[PATCH v2] ARM: davinci: da8xx: Fix sleeping function called from invalid context

[PATCH v2] ARM: davinci: da8xx: Fix sleeping function called from invalid context

[Alexandre Bailon]

Everytime the usb20 phy is enabled, there is a
"sleeping function called from invalid context" BUG.

clk_enable() from arch/arm/mach-davinci/clock.c uses spin_lock_irqsave()
before to invoke the callback usb20_phy_clk_enable().
usb20_phy_clk_enable() uses clk_get() and clk_enable_prepapre()
which may sleep.
Move clk_get() to da8xx_register_usb20_phy_clk() and
replace clk_prepare_enable() by clk_enable().

Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
---
 arch/arm/mach-davinci/usb-da8xx.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/arch/arm/mach-davinci/usb-da8xx.c b/arch/arm/mach-davinci/usb-da8xx.c
index b010e5f..2baa0e1 100644
--- a/arch/arm/mach-davinci/usb-da8xx.c
+++ b/arch/arm/mach-davinci/usb-da8xx.c
@@ -156,23 +156,18 @@ int __init da8xx_register_usb_refclkin(int rate)
 	return 0;
 }
 
+static struct clk *usb20_clk;
+
 static void usb20_phy_clk_enable(struct clk *clk)
 {
-	struct clk *usb20_clk;
 	int err;
 	u32 val;
 	u32 timeout = 500000; /* 500 msec */
 
 	val = readl(DA8XX_SYSCFG0_VIRT(DA8XX_CFGCHIP2_REG));
 
-	usb20_clk = clk_get(&da8xx_usb20_dev.dev, "usb20");
-	if (IS_ERR(usb20_clk)) {
-		pr_err("could not get usb20 clk: %ld\n", PTR_ERR(usb20_clk));
-		return;
-	}
-
 	/* The USB 2.O PLL requires that the USB 2.O PSC is enabled as well. */
-	err = clk_prepare_enable(usb20_clk);
+	err = clk_enable(usb20_clk);
 	if (err) {
 		pr_err("failed to enable usb20 clk: %d\n", err);
 		clk_put(usb20_clk);
@@ -197,8 +192,7 @@ static void usb20_phy_clk_enable(struct clk *clk)
 
 	pr_err("Timeout waiting for USB 2.0 PHY clock good\n");
 done:
-	clk_disable_unprepare(usb20_clk);
-	clk_put(usb20_clk);
+	clk_disable(usb20_clk);
 }
 
 static void usb20_phy_clk_disable(struct clk *clk)
@@ -287,9 +281,15 @@ int __init da8xx_register_usb20_phy_clk(bool use_usb_refclkin)
 	struct clk *parent;
 	int ret = 0;
 
+	usb20_clk = clk_get(&da8xx_usb20_dev.dev, "usb20");
+	if (IS_ERR(usb20_clk))
+		return PTR_ERR(parent);
+
 	parent = clk_get(NULL, use_usb_refclkin ? "usb_refclkin" : "pll0_aux");
-	if (IS_ERR(parent))
+	if (IS_ERR(parent)) {
+		clk_put(usb20_clk);
 		return PTR_ERR(parent);
+	}
 
 	usb20_phy_clk.parent = parent;
 	ret = clk_register(&usb20_phy_clk);
-- 
2.7.3

[PATCH v2] ARM: davinci: da8xx: Fix sleeping function called from invalid context

[Sekhar Nori]

On Tuesday 29 November 2016 10:18 PM, Alexandre Bailon wrote:
> Everytime the usb20 phy is enabled, there is a
> "sleeping function called from invalid context" BUG.
> 
> clk_enable() from arch/arm/mach-davinci/clock.c uses spin_lock_irqsave()
> before to invoke the callback usb20_phy_clk_enable().

"before invocation of the callback"? (doesn't read right otherwise)

> usb20_phy_clk_enable() uses clk_get() and clk_enable_prepapre()

clk_prepare_enable()

> which may sleep.
> Move clk_get() to da8xx_register_usb20_phy_clk() and
> replace clk_prepare_enable() by clk_enable().
> 
> Signed-off-by: Alexandre Bailon <abailon@baylibre.com>

> @@ -287,9 +281,15 @@ int __init da8xx_register_usb20_phy_clk(bool use_usb_refclkin)
>  	struct clk *parent;
>  	int ret = 0;
>  
> +	usb20_clk = clk_get(&da8xx_usb20_dev.dev, "usb20");
> +	if (IS_ERR(usb20_clk))
> +		return PTR_ERR(parent);

Typo here. Should be PTR_ERR(usb20_clk)

Thanks,
Sekhar

[PATCH v2] ARM: davinci: da8xx: Fix sleeping function called from invalid context

[Arnd Bergmann]

On Thursday, December 1, 2016 7:47:12 PM CET Sekhar Nori wrote:
> 
> > @@ -287,9 +281,15 @@ int __init da8xx_register_usb20_phy_clk(bool use_usb_refclkin)
> >       struct clk *parent;
> >       int ret = 0;
> >  
> > +     usb20_clk = clk_get(&da8xx_usb20_dev.dev, "usb20");
> > +     if (IS_ERR(usb20_clk))
> > +             return PTR_ERR(parent);
> 
> Typo here. Should be PTR_ERR(usb20_clk)

I found that doing

		err = PTR_ERR_OR_ZERO(usb20_clk);
		if (err)
			return err;

is less error-prone and leads to better object code.

	Arnd

[PATCH v2] ARM: davinci: da8xx: Fix sleeping function called from invalid context

[Alexandre Bailon]

On 12/01/2016 03:59 PM, Arnd Bergmann wrote:
> On Thursday, December 1, 2016 7:47:12 PM CET Sekhar Nori wrote:
>>
>>> @@ -287,9 +281,15 @@ int __init da8xx_register_usb20_phy_clk(bool use_usb_refclkin)
>>>       struct clk *parent;
>>>       int ret = 0;
>>>  
>>> +     usb20_clk = clk_get(&da8xx_usb20_dev.dev, "usb20");
>>> +     if (IS_ERR(usb20_clk))
>>> +             return PTR_ERR(parent);
>>
>> Typo here. Should be PTR_ERR(usb20_clk)
> 
> I found that doing
> 
> 		err = PTR_ERR_OR_ZERO(usb20_clk);
> 		if (err)
> 			return err;
> 
> is less error-prone and leads to better object code.
> 
> 	Arnd
> 
I didn't know that one.
I will use it.

Thanks,
Alexandre