New driver "sfc" for Solarstorm SFC4000 controller.
The driver supports the 10Xpress PHY and XFP modules on our reference
designs SFE4001 and SFE4002 and the SMC models SMC10GPCIe-XFP and
SMC10GPCIe-10BT.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/net/sfc/tx.c b/drivers/net/sfc/tx.c
new file mode 100644
index 0000000..fbb866b
--- /dev/null
+++ b/drivers/net/sfc/tx.c
@@ -0,0 +1,452 @@
+/****************************************************************************
+ * Driver for Solarflare Solarstorm network controllers and boards
+ * Copyright 2005-2006 Fen Systems Ltd.
+ * Copyright 2005-2008 Solarflare Communications Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation, incorporated herein by reference.
+ */
+
+#include <linux/pci.h>
+#include <linux/tcp.h>
+#include <linux/ip.h>
+#include <linux/in.h>
+#include <linux/if_ether.h>
+#include <linux/highmem.h>
+#include "net_driver.h"
+#include "tx.h"
+#include "efx.h"
+#include "falcon.h"
+#include "workarounds.h"
+
+/*
+ * TX descriptor ring full threshold
+ *
+ * The tx_queue descriptor ring fill-level must fall below this value
+ * before we restart the netif queue
+ */
+#define EFX_NETDEV_TX_THRESHOLD(_tx_queue) \
+ (_tx_queue->efx->type->txd_ring_mask / 2u)
+
+/* We want to be able to nest calls to netif_stop_queue(), since each
+ * channel can have an individual stop on the queue.
+ */
+void efx_stop_queue(struct efx_nic *efx)
+{
+ spin_lock_bh(&efx->netif_stop_lock);
+ EFX_TRACE(efx, "stop TX queue\n");
+
+ atomic_inc(&efx->netif_stop_count);
+ netif_stop_queue(efx->net_dev);
+
+ spin_unlock_bh(&efx->netif_stop_lock);
+}
+
+/* Wake netif's TX queue
+ * We want to be able to nest calls to netif_stop_queue(), since each
+ * channel can have an individual stop on the queue.
+ */
+inline void efx_wake_queue(struct efx_nic *efx)
+{
+ local_bh_disable();
+ if (atomic_dec_and_lock(&efx->netif_stop_count,
+ &efx->netif_stop_lock)) {
+ EFX_TRACE(efx, "waking TX queue\n");
+ netif_wake_queue(efx->net_dev);
+ spin_unlock(&efx->netif_stop_lock);
+ }
+ local_bh_enable();
+}
+
+static inline void efx_dequeue_buffer(struct efx_tx_queue *tx_queue,
+ struct efx_tx_buffer *buffer)
+{
+ if (buffer->unmap_len) {
+ struct pci_dev *pci_dev = tx_queue->efx->pci_dev;
+ if (buffer->unmap_single)
+ pci_unmap_single(pci_dev, buffer->unmap_addr,
+ buffer->unmap_len, PCI_DMA_TODEVICE);
+ else
+ pci_unmap_page(pci_dev, buffer->unmap_addr,
+ buffer->unmap_len, PCI_DMA_TODEVICE);
+ buffer->unmap_len = 0;
+ buffer->unmap_single = 0;
+ }
+
+ if (buffer->skb) {
+ dev_kfree_skb_any((struct sk_buff *) buffer->skb);
+ buffer->skb = NULL;
+ EFX_TRACE(tx_queue->efx, "TX queue %d transmission id %x "
+ "complete\n", tx_queue->queue, read_ptr);
+ }
+}
+
+
+/*
+ * Add a socket buffer to a TX queue
+ *
+ * This maps all fragments of a socket buffer for DMA and adds them to
+ * the TX queue. The queue's insert pointer will be incremented by
+ * the number of fragments in the socket buffer.
+ *
+ * If any DMA mapping fails, any mapped fragments will be unmapped,
+ * the queue's insert pointer will be restored to its original value.
+ *
+ * Returns NETDEV_TX_OK or NETDEV_TX_BUSY
+ * You must hold netif_tx_lock() to call this function.
