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Date:   Thu, 4 Mar 2021 10:00:38 +0100
From:   Henning Schild <henning.schild@siemens.com>
To:     Andy Shevchenko <andy.shevchenko@gmail.com>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-leds@vger.kernel.org" <linux-leds@vger.kernel.org>,
        "platform-driver-x86@vger.kernel.org" 
        <platform-driver-x86@vger.kernel.org>,
        "linux-watchdog@vger.kernel.org" <linux-watchdog@vger.kernel.org>,
        Srikanth Krishnakar <skrishnakar@gmail.com>,
        Jan Kiszka <jan.kiszka@siemens.com>,
        Gerd Haeussler <gerd.haeussler.ext@siemens.com>,
        Guenter Roeck <linux@roeck-us.net>,
        Wim Van Sebroeck <wim@linux-watchdog.org>,
        Mark Gross <mgross@linux.intel.com>,
        Hans de Goede <hdegoede@redhat.com>,
        Pavel Machek <pavel@ucw.cz>
Subject: Re: [PATCH 3/4] watchdog: simatic-ipc-wdt: add new driver for
 Siemens Industrial PCs
Message-ID: <20210304100038.01318bcd@md1za8fc.ad001.siemens.net>
In-Reply-To: <CAHp75VdUXWDg-2o8fmeo7EoMtRLfCnFOw5ptwjXTv9fKMmHv2A@mail.gmail.com>
References: <20210302163309.25528-1-henning.schild@siemens.com>
        <20210302163309.25528-4-henning.schild@siemens.com>
        <CAHp75VdUXWDg-2o8fmeo7EoMtRLfCnFOw5ptwjXTv9fKMmHv2A@mail.gmail.com>
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Am Thu, 4 Mar 2021 10:27:07 +0200
schrieb Andy Shevchenko <andy.shevchenko@gmail.com>:

> On Tuesday, March 2, 2021, Henning Schild <henning.schild@siemens.com>
> wrote:
> 
> > From: Henning Schild <henning.schild@siemens.com>
> >
> > This driver adds initial support for several devices from Siemens.
> > It is based on a platform driver introduced in an earlier commit.
> >
> >  
> 
> Is it ACPI based? Why it can not provide WDAT table instead?

Yes it is. We strongly urged the BIOS guys to look into that for future
products and BIOS updates for current products. But for existing
products they will not add "features". One fear is breaking Windows
where custom drivers have been the way they did it so far.

So we are dealing with legacy here, that is why. Hope that is not a
show-stopper.

Maybe we can carry ACPI quirk snippets instead, did not yet look into
this. And i am not sure which version would be easier to maintain and
more acceptable to the kernel.

