From: Min Guo <[email protected]>
Remove unused 'devctl' variable to fix compile warnings:
drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
but not used [-Wunused-but-set-variable]
Signed-off-by: Min Guo <[email protected]>
---
changes in v3
suggested by Greg Kroah-Hartman:
Add a comment.
changes in v2
suggested by Alan Stern:
Add void before musb_read to indicate that the register MUSB_DEVCTL
was intended to be read and discarded.
---
drivers/usb/musb/musbhsdma.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
index 0aacfc8be5a1..2a345b4ad015 100644
--- a/drivers/usb/musb/musbhsdma.c
+++ b/drivers/usb/musb/musbhsdma.c
@@ -321,8 +321,6 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
musb_channel->channel.status =
MUSB_DMA_STATUS_BUS_ABORT;
} else {
- u8 devctl;
-
addr = musb_read_hsdma_addr(mbase,
bchannel);
channel->actual_len = addr
@@ -336,7 +334,11 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
< musb_channel->len) ?
"=> reconfig 0" : "=> complete");
- devctl = musb_readb(mbase, MUSB_DEVCTL);
+ /*
+ * Some hardware may need to read the
+ * MUSB_DEVCTL register once to take effect.
+ */
+ (void)musb_readb(mbase, MUSB_DEVCTL);
channel->status = MUSB_DMA_STATUS_FREE;
--
2.18.0
Hello!
On 24.11.2020 11:49, [email protected] wrote:
> From: Min Guo <[email protected]>
>
> Remove unused 'devctl' variable to fix compile warnings:
>
> drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
> drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
> but not used [-Wunused-but-set-variable]
>
> Signed-off-by: Min Guo <[email protected]>
> ---
> changes in v3
> suggested by Greg Kroah-Hartman:
> Add a comment.
>
> changes in v2
> suggested by Alan Stern:
> Add void before musb_read to indicate that the register MUSB_DEVCTL
> was intended to be read and discarded.
> ---
> drivers/usb/musb/musbhsdma.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
> index 0aacfc8be5a1..2a345b4ad015 100644
> --- a/drivers/usb/musb/musbhsdma.c
> +++ b/drivers/usb/musb/musbhsdma.c
[...]
> @@ -336,7 +334,11 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> < musb_channel->len) ?
> "=> reconfig 0" : "=> complete");
>
> - devctl = musb_readb(mbase, MUSB_DEVCTL);
> + /*
> + * Some hardware may need to read the
> + * MUSB_DEVCTL register once to take effect.
> + */
> + (void)musb_readb(mbase, MUSB_DEVCTL);
Hm, forcibly reading DevCtl in the DMA driver... sounds quite
nonsensically. Lemme take a look...
[...]
MBR, Sergei
On 11/24/20 12:13 PM, Sergei Shtylyov wrote:
[...]
>> From: Min Guo <[email protected]>
>>
>> Remove unused 'devctl' variable to fix compile warnings:
>>
>> drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
>> drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
>> but not used [-Wunused-but-set-variable]
>>
>> Signed-off-by: Min Guo <[email protected]>
>> ---
>> changes in v3
>> suggested by Greg Kroah-Hartman:
>> Add a comment.
>>
>> changes in v2
>> suggested by Alan Stern:
>> Add void before musb_read to indicate that the register MUSB_DEVCTL
>> was intended to be read and discarded.
>> ---
>> drivers/usb/musb/musbhsdma.c | 8 +++++---
>> 1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
>> index 0aacfc8be5a1..2a345b4ad015 100644
>> --- a/drivers/usb/musb/musbhsdma.c
>> +++ b/drivers/usb/musb/musbhsdma.c
> [...]
>> @@ -336,7 +334,11 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
>> < musb_channel->len) ?
>> "=> reconfig 0" : "=> complete");
>> - devctl = musb_readb(mbase, MUSB_DEVCTL);
>> + /*
>> + * Some hardware may need to read the
>> + * MUSB_DEVCTL register once to take effect.
>> + */
>> + (void)musb_readb(mbase, MUSB_DEVCTL);
>
> Hm, forcibly reading DevCtl in the DMA driver... sounds quite nonsensically. Lemme take a look...
