On Mon, 2020-11-02 at 11:32 +0530, Jagan Teki wrote:
> On Fri, Oct 30, 2020 at 3:04 PM Weijie Gao <weijie....@mediatek.com> wrote:
> >
> > This patch adds watchdog support for the Mediatek MT7620 SoC
> >
> > Signed-off-by: Weijie Gao <weijie....@mediatek.com>
> > ---
> > v2 changes: add expire_now
> > ---
> > drivers/watchdog/Kconfig | 7 ++
> > drivers/watchdog/Makefile | 1 +
> > drivers/watchdog/mt7620_wdt.c | 132 ++++++++++++++++++++++++++++++++++
> > 3 files changed, 140 insertions(+)
> > create mode 100644 drivers/watchdog/mt7620_wdt.c
> >
> > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> > index 210d9f8093..35d078caa0 100644
> > --- a/drivers/watchdog/Kconfig
> > +++ b/drivers/watchdog/Kconfig
> > @@ -124,6 +124,13 @@ 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..2643167f8f
> > --- /dev/null
> > +++ b/drivers/watchdog/mt7620_wdt.c
> > @@ -0,0 +1,132 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2020 MediaTek Inc.
> > + *
> > + * Author: Weijie Gao <weijie....@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, so use 1 instead */
> > + writel(1, priv->regs + TIMER_LOAD);
>
> Better replace the magic number with macro.
> Otherwise,
this line means load timer with value 1. Since the timer is a countdown,
1 is the smallest value to cause a wdt timeout.
>
> Reviewed-by: Jagan Teki <ja...@amarulasolutions.com>
