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Sender: Guenter Roeck <groeck7@gmail.com>
Subject: Re: [PATCH v2 3/4] watchdog: simatic-ipc-wdt: add new driver for
 Siemens Industrial PCs
To:     Henning Schild <henning.schild@siemens.com>,
        linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org,
        platform-driver-x86@vger.kernel.org, linux-watchdog@vger.kernel.org
Cc:     Srikanth Krishnakar <skrishnakar@gmail.com>,
        Jan Kiszka <jan.kiszka@siemens.com>,
        Gerd Haeussler <gerd.haeussler.ext@siemens.com>,
        Wim Van Sebroeck <wim@linux-watchdog.org>,
        Mark Gross <mgross@linux.intel.com>,
        Hans de Goede <hdegoede@redhat.com>,
        Pavel Machek <pavel@ucw.cz>,
        Andy Shevchenko <andy.shevchenko@gmail.com>
References: <20210315095710.7140-1-henning.schild@siemens.com>
 <20210315095710.7140-4-henning.schild@siemens.com>
From:   Guenter Roeck <linux@roeck-us.net>
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Message-ID: <120cb6ea-a0a8-a0e8-25ec-50d1d2dbe56d@roeck-us.net>
Date:   Mon, 15 Mar 2021 08:10:25 -0700
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On 3/15/21 2:57 AM, Henning Schild wrote:
> This driver adds initial support for several devices from Siemens. It is
> based on a platform driver introduced in an earlier commit.
> 
> Signed-off-by: Henning Schild <henning.schild@siemens.com>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  drivers/watchdog/Kconfig           |  11 ++
>  drivers/watchdog/Makefile          |   1 +
>  drivers/watchdog/simatic-ipc-wdt.c | 215 +++++++++++++++++++++++++++++
>  3 files changed, 227 insertions(+)
>  create mode 100644 drivers/watchdog/simatic-ipc-wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 1fe0042a48d2..948497eb4bef 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -1575,6 +1575,17 @@ config NIC7018_WDT
>  	  To compile this driver as a module, choose M here: the module will be
>  	  called nic7018_wdt.
>  
> +config SIEMENS_SIMATIC_IPC_WDT
> +	tristate "Siemens Simatic IPC Watchdog"
> +	depends on SIEMENS_SIMATIC_IPC
> +	select WATCHDOG_CORE
> +	help
> +	  This driver adds support for several watchdogs found in Industrial
> +	  PCs from Siemens.
> +
> +	  To compile this driver as a module, choose M here: the module will be
> +	  called simatic-ipc-wdt.
> +
>  # M68K Architecture
>  
>  config M54xx_WATCHDOG
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index f3a6540e725e..7f5c73ec058c 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -142,6 +142,7 @@ obj-$(CONFIG_NI903X_WDT) += ni903x_wdt.o
>  obj-$(CONFIG_NIC7018_WDT) += nic7018_wdt.o
>  obj-$(CONFIG_MLX_WDT) += mlx_wdt.o
>  obj-$(CONFIG_KEEMBAY_WATCHDOG) += keembay_wdt.o
> +obj-$(CONFIG_SIEMENS_SIMATIC_IPC_WDT) += simatic-ipc-wdt.o
>  
>  # M68K Architecture
>  obj-$(CONFIG_M54xx_WATCHDOG) += m54xx_wdt.o
> diff --git a/drivers/watchdog/simatic-ipc-wdt.c b/drivers/watchdog/simatic-ipc-wdt.c
> new file mode 100644
> index 000000000000..f0f948968db3
> --- /dev/null
> +++ b/drivers/watchdog/simatic-ipc-wdt.c
