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

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Message-ID: <9018be0b7dc441cd8aad625c6cc44e1c@bfs.de>
Date:   Fri, 1 May 2020 18:00:52 +0000
From:   Walter Harms <wharms@....de>
To:     Colin King <colin.king@...onical.com>,
        Vladimir Oltean <olteanv@...il.com>,
        Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        "David S . Miller" <davem@...emloft.net>,
        Russell King <rmk+kernel@...linux.org.uk>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     "kernel-janitors@...r.kernel.org" <kernel-janitors@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
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: kernel-janitors-owner@...r.kernel.org <kernel-janitors-owner@...r.kernel.org> im Auftrag von Colin King <colin.king@...onical.com>
Gesendet: Freitag, 1. Mai 2020 15:43:10
An: Vladimir Oltean; Andrew Lunn; Vivien Didelot; Florian Fainelli; David S . Miller; Russell King; linux-kernel@...r.kernel.org
Cc: kernel-janitors@...r.kernel.org; netdev@...r.kernel.org
Betreff: [PATCH] net: dsa: sja1105: fix speed setting for 10 MBPS

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

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 <colin.king@...onical.com>
---
 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