[PATCH] net: ethernet: sun: remove redundant variables adv and lpa

[PATCH] net: ethernet: sun: remove redundant variables adv and lpa

[Colin King]

From: Colin Ian King <colin.king@canonical.com>

Variables adv and lpa are being assigned but are never used hence they
are redundant and can be removed.

Cleans up clang warnings:
warning: variable 'lpa' set but not used [-Wunused-but-set-variable]
warning: variable 'adv' set but not used [-Wunused-but-set-variable]

Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/net/ethernet/sun/niu.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/net/ethernet/sun/niu.c b/drivers/net/ethernet/sun/niu.c
index 88c12474a0c3..2d6b62c6d9ab 100644
--- a/drivers/net/ethernet/sun/niu.c
+++ b/drivers/net/ethernet/sun/niu.c
@@ -1225,17 +1225,13 @@ static int link_status_1g_rgmii(struct niu *np, int *link_up_p)
 
 	bmsr = err;
 	if (bmsr & BMSR_LSTATUS) {
-		u16 adv, lpa;
-
 		err = mii_read(np, np->phy_addr, MII_ADVERTISE);
 		if (err < 0)
 			goto out;
-		adv = err;
 
 		err = mii_read(np, np->phy_addr, MII_LPA);
 		if (err < 0)
 			goto out;
-		lpa = err;
 
 		err = mii_read(np, np->phy_addr, MII_ESTATUS);
 		if (err < 0)
-- 
2.17.1

Re: [PATCH] net: ethernet: sun: remove redundant variables adv and lpa

[Dan Carpenter]

On Thu, Jul 05, 2018 at 10:37:32AM +0100, Colin King wrote:
> diff --git a/drivers/net/ethernet/sun/niu.c b/drivers/net/ethernet/sun/niu.c
> index 88c12474a0c3..2d6b62c6d9ab 100644
> --- a/drivers/net/ethernet/sun/niu.c
> +++ b/drivers/net/ethernet/sun/niu.c
> @@ -1225,17 +1225,13 @@ static int link_status_1g_rgmii(struct niu *np, int *link_up_p)
>  
>  	bmsr = err;
>  	if (bmsr & BMSR_LSTATUS) {
> -		u16 adv, lpa;
> -
>  		err = mii_read(np, np->phy_addr, MII_ADVERTISE);
>  		if (err < 0)
>  			goto out;
> -		adv = err;
>  
>  		err = mii_read(np, np->phy_addr, MII_LPA);
>  		if (err < 0)
>  			goto out;
> -		lpa = err;

I'm fairly sure we could get rid of the mii_read() calls as well.

regards,
dan carpenter

Re: [PATCH] net: ethernet: sun: remove redundant variables adv and lpa

[Colin Ian King]

On 05/07/18 10:52, Dan Carpenter wrote:
> On Thu, Jul 05, 2018 at 10:37:32AM +0100, Colin King wrote:
>> diff --git a/drivers/net/ethernet/sun/niu.c b/drivers/net/ethernet/sun/niu.c
>> index 88c12474a0c3..2d6b62c6d9ab 100644
>> --- a/drivers/net/ethernet/sun/niu.c
>> +++ b/drivers/net/ethernet/sun/niu.c
>> @@ -1225,17 +1225,13 @@ static int link_status_1g_rgmii(struct niu *np, int *link_up_p)
>>  
>>  	bmsr = err;
>>  	if (bmsr & BMSR_LSTATUS) {
>> -		u16 adv, lpa;
>> -
>>  		err = mii_read(np, np->phy_addr, MII_ADVERTISE);
>>  		if (err < 0)
>>  			goto out;
>> -		adv = err;
>>  
>>  		err = mii_read(np, np->phy_addr, MII_LPA);
>>  		if (err < 0)
>>  			goto out;
>> -		lpa = err;
> 
> I'm fairly sure we could get rid of the mii_read() calls as well.

I'm always concerned that removing the reads of H/W registers can affect
the behavior, so I left those in.

Colin

> 
> regards,
> dan carpenter
> 
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Re: [PATCH] net: ethernet: sun: remove redundant variables adv and lpa

[Dan Carpenter]

On Thu, Jul 05, 2018 at 10:54:51AM +0100, Colin Ian King wrote:
> On 05/07/18 10:52, Dan Carpenter wrote:
> > On Thu, Jul 05, 2018 at 10:37:32AM +0100, Colin King wrote:
> >> diff --git a/drivers/net/ethernet/sun/niu.c b/drivers/net/ethernet/sun/niu.c
> >> index 88c12474a0c3..2d6b62c6d9ab 100644
> >> --- a/drivers/net/ethernet/sun/niu.c
> >> +++ b/drivers/net/ethernet/sun/niu.c
> >> @@ -1225,17 +1225,13 @@ static int link_status_1g_rgmii(struct niu *np, int *link_up_p)
> >>  
> >>  	bmsr = err;
> >>  	if (bmsr & BMSR_LSTATUS) {
> >> -		u16 adv, lpa;
> >> -
> >>  		err = mii_read(np, np->phy_addr, MII_ADVERTISE);
> >>  		if (err < 0)
> >>  			goto out;
> >> -		adv = err;
> >>  
> >>  		err = mii_read(np, np->phy_addr, MII_LPA);
> >>  		if (err < 0)
> >>  			goto out;
> >> -		lpa = err;
> > 
> > I'm fairly sure we could get rid of the mii_read() calls as well.
> 
> I'm always concerned that removing the reads of H/W registers can affect
> the behavior, so I left those in.

