Hi Guenter, Could you please share your comments on below limitations. Thanks Srinivas Neeli > -----Original Message----- > From: Srinivas Neeli <sneeli@xxxxxxxxxx> > Sent: Wednesday, September 29, 2021 12:32 PM > To: Guenter Roeck <linux@xxxxxxxxxxxx>; Shubhrajyoti Datta > <shubhraj@xxxxxxxxxx>; Srinivas Goud <sgoud@xxxxxxxxxx>; Michal Simek > <michals@xxxxxxxxxx> > Cc: wim@xxxxxxxxxxxxxxxxxx; linux-watchdog@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; git <git@xxxxxxxxxx> > Subject: RE: [PATCH 2/3] watchdog: xilinx_wwdt: Add Versal Window > watchdog mode > > Hi Guenter, > > I went through reference "rti_wdt.c" driver. It implemented Window > watchdog with few limitations. > Limitations: > --------------- > 1) Not able to configure Closed window and Open window separately. > Because of xilinx window watchdog supports separate configurable > closed and open windows. > 2) In case of rti driver, if any bad event(error event) occur due to any user > space event like ping then > the watchdog core bypassing the ping call. > But in case of xilinx watchdog there are separate register bits for counting > error events. > So if I implement driver in similar to rti-wdt.c driver, then we can not > be able read the error events from > the registers. > So is this ok because we are not notifying the errors to user. > > Thanks > Srinivas Neeli > > > -----Original Message----- > > From: Guenter Roeck <groeck7@xxxxxxxxx> On Behalf Of Guenter Roeck > > Sent: Wednesday, July 14, 2021 5:01 PM > > To: Srinivas Neeli <sneeli@xxxxxxxxxx>; Shubhrajyoti Datta > > <shubhraj@xxxxxxxxxx>; Srinivas Goud <sgoud@xxxxxxxxxx>; Michal Simek > > <michals@xxxxxxxxxx> > > Cc: wim@xxxxxxxxxxxxxxxxxx; linux-watchdog@xxxxxxxxxxxxxxx; linux- > > kernel@xxxxxxxxxxxxxxx; git <git@xxxxxxxxxx> > > Subject: Re: [PATCH 2/3] watchdog: xilinx_wwdt: Add Versal Window > > watchdog mode > > > > On 7/13/21 10:29 PM, Srinivas Neeli wrote: > > > Hi Guenter, > > > > > > If you are fine with my justification, I will send v2 with update code. > > > > > > > We have at least one more watchdog driver with open/closed window > > concepts. > > This is not a "pretimeout". Please see drivers/watchdog/rti_wdt.c for > > an example on how to handle this; essentially you have to set > > min_hw_heartbeat_ms to the value of the closed window timeout. The > > watchdog core then handles the mechanics. > > > > You can not use "pretimeout" to set the "closed" window size; this is > > an ABI abuse. There is no standard ABI for this, so if you want to > > have it configurable it would have to be a module parameter. > > > > Guenter > > > > > Thanks > > > Srinivas Neeli. > > > > > > *From:* Srinivas Neeli <sneeli@xxxxxxxxxx> > > > *Sent:* Wednesday, June 9, 2021 12:57 PM > > > *To:* Guenter Roeck <linux@xxxxxxxxxxxx>; Shubhrajyoti Datta > > > <shubhraj@xxxxxxxxxx>; Srinivas Goud <sgoud@xxxxxxxxxx>; Michal > > > Simek <michals@xxxxxxxxxx> > > > *Cc:* wim@xxxxxxxxxxxxxxxxxx; linux-watchdog@xxxxxxxxxxxxxxx; > > > linux-kernel@xxxxxxxxxxxxxxx; git <git@xxxxxxxxxx> > > > *Subject:* RE: [PATCH 2/3] watchdog: xilinx_wwdt: Add Versal Window > > > watchdog mode > > > > > > Hi Guenter Roeck, > > > > > > Thanks for review. > > > > > > Versal platform contain System watchdog Timer. It supports two > > > functions, Those are > > > > > > 1) Generic watchdog mode > > > > > > 2) Window watchdog mode > > > > > > Right now we are implementing window watchdog timer functionality in > > driver. > > > > > > Features of Window watchdog mode: > > > > > > - The timer contains two configurable windows( closed and open). > > > > > > - The timer has to restart only in open window. > > > > > > - If software tries to restart out side of open window it will > > > generate a > > reset. > > > > > > We have a requirement for window watchdog driver, So I implemented > > window watchdog in two