From d4ed8f8d1fb7d59eb63d2eada9a32c2f8c3795e2 Mon Sep 17 00:00:00 2001 From: Linas Vepstas Date: Wed, 13 Dec 2006 15:06:59 -0600 Subject: [PATCH] Spidernet DMA coalescing The current driver code performs 512 DMA mappings of a bunch of 32-byte ring descriptor structures. This is silly, as they are all in contiguous memory. This patch changes the code to dma_map_coherent() each rx/tx ring as a whole. Signed-off-by: Linas Vepstas Cc: James K Lewis Cc: Arnd Bergmann Signed-off-by: Jeff Garzik --- drivers/net/spider_net.c | 103 ++++++++++++++----------------- drivers/net/spider_net.h | 17 ++--- drivers/net/spider_net_ethtool.c | 4 +- 3 files changed, 54 insertions(+), 70 deletions(-) diff --git a/drivers/net/spider_net.c b/drivers/net/spider_net.c index 8ea2fc1b96cb..8c8381cbce0a 100644 --- a/drivers/net/spider_net.c +++ b/drivers/net/spider_net.c @@ -280,72 +280,67 @@ spider_net_free_chain(struct spider_net_card *card, { struct spider_net_descr *descr; - for (descr = chain->tail; !descr->bus_addr; descr = descr->next) { - pci_unmap_single(card->pdev, descr->bus_addr, - SPIDER_NET_DESCR_SIZE, PCI_DMA_BIDIRECTIONAL); + descr = chain->ring; + do { descr->bus_addr = 0; - } + descr->next_descr_addr = 0; + descr = descr->next; + } while (descr != chain->ring); + + dma_free_coherent(&card->pdev->dev, chain->num_desc, + chain->ring, chain->dma_addr); } /** - * spider_net_init_chain - links descriptor chain + * spider_net_init_chain - alloc and link descriptor chain * @card: card structure * @chain: address of chain - * @start_descr: address of descriptor array - * @no: number of descriptors * - * we manage a circular list that mirrors the hardware structure, + * We manage a circular list that mirrors the hardware structure, * except that the hardware uses bus addresses. * - * returns 0 on success, <0 on failure + * Returns 0 on success, <0 on failure */ static int spider_net_init_chain(struct spider_net_card *card, - struct spider_net_descr_chain *chain, - struct spider_net_descr *start_descr, - int no) + struct spider_net_descr_chain *chain) { int i; struct spider_net_descr *descr; dma_addr_t buf; + size_t alloc_size; - descr = start_descr; - memset(descr, 0, sizeof(*descr) * no); + alloc_size = chain->num_desc * sizeof (struct spider_net_descr); - /* set up the hardware pointers in each descriptor */ - for (i=0; idmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE; + chain->ring = dma_alloc_coherent(&card->pdev->dev, alloc_size, + &chain->dma_addr, GFP_KERNEL); - buf = pci_map_single(card->pdev, descr, - SPIDER_NET_DESCR_SIZE, - PCI_DMA_BIDIRECTIONAL); + if (!chain->ring) + return -ENOMEM; - if (pci_dma_mapping_error(buf)) - goto iommu_error; + descr = chain->ring; + memset(descr, 0, alloc_size); + + /* Set up the hardware pointers in each descriptor */ + buf = chain->dma_addr; + for (i=0; i < chain->num_desc; i++, descr++) { + descr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE; descr->bus_addr = buf; + descr->next_descr_addr = 0; descr->next = descr + 1; descr->prev = descr - 1; + buf += sizeof(struct spider_net_descr); } /* do actual circular list */ - (descr-1)->next = start_descr; - start_descr->prev = descr-1; + (descr-1)->next = chain->ring; + chain->ring->prev = descr-1; spin_lock_init(&chain->lock); - chain->head = start_descr; - chain->tail = start_descr; - + chain->head = chain->ring; + chain->tail = chain->ring; return 0; - -iommu_error: - descr = start_descr; - for (i=0; i < no; i++, descr++) - if (descr->bus_addr) - pci_unmap_single(card->pdev, descr->bus_addr, - SPIDER_NET_DESCR_SIZE, - PCI_DMA_BIDIRECTIONAL); - return -ENOMEM; } /** @@ -707,7 +702,7 @@ spider_net_set_low_watermark(struct spider_net_card *card) } /* If TX queue is short, don't even bother with interrupts */ - if (cnt < card->num_tx_desc/4) + if (cnt < card->tx_chain.num_desc/4) return cnt; /* Set low-watermark 3/4th's of the way into the queue. */ @@ -1652,26 +1647,25 @@ spider_net_open(struct net_device *netdev) { struct