RE: [PATCH V8 2/4] watchdog: imx_sc: Add i.MX system controller watchdog support
From: Anson Huang
Date: Wed Mar 20 2019 - 20:23:16 EST
Hi, Guenter
Best Regards!
Anson Huang
> -----Original Message-----
> From: Guenter Roeck [mailto:groeck7@xxxxxxxxx] On Behalf Of Guenter
> Roeck
> Sent: 2019年3月20日 21:44
> To: Anson Huang <anson.huang@xxxxxxx>
> Cc: wim@xxxxxxxxxxxxxxxxxx; robh+dt@xxxxxxxxxx; mark.rutland@xxxxxxx;
> shawnguo@xxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx;
> festevam@xxxxxxxxx; catalin.marinas@xxxxxxx; will.deacon@xxxxxxx;
> Aisheng Dong <aisheng.dong@xxxxxxx>; Daniel Baluta
> <daniel.baluta@xxxxxxx>; heiko@xxxxxxxxx; horms+renesas@xxxxxxxxxxxx;
> Andy Gross <andy.gross@xxxxxxxxxx>; maxime.ripard@xxxxxxxxxxx;
> olof@xxxxxxxxx; bjorn.andersson@xxxxxxxxxx; jagan@xxxxxxxxxxxxxxxxxxxx;
> enric.balletbo@xxxxxxxxxxxxx; ezequiel@xxxxxxxxxxxxx;
> stefan.wahren@xxxxxxxx; marc.w.gonzalez@xxxxxxx; linux-
> watchdog@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; dl-linux-imx
> <linux-imx@xxxxxxx>
> Subject: Re: [PATCH V8 2/4] watchdog: imx_sc: Add i.MX system controller
> watchdog support
>
> On Fri, Mar 15, 2019 at 06:17:25AM +0000, Anson Huang wrote:
> > i.MX8QXP is an ARMv8 SoC which has a Cortex-M4 system controller
> > inside, the system controller is in charge of controlling power, clock
> > and watchdog etc..
> >
> > This patch adds i.MX system controller watchdog driver support,
> > watchdog operation needs to be done in secure EL3 mode via
> > ARM-Trusted-Firmware, using SMC call, CPU will trap into
> > ARM-Trusted-Firmware and then it will request system controller to do
> > watchdog operation via IPC.
> >
> > Signed-off-by: Anson Huang <Anson.Huang@xxxxxxx>
>
> Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
>
> Waiting for bindings approval, though. Plus a minor comment below.
>
> Guenter
>
> > ---
> > Changes since V7:
> > - remove the dependence of IMX_SCU as it does NOT call SCU API
> directly;
> > - add more detail info into the help section of how this module works;
> > - add back device id table since now we have watchdog node in DT.
> > ---
> > drivers/watchdog/Kconfig | 16 ++++
> > drivers/watchdog/Makefile | 1 +
> > drivers/watchdog/imx_sc_wdt.c | 182
> > ++++++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 199 insertions(+)
> > create mode 100644 drivers/watchdog/imx_sc_wdt.c
> >
> > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index
> > 242eea8..44a3158 100644
> > --- a/drivers/watchdog/Kconfig
> > +++ b/drivers/watchdog/Kconfig
> > @@ -641,6 +641,22 @@ config IMX2_WDT
> > To compile this driver as a module, choose M here: the
> > module will be called imx2_wdt.
> >
> > +config IMX_SC_WDT
> > + tristate "IMX SC Watchdog"
> > + depends on HAVE_ARM_SMCCC
> > + select WATCHDOG_CORE
> > + help
> > + This is the driver for the system controller watchdog
> > + on the NXP i.MX SoCs with system controller inside, the
> > + watchdog driver will call ARM SMC API and trap into
> > + ARM-Trusted-Firmware for operations, ARM-Trusted-Firmware
> > + will request system controller to execute the operations.
> > + If you have one of these processors and wish to have
> > + watchdog support enabled, say Y, otherwise say N.
> > +
> > + To compile this driver as a module, choose M here: the
> > + module will be called imx_sc_wdt.
