110 lines
2.6 KiB
C
110 lines
2.6 KiB
C
#include <linux/module.h>
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#include <linux/smp.h>
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#include <linux/time.h>
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#include <linux/errno.h>
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#include <asm/io.h>
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/* IBM Summit (EXA) Cyclone counter code*/
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#define CYCLONE_CBAR_ADDR 0xFEB00CD0
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#define CYCLONE_PMCC_OFFSET 0x51A0
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#define CYCLONE_MPMC_OFFSET 0x51D0
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#define CYCLONE_MPCS_OFFSET 0x51A8
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#define CYCLONE_TIMER_FREQ 100000000
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int use_cyclone;
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void __init cyclone_setup(void)
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{
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use_cyclone = 1;
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}
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struct time_interpolator cyclone_interpolator = {
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.source = TIME_SOURCE_MMIO64,
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.shift = 16,
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.frequency = CYCLONE_TIMER_FREQ,
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.drift = -100,
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.mask = (1LL << 40) - 1
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};
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int __init init_cyclone_clock(void)
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{
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u64* reg;
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u64 base; /* saved cyclone base address */
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u64 offset; /* offset from pageaddr to cyclone_timer register */
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int i;
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u32* volatile cyclone_timer; /* Cyclone MPMC0 register */
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if (!use_cyclone)
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return -ENODEV;
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printk(KERN_INFO "Summit chipset: Starting Cyclone Counter.\n");
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/* find base address */
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offset = (CYCLONE_CBAR_ADDR);
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reg = (u64*)ioremap_nocache(offset, sizeof(u64));
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if(!reg){
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printk(KERN_ERR "Summit chipset: Could not find valid CBAR register.\n");
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use_cyclone = 0;
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return -ENODEV;
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}
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base = readq(reg);
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if(!base){
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printk(KERN_ERR "Summit chipset: Could not find valid CBAR value.\n");
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use_cyclone = 0;
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return -ENODEV;
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}
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iounmap(reg);
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/* setup PMCC */
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offset = (base + CYCLONE_PMCC_OFFSET);
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reg = (u64*)ioremap_nocache(offset, sizeof(u64));
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if(!reg){
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printk(KERN_ERR "Summit chipset: Could not find valid PMCC register.\n");
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use_cyclone = 0;
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return -ENODEV;
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}
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writel(0x00000001,reg);
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iounmap(reg);
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/* setup MPCS */
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offset = (base + CYCLONE_MPCS_OFFSET);
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reg = (u64*)ioremap_nocache(offset, sizeof(u64));
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if(!reg){
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printk(KERN_ERR "Summit chipset: Could not find valid MPCS register.\n");
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use_cyclone = 0;
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return -ENODEV;
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}
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writel(0x00000001,reg);
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iounmap(reg);
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/* map in cyclone_timer */
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offset = (base + CYCLONE_MPMC_OFFSET);
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cyclone_timer = (u32*)ioremap_nocache(offset, sizeof(u32));
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if(!cyclone_timer){
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printk(KERN_ERR "Summit chipset: Could not find valid MPMC register.\n");
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use_cyclone = 0;
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return -ENODEV;
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}
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/*quick test to make sure its ticking*/
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for(i=0; i<3; i++){
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u32 old = readl(cyclone_timer);
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int stall = 100;
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while(stall--) barrier();
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if(readl(cyclone_timer) == old){
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printk(KERN_ERR "Summit chipset: Counter not counting! DISABLED\n");
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iounmap(cyclone_timer);
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cyclone_timer = 0;
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use_cyclone = 0;
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return -ENODEV;
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}
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}
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/* initialize last tick */
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cyclone_interpolator.addr = cyclone_timer;
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register_time_interpolator(&cyclone_interpolator);
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return 0;
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}
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__initcall(init_cyclone_clock);
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