			"ACPI: " | 
|  |  | 
|  | #define ACPI_MAX_TABLES		128 | 
|  |  | 
|  | static char *acpi_table_signatures[ACPI_TABLE_COUNT] = { | 
|  | [ACPI_TABLE_UNKNOWN] = "????", | 
|  | [ACPI_APIC] = "APIC", | 
|  | [ACPI_BOOT] = "BOOT", | 
|  | [ACPI_DBGP] = "DBGP", | 
|  | [ACPI_DSDT] = "DSDT", | 
|  | [ACPI_ECDT] = "ECDT", | 
|  | [ACPI_ETDT] = "ETDT", | 
|  | [ACPI_FADT] = "FACP", | 
|  | [ACPI_FACS] = "FACS", | 
|  | [ACPI_OEMX] = "OEM", | 
|  | [ACPI_PSDT] = "PSDT", | 
|  | [ACPI_SBST] = "SBST", | 
|  | [ACPI_SLIT] = "SLIT", | 
|  | [ACPI_SPCR] = "SPCR", | 
|  | [ACPI_SRAT] = "SRAT", | 
|  | [ACPI_SSDT] = "SSDT", | 
|  | [ACPI_SPMI] = "SPMI", | 
|  | [ACPI_HPET] = "HPET", | 
|  | [ACPI_MCFG] = "MCFG", | 
|  | }; | 
|  |  | 
|  | static char *mps_inti_flags_polarity[] = { "dfl", "high", "res", "low" }; | 
|  | static char *mps_inti_flags_trigger[] = { "dfl", "edge", "res", "level" }; | 
|  |  | 
|  | /* System Description Table (RSDT/XSDT) */ | 
|  | struct acpi_table_sdt { | 
|  | unsigned long pa; | 
|  | enum acpi_table_id id; | 
|  | unsigned long size; | 
|  | } __attribute__ ((packed)); | 
|  |  | 
|  | static unsigned long sdt_pa;	/* Physical Address */ | 
|  | static unsigned long sdt_count;	/* Table count */ | 
|  |  | 
|  | static struct acpi_table_sdt sdt_entry[ACPI_MAX_TABLES] __initdata; | 
|  |  | 
|  | void acpi_table_print(struct acpi_table_header *header, unsigned long phys_addr) | 
|  | { | 
|  | char *name = NULL; | 
|  |  | 
|  | if (!header) | 
|  | return; | 
|  |  | 
|  | /* Some table signatures aren't good table names */ | 
|  |  | 
|  | if (!strncmp((char *)&header->signature, | 
|  | acpi_table_signatures[ACPI_APIC], | 
|  | sizeof(header->signature))) { | 
|  | name = "MADT"; | 
|  | } else if (!strncmp((char *)&header->signature, | 
|  | acpi_table_signatures[ACPI_FADT], | 
|  | sizeof(header->signature))) { | 
|  | name = "FADT"; | 
|  | } else | 
|  | name = header->signature; | 
|  |  | 
|  | printk(KERN_DEBUG PREFIX | 
|  | "%.4s (v%3.3d %6.6s %8.8s 0x%08x %.4s 0x%08x) @ 0x%p\n", name, | 
|  | header->revision, header->oem_id, header->oem_table_id, | 
|  | header->oem_revision, header->asl_compiler_id, | 
|  | header->asl_compiler_revision, (void *)phys_addr); | 
|  | } | 
|  |  | 
|  | void acpi_table_print_madt_entry(acpi_table_entry_header * header) | 
|  | { | 
|  | if (!header) | 
|  | return; | 
|  |  | 
|  | switch (header->type) { | 
|  |  | 
|  | case ACPI_MADT_LAPIC: | 
|  | { | 
|  | struct acpi_table_lapic *p = | 
|  | (struct acpi_table_lapic *)header; | 
|  | printk(KERN_INFO PREFIX | 
|  | "LAPIC (acpi_id[0x%02x] lapic_id[0x%02x] %s)\n", | 
|  | p->acpi_id, p->id, | 
|  | p->flags.enabled ? "enabled" : "disabled"); | 
|  | } | 
|  | break; | 
|  |  | 
|  | case ACPI_MADT_IOAPIC: | 
|  | { | 
|  | struct acpi_table_ioapic *p = | 
|  | (struct acpi_table_ioapic *)header; | 
|  | printk(KERN_INFO PREFIX | 
|  | "IOAPIC (id[0x%02x] address[0x%08x] gsi_base[%d])\n", | 
