> -----Original Message----- > From: Alexandre Belloni [mailto:alexandre.belloni@xxxxxxxxxxxxxxxxxx] > Sent: 2017年3月3日 1:31 > To: Guenter Roeck <linux@xxxxxxxxxxxx> > Cc: Wim Van Sebroeck <wim@xxxxxxxxx>; Nicolas Ferre - M43238 > <Nicolas.Ferre@xxxxxxxxxxxxx>; Wenyou Yang - A41535 > <Wenyou.Yang@xxxxxxxxxxxxx>; linux-watchdog@xxxxxxxxxxxxxxx; linux-arm- > kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Alexandre Belloni > <alexandre.belloni@xxxxxxxxxxxxxxxxxx> > Subject: [PATCH 1/4] watchdog: sama5d4: fix WDDIS handling > > The datasheet states: "When setting the WDDIS bit, and while it is set, the fields > WDV and WDD must not be modified." > > Because the whole configuration is already cached inside .mr, wait for the user to > enable the watchdog to configure it so it is enabled and configured at the same > time (what the IP is actually expecting). > > When the watchdog is already enabled, it is not an issue to reconfigure it. Indeed, thanks. Acked-by: Wenyou.Yang <wenyou.yang@xxxxxxxxxxxxx> > > Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx> > --- > drivers/watchdog/sama5d4_wdt.c | 48 ++++++++++++++++++++++++++---------- > ------ > 1 file changed, 30 insertions(+), 18 deletions(-) > > diff --git a/drivers/watchdog/sama5d4_wdt.c b/drivers/watchdog/sama5d4_wdt.c > index f709962018ac..5cee20caca78 100644 > --- a/drivers/watchdog/sama5d4_wdt.c > +++ b/drivers/watchdog/sama5d4_wdt.c > @@ -44,6 +44,8 @@ MODULE_PARM_DESC(nowayout, > "Watchdog cannot be stopped once started (default=" > __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); > > +#define wdt_enabled (!(wdt->mr & AT91_WDT_WDDIS)) > + > #define wdt_read(wdt, field) \ > readl_relaxed((wdt)->reg_base + (field)) > > @@ -89,7 +91,16 @@ static int sama5d4_wdt_set_timeout(struct > watchdog_device *wdd, > wdt->mr &= ~AT91_WDT_WDD; > wdt->mr |= AT91_WDT_SET_WDV(value); > wdt->mr |= AT91_WDT_SET_WDD(value); > - wdt_write(wdt, AT91_WDT_MR, wdt->mr); > + > + /* > + * WDDIS has to be 0 when updating WDD/WDV. The datasheet states: > When > + * setting the WDDIS bit, and while it is set, the fields WDV and WDD > + * must not be modified. > + * If the watchdog is enabled, then the timeout can be updated. Else, > + * wait that the user enables it. > + */ > + if (wdt_enabled) > + wdt_write(wdt, AT91_WDT_MR, wdt->mr & > ~AT91_WDT_WDDIS); > > wdd->timeout = timeout; > > @@ -145,23 +156,20 @@ static int of_sama5d4_wdt_init(struct device_node *np, > struct sama5d4_wdt *wdt) > > static int sama5d4_wdt_init(struct sama5d4_wdt *wdt) { > - struct watchdog_device *wdd = &wdt->wdd; > - u32 value = WDT_SEC2TICKS(wdd->timeout); > u32 reg; > - > /* > - * Because the fields WDV and WDD must not be modified when the > WDDIS > - * bit is set, so clear the WDDIS bit before writing the WDT_MR. > + * When booting and resuming, the bootloader may have changed the > + * watchdog configuration. > + * If the watchdog is already running, we can safely update it. > + * Else, we have to disable it properly. > */ > - reg = wdt_read(wdt, AT91_WDT_MR); > - reg &= ~AT91_WDT_WDDIS; > - wdt_write(wdt, AT91_WDT_MR, reg); > - > - wdt->mr |= AT91_WDT_SET_WDD(value); > - wdt->mr |= AT91_WDT_SET_WDV(value); > - > - wdt_write(wdt, AT91_WDT_MR, wdt->mr); > - > + if (wdt_enabled) { > + wdt_write(wdt, AT91_WDT_MR, wdt->mr); > + } else { > + reg = wdt_read(wdt, AT91_WDT_MR); > + if (!(reg & AT91_WDT_WDDIS)) > + wdt_write(wdt, AT91_WDT_MR, reg | > AT91_WDT_WDDIS); > + } > return 0; > } > > @@ -172,6 +180,7 @@ static int sama5d4_wdt_probe(struct platform_device > *pdev) > struct resource *res; > void __iomem *regs; > u32 irq = 0; > + u32 timeout; > int ret; > > wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); @@ - > 221,6 +230,11 @@ static int sama5d4_wdt_probe(struct platform_device *pdev) > return ret; > } > > + timeout = WDT_SEC2TICKS(wdd->timeout); > + > + wdt->mr |= AT91_WDT_SET_WDD(timeout); > + wdt->mr |= AT91_WDT_SET_WDV(timeout); > + > ret = sama5d4_wdt_init(wdt); > if (ret) > return ret; > @@ -263,9 +277,7 @@ static int sama5d4_wdt_resume(struct device *dev) { > struct sama5d4_wdt *wdt = dev_get_drvdata(dev); > > - wdt_write(wdt, AT91_WDT_MR, wdt->mr & ~AT91_WDT_WDDIS); > - if (wdt->mr & AT91_WDT_WDDIS) > - wdt_write(wdt, AT91_WDT_MR, wdt->mr); > + sama5d4_wdt_init(wdt); > > return 0; > } > -- > 2.11.0 Best Regards, Wenyou Yang ?韬{.n?????%??檩??w?{.n???{??h?Ф?塄}?财??j:+v?? ? ???2??璀??摺?囤??z夸z罐?+?????w棹f
