* [PATCH] staging/comedi: fix sparse warning: shift too big
@ 2014-05-02 14:57 Brilliantov Kirill Vladimirovich
2014-05-02 16:49 ` Ian Abbott
2014-05-03 23:58 ` Greg Kroah-Hartman
0 siblings, 2 replies; 6+ messages in thread
From: Brilliantov Kirill Vladimirovich @ 2014-05-02 14:57 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: Ian Abbott, H Hartley Sweeten, linux-kernel,
Brilliantov Kirill Vladimirovich
Signed-off-by: Brilliantov Kirill Vladimirovich <brilliantov@inbox.ru>
---
drivers/staging/comedi/drivers/ni_stc.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/staging/comedi/drivers/ni_stc.h b/drivers/staging/comedi/drivers/ni_stc.h
index f0630b78..197b568 100644
--- a/drivers/staging/comedi/drivers/ni_stc.h
+++ b/drivers/staging/comedi/drivers/ni_stc.h
@@ -717,7 +717,7 @@ enum AI_AO_Select_Bits {
static inline unsigned ni_stc_dma_channel_select_bitfield(unsigned channel)
{
if (channel < 4)
- return 1 << channel;
+ return 1 << (channel & 0x3);
if (channel == 4)
return 0x3;
if (channel == 5)
--
1.9.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] staging/comedi: fix sparse warning: shift too big
2014-05-02 14:57 [PATCH] staging/comedi: fix sparse warning: shift too big Brilliantov Kirill Vladimirovich
@ 2014-05-02 16:49 ` Ian Abbott
2014-05-02 18:28 ` Hartley Sweeten
2014-05-03 23:58 ` Greg Kroah-Hartman
1 sibling, 1 reply; 6+ messages in thread
From: Ian Abbott @ 2014-05-02 16:49 UTC (permalink / raw)
To: Brilliantov Kirill Vladimirovich, Greg Kroah-Hartman
Cc: H Hartley Sweeten, linux-kernel
On 2014-05-02 15:57, Brilliantov Kirill Vladimirovich wrote:
> Signed-off-by: Brilliantov Kirill Vladimirovich <brilliantov@inbox.ru>
> ---
> drivers/staging/comedi/drivers/ni_stc.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/staging/comedi/drivers/ni_stc.h b/drivers/staging/comedi/drivers/ni_stc.h
> index f0630b78..197b568 100644
> --- a/drivers/staging/comedi/drivers/ni_stc.h
> +++ b/drivers/staging/comedi/drivers/ni_stc.h
> @@ -717,7 +717,7 @@ enum AI_AO_Select_Bits {
> static inline unsigned ni_stc_dma_channel_select_bitfield(unsigned channel)
> {
> if (channel < 4)
> - return 1 << channel;
> + return 1 << (channel & 0x3);
> if (channel == 4)
> return 0x3;
> if (channel == 5)
>
The warning seems a bit spurious!
--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@mev.co.uk> )=-
-=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
^ permalink raw reply [flat|nested] 6+ messages in thread* RE: [PATCH] staging/comedi: fix sparse warning: shift too big
2014-05-02 16:49 ` Ian Abbott
@ 2014-05-02 18:28 ` Hartley Sweeten
2014-05-02 20:24 ` Ian Abbott
0 siblings, 1 reply; 6+ messages in thread
From: Hartley Sweeten @ 2014-05-02 18:28 UTC (permalink / raw)
To: Ian Abbott, Brilliantov Kirill Vladimirovich, Greg Kroah-Hartman
Cc: linux-kernel@vger.kernel.org
On Friday, May 02, 2014 9:50 AM, Ian Abbott wrote:
> On 2014-05-02 15:57, Brilliantov Kirill Vladimirovich wrote:
>> Signed-off-by: Brilliantov Kirill Vladimirovich <brilliantov@inbox.ru>
>> ---
>> drivers/staging/comedi/drivers/ni_stc.h | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/staging/comedi/drivers/ni_stc.h b/drivers/staging/comedi/drivers/ni_stc.h
>> index f0630b78..197b568 100644
>> --- a/drivers/staging/comedi/drivers/ni_stc.h
>> +++ b/drivers/staging/comedi/drivers/ni_stc.h
>> @@ -717,7 +717,7 @@ enum AI_AO_Select_Bits {
>> static inline unsigned ni_stc_dma_channel_select_bitfield(unsigned channel)
>> {
>> if (channel < 4)
>> - return 1 << channel;
>> + return 1 << (channel & 0x3);
>> if (channel == 4)
>> return 0x3;
>> if (channel == 5)
>>
>
> The warning seems a bit spurious!
The whole mite.c driver and it's users are all a bit of a mess.
I did find the information about the "AI AO Select Register" in the National
Instruments PCI E Series manual:
-----
The AI AO Select Register contains 8 bits that control the logical DMA selection for the
analog input and analog output resources. The contents of this register are cleared upon power
up and after a reset condition.
Address: base address + 0x09
Type: write-only
Word size: 8-bit
Bit Name Description
7-4 Reserved Reserved-Always write 0 to these bits (for PCI-6032E
and PCI-6033E only).
7-4 Output<D..A> Analog Output Logical Channel D through A-These four
bits select the logical channels of the MITE to be used by
the analog output. You can only set one of these bits at a
time (except for the PCI-6032E and PCI-6033E).
3-0 Input<D..A> Analog Input Logical Channel D through A-These four
bits select the logical channels to be used by the analog
input. You can only set one of these bits at a time.