regards,
Henning

> 
> > Signed-off-by: Gerd Haeussler <gerd.haeussler.ext@siemens.com>
> > Signed-off-by: Henning Schild <henning.schild@siemens.com>
> > ---
> >  drivers/watchdog/Kconfig           |  11 ++
> >  drivers/watchdog/Makefile          |   1 +
> >  drivers/watchdog/simatic-ipc-wdt.c | 305
> > +++++++++++++++++++++++++++++ 3 files changed, 317 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..b5c8b7ceb404
> > --- /dev/null
> > +++ b/drivers/watchdog/simatic-ipc-wdt.c
> > @@ -0,0 +1,305 @@
> > +// 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>
> > + *
> > + * This program is free software; you can redistribute it and/or
> > modify
> > + * it under the terms of the GNU General Public License version 2
> > as
> > + * published by the Free Software Foundation.
> > + */
> > +
> > +#include <linux/device.h>
> > +#include <linux/init.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/errno.h>
> > +#include <linux/watchdog.h>
> > +#include <linux/ioport.h>
> > +#include <linux/sizes.h>
> > +#include <linux/io.h>
> > +#include <linux/platform_data/x86/simatic-ipc-base.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 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 DEFINE_SPINLOCK(io_lock);       /* the lock for io
> > operations */ +static struct watchdog_device wdd;
> > +
> > +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 get_timeout_idx(u32 timeout)
> > +{
> > +       int i;
> > +
> > +       i = ARRAY_SIZE(wd_timeout_table) - 1;
> > +       for (; i >= 0; i--) {
> > +               if (timeout >= wd_timeout_table[i])
> > +                       break;
> > +       }
> > +
> > +       return i;
> > +}
> > +
> > +static int wd_start(struct watchdog_device *wdd)
> > +{
> > +       u8 regval;
> > +
> > +       spin_lock(&io_lock);
> > +
> > +       regval = inb(WD_ENABLE_IOADR);
> > +       regval |= WD_ENABLED;
> > +       outb(regval, WD_ENABLE_IOADR);
> > +
> > +       spin_unlock(&io_lock);
> > +
> > +       return 0;
> > +}
> > +
> > +static int wd_stop(struct watchdog_device *wdd)
> > +{
> > +       u8 regval;
> > +
> > +       spin_lock(&io_lock);
> > +
> > +       regval = inb(WD_ENABLE_IOADR);
> > +       regval &= ~WD_ENABLED;
> > +       outb(regval, WD_ENABLE_IOADR);
> > +
> > +       spin_unlock(&io_lock);
> > +
> > +       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) +{
> > +       u8 regval;
> > +       int timeout_idx = get_timeout_idx(t);
> > +
> > +       spin_lock(&io_lock);
> > +
> > +       regval = inb(WD_ENABLE_IOADR) & 0xc7;
> > +       regval |= timeout_idx << 3;
> > +       outb(regval, WD_ENABLE_IOADR);
> > +
> > +       spin_unlock(&io_lock);
> > +       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_set_safe_en_n(u32 wdtmode, bool safe_en_n)
> > +{
> > +       u16 resetbit;
> > +
> > +       if (wdtmode == SIMATIC_IPC_DEVICE_227E) {
> > +               /* enable SAFE_EN_N on GP_STATUS_REG_227E */
> > +               resetbit = inw(GP_STATUS_REG_227E);
> > +               if (safe_en_n)
> > +                       resetbit &= ~SAFE_EN_N_227E;
> > +               else
> > +                       resetbit |= SAFE_EN_N_227E;
> > +
> > +               outw(resetbit, GP_STATUS_REG_227E);
> > +       } else {
> > +               /* enable SAFE_EN_N on PCH D1600 */
> > +               resetbit = ioread16(wd_reset_base_addr);
> > +
> > +               if (safe_en_n)
> > +                       resetbit &= ~SAFE_EN_N_427E;
> > +               else
> > +                       resetbit |= SAFE_EN_N_427E;
> > +
> > +               iowrite16(resetbit, wd_reset_base_addr);
> > +       }
> > +}
> > +
> > +static int wd_setup(u32 wdtmode, bool safe_en_n)
> > +{
> > +       u8 regval;
> > +       int timeout_idx = 0;
> > +       bool alarm_active;
> > +
> > +       timeout_idx = get_timeout_idx(TIMEOUT_DEF);
> > +
> > +       wd_set_safe_en_n(wdtmode, safe_en_n);
> > +
> > +       /* read wd register to determine alarm state */
> > +       regval = inb(WD_ENABLE_IOADR);
> > +       if (regval & 0x80) {
> > +               pr_warn("Watchdog alarm active.\n");
> > +               regval = 0x82;  /* use only macro mode, reset alarm
> > bit */
> > +               alarm_active = true;
> > +       } else {
> > +               regval = 0x02;  /* use only macro mode */
> > +               alarm_active = false;
> > +       }
> > +
> > +       regval |= timeout_idx << 3;
> > +       if (nowayout)
> > +               regval |= WD_ENABLED;
> > +
> > +       outb(regval, WD_ENABLE_IOADR);
> > +
> > +       return alarm_active;
> > +}
> > +
> > +static int simatic_ipc_wdt_probe(struct platform_device *pdev)
> > +{
> > +       struct device *dev = &pdev->dev;
> > +       int rc = 0;
> > +       struct simatic_ipc_platform *plat = pdev->dev.platform_data;
> > +       struct resource *res;
> > +
> > +       pr_debug(KBUILD_MODNAME ":%s(#%d) WDT mode: %d\n",
> > +                __func__, __LINE__, plat->devmode);
> > +
> > +       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.info = &wdt_ident;
> > +               wdd.ops = &wdt_ops;
> > +               wdd.min_timeout = TIMEOUT_MIN;
> > +               wdd.max_timeout = TIMEOUT_MAX;
> > +               wdd.parent = NULL;
> > +               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 -ENOMEM;
> > +       }
> > +
> > +       wdd.bootstatus = wd_setup(plat->devmode, true);
> > +       if (wdd.bootstatus)
> > +               pr_warn(KBUILD_MODNAME ": last reboot caused by
> > watchdog reset\n");
> > +
> > +       watchdog_set_nowayout(&wdd, nowayout);
> > +       watchdog_stop_on_reboot(&wdd);
> > +
> > +       rc = devm_watchdog_register_device(dev, &wdd);
> > +
> > +       if (rc == 0)
> > +               pr_debug("initialized. nowayout=%d\n",
> > +                        nowayout);
> > +
> > +       return rc;
> > +}
> > +
> > +static int simatic_ipc_wdt_remove(struct platform_device *pdev)
> > +{
> > +       struct simatic_ipc_platform *plat = pdev->dev.platform_data;
> > +
> > +       wd_setup(plat->devmode, false);
> > +       return 0;
> > +}
> > +
> > +static struct platform_driver wdt_driver = {
> > +       .probe = simatic_ipc_wdt_probe,
> > +       .remove = simatic_ipc_wdt_remove,
> > +       .driver = {
> > +               .name = KBUILD_MODNAME,
> > +       },
> > +};
> > +
> > +static int __init simatic_ipc_wdt_init(void)
> > +{
> > +       return platform_driver_register(&wdt_driver);
> > +}
> > +
> > +static void __exit simatic_ipc_wdt_exit(void)
> > +{
> > +       platform_driver_unregister(&wdt_driver);
> > +}
> > +
> > +module_init(simatic_ipc_wdt_init);
> > +module_exit(simatic_ipc_wdt_exit);
> > +
> > +MODULE_LICENSE("GPL");
> > +MODULE_ALIAS("platform:" KBUILD_MODNAME);
> > +MODULE_AUTHOR("Gerd Haeussler <gerd.haeussler.ext@siemens.com>");
> > --
> > 2.26.2
> >
> >  
>