+ */
+static inline int efx_enqueue_skb(struct efx_tx_queue *tx_queue,
+ const struct sk_buff *skb)
+{
+ struct efx_nic *efx = tx_queue->efx;
+ struct pci_dev *pci_dev = efx->pci_dev;
+ struct efx_tx_buffer *buffer;
+ skb_frag_t *fragment;
+ struct page *page;
+ int page_offset;
+ unsigned int len, unmap_len = 0, fill_level, insert_ptr, misalign;
+ dma_addr_t dma_addr, unmap_addr = 0;
+ unsigned int dma_len;
+ unsigned unmap_single;
+ int q_space, i = 0;
+ int rc = NETDEV_TX_OK;
+
+ EFX_BUG_ON_PARANOID(tx_queue->write_count != tx_queue->insert_count);
+
+ /* Get size of the initial fragment */
+ len = skb_headlen(skb);
+
+ fill_level = tx_queue->insert_count - tx_queue->old_read_count;
+ q_space = efx->type->txd_ring_mask - 1 - fill_level;
+
+ /* Map for DMA. Use pci_map_single rather than pci_map_page
+ * since this is more efficient on machines with sparse
+ * memory.
+ */
+ unmap_single = 1;
+ dma_addr = pci_map_single(pci_dev, skb->data, len, PCI_DMA_TODEVICE);
+
+ /* Process all fragments */
+ while (1) {
+ if (unlikely(pci_dma_mapping_error(dma_addr)))
+ goto pci_err;
+
+ /* Store fields for marking in the per-fragment final
+ * descriptor */
+ unmap_len = len;
+ unmap_addr = dma_addr;
+
+ /* Add to TX queue, splitting across DMA boundaries */
+ do {
+ if (unlikely(q_space-- <= 0)) {
+ /* It might be that completions have
+ * happened since the xmit path last
+ * checked. Update the xmit path's
+ * copy of read_count.
+ */
+ ++tx_queue->stopped;
+ /* This memory barrier protects the
+ * change of stopped from the access
+ * of read_count. */
+ smp_mb();
+ tx_queue->old_read_count =
+ *(volatile unsigned *)
+ &tx_queue->read_count;
+ fill_level = (tx_queue->insert_count
+ - tx_queue->old_read_count);
+ q_space = (efx->type->txd_ring_mask - 1 -
+ fill_level);
+ if (unlikely(q_space-- <= 0))
+ goto stop;
+ smp_mb();
+ --tx_queue->stopped;
+ }
+
+ insert_ptr = (tx_queue->insert_count &
+ efx->type->txd_ring_mask);
+ buffer = &tx_queue->buffer[insert_ptr];
+ EFX_BUG_ON_PARANOID(buffer->skb);
+ EFX_BUG_ON_PARANOID(buffer->len);
+ EFX_BUG_ON_PARANOID(buffer->continuation != 1);
+ EFX_BUG_ON_PARANOID(buffer->unmap_len);
+
+ dma_len = (((~dma_addr) & efx->type->tx_dma_mask) + 1);
+ if (likely(dma_len > len))
+ dma_len = len;
+
+ misalign = (unsigned)dma_addr & efx->type->bug5391_mask;
+ if (misalign && dma_len + misalign > 512)
+ dma_len = 512 - misalign;
+
+ /* Fill out per descriptor fields */
+ buffer->len = dma_len;
+ buffer->dma_addr = dma_addr;
+ len -= dma_len;
+ dma_addr += dma_len;
+ ++tx_queue->insert_count;
+ } while (len);
+
+ /* Transfer ownership of the unmapping to the final buffer */
+ buffer->unmap_addr = unmap_addr;
+ buffer->unmap_single = unmap_single;
+ buffer->unmap_len = unmap_len;
+ unmap_len = 0;
+
+ /* Get address and size of next fragment */
+ if (i >= skb_shinfo(skb)->nr_frags)
+ break;
+ fragment = &skb_shinfo(skb)->frags[i];
+ len = fragment->size;
+ page = fragment->page;
+ page_offset = fragment->page_offset;
+ i++;
+ /* Map for DMA */
+ unmap_single = 0;
+ dma_addr = pci_map_page(pci_dev, page, page_offset, len,
+ PCI_DMA_TODEVICE);
+ }
+
