sh_eth: add sh_eth_cpu_data::no_xdfar flag

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@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 4 insertions, 2 deletions

diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
index 306558ef36b5..2bff03345b72 100644
--- a/drivers/net/ethernet/renesas/sh_eth.c
+++ b/drivers/net/ethernet/renesas/sh_eth.c
@@ -702,6 +702,7 @@ static struct sh_eth_cpu_data rcar_gen1_data = {
         .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_data = {
         .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 *ndev, u32 intr_status, int *quota)
         /* 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;
 
diff --git a/drivers/net/ethernet/renesas/sh_eth.h b/drivers/net/ethernet/renesas/sh_eth.h
index a0416e04306a..a5b792ce2ae7 100644
--- a/drivers/net/ethernet/renesas/sh_eth.h
+++ b/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) */