[PATCH V2] clk: qcom: clk-alpha-pll: Simplify the zonda_pll_adjust_l_val()

[PATCH V2] clk: qcom: clk-alpha-pll: Simplify the zonda_pll_adjust_l_val()

[Satya Priya Kakitapalli]

In zonda_pll_adjust_l_val() replace the divide operator with comparison
operator since comparisons are faster than divisions. Also, simplify the
logic and remove the unnecessary 'quotient' local variable.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202408110724.8pqbpDiD-lkp@intel.com/
Signed-off-by: Satya Priya Kakitapalli <quic_skakitap@quicinc.com>
Reviewed-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
---
Changes in V2:
 - Simplify the logic and remove unnecessary quotient variable.
 - Remove Fixes tag as this is just a simplification.

 drivers/clk/qcom/clk-alpha-pll.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/clk/qcom/clk-alpha-pll.c b/drivers/clk/qcom/clk-alpha-pll.c
index 2f620ccb41cb..4ce3347beb39 100644
--- a/drivers/clk/qcom/clk-alpha-pll.c
+++ b/drivers/clk/qcom/clk-alpha-pll.c
@@ -2120,14 +2120,11 @@ static void clk_zonda_pll_disable(struct clk_hw *hw)
 
 static void zonda_pll_adjust_l_val(unsigned long rate, unsigned long prate, u32 *l)
 {
-	u64 remainder, quotient;
+	u64 remainder;
 
-	quotient = rate;
-	remainder = do_div(quotient, prate);
-	*l = quotient;
+	remainder = do_div(rate, prate);
 
-	if ((remainder * 2) / prate)
-		*l = *l + 1;
+	*l = rate + (u32)(remainder * 2 >= prate);
 }
 
 static int clk_zonda_pll_set_rate(struct clk_hw *hw, unsigned long rate,
-- 
2.25.1

Re: [PATCH V2] clk: qcom: clk-alpha-pll: Simplify the zonda_pll_adjust_l_val()

[Bjorn Andersson]

On Wed, Aug 14, 2024 at 03:50:05PM GMT, Satya Priya Kakitapalli wrote:
> In zonda_pll_adjust_l_val() replace the divide operator with comparison
> operator since comparisons are faster than divisions. Also, simplify the
> logic and remove the unnecessary 'quotient' local variable.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Closes: https://lore.kernel.org/r/202408110724.8pqbpDiD-lkp@intel.com/
> Signed-off-by: Satya Priya Kakitapalli <quic_skakitap@quicinc.com>
> Reviewed-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
> ---
> Changes in V2:
>  - Simplify the logic and remove unnecessary quotient variable.
>  - Remove Fixes tag as this is just a simplification.
> 
>  drivers/clk/qcom/clk-alpha-pll.c | 9 +++------
>  1 file changed, 3 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/clk/qcom/clk-alpha-pll.c b/drivers/clk/qcom/clk-alpha-pll.c
> index 2f620ccb41cb..4ce3347beb39 100644
> --- a/drivers/clk/qcom/clk-alpha-pll.c
> +++ b/drivers/clk/qcom/clk-alpha-pll.c
> @@ -2120,14 +2120,11 @@ static void clk_zonda_pll_disable(struct clk_hw *hw)
>  
>  static void zonda_pll_adjust_l_val(unsigned long rate, unsigned long prate, u32 *l)
>  {
> -	u64 remainder, quotient;
> +	u64 remainder;
>  
> -	quotient = rate;
> -	remainder = do_div(quotient, prate);
> -	*l = quotient;
> +	remainder = do_div(rate, prate);

This does not compile on arm32 target.

Regards,
Bjorn

>  
> -	if ((remainder * 2) / prate)
> -		*l = *l + 1;
> +	*l = rate + (u32)(remainder * 2 >= prate);
>  }
>  
>  static int clk_zonda_pll_set_rate(struct clk_hw *hw, unsigned long rate,
> -- 
> 2.25.1
> 

Re: [PATCH V2] clk: qcom: clk-alpha-pll: Simplify the zonda_pll_adjust_l_val()

[Satya Priya Kakitapalli]

