Initial import from FreeBSD RELENG_4:
[dragonfly.git] / sys / i386 / i386 / elan-mmcr.c
CommitLineData
984263bc
MD
1/*
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 * ----------------------------------------------------------------------------
8 *
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.
16 *
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.
19 */
20
21#include <sys/param.h>
22#include <sys/systm.h>
23#include <sys/kernel.h>
24#include <sys/conf.h>
25#include <sys/proc.h>
26#include <sys/sysctl.h>
27#include <sys/time.h>
28
29#include <machine/md_var.h>
30
31#include <vm/vm.h>
32#include <vm/pmap.h>
33
34uint16_t *elan_mmcr;
35
36
37static unsigned
38elan_get_timecount(struct timecounter *tc)
39{
40 return (elan_mmcr[0xc84 / 2]);
41}
42
43static struct timecounter elan_timecounter = {
44 elan_get_timecount,
45 0,
46 0xffff,
47 33333333 / 4,
48 "ELAN"
49};
50
51void
52init_AMD_Elan_sc520(void)
53{
54 u_int new;
55 int i;
56
57 if (bootverbose)
58 printf("Doing h0h0magic for AMD Elan sc520\n");
59 elan_mmcr = pmap_mapdev(0xfffef000, 0x1000);
60
61 /*-
62 * The i8254 is driven with a nonstandard frequency which is
63 * derived thusly:
64 * f = 32768 * 45 * 25 / 31 = 1189161.29...
65 * We use the sysctl to get the timecounter etc into whack.
66 */
67
68 new = 1189161;
69 i = kernel_sysctlbyname(curproc, "machdep.i8254_freq",
70 NULL, 0,
71 &new, sizeof new,
72 NULL);
73 if (bootverbose)
74 printf("sysctl machdep.i8254_freq=%d returns %d\n", new, i);
75
76 /* Start GP timer #2 and use it as timecounter, hz permitting */
77 elan_mmcr[0xc82 / 2] = 0xc001;
78 init_timecounter(&elan_timecounter);
79}
80
81
82/*
83 * Device driver initialization stuff
84 */
85
86static d_open_t elan_open;
87static d_close_t elan_close;
88static d_ioctl_t elan_ioctl;
89static d_mmap_t elan_mmap;
90
91#define CDEV_MAJOR 100 /* Share with xrpu */
92static struct cdevsw elan_cdevsw = {
93 /* open */ elan_open,
94 /* close */ elan_close,
95 /* read */ noread,
96 /* write */ nowrite,
97 /* ioctl */ elan_ioctl,
98 /* poll */ nopoll,
99 /* mmap */ elan_mmap,
100 /* strategy */ nostrategy,
101 /* name */ "elan",
102 /* maj */ CDEV_MAJOR,
103 /* dump */ nodump,
104 /* psize */ nopsize,
105 /* flags */ 0,
106};
107
108static int
109elan_open(dev_t dev, int flag, int mode, struct proc *p)
110{
111 return (0);
112}
113
114static int
115elan_close(dev_t dev, int flag, int mode, struct proc *p)
116{
117 return (0);
118}
119
120static int
121elan_mmap(dev_t dev, vm_offset_t offset, int nprot)
122{
123 if (offset >= 0x1000)
124 return (-1);
125 return (i386_btop(0xfffef000));
126}
127
128static int
129elan_ioctl(dev_t dev, u_long cmd, caddr_t arg, int flag, struct proc *p)
130{
131 return(ENOENT);
132}
133
134static void
135elan_drvinit(void)
136{
137
138 if (elan_mmcr == NULL)
139 return;
140 printf("Elan-mmcr driver: MMCR at %p\n", elan_mmcr);
141 make_dev(&elan_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "elan-mmcr");
142 return;
143}
144
145SYSINIT(elan, SI_SUB_PSEUDO, SI_ORDER_MIDDLE+CDEV_MAJOR,elan_drvinit,NULL);