cxgb4: fix eeprom len when diagnostics not implemented

Ensure diagnostics monitoring support is implemented for the SFF 8472
compliant port module and set the correct length for ethtool port
module eeprom read.

Fixes: f56ec676 ("cxgb4: Add support for ethtool i2c dump")
Signed-off-by: Manoj Malviya <manojmalviya@chelsio.com>
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/chelsio/cxgb4/cxgb4_ethtool.c

@@ -2015,12 +2015,15 @@ static int cxgb4_get_module_info(struct net_device *dev,
 		if (ret)
 			return ret;
 
-		if (!sff8472_comp || (sff_diag_type & 4)) {
+		if (!sff8472_comp || (sff_diag_type & SFP_DIAG_ADDRMODE)) {
 			modinfo->type = ETH_MODULE_SFF_8079;
 			modinfo->eeprom_len = ETH_MODULE_SFF_8079_LEN;
 		} else {
 			modinfo->type = ETH_MODULE_SFF_8472;
-			modinfo->eeprom_len = ETH_MODULE_SFF_8472_LEN;
+			if (sff_diag_type & SFP_DIAG_IMPLEMENTED)
+				modinfo->eeprom_len = ETH_MODULE_SFF_8472_LEN;
+			else
+				modinfo->eeprom_len = ETH_MODULE_SFF_8472_LEN / 2;
 		}
 		break;
 

drivers/net/ethernet/chelsio/cxgb4/t4_hw.h

@@ -293,6 +293,8 @@ enum {
 #define I2C_PAGE_SIZE		0x100
 #define SFP_DIAG_TYPE_ADDR	0x5c
 #define SFP_DIAG_TYPE_LEN	0x1
+#define SFP_DIAG_ADDRMODE	BIT(2)
+#define SFP_DIAG_IMPLEMENTED	BIT(6)
 #define SFF_8472_COMP_ADDR	0x5e
 #define SFF_8472_COMP_LEN	0x1
 #define SFF_REV_ADDR		0x1