From c8aaea25e0b069e9572caa74f984e109899c1765 Mon Sep 17 00:00:00 2001 From: Dale Farnsworth Date: Fri, 3 Mar 2006 10:02:05 -0700 Subject: [PATCH] mv643xx_eth: Refactor tx command queuing code Simplify and remove redundant code for filling transmit descriptors. No changes in features; it's just a code reorganization/cleanup. Signed-off-by: Dale Farnsworth Signed-off-by: Jeff Garzik --- drivers/net/mv643xx_eth.c | 549 +++++++++++++--------------------------------- 1 file changed, 152 insertions(+), 397 deletions(-) (limited to 'drivers/net/mv643xx_eth.c') diff --git a/drivers/net/mv643xx_eth.c b/drivers/net/mv643xx_eth.c index 098f3a28837c..260be8048d3c 100644 --- a/drivers/net/mv643xx_eth.c +++ b/drivers/net/mv643xx_eth.c @@ -10,7 +10,7 @@ * * Copyright (C) 2003 Ralf Baechle * - * Copyright (C) 2004-2005 MontaVista Software, Inc. + * Copyright (C) 2004-2006 MontaVista Software, Inc. * Dale Farnsworth * * Copyright (C) 2004 Steven J. Hill @@ -554,7 +554,7 @@ static irqreturn_t mv643xx_eth_int_handler(int irq, void *dev_id, /* UDP change : We may need this */ if ((eth_int_cause_ext & 0x0000ffff) && (mv643xx_eth_free_tx_queue(dev, eth_int_cause_ext) == 0) && - (mp->tx_ring_size > mp->tx_desc_count + MAX_DESCS_PER_SKB)) + (mp->tx_ring_size - mp->tx_desc_count > MAX_DESCS_PER_SKB)) netif_wake_queue(dev); #ifdef MV643XX_NAPI } else { @@ -598,7 +598,7 @@ static irqreturn_t mv643xx_eth_int_handler(int irq, void *dev_id, mv643xx_eth_update_pscr(dev, &cmd); if (!netif_carrier_ok(dev)) { netif_carrier_on(dev); - if (mp->tx_ring_size > mp->tx_desc_count + + if (mp->tx_ring_size - mp->tx_desc_count > MAX_DESCS_PER_SKB) { netif_wake_queue(dev); /* Start TX queue */ @@ -777,9 +777,6 @@ static void ether_init_tx_desc_ring(struct mv643xx_private *mp) mp->tx_curr_desc_q = 0; mp->tx_used_desc_q = 0; -#ifdef MV643XX_CHECKSUM_OFFLOAD_TX - mp->tx_first_desc_q = 0; -#endif mp->tx_desc_area_size = tx_desc_num * sizeof(struct eth_tx_desc); @@ -1085,8 +1082,7 @@ static void mv643xx_tx(struct net_device *dev) } if (netif_queue_stopped(dev) && - mp->tx_ring_size > - mp->tx_desc_count + MAX_DESCS_PER_SKB) + mp->tx_ring_size - mp->tx_desc_count > MAX_DESCS_PER_SKB) netif_wake_queue(dev); } @@ -1133,7 +1129,10 @@ static int mv643xx_poll(struct net_device *dev, int *budget) } #endif -/* Hardware can't handle unaligned fragments smaller than 9 bytes. +/** + * has_tiny_unaligned_frags - check if skb has any small, unaligned fragments + * + * Hardware can't handle unaligned fragments smaller than 9 bytes. * This helper function detects that case. */ @@ -1150,223 +1149,170 @@ static inline unsigned int has_tiny_unaligned_frags(struct sk_buff *skb) return 0; } +/** + * eth_alloc_tx_desc_index - return the index of the next available tx desc + */ +static int eth_alloc_tx_desc_index(struct mv643xx_private *mp) +{ + int tx_desc_curr; + + tx_desc_curr = mp->tx_curr_desc_q; -/* - * mv643xx_eth_start_xmit - * - * This function is queues a packet in the Tx descriptor for - * required