dm9000: add checksum offload support

Add checksum offload support for DM9000A and DM9000B chips.

v2 changes: added a local copy of ip_summed to save IO cycles in dm9000_send_packet
v3 changes: trans_start updating is removed.

Signed-off-by: Yeasah Pell <yeasah@comrex.com>
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/dm9000.c b/drivers/net/dm9000.c
index ffd9edc..8603806 100644 (file)
--- a/drivers/net/dm9000.c
+++ b/drivers/net/dm9000.c
@@ -92,6 +92,7 @@ typedef struct board_info {
        u16             tx_pkt_cnt;
        u16             queue_pkt_len;
        u16             queue_start_addr;
+       u16             queue_ip_summed;
        u16             dbug_cnt;
        u8              io_mode;                /* 0:word, 2:byte */
        u8              phy_addr;
@@ -124,6 +125,10 @@ typedef struct board_info {
 
        struct mii_if_info mii;
        u32             msg_enable;
+
+       int             rx_csum;
+       int             can_csum;
+       int             ip_summed;
 } board_info_t;
 
 /* debug code */
@@ -460,6 +465,40 @@ static int dm9000_nway_reset(struct net_device *dev)
        return mii_nway_restart(&dm->mii);
 }
 
+static uint32_t dm9000_get_rx_csum(struct net_device *dev)
+{
+       board_info_t *dm = to_dm9000_board(dev);
+       return dm->rx_csum;
+}
+
+static int dm9000_set_rx_csum(struct net_device *dev, uint32_t data)
+{
+       board_info_t *dm = to_dm9000_board(dev);
+       unsigned long flags;
+
+       if (dm->can_csum) {
+               dm->rx_csum = data;
+
+               spin_lock_irqsave(&dm->lock, flags);
+               iow(dm, DM9000_RCSR, dm->rx_csum ? RCSR_CSUM : 0);
+               spin_unlock_irqrestore(&dm->lock, flags);
+
+               return 0;
+       }
+
+       return -EOPNOTSUPP;
+}
+
+static int dm9000_set_tx_csum(struct net_device *dev, uint32_t data)
+{
+       board_info_t *dm = to_dm9000_board(dev);
+       int ret = -EOPNOTSUPP;
+
+       if (dm->can_csum)
+               ret = ethtool_op_set_tx_csum(dev, data);
+       return ret;
+}
+
 static u32 dm9000_get_link(struct net_device *dev)
 {
        board_info_t *dm = to_dm9000_board(dev);
@@ -540,6 +579,10 @@ static const struct ethtool_ops dm9000_ethtool_ops = {
        .get_eeprom_len         = dm9000_get_eeprom_len,
        .get_eeprom             = dm9000_get_eeprom,
        .set_eeprom             = dm9000_set_eeprom,
+       .get_rx_csum            = dm9000_get_rx_csum,
+       .set_rx_csum            = dm9000_set_rx_csum,
+       .get_tx_csum            = ethtool_op_get_tx_csum,
+       .set_tx_csum            = dm9000_set_tx_csum,
 };
 
 static void dm9000_show_carrier(board_info_t *db,
@@ -685,6 +728,9 @@ dm9000_init_dm9000(struct net_device *dev)
        /* I/O mode */
        db->io_mode = ior(db, DM9000_ISR) >> 6; /* ISR bit7:6 keeps I/O mode */
 
+       /* Checksum mode */
+       dm9000_set_rx_csum(dev, db->rx_csum);
+
        /* GPIO0 on pre-activate PHY */
        iow(db, DM9000_GPR, 0); /* REG_1F bit0 activate phyxcer */
        iow(db, DM9000_GPCR, GPCR_GEP_CNTL);    /* Let GPIO0 output */
@@ -743,6 +789,29 @@ static void dm9000_timeout(struct net_device *dev)
        spin_unlock_irqrestore(&db->lock, flags);
 }
 
+static void dm9000_send_packet(struct net_device *dev,
+                              int ip_summed,
+                              u16 pkt_len)
+{
+       board_info_t *dm = to_dm9000_board(dev);
+
+       /* The DM9000 is not smart enough to leave fragmented packets alone. */
+       if (dm->ip_summed != ip_summed) {
+               if (ip_summed == CHECKSUM_NONE)
+                       iow(dm, DM9000_TCCR, 0);
+               else
+                       iow(dm, DM9000_TCCR, TCCR_IP | TCCR_UDP | TCCR_TCP);
+               dm->ip_summed = ip_summed;
+       }
+
+       /* Set TX length to DM9000 */
+       iow(dm, DM9000_TXPLL, pkt_len);
+       iow(dm, DM9000_TXPLH, pkt_len >> 8);
+
+       /* Issue TX polling command */
+       iow(dm, DM9000_TCR, TCR_TXREQ); /* Cleared after TX complete */
+}
+
 /*
  *  Hardware start transmission.
  *  Send a packet to media from the upper layer.
@@ -769,17 +838,11 @@ dm9000_start_xmit(struct sk_buff *skb, struct net_device *dev)
        db->tx_pkt_cnt++;
        /* TX control: First packet immediately send, second packet queue */
        if (db->tx_pkt_cnt == 1) {
-               /* Set TX length to DM9000 */
-               iow(db, DM9000_TXPLL, skb->len);
-               iow(db, DM9000_TXPLH, skb->len >> 8);
-
-               /* Issue TX polling command */
-               iow(db, DM9000_TCR, TCR_TXREQ); /* Cleared after TX complete */
-
-               dev->trans_start = jiffies;     /* save the time stamp */
+               dm9000_send_packet(dev, skb->ip_summed, skb->len);
        } else {
                /* Second packet */
                db->queue_pkt_len = skb->len;
+               db->queue_ip_summed = skb->ip_summed;
                netif_stop_queue(dev);
        }
 
