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/*
* Copyright (c) 1997-1998 University of Utah and the Flux Group.
* All rights reserved.
*
* This file is part of the Flux OSKit. The OSKit is free software, also known
* as "open source;" you can redistribute it and/or modify it under the terms
* of the GNU General Public License (GPL), version 2, as published by the Free
* Software Foundation (FSF). To explore alternate licensing terms, contact
* the University of Utah at csl-dist@cs.utah.edu or +1-801-585-3271.
*
* The OSKit 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 GPL for more details. You should have
* received a copy of the GPL along with the OSKit; see the file COPYING. If
* not, write to the FSF, 59 Temple Place #330, Boston, MA 02111-1307, USA.
*/
/*
* Default implementation of x86-specific fdev functions
* to access 32-bit BIOS (BIOS32) services such as Plug & Play and PCI.
*/
#include <oskit/page.h>
#include <oskit/error.h>
#include <oskit/x86/types.h>
#include <oskit/x86/far_ptr.h>
#include <oskit/x86/proc_reg.h>
#include <oskit/x86/pc/bios32.h>
#include <oskit/dev/error.h>
#include <oskit/dev/dev.h>
static void *e0000_va;
static struct bios32 *directory;
static void *entry_page_va;
oskit_error_t
oskit_bios32_find_service(unsigned service, oskit_addr_t *out_start,
oskit_addr_t *out_length, oskit_addr_t *out_entry)
{
oskit_error_t rc;
/* Map the BIOS memory area from E0000 to FFFFF */
if (e0000_va == 0) {
rc = osenv_mem_map_phys(0xe0000, 0x20000, &e0000_va, 0);
if (rc)
return rc;
}
/* Find the BIOS32 service directory structure */
if (directory == 0) {
struct bios32 *dir;
for (dir = e0000_va; ; dir++) {
unsigned char sum;
int i;
if (dir == e0000_va + 0x20000)
return OSKIT_E_DEV_NO_BIOS32;
if (dir->signature != BIOS32_SIGNATURE)
continue;
/* Make sure the checksum adds up */
sum = 0;
for (i = dir->length * 16 - 1; i >= 0; i--)
sum += ((unsigned char*)dir)[i];
if (sum != 0)
continue;
/* Make sure this is the revision we want */
if (dir->revision != 0) {
osenv_log(OSENV_LOG_WARNING,
"BIOS32 Service Directory structure "
"with unsupported revision %d at %08x",
dir->revision,
(void*)dir - e0000_va + 0xe0000);
continue;
}
/* Found it! */
directory = dir;
break;
}
}
/*
* Map two physical pages into our address space
* starting with the one containing the entrypoint,
* as specified in the BIOS32 specification.
* Note that the entrypoint itself isn't necessarily
* in the e0000-ffff0 range that the directory struct is in.
*/
if (entry_page_va == 0) {
oskit_addr_t entry_page_pa = directory->entry & ~PAGE_MASK;
rc = osenv_mem_map_phys(entry_page_pa, PAGE_SIZE * 2,
&entry_page_va, 0);
if (rc)
return rc;
}
/*
* Call the BIOS32 service directory entrypoint
*/
{
struct far_pointer_32 call_vector;
unsigned char retcode;
call_vector.seg = get_cs();
call_vector.ofs = (oskit_addr_t)entry_page_va +
(directory->entry & PAGE_MASK);
asm volatile("lcall (%6)"
: "=a" (retcode),
"=b" (*out_start),
"=c" (*out_length),
"=d" (*out_entry)
: "a" (service),
"b" (0),
"r" (&call_vector));
if (retcode != 0) {
if (retcode == 0x80)
return OSKIT_E_DEV_NO_BIOS32_SERVICE;
return OSKIT_E_UNEXPECTED;
}
return 0;
}
}
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