[PATCH 04/12] net: axienet: Handle jumbo frames for lesser frame sizes

Michal Simek
2015-05-05T09:30:00Z

From: Srikanth Thokala <srikanth.thokala@xilinx.com>

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>
---

drivers/net/ethernet/xilinx/xilinx_axienet.h | 9 ++---
drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 46 +++++++++++------------
2 files changed, 27 insertions(+), 28 deletions(-)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet.h b/drivers/net/ethernet/xilinx/xilinx_axienet.h
index 4c9b4fa1d3c1..4e309440964a 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet.h
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet.h
@@ -11,16 +11,16 @@
#include <linux/netdevice.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
+#include <linux/if_vlan.h>

/* Packet size info */
#define XAE_HDR_SIZE 14 /* Size of Ethernet header */
-#define XAE_HDR_VLAN_SIZE 18 /* Size of an Ethernet hdr + VLAN */
#define XAE_TRL_SIZE 4 /* Size of Ethernet trailer (FCS) */
#define XAE_MTU 1500 /* Max MTU of an Ethernet frame */
#define XAE_JUMBO_MTU 9000 /* Max MTU of a jumbo Eth. frame */

#define XAE_MAX_FRAME_SIZE (XAE_MTU + XAE_HDR_SIZE + XAE_TRL_SIZE)
-#define XAE_MAX_VLAN_FRAME_SIZE (XAE_MTU + XAE_HDR_VLAN_SIZE + XAE_TRL_SIZE)
+#define XAE_MAX_VLAN_FRAME_SIZE (XAE_MTU + VLAN_ETH_HLEN + XAE_TRL_SIZE)
#define XAE_MAX_JUMBO_FRAME_SIZE (XAE_JUMBO_MTU + XAE_HDR_SIZE + XAE_TRL_SIZE)

/* Configuration options */
@@ -407,8 +407,7 @@ struct axidma_bd {
* Txed/Rxed in the existing hardware. If jumbo option is
* supported, the maximum frame size would be 9k. Else it is
* 1522 bytes (assuming support for basic VLAN)
- * @jumbo_support: Stores hardware configuration for jumbo support. If hardware
- * can handle jumbo packets, this entry will be 1, else 0.
+ * @rxmem: Stores rx memory size for jumbo frame handling.
*/
struct axienet_local {
struct net_device *ndev;
@@ -446,7 +445,7 @@ struct axienet_local {
u32 rx_bd_ci;

u32 max_frm_size;
- u32 jumbo_support;
+ u32 rxmem;

int csum_offload_on_tx_path;
int csum_offload_on_rx_path;
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);
--
2.3.5