tnetv107x_wdt.c
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/*
* TNETV107X: Watchdog timer implementation (for reset)
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <asm/io.h>
#include <asm/arch/clock.h>
#define MAX_DIV 0xFFFE0001
struct wdt_regs {
u32 kick_lock;
#define KICK_LOCK_1 0x5555
#define KICK_LOCK_2 0xaaaa
u32 kick;
u32 change_lock;
#define CHANGE_LOCK_1 0x6666
#define CHANGE_LOCK_2 0xbbbb
u32 change;
u32 disable_lock;
#define DISABLE_LOCK_1 0x7777
#define DISABLE_LOCK_2 0xcccc
#define DISABLE_LOCK_3 0xdddd
u32 disable;
u32 prescale_lock;
#define PRESCALE_LOCK_1 0x5a5a
#define PRESCALE_LOCK_2 0xa5a5
u32 prescale;
};
static struct wdt_regs* regs = (struct wdt_regs *)TNETV107X_WDT0_ARM_BASE;
#define wdt_reg_read(reg) __raw_readl(®s->reg)
#define wdt_reg_write(reg, val) __raw_writel((val), ®s->reg)
static int write_prescale_reg(unsigned long prescale_value)
{
wdt_reg_write(prescale_lock, PRESCALE_LOCK_1);
if ((wdt_reg_read(prescale_lock) & 0x3) != 0x1)
return -1;
wdt_reg_write(prescale_lock, PRESCALE_LOCK_2);
if ((wdt_reg_read(prescale_lock) & 0x3) != 0x3)
return -1;
wdt_reg_write(prescale, prescale_value);
return 0;
}
static int write_change_reg(unsigned long initial_timer_value)
{
wdt_reg_write(change_lock, CHANGE_LOCK_1);
if ((wdt_reg_read(change_lock) & 0x3) != 0x1)
return -1;
wdt_reg_write(change_lock, CHANGE_LOCK_2);
if ((wdt_reg_read(change_lock) & 0x3) != 0x3)
return -1;
wdt_reg_write(change, initial_timer_value);
return 0;
}
static int wdt_control(unsigned long disable_value)
{
wdt_reg_write(disable_lock, DISABLE_LOCK_1);
if ((wdt_reg_read(disable_lock) & 0x3) != 0x1)
return -1;
wdt_reg_write(disable_lock, DISABLE_LOCK_2);
if ((wdt_reg_read(disable_lock) & 0x3) != 0x2)
return -1;
wdt_reg_write(disable_lock, DISABLE_LOCK_3);
if ((wdt_reg_read(disable_lock) & 0x3) != 0x3)
return -1;
wdt_reg_write(disable, disable_value);
return 0;
}
static int wdt_set_period(unsigned long msec)
{
unsigned long change_value, count_value;
unsigned long prescale_value = 1;
unsigned long refclk_khz, maxdiv;
int ret;
refclk_khz = clk_get_rate(TNETV107X_LPSC_WDT_ARM);
maxdiv = (MAX_DIV / refclk_khz);
if ((!msec) || (msec > maxdiv))
return -1;
count_value = refclk_khz * msec;
if (count_value > 0xffff) {
change_value = count_value / 0xffff + 1;
prescale_value = count_value / change_value;
} else {
change_value = count_value;
}
ret = write_prescale_reg(prescale_value - 1);
if (ret)
return ret;
ret = write_change_reg(change_value);
if (ret)
return ret;
return 0;
}
unsigned long last_wdt = -1;
int wdt_start(unsigned long msecs)
{
int ret;
ret = wdt_control(0);
if (ret)
return ret;
ret = wdt_set_period(msecs);
if (ret)
return ret;
ret = wdt_control(1);
if (ret)
return ret;
ret = wdt_kick();
last_wdt = msecs;
return ret;
}
int wdt_stop(void)
{
last_wdt = -1;
return wdt_control(0);
}
int wdt_kick(void)
{
wdt_reg_write(kick_lock, KICK_LOCK_1);
if ((wdt_reg_read(kick_lock) & 0x3) != 0x1)
return -1;
wdt_reg_write(kick_lock, KICK_LOCK_2);
if ((wdt_reg_read(kick_lock) & 0x3) != 0x3)
return -1;
wdt_reg_write(kick, 1);
return 0;
}
void reset_cpu(ulong addr)
{
clk_enable(TNETV107X_LPSC_WDT_ARM);
wdt_start(1);
wdt_kick();
}