On 8/16/2024 3:00 AM, Bjorn Andersson wrote:
> On Wed, Aug 14, 2024 at 03:50:05PM GMT, Satya Priya Kakitapalli wrote:
>> In zonda_pll_adjust_l_val() replace the divide operator with comparison
>> operator since comparisons are faster than divisions. Also, simplify the
>> logic and remove the unnecessary 'quotient' local variable.
>>
>> Reported-by: kernel test robot <lkp@intel.com>
>> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
>> Closes: https://lore.kernel.org/r/202408110724.8pqbpDiD-lkp@intel.com/
>> Signed-off-by: Satya Priya Kakitapalli <quic_skakitap@quicinc.com>
>> Reviewed-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
>> ---
>> Changes in V2:
>>   - Simplify the logic and remove unnecessary quotient variable.
>>   - Remove Fixes tag as this is just a simplification.
>>
>>   drivers/clk/qcom/clk-alpha-pll.c | 9 +++------
>>   1 file changed, 3 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/clk/qcom/clk-alpha-pll.c b/drivers/clk/qcom/clk-alpha-pll.c
>> index 2f620ccb41cb..4ce3347beb39 100644
>> --- a/drivers/clk/qcom/clk-alpha-pll.c
>> +++ b/drivers/clk/qcom/clk-alpha-pll.c
>> @@ -2120,14 +2120,11 @@ static void clk_zonda_pll_disable(struct clk_hw *hw)
>>   
>>   static void zonda_pll_adjust_l_val(unsigned long rate, unsigned long prate, u32 *l)
>>   {
>> -	u64 remainder, quotient;
>> +	u64 remainder;
>>   
>> -	quotient = rate;
>> -	remainder = do_div(quotient, prate);
>> -	*l = quotient;
>> +	remainder = do_div(rate, prate);
> This does not compile on arm32 target.


Could you please confirm if it is because of the do_div? I see the 
do_div() API is used at multiple places in the same driver already.


> Regards,
> Bjorn
>
>>   
>> -	if ((remainder * 2) / prate)
>> -		*l = *l + 1;
>> +	*l = rate + (u32)(remainder * 2 >= prate);
>>   }
>>   
>>   static int clk_zonda_pll_set_rate(struct clk_hw *hw, unsigned long rate,
>> -- 
>> 2.25.1
>>

Re: [PATCH V2] clk: qcom: clk-alpha-pll: Simplify the zonda_pll_adjust_l_val()

[kernel test robot]

Hi Satya,

kernel test robot noticed the following build errors:

[auto build test ERROR on next-20240814]
[cannot apply to clk/clk-next v6.11-rc3 v6.11-rc2 v6.11-rc1 linus/master v6.11-rc3]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Satya-Priya-Kakitapalli/clk-qcom-clk-alpha-pll-Simplify-the-zonda_pll_adjust_l_val/20240815-001519
base:   next-20240814
patch link:    https://lore.kernel.org/r/20240814102005.33493-1-quic_skakitap%40quicinc.com
patch subject: [PATCH V2] clk: qcom: clk-alpha-pll: Simplify the zonda_pll_adjust_l_val()
config: hexagon-allmodconfig (https://download.01.org/0day-ci/archive/20240817/202408171932.T7RdTd9M-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 26670e7fa4f032a019d23d56c6a02926e854e8af)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240817/202408171932.T7RdTd9M-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202408171932.T7RdTd9M-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from drivers/clk/qcom/clk-alpha-pll.c:10:
   In file included from include/linux/regmap.h:20:
   In file included from include/linux/iopoll.h:14:
   In file included from include/linux/io.h:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:548:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     548 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:561:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     561 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from drivers/clk/qcom/clk-alpha-pll.c:10:
   In file included from include/linux/regmap.h:20:
   In file included from include/linux/iopoll.h:14:
   In file included from include/linux/io.h:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:574:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     574 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from drivers/clk/qcom/clk-alpha-pll.c:10:
   In file included from include/linux/regmap.h:20:
   In file included from include/linux/iopoll.h:14:
   In file included from include/linux/io.h:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:585:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     585 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:595:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     595 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:605:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     605 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   drivers/clk/qcom/clk-alpha-pll.c:2125:14: warning: comparison of distinct pointer types ('typeof ((rate)) *' (aka 'unsigned long *') and 'uint64_t *' (aka 'unsigned long long *')) [-Wcompare-distinct-pointer-types]
    2125 |         remainder = do_div(rate, prate);
         |                     ^~~~~~~~~~~~~~~~~~~
   include/asm-generic/div64.h:222:28: note: expanded from macro 'do_div'
     222 |         (void)(((typeof((n)) *)0) == ((uint64_t *)0));  \
         |                ~~~~~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~~
>> drivers/clk/qcom/clk-alpha-pll.c:2125:14: error: incompatible pointer types passing 'unsigned long *' to parameter of type 'uint64_t *' (aka 'unsigned long long *') [-Werror,-Wincompatible-pointer-types]
    2125 |         remainder = do_div(rate, prate);
         |                     ^~~~~~~~~~~~~~~~~~~
   include/asm-generic/div64.h:238:22: note: expanded from macro 'do_div'
     238 |                 __rem = __div64_32(&(n), __base);       \
         |                                    ^~~~
   include/asm-generic/div64.h:213:38: note: passing argument to parameter 'dividend' here
     213 | extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor);
         |                                      ^
   drivers/clk/qcom/clk-alpha-pll.c:2125:14: warning: shift count >= width of type [-Wshift-count-overflow]
    2125 |         remainder = do_div(rate, prate);
         |                     ^~~~~~~~~~~~~~~~~~~
   include/asm-generic/div64.h:234:25: note: expanded from macro 'do_div'
     234 |         } else if (likely(((n) >> 32) == 0)) {          \
         |                                ^  ~~
   include/linux/compiler.h:76:40: note: expanded from macro 'likely'
      76 | # define likely(x)      __builtin_expect(!!(x), 1)
         |                                             ^
   8 warnings and 1 error generated.