scenarios. > > > > > > 1) With Pre-timeout > > > > > > 2) With without Pre-timeout > > > > > > *Scenario 1:* > > > > > > With pre-timeout: > > > > > > Here we will get two window concept. > > > > > > 1) closed window > > > > > > 2) Open window > > > > > > start to pre-timeout, we are calling "*closed*" window. > > > > > > From pre-timeout to timeout we are calling “*Open*” window. > > > > > > *Operations:* > > > > > > start > > > > > > keep alive(only in open window, closed window we are ignoring) > > > > > > stop > > > > > > we don't have permission to refresh/restart our timer in closed > > > window, So > > ignoring the keepalive. > > > > > > Adjusted code to generate interrupt after completion of closed window. > > once we cross the closed window we can restart our time anytime. > > > > > > Once we reaches to timeout , will get reset signal. > > > > > > *Advantage:* > > > > > > After getting pre-timeout notification we can reset our timer or can > > > collect > > our log. > > > > > > once we get interrupt we can conclude our task is not working as > expected. > > > > > > So we can takecare of our tasks. > > > > > > *Scenario 2:* > > > > > > with out pre-timeout: > > > > > > It will work like general watchdog timer. > > > > > > we can run keepalive anytime(as there is no closed window, only open > > window present). > > > > > > Once we reaches to time out, will get reset. > > > > > > *Operations:* > > > > > > start > > > > > > keep alive > > > > > > stop > > > > > > For more details: > > > > > > https://www.xilinx.com/support/documentation/architecture- > > manuals/am01 > > > 1-versal-acap-trm.pdf > > > <https://www.xilinx.com/support/documentation/architecture- > > manuals/am0 > > > 11-versal-acap-trm.pdf> > > > > > > major comments will update in V2. > > > > > > > -----Original Message----- > > > > > > > From: Guenter Roeck <groeck7@xxxxxxxxx > > <mailto:groeck7@xxxxxxxxx>> > > > On Behalf Of Guenter Roeck > > > > > > > Sent: Thursday, May 27, 2021 8:09 PM > > > > > > > To: Srinivas Neeli <sneeli@xxxxxxxxxx > > > <mailto:sneeli@xxxxxxxxxx>>; Shubhrajyoti Datta > > > > > > > <shubhraj@xxxxxxxxxx <mailto:shubhraj@xxxxxxxxxx>>; Srinivas Goud > > > <sgoud@xxxxxxxxxx <mailto:sgoud@xxxxxxxxxx>>; Michal Simek > > > > > > > <michals@xxxxxxxxxx <mailto:michals@xxxxxxxxxx>> > > > > > > > Cc: wim@xxxxxxxxxxxxxxxxxx <mailto:wim@xxxxxxxxxxxxxxxxxx>; > > > linux-watchdog@xxxxxxxxxxxxxxx > > > <mailto:linux-watchdog@xxxxxxxxxxxxxxx>; linux- > > > > > > > kernel@xxxxxxxxxxxxxxx <mailto:kernel@xxxxxxxxxxxxxxx>; git > > > <git@xxxxxxxxxx <mailto:git@xxxxxxxxxx>> > > > > > > > Subject: Re: [PATCH 2/3] watchdog: xilinx_wwdt: Add Versal Window > > > > > > > watchdog mode > > > > > > > > > > > > > > The subject is confusing. This patch does not add "Versal Window > > > watchdog > > > > > > > mode", it adds a driver which supports the Versal Window watchdog. > > > The > > > > > > > subject should be something like "watchdog: Add Versal Window > > > watchdog > > > > > > > driver". > > > > > > > > > > > > > > On 5/27/21 2:57 AM, Srinivas Neeli wrote: > > > > > > > > Versal watchdog driver uses Window watchdog mode. Window > > watchdog > > > > > > > > timer(WWDT) contains closed(first) and open(second) window with > > > > > > > > 32 bit width. WWDT will generate an interrupt after the first > > > window > > > > > > > > timeout and reset signal after the second window timeout. > > > Timeout and > > > > > > > > Pre-timeout configuration, Stop and Refresh trigger only in > > > open > > > > > > > > window. > > > > > > > > > > > > > > Does that mean that userspace can not send a keepalive before the > > > > > > > pretimeout expires ? That is not how this is supposed to work. If > > > that is the > > > > > > > case, this is not a pretimeout. Pretimeout is supposed to be used > > > for > > > > > > > emergency handling, such