+ /* Transfer ownership of the skb to the final buffer */
+ buffer->skb = skb;
+ buffer->continuation = 0;
+
+ /* Pass off to hardware */
+ falcon_push_buffers(tx_queue);
+
+ return NETDEV_TX_OK;
+
+ pci_err:
+ EFX_ERR_RL(efx, " TX queue %d could not map skb with %d bytes %d "
+ "fragments for DMA\n", tx_queue->queue, skb->len,
+ skb_shinfo(skb)->nr_frags + 1);
+
+ /* Mark the packet as transmitted, and free the SKB ourselves */
+ dev_kfree_skb_any((struct sk_buff *)skb);
+ goto unwind;
+
+ stop:
+ rc = NETDEV_TX_BUSY;
+
+ if (tx_queue->stopped == 1)
+ efx_stop_queue(efx);
+
+ unwind:
+ /* Work backwards until we hit the original insert pointer value */
+ while (tx_queue->insert_count != tx_queue->write_count) {
+ --tx_queue->insert_count;
+ insert_ptr = tx_queue->insert_count & efx->type->txd_ring_mask;
+ buffer = &tx_queue->buffer[insert_ptr];
+ efx_dequeue_buffer(tx_queue, buffer);
+ buffer->len = 0;
+ }
+
+ /* Free the fragment we were mid-way through pushing */
+ if (unmap_len)
+ pci_unmap_page(pci_dev, unmap_addr, unmap_len,
+ PCI_DMA_TODEVICE);
+
+ return rc;
+}
+
+/* Remove packets from the TX queue
+ *
+ * This removes packets from the TX queue, up to and including the
+ * specified index.
+ */
+static inline void efx_dequeue_buffers(struct efx_tx_queue *tx_queue,
+ unsigned int index)
+{
+ struct efx_nic *efx = tx_queue->efx;
+ unsigned int stop_index, read_ptr;
+ unsigned int mask = tx_queue->efx->type->txd_ring_mask;
+
+ stop_index = (index + 1) & mask;
+ read_ptr = tx_queue->read_count & mask;
+
+ while (read_ptr != stop_index) {
+ struct efx_tx_buffer *buffer = &tx_queue->buffer[read_ptr];
+ if (unlikely(buffer->len == 0)) {
+ EFX_ERR(tx_queue->efx, "TX queue %d spurious TX "
+ "completion id %x\n", tx_queue->queue,
+ read_ptr);
+ efx_schedule_reset(efx, RESET_TYPE_TX_SKIP);
+ return;
+ }
+
+ efx_dequeue_buffer(tx_queue, buffer);
+ buffer->continuation = 1;
+ buffer->len = 0;
+
+ ++tx_queue->read_count;
+ read_ptr = tx_queue->read_count & mask;
+ }
+}
+
+/* Initiate a packet transmission on the specified TX queue.
+ * Note that returning anything other than NETDEV_TX_OK will cause the
+ * OS to free the skb.
+ *
+ * This function is split out from efx_hard_start_xmit to allow the
+ * loopback test to direct packets via specific TX queues. It is
+ * therefore a non-static inline, so as not to penalise performance
+ * for non-loopback transmissions.
+ *
+ * Context: netif_tx_lock held
+ */
+inline int efx_xmit(struct efx_nic *efx,
+ struct efx_tx_queue *tx_queue, struct sk_buff *skb)
+{
+ int rc;
+
+ /* Map fragments for DMA and add to TX queue */
+ rc = efx_enqueue_skb(tx_queue, skb);
+ if (unlikely(rc != NETDEV_TX_OK))
+ goto out;
+
+ /* Update last TX timer */
+ efx->net_dev->trans_start = jiffies;
+
+ out:
+ return rc;
+}
+
+/* Initiate a packet transmission. We use one channel per CPU
+ * (sharing when we have more CPUs than channels). On Falcon, the TX
+ * completion events will be directed back to the CPU that transmitted
+ * the packet, which should be cache-efficient.
+ *
+ * Context: non-blocking.
+ * Note that returning anything other than NETDEV_TX_OK will cause the
+ * OS to free the skb.
