Date:   Mon, 23 Oct 2017 17:24:09 -0700
From:   Andrey Smirnov <andrew.smirnov@...il.com>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     linux-kernel <linux-kernel@...r.kernel.org>,
        linux-watchdog@...r.kernel.org, Chris Healy <cphealy@...il.com>,
        Lucas Stach <l.stach@...gutronix.de>,
        Nikita Yushchenko <nikita.yoush@...entembedded.com>,
        Lee Jones <lee.jones@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Pavel Machek <pavel@....cz>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Rob Herring <robh@...nel.org>, Johan Hovold <johan@...nel.org>
Subject: Re: [v8,4/5] watchdog: Add RAVE SP watchdog driver

On Mon, Oct 23, 2017 at 3:04 PM, Guenter Roeck <linux@...ck-us.net> wrote:
> On Mon, Oct 23, 2017 at 10:01:42AM -0700, Andrey Smirnov wrote:
>> On Sat, Oct 21, 2017 at 9:47 AM, Guenter Roeck <linux@...ck-us.net> wrote:
>> > On Wed, Oct 18, 2017 at 10:01:35AM -0700, Andrey Smirnov wrote:
>> >> This driver provides access to RAVE SP watchdog functionality.
>> >>
>> >> Cc: linux-kernel@...r.kernel.org
>> >> Cc: linux-watchdog@...r.kernel.org
>> >> Cc: cphealy@...il.com
>> >> Cc: Lucas Stach <l.stach@...gutronix.de>
>> >> Cc: Nikita Yushchenko <nikita.yoush@...entembedded.com>
>> >> Cc: Lee Jones <lee.jones@...aro.org>
>> >> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
>> >> Cc: Pavel Machek <pavel@....cz>
>> >> Cc: Andy Shevchenko <andy.shevchenko@...il.com>
>> >> Cc: Guenter Roeck <linux@...ck-us.net>
>> >> Cc: Rob Herring <robh@...nel.org>
>> >> Cc: Johan Hovold <johan@...nel.org>
>> >> Signed-off-by: Nikita Yushchenko <nikita.yoush@...entembedded.com>
>> >> Signed-off-by: Andrey Smirnov <andrew.smirnov@...il.com>
>> >> ---
>> >>  drivers/watchdog/Kconfig       |   7 +
>> >>  drivers/watchdog/Makefile      |   1 +
>> >>  drivers/watchdog/rave-sp-wdt.c | 310 +++++++++++++++++++++++++++++++++++++++++
>> >>  3 files changed, 318 insertions(+)
>> >>  create mode 100644 drivers/watchdog/rave-sp-wdt.c
>> >>
>> >> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>> >> index c722cbfdc7e6..533a72248cd1 100644
>> >> --- a/drivers/watchdog/Kconfig
>> >> +++ b/drivers/watchdog/Kconfig
>> >> @@ -223,6 +223,13 @@ config ZIIRAVE_WATCHDOG
>> >>         To compile this driver as a module, choose M here: the
>> >>         module will be called ziirave_wdt.
>> >>
>> >> +config RAVE_SP_WATCHDOG
>> >> +     tristate "RAVE SP Watchdog timer"
>> >> +     depends on RAVE_SP_CORE
>> >> +     select WATCHDOG_CORE
>> >> +     help
>> >> +       Support for the watchdog on RAVE SP device.
>> >> +
>> >>  # ALPHA Architecture
>> >>
>> >>  # ARM Architecture
>> >> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
>> >> index 56adf9fa67d0..5c9556c09f6e 100644
>> >> --- a/drivers/watchdog/Makefile
>> >> +++ b/drivers/watchdog/Makefile
>> >> @@ -223,3 +223,4 @@ obj-$(CONFIG_MAX77620_WATCHDOG) += max77620_wdt.o
>> >>  obj-$(CONFIG_ZIIRAVE_WATCHDOG) += ziirave_wdt.o
>> >>  obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
>> >>  obj-$(CONFIG_MENF21BMC_WATCHDOG) += menf21bmc_wdt.o
>> >> +obj-$(CONFIG_RAVE_SP_WATCHDOG) += rave-sp-wdt.o
>> >> diff --git a/drivers/watchdog/rave-sp-wdt.c b/drivers/watchdog/rave-sp-wdt.c
>> >> new file mode 100644
>> >> index 000000000000..86fdc7fb1f92
>> >> --- /dev/null
>> >> +++ b/drivers/watchdog/rave-sp-wdt.c
>> >> @@ -0,0 +1,310 @@
>> >> +/*
>> >> + *  rave-sp-wdt.c - Watchdog driver preseing in RAVE SP
>> >
>> > present ?
>> >
>>
>> Yup, my bad, will fix in v9.
>>
>> >> + *
>> >> + * Copyright (C) 2017 Zodiac Inflight Innovation
>> >> + *
>> >> + * This program is free software; you can redistribute it and/or
>> >> + * modify it under the terms of the GNU General Public License as
>> >> + * published by the Free Software Foundation; either version 2 of
>> >> + * the License, or (at your option) any later version.
>> >> + *
>> >> + * This program is distributed in the hope that it will be useful,
>> >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> >> + * GNU General Public License for more details.
