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[1/8] memory: emif: Correct the lpmode timeout calculation

Message ID 1362978365-5593-2-git-send-email-lokeshvutla@ti.com (mailing list archive)
State New, archived
Headers show

Commit Message

Lokesh Vutla March 11, 2013, 5:05 a.m. UTC
The driver tries to round up the specified timeout cycles to
the next power of 2 value. But this is done wrongly.
Correcting this here.

Reported-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
---
 drivers/memory/emif.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Santosh Shilimkar March 11, 2013, 5:34 a.m. UTC | #1
minor nit.
$subject
s/Correct/Fix

On Monday 11 March 2013 10:35 AM, Lokesh Vutla wrote:
> The driver tries to round up the specified timeout cycles to
> the next power of 2 value. But this is done wrongly.
> Correcting this here.
>
Change needs to be improved here. See below.
 
> Reported-by: Nishanth Menon <nm@ti.com>
> Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
> ---
>  drivers/memory/emif.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/memory/emif.c b/drivers/memory/emif.c
> index df08736..622638c 100644
> --- a/drivers/memory/emif.c
> +++ b/drivers/memory/emif.c
> @@ -732,9 +732,9 @@ static u32 get_pwr_mgmt_ctrl(u32 freq, struct emif_data *emif, u32 ip_rev)
>  	if (timeout < 16) {
>  		timeout = 0;
>  	} else {
> -		timeout = __fls(timeout) - 3;
>  		if (timeout & (timeout - 1))
So from the change, it appears that, the timeout
check for power of 2 should be done before updating
the variable which seems to be the right fix.

> -			timeout++;
> +			timeout <<= 1;
> +		timeout = __fls(timeout) - 3;
>  	}
>  
>  	switch (lpmode) {
> 
So just make changelog verbose as well as add a
comment about the calculation in the code.

Otherwise, patch looks fine to me.
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
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diff mbox

Patch

diff --git a/drivers/memory/emif.c b/drivers/memory/emif.c
index df08736..622638c 100644
--- a/drivers/memory/emif.c
+++ b/drivers/memory/emif.c
@@ -732,9 +732,9 @@  static u32 get_pwr_mgmt_ctrl(u32 freq, struct emif_data *emif, u32 ip_rev)
 	if (timeout < 16) {
 		timeout = 0;
 	} else {
-		timeout = __fls(timeout) - 3;
 		if (timeout & (timeout - 1))
-			timeout++;
+			timeout <<= 1;
+		timeout = __fls(timeout) - 3;
 	}
 
 	switch (lpmode) {