/arch/ia64/kernel/cyclone.c

  1#include <linux/module.h>
  2#include <linux/smp.h>
  3#include <linux/time.h>
  4#include <linux/errno.h>
  5#include <asm/io.h>
  6
  7/* IBM Summit (EXA) Cyclone counter code*/
  8#define CYCLONE_CBAR_ADDR 0xFEB00CD0
  9#define CYCLONE_PMCC_OFFSET 0x51A0
 10#define CYCLONE_MPMC_OFFSET 0x51D0
 11#define CYCLONE_MPCS_OFFSET 0x51A8
 12#define CYCLONE_TIMER_FREQ 100000000
 13
 14int use_cyclone;
 15void __init cyclone_setup(void)
 16{
 17	use_cyclone = 1;
 18}
 19
 20
 21struct time_interpolator cyclone_interpolator = {
 22	.source =	TIME_SOURCE_MMIO64,
 23	.shift =	16,
 24	.frequency =	CYCLONE_TIMER_FREQ,
 25	.drift =	-100,
 26	.mask =		(1LL << 40) - 1
 27};
 28
 29int __init init_cyclone_clock(void)
 30{
 31	u64* reg;
 32	u64 base;	/* saved cyclone base address */
 33	u64 offset;	/* offset from pageaddr to cyclone_timer register */
 34	int i;
 35	u32* volatile cyclone_timer;	/* Cyclone MPMC0 register */
 36
 37	if (!use_cyclone)
 38		return -ENODEV;
 39
 40	printk(KERN_INFO "Summit chipset: Starting Cyclone Counter.\n");
 41
 42	/* find base address */
 43	offset = (CYCLONE_CBAR_ADDR);
 44	reg = (u64*)ioremap_nocache(offset, sizeof(u64));
 45	if(!reg){
 46		printk(KERN_ERR "Summit chipset: Could not find valid CBAR register.\n");
 47		use_cyclone = 0;
 48		return -ENODEV;
 49	}
 50	base = readq(reg);
 51	if(!base){
 52		printk(KERN_ERR "Summit chipset: Could not find valid CBAR value.\n");
 53		use_cyclone = 0;
 54		return -ENODEV;
 55	}
 56	iounmap(reg);
 57
 58	/* setup PMCC */
 59	offset = (base + CYCLONE_PMCC_OFFSET);
 60	reg = (u64*)ioremap_nocache(offset, sizeof(u64));
 61	if(!reg){
 62		printk(KERN_ERR "Summit chipset: Could not find valid PMCC register.\n");
 63		use_cyclone = 0;
 64		return -ENODEV;
 65	}
 66	writel(0x00000001,reg);
 67	iounmap(reg);
 68
 69	/* setup MPCS */
 70	offset = (base + CYCLONE_MPCS_OFFSET);
 71	reg = (u64*)ioremap_nocache(offset, sizeof(u64));
 72	if(!reg){
 73		printk(KERN_ERR "Summit chipset: Could not find valid MPCS register.\n");
 74		use_cyclone = 0;
 75		return -ENODEV;
 76	}
 77	writel(0x00000001,reg);
 78	iounmap(reg);
 79
 80	/* map in cyclone_timer */
 81	offset = (base + CYCLONE_MPMC_OFFSET);
 82	cyclone_timer = (u32*)ioremap_nocache(offset, sizeof(u32));
 83	if(!cyclone_timer){
 84		printk(KERN_ERR "Summit chipset: Could not find valid MPMC register.\n");
 85		use_cyclone = 0;
 86		return -ENODEV;
 87	}
 88
 89	/*quick test to make sure its ticking*/
 90	for(i=0; i<3; i++){
 91		u32 old = readl(cyclone_timer);
 92		int stall = 100;
 93		while(stall--) barrier();
 94		if(readl(cyclone_timer) == old){
 95			printk(KERN_ERR "Summit chipset: Counter not counting! DISABLED\n");
 96			iounmap(cyclone_timer);
 97			cyclone_timer = 0;
 98			use_cyclone = 0;
 99			return -ENODEV;
100		}
101	}
102	/* initialize last tick */
103	cyclone_interpolator.addr = cyclone_timer;
104	register_time_interpolator(&cyclone_interpolator);
105
106	return 0;
107}
108
109__initcall(init_cyclone_clock);