vim +2125 drivers/clk/qcom/clk-alpha-pll.c

  2120	
  2121	static void zonda_pll_adjust_l_val(unsigned long rate, unsigned long prate, u32 *l)
  2122	{
  2123		u64 remainder;
  2124	
> 2125		remainder = do_div(rate, prate);
  2126	
  2127		*l = rate + (u32)(remainder * 2 >= prate);
  2128	}
  2129	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH V2] clk: qcom: clk-alpha-pll: Simplify the zonda_pll_adjust_l_val()

[kernel test robot]

Hi Satya,

kernel test robot noticed the following build warnings:

[auto build test WARNING on next-20240814]
[cannot apply to clk/clk-next v6.11-rc3 v6.11-rc2 v6.11-rc1 linus/master v6.11-rc3]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Satya-Priya-Kakitapalli/clk-qcom-clk-alpha-pll-Simplify-the-zonda_pll_adjust_l_val/20240815-001519
base:   next-20240814
patch link:    https://lore.kernel.org/r/20240814102005.33493-1-quic_skakitap%40quicinc.com
patch subject: [PATCH V2] clk: qcom: clk-alpha-pll: Simplify the zonda_pll_adjust_l_val()
config: hexagon-allyesconfig (https://download.01.org/0day-ci/archive/20240817/202408172049.Mc8dSq0c-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 26670e7fa4f032a019d23d56c6a02926e854e8af)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240817/202408172049.Mc8dSq0c-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202408172049.Mc8dSq0c-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from drivers/clk/qcom/clk-alpha-pll.c:10:
   In file included from include/linux/regmap.h:20:
   In file included from include/linux/iopoll.h:14:
   In file included from include/linux/io.h:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:548:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     548 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:561:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     561 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from drivers/clk/qcom/clk-alpha-pll.c:10:
   In file included from include/linux/regmap.h:20:
   In file included from include/linux/iopoll.h:14:
   In file included from include/linux/io.h:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:574:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     574 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from drivers/clk/qcom/clk-alpha-pll.c:10:
   In file included from include/linux/regmap.h:20:
   In file included from include/linux/iopoll.h:14:
   In file included from include/linux/io.h:14:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:585:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     585 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:595:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     595 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:605:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     605 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
>> drivers/clk/qcom/clk-alpha-pll.c:2125:14: warning: comparison of distinct pointer types ('typeof ((rate)) *' (aka 'unsigned long *') and 'uint64_t *' (aka 'unsigned long long *')) [-Wcompare-distinct-pointer-types]
    2125 |         remainder = do_div(rate, prate);
         |                     ^~~~~~~~~~~~~~~~~~~
   include/asm-generic/div64.h:222:28: note: expanded from macro 'do_div'
     222 |         (void)(((typeof((n)) *)0) == ((uint64_t *)0));  \
         |                ~~~~~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~~
   drivers/clk/qcom/clk-alpha-pll.c:2125:14: error: incompatible pointer types passing 'unsigned long *' to parameter of type 'uint64_t *' (aka 'unsigned long long *') [-Werror,-Wincompatible-pointer-types]
    2125 |         remainder = do_div(rate, prate);
         |                     ^~~~~~~~~~~~~~~~~~~
   include/asm-generic/div64.h:238:22: note: expanded from macro 'do_div'
     238 |                 __rem = __div64_32(&(n), __base);       \
         |                                    ^~~~
   include/asm-generic/div64.h:213:38: note: passing argument to parameter 'dividend' here
     213 | extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor);
         |                                      ^
>> drivers/clk/qcom/clk-alpha-pll.c:2125:14: warning: shift count >= width of type [-Wshift-count-overflow]
    2125 |         remainder = do_div(rate, prate);
         |                     ^~~~~~~~~~~~~~~~~~~
   include/asm-generic/div64.h:234:25: note: expanded from macro 'do_div'
     234 |         } else if (likely(((n) >> 32) == 0)) {          \
         |                                ^  ~~
   include/linux/compiler.h:76:40: note: expanded from macro 'likely'
      76 | # define likely(x)      __builtin_expect(!!(x), 1)
         |                                             ^
   8 warnings and 1 error generated.


vim +2125 drivers/clk/qcom/clk-alpha-pll.c

  2120	
  2121	static void zonda_pll_adjust_l_val(unsigned long rate, unsigned long prate, u32 *l)
  2122	{
  2123		u64 remainder;
  2124	
> 2125		remainder = do_div(rate, prate);
  2126	
  2127		*l = rate + (u32)(remainder * 2 >= prate);
  2128	}
  2129	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki