u-boot/drivers/timer/riscv_timer.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2020, Sean Anderson <seanga2@gmail.com>
* Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
* Copyright (C) 2018, Anup Patel <anup@brainfault.org>
* Copyright (C) 2012 Regents of the University of California
*
* RISC-V architecturally-defined generic timer driver
*
* This driver provides generic timer support for S-mode U-Boot.
*/
#include <common.h>
#include <dm.h>
#include <errno.h>
#include <timer.h>
#include <asm/csr.h>
static u64 notrace riscv_timer_get_count(struct udevice *dev)
{
__maybe_unused u32 hi, lo;
if (IS_ENABLED(CONFIG_64BIT))
return csr_read(CSR_TIME);
do {
hi = csr_read(CSR_TIMEH);
lo = csr_read(CSR_TIME);
} while (hi != csr_read(CSR_TIMEH));
return ((u64)hi << 32) | lo;
}
#if CONFIG_IS_ENABLED(RISCV_SMODE) && IS_ENABLED(CONFIG_TIMER_EARLY)
/**
* timer_early_get_rate() - Get the timer rate before driver model
*/
unsigned long notrace timer_early_get_rate(void)
{
return RISCV_SMODE_TIMER_FREQ;
}
/**
* timer_early_get_count() - Get the timer count before driver model
*
*/
u64 notrace timer_early_get_count(void)
{
return riscv_timer_get_count(NULL);
}
#endif
static int riscv_timer_probe(struct udevice *dev)
{
struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
/* clock frequency was passed from the cpu driver as driver data */
uc_priv->clock_rate = dev->driver_data;
return 0;
}
static const struct timer_ops riscv_timer_ops = {
.get_count = riscv_timer_get_count,
};
U_BOOT_DRIVER(riscv_timer) = {
.name = "riscv_timer",
.id = UCLASS_TIMER,
.probe = riscv_timer_probe,
.ops = &riscv_timer_ops,
.flags = DM_FLAG_PRE_RELOC,
};