+++ /dev/null
-/* linux/arch/arm/plat-samsung/time.c
- *
- * Copyright (C) 2003-2005 Simtec Electronics
- * Ben Dooks, <ben@simtec.co.uk>
- *
- * This program 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.
- *
- * This program 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 this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- */
-
-#include <linux/kernel.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/interrupt.h>
-#include <linux/irq.h>
-#include <linux/err.h>
-#include <linux/clk.h>
-#include <linux/io.h>
-#include <linux/platform_device.h>
-#include <linux/syscore_ops.h>
-
-#include <asm/mach-types.h>
-
-#include <asm/irq.h>
-#include <mach/map.h>
-#include <plat/regs-timer.h>
-#include <mach/regs-irq.h>
-#include <asm/mach/time.h>
-#include <mach/tick.h>
-
-#include <plat/clock.h>
-#include <plat/cpu.h>
-
-static unsigned long timer_startval;
-static unsigned long timer_usec_ticks;
-
-#ifndef TICK_MAX
-#define TICK_MAX (0xffff)
-#endif
-
-#define TIMER_USEC_SHIFT 16
-
-/* we use the shifted arithmetic to work out the ratio of timer ticks
- * to usecs, as often the peripheral clock is not a nice even multiple
- * of 1MHz.
- *
- * shift of 14 and 15 are too low for the 12MHz, 16 seems to be ok
- * for the current HZ value of 200 without producing overflows.
- *
- * Original patch by Dimitry Andric, updated by Ben Dooks
-*/
-
-
-/* timer_mask_usec_ticks
- *
- * given a clock and divisor, make the value to pass into timer_ticks_to_usec
- * to scale the ticks into usecs
-*/
-
-static inline unsigned long
-timer_mask_usec_ticks(unsigned long scaler, unsigned long pclk)
-{
- unsigned long den = pclk / 1000;
-
- return ((1000 << TIMER_USEC_SHIFT) * scaler + (den >> 1)) / den;
-}
-
-/* timer_ticks_to_usec
- *
- * convert timer ticks to usec.
-*/
-
-static inline unsigned long timer_ticks_to_usec(unsigned long ticks)
-{
- unsigned long res;
-
- res = ticks * timer_usec_ticks;
- res += 1 << (TIMER_USEC_SHIFT - 4); /* round up slightly */
-
- return res >> TIMER_USEC_SHIFT;
-}
-
-/***
- * Returns microsecond since last clock interrupt. Note that interrupts
- * will have been disabled by do_gettimeoffset()
- * IRQs are disabled before entering here from do_gettimeofday()
- */
-
-static u32 s3c2410_gettimeoffset(void)
-{
- unsigned long tdone;
- unsigned long tval;
-
- /* work out how many ticks have gone since last timer interrupt */
-
- tval = __raw_readl(S3C2410_TCNTO(4));
- tdone = timer_startval - tval;
-
- /* check to see if there is an interrupt pending */
-
- if (s3c24xx_ostimer_pending()) {
- /* re-read the timer, and try and fix up for the missed
- * interrupt. Note, the interrupt may go off before the
- * timer has re-loaded from wrapping.
- */
-
- tval = __raw_readl(S3C2410_TCNTO(4));
- tdone = timer_startval - tval;
-
- if (tval != 0)
- tdone += timer_startval;
- }
-
- return timer_ticks_to_usec(tdone) * 1000;
-}
-
-
-/*
- * IRQ handler for the timer
- */
-static irqreturn_t
-s3c2410_timer_interrupt(int irq, void *dev_id)
-{
- timer_tick();
- return IRQ_HANDLED;
-}
-
-static struct irqaction s3c2410_timer_irq = {
- .name = "S3C2410 Timer Tick",
- .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
- .handler = s3c2410_timer_interrupt,
-};
-
-#define use_tclk1_12() ( \
- machine_is_bast() || \
- machine_is_vr1000() || \
- machine_is_anubis() || \
- machine_is_osiris())
-
-static struct clk *tin;
-static struct clk *tdiv;
-static struct clk *timerclk;
-
-/*
- * Set up timer interrupt, and return the current time in seconds.