|  | p->id, p->address, p->global_irq_base); | 
|  | } | 
|  | break; | 
|  |  | 
|  | case ACPI_MADT_INT_SRC_OVR: | 
|  | { | 
|  | struct acpi_table_int_src_ovr *p = | 
|  | (struct acpi_table_int_src_ovr *)header; | 
|  | printk(KERN_INFO PREFIX | 
|  | "INT_SRC_OVR (bus %d bus_irq %d global_irq %d %s %s)\n", | 
|  | p->bus, p->bus_irq, p->global_irq, | 
|  | mps_inti_flags_polarity[p->flags.polarity], | 
|  | mps_inti_flags_trigger[p->flags.trigger]); | 
|  | if (p->flags.reserved) | 
|  | printk(KERN_INFO PREFIX | 
|  | "INT_SRC_OVR unexpected reserved flags: 0x%x\n", | 
|  | p->flags.reserved); | 
|  |  | 
|  | } | 
|  | break; | 
|  |  | 
|  | case ACPI_MADT_NMI_SRC: | 
|  | { | 
|  | struct acpi_table_nmi_src *p = | 
|  | (struct acpi_table_nmi_src *)header; | 
|  | printk(KERN_INFO PREFIX | 
|  | "NMI_SRC (%s %s global_irq %d)\n", | 
|  | mps_inti_flags_polarity[p->flags.polarity], | 
|  | mps_inti_flags_trigger[p->flags.trigger], | 
|  | p->global_irq); | 
|  | } | 
|  | break; | 
|  |  | 
|  | case ACPI_MADT_LAPIC_NMI: | 
|  | { | 
|  | struct acpi_table_lapic_nmi *p = | 
|  | (struct acpi_table_lapic_nmi *)header; | 
|  | printk(KERN_INFO PREFIX | 
|  | "LAPIC_NMI (acpi_id[0x%02x] %s %s lint[0x%x])\n", | 
|  | p->acpi_id, | 
|  | mps_inti_flags_polarity[p->flags.polarity], | 
|  | mps_inti_flags_trigger[p->flags.trigger], | 
|  | p->lint); | 
|  | } | 
|  | break; | 
|  |  | 
|  | case ACPI_MADT_LAPIC_ADDR_OVR: | 
|  | { | 
|  | struct acpi_table_lapic_addr_ovr *p = | 
|  | (struct acpi_table_lapic_addr_ovr *)header; | 
|  | printk(KERN_INFO PREFIX | 
|  | "LAPIC_ADDR_OVR (address[%p])\n", | 
|  | (void *)(unsigned long)p->address); | 
|  | } | 
|  | break; | 
|  |  | 
|  | case ACPI_MADT_IOSAPIC: | 
|  | { | 
|  | struct acpi_table_iosapic *p = | 
|  | (struct acpi_table_iosapic *)header; | 
|  | printk(KERN_INFO PREFIX | 
|  | "IOSAPIC (id[0x%x] address[%p] gsi_base[%d])\n", | 
|  | p->id, (void *)(unsigned long)p->address, | 
|  | p->global_irq_base); | 
|  | } | 
|  | break; | 
|  |  | 
|  | case ACPI_MADT_LSAPIC: | 
|  | { | 
|  | struct acpi_table_lsapic *p = | 
|  | (struct acpi_table_lsapic *)header; | 
|  | printk(KERN_INFO PREFIX | 
|  | "LSAPIC (acpi_id[0x%02x] lsapic_id[0x%02x] lsapic_eid[0x%02x] %s)\n", | 
|  | p->acpi_id, p->id, p->eid, | 
|  | p->flags.enabled ? "enabled" : "disabled"); | 
|  | } | 
|  | break; | 
|  |  | 
|  | case ACPI_MADT_PLAT_INT_SRC: | 
|  | { | 
|  | struct acpi_table_plat_int_src *p = | 
|  | (struct acpi_table_plat_int_src *)header; | 
|  | printk(KERN_INFO PREFIX | 
|  | "PLAT_INT_SRC (%s %s type[0x%x] id[0x%04x] eid[0x%x] iosapic_vector[0x%x] global_irq[0x%x]\n", | 
|  | mps_inti_flags_polarity[p->flags.polarity], | 
|  | mps_inti_flags_trigger[p->flags.trigger], | 
|  | p->type, p->id, p->eid, p->iosapic_vector, | 
|  | p->global_irq); | 
|  | } | 
|  | break; | 
|  |  | 
|  | default: | 
|  | printk(KERN_WARNING PREFIX | 
