diff options
| -rw-r--r-- | libdde_linux26/lib/src/Makefile | 2 | ||||
| -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 | ||||
| -rw-r--r-- | libdde_linux26/lib/src/init/calibrate.c | 182 |
4 files changed, 322 insertions, 19 deletions
diff --git a/libdde_linux26/lib/src/Makefile b/libdde_linux26/lib/src/Makefile index ed53fdeb..358196bb 100644 --- a/libdde_linux26/lib/src/Makefile +++ b/libdde_linux26/lib/src/Makefile @@ -58,6 +58,7 @@ SRC_C_libdde_linux26.o.a = $(addprefix arch/l4/, $(SRC_DDE)) ifeq ($(ARCH), x86) SRC_S_libdde_linux26.o.a += $(ARCH_DIR)/lib/semaphore_32.S +SRC_S_libdde_linux26.o.a += $(ARCH_DIR)/lib/delay.o SRC_C_libdde_linux26.o.a += lib/rwsem.c SRC_C_libdde_linux26.o.a += $(ARCH_DIR)/kernel/pci-dma.c SRC_C_libdde_linux26.o.a += $(ARCH_DIR)/kernel/pci-nommu.c @@ -120,6 +121,7 @@ SRC_C_libdde_linux26.o.a += \ lib/string.c \ lib/vsprintf.c \ lib/rbtree.c \ + init/calibrate.c \ mm/dmapool.c \ mm/mempool.c \ mm/swap.c \ 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); diff --git a/libdde_linux26/lib/src/init/calibrate.c b/libdde_linux26/lib/src/init/calibrate.c new file mode 100644 index 00000000..aede8e53 --- /dev/null +++ b/libdde_linux26/lib/src/init/calibrate.c @@ -0,0 +1,182 @@ +/* calibrate.c: default delay calibration + * + * Excised from init/main.c + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +#include <linux/jiffies.h> +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/timex.h> +#include <linux/smp.h> +#include <ddekit/timer.h> + +unsigned long loops_per_jiffy = (1<<12); +EXPORT_SYMBOL(loops_per_jiffy); + +unsigned long lpj_fine; +unsigned long preset_lpj; +static int __init lpj_setup(char *str) +{ + preset_lpj = simple_strtoul(str,NULL,0); + return 1; +} + +__setup("lpj=", lpj_setup); + +#ifdef ARCH_HAS_READ_CURRENT_TIMER + +/* This routine uses the read_current_timer() routine and gets the + * loops per jiffy directly, instead of guessing it using delay(). + * Also, this code tries to handle non-maskable asynchronous events + * (like SMIs) + */ +#define DELAY_CALIBRATION_TICKS ((HZ < 100) ? 1 : (HZ/100)) +#define MAX_DIRECT_CALIBRATION_RETRIES 5 + +static unsigned long __cpuinit calibrate_delay_direct(void) +{ + unsigned long pre_start, start, post_start; + unsigned long pre_end, end, post_end; + unsigned long start_jiffies; + unsigned long timer_rate_min, timer_rate_max; + unsigned long good_timer_sum = 0; + unsigned long good_timer_count = 0; + int i; + + if (read_current_timer(&pre_start) < 0 ) + return 0; + + /* + * A simple loop like + * while ( jiffies < start_jiffies+1) + * start = read_current_timer(); + * will not do. As we don't really know whether jiffy switch + * happened first or timer_value was read first. And some asynchronous + * event can happen between these two events introducing errors in lpj. + * + * So, we do + * 1. pre_start <- When we are sure that jiffy switch hasn't happened + * 2. check jiffy switch + * 3. start <- timer value before or after jiffy switch + * 4. post_start <- When we are sure that jiffy switch has happened + * + * Note, we don't know anything about order of 2 and 3. + * Now, by looking at post_start and pre_start difference, we can + * check whether any asynchronous event happened or not + */ + + for (i = 0; i < MAX_DIRECT_CALIBRATION_RETRIES; i++) { + pre_start = 0; + read_current_timer(&start); + start_jiffies = jiffies; + while (jiffies <= (start_jiffies + 1)) { + pre_start = start; + read_current_timer(&start); + } + read_current_timer(&post_start); + + pre_end = 0; + end = post_start; + while (jiffies <= + (start_jiffies + 1 + DELAY_CALIBRATION_TICKS)) { + pre_end = end; + read_current_timer(&end); + } + read_current_timer(&post_end); + + timer_rate_max = (post_end - pre_start) / + DELAY_CALIBRATION_TICKS; + timer_rate_min = (pre_end - post_start) / + DELAY_CALIBRATION_TICKS; + + /* + * If the upper limit and lower limit of the timer_rate is + * >= 12.5% apart, redo calibration. + */ + if (pre_start != 0 && pre_end != 0 && + (timer_rate_max - timer_rate_min) < (timer_rate_max >> 3)) { + good_timer_count++; + good_timer_sum += timer_rate_max; + } + } + + if (good_timer_count) + return (good_timer_sum/good_timer_count); + + printk(KERN_WARNING "calibrate_delay_direct() failed to get a good " + "estimate for loops_per_jiffy.\nProbably due to long platform interrupts. Consider using \"lpj=\" boot option.\n"); + return 0; +} +#else +static unsigned long __cpuinit calibrate_delay_direct(void) {return 0;} +#endif + +/* + * This is the number of bits of precision for the loops_per_jiffy. Each + * bit takes on average 1.5/HZ seconds. This (like the original) is a little + * better than 1% + * For the boot cpu we can skip the delay calibration and assign it a value + * calculated based on the timer frequency. + * For the rest of the CPUs we cannot assume that the timer frequency is same as + * the cpu frequency, hence do the calibration for those. + */ +#define LPS_PREC 8 + +void __cpuinit calibrate_delay(void) +{ + unsigned long ticks, loopbit; + int lps_precision = LPS_PREC; + + if (preset_lpj) { + loops_per_jiffy = preset_lpj; + printk(KERN_INFO + "Calibrating delay loop (skipped) preset value.. "); + } else if ((smp_processor_id() == 0) && lpj_fine) { + loops_per_jiffy = lpj_fine; + printk(KERN_INFO + "Calibrating delay loop (skipped), " + "value calculated using timer frequency.. "); + } else if ((loops_per_jiffy = calibrate_delay_direct()) != 0) { + printk(KERN_INFO + "Calibrating delay using timer specific routine.. "); + } else { + loops_per_jiffy = (1<<12); + + printk(KERN_INFO "Calibrating delay loop... "); + while ((loops_per_jiffy <<= 1) != 0) { + /* wait for "start of" clock tick */ + ticks = jiffies; + while (ticks == jiffies) + /* nothing */; + /* Go .. */ + ticks = jiffies; + __delay(loops_per_jiffy); + ticks = jiffies - ticks; + if (ticks) + break; + } + + /* + * Do a binary approximation to get loops_per_jiffy set to + * equal one clock (up to lps_precision bits) + */ + loops_per_jiffy >>= 1; + loopbit = loops_per_jiffy; + while (lps_precision-- && (loopbit >>= 1)) { + loops_per_jiffy |= loopbit; + ticks = jiffies; + while (ticks == jiffies) + /* nothing */; + ticks = jiffies; + __delay(loops_per_jiffy); + if (jiffies != ticks) /* longer than 1 tick */ + loops_per_jiffy &= ~loopbit; + } + } + printk(KERN_CONT "%lu.%02lu BogoMIPS (lpj=%lu)\n", + loops_per_jiffy/(500000/HZ), + (loops_per_jiffy/(5000/HZ)) % 100, loops_per_jiffy); +} + +core_initcall(calibrate_delay); |