as triggering a crash dump. The above > > > description > > > > > > > as well as the code suggests that an interrupt is all but mandatory. > > > > > > > > > > > > > > Assuming that is all the case, ie that keepalive is only possible > > > after the > > > > > > > interrupt was received, and that timeout updates are also only > > > possible after > > > > > > > an interrupt was received, one possible handling would to record > > > that a > > > > > > > keepalive was received, and to record that a request to update > > > the timeout > > > > > > > was received if that happens while the window is closed. Then, > > > when the > > > > > > > interrupt is received, those actions can be applied. Otherwise, > > > if there was > > > > > > > no keepalive request prior to the interrupt, the interrupt > > > handler would call > > > > > > > watchdog_notify_pretimeout(). > > > > > > > > > > > > > > Of course, this is all just guesswork. > > > > > > > > > > > > > > More comments below. > > > > > > > > > > > > > > Guenter > > > > > > > > > > > > > > > > > > > > > > > Signed-off-by: Srinivas Neeli <srinivas.neeli@xxxxxxxxxx > > > <mailto:srinivas.neeli@xxxxxxxxxx>> > > > > > > > > --- > > > > > > > > drivers/watchdog/Kconfig | 16 ++ > > > > > > > > drivers/watchdog/Makefile | 1 + > > > > > > > > drivers/watchdog/xilinx_wwdt.c | 382 > > > > > > > +++++++++++++++++++++++++++++++++ > > > > > > > > 3 files changed, 399 insertions(+) > > > > > > > > create mode 100644 drivers/watchdog/xilinx_wwdt.c > > > > > > > > > > > > > > > > diff --git a/drivers/watchdog/Kconfig > > > b/drivers/watchdog/Kconfig index > > > > > > > > 355100dad60a..2ed17f278783 100644 > > > > > > > > --- a/drivers/watchdog/Kconfig > > > > > > > > +++ b/drivers/watchdog/Kconfig > > > > > > > > @@ -307,6 +307,22 @@ config XILINX_WATCHDOG > > > > > > > > To compile this driver as a module, choose M here: > > > the > > > > > > > > module will be called of_xilinx_wdt. > > > > > > > > > > > > > > > > +config XILINX_WINDOW_WATCHDOG > > > > > > > > + tristate "Xilinx Window Watchdog timer" > > > > > > > > + depends on HAS_IOMEM > > > > > > > > + select WATCHDOG_CORE > > > > > > > > + help > > > > > > > > + Window Watchdog driver for the versal_wwdt ip core. > > > > > > > > + Window watchdog timer(WWDT) contains closed(first) and > > > > > > > > + open(second) window with 32 bit width. WWDT will > > > generate > > > > > > > > + an interrupt after the first window timeout and reset > > > > > > > > + signal after the second window timeout. Timeout and > > > > > > > > + Pre-timeout configuration, Stop and Refresh trigger > > > > > > > > + only in open window. > > > > > > > > + > > > > > > > > + To compile this driver as a module, choose M here: the > > > > > > > > + module will be called xilinx_wwdt. > > > > > > > > + > > > > > > > > config ZIIRAVE_WATCHDOG > > > > > > > > tristate "Zodiac RAVE Watchdog Timer" > > > > > > > > depends on I2C > > > > > > > > diff --git a/drivers/watchdog/Makefile > > > b/drivers/watchdog/Makefile > > > > > > > > index a7eade8b4d45..97d10c3d39c7 100644 > > > > > > > > --- a/drivers/watchdog/Makefile > > > > > > > > +++ b/drivers/watchdog/Makefile > > > > > > > > @@ -148,6 +148,7 @@ obj-$(CONFIG_M54xx_WATCHDOG) += > > > > > > > m54xx_wdt.o > > > > > > > > > > > > > > > > # MicroBlaze Architecture > > > > > > > > obj-$(CONFIG_XILINX_WATCHDOG) += of_xilinx_wdt.o > > > > > > > > +obj-$(CONFIG_XILINX_WINDOW_WATCHDOG) += xilinx_wwdt.o > > > > > > > > > > > > > > > > # MIPS Architecture > > > > > > > > obj-$(CONFIG_ATH79_WDT) += ath79_wdt.o diff --git > > > > > > > > a/drivers/watchdog/xilinx_wwdt.c > > > b/drivers/watchdog/xilinx_wwdt.c new > > > > > > > > file mode 100644 index 000000000000..8fa2cb2225e8 > > > > > > > > --- /dev/null > > > > > > > > +++ b/drivers/watchdog/xilinx_wwdt.c > > > > > > > > @@ -0,0 +1,382 @@ > > > > > > > > +// SPDX-License-Identifier: GPL-2.0 > > > > > > > > +/* > > > > > > > > + * Window Watchdog Device Driver for Xilinx Versal WWDT > > > > > > > > + * > > > > > > > > + * (C) Copyright 2021 Xilinx, Inc. > > > > > > > > + */ > > > > > > > > + > > > > > > > > +#include <linux/clk.h> > > > > > > > > +#include <linux/interrupt.h> > > > > > > > > +#include <linux/io.h> > > > > > > > > +#include <linux/ioport.h> > > > > > > > > +#include <linux/of_device.h> > > > > > > > > +#include <linux/of_address.h> > > > > > > > > +#include <linux/module.h> > > > > > > > > +#include <linux/watchdog.h> > > > > > > > > + > > > > > > > > +#define XWWDT_DEFAULT_TIMEOUT 40 > > > > > > > > +#define XWWDT_MIN_TIMEOUT 1 > > > > > > > > +#define XWWDT_MAX_TIMEOUT 42 > > > > > > > > + > > > > > > > > +/* Register offsets for the WWdt device */ > > > > > > > > +#define XWWDT_MWR_OFFSET 0x00 > > > > > > > > +#define XWWDT_ESR_OFFSET 0x04 > > > > > > > > +#define XWWDT_FCR_OFFSET 0x08 > > > > > > > > +#define XWWDT_FWR_OFFSET 0x0c > > > > > > > > +#define XWWDT_SWR_OFFSET 0x10 > > > > > > > > + > > > > > > > > +/* Master Write Control Register Masks */ > > > > > > > > +#define XWWDT_MWR_MASK BIT(0) > > > > > > > > + > > > > > > > > +/* Enable and Status Register Masks */ > > > > > > > > +#define XWWDT_ESR_WINT_MASK BIT(16) > > > > > > > > +#define XWWDT_ESR_WSW_MASK BIT(8) > > > > > > > > +#define XWWDT_ESR_WEN_MASK BIT(0) > > > > > > > > + > > > > > > > > +/* Function control Register Masks */ > > > > > > > > +#define XWWDT_SBC_MASK 0xFF00 > > > > > > > > +#define XWWDT_SBC_SHIFT 16 > > > > > > > > +#define XWWDT_BSS_MASK 0xC0 > > > > > > > > + > > > > > > > > +static int wwdt_timeout; > > > > > > > > + > > > > > > > > +module_param(wwdt_timeout, int, 0644); > > > > > > > MODULE_PARM_DESC(wwdt_timeout, > > > > > > > > + "Watchdog time in seconds. (default=" > > > > > > > > + __MODULE_STRING(XWWDT_DEFAULT_TIMEOUT) > > > ")"); > > > > > > > > + > > > > > > > > +struct xwwdt_device { > > > > > > > > + void __iomem *base; > > > > > > > > + spinlock_t spinlock; /* spinlock for register handling > > > */ > > > > > > > > + struct watchdog_device xilinx_wwdt_wdd; > > > > > > > > + struct clk *clk; > > > > > > > > + int irq; > > > > > > > > +}; > > > > > > > > + > > > > > > > > +static int is_wwdt_in_closed_window(struct watchdog_device > > > *wdd) > > > > > > > > > > > > > > should return bool > > > > > > Will update in V2. > > > > > > > > > > > > > > > +{ > > > > > > > > + u32 control_status_reg; > > > > > > > > + struct xwwdt_device *xdev = watchdog_get_drvdata(wdd); > > > > > > > > + > > > > > > > > + spin_lock(&xdev->spinlock); > > > > > > > > + control_status_reg = ioread32(xdev->base + > > > XWWDT_ESR_OFFSET); > > > > > > > > + spin_unlock(&xdev->spinlock); > > > > > > > > + if (control_status_reg & XWWDT_ESR_WEN_MASK) > > > > > > > > + if (!(control_status_reg & > > > XWWDT_ESR_WSW_MASK)) > > > > > > > > + return 0; > > > > > > > > + > > > > > > > > + return 1; > > > > > > > > > > > > > > Can be written as expresion without if statement > > > > > > Will update in V2 > > > > > > > > > > > > > > > +} > > > > > > > > + > > > > > > > > +static int xilinx_wwdt_start(struct watchdog_device *wdd) { > > > > > > > > + struct xwwdt_device *xdev = watchdog_get_drvdata(wdd); > > > > > > > > + struct watchdog_device *xilinx_wwdt_wdd = &xdev- > > > > > > > >xilinx_wwdt_wdd; > > > > > > > > + u64 time_out, pre_timeout, count; > > > > > > > > + u32 control_status_reg, fcr; > > > > > > > > + int ret; > > > > > > > > + > > > > > > > > + count = clk_get_rate(xdev->clk); > > > > > > > > + if (!count) > > > > > > > > + return -EINVAL; > > > > > > > > + > > > > > > > Is there a reason to believe that the clock rate can change ? > > > > > > > If not I would suggest to read it once and store it in struct > xwwdt_device. > > > > > > Will update in