port. - * - * Input : skb - a pointer to socket buffer - * dev - a pointer to the required port + BUG_ON(mp->tx_desc_count >= mp->tx_ring_size); + mp->tx_desc_count++; + + mp->tx_curr_desc_q = (tx_desc_curr + 1) % mp->tx_ring_size; + + BUG_ON(mp->tx_curr_desc_q == mp->tx_used_desc_q); + + return tx_desc_curr; +} + +/** + * eth_tx_fill_frag_descs - fill tx hw descriptors for an skb's fragments. * - * Output : zero upon success + * Ensure the data for each fragment to be transmitted is mapped properly, + * then fill in descriptors in the tx hw queue. */ -static int mv643xx_eth_start_xmit(struct sk_buff *skb, struct net_device *dev) +static void eth_tx_fill_frag_descs(struct mv643xx_private *mp, + struct sk_buff *skb) { - struct mv643xx_private *mp = netdev_priv(dev); + int frag; + int tx_index; + struct eth_tx_desc *desc; struct net_device_stats *stats = &mp->stats; - ETH_FUNC_RET_STATUS status; - unsigned long flags; - struct pkt_info pkt_info; - if (netif_queue_stopped(dev)) { - printk(KERN_ERR - "%s: Tried sending packet when interface is stopped\n", - dev->name); - return 1; + for (frag = 0; frag < skb_shinfo(skb)->nr_frags; frag++) { + skb_frag_t *this_frag = &skb_shinfo(skb)->frags[frag]; + + tx_index = eth_alloc_tx_desc_index(mp); + desc = &mp->p_tx_desc_area[tx_index]; + + desc->cmd_sts = ETH_BUFFER_OWNED_BY_DMA; + /* Last Frag enables interrupt and frees the skb */ + if (frag == (skb_shinfo(skb)->nr_frags - 1)) { + desc->cmd_sts |= ETH_ZERO_PADDING | + ETH_TX_LAST_DESC | + ETH_TX_ENABLE_INTERRUPT; + mp->tx_skb[tx_index] = skb; + } else + mp->tx_skb[tx_index] = 0; + + desc = &mp->p_tx_desc_area[tx_index]; + desc->l4i_chk = 0; + desc->byte_cnt = this_frag->size; + desc->buf_ptr = dma_map_page(NULL, this_frag->page, + this_frag->page_offset, + this_frag->size, + DMA_TO_DEVICE); + stats->tx_bytes += this_frag->size; } +} - /* This is a hard error, log it. */ - if ((mp->tx_ring_size - mp->tx_desc_count) <= - (skb_shinfo(skb)->nr_frags + 1)) { - netif_stop_queue(dev); - printk(KERN_ERR - "%s: Bug in mv643xx_eth - Trying to transmit when" - " queue full !\n", dev->name); - return 1; - } +/** + * eth_tx_submit_descs_for_skb - submit data from an skb to the tx hw + * + * Ensure the data for an skb to be transmitted is mapped properly, + * then fill in descriptors in the tx hw queue and start the hardware. + */ +static int eth_tx_submit_descs_for_skb(struct mv643xx_private *mp, + struct sk_buff *skb) +{ + int tx_index; + struct eth_tx_desc *desc; + u32 cmd_sts; + int length; + int tx_bytes = 0; - /* Paranoid check - this shouldn't happen */ - if (skb == NULL) { - stats->tx_dropped++; - printk(KERN_ERR "mv64320_eth paranoid check failed\n"); - return 1; - } + cmd_sts = ETH_TX_FIRST_DESC | ETH_GEN_CRC | ETH_BUFFER_OWNED_BY_DMA; -#ifdef MV643XX_CHECKSUM_OFFLOAD_TX - if (has_tiny_unaligned_frags(skb)) { - if ((skb_linearize(skb, GFP_ATOMIC) != 0)) { - stats->tx_dropped++; - printk(KERN_DEBUG "%s: failed to linearize tiny " - "unaligned