2 * ----------------------------------------------------------------------------
3 * "THE BEER-WARE LICENSE" (Revision 42):
4 * <phk@FreeBSD.org> wrote this file. As long as you retain this notice you
5 * can do whatever you want with this stuff. If we meet some day, and you think
6 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
7 * ----------------------------------------------------------------------------
9 * $FreeBSD: src/sys/i386/i386/elan-mmcr.c,v 1.6.2.1 2002/09/17 22:39:53 sam Exp $
10 * The AMD Elan sc520 is a system-on-chip gadget which is used in embedded
11 * kind of things, see www.soekris.com for instance, and it has a few quirks
12 * we need to deal with.
13 * Unfortunately we cannot identify the gadget by CPUID output because it
14 * depends on strapping options and only the stepping field may be useful
15 * and those are undocumented from AMDs side.
17 * So instead we recognize the on-chip host-PCI bridge and call back from
18 * sys/i386/pci/pci_bus.c to here if we find it.
21 #include <sys/param.h>
22 #include <sys/systm.h>
23 #include <sys/kernel.h>
25 #include <sys/device.h>
27 #include <sys/sysctl.h>
30 #include <machine/md_var.h>
40 elan_get_timecount(struct timecounter *tc)
42 return (elan_mmcr[0xc84 / 2]);
45 static struct timecounter elan_timecounter = {
56 init_AMD_Elan_sc520(void)
62 kprintf("Doing h0h0magic for AMD Elan sc520\n");
63 elan_mmcr = pmap_mapdev(0xfffef000, 0x1000);
66 * The i8254 is driven with a nonstandard frequency which is
68 * f = 32768 * 45 * 25 / 31 = 1189161.29...
69 * We use the sysctl to get the timecounter etc into whack.
73 i = kernel_sysctlbyname("machdep.i8254_freq",
78 kprintf("sysctl machdep.i8254_freq=%d returns %d\n", new, i);
81 /* Start GP timer #2 and use it as timecounter, hz permitting */
82 elan_mmcr[0xc82 / 2] = 0xc001;
83 init_timecounter(&elan_timecounter);
89 * Device driver initialization stuff
92 static d_open_t elan_open;
93 static d_close_t elan_close;
94 static d_ioctl_t elan_ioctl;
95 static d_mmap_t elan_mmap;
97 #define CDEV_MAJOR 100
98 static struct dev_ops elan_ops = {
101 .d_close = elan_close,
102 .d_ioctl = elan_ioctl,
107 elan_open(struct dev_open_args *ap)
113 elan_close(struct dev_close_args *ap)
119 elan_mmap(struct dev_mmap_args *ap)
121 if (ap->a_offset >= 0x1000)
123 ap->a_result = i386_btop(0xfffef000);
128 elan_ioctl(struct dev_ioctl_args *ap)
137 if (elan_mmcr == NULL)
139 kprintf("Elan-mmcr driver: MMCR at %p\n", elan_mmcr);
140 make_dev(&elan_ops, 0, UID_ROOT, GID_WHEEL, 0600, "elan-mmcr");
143 SYSINIT(elan, SI_SUB_PSEUDO, SI_ORDER_MIDDLE+CDEV_MAJOR,elan_drvinit,NULL);