V2. > > > > > > > > > > > > > > > + /* Calculate timeout count */ > > > > > > > > + pre_timeout = count * wdd->pretimeout; > > > > > > > > + time_out = count * wdd->timeout; > > > > > > > > + if (!watchdog_active(xilinx_wwdt_wdd)) { > > > > > > > > + ret = clk_enable(xdev->clk); > > > > > > > > > > > > > > This is at the very least confusing. > > > > > > > The last action in the probe function is to call > > > clk_disable_unprepare(), > > > > > > > meaning the clock should not be prepared here. How can it be > > > enabled > > > > > > > without being prepared ? > > > > > > Will update in V2 > > > > > > > > > > > > > > > + if (ret) { > > > > > > > > + dev_err(wdd->parent, > > > "Failed to enable clock\n"); > > > > > > > > + return ret; > > > > > > > > + } > > > > > > > > + } > > > > > > > > + > > > > > > > I think it would be better to separate the functions to > > > start/stop the clock > > > > > > > from the function to update/enable the watchdog. The use of > > > > > > > watchdog_active() combined with > > > > > > > clk_enable/clk_disable/clk_prepare_enable/clk_disable_unprepare > > > > > > > is confusing and makes it all but impossible to review the driver. > > > > > > > > > > > > > > > + spin_lock(&xdev->spinlock); > > > > > > > > + iowrite32(XWWDT_MWR_MASK, xdev->base + > > > > > > > XWWDT_MWR_OFFSET); > > > > > > > > + iowrite32(~(u32)XWWDT_ESR_WEN_MASK, > > > > > > > > + xdev->base + XWWDT_ESR_OFFSET); > > > > > > > > + > > > > > > > > + if (pre_timeout) { > > > > > > > > + iowrite32((u32)(time_out - pre_timeout), > > > > > > > > + xdev->base + > > > XWWDT_FWR_OFFSET); > > > > > > > > + iowrite32((u32)pre_timeout, xdev->base + > > > > > > > XWWDT_SWR_OFFSET); > > > > > > > > + fcr = ioread32(xdev->base + > > > XWWDT_SWR_OFFSET); > > > > > > > > + fcr = (fcr >> XWWDT_SBC_SHIFT) & > > > XWWDT_SBC_MASK; > > > > > > > > + fcr = fcr | XWWDT_BSS_MASK; > > > > > > > > + iowrite32(fcr, xdev->base + > > > XWWDT_FCR_OFFSET); > > > > > > > > + } else { > > > > > > > > + iowrite32((u32)pre_timeout, > > > > > > > > + xdev->base + > > > XWWDT_FWR_OFFSET); > > > > > > > > + iowrite32((u32)time_out, xdev->base + > > > > > > > XWWDT_SWR_OFFSET); > > > > > > > > + iowrite32(0x0, xdev->base + > > > XWWDT_FCR_OFFSET); > > > > > > > > + } > > > > > > > > + > > > > > > > > + /* Enable the window watchdog timer */ > > > > > > > > + control_status_reg = ioread32(xdev->base + > > > XWWDT_ESR_OFFSET); > > > > > > > > + control_status_reg |= XWWDT_ESR_WEN_MASK; > > > > > > > > + iowrite32(control_status_reg, xdev->base + > > > XWWDT_ESR_OFFSET); > > > > > > > > + > > > > > > > > + spin_unlock(&xdev->spinlock); > > > > > > > > + > > > > > > > > + dev_dbg(xilinx_wwdt_wdd->parent, "Watchdog Started!\n"); > > > > > > > > + > > > > > > > > + return 0; > > > > > > > > +} > > > > > > > > + > > > > > > > > +static int xilinx_wwdt_stop(struct watchdog_device *wdd) { > > > > > > > > + struct xwwdt_device *xdev = watchdog_get_drvdata(wdd); > > > > > > > > + struct watchdog_device *xilinx_wwdt_wdd = &xdev- > > > > > > > >xilinx_wwdt_wdd; > > > > > > > > + > > > > > > > > + if (!is_wwdt_in_closed_window(wdd)) { > > > > > > > > + dev_warn(xilinx_wwdt_wdd->parent, "timer > > > in closed > > > > > > > window"); > > > > > > > > + return -EINVAL; > > > > > > > > + } > > > > > > > > + > > > > > > > > + spin_lock(&xdev->spinlock); > > > > > > > > + > > > > > > > > + iowrite32(XWWDT_MWR_MASK, xdev->base + > > > > > > > XWWDT_MWR_OFFSET); > > > > > > > > + /* Disable the Window watchdog timer */ > > > > > > > > + iowrite32(~(u32)XWWDT_ESR_WEN_MASK, > > > > > > > > + xdev->base + XWWDT_ESR_OFFSET); > > > > > > > > + > > > > > > > > + spin_unlock(&xdev->spinlock); > > > > > > > > + > > > > > > > > + if (watchdog_active(xilinx_wwdt_wdd)) > > > > > > > > + clk_disable(xdev->clk); > > > > > > > > + > > > > > > > > > > > > > > The stop function won't be called if the watchdog is not running, > > > ie if > > > > > > > watchdog_active() returns false. > > > > > > > I don't undeerstand the logic of clock handling in this driver. > > > > > > > More on that below. > > > > > > > > > > > > > > > + dev_dbg(xilinx_wwdt_wdd->parent, "Watchdog Stopped!