diff options
Diffstat (limited to 'target/linux/ubicom32/files/arch/ubicom32/kernel/time.c')
| -rw-r--r-- | target/linux/ubicom32/files/arch/ubicom32/kernel/time.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/target/linux/ubicom32/files/arch/ubicom32/kernel/time.c b/target/linux/ubicom32/files/arch/ubicom32/kernel/time.c new file mode 100644 index 000000000..4a99284bd --- /dev/null +++ b/target/linux/ubicom32/files/arch/ubicom32/kernel/time.c @@ -0,0 +1,212 @@ +/* + * arch/ubicom32/kernel/time.c + * Initialize the timer list and start the appropriate timers. + * + * (C) Copyright 2009, Ubicom, Inc. + * Copyright (C) 1991, 1992, 1995 Linus Torvalds + * + * This file is part of the Ubicom32 Linux Kernel Port. + * + * The Ubicom32 Linux Kernel Port is free software: you can redistribute + * it and/or modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, either version 2 of the + * License, or (at your option) any later version. + * + * The Ubicom32 Linux Kernel Port is distributed in the hope that it + * will be useful, but WITHOUT ANY WARRANTY; without even the implied + * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See + * the GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with the Ubicom32 Linux Kernel Port. If not, + * see <http://www.gnu.org/licenses/>. + * + * Ubicom32 implementation derived from (with many thanks): + * arch/m68knommu + * arch/blackfin + * arch/parisc + */ + +#include <linux/profile.h> +#include <linux/smp.h> +#include <asm/ip5000.h> +#include <asm/machdep.h> + +/* + * A bitmap of the timers on the processor indicates + * that the timer is free or in-use. + */ +static unsigned int timers; + +/* + * timer_set() + * Init the specified compare register to go off <n> cycles from now. + */ +void timer_set(int timervector, unsigned int cycles) +{ + int idx = UBICOM32_VECTOR_TO_TIMER_INDEX(timervector); + UBICOM32_IO_TIMER->syscom[idx] = + UBICOM32_IO_TIMER->sysval + cycles; + ldsr_enable_vector(timervector); +} + +/* + * timer_reset() + * Set/reset the timer to go off again. + * + * Because sysval is a continuous timer, this function is able + * to ensure that we do not have clock sku by using the previous + * value in syscom to set the next value for syscom. + * + * Returns the number of ticks that transpired since the last event. + */ +int timer_reset(int timervector, unsigned int cycles) +{ + /* + * Reset the timer in the LDSR thread to go off appropriately. + * + * Use the previous value of the timer to calculate the new stop + * time. This allows us to account for it taking an + * indeterminate amount of time to get here. + */ + const int timer_index = UBICOM32_VECTOR_TO_TIMER_INDEX(timervector); + unsigned int prev = UBICOM32_IO_TIMER->syscom[timer_index]; + unsigned int next = prev + cycles; + int scratchpad3; + int diff; + int ticks = 1; + + /* + * If the difference is negative, we have missed at least one + * timer tick. + * + * TODO: Decide if we want to "ignore" time (as done below) or + * if we want to process time (unevenly) by calling timer_tick() + * lost_ticks times. + */ + while (1) { + /* + * Set our future time first. + */ + UBICOM32_IO_TIMER->syscom[timer_index] = next; + + /* + * Then check if we are really set time in the futrue. + */ + diff = (int)next - (int)UBICOM32_IO_TIMER->sysval; + if (diff >= 0) { + break; + } + + /* + * Oops, we are too slow. Playing catch up. + * + * If the debugger is connected the there is a good + * chance that we lost time because we were in a + * break-point, so in this case we do not print out + * diagnostics. + */ + asm volatile ("move.4 %0, scratchpad3" + : "=r" (scratchpad3)); + if ((scratchpad3 & 0x1) == 0) { + /* + * No debugger attached, print to the console + */ + printk(KERN_EMERG "diff: %d, timer has lost %u " + "ticks [rounded up]\n", + -diff, + (unsigned int)((-diff + cycles - 1) / cycles)); + } + + do { + next += cycles; + diff = (int)next - (int)UBICOM32_IO_TIMER->sysval; + ticks++; + } while (diff < 0); + } + return ticks; +} + +/* + * sched_clock() + * Returns current time in nano-second units. + * + * Notes: + * 1) This is an override for the weak alias in + * kernel/sched_clock.c. + * 2) Do not use xtime_lock as this function is + * sometimes called with xtime_lock held. + * 3) We use a retry algorithm to ensure that + * we get a consistent value. + * 4) sched_clock must be overwritten if IRQ tracing + * is enabled because the default implementation uses + * the xtime_lock sequence while holding xtime_lock. + */ +unsigned long long sched_clock(void) +{ + unsigned long long my_jiffies; + unsigned long jiffies_top; + unsigned long jiffies_bottom; + + do { + jiffies_top = jiffies_64 >> 32; + jiffies_bottom = jiffies_64 & 0xffffffff; + } while (unlikely(jiffies_top != (unsigned long)(jiffies_64 >> 32))); + + my_jiffies = ((unsigned long long)jiffies_top << 32) | (jiffies_bottom); + return (my_jiffies - INITIAL_JIFFIES) * (NSEC_PER_SEC / HZ); +} + +/* + * timer_free() + * Free a hardware timer. + */ +void timer_free(int interrupt) +{ + unsigned int bit = interrupt - TIMER_INT(0); + + /* + * The timer had not been allocated. + */ + BUG_ON(timers & (1 << bit)); + timers |= (1 << bit); +} + +/* + * timer_alloc() + * Allocate a hardware timer. + */ +int timer_alloc(void) +{ + unsigned int bit = find_first_bit((unsigned long *)&timers, 32); + if (!bit) { + printk(KERN_WARNING "no more free timers\n"); + return -1; + } + + timers &= ~(1 << bit); + return bit + TIMER_INT(0); +} + +/* + * time_init() + * Time init function. + */ +void time_init(void) +{ + /* + * Find the processor node and determine what timers are + * available for us. + */ + timers = processor_timers(); + if (timers == 0) { + printk(KERN_WARNING "no timers are available for Linux\n"); + return; + } + +#ifdef CONFIG_GENERIC_CLOCKEVENTS + timer_device_init(); +#else + timer_tick_init(); +#endif +} |