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