> > +
> > config UX500_WATCHDOG
> > tristate "ST-Ericsson Ux500 watchdog"
> > depends on MFD_DB8500_PRCMU
> > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> > index ba930e4..136d9f0 100644
> > --- a/drivers/watchdog/Makefile
> > +++ b/drivers/watchdog/Makefile
> > @@ -68,6 +68,7 @@ obj-$(CONFIG_NUC900_WATCHDOG) +=
> nuc900_wdt.o
> > obj-$(CONFIG_TS4800_WATCHDOG) += ts4800_wdt.o
> > obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
> > obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
> > +obj-$(CONFIG_IMX_SC_WDT) += imx_sc_wdt.o
> > obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
> > obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
> > obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o diff --git
> > a/drivers/watchdog/imx_sc_wdt.c b/drivers/watchdog/imx_sc_wdt.c new
> > file mode 100644 index 0000000..c8a087a
> > --- /dev/null
> > +++ b/drivers/watchdog/imx_sc_wdt.c
> > @@ -0,0 +1,182 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright 2018-2019 NXP.
> > + */
> > +
> > +#include <linux/arm-smccc.h>
> > +#include <linux/io.h>
> > +#include <linux/init.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/moduleparam.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/reboot.h>
> > +#include <linux/watchdog.h>
> > +
> > +#define DEFAULT_TIMEOUT 60
> > +/*
> > + * Software timer tick implemented in scfw side, support 10ms to
> > +0xffffffff ms
> > + * in theory, but for normal case, 1s~128s is enough, you can change
> > +this max
> > + * value in case it's not enough.
> > + */
> > +#define MAX_TIMEOUT 128
> > +
> > +#define IMX_SIP_TIMER 0xC2000002
> > +#define IMX_SIP_TIMER_START_WDOG 0x01
> > +#define IMX_SIP_TIMER_STOP_WDOG 0x02
> > +#define IMX_SIP_TIMER_SET_WDOG_ACT 0x03
> > +#define IMX_SIP_TIMER_PING_WDOG 0x04
> > +#define IMX_SIP_TIMER_SET_TIMEOUT_WDOG 0x05
> > +#define IMX_SIP_TIMER_GET_WDOG_STAT 0x06
> > +#define IMX_SIP_TIMER_SET_PRETIME_WDOG 0x07
> > +
> > +#define SC_TIMER_WDOG_ACTION_PARTITION 0
> > +
> > +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 unsigned int timeout = DEFAULT_TIMEOUT;
>
> I still don't understand why you explicitly disable configuring the watchdog
> timeout through devicetree (unless the user explicitly provides a timeout=0
> module parameter). Maybe add some comment if you send another version.
I thought this watchdog will be built as module anyway, and user can pass the timeout
parameter when insmod this module, so I just choose the way of getting it from module parameter.
I will add a comment if there is another version needed.
Thanks,
Anson.
>
> > +module_param(timeout, uint, 0000);
> > +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
> > + __MODULE_STRING(DEFAULT_TIMEOUT) ")");
> > +
> > +static int imx_sc_wdt_ping(struct watchdog_device *wdog) {
> > + struct arm_smccc_res res;
> > +
> > + arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_PING_WDOG,
> > + 0, 0, 0, 0, 0, 0, &res);
> > +
> > + return 0;
> > +}
> > +
> > +static int imx_sc_wdt_start(struct watchdog_device *wdog) {
> > + struct arm_smccc_res res;
> > +
> > + arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_START_WDOG,
> > + 0, 0, 0, 0, 0, 0, &res);
> > + if (res.a0)
> > + return -EACCES;
> > +
> > + arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_WDOG_ACT,
> > + SC_TIMER_WDOG_ACTION_PARTITION,
> > + 0, 0, 0, 0, 0, &res);
