Re: [PATCH] bcma: Replace mdelay with usleep_range in bcma_pmu_resources_init

From: Jia-Ju Bai
Date: Fri Jan 26 2018 - 11:34:17 EST




On 2018/1/27 0:26, Larry Finger wrote:
On 01/26/2018 03:13 AM, Jia-Ju Bai wrote:
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@xxxxxxxxx>
---
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 have no idea how critical this delay might be, but it would be safer to never make the sleep be shorter than the original delay. Using (2000, 2500) would be a better choice of arguments for usleep_range().

Okay, I have used usleep_range(2000, 2500) and sent patch v2.


Thanks,
Jia-Ju Bai