2020-05-01 13:49:32

by Colin King

[permalink] [raw]
Subject: [PATCH] net: dsa: sja1105: fix speed setting for 10 MBPS

From: Colin Ian King <[email protected]>

The current logic for speed checking will never set the speed to 10 MBPS
because bmcr & BMCR_SPEED10 is always 0 since BMCR_SPEED10 is 0. Also
the erroneous setting where BMCR_SPEED1000 and BMCR_SPEED100 are both
set causes the speed to be 1000 MBS. Fix this by masking bps and checking
for just the expected settings of BMCR_SPEED1000, BMCR_SPEED100 and
BMCR_SPEED10 and defaulting to the unknown speed otherwise.

Addresses-Coverity: ("Logically dead code")
Fixes: ffe10e679cec ("net: dsa: sja1105: Add support for the SGMII port")
Signed-off-by: Colin Ian King <[email protected]>
---
drivers/net/dsa/sja1105/sja1105_main.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c
index 472f4eb20c49..59a9038cdc4e 100644
--- a/drivers/net/dsa/sja1105/sja1105_main.c
+++ b/drivers/net/dsa/sja1105/sja1105_main.c
@@ -1600,6 +1600,7 @@ static const char * const sja1105_reset_reasons[] = {
int sja1105_static_config_reload(struct sja1105_private *priv,
enum sja1105_reset_reason reason)
{
+ const int mask = (BMCR_SPEED1000 | BMCR_SPEED100 | BMCR_SPEED10);
struct ptp_system_timestamp ptp_sts_before;
struct ptp_system_timestamp ptp_sts_after;
struct sja1105_mac_config_entry *mac;
@@ -1684,14 +1685,16 @@ int sja1105_static_config_reload(struct sja1105_private *priv,
sja1105_sgmii_pcs_config(priv, an_enabled, false);

if (!an_enabled) {
- int speed = SPEED_UNKNOWN;
+ int speed;

- if (bmcr & BMCR_SPEED1000)
+ if ((bmcr & mask) == BMCR_SPEED1000)
speed = SPEED_1000;
- else if (bmcr & BMCR_SPEED100)
+ else if ((bmcr & mask) == BMCR_SPEED100)
speed = SPEED_100;
- else if (bmcr & BMCR_SPEED10)
+ else if ((bmcr & mask) == BMCR_SPEED10)
speed = SPEED_10;
+ else
+ speed = SPEED_UNKNOWN;

sja1105_sgmii_pcs_force_speed(priv, speed);
}
--
2.25.1


2020-05-01 18:02:53

by walter harms

[permalink] [raw]
Subject: AW: [PATCH] net: dsa: sja1105: fix speed setting for 10 MBPS

IMHO it would be better to use switch case here to improve readability.

switch (bmcr & mask) {

case BMCR_SPEED1000:
speed = SPEED_1000;
break;
case BMCR_SPEED100:
speed = SPEED_100;
break;
case BMCR_SPEED10:
speed = SPEED_10;
break;
default:
speed = SPEED_UNKNOWN
}

jm2c,
wh

btw: an_enabled ? why not !enabled, mich more easy to read


________________________________________
Von: [email protected] <[email protected]> im Auftrag von Colin King <[email protected]>
Gesendet: Freitag, 1. Mai 2020 15:43:10
An: Vladimir Oltean; Andrew Lunn; Vivien Didelot; Florian Fainelli; David S . Miller; Russell King; [email protected]
Cc: [email protected]; [email protected]
Betreff: [PATCH] net: dsa: sja1105: fix speed setting for 10 MBPS

From: Colin Ian King <[email protected]>

The current logic for speed checking will never set the speed to 10 MBPS
because bmcr & BMCR_SPEED10 is always 0 since BMCR_SPEED10 is 0. Also
the erroneous setting where BMCR_SPEED1000 and BMCR_SPEED100 are both
set causes the speed to be 1000 MBS. Fix this by masking bps and checking
for just the expected settings of BMCR_SPEED1000, BMCR_SPEED100 and
BMCR_SPEED10 and defaulting to the unknown speed otherwise.

Addresses-Coverity: ("Logically dead code")
Fixes: ffe10e679cec ("net: dsa: sja1105: Add support for the SGMII port")
Signed-off-by: Colin Ian King <[email protected]>
---
drivers/net/dsa/sja1105/sja1105_main.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c
index 472f4eb20c49..59a9038cdc4e 100644
--- a/drivers/net/dsa/sja1105/sja1105_main.c
+++ b/drivers/net/dsa/sja1105/sja1105_main.c
@@ -1600,6 +1600,7 @@ static const char * const sja1105_reset_reasons[] = {
int sja1105_static_config_reload(struct sja1105_private *priv,
enum sja1105_reset_reason reason)
{
+ const int mask = (BMCR_SPEED1000 | BMCR_SPEED100 | BMCR_SPEED10);
struct ptp_system_timestamp ptp_sts_before;
struct ptp_system_timestamp ptp_sts_after;
struct sja1105_mac_config_entry *mac;
@@ -1684,14 +1685,16 @@ int sja1105_static_config_reload(struct sja1105_private *priv,
sja1105_sgmii_pcs_config(priv, an_enabled, false);

if (!an_enabled) {
- int speed = SPEED_UNKNOWN;
+ int speed;