@@ -809,12 +872,9 @@ static void dm9000_tx_done(struct net_device *dev, board_info_t *db)
                        dev_dbg(db->dev, "tx done, NSR %02x\n", tx_status);
 
                /* Queue packet check & send */
-               if (db->tx_pkt_cnt > 0) {
-                       iow(db, DM9000_TXPLL, db->queue_pkt_len);
-                       iow(db, DM9000_TXPLH, db->queue_pkt_len >> 8);
-                       iow(db, DM9000_TCR, TCR_TXREQ);
-                       dev->trans_start = jiffies;
-               }
+               if (db->tx_pkt_cnt > 0)
+                       dm9000_send_packet(dev, db->queue_ip_summed,
+                                          db->queue_pkt_len);
                netif_wake_queue(dev);
        }
 }
@@ -846,14 +906,14 @@ dm9000_rx(struct net_device *dev)
                rxbyte = readb(db->io_data);
 
                /* Status check: this byte must be 0 or 1 */
-               if (rxbyte > DM9000_PKT_RDY) {
+               if (rxbyte & DM9000_PKT_ERR) {
                        dev_warn(db->dev, "status check fail: %d\n", rxbyte);
                        iow(db, DM9000_RCR, 0x00);      /* Stop Device */
                        iow(db, DM9000_ISR, IMR_PAR);   /* Stop INT request */
                        return;
                }
 
-               if (rxbyte != DM9000_PKT_RDY)
+               if (!(rxbyte & DM9000_PKT_RDY))
                        return;
 
                /* A packet ready now  & Get status/length */
@@ -914,6 +974,12 @@ dm9000_rx(struct net_device *dev)
 
                        /* Pass to upper layer */
                        skb->protocol = eth_type_trans(skb, dev);
+                       if (db->rx_csum) {
+                               if ((((rxbyte & 0x1c) << 3) & rxbyte) == 0)
+                                       skb->ip_summed = CHECKSUM_UNNECESSARY;
+                               else
+                                       skb->ip_summed = CHECKSUM_NONE;
+                       }
                        netif_rx(skb);
                        dev->stats.rx_packets++;
 
@@ -922,7 +988,7 @@ dm9000_rx(struct net_device *dev)
 
                        (db->dumpblk)(db->io_data, RxLen);
                }
-       } while (rxbyte == DM9000_PKT_RDY);
+       } while (rxbyte & DM9000_PKT_RDY);
 }
 
 static irqreturn_t dm9000_interrupt(int irq, void *dev_id)
@@ -1349,6 +1415,13 @@ dm9000_probe(struct platform_device *pdev)
                db->type = TYPE_DM9000E;
        }
 
+       /* dm9000a/b are capable of hardware checksum offload */
+       if (db->type == TYPE_DM9000A || db->type == TYPE_DM9000B) {
+               db->can_csum = 1;
+               db->rx_csum = 1;
+               ndev->features |= NETIF_F_IP_CSUM;
+       }
+
        /* from this point we assume that we have found a DM9000 */
 
        /* driver system function */

diff --git a/drivers/net/dm9000.h b/drivers/net/dm9000.h
index ba25cf5..80817c2 100644 (file)
--- a/drivers/net/dm9000.h
+++ b/drivers/net/dm9000.h
@@ -45,6 +45,10 @@
 #define DM9000_CHIPR           0x2C
 #define DM9000_SMCR            0x2F
 
+#define DM9000_ETXCSR          0x30
+#define DM9000_TCCR           0x31
+#define DM9000_RCSR           0x32
+
 #define CHIPR_DM9000A         0x19
 #define CHIPR_DM9000B         0x1B
 
@@ -131,7 +135,21 @@
 
 #define GPCR_GEP_CNTL       (1<<0)
 
+#define TCCR_IP                    (1<<0)
+#define TCCR_TCP           (1<<1)
+#define TCCR_UDP           (1<<2)
+
+#define RCSR_UDP_BAD       (1<<7)
+#define RCSR_TCP_BAD       (1<<6)
+#define RCSR_IP_BAD        (1<<5)
+#define RCSR_UDP           (1<<4)
+#define RCSR_TCP           (1<<3)
+#define RCSR_IP                    (1<<2)
+#define RCSR_CSUM          (1<<1)
+#define RCSR_DISCARD       (1<<0)
+
 #define DM9000_PKT_RDY         0x01    /* Packet ready to receive */
+#define DM9000_PKT_ERR         0x02
 #define DM9000_PKT_MAX         1536    /* Received packet max size */
 
 /* DM9000A / DM9000B definitions */