u-boot/drivers/timer/altera_timer.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2000-2002
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*
* (C) Copyright 2004, Psyent Corporation <www.psyent.com>
* Scott McNutt <smcnutt@psyent.com>
*/
#include <common.h>
#include <dm.h>
#include <errno.h>
#include <timer.h>
#include <asm/io.h>
#include <linux/bitops.h>
/* control register */
#define ALTERA_TIMER_CONT BIT(1) /* Continuous mode */
#define ALTERA_TIMER_START BIT(2) /* Start timer */
#define ALTERA_TIMER_STOP BIT(3) /* Stop timer */
struct altera_timer_regs {
u32 status; /* Timer status reg */
u32 control; /* Timer control reg */
u32 periodl; /* Timeout period low */
u32 periodh; /* Timeout period high */
u32 snapl; /* Snapshot low */
u32 snaph; /* Snapshot high */
};
struct altera_timer_plat {
struct altera_timer_regs *regs;
};
static u64 altera_timer_get_count(struct udevice *dev)
{
struct altera_timer_plat *plat = dev_get_plat(dev);
struct altera_timer_regs *const regs = plat->regs;
u32 val;
/* Trigger update */
writel(0x0, &regs->snapl);
/* Read timer value */
val = readl(&regs->snapl) & 0xffff;
val |= (readl(&regs->snaph) & 0xffff) << 16;
return timer_conv_64(~val);
}
static int altera_timer_probe(struct udevice *dev)
{
struct altera_timer_plat *plat = dev_get_plat(dev);
struct altera_timer_regs *const regs = plat->regs;
writel(0, &regs->status);
writel(0, &regs->control);
writel(ALTERA_TIMER_STOP, &regs->control);
writel(0xffff, &regs->periodl);
writel(0xffff, &regs->periodh);
writel(ALTERA_TIMER_CONT | ALTERA_TIMER_START, &regs->control);
return 0;
}
static int altera_timer_of_to_plat(struct udevice *dev)
{
struct altera_timer_plat *plat = dev_get_plat(dev);
plat->regs = map_physmem(dev_read_addr(dev),
sizeof(struct altera_timer_regs),
MAP_NOCACHE);
return 0;
}
static const struct timer_ops altera_timer_ops = {
.get_count = altera_timer_get_count,
};
static const struct udevice_id altera_timer_ids[] = {
{ .compatible = "altr,timer-1.0" },
{}
};
U_BOOT_DRIVER(altera_timer) = {
.name = "altera_timer",
.id = UCLASS_TIMER,
.of_match = altera_timer_ids,
.of_to_plat = altera_timer_of_to_plat,
.plat_auto = sizeof(struct altera_timer_plat),
.probe = altera_timer_probe,
.ops = &altera_timer_ops,
};