fragment\n", dev->name); - return 1; - } + tx_index = eth_alloc_tx_desc_index(mp); + desc = &mp->p_tx_desc_area[tx_index]; + + if (skb_shinfo(skb)->nr_frags) { + eth_tx_fill_frag_descs(mp, skb); + + length = skb_headlen(skb); + mp->tx_skb[tx_index] = 0; + } else { + cmd_sts |= ETH_ZERO_PADDING | + ETH_TX_LAST_DESC | + ETH_TX_ENABLE_INTERRUPT; + length = skb->len; + mp->tx_skb[tx_index] = skb; } - spin_lock_irqsave(&mp->lock, flags); + desc->byte_cnt = length; + desc->buf_ptr = dma_map_single(NULL, skb->data, length, DMA_TO_DEVICE); + tx_bytes += length; - if (!skb_shinfo(skb)->nr_frags) { - if (skb->ip_summed != CHECKSUM_HW) { - /* Errata BTS #50, IHL must be 5 if no HW checksum */ - pkt_info.cmd_sts = ETH_TX_ENABLE_INTERRUPT | - ETH_TX_FIRST_DESC | - ETH_TX_LAST_DESC | - 5 << ETH_TX_IHL_SHIFT; - pkt_info.l4i_chk = 0; - } else { - pkt_info.cmd_sts = ETH_TX_ENABLE_INTERRUPT | - ETH_TX_FIRST_DESC | - ETH_TX_LAST_DESC | - ETH_GEN_TCP_UDP_CHECKSUM | - ETH_GEN_IP_V_4_CHECKSUM | - skb->nh.iph->ihl << ETH_TX_IHL_SHIFT; - /* CPU already calculated pseudo header checksum. */ - if ((skb->protocol == ETH_P_IP) && - (skb->nh.iph->protocol == IPPROTO_UDP) ) { - pkt_info.cmd_sts |= ETH_UDP_FRAME; - pkt_info.l4i_chk = skb->h.uh->check; - } else if ((skb->protocol == ETH_P_IP) && - (skb->nh.iph->protocol == IPPROTO_TCP)) - pkt_info.l4i_chk = skb->h.th->check; - else { - printk(KERN_ERR - "%s: chksum proto != IPv4 TCP or UDP\n", - dev->name); - spin_unlock_irqrestore(&mp->lock, flags); - return 1; - } + if (skb->ip_summed == CHECKSUM_HW) { + BUG_ON(skb->protocol != ETH_P_IP); + + cmd_sts |= ETH_GEN_TCP_UDP_CHECKSUM | + ETH_GEN_IP_V_4_CHECKSUM | + skb->nh.iph->ihl << ETH_TX_IHL_SHIFT; + + switch (skb->nh.iph->protocol) { + case IPPROTO_UDP: + cmd_sts |= ETH_UDP_FRAME; + desc->l4i_chk = skb->h.uh->check; + break; + case IPPROTO_TCP: + desc->l4i_chk = skb->h.th->check; + break; + default: + BUG(); } - pkt_info.byte_cnt = skb->len; - pkt_info.buf_ptr = dma_map_single(NULL, skb->data, skb->len, - DMA_TO_DEVICE); - pkt_info.return_info = skb; - status = eth_port_send(mp, &pkt_info); - if ((status == ETH_ERROR) || (status == ETH_QUEUE_FULL)) - printk(KERN_ERR "%s: Error on transmitting packet\n", - dev->name); - stats->tx_bytes += pkt_info.byte_cnt; } else { - unsigned int frag; - - /* first frag which is skb header */ - pkt_info.byte_cnt = skb_headlen(skb); - pkt_info.buf_ptr = dma_map_single(NULL, skb->data, - skb_headlen(skb), - DMA_TO_DEVICE); - pkt_info.l4i_chk = 0; - pkt_info.return_info = 0; - - if (skb->ip_summed != CHECKSUM_HW) - /* Errata BTS #50, IHL must be 5 if no HW checksum */ - pkt_info.cmd_sts = ETH_TX_FIRST_DESC | - 5 << ETH_TX_IHL_SHIFT; - else { - pkt_info.cmd_sts = ETH_TX_FIRST_DESC | - ETH_GEN_TCP_UDP_CHECKSUM | - ETH_GEN_IP_V_4_CHECKSUM | - skb->nh.iph->ihl << ETH_TX_IHL_SHIFT; - /* CPU already calculated pseudo header checksum. */ - if ((skb->protocol == ETH_P_IP) && - (skb->nh.iph->protocol == IPPROTO_UDP)) { - pkt_info.cmd_sts |= ETH_UDP_FRAME; - pkt_info.l4i_chk = skb->h.uh->check; - } else if ((skb->protocol == ETH_P_IP) && - (skb->nh.iph->protocol == IPPROTO_TCP)) - pkt_info.l4i_chk = skb->h.th->check; - else { - printk(KERN_ERR - "%s: chksum proto != IPv4 TCP or UDP\n", - dev->name); - spin_unlock_irqrestore(&mp->lock, flags); - return 1; - } - } + /* Errata BTS #50, IHL must be 5 if no HW checksum */ + cmd_sts |= 5 << ETH_TX_IHL_SHIFT; + desc->l4i_chk = 0; + } - status = eth_port_send(mp, &pkt_info); - if (status != ETH_OK) { - if ((status == ETH_ERROR)) - printk(KERN_ERR - "%s: Error on transmitting packet\n", - dev->name); - if (status == ETH_QUEUE_FULL) - printk("Error on Queue Full \n"); - if (status == ETH_QUEUE_LAST_RESOURCE) - printk("Tx resource error \n"); - } - stats->tx_bytes += pkt_info.byte_cnt; - - /* Check for the remaining frags */ - for (frag = 0; frag < skb_shinfo(skb)->nr_frags; frag++) { - skb_frag_t *this_frag = &skb_shinfo(skb)->frags[frag]; - pkt_info.l4i_chk = 0x0000; - pkt_info.cmd_sts = 0x00000000; - - /* Last Frag enables interrupt and frees the skb */ - if (frag == (skb_shinfo(skb)->nr_frags - 1)) { - pkt_info.cmd_sts |= ETH_TX_ENABLE_INTERRUPT | - ETH_TX_LAST_DESC; - pkt_info.return_info = skb; - } else { - pkt_info.return_info = 0; - } - pkt_info.l4i_chk = 0; - pkt_info.byte_cnt = this_frag->size; + /* ensure all other descriptors are written before first cmd_sts */ + wmb(); + desc->cmd_sts = cmd_sts; - pkt_info.buf_ptr = dma_map_page(NULL, this_frag->page, - this_frag->page_offset, - this_frag->size, - DMA_TO_DEVICE); + /* ensure all descriptors are written before poking hardware */ + wmb(); + mv643xx_eth_port_enable_tx(mp->port_num, mp->port_tx_queue_command); - status = eth_port_send(mp, &pkt_info); + return tx_bytes; +} - if (status != ETH_OK) { - if ((status == ETH_ERROR)) - printk(KERN_ERR "%s: Error on " - "transmitting packet\n", - dev->name); +/** + * mv643xx_eth_start_xmit - queue an skb to the hardware for transmission + * + */ +static int mv643xx_eth_start_xmit(struct sk_buff *skb, struct net_device *dev) +{ + struct mv643xx_private *mp = netdev_priv(dev); + struct net_device_stats *stats = &mp->stats; + unsigned long flags; - if (status == ETH_QUEUE_LAST_RESOURCE) - printk("Tx resource error \n"); + BUG_ON(netif_queue_stopped(dev)); + BUG_ON(skb == NULL); + BUG_ON(mp->tx_ring_size - mp->tx_desc_count < MAX_DESCS_PER_SKB); - if (status == ETH_QUEUE_FULL) - printk("Queue is full \n"); - } - stats->tx_bytes += pkt_info.byte_cnt; + if (has_tiny_unaligned_frags(skb)) { + if ((skb_linearize(skb, GFP_ATOMIC) != 0)) { + stats->tx_dropped++; + printk(KERN_DEBUG "%s: failed to linearize tiny " + "unaligned fragment\n", dev->name); + return 1; } } -#else - spin_lock_irqsave(&mp->lock, flags); - - pkt_info.cmd_sts = ETH_TX_ENABLE_INTERRUPT | ETH_TX_FIRST_DESC | - ETH_TX_LAST_DESC; - pkt_info.l4i_chk = 0; - pkt_info.byte_cnt = skb->len; - pkt_info.buf_ptr = dma_map_single(NULL, skb->data, skb->len, - DMA_TO_DEVICE); - pkt_info.return_info = skb; - status = eth_port_send(mp, &pkt_info); - if ((status == ETH_ERROR) || (status == ETH_QUEUE_FULL)) - printk(KERN_ERR "%s: Error on transmitting packet\n", - dev->name); - stats->tx_bytes += pkt_info.byte_cnt; -#endif - /* Check if TX queue can handle another skb. If not, then - * signal higher layers to stop requesting TX - */ - if (mp->tx_ring_size <= (mp->tx_desc_count + MAX_DESCS_PER_SKB)) - /* - * Stop getting skb's from upper layers. - * Getting skb's from upper layers will be enabled again after - * packets are released. - */ - netif_stop_queue(dev); + spin_lock_irqsave(&mp->lock, flags); - /* Update statistics and start of transmittion time */ + stats->tx_bytes = eth_tx_submit_descs_for_skb(mp, skb); stats->tx_packets++; dev->trans_start = jiffies; + if (mp->tx_ring_size - mp->tx_desc_count < MAX_DESCS_PER_SKB) + netif_stop_queue(dev); + spin_unlock_irqrestore(&mp->lock, flags); return 0; /* success */ @@ -1812,22 +1758,6 @@ MODULE_DESCRIPTION("Ethernet driver for Marvell MV643XX"); * to the Rx descriptor ring to enable the reuse of this source. * Return Rx resource is done using the eth_rx_return_buff API. * - * Transmit operation: - * The eth_port_send API supports Scatter-Gather which enables to - * send a packet spanned over multiple buffers. This means that - * for each packet info structure given by the user and put into - * the Tx descriptors ring, will be transmitted only if the 'LAST' - * bit will be set in the packet info command status field. This - * API also consider restriction regarding buffer alignments and - * sizes. - * The user must return a Tx resource after ensuring the buffer - * has been transmitted to enable the Tx ring indexes to update. - * - * BOARD LAYOUT - * This device is on-board. No jumper diagram is necessary. - * - * EXTERNAL INTERFACE - * * Prior to calling the initialization routine eth_port_init() the user * must set the following fields under mv643xx_private struct: * port_num User Ethernet port number. @@ -1881,7 +1811,6 @@ static void eth_port_set_filter_table_entry(int table, unsigned char entry); static void eth_port_init(struct mv643xx_private *mp) { mp->rx_resource_err = 0; - mp->tx_resource_err = 0; eth_port_reset(mp->port_num); @@ -2672,166 +2601,6 @@ static void mv643xx_mdio_write(struct net_device *dev, int phy_id, int location, eth_port_write_smi_reg(mp->port_num, location, val); } -/* - * eth_port_send - Send an Ethernet packet - * - * DESCRIPTION: - * This routine send a given packet described by p_pktinfo parameter. It - * supports transmitting of a packet spaned over multiple buffers. The - * routine updates 'curr' and 'first' indexes according to the packet - * segment passed to the routine. In case the packet segment is first, - * the 'first' index is update. In any case, the 'curr' index is updated. - * If the routine get into Tx resource error it assigns 'curr' index as - * 'first'. This way the function can abort Tx process of multiple - * descriptors