- if (bmcr & BMCR_SPEED1000)
+ if ((bmcr & mask) == BMCR_SPEED1000)
speed = SPEED_1000;
- else if (bmcr & BMCR_SPEED100)
+ else if ((bmcr & mask) == BMCR_SPEED100)
speed = SPEED_100;
- else if (bmcr & BMCR_SPEED10)
+ else if ((bmcr & mask) == BMCR_SPEED10)
speed = SPEED_10;
+ else
+ speed = SPEED_UNKNOWN;

sja1105_sgmii_pcs_force_speed(priv, speed);
}
--
2.25.1

2020-05-01 18:39:10

by Russell King (Oracle)

[permalink] [raw]
Subject: Re: [PATCH] net: dsa: sja1105: fix speed setting for 10 MBPS

On Fri, May 01, 2020 at 06:00:52PM +0000, Walter Harms wrote:
> IMHO it would be better to use switch case here to improve readability.
>
> switch (bmcr & mask) {
>
> case BMCR_SPEED1000:
> speed = SPEED_1000;
> break;
> case BMCR_SPEED100:
> speed = SPEED_100;
> break;
> case BMCR_SPEED10:
> speed = SPEED_10;
> break;
> default:
> speed = SPEED_UNKNOWN
> }
>
> jm2c,
> wh
>
> btw: an_enabled ? why not !enabled, mich more easy to read

You misinterpret "an_enabled". It's not "negated enabled". It's not
even "disabled". It's short for "autonegotiation enabled". It's
positive logic too.

--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 10.2Mbps down 587kbps up

2020-05-02 12:23:23

by Sergei Shtylyov

[permalink] [raw]
Subject: Re: [PATCH] net: dsa: sja1105: fix speed setting for 10 MBPS

Hello!

On 01.05.2020 16:43, Colin King wrote:

> From: Colin Ian King <[email protected]>
>
> The current logic for speed checking will never set the speed to 10 MBPS
> because bmcr & BMCR_SPEED10 is always 0 since BMCR_SPEED10 is 0. Also
> the erroneous setting where BMCR_SPEED1000 and BMCR_SPEED100 are both
> set causes the speed to be 1000 MBS. Fix this by masking bps and checking
> for just the expected settings of BMCR_SPEED1000, BMCR_SPEED100 and
> BMCR_SPEED10 and defaulting to the unknown speed otherwise.
>
> Addresses-Coverity: ("Logically dead code")
> Fixes: ffe10e679cec ("net: dsa: sja1105: Add support for the SGMII port")
> Signed-off-by: Colin Ian King <[email protected]>
> ---
> drivers/net/dsa/sja1105/sja1105_main.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c
> index 472f4eb20c49..59a9038cdc4e 100644
> --- a/drivers/net/dsa/sja1105/sja1105_main.c
> +++ b/drivers/net/dsa/sja1105/sja1105_main.c
> @@ -1600,6 +1600,7 @@ static const char * const sja1105_reset_reasons[] = {
> int sja1105_static_config_reload(struct sja1105_private *priv,
> enum sja1105_reset_reason reason)
> {
> + const int mask = (BMCR_SPEED1000 | BMCR_SPEED100 | BMCR_SPEED10);

Why not declare it in the block it's used in? Also, () not needed here.

> struct ptp_system_timestamp ptp_sts_before;
> struct ptp_system_timestamp ptp_sts_after;
> struct sja1105_mac_config_entry *mac;
> @@ -1684,14 +1685,16 @@ int sja1105_static_config_reload(struct sja1105_private *priv,
> sja1105_sgmii_pcs_config(priv, an_enabled, false);
>
> if (!an_enabled) {
> - int speed = SPEED_UNKNOWN;
> + int speed;

Why not the following?

int mask = bmcr & (BMCR_SPEED1000 | BMCR_SPEED100 |
BMCR_SPEED10);

>
> - if (bmcr & BMCR_SPEED1000)
> + if ((bmcr & mask) == BMCR_SPEED1000)
> speed = SPEED_1000;
> - else if (bmcr & BMCR_SPEED100)
> + else if ((bmcr & mask) == BMCR_SPEED100)
> speed = SPEED_100;
> - else if (bmcr & BMCR_SPEED10)
> + else if ((bmcr & mask) == BMCR_SPEED10)
> speed = SPEED_10;
> + else
> + speed = SPEED_UNKNOWN;
>
> sja1105_sgmii_pcs_force_speed(priv, speed);
> }

MBR, Sergei