From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicolin Chen Subject: Re: [PATCH] clk: tegra: Use readl_relaxed_poll_timeout_atomic in tegra210_clock_init Date: Fri, 15 Sep 2017 22:26:28 -0700 Message-ID: <20170916052626.GA3704@Asurada> References: <1505439374-8666-1-git-send-email-nicoleotsuka@gmail.com> <20170915093145.GD6290@tbergstrom-lnx.Nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20170915093145.GD6290-Rysk9IDjsxmJz7etNGeUX8VPkgjIgRvpAL8bYrjMMd8@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Peter De Schrijver Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-clk-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, sboyd-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, mturquette-rdvid1DuHRBWk0Htik3J/w@public.gmane.org, pgaikwad-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org List-Id: linux-tegra@vger.kernel.org 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 > > 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 > > --- > > 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 > >