>> >> + *
>> >> + * You should have received a copy of the GNU General Public License
>> >> + * along with this program; if not, see <http://www.gnu.org/licenses/>.
>> >> + */
>> >> +
>> >> +#include <linux/delay.h>
>> >> +#include <linux/kernel.h>
>> >> +#include <linux/module.h>
>> >> +#include <linux/of_device.h>
>> >> +#include <linux/platform_device.h>
>> >> +#include <linux/rave-sp.h>
>> >> +#include <linux/watchdog.h>
>> >> +#include <linux/nvmem-consumer.h>
>> >> +#include <linux/reboot.h>
>> >> +#include <linux/slab.h>
>> >
>> > Alphabetic order please.
>> >
>>
>> OK, will do.
>>
>> >> +
>> >> +enum {
>> >> +     RAVE_SP_RESET_BYTE = 1,
>> >> +     RAVE_SP_RESET_REASON_NORMAL = 0,
>> >> +     RAVE_SP_RESET_DELAY_MS = 500,
>> >> +};
>> >> +
>> >> +struct rave_sp_wdt_variant {
>> >> +     unsigned int max_timeout;
>> >> +     unsigned int min_timeout;
>> >> +
>> >> +     int (*configure)(struct watchdog_device *);
>> >> +     int (*restart)(struct watchdog_device *);
>> >> +};
>> >> +
>> >> +struct rave_sp_wdt {
>> >> +     struct watchdog_device wdd;
>> >> +     struct rave_sp *sp;
>> >> +     const struct rave_sp_wdt_variant *variant;
>> >> +     struct notifier_block reboot_notifier;
>> >> +};
>> >> +
>> >> +static struct rave_sp_wdt *to_rave_sp_wdt(struct watchdog_device *wdd)
>> >> +{
>> >> +     return container_of(wdd, struct rave_sp_wdt, wdd);
>> >> +}
>> >> +
>> >> +static int __rave_sp_wdt_exec(struct watchdog_device *wdd,
>> >> +                           void *data,  size_t data_size,
>> >> +                           void *reply, size_t reply_size)
>> >> +{
>> >> +     return rave_sp_exec(to_rave_sp_wdt(wdd)->sp,
>> >> +                         data, data_size, reply, reply_size);
>> >> +}
>> >
>> > This extra function is only called once and thus quite pointless.
>> >
>>
>> True. Will remove in v9.
>>
>> >> +
>> >> +static int rave_sp_wdt_exec(struct watchdog_device *wdd, void *data,
>> >> +                         size_t data_size)
>> >> +{
>> >> +     return __rave_sp_wdt_exec(wdd, data, data_size, NULL, 0);
>> >> +}
>> >> +
>> >> +
>> >
>> > Please run checkpatch --strict and fix what it reports.
>> >
>>
>> Sure, will do.
>>
>> >> +static int rave_sp_wdt_legacy_configure(struct watchdog_device *wdd)
>> >> +{
>> >> +     const bool enable = watchdog_hw_running(wdd);
>> >> +     u8 cmd[] = {
>> >> +             [0] = RAVE_SP_CMD_SW_WDT,
>> >> +             [1] = 0,
>> >> +             [2] = 0,
>> >> +             [3] = !!enable,
>> >
>> > Useless !!. It converts a boolean to a boolean. Besides, isn't it always
>> > true anyway ?
>>
>> Good point, will remove the "!!". This function also is called as
>> .stop method (via rave_sp_wdt_configure) for corresponding
>> "watchdog_device" and I rely on code in watchdog_stop() to clear
>> WDOG_HW_RUNNING. Is this not a correct thing to do?
>>
>> >
>> >> +             [4] = enable ? wdd->timeout : 0,
>> >> +     };
>> >
>> > Interesting; checkpatch doesn't require an empty line after variable
>> > declarations anymore ? Lets keep it anyway for consistency.
>> >
>>
>> OK, will fix in v9.
>>
>> >> +     return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
>> >> +}
>> >> +
>> >> +static int rave_sp_wdt_rdu_configure(struct watchdog_device *wdd)
>> >> +{
>> >> +     u8 cmd[] = {
>> >> +             [0] = RAVE_SP_CMD_SW_WDT,
>> >> +             [1] = 0,
>> >> +             [2] = watchdog_hw_running(wdd),
>> >
>> > Nitpick, but isn't this always true ? There is no stop function,
>> > and HW_RUNNING is set before this function is called.
>> >
>>
>> Same as above. Let me know if relying on HW_RUNNING being cleared by
>> watchdog_stop() is incorrect.
>>
> Yes, it is incorrect; the knowledge that the flag is cleared before calling
> the driver stop function is not part of the API. You should pass that in as
> flag.

Good to know. Will fix in v9, then.

Thanks,
Andrey Smirnov

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