- *
- * Currently we only use timer4, as it is the only timer which has no
- * other function that can be exploited externally
- */
-static void s3c2410_timer_setup (void)
-{
- unsigned long tcon;
- unsigned long tcnt;
- unsigned long tcfg1;
- unsigned long tcfg0;
-
- tcnt = TICK_MAX; /* default value for tcnt */
-
- /* configure the system for whichever machine is in use */
-
- if (use_tclk1_12()) {
- /* timer is at 12MHz, scaler is 1 */
- timer_usec_ticks = timer_mask_usec_ticks(1, 12000000);
- tcnt = 12000000 / HZ;
-
- tcfg1 = __raw_readl(S3C2410_TCFG1);
- tcfg1 &= ~S3C2410_TCFG1_MUX4_MASK;
- tcfg1 |= S3C2410_TCFG1_MUX4_TCLK1;
- __raw_writel(tcfg1, S3C2410_TCFG1);
- } else {
- unsigned long pclk;
- struct clk *tscaler;
-
- /* for the h1940 (and others), we use the pclk from the core
- * to generate the timer values. since values around 50 to
- * 70MHz are not values we can directly generate the timer
- * value from, we need to pre-scale and divide before using it.
- *
- * for instance, using 50.7MHz and dividing by 6 gives 8.45MHz
- * (8.45 ticks per usec)
- */
-
- pclk = clk_get_rate(timerclk);
-
- /* configure clock tick */
-
- timer_usec_ticks = timer_mask_usec_ticks(6, pclk);
-
- tscaler = clk_get_parent(tdiv);
-
- clk_set_rate(tscaler, pclk / 3);
- clk_set_rate(tdiv, pclk / 6);
- clk_set_parent(tin, tdiv);
-
- tcnt = clk_get_rate(tin) / HZ;
- }
-
- tcon = __raw_readl(S3C2410_TCON);
- tcfg0 = __raw_readl(S3C2410_TCFG0);
- tcfg1 = __raw_readl(S3C2410_TCFG1);
-
- /* timers reload after counting zero, so reduce the count by 1 */
-
- tcnt--;
-
- printk(KERN_DEBUG "timer tcon=%08lx, tcnt %04lx, tcfg %08lx,%08lx, usec %08lx\n",
- tcon, tcnt, tcfg0, tcfg1, timer_usec_ticks);
-
- /* check to see if timer is within 16bit range... */
- if (tcnt > TICK_MAX) {
- panic("setup_timer: HZ is too small, cannot configure timer!");
- return;
- }
-
- __raw_writel(tcfg1, S3C2410_TCFG1);
- __raw_writel(tcfg0, S3C2410_TCFG0);
-
- timer_startval = tcnt;
- __raw_writel(tcnt, S3C2410_TCNTB(4));
-
- /* ensure timer is stopped... */
-
- tcon &= ~(7<<20);
- tcon |= S3C2410_TCON_T4RELOAD;
- tcon |= S3C2410_TCON_T4MANUALUPD;
-
- __raw_writel(tcon, S3C2410_TCON);
- __raw_writel(tcnt, S3C2410_TCNTB(4));
- __raw_writel(tcnt, S3C2410_TCMPB(4));
-
- /* start the timer running */
- tcon |= S3C2410_TCON_T4START;
- tcon &= ~S3C2410_TCON_T4MANUALUPD;
- __raw_writel(tcon, S3C2410_TCON);
-}
-
-static void __init s3c2410_timer_resources(void)
-{
- struct platform_device tmpdev;
-
- tmpdev.dev.bus = &platform_bus_type;
- tmpdev.id = 4;
-
- timerclk = clk_get(NULL, "timers");
- if (IS_ERR(timerclk))
- panic("failed to get clock for system timer");
-
- clk_enable(timerclk);
-
- if (!use_tclk1_12()) {
- tmpdev.id = 4;
- tmpdev.dev.init_name = "s3c24xx-pwm.4";
- tin = clk_get(&tmpdev.dev, "pwm-tin");
- if (IS_ERR(tin))
- panic("failed to get pwm-tin clock for system timer");
-
- tdiv = clk_get(&tmpdev.dev, "pwm-tdiv");
- if (IS_ERR(tdiv))
- panic("failed to get pwm-tdiv clock for system timer");
- }
-
- clk_enable(tin);
-}
-
-static struct syscore_ops s3c24xx_syscore_ops = {
- .resume = s3c2410_timer_setup,
-};
-
-void __init s3c24xx_timer_init(void)
-{
- arch_gettimeoffset = s3c2410_gettimeoffset;
-
- s3c2410_timer_resources();
- s3c2410_timer_setup();
- setup_irq(IRQ_TIMER4, &s3c2410_timer_irq);
- register_syscore_ops(&s3c24xx_syscore_ops);
-}
projects / platform / kernel / linux-arm64.git / commitdiff