> @@ -0,0 +1,215 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Siemens SIMATIC IPC driver for Watchdogs
> + *
> + * Copyright (c) Siemens AG, 2020-2021
> + *
> + * Authors:
> + *  Gerd Haeussler <gerd.haeussler.ext@siemens.com>
> + */
> +
> +#include <linux/device.h>
> +#include <linux/errno.h>
> +#include <linux/init.h>
> +#include <linux/io.h>
> +#include <linux/ioport.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/platform_data/x86/simatic-ipc-base.h>
> +#include <linux/platform_device.h>
> +#include <linux/sizes.h>
> +#include <linux/util_macros.h>
> +#include <linux/watchdog.h>
> +
> +#define WD_ENABLE_IOADR			0x62
> +#define WD_TRIGGER_IOADR		0x66
> +#define GPIO_COMMUNITY0_PORT_ID		0xaf
> +#define PAD_CFG_DW0_GPP_A_23		0x4b8
> +#define SAFE_EN_N_427E			0x01
> +#define SAFE_EN_N_227E			0x04
> +#define WD_ENABLED			0x01
> +#define WD_TRIGGERED			0x80
> +#define WD_MACROMODE			0x02
> +
> +#define TIMEOUT_MIN	2
> +#define TIMEOUT_DEF	64
> +#define TIMEOUT_MAX	64
> +
> +#define GP_STATUS_REG_227E	0x404D	/* IO PORT for SAFE_EN_N on 227E */
> +
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +module_param(nowayout, bool, 0000);
> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
> +		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> +
> +static struct resource gp_status_reg_227e_res =
> +	DEFINE_RES_IO_NAMED(GP_STATUS_REG_227E, SZ_1, KBUILD_MODNAME);
> +
> +static struct resource io_resource =
> +	DEFINE_RES_IO_NAMED(WD_ENABLE_IOADR, SZ_1,
> +			    KBUILD_MODNAME " WD_ENABLE_IOADR");
> +
> +/* the actual start will be discovered with pci, 0 is a placeholder */
> +static struct resource mem_resource =
> +	DEFINE_RES_MEM_NAMED(0, SZ_4, "WD_RESET_BASE_ADR");
> +
> +static u32 wd_timeout_table[] = {2, 4, 6, 8, 16, 32, 48, 64 };
> +static void __iomem *wd_reset_base_addr;
> +
> +static int wd_start(struct watchdog_device *wdd)
> +{
> +	outb(inb(WD_ENABLE_IOADR) | WD_ENABLED, WD_ENABLE_IOADR);
> +	return 0;
> +}
> +
> +static int wd_stop(struct watchdog_device *wdd)
> +{
> +	outb(inb(WD_ENABLE_IOADR) & ~WD_ENABLED, WD_ENABLE_IOADR);
> +	return 0;
> +}
> +
> +static int wd_ping(struct watchdog_device *wdd)
> +{
> +	inb(WD_TRIGGER_IOADR);
> +	return 0;
> +}
> +
> +static int wd_set_timeout(struct watchdog_device *wdd, unsigned int t)
> +{
> +	int timeout_idx = find_closest(t, wd_timeout_table,
> +				       ARRAY_SIZE(wd_timeout_table));
> +
> +	outb((inb(WD_ENABLE_IOADR) & 0xc7) | timeout_idx << 3, WD_ENABLE_IOADR);
> +	wdd->timeout = wd_timeout_table[timeout_idx];
> +	return 0;
> +}
> +
> +static const struct watchdog_info wdt_ident = {
> +	.options	= WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING |
> +			  WDIOF_SETTIMEOUT,
> +	.identity	= KBUILD_MODNAME,
> +};
> +
> +static const struct watchdog_ops wdt_ops = {
> +	.owner		= THIS_MODULE,
> +	.start		= wd_start,
> +	.stop		= wd_stop,
> +	.ping		= wd_ping,
> +	.set_timeout	= wd_set_timeout,
> +};
> +
> +static void wd_secondary_enable(u32 wdtmode)
> +{
> +	u16 resetbit;
> +
> +	/* set safe_en_n so we are not just WDIOF_ALARMONLY */
> +	if (wdtmode == SIMATIC_IPC_DEVICE_227E) {
