diff options
Diffstat (limited to 'libdde_linux26/lib/src/arch')
| -rw-r--r-- | libdde_linux26/lib/src/arch/l4/timer.c | 19 | ||||
| -rw-r--r-- | libdde_linux26/lib/src/arch/x86/lib/delay.c | 138 |
2 files changed, 138 insertions, 19 deletions
diff --git a/libdde_linux26/lib/src/arch/l4/timer.c b/libdde_linux26/lib/src/arch/l4/timer.c index 2b657ab4..b85c83a9 100644 --- a/libdde_linux26/lib/src/arch/l4/timer.c +++ b/libdde_linux26/lib/src/arch/l4/timer.c @@ -126,25 +126,6 @@ void msleep(unsigned int msecs) ddekit_thread_msleep(msecs); } - -void __const_udelay(unsigned long xloops) -{ - ddekit_thread_usleep(xloops); -} - - -void __udelay(unsigned long usecs) -{ - ddekit_thread_usleep(usecs); -} - - -void __ndelay(unsigned long nsecs) -{ - ddekit_thread_nsleep(nsecs); -} - - void __init l4dde26_init_timers(void) { ddekit_init_timers(); diff --git a/libdde_linux26/lib/src/arch/x86/lib/delay.c b/libdde_linux26/lib/src/arch/x86/lib/delay.c new file mode 100644 index 00000000..6097c6bb --- /dev/null +++ b/libdde_linux26/lib/src/arch/x86/lib/delay.c @@ -0,0 +1,138 @@ +/* + * Precise Delay Loops for i386 + * + * Copyright (C) 1993 Linus Torvalds + * Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz> + * Copyright (C) 2008 Jiri Hladky <hladky _dot_ jiri _at_ gmail _dot_ com> + * + * The __delay function must _NOT_ be inlined as its execution time + * depends wildly on alignment on many x86 processors. The additional + * jump magic is needed to get the timing stable on all the CPU's + * we have to worry about. + */ + +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/timex.h> +#include <linux/preempt.h> +#include <linux/delay.h> +#include <linux/init.h> + +#include <asm/processor.h> +#include <asm/delay.h> +#include <asm/timer.h> + +#ifdef CONFIG_SMP +# include <asm/smp.h> +#endif +#include <ddekit/timer.h> + +/* simple loop based delay: */ +static void delay_loop(unsigned long loops) +{ + asm volatile( + " test %0,%0 \n" + " jz 3f \n" + " jmp 1f \n" + + ".align 16 \n" + "1: jmp 2f \n" + + ".align 16 \n" + "2: dec %0 \n" + " jnz 2b \n" + "3: dec %0 \n" + + : /* we don't need output */ + :"a" (loops) + ); +} + +/* TSC based delay: */ +static void delay_tsc(unsigned long loops) +{ + unsigned long bclock, now; + int cpu; + + preempt_disable(); + cpu = smp_processor_id(); + rdtscl(bclock); + for (;;) { + rdtscl(now); + if ((now - bclock) >= loops) + break; + + /* Allow RT tasks to run */ + preempt_enable(); + rep_nop(); + preempt_disable(); + + /* + * It is possible that we moved to another CPU, and + * since TSC's are per-cpu we need to calculate + * that. The delay must guarantee that we wait "at + * least" the amount of time. Being moved to another + * CPU could make the wait longer but we just need to + * make sure we waited long enough. Rebalance the + * counter for this CPU. + */ + if (unlikely(cpu != smp_processor_id())) { + loops -= (now - bclock); + cpu = smp_processor_id(); + rdtscl(bclock); + } + } + preempt_enable(); +} + +/* + * Since we calibrate only once at boot, this + * function should be set once at boot and not changed + */ +static void (*delay_fn)(unsigned long) = delay_loop; + +void use_tsc_delay(void) +{ + delay_fn = delay_tsc; +} + +int __devinit read_current_timer(unsigned long *timer_val) +{ + if (delay_fn == delay_tsc) { + rdtscll(*timer_val); + return 0; + } + return -1; +} + +void __delay(unsigned long loops) +{ + delay_fn(loops); +} +EXPORT_SYMBOL(__delay); + +inline void __const_udelay(unsigned long xloops) +{ + int d0; + + xloops *= 4; + asm("mull %%edx" + :"=d" (xloops), "=&a" (d0) + :"1" (xloops), "0" + (loops_per_jiffy * (HZ/4))); + + __delay(++xloops); +} +EXPORT_SYMBOL(__const_udelay); + +void __udelay(unsigned long usecs) +{ + __const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */ +} +EXPORT_SYMBOL(__udelay); + +void __ndelay(unsigned long nsecs) +{ + __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */ +} +EXPORT_SYMBOL(__ndelay); |