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#include <linux/module.h>
#include <linux/smp.h>
#include <linux/time.h>
#include <linux/errno.h>
#include <linux/timex.h>
#include <linux/clocksource.h>
#include <asm/io.h>
/* IBM Summit (EXA) Cyclone counter code*/
#define CYCLONE_CBAR_ADDR 0xFEB00CD0
#define CYCLONE_PMCC_OFFSET 0x51A0
#define CYCLONE_MPMC_OFFSET 0x51D0
#define CYCLONE_MPCS_OFFSET 0x51A8
#define CYCLONE_TIMER_FREQ 100000000
int use_cyclone;
void __init cyclone_setup(void)
{
use_cyclone = 1;
}
static void __iomem *cyclone_mc;
static cycle_t read_cyclone(void)
{
return (cycle_t)readq((void __iomem *)cyclone_mc);
}
static struct clocksource clocksource_cyclone = {
.name = "cyclone",
.rating = 300,
.read = read_cyclone,
.mask = (1LL << 40) - 1,
.mult = 0, /*to be caluclated*/
.shift = 16,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
int __init init_cyclone_clock(void)
{
u64* reg;
u64 base; /* saved cyclone base address */
u64 offset; /* offset from pageaddr to cyclone_timer register */
int i;
u32* volatile cyclone_timer; /* Cyclone MPMC0 register */
if (!use_cyclone)
return 0;
printk(KERN_INFO "Summit chipset: Starting Cyclone Counter.\n");
/* find base address */
offset = (CYCLONE_CBAR_ADDR);
reg = (u64*)ioremap_nocache(offset, sizeof(u64));
if(!reg){
printk(KERN_ERR "Summit chipset: Could not find valid CBAR"
" register.\n");
use_cyclone = 0;
return -ENODEV;
}
base = readq(reg);
if(!base){
printk(KERN_ERR "Summit chipset: Could not find valid CBAR"
" value.\n");
use_cyclone = 0;
return -ENODEV;
}
iounmap(reg);
/* setup PMCC */
offset = (base + CYCLONE_PMCC_OFFSET);
reg = (u64*)ioremap_nocache(offset, sizeof(u64));
if(!reg){
printk(KERN_ERR "Summit chipset: Could not find valid PMCC"
" register.\n");
use_cyclone = 0;
return -ENODEV;
}
writel(0x00000001,reg);
iounmap(reg);
/* setup MPCS */
offset = (base + CYCLONE_MPCS_OFFSET);
reg = (u64*)ioremap_nocache(offset, sizeof(u64));
if(!reg){
printk(KERN_ERR "Summit chipset: Could not find valid MPCS"
" register.\n");
use_cyclone = 0;
return -ENODEV;
}
writel(0x00000001,reg);
iounmap(reg);
/* map in cyclone_timer */
offset = (base + CYCLONE_MPMC_OFFSET);
cyclone_timer = (u32*)ioremap_nocache(offset, sizeof(u32));
if(!cyclone_timer){
printk(KERN_ERR "Summit chipset: Could not find valid MPMC"
" register.\n");
use_cyclone = 0;
return -ENODEV;
}
/*quick test to make sure its ticking*/
for(i=0; i<3; i++){
u32 old = readl(cyclone_timer);
int stall = 100;
while(stall--) barrier();
if(readl(cyclone_timer) == old){
printk(KERN_ERR "Summit chipset: Counter not counting!"
" DISABLED\n");
iounmap(cyclone_timer);
cyclone_timer = 0;
use_cyclone = 0;
return -ENODEV;
}
}
/* initialize last tick */
cyclone_mc = cyclone_timer;
clocksource_cyclone.fsys_mmio = cyclone_timer;
clocksource_cyclone.mult = clocksource_hz2mult(CYCLONE_TIMER_FREQ,
clocksource_cyclone.shift);
clocksource_register(&clocksource_cyclone);
return 0;
}
__initcall(init_cyclone_clock);
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