linux-kernel - Re: [PATCH] bcma: Replace mdelay with usleep_range in bcma_pmu_resources

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Date:   Fri, 26 Jan 2018 10:27:12 -0600
From:   Larry Finger <Larry.Finger@...inger.net>
To:     Kalle Valo <kvalo@...eaurora.org>,
        Jia-Ju Bai <baijiaju1990@...il.com>
Cc:     zajec5@...il.com, hauke@...ke-m.de, linux-wireless@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] bcma: Replace mdelay with usleep_range in
 bcma_pmu_resources_init

On 01/26/2018 10:13 AM, Kalle Valo wrote:
> Jia-Ju Bai <baijiaju1990@...il.com> writes:
> 
>> After checking all possible call chains to bcma_pmu_resources_init() here,
>> my tool finds that this function is never called in atomic context,
>> namely never in an interrupt handler or holding a spinlock.
>> Thus mdelay can be replaced with usleep_range to avoid busy wait.
>>
>> This is found by a static analysis tool named DCNS written by myself.
>>
>> Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com>
>> ---
>>   drivers/bcma/driver_chipcommon_pmu.c |    2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/bcma/driver_chipcommon_pmu.c b/drivers/bcma/driver_chipcommon_pmu.c
>> index f1eb4d3..478948c 100644
>> --- a/drivers/bcma/driver_chipcommon_pmu.c
>> +++ b/drivers/bcma/driver_chipcommon_pmu.c
>> @@ -203,7 +203,7 @@ static void bcma_pmu_resources_init(struct bcma_drv_cc *cc)
>>   	 * Add some delay; allow resources to come up and settle.
>>   	 * Delay is required for SoC (early init).
>>   	 */
>> -	mdelay(2);
>> +	usleep_range(1500, 2000);
> 
> I would like to have an ack from someone familiar with bcma before I
> apply this.

No ack for this one.

Larry