netdev - [PATCH net-next 07/17] net: sfp: avoid power switch on address-change modules

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <E1iTnrY-0005AQ-5o@rmk-PC.armlinux.org.uk>
Date:   Sun, 10 Nov 2019 14:06:44 +0000
From:   Russell King <rmk+kernel@...linux.org.uk>
To:     Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        Heiner Kallweit <hkallweit1@...il.com>
Cc:     "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org
Subject: [PATCH net-next 07/17] net: sfp: avoid power switch on address-change
 modules

If the module indicates that it requires an address change sequence to
switch between address 0x50 and 0x51, which we don't support, we can't
write to the register that controls the power mode to switch to high
power mode.  Warn the user that the module may not be functional in
this case, and don't try to change the power mode.

Signed-off-by: Russell King <rmk+kernel@...linux.org.uk>
---
 drivers/net/phy/sfp.c | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
index b105bbe7720a..7accd24a6875 100644
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -1322,25 +1322,34 @@ static int sfp_module_parse_power(struct sfp *sfp)
 	if (sfp->id.ext.options & cpu_to_be16(SFP_OPTIONS_HIGH_POWER_LEVEL))
 		power_mW = 2000;
 
-	if (sfp->id.ext.sff8472_compliance == SFP_SFF8472_COMPLIANCE_NONE &&
-	    (sfp->id.ext.diagmon & (SFP_DIAGMON_DDM | SFP_DIAGMON_ADDRMODE)) !=
-	    SFP_DIAGMON_DDM) {
-		/* The module appears not to implement bus address 0xa2,
-		 * or requires an address change sequence, so assume that
-		 * the module powers up in the indicated power mode.
-		 */
-		if (power_mW > sfp->max_power_mW) {
+	if (power_mW > sfp->max_power_mW) {
+		/* Module power specification exceeds the allowed maximum. */
+		if (sfp->id.ext.sff8472_compliance ==
+			SFP_SFF8472_COMPLIANCE_NONE &&
+		    !(sfp->id.ext.diagmon & SFP_DIAGMON_DDM)) {
+			/* The module appears not to implement bus address
+			 * 0xa2, so assume that the module powers up in the
+			 * indicated mode.
+			 */
 			dev_err(sfp->dev,
 				"Host does not support %u.%uW modules\n",
 				power_mW / 1000, (power_mW / 100) % 10);
 			return -EINVAL;
+		} else {
+			dev_warn(sfp->dev,
+				 "Host does not support %u.%uW modules, module left in power mode 1\n",
+				 power_mW / 1000, (power_mW / 100) % 10);
+			return 0;
 		}
-		return 0;
 	}
 
-	if (power_mW > sfp->max_power_mW) {
+	/* If the module requires a higher power mode, but also requires
+	 * an address change sequence, warn the user that the module may
+	 * not be functional.
+	 */
+	if (sfp->id.ext.diagmon & SFP_DIAGMON_ADDRMODE && power_mW > 1000) {
 		dev_warn(sfp->dev,
-			 "Host does not support %u.%uW modules, module left in power mode 1\n",
+			 "Address Change Sequence not supported but module requies %u.%uW, module may not be functional\n",
 			 power_mW / 1000, (power_mW / 100) % 10);
 		return 0;
 	}
-- 
2.20.1