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 <stand.h> 28 #include <machine/stdarg.h> 29 #include <bootstrap.h> 30 #include <btxv86.h> 31 #include "libi386.h" 32 33 #include "platform/acfreebsd.h" 34 #include "acconfig.h" 35 #define ACPI_SYSTEM_XFACE 36 #include "actypes.h" 37 #include "actbl.h" 38 39 /* 40 * Detect ACPI and export information about the ACPI BIOS into the 41 * environment. 42 */ 43 44 static ACPI_TABLE_RSDP *biosacpi_find_rsdp(void); 45 static ACPI_TABLE_RSDP *biosacpi_search_rsdp(char *base, int length); 46 47 #define RSDP_CHECKSUM_LENGTH 20 48 49 void 50 biosacpi_detect(void) 51 { 52 ACPI_TABLE_RSDP *rsdp; 53 char buf[24]; 54 int revision; 55 56 feature_enable(FEATURE_EARLY_ACPI); 57 58 /* locate and validate the RSDP */ 59 if ((rsdp = biosacpi_find_rsdp()) == NULL) 60 return; 61 62 /* 63 * Report the RSDP to the kernel. While this can be found with 64 * a BIOS boot, the RSDP may be elsewhere when booted from UEFI. 65 */ 66 sprintf(buf, "0x%08x", VTOP(rsdp)); 67 setenv("acpi.rsdp", buf, 1); 68 revision = rsdp->Revision; 69 if (revision == 0) 70 revision = 1; 71 sprintf(buf, "%d", revision); 72 setenv("acpi.revision", buf, 1); 73 strncpy(buf, rsdp->OemId, sizeof(rsdp->OemId)); 74 buf[sizeof(rsdp->OemId)] = '\0'; 75 setenv("acpi.oem", buf, 1); 76 sprintf(buf, "0x%08x", rsdp->RsdtPhysicalAddress); 77 setenv("acpi.rsdt", buf, 1); 78 if (revision >= 2) { 79 /* XXX extended checksum? */ 80 sprintf(buf, "0x%016llx", rsdp->XsdtPhysicalAddress); 81 setenv("acpi.xsdt", buf, 1); 82 sprintf(buf, "%d", rsdp->Length); 83 setenv("acpi.xsdt_length", buf, 1); 84 } 85 } 86 87 /* 88 * Find the RSDP in low memory. See section 5.2.2 of the ACPI spec. 89 */ 90 static ACPI_TABLE_RSDP * 91 biosacpi_find_rsdp(void) 92 { 93 ACPI_TABLE_RSDP *rsdp; 94 uint16_t *addr; 95 96 /* EBDA is the 1 KB addressed by the 16 bit pointer at 0x40E. */ 97 addr = (uint16_t *)PTOV(0x40E); 98 if ((rsdp = biosacpi_search_rsdp((char *)(*addr << 4), 0x400)) != NULL) 99 return (rsdp); 100 101 /* Check the upper memory BIOS space, 0xe0000 - 0xfffff. */ 102 if ((rsdp = biosacpi_search_rsdp((char *)0xe0000, 0x20000)) != NULL) 103 return (rsdp); 104 105 return (NULL); 106 } 107 108 static ACPI_TABLE_RSDP * 109 biosacpi_search_rsdp(char *base, int length) 110 { 111 ACPI_TABLE_RSDP *rsdp; 112 uint8_t *cp, sum; 113 int ofs, idx; 114 115 /* search on 16-byte boundaries */ 116 for (ofs = 0; ofs < length; ofs += 16) { 117 rsdp = (ACPI_TABLE_RSDP *)PTOV(base + ofs); 118 119 /* compare signature, validate checksum */ 120 if (!strncmp(rsdp->Signature, ACPI_SIG_RSDP, strlen(ACPI_SIG_RSDP))) { 121 cp = (uint8_t *)rsdp; 122 sum = 0; 123 for (idx = 0; idx < RSDP_CHECKSUM_LENGTH; idx++) 124 sum += *(cp + idx); 125 if (sum != 0) 126 continue; 127 return(rsdp); 128 } 129 } 130 return(NULL); 131 } 132