+ */
+int efx_hard_start_xmit(struct sk_buff *skb, struct net_device *net_dev)
+{
+ struct efx_nic *efx = net_dev->priv;
+ return efx_xmit(efx, &efx->tx_queue[0], skb);
+}
+
+void efx_xmit_done(struct efx_tx_queue *tx_queue, unsigned int index)
+{
+ unsigned fill_level;
+ struct efx_nic *efx = tx_queue->efx;
+
+ EFX_BUG_ON_PARANOID(index > efx->type->txd_ring_mask);
+
+ efx_dequeue_buffers(tx_queue, index);
+
+ /* See if we need to restart the netif queue. This barrier
+ * separates the update of read_count from the test of
+ * stopped. */
+ smp_mb();
+ if (unlikely(tx_queue->stopped)) {
+ fill_level = tx_queue->insert_count - tx_queue->read_count;
+ if (fill_level < EFX_NETDEV_TX_THRESHOLD(tx_queue)) {
+ EFX_BUG_ON_PARANOID(!NET_DEV_REGISTERED(efx));
+
+ /* Do this under netif_tx_lock(), to avoid racing
+ * with efx_xmit(). */
+ netif_tx_lock(efx->net_dev);
+ if (tx_queue->stopped) {
+ tx_queue->stopped = 0;
+ efx_wake_queue(efx);
+ }
+ netif_tx_unlock(efx->net_dev);
+ }
+ }
+}
+
+int efx_probe_tx_queue(struct efx_tx_queue *tx_queue)
+{
+ struct efx_nic *efx = tx_queue->efx;
+ unsigned int txq_size;
+ int i, rc;
+
+ EFX_LOG(efx, "creating TX queue %d\n", tx_queue->queue);
+
+ /* Allocate software ring */
+ txq_size = (efx->type->txd_ring_mask + 1) * sizeof(*tx_queue->buffer);
+ tx_queue->buffer = kzalloc(txq_size, GFP_KERNEL);
+ if (!tx_queue->buffer) {
+ rc = -ENOMEM;
+ goto fail1;
+ }
+ for (i = 0; i <= efx->type->txd_ring_mask; ++i)
+ tx_queue->buffer[i].continuation = 1;
+
+ /* Allocate hardware ring */
+ rc = falcon_probe_tx(tx_queue);
+ if (rc)
+ goto fail2;
+
+ return 0;
+
+ fail2:
+ kfree(tx_queue->buffer);
+ tx_queue->buffer = NULL;
+ fail1:
+ tx_queue->used = 0;
+
+ return rc;
+}
+
+int efx_init_tx_queue(struct efx_tx_queue *tx_queue)
+{
+ EFX_LOG(tx_queue->efx, "initialising TX queue %d\n", tx_queue->queue);
+
+ tx_queue->insert_count = 0;
+ tx_queue->write_count = 0;
+ tx_queue->read_count = 0;
+ tx_queue->old_read_count = 0;
+ BUG_ON(tx_queue->stopped);
+
+ /* Set up TX descriptor ring */
+ return falcon_init_tx(tx_queue);
+}
+
+void efx_release_tx_buffers(struct efx_tx_queue *tx_queue)
+{
+ struct efx_tx_buffer *buffer;
+
+ if (!tx_queue->buffer)
+ return;
+
+ /* Free any buffers left in the ring */
+ while (tx_queue->read_count != tx_queue->write_count) {
+ buffer = &tx_queue->buffer[tx_queue->read_count &
+ tx_queue->efx->type->txd_ring_mask];
+ efx_dequeue_buffer(tx_queue, buffer);
+ buffer->continuation = 1;
+ buffer->len = 0;
+
+ ++tx_queue->read_count;
+ }
+}
+
+void efx_fini_tx_queue(struct efx_tx_queue *tx_queue)
+{
+ EFX_LOG(tx_queue->efx, "shutting down TX queue %d\n", tx_queue->queue);
+
+ /* Flush TX queue, remove descriptor ring */
+ falcon_fini_tx(tx_queue);
+
+ efx_release_tx_buffers(tx_queue);
+
+ /* Release queue's stop on port, if any */
+ if (tx_queue->stopped) {
+ tx_queue->stopped = 0;
+ efx_wake_queue(tx_queue->efx);
+ }
+}
+
+void efx_remove_tx_queue(struct efx_tx_queue *tx_queue)
+{
+ EFX_LOG(tx_queue->efx, "destroying TX queue %d\n", tx_queue->queue);
+ falcon_remove_tx(tx_queue);
+
+ kfree(tx_queue->buffer);
+ tx_queue->buffer = NULL;
+ tx_queue->used = 0;
+}
+
+