1 /*- 2 * Copyright (c) 2001 Michael Smith <msmith@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 #include <stand.h> 29 #include <machine/stdarg.h> 30 #include <bootstrap.h> 31 #include <btxv86.h> 32 #include "libi386.h" 33 34 #include "platform/acfreebsd.h" 35 #include "acconfig.h" 36 #define ACPI_SYSTEM_XFACE 37 #include "actypes.h" 38 #include "actbl.h" 39 40 /* 41 * Detect ACPI and export information about the ACPI BIOS into the 42 * environment. 43 */ 44 45 static ACPI_TABLE_RSDP *biosacpi_find_rsdp(void); 46 static ACPI_TABLE_RSDP *biosacpi_search_rsdp(char *base, int length); 47 48 #define RSDP_CHECKSUM_LENGTH 20 49 50 void 51 biosacpi_detect(void) 52 { 53 ACPI_TABLE_RSDP *rsdp; 54 char buf[24]; 55 int revision; 56 57 feature_enable(FEATURE_EARLY_ACPI); 58 59 /* locate and validate the RSDP */ 60 if ((rsdp = biosacpi_find_rsdp()) == NULL) 61 return; 62 63 /* 64 * Report the RSDP to the kernel. While this can be found with 65 * a BIOS boot, the RSDP may be elsewhere when booted from UEFI. 66 */ 67 sprintf(buf, "0x%08x", VTOP(rsdp)); 68 setenv("acpi.rsdp", buf, 1); 69 revision = rsdp->Revision; 70 if (revision == 0) 71 revision = 1; 72 sprintf(buf, "%d", revision); 73 setenv("acpi.revision", buf, 1); 74 strncpy(buf, rsdp->OemId, sizeof(rsdp->OemId)); 75 buf[sizeof(rsdp->OemId)] = '\0'; 76 setenv("acpi.oem", buf, 1); 77 sprintf(buf, "0x%08x", rsdp->RsdtPhysicalAddress); 78 setenv("acpi.rsdt", buf, 1); 79 if (revision >= 2) { 80 /* XXX extended checksum? */ 81 sprintf(buf, "0x%016llx", rsdp->XsdtPhysicalAddress); 82 setenv("acpi.xsdt", buf, 1); 83 sprintf(buf, "%d", rsdp->Length); 84 setenv("acpi.xsdt_length", buf, 1); 85 } 86 } 87 88 /* 89 * Find the RSDP in low memory. See section 5.2.2 of the ACPI spec. 90 */ 91 static ACPI_TABLE_RSDP * 92 biosacpi_find_rsdp(void) 93 { 94 ACPI_TABLE_RSDP *rsdp; 95 uint16_t *addr; 96 97 /* EBDA is the 1 KB addressed by the 16 bit pointer at 0x40E. */ 98 addr = (uint16_t *)PTOV(0x40E); 99 if ((rsdp = biosacpi_search_rsdp((char *)(*addr << 4), 0x400)) != NULL) 100 return (rsdp); 101 102 /* Check the upper memory BIOS space, 0xe0000 - 0xfffff. */ 103 if ((rsdp = biosacpi_search_rsdp((char *)0xe0000, 0x20000)) != NULL) 104 return (rsdp); 105 106 return (NULL); 107 } 108 109 static ACPI_TABLE_RSDP * 110 biosacpi_search_rsdp(char *base, int length) 111 { 112 ACPI_TABLE_RSDP *rsdp; 113 uint8_t *cp, sum; 114 int ofs, idx; 115 116 /* search on 16-byte boundaries */ 117 for (ofs = 0; ofs < length; ofs += 16) { 118 rsdp = (ACPI_TABLE_RSDP *)PTOV(base + ofs); 119 120 /* compare signature, validate checksum */ 121 if (!strncmp(rsdp->Signature, ACPI_SIG_RSDP, strlen(ACPI_SIG_RSDP))) { 122 cp = (uint8_t *)rsdp; 123 sum = 0; 124 for (idx = 0; idx < RSDP_CHECKSUM_LENGTH; idx++) 125 sum += *(cp + idx); 126 if (sum != 0) 127 continue; 128 return(rsdp); 129 } 130 } 131 return(NULL); 132 } 133