This patch adds watchdog support for the Mediatek MT7620 SoC
Reviewed-by: Jagan Teki jagan@amarulasolutions.com Signed-off-by: Weijie Gao weijie.gao@mediatek.com --- v3 changes: add detail comments for mt7620_wdt_expire_now() v2 changes: add expire_now --- drivers/watchdog/Kconfig | 7 ++ drivers/watchdog/Makefile | 1 + drivers/watchdog/mt7620_wdt.c | 142 ++++++++++++++++++++++++++++++++++ 3 files changed, 150 insertions(+) create mode 100644 drivers/watchdog/mt7620_wdt.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index 4532a40e45..7d7bd4dcb7 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -125,6 +125,13 @@ config WDT_MPC8xx help Select this to enable mpc8xx watchdog timer
+config WDT_MT7620 + bool "MediaTek MT7620 watchdog timer support" + depends on WDT && SOC_MT7620 + help + Select this to enable watchdog timer on MediaTek MT7620 and earlier + SoC chips. + config WDT_MT7621 bool "MediaTek MT7621 watchdog timer support" depends on WDT && SOC_MT7628 diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index 01b8231f2b..825b50e626 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -24,6 +24,7 @@ obj-$(CONFIG_WDT_CORTINA) += cortina_wdt.o obj-$(CONFIG_WDT_ORION) += orion_wdt.o obj-$(CONFIG_WDT_CDNS) += cdns_wdt.o obj-$(CONFIG_WDT_MPC8xx) += mpc8xx_wdt.o +obj-$(CONFIG_WDT_MT7620) += mt7620_wdt.o obj-$(CONFIG_WDT_MT7621) += mt7621_wdt.o obj-$(CONFIG_WDT_MTK) += mtk_wdt.o obj-$(CONFIG_WDT_OCTEONTX) += octeontx_wdt.o diff --git a/drivers/watchdog/mt7620_wdt.c b/drivers/watchdog/mt7620_wdt.c new file mode 100644 index 0000000000..8d39010ee7 --- /dev/null +++ b/drivers/watchdog/mt7620_wdt.c @@ -0,0 +1,142 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020 MediaTek Inc. + * + * Author: Weijie Gao weijie.gao@mediatek.com + * + * Watchdog timer for MT7620 and earlier SoCs + */ + +#include <div64.h> +#include <dm.h> +#include <reset.h> +#include <wdt.h> +#include <linux/bitops.h> +#include <linux/io.h> + +struct mt7620_wdt { + void __iomem *regs; + u64 timeout; +}; + +#define TIMER_FREQ 40000000 +#define TIMER_MASK 0xffff +#define TIMER_PRESCALE 65536 + +#define TIMER_LOAD 0x00 +#define TIMER_CTL 0x08 + +#define TIMER_ENABLE BIT(7) +#define TIMER_MODE_SHIFT 4 +#define TIMER_MODE_WDT 3 +#define TIMER_PRESCALE_SHIFT 0 +#define TIMER_PRESCALE_65536 15 + +static void mt7620_wdt_ping(struct mt7620_wdt *priv) +{ + u64 val; + + val = (TIMER_FREQ / TIMER_PRESCALE) * priv->timeout; + do_div(val, 1000); + + if (val > TIMER_MASK) + val = TIMER_MASK; + + writel(val, priv->regs + TIMER_LOAD); +} + +static int mt7620_wdt_start(struct udevice *dev, u64 ms, ulong flags) +{ + struct mt7620_wdt *priv = dev_get_priv(dev); + + priv->timeout = ms; + mt7620_wdt_ping(priv); + + writel(TIMER_ENABLE | (TIMER_MODE_WDT << TIMER_MODE_SHIFT) | + (TIMER_PRESCALE_65536 << TIMER_PRESCALE_SHIFT), + priv->regs + TIMER_CTL); + + return 0; +} + +static int mt7620_wdt_stop(struct udevice *dev) +{ + struct mt7620_wdt *priv = dev_get_priv(dev); + + mt7620_wdt_ping(priv); + + clrbits_32(priv->regs + TIMER_CTL, TIMER_ENABLE); + + return 0; +} + +static int mt7620_wdt_reset(struct udevice *dev) +{ + struct mt7620_wdt *priv = dev_get_priv(dev); + + mt7620_wdt_ping(priv); + + return 0; +} + +static int mt7620_wdt_expire_now(struct udevice *dev, ulong flags) +{ + struct mt7620_wdt *priv = dev_get_priv(dev); + + mt7620_wdt_start(dev, 1, flags); + + /* + * 0 will disable the timer directly, a positive number must be used + * instead. Since the timer is a countdown timer, 1 (tick) is used. + * + * For a timer with input clock = 40MHz, 1 timer tick is short + * enough to trigger a timeout immediately. + * + * Restore prescale to 1, and load timer with 1 to trigger timeout. + */ + writel(TIMER_ENABLE | (TIMER_MODE_WDT << TIMER_MODE_SHIFT), + priv->regs + TIMER_CTL); + writel(1, priv->regs + TIMER_LOAD); + + return 0; +} + +static int mt7620_wdt_probe(struct udevice *dev) +{ + struct mt7620_wdt *priv = dev_get_priv(dev); + struct reset_ctl reset_wdt; + int ret; + + ret = reset_get_by_index(dev, 0, &reset_wdt); + if (!ret) + reset_deassert(&reset_wdt); + + priv->regs = dev_remap_addr(dev); + if (!priv->regs) + return -EINVAL; + + mt7620_wdt_stop(dev); + + return 0; +} + +static const struct wdt_ops mt7620_wdt_ops = { + .start = mt7620_wdt_start, + .reset = mt7620_wdt_reset, + .stop = mt7620_wdt_stop, + .expire_now = mt7620_wdt_expire_now, +}; + +static const struct udevice_id mt7620_wdt_ids[] = { + { .compatible = "mediatek,mt7620-wdt" }, + {} +}; + +U_BOOT_DRIVER(mt7620_wdt) = { + .name = "mt7620_wdt", + .id = UCLASS_WDT, + .of_match = mt7620_wdt_ids, + .probe = mt7620_wdt_probe, + .priv_auto_alloc_size = sizeof(struct mt7620_wdt), + .ops = &mt7620_wdt_ops, +};