[etherfabric] Fix use of uninitialised variable in falcon_xaui_link_ok()

The link status check in falcon_xaui_link_ok() reads from the
FCN_XX_CORE_STAT_REG_MAC register only on production hardware (where
the FPGA version reads as zero), but modifies the value and writes
back to this register unconditionally.  This triggers an uninitialised
variable warning on newer versions of gcc.

Fix by assuming that the register exists only on production hardware,
and so moving the "modify-write" portion of the "read-modify-write"
operation to also be covered by the same conditional check.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/drivers/net/etherfabric.c b/src/drivers/net/etherfabric.c
index b40596beae753eb346256c791a7067235f07dd43..be30b71f79fd7f4e8eacdbb936e5981325cbdfcc 100644 (file)
--- a/src/drivers/net/etherfabric.c
+++ b/src/drivers/net/etherfabric.c
@@ -2225,13 +2225,16 @@ falcon_xaui_link_ok ( struct efab_nic *efab )
                sync = ( sync == FCN_XX_SYNC_STAT_DECODE_SYNCED );
                
                link_ok = align_done && sync;
-       }
 
-       /* Clear link status ready for next read */
-       EFAB_SET_DWORD_FIELD ( reg, FCN_XX_COMMA_DET, FCN_XX_COMMA_DET_RESET );
-       EFAB_SET_DWORD_FIELD ( reg, FCN_XX_CHARERR, FCN_XX_CHARERR_RESET);
-       EFAB_SET_DWORD_FIELD ( reg, FCN_XX_DISPERR, FCN_XX_DISPERR_RESET);
-       falcon_xmac_writel ( efab, &reg, FCN_XX_CORE_STAT_REG_MAC );
+               /* Clear link status ready for next read */
+               EFAB_SET_DWORD_FIELD ( reg, FCN_XX_COMMA_DET,
+                                      FCN_XX_COMMA_DET_RESET );
+               EFAB_SET_DWORD_FIELD ( reg, FCN_XX_CHARERR,
+                                      FCN_XX_CHARERR_RESET );
+               EFAB_SET_DWORD_FIELD ( reg, FCN_XX_DISPERR,
+                                      FCN_XX_DISPERR_RESET );
+               falcon_xmac_writel ( efab, &reg, FCN_XX_CORE_STAT_REG_MAC );
+       }
 
        has_phyxs = ( efab->phy_op->mmds & ( 1 << MDIO_MMD_PHYXS ) );
        if ( link_ok && has_phyxs ) {