Indeed, prior to commit c418fd6c01fbc5516a2cd1eaf1df1ec86869028a ("usb: gadget: musb: fix short
isoc packets with inventra dma") the DevCtl read was done in order to check the DevCtl.HostMode bit --
this test was removed but the DevCtl read was left intact... so my vote goes for deleting both the
read and the variable...
> [...]
MBR, Sergei
On 12/10/20 6:01 PM, Greg Kroah-Hartman wrote:
[...]
>>> From: Min Guo <[email protected]>
>>>
>>> Remove unused 'devctl' variable to fix compile warnings:
>>>
>>> drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
>>> drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
>>> but not used [-Wunused-but-set-variable]
>>>
>>> Signed-off-by: Min Guo <[email protected]>
>>> ---
>>> changes in v3
>>> suggested by Greg Kroah-Hartman:
>>> Add a comment.
>>>
>>> changes in v2
>>> suggested by Alan Stern:
>>> Add void before musb_read to indicate that the register MUSB_DEVCTL
>>> was intended to be read and discarded.
>>> ---
>>> drivers/usb/musb/musbhsdma.c | 8 +++++---
>>> 1 file changed, 5 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
>>> index 0aacfc8be5a1..2a345b4ad015 100644
>>> --- a/drivers/usb/musb/musbhsdma.c
>>> +++ b/drivers/usb/musb/musbhsdma.c
>> [...]
>>> @@ -336,7 +334,11 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
>>> < musb_channel->len) ?
>>> "=> reconfig 0" : "=> complete");
>>> - devctl = musb_readb(mbase, MUSB_DEVCTL);
>>> + /*
>>> + * Some hardware may need to read the
>>> + * MUSB_DEVCTL register once to take effect.
>>> + */
>>> + (void)musb_readb(mbase, MUSB_DEVCTL);
>>
>> Hm, forcibly reading DevCtl in the DMA driver... sounds quite
>> nonsensically. Lemme take a look...
>
> What happened to your look?
I thought I posted it the same day... Indeed, here it is, archived:
https://marc.info/?l=linux-usb&m=160621841910477
> thanks,
>
> greg k-h
MBR, Sergei
On Tue, Nov 24, 2020 at 12:13:42PM +0300, Sergei Shtylyov wrote:
> Hello!
>
> On 24.11.2020 11:49, [email protected] wrote:
>
> > From: Min Guo <[email protected]>
> >
> > Remove unused 'devctl' variable to fix compile warnings:
> >
> > drivers/usb/musb/musbhsdma.c: In function 'dma_controller_irq':
> > drivers/usb/musb/musbhsdma.c:324:8: warning: variable 'devctl' set
> > but not used [-Wunused-but-set-variable]
> >
> > Signed-off-by: Min Guo <[email protected]>
> > ---
> > changes in v3
> > suggested by Greg Kroah-Hartman:
> > Add a comment.
> >
> > changes in v2
> > suggested by Alan Stern:
> > Add void before musb_read to indicate that the register MUSB_DEVCTL
> > was intended to be read and discarded.
> > ---
> > drivers/usb/musb/musbhsdma.c | 8 +++++---
> > 1 file changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
> > index 0aacfc8be5a1..2a345b4ad015 100644
> > --- a/drivers/usb/musb/musbhsdma.c
> > +++ b/drivers/usb/musb/musbhsdma.c
> [...]
> > @@ -336,7 +334,11 @@ irqreturn_t dma_controller_irq(int irq, void *private_data)
> > < musb_channel->len) ?
> > "=> reconfig 0" : "=> complete");
> > - devctl = musb_readb(mbase, MUSB_DEVCTL);
> > + /*
> > + * Some hardware may need to read the
> > + * MUSB_DEVCTL register once to take effect.
> > + */
> > + (void)musb_readb(mbase, MUSB_DEVCTL);
>
> Hm, forcibly reading DevCtl in the DMA driver... sounds quite
> nonsensically. Lemme take a look...
What happened to your look?
thanks,
greg k-h