> +		/* enable SAFE_EN_N on GP_STATUS_REG_227E */
> +		resetbit = inw(GP_STATUS_REG_227E);
> +		outw(resetbit & ~SAFE_EN_N_227E, GP_STATUS_REG_227E);
> +	} else {
> +		/* enable SAFE_EN_N on PCH D1600 */
> +		resetbit = ioread16(wd_reset_base_addr);
> +		iowrite16(resetbit & ~SAFE_EN_N_427E, wd_reset_base_addr);
> +	}
> +}
> +
> +static int wd_setup(u32 wdtmode)
> +{
> +	unsigned int bootstatus = 0;
> +	int timeout_idx;
> +
> +	timeout_idx = find_closest(TIMEOUT_DEF, wd_timeout_table,
> +				   ARRAY_SIZE(wd_timeout_table));
> +
> +	if (inb(WD_ENABLE_IOADR) & WD_TRIGGERED)
> +		bootstatus |= WDIOF_CARDRESET;
> +
> +	/* reset alarm bit, set macro mode, and set timeout */
> +	outb(WD_TRIGGERED | WD_MACROMODE | timeout_idx << 3, WD_ENABLE_IOADR);
> +
> +	wd_secondary_enable(wdtmode);
> +
> +	return bootstatus;
> +}
> +
> +static struct watchdog_device wdd_data = {
> +	.info = &wdt_ident,
> +	.ops = &wdt_ops,
> +	.min_timeout = TIMEOUT_MIN,
> +	.max_timeout = TIMEOUT_MAX
> +};
> +
> +static int simatic_ipc_wdt_probe(struct platform_device *pdev)
> +{
> +	struct simatic_ipc_platform *plat = pdev->dev.platform_data;
> +	struct device *dev = &pdev->dev;
> +	struct resource *res;
> +
> +	switch (plat->devmode) {
> +	case SIMATIC_IPC_DEVICE_227E:
> +		if (!devm_request_region(dev, gp_status_reg_227e_res.start,
> +					 resource_size(&gp_status_reg_227e_res),
> +					 KBUILD_MODNAME)) {
> +			dev_err(dev,
> +				"Unable to register IO resource at %pR\n",
> +				&gp_status_reg_227e_res);
> +			return -EBUSY;
> +		}
> +		fallthrough;
> +	case SIMATIC_IPC_DEVICE_427E:
> +		wdd_data.parent = dev;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	if (!devm_request_region(dev, io_resource.start,
> +				 resource_size(&io_resource),
> +				 io_resource.name)) {
> +		dev_err(dev,
> +			"Unable to register IO resource at %#x\n",
> +			WD_ENABLE_IOADR);
> +		return -EBUSY;
> +	}
> +
> +	if (plat->devmode == SIMATIC_IPC_DEVICE_427E) {
> +		res = &mem_resource;
> +
> +		/* get GPIO base from PCI */
> +		res->start = simatic_ipc_get_membase0(PCI_DEVFN(0x1f, 1));
> +		if (res->start == 0)
> +			return -ENODEV;
> +
> +		/* do the final address calculation */
> +		res->start = res->start + (GPIO_COMMUNITY0_PORT_ID << 16) +
> +			     PAD_CFG_DW0_GPP_A_23;
> +		res->end += res->start;
> +
> +		wd_reset_base_addr = devm_ioremap_resource(dev, res);
> +		if (IS_ERR(wd_reset_base_addr))
> +			return PTR_ERR(wd_reset_base_addr);
> +	}
> +
> +	wdd_data.bootstatus = wd_setup(plat->devmode);
> +	if (wdd_data.bootstatus)
> +		dev_warn(dev, "last reboot caused by watchdog reset\n");
> +
> +	watchdog_set_nowayout(&wdd_data, nowayout);
> +	watchdog_stop_on_reboot(&wdd_data);
> +	return devm_watchdog_register_device(dev, &wdd_data);
> +}
> +
> +static struct platform_driver wdt_driver = {
> +	.probe = simatic_ipc_wdt_probe,
> +	.driver = {
> +		.name = KBUILD_MODNAME,
> +	},
> +};
> +
> +module_platform_driver(wdt_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:" KBUILD_MODNAME);
> +MODULE_AUTHOR("Gerd Haeussler <gerd.haeussler.ext@siemens.com>");
>