Date:   Sun, 5 Nov 2017 07:55:18 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andrey Smirnov <andrew.smirnov@...il.com>
Cc:     linux-kernel@...r.kernel.org, linux-watchdog@...r.kernel.org,
        cphealy@...il.com, Lucas Stach <l.stach@...gutronix.de>,
        Nikita Yushchenko <nikita.yoush@...entembedded.com>,
        Lee Jones <lee.jones@...aro.org>, Pavel Machek <pavel@....cz>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Rob Herring <robh@...nel.org>, Johan Hovold <johan@...nel.org>,
        Sebastian Reichel <sebastian.reichel@...labora.co.uk>
Subject: Re: [PATCH v10 4/5] watchdog: Add RAVE SP watchdog driver

On 11/04/2017 04:24 AM, Greg Kroah-Hartman wrote:
> On Tue, Oct 31, 2017 at 09:36:55AM -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>
>> Cc: Sebastian Reichel <sebastian.reichel@...labora.co.uk>
>> 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 | 349 +++++++++++++++++++++++++++++++++++++++++
>>   3 files changed, 357 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..8a2943f7c123
>> --- /dev/null
>> +++ b/drivers/watchdog/rave-sp-wdt.c
>> @@ -0,0 +1,349 @@
>> +/*
>> + *  rave-sp-wdt.c - Watchdog driver present in RAVE SP
>> + *
>> + * Copyright (C) 2017 Zodiac Inflight Innovation
>> + *
>> + * Driver for parent device can be found in drivers/mfd/rave-sp.c
>> + *
>> + * 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/nvmem-consumer.h>
>> +#include <linux/of_device.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/rave-sp.h>
>> +#include <linux/reboot.h>
>> +#include <linux/slab.h>
>> +#include <linux/watchdog.h>
>> +
>> +enum {
>> +	RAVE_SP_RESET_BYTE = 1,
>> +	RAVE_SP_RESET_REASON_NORMAL = 0,
>> +	RAVE_SP_RESET_DELAY_MS = 500,
>> +};
>> +
>> +/**
>> + * struct rave_sp_wdt_variant - RAVE SP watchdog variant
>> + *
>> + * @max_timeout:	Largest possible watchdog timeout setting
>> + * @min_timeout:	Smallest possible watchdog timeout setting
>> + *
>> + * @configure:		Function to send configuration command
>> + * @restart:		Function to send "restart" command
>> + */
>> +struct rave_sp_wdt_variant {
>> +	unsigned int max_timeout;
>> +	unsigned int min_timeout;
>> +
>> +	int (*configure)(struct watchdog_device *, bool);
>> +	int (*restart)(struct watchdog_device *);
>> +};
>> +
>> +/**
>> + * struct rave_sp_wdt - RAVE SP watchdog
>> + *
>> + * @wdd:		Underlying watchdog device
>> + * @sp:			Pointer to parent RAVE SP device
>> + * @variant:		Device specific variant information
>> + * @reboot_notifier:	Reboot notifier implementing machine reset
>> + */
>> +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)
>> +{
>> +	return rave_sp_exec(to_rave_sp_wdt(wdd)->sp,
>> +			    data, data_size, NULL, 0);
>> +}
>> +
>> +static int rave_sp_wdt_legacy_configure(struct watchdog_device *wdd, bool on)
>> +{
>> +	u8 cmd[] = {
>> +		[0] = RAVE_SP_CMD_SW_WDT,
>> +		[1] = 0,
>> +		[2] = 0,
>> +		[3] = on,
>> +		[4] = on ? wdd->timeout : 0,
>> +	};
>> +
>> +	return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
>> +}
>> +
>> +static int rave_sp_wdt_rdu_configure(struct watchdog_device *wdd, bool on)
>> +{
>> +	u8 cmd[] = {
>> +		[0] = RAVE_SP_CMD_SW_WDT,
>> +		[1] = 0,
>> +		[2] = on,
>> +		[3] = (u8)wdd->timeout,
>> +		[4] = (u8)(wdd->timeout >> 8),
>> +	};
>> +
>> +	return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
>> +}
>> +
>> +/**
>> + * rave_sp_wdt_configure - Configure watchdog device
>> + *
>> + * @wdd:	Device to configure
>> + * @on:		Desired state of the watchdog timer (ON/OFF)
>> + *
>> + * This function configures two aspects of the watchdog timer:
>> + *
>> + *  - Wheither it is ON or OFF
>> + *  - Its timeout duration
>> + *
>> + * with first aspect specified via function argument and second via
>> + * the value of 'wdd->timeout'.