|  | "Found unsupported MADT entry (type = 0x%x)\n", | 
|  | header->type); | 
|  | break; | 
|  | } | 
|  | } | 
|  |  | 
|  | static int | 
|  | acpi_table_compute_checksum(void *table_pointer, unsigned long length) | 
|  | { | 
|  | u8 *p = table_pointer; | 
|  | unsigned long remains = length; | 
|  | unsigned long sum = 0; | 
|  |  | 
|  | if (!p || !length) | 
|  | return -EINVAL; | 
|  |  | 
|  | while (remains--) | 
|  | sum += *p++; | 
|  |  | 
|  | return (sum & 0xFF); | 
|  | } | 
|  |  | 
|  | /* | 
|  | * acpi_get_table_header_early() | 
|  | * for acpi_blacklisted(), acpi_table_get_sdt() | 
|  | */ | 
|  | int __init | 
|  | acpi_get_table_header_early(enum acpi_table_id id, | 
|  | struct acpi_table_header **header) | 
|  | { | 
|  | unsigned int i; | 
|  | enum acpi_table_id temp_id; | 
|  |  | 
|  | /* DSDT is different from the rest */ | 
|  | if (id == ACPI_DSDT) | 
|  | temp_id = ACPI_FADT; | 
|  | else | 
|  | temp_id = id; | 
|  |  | 
|  | /* Locate the table. */ | 
|  |  | 
|  | for (i = 0; i < sdt_count; i++) { | 
|  | if (sdt_entry[i].id != temp_id) | 
|  | continue; | 
|  | *header = (void *) | 
|  | __acpi_map_table(sdt_entry[i].pa, sdt_entry[i].size); | 
|  | if (!*header) { | 
|  | printk(KERN_WARNING PREFIX "Unable to map %s\n", | 
|  | acpi_table_signatures[temp_id]); | 
|  | return -ENODEV; | 
|  | } | 
|  | break; | 
|  | } | 
|  |  | 
|  | if (!*header) { | 
|  | printk(KERN_WARNING PREFIX "%s not present\n", | 
|  | acpi_table_signatures[id]); | 
|  | return -ENODEV; | 
|  | } | 
|  |  | 
|  | /* Map the DSDT header via the pointer in the FADT */ | 
|  | if (id == ACPI_DSDT) { | 
|  | struct fadt_descriptor *fadt = | 
|  | (struct fadt_descriptor *)*header; | 
|  |  | 
|  | if (fadt->revision == 3 && fadt->Xdsdt) { | 
|  | *header = (void *)__acpi_map_table(fadt->Xdsdt, | 
|  | sizeof(struct | 
|  | acpi_table_header)); | 
|  | } else if (fadt->V1_dsdt) { | 
|  | *header = (void *)__acpi_map_table(fadt->V1_dsdt, | 
|  | sizeof(struct | 
|  | acpi_table_header)); | 
|  | } else | 
|  | *header = NULL; | 
|  |  | 
|  | if (!*header) { | 
|  | printk(KERN_WARNING PREFIX "Unable to map DSDT\n"); | 
|  | return -ENODEV; | 
|  | } | 
|  | } | 
|  |  | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | int __init | 
|  | acpi_table_parse_madt_family(enum acpi_table_id id, | 
|  | unsigned long madt_size, | 
|  | int entry_id, | 
|  | acpi_madt_entry_handler handler, | 
|  | unsigned int max_entries) | 
|  | { | 
|  | void *madt = NULL; | 
|  | acpi_table_entry_header *entry; | 
|  | unsigned int count = 0; | 
|  | unsigned long madt_end; | 
|  | unsigned int i; | 
|  |  | 
|  | if (!handler) | 
|  | return -EINVAL; | 
|  |  | 
|  | /* Locate the MADT (if exists). There should only be one. */ | 
|  |  | 
|  | for (i = 0; i < sdt_count; i++) { | 
|  | if (sdt_entry[i].id != id) | 
|  | continue; | 
|  | madt = (void *) | 
|  | __acpi_map_table(sdt_entry[i].pa, sdt_entry[i].size); | 
|  | if (!madt) { | 
