[ 3.5.y.z extended stable ] Patch "rtc: rtc-mv: Add support for clk to avoid lockups" has been added to staging queue
Luis Henriques
luis.henriques at canonical.com
Wed Mar 13 13:45:36 UTC 2013
On Wed, Mar 13, 2013 at 09:23:30AM -0400, Jason Cooper wrote:
> Luis,
>
> On Wed, Mar 13, 2013 at 01:07:47PM +0000, Luis Henriques wrote:
> > This is a note to let you know that I have just added a patch titled
> >
> > rtc: rtc-mv: Add support for clk to avoid lockups
> >
> > to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree
> > which can be found at:
> >
> > http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue
> >
> > If you, or anyone else, feels it should not be added to this tree, please
> > reply to this email.
> >
> > For more information about the 3.5.y.z tree, see
> > https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
> >
> > Thanks.
> > -Luis
> >
> > ------
> >
> > From 9630368a7116e76efad66622f6d22758b301e8fc Mon Sep 17 00:00:00 2001
> > From: Andrew Lunn <andrew at lunn.ch>
> > Date: Sun, 3 Feb 2013 12:32:06 +0100
> > Subject: [PATCH] rtc: rtc-mv: Add support for clk to avoid lockups
> >
> > commit 89c58c198b252f2bc20657fdd72a2aea788c435c upstream.
> >
> > The Marvell RTC on Kirkwood makes use of the runit clock. Ensure the
> > driver clk_prepare_enable() this clock, otherwise there is a danger
> > the SoC will lockup when accessing RTC registers with the clock
> > disabled.
> >
> > Reported-by: Simon Baatz <gmbnomis at gmail.com>
> > Signed-off-by: Andrew Lunn <andrew at lunn.ch>
> > Tested-by: Simon Baatz <gmbnomis at gmail.com>
> > Signed-off-by: Jason Cooper <jason at lakedaemon.net>
> > Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
> > ---
> > arch/arm/boot/dts/kirkwood.dtsi | 1 +
> > drivers/rtc/rtc-mv.c | 28 ++++++++++++++++++++++++----
> > 2 files changed, 25 insertions(+), 4 deletions(-)
>
> Please drop this patch from the v3.5.x queue. The Marvell SoCs hadn't
> converted over to common clock yet. At best this patch is a no-op, at
> worst, it breaks the kirkwood.dtsi (there is no label &gate_clk yet).
Thank you Jason, I'll drop it. I actually saw your comment regarding
this patch for the 3.4 kernel and, after taking a look at the code, it
looked like it could be included in 3.5. I was wrong :-)
Cheers,
--
Luis
>
> thx,
>
> Jason.
>
> >
> > diff --git a/arch/arm/boot/dts/kirkwood.dtsi b/arch/arm/boot/dts/kirkwood.dtsi
> > index 926528b..1c2e72c 100644
> > --- a/arch/arm/boot/dts/kirkwood.dtsi
> > +++ b/arch/arm/boot/dts/kirkwood.dtsi
> > @@ -31,6 +31,7 @@
> > compatible = "mrvl,kirkwood-rtc", "mrvl,orion-rtc";
> > reg = <0x10300 0x20>;
> > interrupts = <53>;
> > + clocks = <&gate_clk 7>;
> > };
> >
> > nand at 3000000 {
> > diff --git a/drivers/rtc/rtc-mv.c b/drivers/rtc/rtc-mv.c
> > index b2185f4..39b213e 100644
> > --- a/drivers/rtc/rtc-mv.c
> > +++ b/drivers/rtc/rtc-mv.c
> > @@ -14,6 +14,7 @@
> > #include <linux/platform_device.h>
> > #include <linux/of.h>
> > #include <linux/delay.h>
> > +#include <linux/clk.h>
> > #include <linux/gfp.h>
> > #include <linux/module.h>
> >
> > @@ -41,6 +42,7 @@ struct rtc_plat_data {
> > struct rtc_device *rtc;
> > void __iomem *ioaddr;
> > int irq;
> > + struct clk *clk;
> > };
> >
> > static int mv_rtc_set_time(struct device *dev, struct rtc_time *tm)
> > @@ -221,6 +223,7 @@ static int __devinit mv_rtc_probe(struct platform_device *pdev)
> > struct rtc_plat_data *pdata;
> > resource_size_t size;
> > u32 rtc_time;
> > + int ret = 0;
> >
> > res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > if (!res)
> > @@ -239,11 +242,17 @@ static int __devinit mv_rtc_probe(struct platform_device *pdev)
> > if (!pdata->ioaddr)
> > return -ENOMEM;
> >
> > + pdata->clk = devm_clk_get(&pdev->dev, NULL);
> > + /* Not all SoCs require a clock.*/
> > + if (!IS_ERR(pdata->clk))
> > + clk_prepare_enable(pdata->clk);
> > +
> > /* make sure the 24 hours mode is enabled */
> > rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
> > if (rtc_time & RTC_HOURS_12H_MODE) {
> > dev_err(&pdev->dev, "24 Hours mode not supported.\n");
> > - return -EINVAL;
> > + ret = -EINVAL;
> > + goto out;
> > }
> >
> > /* make sure it is actually functional */
> > @@ -252,7 +261,8 @@ static int __devinit mv_rtc_probe(struct platform_device *pdev)
> > rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
> > if (rtc_time == 0x01000000) {
> > dev_err(&pdev->dev, "internal RTC not ticking\n");
> > - return -ENODEV;
> > + ret = -ENODEV;
> > + goto out;
> > }
> > }
> >
> > @@ -268,8 +278,10 @@ static int __devinit mv_rtc_probe(struct platform_device *pdev)
> > } else
> > pdata->rtc = rtc_device_register(pdev->name, &pdev->dev,
> > &mv_rtc_ops, THIS_MODULE);
> > - if (IS_ERR(pdata->rtc))
> > - return PTR_ERR(pdata->rtc);
> > + if (IS_ERR(pdata->rtc)) {
> > + ret = PTR_ERR(pdata->rtc);
> > + goto out;
> > + }
> >
> > if (pdata->irq >= 0) {
> > writel(0, pdata->ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);
> > @@ -282,6 +294,11 @@ static int __devinit mv_rtc_probe(struct platform_device *pdev)
> > }
> >
> > return 0;
> > +out:
> > + if (!IS_ERR(pdata->clk))
> > + clk_disable_unprepare(pdata->clk);
> > +
> > + return ret;
> > }
> >
> > static int __exit mv_rtc_remove(struct platform_device *pdev)
> > @@ -292,6 +309,9 @@ static int __exit mv_rtc_remove(struct platform_device *pdev)
> > device_init_wakeup(&pdev->dev, 0);
> >
> > rtc_device_unregister(pdata->rtc);
> > + if (!IS_ERR(pdata->clk))
> > + clk_disable_unprepare(pdata->clk);
> > +
> > return 0;
> > }
> >
> > --
> > 1.8.1.2
> >
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