armada-37xx-wdt.c
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// SPDX-License-Identifier: GPL-2.0+
/*
* Marvell Armada 37xx SoC Watchdog Driver
*
* Marek Behun <marek.behun@nic.cz>
*/
#include <common.h>
#include <dm.h>
#include <wdt.h>
#include <asm/io.h>
#include <asm/arch/cpu.h>
#include <asm/arch/soc.h>
#include <dm/device_compat.h>
DECLARE_GLOBAL_DATA_PTR;
struct a37xx_wdt {
void __iomem *sel_reg;
void __iomem *reg;
ulong clk_rate;
u64 timeout;
};
/*
* We use Counter 1 as watchdog timer, and Counter 0 for re-triggering Counter 1
*/
#define CNTR_CTRL(id) ((id) * 0x10)
#define CNTR_CTRL_ENABLE 0x0001
#define CNTR_CTRL_ACTIVE 0x0002
#define CNTR_CTRL_MODE_MASK 0x000c
#define CNTR_CTRL_MODE_ONESHOT 0x0000
#define CNTR_CTRL_MODE_HWSIG 0x000c
#define CNTR_CTRL_TRIG_SRC_MASK 0x00f0
#define CNTR_CTRL_TRIG_SRC_PREV_CNTR 0x0050
#define CNTR_CTRL_PRESCALE_MASK 0xff00
#define CNTR_CTRL_PRESCALE_MIN 2
#define CNTR_CTRL_PRESCALE_SHIFT 8
#define CNTR_COUNT_LOW(id) (CNTR_CTRL(id) + 0x4)
#define CNTR_COUNT_HIGH(id) (CNTR_CTRL(id) + 0x8)
static void set_counter_value(struct a37xx_wdt *priv, int id, u64 val)
{
writel(val & 0xffffffff, priv->reg + CNTR_COUNT_LOW(id));
writel(val >> 32, priv->reg + CNTR_COUNT_HIGH(id));
}
static void counter_enable(struct a37xx_wdt *priv, int id)
{
setbits_le32(priv->reg + CNTR_CTRL(id), CNTR_CTRL_ENABLE);
}
static void counter_disable(struct a37xx_wdt *priv, int id)
{
clrbits_le32(priv->reg + CNTR_CTRL(id), CNTR_CTRL_ENABLE);
}
static int init_counter(struct a37xx_wdt *priv, int id, u32 mode, u32 trig_src)
{
u32 reg;
reg = readl(priv->reg + CNTR_CTRL(id));
if (reg & CNTR_CTRL_ACTIVE)
return -EBUSY;
reg &= ~(CNTR_CTRL_MODE_MASK | CNTR_CTRL_PRESCALE_MASK |
CNTR_CTRL_TRIG_SRC_MASK);
/* set mode */
reg |= mode;
/* set prescaler to the min value */
reg |= CNTR_CTRL_PRESCALE_MIN << CNTR_CTRL_PRESCALE_SHIFT;
/* set trigger source */
reg |= trig_src;
writel(reg, priv->reg + CNTR_CTRL(id));
return 0;
}
static int a37xx_wdt_reset(struct udevice *dev)
{
struct a37xx_wdt *priv = dev_get_priv(dev);
if (!priv->timeout)
return -EINVAL;
/* counter 1 is retriggered by forcing end count on counter 0 */
counter_disable(priv, 0);
counter_enable(priv, 0);
return 0;
}
static int a37xx_wdt_expire_now(struct udevice *dev, ulong flags)
{
struct a37xx_wdt *priv = dev_get_priv(dev);
/* first we set timeout to 0 */
counter_disable(priv, 1);
set_counter_value(priv, 1, 0);
counter_enable(priv, 1);
/* and then we start counter 1 by forcing end count on counter 0 */
counter_disable(priv, 0);
counter_enable(priv, 0);
return 0;
}
static int a37xx_wdt_start(struct udevice *dev, u64 ms, ulong flags)
{
struct a37xx_wdt *priv = dev_get_priv(dev);
int err;
err = init_counter(priv, 0, CNTR_CTRL_MODE_ONESHOT, 0);
if (err < 0)
return err;
err = init_counter(priv, 1, CNTR_CTRL_MODE_HWSIG,
CNTR_CTRL_TRIG_SRC_PREV_CNTR);
if (err < 0)
return err;
priv->timeout = ms * priv->clk_rate / 1000 / CNTR_CTRL_PRESCALE_MIN;
set_counter_value(priv, 0, 0);
set_counter_value(priv, 1, priv->timeout);
counter_enable(priv, 1);
/* we have to force end count on counter 0 to start counter 1 */
counter_enable(priv, 0);
return 0;
}
static int a37xx_wdt_stop(struct udevice *dev)
{
struct a37xx_wdt *priv = dev_get_priv(dev);
counter_disable(priv, 1);
counter_disable(priv, 0);
writel(0, priv->sel_reg);
return 0;
}
static int a37xx_wdt_probe(struct udevice *dev)
{
struct a37xx_wdt *priv = dev_get_priv(dev);
fdt_addr_t addr;
addr = dev_read_addr_index(dev, 0);
if (addr == FDT_ADDR_T_NONE)
goto err;
priv->sel_reg = (void __iomem *)addr;
addr = dev_read_addr_index(dev, 1);
if (addr == FDT_ADDR_T_NONE)
goto err;
priv->reg = (void __iomem *)addr;
priv->clk_rate = (ulong)get_ref_clk() * 1000000;
/*
* We use counter 1 as watchdog timer, therefore we only set bit
* TIMER1_IS_WCHDOG_TIMER. Counter 0 is only used to force re-trigger on
* counter 1.
*/
writel(1 << 1, priv->sel_reg);
return 0;
err:
dev_err(dev, "no io address\n");
return -ENODEV;
}
static const struct wdt_ops a37xx_wdt_ops = {
.start = a37xx_wdt_start,
.reset = a37xx_wdt_reset,
.stop = a37xx_wdt_stop,
.expire_now = a37xx_wdt_expire_now,
};
static const struct udevice_id a37xx_wdt_ids[] = {
{ .compatible = "marvell,armada-3700-wdt" },
{}
};
U_BOOT_DRIVER(a37xx_wdt) = {
.name = "armada_37xx_wdt",
.id = UCLASS_WDT,
.of_match = a37xx_wdt_ids,
.probe = a37xx_wdt_probe,
.priv_auto_alloc_size = sizeof(struct a37xx_wdt),
.ops = &a37xx_wdt_ops,
};