|  | printk(KERN_WARNING PREFIX "Unable to map %s\n", | 
|  | acpi_table_signatures[id]); | 
|  | return -ENODEV; | 
|  | } | 
|  | break; | 
|  | } | 
|  |  | 
|  | if (!madt) { | 
|  | printk(KERN_WARNING PREFIX "%s not present\n", | 
|  | acpi_table_signatures[id]); | 
|  | return -ENODEV; | 
|  | } | 
|  |  | 
|  | madt_end = (unsigned long)madt + sdt_entry[i].size; | 
|  |  | 
|  | /* Parse all entries looking for a match. */ | 
|  |  | 
|  | entry = (acpi_table_entry_header *) | 
|  | ((unsigned long)madt + madt_size); | 
|  |  | 
|  | while (((unsigned long)entry) + sizeof(acpi_table_entry_header) < | 
|  | madt_end) { | 
|  | if (entry->type == entry_id | 
|  | && (!max_entries || count++ < max_entries)) | 
|  | if (handler(entry, madt_end)) | 
|  | return -EINVAL; | 
|  |  | 
|  | entry = (acpi_table_entry_header *) | 
|  | ((unsigned long)entry + entry->length); | 
|  | } | 
|  | if (max_entries && count > max_entries) { | 
|  | printk(KERN_WARNING PREFIX "[%s:0x%02x] ignored %i entries of " | 
|  | "%i found\n", acpi_table_signatures[id], entry_id, | 
|  | count - max_entries, count); | 
|  | } | 
|  |  | 
|  | return count; | 
|  | } | 
|  |  | 
|  | int __init | 
|  | acpi_table_parse_madt(enum acpi_madt_entry_id id, | 
|  | acpi_madt_entry_handler handler, unsigned int max_entries) | 
|  | { | 
|  | return acpi_table_parse_madt_family(ACPI_APIC, | 
|  | sizeof(struct acpi_table_madt), id, | 
|  | handler, max_entries); | 
|  | } | 
|  |  | 
|  | int __init acpi_table_parse(enum acpi_table_id id, acpi_table_handler handler) | 
|  | { | 
|  | int count = 0; | 
|  | unsigned int i = 0; | 
|  |  | 
|  | if (!handler) | 
|  | return -EINVAL; | 
|  |  | 
|  | for (i = 0; i < sdt_count; i++) { | 
|  | if (sdt_entry[i].id != id) | 
|  | continue; | 
|  | count++; | 
|  | if (count == 1) | 
|  | handler(sdt_entry[i].pa, sdt_entry[i].size); | 
|  |  | 
|  | else | 
|  | printk(KERN_WARNING PREFIX | 
|  | "%d duplicate %s table ignored.\n", count, | 
|  | acpi_table_signatures[id]); | 
|  | } | 
|  |  | 
|  | return count; | 
|  | } | 
|  |  | 
|  | static int __init acpi_table_get_sdt(struct acpi_table_rsdp *rsdp) | 
|  | { | 
|  | struct acpi_table_header *header = NULL; | 
|  | unsigned int i, id = 0; | 
|  |  | 
|  | if (!rsdp) | 
|  | return -EINVAL; | 
|  |  | 
|  | /* First check XSDT (but only on ACPI 2.0-compatible systems) */ | 
|  |  | 
|  | if ((rsdp->revision >= 2) && | 
|  | (((struct acpi20_table_rsdp *)rsdp)->xsdt_address)) { | 
|  |  | 
|  | struct acpi_table_xsdt *mapped_xsdt = NULL; | 
|  |  | 
|  | sdt_pa = ((struct acpi20_table_rsdp *)rsdp)->xsdt_address; | 
|  |  | 
|  | /* map in just the header */ | 
|  | header = (struct acpi_table_header *) | 
|  | __acpi_map_table(sdt_pa, sizeof(struct acpi_table_header)); | 
|  |  | 
|  | if (!header) { | 
|  | printk(KERN_WARNING PREFIX | 
|  | "Unable to map XSDT header\n"); | 
|  | return -ENODEV; | 
|  | } | 
|  |  | 
