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#include <linux/clocksource.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/timex.h>
#include <linux/init.h>
#include <asm/pgtable.h>
#include <asm/io.h>
#include <asm/mach_timer.h>
#define CYCLONE_CBAR_ADDR 0xFEB00CD0 /* base address ptr */
#define CYCLONE_PMCC_OFFSET 0x51A0 /* offset to control register */
#define CYCLONE_MPCS_OFFSET 0x51A8 /* offset to select register */
#define CYCLONE_MPMC_OFFSET 0x51D0 /* offset to count register */
#define CYCLONE_TIMER_FREQ 99780000 /* 100Mhz, but not really */
#define CYCLONE_TIMER_MASK CLOCKSOURCE_MASK(32) /* 32 bit mask */
int use_cyclone = 0;
static void __iomem *cyclone_ptr;
static cycle_t read_cyclone(struct clocksource *cs)
{
return (cycle_t)readl(cyclone_ptr);
}
static struct clocksource clocksource_cyclone = {
.name = "cyclone",
.rating = 250,
.read = read_cyclone,
.mask = CYCLONE_TIMER_MASK,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static int __init init_cyclone_clocksource(void)
{
unsigned long base; /* saved value from CBAR */
unsigned long offset;
u32 __iomem* volatile cyclone_timer; /* Cyclone MPMC0 register */
u32 __iomem* reg;
int i;
/* make sure we're on a summit box: */
if (!use_cyclone)
return -ENODEV;
printk(KERN_INFO "Summit chipset: Starting Cyclone Counter.\n");
/* find base address: */
offset = CYCLONE_CBAR_ADDR;
reg = ioremap_nocache(offset, sizeof(reg));
if (!reg) {
printk(KERN_ERR "Summit chipset: Could not find valid CBAR register.\n");
return -ENODEV;
}
/* even on 64bit systems, this is only 32bits: */
base = readl(reg);
if (!base) {
printk(KERN_ERR "Summit chipset: Could not find valid CBAR value.\n");
return -ENODEV;
}
iounmap(reg);
/* setup PMCC: */
offset = base + CYCLONE_PMCC_OFFSET;
reg = ioremap_nocache(offset, sizeof(reg));
if (!reg) {
printk(KERN_ERR "Summit chipset: Could not find valid PMCC register.\n");
return -ENODEV;
}
writel(0x00000001,reg);
iounmap(reg);
/* setup MPCS: */
offset = base + CYCLONE_MPCS_OFFSET;
reg = ioremap_nocache(offset, sizeof(reg));
if (!reg) {
printk(KERN_ERR "Summit chipset: Could not find valid MPCS register.\n");
return -ENODEV;
}
writel(0x00000001,reg);
iounmap(reg);
/* map in cyclone_timer: */
offset = base + CYCLONE_MPMC_OFFSET;
cyclone_timer = ioremap_nocache(offset, sizeof(u64));
if (!cyclone_timer) {
printk(KERN_ERR "Summit chipset: Could not find valid MPMC register.\n");
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 = NULL;
return -ENODEV;
}
}
cyclone_ptr = cyclone_timer;
return clocksource_register_hz(&clocksource_cyclone,
CYCLONE_TIMER_FREQ);
}
arch_initcall(init_cyclone_clocksource);
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