[patch] clk: vt8500: several forever loops

[patch] clk: vt8500: several forever loops

[Dan Carpenter]

This does a bunch of looping like this:

	for (div2 = 7; div2 >= 0; div2--)

But unsigned values are always greater than or equal to zero so it just
loops and loops.  Really "mul", "div1" and "div2" should all be declared
as int for cleanliness sake.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
Static checker stuff.

diff --git a/drivers/clk/clk-vt8500.c b/drivers/clk/clk-vt8500.c
index 82306f5..8d5b57c 100644
--- a/drivers/clk/clk-vt8500.c
+++ b/drivers/clk/clk-vt8500.c
@@ -363,7 +363,7 @@ static void vt8500_find_pll_bits(unsigned long rate, unsigned long parent_rate,
 static void wm8650_find_pll_bits(unsigned long rate, unsigned long parent_rate,
 				u32 *multiplier, u32 *divisor1, u32 *divisor2)
 {
-	u32 mul, div1, div2;
+	int mul, div1, div2;
 	u32 best_mul, best_div1, best_div2;
 	unsigned long tclk, rate_err, best_err;
 
@@ -431,7 +431,7 @@ static u32 wm8750_get_filter(u32 parent_rate, u32 divisor1)
 static void wm8750_find_pll_bits(unsigned long rate, unsigned long parent_rate,
 				u32 *filter, u32 *multiplier, u32 *divisor1, u32 *divisor2)
 {
-	u32 mul, div1, div2;
+	int mul, div1, div2;
 	u32 best_mul, best_div1, best_div2;
 	unsigned long tclk, rate_err, best_err;
 
@@ -475,7 +475,7 @@ static void wm8750_find_pll_bits(unsigned long rate, unsigned long parent_rate,
 static void wm8850_find_pll_bits(unsigned long rate, unsigned long parent_rate,
 				u32 *multiplier, u32 *divisor1, u32 *divisor2)
 {
-	u32 mul, div1, div2;
+	int mul, div1, div2;
 	u32 best_mul, best_div1, best_div2;
 	unsigned long tclk, rate_err, best_err;
 

[patch] clk: vt8500: several forever loops

[Dan Carpenter]

This patch is still needed in linux-next.  It was Acked by Tony Prisk in
a private email.

Acked-by: Tony Prisk <linux@prisktech.co.nz>

regards,
dan carpenter

On Mon, Aug 26, 2013 at 07:02:33PM +0300, Dan Carpenter wrote:
> This does a bunch of looping like this:
> 
> 	for (div2 = 7; div2 >= 0; div2--)
> 
> But unsigned values are always greater than or equal to zero so it just
> loops and loops.  Really "mul", "div1" and "div2" should all be declared
> as int for cleanliness sake.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> Static checker stuff.
> 
> diff --git a/drivers/clk/clk-vt8500.c b/drivers/clk/clk-vt8500.c
> index 82306f5..8d5b57c 100644
> --- a/drivers/clk/clk-vt8500.c
> +++ b/drivers/clk/clk-vt8500.c
> @@ -363,7 +363,7 @@ static void vt8500_find_pll_bits(unsigned long rate, unsigned long parent_rate,
>  static void wm8650_find_pll_bits(unsigned long rate, unsigned long parent_rate,
>  				u32 *multiplier, u32 *divisor1, u32 *divisor2)
>  {
> -	u32 mul, div1, div2;
> +	int mul, div1, div2;
>  	u32 best_mul, best_div1, best_div2;
>  	unsigned long tclk, rate_err, best_err;
>  
> @@ -431,7 +431,7 @@ static u32 wm8750_get_filter(u32 parent_rate, u32 divisor1)
>  static void wm8750_find_pll_bits(unsigned long rate, unsigned long parent_rate,
>  				u32 *filter, u32 *multiplier, u32 *divisor1, u32 *divisor2)
>  {
> -	u32 mul, div1, div2;
> +	int mul, div1, div2;
>  	u32 best_mul, best_div1, best_div2;
>  	unsigned long tclk, rate_err, best_err;
>  
> @@ -475,7 +475,7 @@ static void wm8750_find_pll_bits(unsigned long rate, unsigned long parent_rate,
>  static void wm8850_find_pll_bits(unsigned long rate, unsigned long parent_rate,
>  				u32 *multiplier, u32 *divisor1, u32 *divisor2)
>  {
> -	u32 mul, div1, div2;
> +	int mul, div1, div2;
>  	u32 best_mul, best_div1, best_div2;
>  	unsigned long tclk, rate_err, best_err;
>  

