Conversion of Rx data buffers to PCI DMA - endianness is kept in a fscked state as it is in the original code (will be adressed in a later patch); - rtl8169_rx_clear() walks the buffer ring and releases the allocated data buffers. It needs to be used in two places: - rtl8169_init_ring() failure path; - normal device release (i.e. rtl8169_close); - rtl8169_free_rx_skb() releases a Rx data buffer. Mostly an helper for rtl8169_rx_clear(). As such it must: - unmap the memory area; - release the skb; - prevent the ring descriptor from being used again; - rtl8169_alloc_rx_skb() prepares a Rx data buffer for use. As such it must: - allocate an skb; - map the memory area; - reflect the changes in the ring descriptor. This function is balanced by rtl8169_free_rx_skb(). - rtl8169_unmap_rx() simply helps with the 80-columns limit. - rtl8169_rx_fill() walks a given range of the buffer ring and try to turn any descriptor into a ready to use one. It returns the count of modified descriptors and exits if an allocation fails. It can be seen as balanced by rtl8169_rx_clear(). Motivation: - partially abstract the (usually big) piece of code for the refill logic at the end of the Rx interrupt; - factorize the refill logic and the initial ring setup. - simple conversion of rtl8169_rx_interrupt() without rx_copybreak (will be adressed in a later patch). drivers/net/r8169.c | 235 +++++++++++++++++++++++++++++++++++----------------- 1 files changed, 161 insertions(+), 74 deletions(-) diff -puN drivers/net/r8169.c~r8169-dma-api-data-buffers drivers/net/r8169.c --- linux-2.6.0-test9/drivers/net/r8169.c~r8169-dma-api-data-buffers 2003-11-19 21:26:45.000000000 +0100 +++ linux-2.6.0-test9-fr/drivers/net/r8169.c 2003-11-20 00:45:00.000000000 +0100 @@ -279,15 +279,15 @@ struct rtl8169_private { struct net_device_stats stats; /* statistics of net device */ spinlock_t lock; /* spin lock flag */ int chipset; - unsigned long cur_rx; /* Index into the Rx descriptor buffer of next Rx pkt. */ - unsigned long cur_tx; /* Index into the Tx descriptor buffer of next Rx pkt. */ - unsigned long dirty_tx; + u32 cur_rx; /* Index into the Rx descriptor buffer of next Rx pkt. */ + u32 cur_tx; /* Index into the Tx descriptor buffer of next Rx pkt. */ + u32 dirty_rx; + u32 dirty_tx; struct TxDesc *TxDescArray; /* Index of 256-alignment Tx Descriptor buffer */ struct RxDesc *RxDescArray; /* Index of 256-alignment Rx Descriptor buffer */ dma_addr_t TxPhyAddr; dma_addr_t RxPhyAddr; - unsigned char *RxBufferRings; /* Index of Rx Buffer */ - unsigned char *RxBufferRing[NUM_RX_DESC]; /* Index of Rx Buffer array */ + struct sk_buff *Rx_skbuff[NUM_RX_DESC]; /* Rx data buffers */ struct sk_buff *Tx_skbuff[NUM_TX_DESC]; /* Index of Transmit data buffer */ }; @@ -756,37 +756,119 @@ rtl8169_hw_start(struct net_device *dev) } -static int rtl8169_init_ring(struct net_device *dev) +static inline void rtl8169_make_unusable_by_asic(struct RxDesc *desc) +{ + desc->buf_addr = 0xdeadbeef; + desc->status = EORbit; +} + +static void rtl8169_free_rx_skb(struct pci_dev *pdev, struct sk_buff **sk_buff, + struct RxDesc *desc) +{ + pci_unmap_single(pdev, desc->buf_addr, RX_BUF_SIZE, PCI_DMA_FROMDEVICE); + dev_kfree_skb(*sk_buff); + *sk_buff = NULL; + rtl8169_make_unusable_by_asic(desc); +} + +static inline void rtl8169_give_to_asic(struct RxDesc *desc, dma_addr_t mapping) +{ + desc->buf_addr = mapping; + desc->status = OWNbit + RX_BUF_SIZE; +} + +static int rtl8169_alloc_rx_skb(struct pci_dev *pdev, struct net_device *dev, + struct sk_buff **sk_buff, struct RxDesc *desc) +{ + struct sk_buff *skb; + dma_addr_t mapping; + int ret = 0; + + skb = dev_alloc_skb(RX_BUF_SIZE); + if (!skb) + goto err_out; + + skb->dev = dev; + skb_reserve(skb, 2); + *sk_buff = skb; + + mapping = pci_map_single(pdev, skb->tail, RX_BUF_SIZE, + PCI_DMA_FROMDEVICE); + + rtl8169_give_to_asic(desc, mapping); + +out: + return ret; + +err_out: + ret = -ENOMEM; + rtl8169_make_unusable_by_asic(desc); + goto out; +} + +static void rtl8169_rx_clear(struct rtl8169_private *tp) { - struct rtl8169_private *tp = dev->priv; int i; - tp->RxBufferRings = kmalloc(RX_BUF_SIZE * NUM_RX_DESC, GFP_KERNEL); - if (tp->RxBufferRings == NULL) { - printk(KERN_INFO "Allocate RxBufferRing failed\n"); - return -ENOMEM; + for (i = 0; i < NUM_RX_DESC; i++) { + if (tp->Rx_skbuff[i]) { + rtl8169_free_rx_skb(tp->pci_dev, tp->Rx_skbuff + i, + tp->RxDescArray + i); + } } +} - tp->cur_rx = 0; - tp->cur_tx = 0; - tp->dirty_tx = 0; +static u32 rtl8169_rx_fill(struct rtl8169_private *tp, struct net_device *dev, + u32 start, u32 end) +{ + u32 cur; + + for (cur = start; end - start > 0; cur++) { + int ret, i = cur % NUM_RX_DESC; + + if (tp->Rx_skbuff[i]) + continue; + + ret = rtl8169_alloc_rx_skb(tp->pci_dev, dev, tp->Rx_skbuff + i, + tp->RxDescArray + i); + if (ret < 0) + break; + } + return cur - start; +} + +static inline void rtl8169_mark_as_last_descriptor(struct RxDesc *desc) +{ + desc->status |= EORbit; +} + +static inline void rtl8169_unmark_as_last_descriptor(struct RxDesc *desc) +{ + desc->status &= ~EORbit; +} + +static int rtl8169_init_ring(struct net_device *dev) +{ + struct rtl8169_private *tp = dev->priv; + + tp->cur_rx = tp->dirty_rx = 0; + tp->cur_tx = tp->dirty_tx = 0; memset(tp->TxDescArray, 0x0, NUM_TX_DESC * sizeof (struct TxDesc)); memset(tp->RxDescArray, 0x0, NUM_RX_DESC * sizeof (struct RxDesc)); - for (i = 0; i < NUM_TX_DESC; i++) { - tp->Tx_skbuff[i] = NULL; - } - for (i = 0; i < NUM_RX_DESC; i++) { - if (i == (NUM_RX_DESC - 1)) - tp->RxDescArray[i].status = - (OWNbit | EORbit) + RX_BUF_SIZE; - else - tp->RxDescArray[i].status = OWNbit + RX_BUF_SIZE; + memset(tp->Tx_skbuff, 0x0, NUM_TX_DESC * sizeof(struct sk_buff *)); + memset(tp->Rx_skbuff, 0x0, NUM_RX_DESC * sizeof(struct sk_buff *)); + + if (rtl8169_rx_fill(tp, dev, 0, NUM_RX_DESC) != NUM_RX_DESC) + goto err_out; + + rtl8169_mark_as_last_descriptor(tp->RxDescArray + NUM_RX_DESC - 1); - tp->RxBufferRing[i] = &(tp->RxBufferRings[i * RX_BUF_SIZE]); - tp->RxDescArray[i].buf_addr = virt_to_bus(tp->RxBufferRing[i]); - } return 0; + +err_out: + rtl8169_rx_clear(tp); + return -ENOMEM; } static void @@ -906,70 +988,77 @@ rtl8169_tx_interrupt(struct net_device * } } +static inline void rtl8169_unmap_rx(struct pci_dev *pdev, struct RxDesc *desc) +{ + pci_dma_sync_single(pdev, le32_to_cpu(desc->buf_addr), RX_BUF_SIZE, + PCI_DMA_FROMDEVICE); + pci_unmap_single(pdev, le32_to_cpu(desc->buf_addr), RX_BUF_SIZE, + PCI_DMA_FROMDEVICE); +} + static void rtl8169_rx_interrupt(struct net_device *dev, struct rtl8169_private *tp, void *ioaddr) { - int cur_rx; - struct sk_buff *skb; - int pkt_size = 0; + int cur_rx, delta; assert(dev != NULL); assert(tp != NULL); assert(ioaddr != NULL); - cur_rx = tp->cur_rx; + cur_rx = tp->cur_rx % RX_BUF_SIZE; while ((tp->RxDescArray[cur_rx].status & OWNbit) == 0) { + u32 status = tp->RxDescArray[cur_rx].status; - if (tp->RxDescArray[cur_rx].status & RxRES) { + if (status & RxRES) { printk(KERN_INFO "%s: Rx ERROR!!!