\n"); > > > > > > > > + > > > > > > > > + return 0; > > > > > > > > +} > > > > > > > > + > > > > > > > > +static int xilinx_wwdt_keepalive(struct watchdog_device *wdd) > > > { > > > > > > > > + u32 control_status_reg; > > > > > > > > + struct xwwdt_device *xdev = watchdog_get_drvdata(wdd); > > > > > > > > + > > > > > > > > + /* Refresh in open window is ignored */ > > > > > > > > + if (!is_wwdt_in_closed_window(wdd)) > > > > > > > > + return 0; > > > > > > > > + > > > > > > > This is dangerous. There is no reason for userspace to adhere to > > > these > > > > > > > restrictions. > > > > > > > > > > > > > > > + spin_lock(&xdev->spinlock); > > > > > > > > + > > > > > > > > + iowrite32(XWWDT_MWR_MASK, xdev->base + > > > > > > > XWWDT_MWR_OFFSET); > > > > > > > > + control_status_reg = ioread32(xdev->base + > > > XWWDT_ESR_OFFSET); > > > > > > > > + control_status_reg |= XWWDT_ESR_WINT_MASK; > > > > > > > > + control_status_reg &= ~XWWDT_ESR_WSW_MASK; > > > > > > > > + iowrite32(control_status_reg, xdev->base + > > > XWWDT_ESR_OFFSET); > > > > > > > > + control_status_reg = ioread32(xdev->base + > > > XWWDT_ESR_OFFSET); > > > > > > > > + control_status_reg |= XWWDT_ESR_WSW_MASK; > > > > > > > > + iowrite32(control_status_reg, xdev->base + > > > XWWDT_ESR_OFFSET); > > > > > > > > + > > > > > > > > + spin_unlock(&xdev->spinlock); > > > > > > > > + > > > > > > > > + return 0; > > > > > > > > +} > > > > > > > > + > > > > > > > > +static int xilinx_wwdt_set_timeout(struct watchdog_device > > > *wdd, > > > > > > > > + > > > unsigned int new_time) > > > > > > > > +{ > > > > > > > > + u32 ret = 0; > > > > > > > > + struct xwwdt_device *xdev = watchdog_get_drvdata(wdd); > > > > > > > > + struct watchdog_device *xilinx_wwdt_wdd = &xdev- > > > > > > > >xilinx_wwdt_wdd; > > > > > > > > + > > > > > > > > + if (!is_wwdt_in_closed_window(wdd)) { > > > > > > > > + dev_warn(xilinx_wwdt_wdd->parent, "timer > > > in closed > > > > > > > window"); > > > > > > > > + return -EINVAL; > > > > > > > > + } > > > > > > > > + > > > > > > > > > > > > > > So userspace can clog the log by continuously trying to set the timeout > ? > > > > > > > > > > > > > > Also, again, this is dangerous. Userspace does not know the window > size. > > > > > > user can configure window size. > > > > > > > > > > > > > > > > > > > > > > + if (new_time < XWWDT_MIN_TIMEOUT || > > > > > > > > + new_time > XWWDT_MAX_TIMEOUT) { > > > > > > > > + dev_warn(xilinx_wwdt_wdd->parent, > > > > > > > > + "timeout value must be > > > %d<=x<=%d, using %d\n", > > > > > > > > + XWWDT_MIN_TIMEOUT, > > > > > > > > + XWWDT_MAX_TIMEOUT, > > > new_time); > > > > > > > > + return -EINVAL; > > > > > > > > + } > > > > > > > > > > > > > > This is handled by the watchdog core. > > > > > > > > > > > > > > > + > > > > > > > > + wdd->timeout = new_time; > > > > > > > > + wdd->pretimeout = 0; > > > > > > > > + > > > > > > > > + if (watchdog_active(xilinx_wwdt_wdd)) { > > > > > > > > + ret = xilinx_wwdt_start(wdd); > > > > > > > > + if (ret) > > > > > > > > + > > > dev_dbg(xilinx_wwdt_wdd->parent, "timer start > > > > > > > failed"); > > > > > > > > + } > > > > > > > > + > > > > > > > > + return ret; > > > > > > > > +} > > > > > > > > + > > > > > > > > +static int xilinx_wwdt_set_pretimeout(struct watchdog_device > > > *wdd, > > > > > > > > + > > > u32 > > > new_pretimeout) > > > > > > > > +{ > > > > > > > > + u32 ret = 0; > > > > > > > > + struct xwwdt_device *xdev = watchdog_get_drvdata(wdd); > > > > > > > > + struct watchdog_device *xilinx_wwdt_wdd = &xdev- > > > > > > > >xilinx_wwdt_wdd; > > > > > > > > + > > > > > > > > + if (!is_wwdt_in_closed_window(wdd)) { > > > > > > > > + dev_warn(xilinx_wwdt_wdd->parent, "timer > > > in closed > > > > > > > window"); > > > > > > > > + return -EINVAL; > > > > > > > > + } > > > > > > > > > > > > > > This restriction is not only dangerous but confusing, and simply > > unacceptable. > > > > > > > Userspace will get -EINVAL with no idea what is wrong. > > > > > > > A watchdog daemon will bail out for no good reason. > > > > > > > > > > > > > > > + > > > > > > > > + if (new_pretimeout < wdd->min_timeout || > > > > > > > > + new_pretimeout >= wdd->timeout) > > > > > > > > + return -EINVAL; > > > > > > > > + > > > > > > > This is handled by the watchdog core. > > > > > > > > > > > > > > > + wdd->pretimeout = new_pretimeout; > > > > > > > > + > > > > > > > > + if (watchdog_active(xilinx_wwdt_wdd)) { > > > > > > > > + ret = xilinx_wwdt_start(wdd); > > > > > > > > + if (ret) > > > > > > > > + > > > dev_dbg(xilinx_wwdt_wdd->parent, "timer start > > > > > > > failed"); > > > > > > > > + } > > > > > > > > + > > > > > > > > + return ret; > > > > > > > > +} > > > > > > > > + > > > > > > > > +static void xwwdt_clk_disable_unprepare(void *data) { > > > > > > > > + clk_disable_unprepare(data); > > > > > > > > +} > > > > > > > > + > > > > > > > > +static irqreturn_t xilinx_wwdt_isr(int irq, void *wdog_arg) { > > > > > > > > + struct xwwdt_device *xdev = wdog_arg; > > > > > > > > + > > > > > > > > + watchdog_notify_pretimeout(&xdev->xilinx_wwdt_wdd); > > > > > > > > + > > > > > > > > + return IRQ_HANDLED; > > > > > > > > +} > > > > > > > > + > > > > > > > > +static const struct watchdog_info xilinx_wwdt_ident = { > > > > > > > > + .options = WDIOF_MAGICCLOSE | > > > > > > > > + WDIOF_KEEPALIVEPING | > > > > > > > > + WDIOF_SETTIMEOUT, > > > > > > > > + .firmware_version = 1, > > > > > > > > + .identity = "xlnx_window watchdog", > > > > > > > > +}; > > > > > > > > + > > > > > > > > +static const struct watchdog_info xilinx_wwdt_pretimeout_ident > > > = { > > > > > > > > + .options = WDIOF_MAGICCLOSE | > > > > > > > > + WDIOF_KEEPALIVEPING | > > > > > > > > + WDIOF_PRETIMEOUT | > > > > > > > > + WDIOF_SETTIMEOUT, > > > > > > > > + .firmware_version = 1, > > > > > > > > + .identity = "xlnx_window watchdog", > > > > > > > > +}; > > > > > > > > + > > > > > > > > +static const struct watchdog_ops xilinx_wwdt_ops = { > > > > > > > > + .owner = THIS_MODULE, > > > > > > > > + .start = xilinx_wwdt_start, > > > > > > > > + .stop = xilinx_wwdt_stop, > > > > > > > > + .ping = xilinx_wwdt_keepalive, > > > > > > > > + .set_timeout = xilinx_wwdt_set_timeout, > > > > > > > > + .set_pretimeout = xilinx_wwdt_set_pretimeout, }; > > > > > > > > + > > > > > > > > +static int xwwdt_probe(struct platform_device *pdev) { > > > > > > > > + struct device *dev = &pdev->dev; > > > > > > > > + struct watchdog_device *xilinx_wwdt_wdd; > > > > > > > > + struct xwwdt_device *xdev; > > > > > > > > + u32 pre_timeout = 0; > > > > > > > > + int ret; > > > > > > > > + > > > > > > > > + xdev = devm_kzalloc(dev, sizeof(*xdev), GFP_KERNEL); > > > > > > > > + if (!xdev) > > > > > > > > + return -ENOMEM; > > > > > > > > + > > > > > > > > + xilinx_wwdt_wdd = &xdev->xilinx_wwdt_wdd; > > > > > > > > + xilinx_wwdt_wdd->info = &xilinx_wwdt_ident; > > > > > > > > + xilinx_wwdt_wdd->ops = &xilinx_wwdt_ops; > > > > > > > > + xilinx_wwdt_wdd->parent = dev; > > > > > > > > + > > > > > > > > + xdev->base = devm_platform_ioremap_resource(pdev, 0); > > > > > > > > + if (IS_ERR(xdev->base)) > > > > > > > > + return PTR_ERR(xdev->base); > > > > > > > > + > > > > > > > > + ret = of_property_read_u32(dev->of_node, > > > "pretimeout-sec", > > > > > > > > + > > > &pre_timeout); > > > > > > > > + if (ret) > > > > > > > > + dev_dbg(dev, > > > > > > > > + "Parameter > > > \"pretimeout-sec\" not