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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        "Mauro S. M. Rodrigues" <maurosr@linux.vnet.ibm.com>,
        Jesse Brandeburg <jesse.brandeburg@intel.com>,
        Andrew Bowers <andrewx.bowers@intel.com>,
        Jeff Kirsher <jeffrey.t.kirsher@intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 048/158] ixgbe: Check DDM existence in transceiver before access
Date:   Fri,  2 Aug 2019 11:27:49 +0200
Message-Id: <20190802092213.808825843@linuxfoundation.org>
In-Reply-To: <20190802092203.671944552@linuxfoundation.org>
References: <20190802092203.671944552@linuxfoundation.org>
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[ Upstream commit 655c91414579d7bb115a4f7898ee726fc18e0984 ]

Some transceivers may comply with SFF-8472 but not implement the Digital
Diagnostic Monitoring (DDM) interface described in it. The existence of
such area is specified by bit 6 of byte 92, set to 1 if implemented.

Currently, due to not checking this bit ixgbe fails trying to read SFP
module's eeprom with the follow message:

ethtool -m enP51p1s0f0
Cannot get Module EEPROM data: Input/output error

Because it fails to read the additional 256 bytes in which it was assumed
to exist the DDM data.

This issue was noticed using a Mellanox Passive DAC PN 01FT738. The eeprom
data was confirmed by Mellanox as correct and present in other Passive
DACs in from other manufacturers.

Signed-off-by: "Mauro S. M. Rodrigues" <maurosr@linux.vnet.ibm.com>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c | 3 ++-
 drivers/net/ethernet/intel/ixgbe/ixgbe_phy.h     | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
index d681273bd39d..9d38634071a4 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
@@ -3133,7 +3133,8 @@ static int ixgbe_get_module_info(struct net_device *dev,
 		page_swap = true;
 	}
 
-	if (sff8472_rev == IXGBE_SFF_SFF_8472_UNSUP || page_swap) {
+	if (sff8472_rev == IXGBE_SFF_SFF_8472_UNSUP || page_swap ||
+	    !(addr_mode & IXGBE_SFF_DDM_IMPLEMENTED)) {
 		/* We have a SFP, but it does not support SFF-8472 */
 		modinfo->type = ETH_MODULE_SFF_8079;
 		modinfo->eeprom_len = ETH_MODULE_SFF_8079_LEN;
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.h b/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.h
index 5abd66c84d00..7b7dc6d7d159 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.h
@@ -70,6 +70,7 @@
 #define IXGBE_SFF_SOFT_RS_SELECT_10G		0x8
 #define IXGBE_SFF_SOFT_RS_SELECT_1G		0x0
 #define IXGBE_SFF_ADDRESSING_MODE		0x4
+#define IXGBE_SFF_DDM_IMPLEMENTED		0x40
 #define IXGBE_SFF_QSFP_DA_ACTIVE_CABLE		0x1
 #define IXGBE_SFF_QSFP_DA_PASSIVE_CABLE		0x8
 #define IXGBE_SFF_QSFP_CONNECTOR_NOT_SEPARABLE	0x23
-- 
2.20.1