>> + */
>> +static int rave_sp_wdt_configure(struct watchdog_device *wdd, bool on)
>> +{
>> +	return to_rave_sp_wdt(wdd)->variant->configure(wdd, on);
>> +}
>> +
>> +static int rave_sp_wdt_legacy_restart(struct watchdog_device *wdd)
>> +{
>> +	u8 cmd[] = {
>> +		[0] = RAVE_SP_CMD_RESET,
>> +		[1] = 0,
>> +		[2] = RAVE_SP_RESET_BYTE
>> +	};
>> +
>> +	return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
>> +}
>> +
>> +static int rave_sp_wdt_rdu_restart(struct watchdog_device *wdd)
>> +{
>> +	u8 cmd[] = {
>> +		[0] = RAVE_SP_CMD_RESET,
>> +		[1] = 0,
>> +		[2] = RAVE_SP_RESET_BYTE,
>> +		[3] = RAVE_SP_RESET_REASON_NORMAL
>> +	};
>> +
>> +	return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
>> +}
>> +
>> +static int rave_sp_wdt_reboot_notifier(struct notifier_block *nb,
>> +				       unsigned long action, void *data)
>> +{
>> +	/*
>> +	 * Restart handler is called in atomic context which means we
>> +	 * can't communicate to SP via UART. Luckily for use SP will
>> +	 * wait 500ms before actually resetting us, so we ask it to do
>> +	 * so here and let the rest of the system go on wrapping
>> +	 * things up.
>> +	 */
>> +	if (action == SYS_DOWN || action == SYS_HALT) {
>> +		struct rave_sp_wdt *sp_wd =
>> +			container_of(nb, struct rave_sp_wdt, reboot_notifier);
>> +
>> +		const int ret = sp_wd->variant->restart(&sp_wd->wdd);
>> +
>> +		if (ret < 0)
>> +			dev_err(sp_wd->wdd.parent,
>> +				"Failed to issue restart command (%d)", ret);
>> +		return NOTIFY_OK;
>> +	}
>> +
>> +	return NOTIFY_DONE;
>> +}
>> +
>> +static int rave_sp_wdt_restart(struct watchdog_device *wdd,
>> +			       unsigned long action, void *data)
>> +{
>> +	/*
>> +	 * The actual work was done by reboot notifier above. SP
>> +	 * firmware waits 500 ms before issuing reset, so let's hang
>> +	 * here for twice that delay and hopefuly we'd never reach
>> +	 * the return statement.
>> +	 */
>> +	mdelay(2 * RAVE_SP_RESET_DELAY_MS);
>> +
>> +	return -EIO;
>> +}
>> +
>> +static int rave_sp_wdt_start(struct watchdog_device *wdd)
>> +{
>> +	int ret;
>> +
>> +	ret = rave_sp_wdt_configure(wdd, true);
>> +	if (!ret)
>> +		set_bit(WDOG_HW_RUNNING, &wdd->status);
>> +
>> +	return ret;
>> +}
>> +
>> +static int rave_sp_wdt_stop(struct watchdog_device *wdd)
>> +{
>> +	return rave_sp_wdt_configure(wdd, false);
>> +}
>> +
>> +static int rave_sp_wdt_set_timeout(struct watchdog_device *wdd,
>> +				   unsigned int timeout)
>> +{
>> +	wdd->timeout = timeout;
>> +
>> +	return rave_sp_wdt_configure(wdd, watchdog_active(wdd));
>> +}
>> +
>> +static int rave_sp_wdt_ping(struct watchdog_device *wdd)
>> +{
>> +	u8 cmd[] = {
>> +		[0] = RAVE_SP_CMD_PET_WDT,
>> +		[1] = 0,
>> +	};
>> +
>> +	return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
>> +}
>> +
>> +static const struct watchdog_info rave_sp_wdt_info = {
>> +	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
>> +	.identity = "RAVE SP Watchdog",
>> +};
>> +
>> +static const struct watchdog_ops rave_sp_wdt_ops = {
>> +	.owner = THIS_MODULE,
>> +	.start = rave_sp_wdt_start,
>> +	.stop = rave_sp_wdt_stop,
>> +	.ping = rave_sp_wdt_ping,
>> +	.set_timeout = rave_sp_wdt_set_timeout,
>> +	.restart = rave_sp_wdt_restart,
>> +};
>> +
>> +static const struct of_device_id rave_sp_wdt_of_match[] = {