per packet. - * - * INPUT: - * struct mv643xx_private *mp Ethernet Port Control srtuct. - * struct pkt_info *p_pkt_info User packet buffer. - * - * OUTPUT: - * Tx ring 'curr' and 'first' indexes are updated. - * - * RETURN: - * ETH_QUEUE_FULL in case of Tx resource error. - * ETH_ERROR in case the routine can not access Tx desc ring. - * ETH_QUEUE_LAST_RESOURCE if the routine uses the last Tx resource. - * ETH_OK otherwise. - * - */ -#ifdef MV643XX_CHECKSUM_OFFLOAD_TX -/* - * Modified to include the first descriptor pointer in case of SG - */ -static ETH_FUNC_RET_STATUS eth_port_send(struct mv643xx_private *mp, - struct pkt_info *p_pkt_info) -{ - int tx_desc_curr, tx_desc_used, tx_first_desc, tx_next_desc; - struct eth_tx_desc *current_descriptor; - struct eth_tx_desc *first_descriptor; - u32 command; - - /* Do not process Tx ring in case of Tx ring resource error */ - if (mp->tx_resource_err) - return ETH_QUEUE_FULL; - - /* - * The hardware requires that each buffer that is <= 8 bytes - * in length must be aligned on an 8 byte boundary. - */ - if (p_pkt_info->byte_cnt <= 8 && p_pkt_info->buf_ptr & 0x7) { - printk(KERN_ERR - "mv643xx_eth port %d: packet size <= 8 problem\n", - mp->port_num); - return ETH_ERROR; - } - - mp->tx_desc_count++; - BUG_ON(mp->tx_desc_count > mp->tx_ring_size); - - /* Get the Tx Desc ring indexes */ - tx_desc_curr = mp->tx_curr_desc_q; - tx_desc_used = mp->tx_used_desc_q; - - current_descriptor = &mp->p_tx_desc_area[tx_desc_curr]; - - tx_next_desc = (tx_desc_curr + 1) % mp->tx_ring_size; - - current_descriptor->buf_ptr = p_pkt_info->buf_ptr; - current_descriptor->byte_cnt = p_pkt_info->byte_cnt; - current_descriptor->l4i_chk = p_pkt_info->l4i_chk; - mp->tx_skb[tx_desc_curr] = p_pkt_info->return_info; - - command = p_pkt_info->cmd_sts | ETH_ZERO_PADDING | ETH_GEN_CRC | - ETH_BUFFER_OWNED_BY_DMA; - if (command & ETH_TX_FIRST_DESC) { - tx_first_desc = tx_desc_curr; - mp->tx_first_desc_q = tx_first_desc; - first_descriptor = current_descriptor; - mp->tx_first_command = command; - } else { - tx_first_desc = mp->tx_first_desc_q; - first_descriptor = &mp->p_tx_desc_area[tx_first_desc]; - BUG_ON(first_descriptor == NULL); - current_descriptor->cmd_sts = command; - } - - if (command & ETH_TX_LAST_DESC) { - wmb(); - first_descriptor->cmd_sts = mp->tx_first_command; - - wmb(); - mv643xx_eth_port_enable_tx(mp->port_num, mp->port_tx_queue_command); - - /* - * Finish Tx packet. Update first desc in case of Tx resource - * error */ - tx_first_desc = tx_next_desc; - mp->tx_first_desc_q = tx_first_desc; - } - - /* Check for ring index overlap in the Tx desc ring */ - if (tx_next_desc == tx_desc_used) { - mp->tx_resource_err = 1; - mp->tx_curr_desc_q = tx_first_desc; - - return ETH_QUEUE_LAST_RESOURCE; - } - - mp->tx_curr_desc_q = tx_next_desc; - - return ETH_OK; -} -#else -static ETH_FUNC_RET_STATUS eth_port_send(struct mv643xx_private *mp, - struct pkt_info *p_pkt_info) -{ - int tx_desc_curr; - int tx_desc_used; - struct