mirror of
https://github.com/AsahiLinux/u-boot
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83d290c56f
When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
119 lines
2.4 KiB
C
119 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Cirrus Logic EP93xx timer support.
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*
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* Copyright (C) 2009, 2010 Matthias Kaehlcke <matthias@kaehlcke.net>
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*
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* Copyright (C) 2004, 2005
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* Cory T. Tusar, Videon Central, Inc., <ctusar@videon-central.com>
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*
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* Based on the original intr.c Cirrus Logic EP93xx Rev D. interrupt support,
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* author unknown.
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*/
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#include <common.h>
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#include <linux/types.h>
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#include <asm/arch/ep93xx.h>
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#include <asm/io.h>
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#include <div64.h>
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#define TIMER_CLKSEL (1 << 3)
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#define TIMER_ENABLE (1 << 7)
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#define TIMER_FREQ 508469 /* ticks / second */
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#define TIMER_MAX_VAL 0xFFFFFFFF
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static struct ep93xx_timer
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{
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unsigned long long ticks;
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unsigned long last_read;
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} timer;
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static inline unsigned long long usecs_to_ticks(unsigned long usecs)
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{
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unsigned long long ticks = (unsigned long long)usecs * TIMER_FREQ;
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do_div(ticks, 1000 * 1000);
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return ticks;
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}
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static inline void read_timer(void)
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{
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struct timer_regs *timer_regs = (struct timer_regs *)TIMER_BASE;
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const unsigned long now = TIMER_MAX_VAL - readl(&timer_regs->timer3.value);
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if (now >= timer.last_read)
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timer.ticks += now - timer.last_read;
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else
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/* an overflow occurred */
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timer.ticks += TIMER_MAX_VAL - timer.last_read + now;
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timer.last_read = now;
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}
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/*
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* Get the number of ticks (in CONFIG_SYS_HZ resolution)
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*/
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unsigned long long get_ticks(void)
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{
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unsigned long long sys_ticks;
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read_timer();
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sys_ticks = timer.ticks * CONFIG_SYS_HZ;
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do_div(sys_ticks, TIMER_FREQ);
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return sys_ticks;
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}
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unsigned long get_timer_masked(void)
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{
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return get_ticks();
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}
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unsigned long get_timer(unsigned long base)
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{
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return get_timer_masked() - base;
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}
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void __udelay(unsigned long usec)
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{
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unsigned long long target;
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read_timer();
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target = timer.ticks + usecs_to_ticks(usec);
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while (timer.ticks < target)
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read_timer();
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}
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int timer_init(void)
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{
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struct timer_regs *timer_regs = (struct timer_regs *)TIMER_BASE;
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/* use timer 3 with 508KHz and free running, not enabled now */
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writel(TIMER_CLKSEL, &timer_regs->timer3.control);
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/* set initial timer value */
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writel(TIMER_MAX_VAL, &timer_regs->timer3.load);
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/* Enable the timer */
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writel(TIMER_ENABLE | TIMER_CLKSEL,
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&timer_regs->timer3.control);
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/* Reset the timer */
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read_timer();
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timer.ticks = 0;
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return 0;
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}
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/*
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* This function is derived from PowerPC code (timebase clock frequency).
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* On ARM it returns the number of timer ticks per second.
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*/
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unsigned long get_tbclk(void)
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{
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return CONFIG_SYS_HZ;
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}
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