found\n"); > > > > > > > > + > > > > > > > > + xdev->clk = devm_clk_get(dev, NULL); > > > > > > > > + if (IS_ERR(xdev->clk)) > > > > > > > > + return PTR_ERR(xdev->clk); > > > > > > > > + > > > > > > > > + ret = clk_get_rate(xdev->clk); > > > > > > > > + if (!ret) > > > > > > > > + return -EINVAL; > > > > > > > > + > > > > > > > > + ret = clk_prepare_enable(xdev->clk); > > > > > > > > + if (ret) { > > > > > > > > + dev_err(dev, "unable to enable > > > clock\n"); > > > > > > > > + return ret; > > > > > > > > + } > > > > > > > > + ret = devm_add_action_or_reset(dev, > > > > > > > xwwdt_clk_disable_unprepare, > > > > > > > > + > > > xdev->clk); > > > > > > > > + if (ret) > > > > > > > > + goto err_clk_disable; > > > > > > > > + > > > > > > > > > > > > > > Seems pointless. What happens when you unload the driver ? > > > > > > > > > > > > > > > + xilinx_wwdt_wdd->pretimeout = pre_timeout; > > > > > > > > + xilinx_wwdt_wdd->timeout = XWWDT_DEFAULT_TIMEOUT; > > > > > > > > + xilinx_wwdt_wdd->min_timeout = XWWDT_MIN_TIMEOUT; > > > > > > > > + xilinx_wwdt_wdd->max_timeout = XWWDT_MAX_TIMEOUT; > > > > > > > > + > > > > > > > > + xdev->irq = platform_get_irq_byname(pdev, "wdt"); > > > > > > > > + if (xdev->irq < 0) { > > > > > > > > + ret = xdev->irq; > > > > > > > > + goto err_clk_disable; > > > > > > > > + } > > > > > > > > + > > > > > > > > + if (!devm_request_irq(dev, xdev->irq, xilinx_wwdt_isr, > > > > > > > > + 0, dev_name(dev), > > > xdev)) { > > > > > > > > + xilinx_wwdt_wdd->info = > > > &xilinx_wwdt_pretimeout_ident; > > > > > > > > + } > > > > > > > > + > > > > > > > > + ret = watchdog_init_timeout(xilinx_wwdt_wdd, > > > > > > > > + > > > wwdt_timeout, &pdev->dev); > > > > > > > > + if (ret) > > > > > > > > + dev_info(&pdev->dev, "Configured default > > > timeout > > > > > > > value\n"); > > > > > > > > + > > > > > > > > + spin_lock_init(&xdev->spinlock); > > > > > > > > + watchdog_set_drvdata(xilinx_wwdt_wdd, xdev); > > > > > > > > + > > > > > > > > + ret = devm_watchdog_register_device(dev, > > > xilinx_wwdt_wdd); > > > > > > > > + if (ret) > > > > > > > > + goto err_clk_disable; > > > > > > > > + > > > > > > > At this point the watchdog is fully instantiated, and userspace > > > may have > > > > > > > enabled it. > > > > > > > > > > > > > > > + clk_disable_unprepare(xdev->clk); > > > > > > > > + > > > > > > > And now its clock is getting stopped. Actually, it is getting unprepared. > > > > > > > Does this even work ? > > > > > > > > > > > > > > > + dev_info(dev, "Xilinx Window Watchdog Timer with timeout > > > %ds\n", > > > > > > > > + xilinx_wwdt_wdd->timeout); > > > > > > > > + > > > > > > > > + return 0; > > > > > > > > + > > > > > > > > +err_clk_disable: > > > > > > > > + clk_disable_unprepare(xdev->clk); > > > > > > > > > > > > > > devm_add_action_or_reset() already handles this. > > > > > > > > > > > > > > > + return ret; > > > > > > > > +} > > > > > > > > + > > > > > > > > +/* Mat for of_platform binding */ > > > > > > > > +static const struct of_device_id xwwdt_of_match[] = { > > > > > > > > + { .compatible = "xlnx,versal-wwdt-1.0", }, > > > > > > > > + {}, > > > > > > > > +}; > > > > > > > > +MODULE_DEVICE_TABLE(of, xwwdt_of_match); > > > > > > > > + > > > > > > > > +static struct platform_driver xwwdt_driver = { > > > > > > > > + .probe = xwwdt_probe, > > > > > > > > + .driver = { > > > > > > > > + .name = "Xilinx Window Watchdog", > > > > > > > > + .of_match_table = xwwdt_of_match, > > > > > > > > + }, > > > > > > > > +}; > > > > > > > > + > > > > > > > > +module_platform_driver(xwwdt_driver); > > > > > > > > + > > > > > > > > +MODULE_AUTHOR("Neeli Srinivas <sneeli@xxxxxxxxxx > > > <mailto:sneeli@xxxxxxxxxx>>"); > > > > > > > > +MODULE_DESCRIPTION("Xilinx Window Watchdog driver"); > > > > > > > > +MODULE_LICENSE("GPL"); > > > > > > > > > > > > > > Thanks > > > > > > Srinivas Neeli. > > >
