stmmac: allow mtu bigger than 1500 in case of normal desc (V4)

This patch allows to set the mtu bigger than 1500
in case of normal descriptors.
This is helping some SPEAr customers.

Signed-off-by: Deepak SIKRI <deepak.sikri@st.com>
Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 9 insertions, 3 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
index 029c2a2cf524..e13226b80d47 100644
--- a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
@@ -126,6 +126,7 @@ static void ndesc_init_rx_desc(struct dma_desc *p, unsigned int ring_size,
         for (i = 0; i < ring_size; i++) {
                 p->des01.rx.own = 1;
                 p->des01.rx.buffer1_size = BUF_SIZE_2KiB - 1;
+                p->des01.rx.buffer2_size = BUF_SIZE_2KiB - 1;
                 if (i == ring_size - 1)
                         p->des01.rx.end_ring = 1;
                 if (disable_rx_ic)
@@ -183,7 +184,12 @@ static void ndesc_prepare_tx_desc(struct dma_desc *p, int is_fs, int len,
                                   int csum_flag)
 {
         p->des01.tx.first_segment = is_fs;
-        p->des01.tx.buffer1_size = len;
+
+        if (unlikely(len > BUF_SIZE_2KiB)) {
+                p->des01.etx.buffer1_size = BUF_SIZE_2KiB - 1;
+                p->des01.etx.buffer2_size = len - p->des01.etx.buffer1_size;
+        } else
+                p->des01.tx.buffer1_size = len;
 }
 
 static void ndesc_clear_tx_ic(struct dma_desc *p)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index f80190d78f90..3c7ef7127d75 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1412,10 +1412,10 @@ static int stmmac_change_mtu(struct net_device *dev, int new_mtu)
                 return -EBUSY;
         }
 
-        if (priv->plat->has_gmac)
+        if (priv->plat->enh_desc)
                 max_mtu = JUMBO_LEN;
         else
-                max_mtu = ETH_DATA_LEN;
+                max_mtu = BUF_SIZE_4KiB;
 
         if ((new_mtu < 46) || (new_mtu > max_mtu)) {
                 pr_err("%s: invalid MTU, max MTU is: %d\n", dev->name, max_mtu);