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 <linux/clocksource.h>
   7 #include <asm/io.h>
   8
   9 /* IBM Summit (EXA) Cyclone counter code*/
  10 #define CYCLONE_CBAR_ADDR 0xFEB00CD0
  11 #define CYCLONE_PMCC_OFFSET 0x51A0
  12 #define CYCLONE_MPMC_OFFSET 0x51D0
  13 #define CYCLONE_MPCS_OFFSET 0x51A8
  14 #define CYCLONE_TIMER_FREQ 100000000
  15
  16 int use_cyclone;
  17 void __init cyclone_setup(void)
  18 {
  19         use_cyclone = 1;
  20 }
  21
  22 static void __iomem *cyclone_mc;
  23
  24 static cycle_t read_cyclone(struct clocksource *cs)
  25 {
  26         return (cycle_t)readq((void __iomem *)cyclone_mc);
  27 }
  28
  29 static struct clocksource clocksource_cyclone = {
  30         .name           = "cyclone",
  31         .rating         = 300,
  32         .read           = read_cyclone,
  33         .mask           = (1LL << 40) - 1,
  34         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  35 };
  36
  37 int __init init_cyclone_clock(void)
  38 {
  39         u64 __iomem *reg;
  40         u64 base;       /* saved cyclone base address */
  41         u64 offset;     /* offset from pageaddr to cyclone_timer register */
  42         int i;
  43         u32 __iomem *cyclone_timer;     /* Cyclone MPMC0 register */
  44
  45         if (!use_cyclone)
  46                 return 0;
  47
  48         printk(KERN_INFO "Summit chipset: Starting Cyclone Counter.\n");
  49
  50         /* find base address */
  51         offset = (CYCLONE_CBAR_ADDR);
  52         reg = ioremap_nocache(offset, sizeof(u64));
  53         if(!reg){
  54                 printk(KERN_ERR "Summit chipset: Could not find valid CBAR"
  55                                 " register.\n");
  56                 use_cyclone = 0;
  57                 return -ENODEV;
  58         }
  59         base = readq(reg);
  60         iounmap(reg);
  61         if(!base){
  62                 printk(KERN_ERR "Summit chipset: Could not find valid CBAR"
  63                                 " value.\n");
  64                 use_cyclone = 0;
  65                 return -ENODEV;
  66         }
  67
  68         /* setup PMCC */
  69         offset = (base + CYCLONE_PMCC_OFFSET);
  70         reg = ioremap_nocache(offset, sizeof(u64));
  71         if(!reg){
  72                 printk(KERN_ERR "Summit chipset: Could not find valid PMCC"
  73                                 " register.\n");
  74                 use_cyclone = 0;
  75                 return -ENODEV;
  76         }
  77         writel(0x00000001,reg);
  78         iounmap(reg);
  79
  80         /* setup MPCS */
  81         offset = (base + CYCLONE_MPCS_OFFSET);
  82         reg = ioremap_nocache(offset, sizeof(u64));
  83         if(!reg){
  84                 printk(KERN_ERR "Summit chipset: Could not find valid MPCS"
  85                                 " register.\n");
  86                 use_cyclone = 0;
  87                 return -ENODEV;
  88         }
  89         writel(0x00000001,reg);
  90         iounmap(reg);
  91
  92         /* map in cyclone_timer */
  93         offset = (base + CYCLONE_MPMC_OFFSET);
  94         cyclone_timer = ioremap_nocache(offset, sizeof(u32));
  95         if(!cyclone_timer){
  96                 printk(KERN_ERR "Summit chipset: Could not find valid MPMC"
  97                                 " register.\n");
  98                 use_cyclone = 0;
  99                 return -ENODEV;
 100         }
 101
 102         /*quick test to make sure its ticking*/
 103         for(i=0; i<3; i++){
 104                 u32 old = readl(cyclone_timer);
 105                 int stall = 100;
 106                 while(stall--) barrier();
 107                 if(readl(cyclone_timer) == old){
 108                         printk(KERN_ERR "Summit chipset: Counter not counting!"
 109                                         " DISABLED\n");
 110                         iounmap(cyclone_timer);
 111                         cyclone_timer = NULL;
 112                         use_cyclone = 0;
 113                         return -ENODEV;
 114                 }
 115         }
 116         /* initialize last tick */
 117         cyclone_mc = cyclone_timer;
 118         clocksource_cyclone.archdata.fsys_mmio = cyclone_timer;
 119         clocksource_register_hz(&clocksource_cyclone, CYCLONE_TIMER_FREQ);
 120
 121         return 0;
 122 }
 123
 124 __initcall(init_cyclone_clock);