-----
Based on this the ni_stc_dma_channel_select_bitfield() function appears to be
incorrect. The "channel"s should only be in the range 0 to 3 and result in a returned
bitfield of:
channel bitfield Description
0 0x01 Analog Input or Output Channel A
1 0x02 Analog Input or Output Channel B
2 0x04 Analog Input or Output Channel C
3 0x08 Analog Input or Output Channel D
Just my two cents...
Hartley
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] staging/comedi: fix sparse warning: shift too big
2014-05-02 18:28 ` Hartley Sweeten
@ 2014-05-02 20:24 ` Ian Abbott
0 siblings, 0 replies; 6+ messages in thread
From: Ian Abbott @ 2014-05-02 20:24 UTC (permalink / raw)
To: Hartley Sweeten, Brilliantov Kirill Vladimirovich,
Greg Kroah-Hartman
Cc: linux-kernel@vger.kernel.org
On 02/05/14 19:28, Hartley Sweeten wrote:
> On Friday, May 02, 2014 9:50 AM, Ian Abbott wrote:
>> On 2014-05-02 15:57, Brilliantov Kirill Vladimirovich wrote:
>>> Signed-off-by: Brilliantov Kirill Vladimirovich <brilliantov@inbox.ru>
>>> ---
>>> drivers/staging/comedi/drivers/ni_stc.h | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/staging/comedi/drivers/ni_stc.h b/drivers/staging/comedi/drivers/ni_stc.h
>>> index f0630b78..197b568 100644
>>> --- a/drivers/staging/comedi/drivers/ni_stc.h
>>> +++ b/drivers/staging/comedi/drivers/ni_stc.h
>>> @@ -717,7 +717,7 @@ enum AI_AO_Select_Bits {
>>> static inline unsigned ni_stc_dma_channel_select_bitfield(unsigned channel)
>>> {
>>> if (channel < 4)
>>> - return 1 << channel;
>>> + return 1 << (channel & 0x3);
>>> if (channel == 4)
>>> return 0x3;
>>> if (channel == 5)
>>>
>>
>> The warning seems a bit spurious!
>
> The whole mite.c driver and it's users are all a bit of a mess.
>
> I did find the information about the "AI AO Select Register" in the National
> Instruments PCI E Series manual:
>
> -----
>
> The AI AO Select Register contains 8 bits that control the logical DMA selection for the
> analog input and analog output resources. The contents of this register are cleared upon power
> up and after a reset condition.
> Address: base address + 0x09
> Type: write-only
> Word size: 8-bit
>
> Bit Name Description
> 7-4 Reserved Reserved-Always write 0 to these bits (for PCI-6032E
> and PCI-6033E only).
> 7-4 Output<D..A> Analog Output Logical Channel D through A-These four
> bits select the logical channels of the MITE to be used by
> the analog output. You can only set one of these bits at a
> time (except for the PCI-6032E and PCI-6033E).
> 3-0 Input<D..A> Analog Input Logical Channel D through A-These four
> bits select the logical channels to be used by the analog
> input. You can only set one of these bits at a time.
>
> -----
>
> Based on this the ni_stc_dma_channel_select_bitfield() function appears to be
> incorrect. The "channel"s should only be in the range 0 to 3 and result in a returned
> bitfield of:
>
> channel bitfield Description
> 0 0x01 Analog Input or Output Channel A
> 1 0x02 Analog Input or Output Channel B
> 2 0x04 Analog Input or Output Channel C
> 3 0x08 Analog Input or Output Channel D
>
> Just my two cents...
Apparently, the M-series cards have six DMA channels - two more than the
E-series cards. They must have decided to keep the existing bitfield
encoding for the first four channels for backwards compatibility, and
use special bitfield values for the extra channels.
--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@mev.co.uk> )=-
-=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] staging/comedi: fix sparse warning: shift too big
2014-05-02 14:57 [PATCH] staging/comedi: fix sparse warning: shift too big Brilliantov Kirill Vladimirovich
2014-05-02 16:49 ` Ian Abbott
@ 2014-05-03 23:58 ` Greg Kroah-Hartman
2014-05-04 7:46 ` Brilliantov Kirill Vladimirovich
1 sibling, 1 reply; 6+ messages in thread
From: Greg Kroah-Hartman @ 2014-05-03 23:58 UTC (permalink / raw)
To: Brilliantov Kirill Vladimirovich
Cc: Ian Abbott, H Hartley Sweeten, linux-kernel
On Fri, May 02, 2014 at 06:57:04PM +0400, Brilliantov Kirill Vladimirovich wrote:
> Signed-off-by: Brilliantov Kirill Vladimirovich <brilliantov@inbox.ru>
> ---
> drivers/staging/comedi/drivers/ni_stc.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/staging/comedi/drivers/ni_stc.h b/drivers/staging/comedi/drivers/ni_stc.h
> index f0630b78..197b568 100644
> --- a/drivers/staging/comedi/drivers/ni_stc.h
> +++ b/drivers/staging/comedi/drivers/ni_stc.h
> @@ -717,7 +717,7 @@ enum AI_AO_Select_Bits {
> static inline unsigned ni_stc_dma_channel_select_bitfield(unsigned channel)
> {
> if (channel < 4)
> - return 1 << channel;
> + return 1 << (channel & 0x3);
That change does nothing, so it's not worth applying, don't you agree?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 6+ messages in thread
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2014-05-02 14:57 [PATCH] staging/comedi: fix sparse warning: shift too big Brilliantov Kirill Vladimirovich
2014-05-02 16:49 ` Ian Abbott
2014-05-02 18:28 ` Hartley Sweeten
2014-05-02 20:24 ` Ian Abbott
2014-05-03 23:58 ` Greg Kroah-Hartman
2014-05-04 7:46 ` Brilliantov Kirill Vladimirovich
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