> > + return res.a0 ? -EACCES : 0;
> > +}
> > +
> > +static int imx_sc_wdt_stop(struct watchdog_device *wdog) {
> > + struct arm_smccc_res res;
> > +
> > + arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_STOP_WDOG,
> > + 0, 0, 0, 0, 0, 0, &res);
> > +
> > + return res.a0 ? -EACCES : 0;
> > +}
> > +
> > +static int imx_sc_wdt_set_timeout(struct watchdog_device *wdog,
> > + unsigned int timeout)
> > +{
> > + struct arm_smccc_res res;
> > +
> > + wdog->timeout = timeout;
> > + arm_smccc_smc(IMX_SIP_TIMER,
> IMX_SIP_TIMER_SET_TIMEOUT_WDOG,
> > + timeout * 1000, 0, 0, 0, 0, 0, &res);
> > +
> > + return res.a0 ? -EACCES : 0;
> > +}
> > +
> > +static const struct watchdog_ops imx_sc_wdt_ops = {
> > + .owner = THIS_MODULE,
> > + .start = imx_sc_wdt_start,
> > + .stop = imx_sc_wdt_stop,
> > + .ping = imx_sc_wdt_ping,
> > + .set_timeout = imx_sc_wdt_set_timeout, };
> > +
> > +static const struct watchdog_info imx_sc_wdt_info = {
> > + .identity = "i.MX SC watchdog timer",
> > + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
> > + WDIOF_MAGICCLOSE | WDIOF_PRETIMEOUT, };
> > +
> > +static int imx_sc_wdt_probe(struct platform_device *pdev) {
> > + struct watchdog_device *imx_sc_wdd;
> > + int ret;
> > +
> > + imx_sc_wdd = devm_kzalloc(&pdev->dev, sizeof(*imx_sc_wdd),
> GFP_KERNEL);
> > + if (!imx_sc_wdd)
> > + return -ENOMEM;
> > +
> > + platform_set_drvdata(pdev, imx_sc_wdd);
> > +
> > + imx_sc_wdd->info = &imx_sc_wdt_info;
> > + imx_sc_wdd->ops = &imx_sc_wdt_ops;
> > + imx_sc_wdd->min_timeout = 1;
> > + imx_sc_wdd->max_timeout = MAX_TIMEOUT;
> > + imx_sc_wdd->parent = &pdev->dev;
> > + imx_sc_wdd->timeout = DEFAULT_TIMEOUT;
> > +
> > + ret = watchdog_init_timeout(imx_sc_wdd, timeout, &pdev->dev);
> > + if (ret)
> > + dev_warn(&pdev->dev, "Failed to set timeout value, using
> > +default\n");
> > +
> > + watchdog_stop_on_reboot(imx_sc_wdd);
> > + watchdog_stop_on_unregister(imx_sc_wdd);
> > +
> > + ret = devm_watchdog_register_device(&pdev->dev, imx_sc_wdd);
> > + if (ret) {
> > + dev_err(&pdev->dev, "Failed to register watchdog device\n");
> > + return ret;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int __maybe_unused imx_sc_wdt_suspend(struct device *dev) {
> > + struct watchdog_device *imx_sc_wdd = dev_get_drvdata(dev);
> > +
> > + if (watchdog_active(imx_sc_wdd))
> > + imx_sc_wdt_stop(imx_sc_wdd);
> > +
> > + return 0;
> > +}
> > +
> > +static int __maybe_unused imx_sc_wdt_resume(struct device *dev) {
> > + struct watchdog_device *imx_sc_wdd = dev_get_drvdata(dev);
> > +
> > + if (watchdog_active(imx_sc_wdd))
> > + imx_sc_wdt_start(imx_sc_wdd);
> > +
> > + return 0;
> > +}
> > +
> > +static SIMPLE_DEV_PM_OPS(imx_sc_wdt_pm_ops,
> > + imx_sc_wdt_suspend, imx_sc_wdt_resume);
> > +
> > +static const struct of_device_id imx_sc_wdt_dt_ids[] = {
> > + { .compatible = "fsl,imx-sc-wdt", },
> > + { /* sentinel */ }
> > +};
> > +MODULE_DEVICE_TABLE(of, imx_sc_wdt_dt_ids);
> > +
> > +static struct platform_driver imx_sc_wdt_driver = {
> > + .probe = imx_sc_wdt_probe,
> > + .driver = {
> > + .name = "imx-sc-wdt",
> > + .of_match_table = imx_sc_wdt_dt_ids,
> > + .pm = &imx_sc_wdt_pm_ops,
> > + },
> > +};
> > +module_platform_driver(imx_sc_wdt_driver);
> > +
> > +MODULE_AUTHOR("Robin Gong <yibin.gong@xxxxxxx>");
> > +MODULE_DESCRIPTION("NXP i.MX system controller watchdog driver");
> > +MODULE_LICENSE("GPL v2");