spider_net_card *card = netdev_priv(netdev); struct spider_net_descr *descr; - int i, result; + int result; - result = -ENOMEM; - if (spider_net_init_chain(card, &card->tx_chain, card->descr, - card->num_tx_desc)) + result = spider_net_init_chain(card, &card->tx_chain); + if (result) goto alloc_tx_failed; - card->low_watermark = NULL; - /* rx_chain is after tx_chain, so offset is descr + tx_count */ - if (spider_net_init_chain(card, &card->rx_chain, - card->descr + card->num_tx_desc, - card->num_rx_desc)) + result = spider_net_init_chain(card, &card->rx_chain); + if (result) goto alloc_rx_failed; - descr = card->rx_chain.head; - for (i=0; i < card->num_rx_desc; i++, descr++) + /* Make a ring of of bus addresses */ + descr = card->rx_chain.ring; + do { descr->next_descr_addr = descr->next->bus_addr; + descr = descr->next; + } while (descr != card->rx_chain.ring); - /* allocate rx skbs */ + /* Allocate rx skbs */ if (spider_net_alloc_rx_skbs(card)) goto alloc_skbs_failed; @@ -1924,6 +1918,7 @@ spider_net_stop(struct net_device *netdev) /* release chains */ spider_net_release_tx_chain(card, 1); + spider_net_free_rx_chain_contents(card); spider_net_free_rx_chain_contents(card); @@ -2057,8 +2052,8 @@ spider_net_setup_netdev(struct spider_net_card *card) card->options.rx_csum = SPIDER_NET_RX_CSUM_DEFAULT; - card->num_tx_desc = tx_descriptors; - card->num_rx_desc = rx_descriptors; + card->tx_chain.num_desc = tx_descriptors; + card->rx_chain.num_desc = rx_descriptors; spider_net_setup_netdev_ops(netdev); @@ -2107,12 +2102,8 @@ spider_net_alloc_card(void) { struct net_device *netdev; struct spider_net_card *card; - size_t alloc_size; - alloc_size = sizeof (*card) + - sizeof (struct spider_net_descr) * rx_descriptors + - sizeof (struct spider_net_descr) * tx_descriptors; - netdev = alloc_etherdev(alloc_size); + netdev = alloc_etherdev(sizeof(struct spider_net_card)); if (!netdev) return NULL; diff --git a/drivers/net/spider_net.h b/drivers/net/spider_net.h index 3e196df29790..4b76ef9524d1 100644 --- a/drivers/net/spider_net.h +++ b/drivers/net/spider_net.h @@ -378,6 +378,9 @@ struct spider_net_descr_chain { spinlock_t lock; struct spider_net_descr *head; struct spider_net_descr *tail; + struct spider_net_descr *ring; + int num_desc; + dma_addr_t dma_addr; }; /* descriptor data_status bits */ @@ -397,8 +400,6 @@ struct spider_net_descr_chain { * 701b8000 would be correct, but every packets gets that flag */ #define SPIDER_NET_DESTROY_RX_FLAGS 0x700b8000 -#define SPIDER_NET_DESCR_SIZE 32 - /* this will be bigger some time */ struct spider_net_options { int rx_csum; /* for rx: if 0 ip_summed=NONE, @@ -441,25 +442,17 @@ struct spider_net_card { struct spider_net_descr_chain rx_chain; struct spider_net_descr *low_watermark; - struct net_device_stats netdev_stats; - - struct spider_net_options options; - - spinlock_t intmask_lock; struct tasklet_struct rxram_full_tl; struct timer_list tx_timer; - struct work_struct tx_timeout_task; atomic_t tx_timeout_task_counter; wait_queue_head_t waitq; /* for ethtool */ int msg_enable; - int num_rx_desc; - int num_tx_desc; + struct net_device_stats netdev_stats; struct spider_net_extra_stats spider_stats; - - struct spider_net_descr descr[0]; + struct spider_net_options options; }; #define pr_err(fmt,arg...) \ diff --git a/drivers/net/spider_net_ethtool.c b/drivers/net/spider_net_ethtool.c index 91b995102915..6bcf03fc89be 100644 --- a/drivers/net/spider_net_ethtool.c +++ b/drivers/net/spider_net_ethtool.c @@ -158,9 +158,9 @@ spider_net_ethtool_get_ringparam(struct net_device *netdev, struct spider_net_card *card = netdev->priv; ering->tx_max_pending = SPIDER_NET_TX_DESCRIPTORS_MAX; - ering->tx_pending = card->num_tx_desc; + ering->tx_pending = card->tx_chain.num_desc; ering->rx_max_pending = SPIDER_NET_RX_DESCRIPTORS_MAX; - ering->rx_pending = card->num_rx_desc; + ering->rx_pending = card->rx_chain.num_desc; } static int spider_net_get_stats_count(struct net_device *netdev) -- 2.20.1