\n", dev->name); tp->stats.rx_errors++; - if (tp->RxDescArray[cur_rx].status & (RxRWT | RxRUNT)) + if (status & (RxRWT | RxRUNT)) tp->stats.rx_length_errors++; - if (tp->RxDescArray[cur_rx].status & RxCRC) + if (status & RxCRC) tp->stats.rx_crc_errors++; } else { - pkt_size = - (int) (tp->RxDescArray[cur_rx]. - status & 0x00001FFF) - 4; - skb = dev_alloc_skb(pkt_size + 2); - if (skb != NULL) { - skb->dev = dev; - skb_reserve(skb, 2); // 16 byte align the IP fields. // - eth_copy_and_sum(skb, tp->RxBufferRing[cur_rx], - pkt_size, 0); - skb_put(skb, pkt_size); - skb->protocol = eth_type_trans(skb, dev); - netif_rx(skb); - - if (cur_rx == (NUM_RX_DESC - 1)) - tp->RxDescArray[cur_rx].status = - (OWNbit | EORbit) + RX_BUF_SIZE; - else - tp->RxDescArray[cur_rx].status = - OWNbit + RX_BUF_SIZE; - - tp->RxDescArray[cur_rx].buf_addr = - virt_to_bus(tp->RxBufferRing[cur_rx]); - dev->last_rx = jiffies; - tp->stats.rx_bytes += pkt_size; - tp->stats.rx_packets++; - } else { - printk(KERN_WARNING - "%s: Memory squeeze, deferring packet.\n", - dev->name); - /* We should check that some rx space is free. - If not, free one and mark stats->rx_dropped++. */ - tp->stats.rx_dropped++; - } - } + struct sk_buff *skb = tp->Rx_skbuff[cur_rx]; + int pkt_size = (status & 0x00001FFF) - 4; + + rtl8169_unmap_rx(tp->pci_dev, tp->RxDescArray + cur_rx); + + skb_put(skb, pkt_size); + skb->protocol = eth_type_trans(skb, dev); + netif_rx(skb); - cur_rx = (cur_rx + 1) % NUM_RX_DESC; + tp->Rx_skbuff[cur_rx] = NULL; + dev->last_rx = jiffies; + tp->stats.rx_bytes += pkt_size; + tp->stats.rx_packets++; + } + + tp->cur_rx++; + cur_rx = tp->cur_rx % NUM_RX_DESC; } - tp->cur_rx = cur_rx; + delta = rtl8169_rx_fill(tp, dev, tp->dirty_rx, tp->cur_rx); + if (delta > 0) { + u32 old_last = (tp->dirty_rx - 1) % NUM_RX_DESC; + + tp->dirty_rx += delta; + rtl8169_mark_as_last_descriptor(tp->RxDescArray + + (tp->dirty_rx - 1)%NUM_RX_DESC); + rtl8169_unmark_as_last_descriptor(tp->RxDescArray + old_last); + } else if (delta < 0) + printk(KERN_INFO "%s: no Rx buffer allocated\n", dev->name); + + /* + * FIXME: until there is periodic timer to try and refill the ring, + * a temporary shortage may definitely kill the Rx process. + * - disable the asic to try and avoid an overflow and kick it again + * after refill ? + * - how do others driver handle this condition (Uh oh...). + */ + if (tp->dirty_rx + NUM_RX_DESC == tp->cur_rx) + printk(KERN_EMERG "%s: Rx buffers exhausted\n", dev->name); } /* The interrupt handler does all of the Rx thread work and cleans up after the Tx thread. */ @@ -1032,7 +1121,6 @@ rtl8169_close(struct net_device *dev) struct rtl8169_private *tp = dev->priv; struct pci_dev *pdev = tp->pci_dev; void *ioaddr = tp->mmio_addr; - int i; netif_stop_queue(dev); @@ -1054,16 +1142,15 @@ rtl8169_close(struct net_device *dev) free_irq(dev->irq, dev); rtl8169_tx_clear(tp); + + rtl8169_rx_clear(tp); + pci_free_consistent(pdev, R8169_RX_RING_BYTES, tp->RxDescArray, tp->RxPhyAddr); pci_free_consistent(pdev, R8169_TX_RING_BYTES, tp->TxDescArray, tp->TxPhyAddr); tp->TxDescArray = NULL; tp->RxDescArray = NULL; - kfree(tp->RxBufferRings); - for (i = 0; i < NUM_RX_DESC; i++) { - tp->RxBufferRing[i] = NULL; - } return 0; } _