1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * EISA specific code
4 */
5#include <linux/ioport.h>
6#include <linux/eisa.h>
7#include <linux/io.h>
8
9#include <xen/xen.h>
10
11static __init int eisa_bus_probe(void)
12{
13 void __iomem *p;
14
15 if (xen_pv_domain() && !xen_initial_domain())
16 return 0;
17
18 p = ioremap(offset: 0x0FFFD9, size: 4);
19 if (p && readl(addr: p) == 'E' + ('I' << 8) + ('S' << 16) + ('A' << 24))
20 EISA_bus = 1;
21 iounmap(addr: p);
22 return 0;
23}
24subsys_initcall(eisa_bus_probe);
25

source code of linux/arch/x86/kernel/eisa.c