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 * $DragonFly: src/sys/i386/i386/Attic/elan-mmcr.c,v 1.6 2004/05/13 23:49:23 dillon Exp $
11 * The AMD Elan sc520 is a system-on-chip gadget which is used in embedded
12 * kind of things, see www.soekris.com for instance, and it has a few quirks
13 * we need to deal with.
14 * Unfortunately we cannot identify the gadget by CPUID output because it
15 * depends on strapping options and only the stepping field may be useful
16 * and those are undocumented from AMDs side.
18 * So instead we recognize the on-chip host-PCI bridge and call back from
19 * sys/i386/pci/pci_bus.c to here if we find it.
22 #include <sys/param.h>
23 #include <sys/systm.h>
24 #include <sys/kernel.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 printf("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 printf("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 /* Share with xrpu */
98 static struct cdevsw elan_cdevsw = {
100 /* maj */ CDEV_MAJOR,
105 /* open */ elan_open,
106 /* close */ elan_close,
109 /* ioctl */ elan_ioctl,
111 /* mmap */ elan_mmap,
112 /* strategy */ nostrategy,
118 elan_open(dev_t dev, int flag, int mode, struct thread *td)
124 elan_close(dev_t dev, int flag, int mode, struct thread *td)
130 elan_mmap(dev_t dev, vm_offset_t offset, int nprot)
132 if (offset >= 0x1000)
134 return (i386_btop(0xfffef000));
138 elan_ioctl(dev_t dev, u_long cmd, caddr_t arg, int flag, struct thread *td)
147 if (elan_mmcr == NULL)
149 printf("Elan-mmcr driver: MMCR at %p\n", elan_mmcr);
150 make_dev(&elan_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "elan-mmcr");
154 SYSINIT(elan, SI_SUB_PSEUDO, SI_ORDER_MIDDLE+CDEV_MAJOR,elan_drvinit,NULL);