Yeah...  That's true sometimes.  Hence my "fairly sure" equivocation.  I
looked to see if any of the original devs are around and it's been a
while since anyone worked on this driver.

When we remove these warnings it means that there is no chance that
someone will look at the code again and remove the unneeded mii_read()
calls.  I'm 90% sure the reads are unnecessary.

regards,
dan carpenter

Re: [PATCH] net: ethernet: sun: remove redundant variables adv and lpa

[David Miller]

From: Colin King <colin.king@canonical.com>
Date: Thu,  5 Jul 2018 10:37:32 +0100

> From: Colin Ian King <colin.king@canonical.com>
> 
> Variables adv and lpa are being assigned but are never used hence they
> are redundant and can be removed.
> 
> Cleans up clang warnings:
> warning: variable 'lpa' set but not used [-Wunused-but-set-variable]
> warning: variable 'adv' set but not used [-Wunused-but-set-variable]
> 
> Signed-off-by: Colin Ian King <colin.king@canonical.com>

I think you can safely remove the register reads too, so please
do so.

Thanks.

Re: [PATCH] net: ethernet: sun: remove redundant variables adv and lpa

[Colin Ian King]

On 05/07/18 11:33, David Miller wrote:
> From: Colin King <colin.king@canonical.com>
> Date: Thu,  5 Jul 2018 10:37:32 +0100
> 
>> From: Colin Ian King <colin.king@canonical.com>
>>
>> Variables adv and lpa are being assigned but are never used hence they
>> are redundant and can be removed.
>>
>> Cleans up clang warnings:
>> warning: variable 'lpa' set but not used [-Wunused-but-set-variable]
>> warning: variable 'adv' set but not used [-Wunused-but-set-variable]
>>
>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> 
> I think you can safely remove the register reads too, so please
> do so.

Just to clarify, just the MII_ADVERTISE and MII_LPA, or both these AND
also MII_ESTATUS too?

> 
> Thanks.
> 

Re: [PATCH] net: ethernet: sun: remove redundant variables adv and lpa

[David Miller]

From: Colin Ian King <colin.king@canonical.com>
Date: Thu, 5 Jul 2018 11:50:01 +0100

> Just to clarify, just the MII_ADVERTISE and MII_LPA, or both these AND
> also MII_ESTATUS too?

I think you can safely remove all three.

Re: [PATCH] net: ethernet: sun: remove redundant variables adv and lpa

[Andrew Lunn]

On Thu, Jul 05, 2018 at 10:37:32AM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Variables adv and lpa are being assigned but are never used hence they
> are redundant and can be removed.
> 
> Cleans up clang warnings:
> warning: variable 'lpa' set but not used [-Wunused-but-set-variable]
> warning: variable 'adv' set but not used [-Wunused-but-set-variable]
> 
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/net/ethernet/sun/niu.c | 4 ----
>  1 file changed, 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/sun/niu.c b/drivers/net/ethernet/sun/niu.c
> index 88c12474a0c3..2d6b62c6d9ab 100644
> --- a/drivers/net/ethernet/sun/niu.c
> +++ b/drivers/net/ethernet/sun/niu.c
> @@ -1225,17 +1225,13 @@ static int link_status_1g_rgmii(struct niu *np, int *link_up_p)
>  
>  	bmsr = err;
>  	if (bmsr & BMSR_LSTATUS) {
> -		u16 adv, lpa;
> -
>  		err = mii_read(np, np->phy_addr, MII_ADVERTISE);
>  		if (err < 0)
>  			goto out;
> -		adv = err;
>  
>  		err = mii_read(np, np->phy_addr, MII_LPA);
>  		if (err < 0)
>  			goto out;
> -		lpa = err;
>  
>  		err = mii_read(np, np->phy_addr, MII_ESTATUS);
>  		if (err < 0)

What should really happen is something like:

                common_adv = lpa & adv;

                lp->active_speed = SPEED_10;
                lp->active_duplex = DUPLEX_HALF;

                if (common_adv_gb & (LPA_1000FULL | LPA_1000HALF)) {
                        lp->active_speed = SPEED_1000;

                        if (common_adv_gb & LPA_1000FULL)
                                lp->active_duplex = DUPLEX_FULL;
                } else if (common_adv & (LPA_100FULL | LPA_100HALF)) {
                        lp->active_speed = SPEED_100;

                        if (common_adv & LPA_100FULL)
                                lp->active_duplex = DUPLEX_FULL;
                } else
                        if (common_adv & LPA_10FULL)
                                lp->active_duplex = DUPLEX_FULL;

i.e. making use of the results of the autoneg to determine the link
speed and duplex, rather than just assuming it is 1G.

If i turn this into a real patch, does anybody have the hardware to
test it?

      Andrew