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Message-ID: <B256D81BAE5131468A838E5D7A243641C9F87788@penmbx01>
Date: Thu, 6 Aug 2015 10:22:45 +0000
From: "Yang, Wenyou" <Wenyou.Yang@...el.com>
To: Guenter Roeck <linux@...ck-us.net>,
"wim@...ana.be" <wim@...ana.be>,
"robh+dt@...nel.org" <robh+dt@...nel.org>,
"pawel.moll@....com" <pawel.moll@....com>,
"mark.rutland@....com" <mark.rutland@....com>,
"ijc+devicetree@...lion.org.uk" <ijc+devicetree@...lion.org.uk>,
"galak@...eaurora.org" <galak@...eaurora.org>
CC: "sylvain.rochet@...secur.com" <sylvain.rochet@...secur.com>,
"Ferre, Nicolas" <Nicolas.FERRE@...el.com>,
"boris.brezillon@...e-electrons.com"
<boris.brezillon@...e-electrons.com>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-watchdog@...r.kernel.org" <linux-watchdog@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>
Subject: RE: [PATCH v5 1/2] drivers: watchdog: add a driver to support
SAMA5D4 watchdog timer
Hi Guenter,
> -----Original Message-----
> From: Guenter Roeck [mailto:linux@...ck-us.net]
> Sent: 2015年8月6日 18:00
> To: Yang, Wenyou; wim@...ana.be; robh+dt@...nel.org; pawel.moll@....com;
> mark.rutland@....com; ijc+devicetree@...lion.org.uk; galak@...eaurora.org
> Cc: sylvain.rochet@...secur.com; Ferre, Nicolas; boris.brezillon@...e-
> electrons.com; devicetree@...r.kernel.org; linux-kernel@...r.kernel.org; linux-
> watchdog@...r.kernel.org; linux-arm-kernel@...ts.infradead.org
> Subject: Re: [PATCH v5 1/2] drivers: watchdog: add a driver to support SAMA5D4
> watchdog timer
>
> Hi,
>
> On 08/06/2015 01:34 AM, Wenyou Yang wrote:
> >>From SAMA5D4, the watchdog timer is upgrated with a new feature,
>
> Where does the additional ">" come from ?
I don't know why, but it isn't inclusive in my received mail.
>
> > which is describled as in the datasheet, "WDT_MR can be written until
> > a LOCKMR command is issued in WDT_CR".
> > That is to say, as long as the bootstrap and u-boot don't issue a
> > LOCKMR command, WDT_MR can be written more than once in the driver.
> >
> > So the SAMA5D4 watchdog driver's implementation is different from the
> > at91sam9260 watchdog driver implemented in file at91sam9_wdt.c.
> > The user application open the device file to enable the watchdog timer
> > hardware, and close to disable it, and set the watchdog timer timeout
> > by seting WDV and WDD fields of WDT_MR register, and ping the watchdog
> > by issuing WDRSTT command to WDT_CR register with hard-coded key.
> >
> > Signed-off-by: Wenyou Yang <wenyou.yang@...el.com>
> > ---
> > drivers/watchdog/Kconfig | 9 ++
> > drivers/watchdog/Makefile | 1 +
> > drivers/watchdog/at91sam9_wdt.h | 2 +
> > drivers/watchdog/sama5d4_wdt.c | 280
> +++++++++++++++++++++++++++++++++++++++
> > 4 files changed, 292 insertions(+)
> > create mode 100644 drivers/watchdog/sama5d4_wdt.c
> >
> > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index
> > e5e7c55..47ad39a 100644
> > --- a/drivers/watchdog/Kconfig
> > +++ b/drivers/watchdog/Kconfig
> > @@ -167,6 +167,15 @@ config AT91SAM9X_WATCHDOG
> > Watchdog timer embedded into AT91SAM9X and AT91CAP9 chips. This
> will
> > reboot your system when the timeout is reached.