eth_tx_desc *current_descriptor; - unsigned int command_status; - - /* Do not process Tx ring in case of Tx ring resource error */ - if (mp->tx_resource_err) - return ETH_QUEUE_FULL; - - mp->tx_desc_count++; - BUG_ON(mp->tx_desc_count > mp->tx_ring_size); - - /* Get the Tx Desc ring indexes */ - tx_desc_curr = mp->tx_curr_desc_q; - tx_desc_used = mp->tx_used_desc_q; - current_descriptor = &mp->p_tx_desc_area[tx_desc_curr]; - - command_status = p_pkt_info->cmd_sts | ETH_ZERO_PADDING | ETH_GEN_CRC; - current_descriptor->buf_ptr = p_pkt_info->buf_ptr; - current_descriptor->byte_cnt = p_pkt_info->byte_cnt; - mp->tx_skb[tx_desc_curr] = p_pkt_info->return_info; - - /* Set last desc with DMA ownership and interrupt enable. */ - wmb(); - current_descriptor->cmd_sts = command_status | - ETH_BUFFER_OWNED_BY_DMA | ETH_TX_ENABLE_INTERRUPT; - - wmb(); - mv643xx_eth_port_enable_tx(mp->port_num, mp->port_tx_queue_command); - - /* Finish Tx packet. Update first desc in case of Tx resource error */ - tx_desc_curr = (tx_desc_curr + 1) % mp->tx_ring_size; - - /* Update the current descriptor */ - mp->tx_curr_desc_q = tx_desc_curr; - - /* Check for ring index overlap in the Tx desc ring */ - if (tx_desc_curr == tx_desc_used) { - mp->tx_resource_err = 1; - return ETH_QUEUE_LAST_RESOURCE; - } - - return ETH_OK; -} -#endif - /* * eth_tx_return_desc - Free all used Tx descriptors * @@ -2858,7 +2627,6 @@ static ETH_FUNC_RET_STATUS eth_tx_return_desc(struct mv643xx_private *mp, struct pkt_info *p_pkt_info) { int tx_desc_used; - int tx_busy_desc; struct eth_tx_desc *p_tx_desc_used; unsigned int command_status; unsigned long flags; @@ -2866,33 +2634,23 @@ static ETH_FUNC_RET_STATUS eth_tx_return_desc(struct mv643xx_private *mp, spin_lock_irqsave(&mp->lock, flags); -#ifdef MV643XX_CHECKSUM_OFFLOAD_TX - tx_busy_desc = mp->tx_first_desc_q; -#else - tx_busy_desc = mp->tx_curr_desc_q; -#endif + BUG_ON(mp->tx_desc_count < 0); + if (mp->tx_desc_count == 0) { + /* no more tx descs in use */ + err = ETH_ERROR; + goto out; + } /* Get the Tx Desc ring indexes */ tx_desc_used = mp->tx_used_desc_q; p_tx_desc_used = &mp->p_tx_desc_area[tx_desc_used]; - /* Sanity check */ - if (p_tx_desc_used == NULL) { - err = ETH_ERROR; - goto out; - } - - /* Stop release. About to overlap the current available Tx descriptor */ - if (tx_desc_used == tx_busy_desc && !mp->tx_resource_err) { - err = ETH_ERROR; - goto out; - } + BUG_ON(p_tx_desc_used == NULL); command_status = p_tx_desc_used->cmd_sts; - - /* Still transmitting... */ if (command_status & (ETH_BUFFER_OWNED_BY_DMA)) { + /* Still transmitting... */ err = ETH_ERROR; goto out; } @@ -2907,9 +2665,6 @@ static ETH_FUNC_RET_STATUS eth_tx_return_desc(struct mv643xx_private *mp, /* Update the next descriptor to release. */ mp->tx_used_desc_q = (tx_desc_used + 1) % mp->tx_ring_size; - /* Any Tx return cancels the Tx resource error status */ - mp->tx_resource_err = 0; - BUG_ON(mp->tx_desc_count == 0); mp->tx_desc_count--; -- cgit v1.2.3-59-g8ed1b