net: axienet: Handle jumbo frames for lesser frame sizes

In the current implementation, jumbo frames are supported only
for the frame sizes > 16K. This patch corrects this logic to
handle jumbo frames for lesser frame sizes (< 16K) ensuring jumbo frame
MTU is within the limit of max frame size configured in the h/w
design.

Signed-off-by: Srikanth Thokala <sthokal@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 23 insertions, 23 deletions

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index b83425393a24..b1081e1893b0 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -471,14 +471,16 @@ static void axienet_device_reset(struct net_device *ndev)
         __axienet_device_reset(lp, &ndev->dev, XAXIDMA_RX_CR_OFFSET);
 
         lp->max_frm_size = XAE_MAX_VLAN_FRAME_SIZE;
+        lp->options |= XAE_OPTION_VLAN;
         lp->options &= (~XAE_OPTION_JUMBO);
 
         if ((ndev->mtu > XAE_MTU) &&
-            (ndev->mtu <= XAE_JUMBO_MTU) &&
-            (lp->jumbo_support)) {
-                lp->max_frm_size = ndev->mtu + XAE_HDR_VLAN_SIZE +
-                                   XAE_TRL_SIZE;
-                lp->options |= XAE_OPTION_JUMBO;
+                (ndev->mtu <= XAE_JUMBO_MTU)) {
+                lp->max_frm_size = ndev->mtu + VLAN_ETH_HLEN +
+                                        XAE_TRL_SIZE;
+
+                if (lp->max_frm_size <= lp->rxmem)
+                        lp->options |= XAE_OPTION_JUMBO;
         }
 
         if (axienet_dma_bd_init(ndev)) {
@@ -1027,15 +1029,15 @@ static int axienet_change_mtu(struct net_device *ndev, int new_mtu)
 
         if (netif_running(ndev))
                 return -EBUSY;
-        if (lp->jumbo_support) {
-                if ((new_mtu > XAE_JUMBO_MTU) || (new_mtu < 64))
-                        return -EINVAL;
-                ndev->mtu = new_mtu;
-        } else {
-                if ((new_mtu > XAE_MTU) || (new_mtu < 64))
-                        return -EINVAL;
-                ndev->mtu = new_mtu;
-        }
+
+        if ((new_mtu + VLAN_ETH_HLEN +
+                XAE_TRL_SIZE) > lp->rxmem)
+                return -EINVAL;
+
+        if ((new_mtu > XAE_JUMBO_MTU) || (new_mtu < 64))
+                return -EINVAL;
+
+        ndev->mtu = new_mtu;
 
         return 0;
 }
@@ -1556,16 +1558,14 @@ static int axienet_of_probe(struct platform_device *op)
                 }
         }
         /* For supporting jumbo frames, the Axi Ethernet hardware must have
-         * a larger Rx/Tx Memory. Typically, the size must be more than or
-         * equal to 16384 bytes, so that we can enable jumbo option and start
-         * supporting jumbo frames. Here we check for memory allocated for
-         * Rx/Tx in the hardware from the device-tree and accordingly set
-         * flags. */
+         * a larger Rx/Tx Memory. Typically, the size must be large so that
+         * we can enable jumbo option and start supporting jumbo frames.
+         * Here we check for memory allocated for Rx/Tx in the hardware from
+         * the device-tree and accordingly set flags.
+         */
         p = (__be32 *) of_get_property(op->dev.of_node, "xlnx,rxmem", NULL);
-        if (p) {
-                if ((be32_to_cpup(p)) >= 0x4000)
-                        lp->jumbo_support = 1;
-        }
+        if (p)
+                lp->rxmem = be32_to_cpup(p);
         p = (__be32 *) of_get_property(op->dev.of_node, "xlnx,phy-type", NULL);
         if (p)
                 lp->phy_type = be32_to_cpup(p);