[U-Boot] Question about compile warnings of exynos clock

From: Jaehoon Chung <jh80.chung@samsung.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] Question about compile warnings of exynos clock
Date: Tue, 13 Jan 2015 13:10:44 +0900	[thread overview]
Message-ID: <54B49AC4.3090106@samsung.com> (raw)
In-Reply-To: <CAPnjgZ2z9B=DAz2gPAVO58KNt0no_aOpTTtuTfr+R2uFywWuiA@mail.gmail.com>

Hi,

On 01/13/2015 11:56 AM, Simon Glass wrote:
> Hi,
> 
> On 12 January 2015 at 18:51, Joonyoung Shim <jy0922.shim@samsung.com> wrote:
>> Hi,
>>
>> On 01/13/2015 11:47 AM, Simon Glass wrote:
>>> Hi,
>>>
>>> On 12 January 2015 at 18:36, Joonyoung Shim <jy0922.shim@samsung.com> wrote:
>>>> Hi,
>>>>
>>>> On 01/13/2015 11:27 AM, Simon Glass wrote:
>>>>> Hi,
>>>>>
>>>>> On 12 January 2015 at 18:24, Joonyoung Shim <jy0922.shim@samsung.com> wrote:
>>>>>> Hi,
>>>>>>
>>>>>> I found below compile warnings,
>>>>>>
>>>>>>   CC      arch/arm/cpu/armv7/exynos/clock.o
>>>>>> arch/arm/cpu/armv7/exynos/clock.c: In function ?clock_get_periph_rate?:
>>>>>> arch/arm/cpu/armv7/exynos/clock.c:265:47: warning: array subscript is above array bounds [-Warray-bounds]
>>>>>>   struct clk_bit_info *bit_info = &clk_bit_info[peripheral];
>>>>>>                                                ^
>>>>>> arch/arm/cpu/armv7/exynos/clock.c:265:47: warning: array subscript is above array bounds [-Warray-bounds]
>>>>>>
>>>>>> ...
>>>>>>> static unsigned long exynos5_get_periph_rate(int peripheral)
>>>>>>> {
>>>>>>>         struct clk_bit_info *bit_info = &clk_bit_info[peripheral];
>>>>>>>
>>>>>>
>>>>>> This can access out of bounds of clk_bit_info[] array from
>>>>>> exynos5_get_periph_rate(). The peripheral value comes from
>>>>>> enum periph_id but it gets out of count clk_bit_info[] array.
>>>>>>
>>>>>> So, i don't think exynos5_get_periph_rate is working correctly.
>>>>>> Currently, exynos5_get_periph_rate is used by clock_get_periph_rate only
>>>>>> from get_pwm_clk.
>>>>>>
>>>>>> Is it ongoing to work for generic api to get the clk freq? If not,
>>>>>> let's remove exynos5_get_periph_rate and clock_get_periph_rate.
>>>>>
>>>>> That's going in the wrong direction - these functions make the code
>>>>> much easier to follow and refactor. We should remove get_pwm_clk(),
>>>>> get_mmc_clk() etc. and use generic functions instead.
>>>>>
>>>>
>>>> I know, but current codes are wrong, so first i want to correct it even
>>>> if it is old way because it's really easy. And then we can go to generic
>>>> functions.
>>>
>>> So not remove the generic functions?
>>>
>>> Is it this line which is broken?
>>>
>>> clock_get_periph_rate(PERIPH_ID_PWM0);
>>>
>>> If so, it seems like everything else uses its own function. It should
>>> all move easily to the generic function I think.
>>>
>>
>> The basic problem is the generic function is wrong.
> 
> Oh dear, does it not work for anything?

I have posted the patch relevant to this. I removed the generic peripheral clock API.
It's not used anywhere. Just get clock for pwm0.

how about?

https://patchwork.ozlabs.org/patch/426535/

Best Regards,
Jaehoon Chung
> 
> Regards,
> Simon
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