Re: [PATCH] clk: tegra: Use readl_relaxed_poll_timeout_atomic in tegra210_clock_init

From: Nicolin Chen
Date: Sat Sep 16 2017 - 01:27:16 EST


On Fri, Sep 15, 2017 at 12:31:45PM +0300, Peter De Schrijver wrote:
> Apart from the typo in the commit message (preemption rather than preemtion):

Sent a v2 to correct it. And included your Acked-by.

Thanks

>
> Acked-By: Peter De Schrijver <pdeschrijver@xxxxxxxxxx>
>
> On Thu, Sep 14, 2017 at 06:36:14PM -0700, Nicolin Chen wrote:
> > Below is the call trace of tegra210_init_pllu() function:
> > start_kernel()
> > -> time_init()
> > --> of_clk_init()
> > ---> tegra210_clock_init()
> > ----> tegra210_pll_init()
> > -----> tegra210_init_pllu()
> >
> > Because the preemtion is disabled in the start_kernel before calling
> > time_init, tegra210_init_pllu is actually in an atomic context while
> > it includes a readl_relaxed_poll_timeout that might sleep.
> >
> > So this patch just changes this readl_relaxed_poll_timeout() to its
> > atomic version.
> >
> > Signed-off-by: Nicolin Chen <nicoleotsuka@xxxxxxxxx>
> > ---
> > drivers/clk/tegra/clk-tegra210.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/clk/tegra/clk-tegra210.c b/drivers/clk/tegra/clk-tegra210.c
> > index 0b9789a..ea695c4 100644
> > --- a/drivers/clk/tegra/clk-tegra210.c
> > +++ b/drivers/clk/tegra/clk-tegra210.c
> > @@ -2587,8 +2587,8 @@ static int tegra210_enable_pllu(void)
> > reg |= PLL_ENABLE;
> > writel(reg, clk_base + PLLU_BASE);
> >
> > - readl_relaxed_poll_timeout(clk_base + PLLU_BASE, reg,
> > - reg & PLL_BASE_LOCK, 2, 1000);
> > + readl_relaxed_poll_timeout_atomic(clk_base + PLLU_BASE, reg,
> > + reg & PLL_BASE_LOCK, 2, 1000);
> > if (!(reg & PLL_BASE_LOCK)) {
> > pr_err("Timed out waiting for PLL_U to lock\n");
> > return -ETIMEDOUT;
> > --
> > 2.1.4
> >