>> +	{ .compatible = "zii,rave-sp-watchdog" },
>> +	{}
>> +};
>> +
>> +static const struct rave_sp_wdt_variant rave_sp_wdt_legacy = {
>> +	.max_timeout = 255,
>> +	.min_timeout = 1,
>> +	.configure = rave_sp_wdt_legacy_configure,
>> +	.restart   = rave_sp_wdt_legacy_restart,
>> +};
>> +
>> +static const struct rave_sp_wdt_variant rave_sp_wdt_rdu = {
>> +	.max_timeout = 180,
>> +	.min_timeout = 60,
>> +	.configure = rave_sp_wdt_rdu_configure,
>> +	.restart   = rave_sp_wdt_rdu_restart,
>> +};
>> +
>> +static const struct of_device_id rave_sp_wdt_variants[] = {
>> +	{ .compatible = COMPATIBLE_RAVE_SP_NIU,  .data = &rave_sp_wdt_legacy },
>> +	{ .compatible = COMPATIBLE_RAVE_SP_MEZZ, .data = &rave_sp_wdt_legacy },
>> +	{ .compatible = COMPATIBLE_RAVE_SP_ESB,  .data = &rave_sp_wdt_legacy },
>> +	{ .compatible = COMPATIBLE_RAVE_SP_RDU1, .data = &rave_sp_wdt_rdu    },
>> +	{ .compatible = COMPATIBLE_RAVE_SP_RDU2, .data = &rave_sp_wdt_rdu    },
>> +	{ /* sentinel */ }
>> +};
>> +
>> +static int rave_sp_wdt_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	const struct of_device_id *id;
>> +	struct watchdog_device *wdd;
>> +	struct rave_sp_wdt *sp_wd;
>> +	struct nvmem_cell *cell;
>> +	__le16 timeout = 0;
>> +	int ret;
>> +
>> +	id = of_match_device(rave_sp_wdt_variants, dev->parent);
>> +	if (!id) {
>> +		dev_err(dev, "Unknown parent device variant. Bailing out\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	sp_wd = devm_kzalloc(dev, sizeof(*sp_wd), GFP_KERNEL);
>> +	if (!sp_wd)
>> +		return -ENOMEM;
>> +
>> +	sp_wd->variant = id->data;
>> +	sp_wd->sp      = dev_get_drvdata(dev->parent);
>> +
>> +	wdd              = &sp_wd->wdd;
>> +	wdd->parent      = dev;
>> +	wdd->info        = &rave_sp_wdt_info;
>> +	wdd->ops         = &rave_sp_wdt_ops;
>> +	wdd->min_timeout = sp_wd->variant->min_timeout;
>> +	wdd->max_timeout = sp_wd->variant->max_timeout;
>> +	wdd->status      = WATCHDOG_NOWAYOUT_INIT_STATUS;
>> +	wdd->timeout     = 60;
>> +
>> +	cell = nvmem_cell_get(dev, "wdt-timeout");
>> +	if (!IS_ERR(cell)) {
>> +		size_t len;
>> +		void *value = nvmem_cell_read(cell, &len);
>> +
>> +		if (!IS_ERR(value)) {
>> +			memcpy(&timeout, value, min(len, sizeof(timeout)));
>> +			kfree(value);
>> +		}
>> +		nvmem_cell_put(cell);
>> +	}
>> +	watchdog_init_timeout(wdd, le16_to_cpu(timeout), dev);
>> +	watchdog_set_restart_priority(wdd, 255);
>> +
>> +	sp_wd->reboot_notifier.notifier_call = rave_sp_wdt_reboot_notifier;
>> +	ret = devm_register_reboot_notifier(dev, &sp_wd->reboot_notifier);
>> +	if (ret) {
>> +		dev_err(dev, "Failed to register reboot notifier\n");
>> +		return ret;
>> +	}
>> +
>> +	/*
>> +	 * We don't know if watchdog is running now. To be sure, let's
>> +	 * start it and depend on watchdog core to ping it
>> +	 */
>> +	wdd->max_hw_heartbeat_ms = wdd->max_timeout * 1000;
>> +	ret = rave_sp_wdt_start(wdd);
>> +	if (ret) {
>> +		dev_err(dev, "Watchdog didn't start\n");
>> +		return ret;
>> +	}
>> +
>> +	return devm_watchdog_register_device(dev, wdd);
>> +}
>> +
>> +static struct platform_driver rave_sp_wdt_driver = {
>> +	.probe = rave_sp_wdt_probe,
> 
> No remove?  :)
> 

It would be an empty function.

Guenter

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