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

From: Peter De Schrijver
Date: Fri Sep 15 2017 - 05:32:09 EST


Apart from the typo in the commit message (preemption rather than preemtion):

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
>