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

Subsystems: networking drivers, networking [dsa], the rest

STALE2284d

4 messages, 4 authors, 2020-05-02 · open the first message on its own page

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

From: Colin King <hidden>
Date: 2020-05-01 13:47:44

From: Colin Ian King <redacted>

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 <redacted>
---
 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

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

From: Walter Harms <hidden>
Date: 2020-05-01 18:00:57

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: kernel-janitors-owner@vger.kernel.org [off-list ref] im Auftrag von Colin King [off-list ref]
Gesendet: Freitag, 1. Mai 2020 15:43:10
An: Vladimir Oltean; Andrew Lunn; Vivien Didelot; Florian Fainelli; David S . Miller; Russell King; linux-kernel@vger.kernel.org
Cc: kernel-janitors@vger.kernel.org; netdev@vger.kernel.org
Betreff: [PATCH] net: dsa: sja1105: fix speed setting for 10 MBPS

From: Colin Ian King <redacted>

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 <redacted>
---
 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

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

From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Date: 2020-05-01 18:37:28

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

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

From: Sergei Shtylyov <hidden>
Date: 2020-05-02 12:21:28

Hello!

On 01.05.2020 16:43, Colin King wrote:
quoted hunk
From: Colin Ian King <redacted>

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 <redacted>
---
  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.
quoted hunk
  	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
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