> >
> > +config SAMA5D4_WATCHDOG
> > + tristate "Atmel SAMA5D4 Watchdog Timer"
> > + depends on ARCH_AT91
> > + select WATCHDOG_CORE
> > + help
> > + Atmel SAMA5D4 watchdog timer is embedded into SAMA5D4 chips.
> > + Its Watchdog Timer Mode Register can be written more than once.
> > + This will reboot your system when the timeout is reached.
> > +
> > config CADENCE_WATCHDOG
> > tristate "Cadence Watchdog Timer"
> > select WATCHDOG_CORE
> > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> > index 5c19294..f24b820 100644
> > --- a/drivers/watchdog/Makefile
> > +++ b/drivers/watchdog/Makefile
> > @@ -41,6 +41,7 @@ obj-$(CONFIG_IXP4XX_WATCHDOG) += ixp4xx_wdt.o
> > obj-$(CONFIG_KS8695_WATCHDOG) += ks8695_wdt.o
> > obj-$(CONFIG_S3C2410_WATCHDOG) += s3c2410_wdt.o
> > obj-$(CONFIG_SA1100_WATCHDOG) += sa1100_wdt.o
> > +obj-$(CONFIG_SAMA5D4_WATCHDOG) += sama5d4_wdt.o
> > obj-$(CONFIG_DW_WATCHDOG) += dw_wdt.o
> > obj-$(CONFIG_EP93XX_WATCHDOG) += ep93xx_wdt.o
> > obj-$(CONFIG_PNX4008_WATCHDOG) += pnx4008_wdt.o diff --git
> > a/drivers/watchdog/at91sam9_wdt.h b/drivers/watchdog/at91sam9_wdt.h
> > index c6fbb2e6..b79a83b 100644
> > --- a/drivers/watchdog/at91sam9_wdt.h
> > +++ b/drivers/watchdog/at91sam9_wdt.h
> > @@ -22,11 +22,13 @@
> >
> > #define AT91_WDT_MR 0x04 /* Watchdog
> Mode Register */
> > #define AT91_WDT_WDV (0xfff << 0) /*
> Counter Value */
> > +#define AT91_WDT_SET_WDV(x) ((x) &
> AT91_WDT_WDV)
> > #define AT91_WDT_WDFIEN (1 << 12) /*
> Fault Interrupt Enable */
> > #define AT91_WDT_WDRSTEN (1 << 13) /*
> Reset Processor */
> > #define AT91_WDT_WDRPROC (1 << 14) /*
> Timer Restart */
> > #define AT91_WDT_WDDIS (1 << 15) /*
> Watchdog Disable */
> > #define AT91_WDT_WDD (0xfff << 16) /*
> Delta Value */
> > +#define AT91_WDT_SET_WDD(x) (((x) << 16) &
> AT91_WDT_WDD)
> > #define AT91_WDT_WDDBGHLT (1 << 28) /*
> Debug Halt */
> > #define AT91_WDT_WDIDLEHLT (1 << 29) /*
> Idle Halt */
> >
> > diff --git a/drivers/watchdog/sama5d4_wdt.c
> > b/drivers/watchdog/sama5d4_wdt.c new file mode 100644 index
> > 0000000..a412215
> > --- /dev/null
> > +++ b/drivers/watchdog/sama5d4_wdt.c
> > @@ -0,0 +1,280 @@
> > +/*
> > + * Driver for Atmel SAMA5D4 Watchdog Timer
> > + *
> > + * Copyright (C) 2015 Atmel Corporation
> > + *
> > + * Licensed under GPLv2.
> > + */
> > +
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_irq.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/reboot.h>
> > +#include <linux/watchdog.h>
> > +
> > +#include "at91sam9_wdt.h"
> > +
> > +/* minimum and maximum watchdog timeout, in seconds */
> > +#define MIN_WDT_TIMEOUT 1
> > +#define MAX_WDT_TIMEOUT 16
> > +#define WDT_DEFAULT_TIMEOUT MAX_WDT_TIMEOUT
> > +
> > +#define WDT_SEC2TICKS(s) ((s) ? (((s) << 8) - 1) : 0)
> > +
> > +struct sama5d4_wdt {
> > + struct watchdog_device wdd;
> > + void __iomem *reg_base;
> > + u32 config;
> > +};
> > +
> > +static int wdt_timeout = WDT_DEFAULT_TIMEOUT; static bool nowayout =
> > +WATCHDOG_NOWAYOUT;
> > +
> > +module_param(wdt_timeout, int, 0);
> > +MODULE_PARM_DESC(wdt_timeout,
> > + "Watchdog timeout in seconds. (default = "
> > + __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
> > +
> > +module_param(nowayout, bool, 0);
> > +MODULE_PARM_DESC(nowayout,
> > + "Watchdog cannot be stopped once started (default="
> > + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> > +
> > +#define wdt_read(wdt, field) \
> > + readl_relaxed((wdt)->reg_base + (field))
> > +
> > +#define wdt_write(wtd, field, val) \
> > + writel_relaxed((val), (wdt)->reg_base + (field))
> > +
> > +static int sama5d4_wdt_start(struct watchdog_device *wdd) {
> > + struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
> > + u32 reg;
> > +
> > + reg = wdt_read(wdt, AT91_WDT_MR);
> > + reg &= ~AT91_WDT_WDDIS;
> > + wdt_write(wdt, AT91_WDT_MR, reg);
> > +
> > + return 0;
> > +}
> > +
> > +static int sama5d4_wdt_stop(struct watchdog_device *wdd) {
> > + struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
> > + u32 reg;
> > +
> > + reg = wdt_read(wdt, AT91_WDT_MR);
> > + reg |= AT91_WDT_WDDIS;
> > + wdt_write(wdt, AT91_WDT_MR, reg);
> > +
> > + return 0;
> > +}
> > +
> > +static int sama5d4_wdt_ping(struct watchdog_device *wdd) {
> > + struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
> > +
> > + wdt_write(wdt, AT91_WDT_CR, AT91_WDT_KEY |
> AT91_WDT_WDRSTT);
> > +
> > + return 0;
> > +}
> > +
> > +static int sama5d4_wdt_set_timeout(struct watchdog_device *wdd,
> > + unsigned int timeout)
> > +{
> > + struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
> > + u32 value = WDT_SEC2TICKS(timeout);
> > + u32 reg;
> > +
> > + reg = wdt_read(wdt, AT91_WDT_MR);
> > + reg &= ~AT91_WDT_WDV;
> > + reg &= ~AT91_WDT_WDD;
> > + reg |= AT91_WDT_SET_WDV(value);
> > + reg |= AT91_WDT_SET_WDD(value);
> > + wdt_write(wdt, AT91_WDT_MR, reg);
> > +
> > + wdd->timeout = timeout;
> > +
> > + return 0;
> > +}
> > +
> > +static const struct watchdog_info sama5d4_wdt_info = {
> > + .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
> WDIOF_KEEPALIVEPING,
> > + .identity = "Atmel SAMA5D4 Watchdog"
> > +};
> > +
> > +static struct watchdog_ops sama5d4_wdt_ops = {
> > + .owner = THIS_MODULE,
> > + .start = sama5d4_wdt_start,
> > + .stop = sama5d4_wdt_stop,
> > + .ping = sama5d4_wdt_ping,
> > + .set_timeout = sama5d4_wdt_set_timeout
>
> You made another silent change in v4: You dropped the comma here, and above
> after .identity. Now, while it makes sense to have no comma after "{ }", it does
> make sense to have the comma here, because it avoids unnecessary conflicts
> and build errors later on if a member is added at the end of the list. Please add
> those commas back in.
I will add those commas back in.
>
> Also, please stop making silent changes like this. You are making it really hard to
> review your code - now I'll have to go through it line by line again and compare it
> with your earlier patches to see if you made any other unannounced changes.
Sorry for silent changes.
I will double check it more careful before submitting the patch.
>
> Thanks,
> Guenter
Best Regards,
Wenyou Yang
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