|  | /* remap in the entire table before processing */ | 
|  | mapped_xsdt = (struct acpi_table_xsdt *) | 
|  | __acpi_map_table(sdt_pa, header->length); | 
|  | if (!mapped_xsdt) { | 
|  | printk(KERN_WARNING PREFIX "Unable to map XSDT\n"); | 
|  | return -ENODEV; | 
|  | } | 
|  | header = &mapped_xsdt->header; | 
|  |  | 
|  | if (strncmp(header->signature, "XSDT", 4)) { | 
|  | printk(KERN_WARNING PREFIX | 
|  | "XSDT signature incorrect\n"); | 
|  | return -ENODEV; | 
|  | } | 
|  |  | 
|  | if (acpi_table_compute_checksum(header, header->length)) { | 
|  | printk(KERN_WARNING PREFIX "Invalid XSDT checksum\n"); | 
|  | return -ENODEV; | 
|  | } | 
|  |  | 
|  | sdt_count = | 
|  | (header->length - sizeof(struct acpi_table_header)) >> 3; | 
|  | if (sdt_count > ACPI_MAX_TABLES) { | 
|  | printk(KERN_WARNING PREFIX | 
|  | "Truncated %lu XSDT entries\n", | 
|  | (sdt_count - ACPI_MAX_TABLES)); | 
|  | sdt_count = ACPI_MAX_TABLES; | 
|  | } | 
|  |  | 
|  | for (i = 0; i < sdt_count; i++) | 
|  | sdt_entry[i].pa = (unsigned long)mapped_xsdt->entry[i]; | 
|  | } | 
|  |  | 
|  | /* Then check RSDT */ | 
|  |  | 
|  | else if (rsdp->rsdt_address) { | 
|  |  | 
|  | struct acpi_table_rsdt *mapped_rsdt = NULL; | 
|  |  | 
|  | sdt_pa = rsdp->rsdt_address; | 
|  |  | 
|  | /* map in just the header */ | 
|  | header = (struct acpi_table_header *) | 
|  | __acpi_map_table(sdt_pa, sizeof(struct acpi_table_header)); | 
|  | if (!header) { | 
|  | printk(KERN_WARNING PREFIX | 
|  | "Unable to map RSDT header\n"); | 
|  | return -ENODEV; | 
|  | } | 
|  |  | 
|  | /* remap in the entire table before processing */ | 
|  | mapped_rsdt = (struct acpi_table_rsdt *) | 
|  | __acpi_map_table(sdt_pa, header->length); | 
|  | if (!mapped_rsdt) { | 
|  | printk(KERN_WARNING PREFIX "Unable to map RSDT\n"); | 
|  | return -ENODEV; | 
|  | } | 
|  | header = &mapped_rsdt->header; | 
|  |  | 
|  | if (strncmp(header->signature, "RSDT", 4)) { | 
|  | printk(KERN_WARNING PREFIX | 
|  | "RSDT signature incorrect\n"); | 
|  | return -ENODEV; | 
|  | } | 
|  |  | 
|  | if (acpi_table_compute_checksum(header, header->length)) { | 
|  | printk(KERN_WARNING PREFIX "Invalid RSDT checksum\n"); | 
|  | return -ENODEV; | 
|  | } | 
|  |  | 
|  | sdt_count = | 
|  | (header->length - sizeof(struct acpi_table_header)) >> 2; | 
|  | if (sdt_count > ACPI_MAX_TABLES) { | 
|  | printk(KERN_WARNING PREFIX | 
|  | "Truncated %lu RSDT entries\n", | 
|  | (sdt_count - ACPI_MAX_TABLES)); | 
|  | sdt_count = ACPI_MAX_TABLES; | 
|  | } | 
|  |  | 
|  | for (i = 0; i < sdt_count; i++) | 
|  | sdt_entry[i].pa = (unsigned long)mapped_rsdt->entry[i]; | 
|  | } | 
|  |  | 
|  | else { | 
|  | printk(KERN_WARNING PREFIX | 
|  | "No System Description Table (RSDT/XSDT) specified in RSDP\n"); | 
|  | return -ENODEV; | 
|  | } | 
|  |  | 
|  | acpi_table_print(header, sdt_pa); | 
|  |  | 
|  | for (i = 0; i < sdt_count; i++) { | 
|  |  | 
|  | /* map in just the header */ | 