[patch] clk: vt8500: several forever loops

[Ard Biesheuvel]

On 2 April 2014 13:04, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> This patch is still needed in linux-next.  It was Acked by Tony Prisk in
> a private email.
>
> Acked-by: Tony Prisk <linux@prisktech.co.nz>
>
> regards,
> dan carpenter
>
> On Mon, Aug 26, 2013 at 07:02:33PM +0300, Dan Carpenter wrote:
>> This does a bunch of looping like this:
>>
>>       for (div2 = 7; div2 >= 0; div2--)
>>
>> But unsigned values are always greater than or equal to zero so it just
>> loops and loops.  Really "mul", "div1" and "div2" should all be declared
>> as int for cleanliness sake.
>>

Apologies if this is a silly question from someone who is utterly
uninformed, but are values == 0 even legal for divisors?
It seems that, at least in some cases, 'div - 1' is or'ed into a
register value (WM8850_BITS_TO_VAL), and I don't think you are
expecting negative values there.
So perhaps instead, change the test to '> 0' ??

Regards,
Ard.





>> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>> ---
>> Static checker stuff.
>>
>> diff --git a/drivers/clk/clk-vt8500.c b/drivers/clk/clk-vt8500.c
>> index 82306f5..8d5b57c 100644
>> --- a/drivers/clk/clk-vt8500.c
>> +++ b/drivers/clk/clk-vt8500.c
>> @@ -363,7 +363,7 @@ static void vt8500_find_pll_bits(unsigned long rate, unsigned long parent_rate,
>>  static void wm8650_find_pll_bits(unsigned long rate, unsigned long parent_rate,
>>                               u32 *multiplier, u32 *divisor1, u32 *divisor2)
>>  {
>> -     u32 mul, div1, div2;
>> +     int mul, div1, div2;
>>       u32 best_mul, best_div1, best_div2;
>>       unsigned long tclk, rate_err, best_err;
>>
>> @@ -431,7 +431,7 @@ static u32 wm8750_get_filter(u32 parent_rate, u32 divisor1)
>>  static void wm8750_find_pll_bits(unsigned long rate, unsigned long parent_rate,
>>                               u32 *filter, u32 *multiplier, u32 *divisor1, u32 *divisor2)
>>  {
>> -     u32 mul, div1, div2;
>> +     int mul, div1, div2;
>>       u32 best_mul, best_div1, best_div2;
>>       unsigned long tclk, rate_err, best_err;
>>
>> @@ -475,7 +475,7 @@ static void wm8750_find_pll_bits(unsigned long rate, unsigned long parent_rate,
>>  static void wm8850_find_pll_bits(unsigned long rate, unsigned long parent_rate,
>>                               u32 *multiplier, u32 *divisor1, u32 *divisor2)
>>  {
>> -     u32 mul, div1, div2;
>> +     int mul, div1, div2;
>>       u32 best_mul, best_div1, best_div2;
>>       unsigned long tclk, rate_err, best_err;
>>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[patch] clk: vt8500: several forever loops

[Dan Carpenter]

On Wed, Apr 02, 2014 at 01:19:19PM +0200, Ard Biesheuvel wrote:
> On 2 April 2014 13:04, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> > This patch is still needed in linux-next.  It was Acked by Tony Prisk in
> > a private email.
> >
> > Acked-by: Tony Prisk <linux@prisktech.co.nz>
> >
> > regards,
> > dan carpenter
> >
> > On Mon, Aug 26, 2013 at 07:02:33PM +0300, Dan Carpenter wrote:
> >> This does a bunch of looping like this:
> >>
> >>       for (div2 = 7; div2 >= 0; div2--)
> >>
> >> But unsigned values are always greater than or equal to zero so it just
> >> loops and loops.  Really "mul", "div1" and "div2" should all be declared
> >> as int for cleanliness sake.
> >>
> 
> Apologies if this is a silly question from someone who is utterly
> uninformed, but are values == 0 even legal for divisors?
> It seems that, at least in some cases, 'div - 1' is or'ed into a
> register value (WM8850_BITS_TO_VAL), and I don't think you are
> expecting negative values there.
> So perhaps instead, change the test to '> 0' ??

Those seem like totally valid points.  The truth is that I almost am
"utterly uninformed" about this code.  Perhaps someone who knows more
than the both of us could take a look?

Please give Ard and me reported by tags when you fix this.

regards,
dan carpenter