clk: tegra: Use readl_relaxed_poll_timeout_atomic in tegra210_clock_init

Message ID 1505439374-8666-1-git-send-email-nicoleotsuka@gmail.com
State Superseded
Headers show
Series
  • clk: tegra: Use readl_relaxed_poll_timeout_atomic in tegra210_clock_init
Related show

Commit Message

Nicolin Chen Sept. 15, 2017, 1:36 a.m.
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@gmail.com>
---
 drivers/clk/tegra/clk-tegra210.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Peter De Schrijver Sept. 15, 2017, 9:31 a.m. | #1
Apart from the typo in the commit message (preemption rather than preemtion):

Acked-By: Peter De Schrijver <pdeschrijver@nvidia.com>

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@gmail.com>
> ---
>  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
> 
--
To unsubscribe from this list: send the line "unsubscribe linux-tegra" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Nicolin Chen Sept. 16, 2017, 5:26 a.m. | #2
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@nvidia.com>
> 
> 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@gmail.com>
> > ---
> >  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
> > 
--
To unsubscribe from this list: send the line "unsubscribe linux-tegra" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

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;