|  | header = (struct acpi_table_header *) | 
|  | __acpi_map_table(sdt_entry[i].pa, | 
|  | sizeof(struct acpi_table_header)); | 
|  | if (!header) | 
|  | continue; | 
|  |  | 
|  | /* remap in the entire table before processing */ | 
|  | header = (struct acpi_table_header *) | 
|  | __acpi_map_table(sdt_entry[i].pa, header->length); | 
|  | if (!header) | 
|  | continue; | 
|  |  | 
|  | acpi_table_print(header, sdt_entry[i].pa); | 
|  |  | 
|  | if (acpi_table_compute_checksum(header, header->length)) { | 
|  | printk(KERN_WARNING "  >>> ERROR: Invalid checksum\n"); | 
|  | continue; | 
|  | } | 
|  |  | 
|  | sdt_entry[i].size = header->length; | 
|  |  | 
|  | for (id = 0; id < ACPI_TABLE_COUNT; id++) { | 
|  | if (!strncmp((char *)&header->signature, | 
|  | acpi_table_signatures[id], | 
|  | sizeof(header->signature))) { | 
|  | sdt_entry[i].id = id; | 
|  | } | 
|  | } | 
|  | } | 
|  |  | 
|  | /* | 
|  | * The DSDT is *not* in the RSDT (why not? no idea.) but we want | 
|  | * to print its info, because this is what people usually blacklist | 
|  | * against. Unfortunately, we don't know the phys_addr, so just | 
|  | * print 0. Maybe no one will notice. | 
|  | */ | 
|  | if (!acpi_get_table_header_early(ACPI_DSDT, &header)) | 
|  | acpi_table_print(header, 0); | 
|  |  | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * acpi_table_init() | 
|  | * | 
|  | * find RSDP, find and checksum SDT/XSDT. | 
|  | * checksum all tables, print SDT/XSDT | 
|  | * | 
|  | * result: sdt_entry[] is initialized | 
|  | */ | 
|  |  | 
|  | int __init acpi_table_init(void) | 
|  | { | 
|  | struct acpi_table_rsdp *rsdp = NULL; | 
|  | unsigned long rsdp_phys = 0; | 
|  | int result = 0; | 
|  |  | 
|  | /* Locate and map the Root System Description Table (RSDP) */ | 
|  |  | 
|  | rsdp_phys = acpi_find_rsdp(); | 
|  | if (!rsdp_phys) { | 
|  | printk(KERN_ERR PREFIX "Unable to locate RSDP\n"); | 
|  | return -ENODEV; | 
|  | } | 
|  |  | 
|  | rsdp = (struct acpi_table_rsdp *)__acpi_map_table(rsdp_phys, | 
|  | sizeof(struct acpi_table_rsdp)); | 
|  | if (!rsdp) { | 
|  | printk(KERN_WARNING PREFIX "Unable to map RSDP\n"); | 
|  | return -ENODEV; | 
|  | } | 
|  |  | 
|  | printk(KERN_DEBUG PREFIX | 
|  | "RSDP (v%3.3d %6.6s                                ) @ 0x%p\n", | 
|  | rsdp->revision, rsdp->oem_id, (void *)rsdp_phys); | 
|  |  | 
|  | if (rsdp->revision < 2) | 
|  | result = | 
|  | acpi_table_compute_checksum(rsdp, | 
|  | sizeof(struct acpi_table_rsdp)); | 
|  | else | 
|  | result = | 
|  | acpi_table_compute_checksum(rsdp, | 
|  | ((struct acpi20_table_rsdp *) | 
|  | rsdp)->length); | 
|  |  | 
|  | if (result) { | 
|  | printk(KERN_WARNING "  >>> ERROR: Invalid checksum\n"); | 
|  | return -ENODEV; | 
|  | } | 
|  |  | 
|  | /* Locate and map the System Description table (RSDT/XSDT) */ | 
|  |  | 
|  | if (acpi_table_get_sdt(rsdp)) | 
|  | return -ENODEV; | 
|  |  | 
|  | return 0; | 
|  | } |