The commit 6ded286555c2 ("sh_eth: Fix RX recovery on R-Car in case of RX ring underrun") added a check for an bad RDFAR offset in sh_eth_rx(), so that the code could work on the R-Car Ether controllers which don't have this register (and TDFAR), then the commit 3365711df02 ("sh_eth: WARN on access to a register not implemented in a particular chip") replaced offset 0 with 0xffff. Adding/checking the 'no_xdfar' bit field in the 'struct sh_eth_cpu_data' instead results in less object code... Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx> --- drivers/net/ethernet/renesas/sh_eth.c | 5 +++-- drivers/net/ethernet/renesas/sh_eth.h | 1 + 2 files changed, 4 insertions(+), 2 deletions(-) Index: net-next/drivers/net/ethernet/renesas/sh_eth.c =================================================================== --- net-next.orig/drivers/net/ethernet/renesas/sh_eth.c +++ net-next/drivers/net/ethernet/renesas/sh_eth.c @@ -702,6 +702,7 @@ static struct sh_eth_cpu_data rcar_gen1_ .mpr = 1, .tpauser = 1, .hw_swap = 1, + .no_xdfar = 1, }; /* R-Car Gen2 and RZ/G1 */ @@ -735,6 +736,7 @@ static struct sh_eth_cpu_data rcar_gen2_ .mpr = 1, .tpauser = 1, .hw_swap = 1, + .no_xdfar = 1, .rmiimode = 1, .magic = 1, }; @@ -1615,8 +1617,7 @@ static int sh_eth_rx(struct net_device * /* If we don't need to check status, don't. -KDU */ if (!(sh_eth_read(ndev, EDRRR) & EDRRR_R)) { /* fix the values for the next receiving if RDE is set */ - if (intr_status & EESR_RDE && - mdp->reg_offset[RDFAR] != SH_ETH_OFFSET_INVALID) { + if (intr_status & EESR_RDE && !mdp->cd->no_xdfar) { u32 count = (sh_eth_read(ndev, RDFAR) - sh_eth_read(ndev, RDLAR)) >> 4; Index: net-next/drivers/net/ethernet/renesas/sh_eth.h =================================================================== --- net-next.orig/drivers/net/ethernet/renesas/sh_eth.h +++ net-next/drivers/net/ethernet/renesas/sh_eth.h @@ -508,6 +508,7 @@ struct sh_eth_cpu_data { unsigned rpadir:1; /* E-DMAC have RPADIR */ unsigned no_trimd:1; /* E-DMAC DO NOT have TRIMD */ unsigned no_ade:1; /* E-DMAC DO NOT have ADE bit in EESR */ + unsigned no_xdfar:1; /* E-DMAC DOES NOT have RDFAR/TDFAR */ unsigned xdfar_rw:1; /* E-DMAC has writeable RDFAR/TDFAR */ unsigned hw_checksum:1; /* E-DMAC has CSMR */ unsigned select_mii:1; /* EtherC have RMII_MII (MII select register) */