xref: /kernel/linux/linux-6.6/tools/power/cpupower/debug/i386/intel_gsic.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  (C) 2003  Bruno Ducrot
 *  (C) 2004  Dominik Brodowski <linux@dominikbrodowski.de>
 *
 * Based on code found in
 * linux/include/asm-i386/ist.h and linux/arch/i386/kernel/setup.c
 * and originally developed by Andy Grover <andrew.grover@intel.com>
 */

#include <stdio.h>
#include <string.h>
#include <lrmi.h>

int main (void)
{
	struct LRMI_regs	r;
	int			retval;

	if (!LRMI_init())
		return 0;

	memset(&r, 0, sizeof(r));

	r.eax = 0x0000E980;
	r.edx = 0x47534943;

	retval = LRMI_int(0x15, &r);

	if (!retval) {
		printf("Failed!\n");
		return 0;
	}
	if (r.eax == 0x47534943) {
		printf("BIOS supports GSIC call:\n");
		printf("\tsignature: %c%c%c%c\n",
		       (r.eax >> 24) & 0xff,
		       (r.eax >> 16) & 0xff,
		       (r.eax >> 8) & 0xff,
		       (r.eax) & 0xff);
		printf("\tcommand port = 0x%.4x\n",
		       r.ebx & 0xffff);
		printf("\tcommand =      0x%.4x\n",
		       (r.ebx >> 16) & 0xffff);
		printf("\tevent port =   0x%.8x\n", r.ecx);
		printf("\tflags =        0x%.8x\n", r.edx);
		if (((r.ebx >> 16) & 0xffff) != 0x82) {
			printf("non-default command value. If speedstep-smi "
			       "doesn't work out of the box,\nyou may want to "
			       "try out the default value by passing "
			       "smi_cmd=0x82 to the module\n ON YOUR OWN "
			       "RISK.\n");
		}
		if ((r.ebx & 0xffff) != 0xb2) {
			printf("non-default command port. If speedstep-smi "
			       "doesn't work out of the box,\nyou may want to "
			       "try out the default value by passing "
			       "smi_port=0x82 to the module\n ON YOUR OWN "
			       "RISK.\n");
		}
	} else {
		printf("BIOS DOES NOT support GSIC call.  Dumping registers anyway:\n");
		printf("eax = 0x%.8x\n", r.eax);
		printf("ebx = 0x%.8x\n", r.ebx);
		printf("ecx = 0x%.8x\n", r.ecx);
		printf("edx = 0x%.8x\n", r.edx);
		printf("Note also that some BIOS do not support the initial "
		       "GSIC call, but the newer\nspeedstep-smi driver may "
		       "work.\nFor this, you need to pass some arguments to "
		       "the speedstep-smi driver:\n");
		printf("\tsmi_cmd=0x?? smi_port=0x?? smi_sig=1\n");
		printf("\nUnfortunately, you have to know what exactly are "
		       "smi_cmd and smi_port, and this\nis system "
		       "dependent.\n");
	}
	return 1;
}