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>

1 files changed, 875 insertions, 0 deletions

diff --git a/drivers/net/sfc/rx.c b/drivers/net/sfc/rx.c
new file mode 100644
index 000000000000..551299b462ae
--- /dev/null
+++ b/drivers/net/sfc/rx.c
@@ -0,0 +1,875 @@
+/****************************************************************************
+ * 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/socket.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <net/ip.h>
+#include <net/checksum.h>
+#include "net_driver.h"
+#include "rx.h"
+#include "efx.h"
+#include "falcon.h"
+#include "workarounds.h"
+
+/* Number of RX descriptors pushed at once. */
+#define EFX_RX_BATCH  8
+
+/* Size of buffer allocated for skb header area. */
+#define EFX_SKB_HEADERS  64u
+
+/*
+ * rx_alloc_method - RX buffer allocation method
+ *
+ * This driver supports two methods for allocating and using RX buffers:
+ * each RX buffer may be backed by an skb or by an order-n page.
+ *
+ * When LRO is in use then the second method has a lower overhead,
+ * since we don't have to allocate then free skbs on reassembled frames.
+ *
+ * Values:
+ *   - RX_ALLOC_METHOD_AUTO = 0
+ *   - RX_ALLOC_METHOD_SKB  = 1
+ *   - RX_ALLOC_METHOD_PAGE = 2
+ *
+ * The heuristic for %RX_ALLOC_METHOD_AUTO is a simple hysteresis count
+ * controlled by the parameters below.
+ *
+ *   - Since pushing and popping descriptors are separated by the rx_queue
+ *     size, so the watermarks should be ~rxd_size.
+ *   - The performance win by using page-based allocation for LRO is less
+ *     than the performance hit of using page-based allocation of non-LRO,
+ *     so the watermarks should reflect this.
+ *
+ * Per channel we maintain a single variable, updated by each channel:
+ *
+ *   rx_alloc_level += (lro_performed ? RX_ALLOC_FACTOR_LRO :
+ *                      RX_ALLOC_FACTOR_SKB)
+ * Per NAPI poll interval, we constrain rx_alloc_level to 0..MAX (which
+ * limits the hysteresis), and update the allocation strategy:
+ *
+ *   rx_alloc_method = (rx_alloc_level > RX_ALLOC_LEVEL_LRO ?
+ *                      RX_ALLOC_METHOD_PAGE : RX_ALLOC_METHOD_SKB)
+ */
+static int rx_alloc_method = RX_ALLOC_METHOD_PAGE;
+
+#define RX_ALLOC_LEVEL_LRO 0x2000
+#define RX_ALLOC_LEVEL_MAX 0x3000
+#define RX_ALLOC_FACTOR_LRO 1
+#define RX_ALLOC_FACTOR_SKB (-2)
+
+/* This is the percentage fill level below which new RX descriptors
+ * will be added to the RX descriptor ring.
+ */
+static unsigned int rx_refill_threshold = 90;
+
+/* This is the percentage fill level to which an RX queue will be refilled
+ * when the "RX refill threshold" is reached.
+ */
+static unsigned int rx_refill_limit = 95;
+
+/*
+ * RX maximum head room required.
+ *
+ * This must be at least 1 to prevent overflow and at least 2 to allow
+ * pipelined receives.
+ */
+#define EFX_RXD_HEAD_ROOM 2
+
+/* Macros for zero-order pages (potentially) containing multiple RX buffers */
+#define RX_DATA_OFFSET(_data)                           \
+        (((unsigned long) (_data)) & (PAGE_SIZE-1))
+#define RX_BUF_OFFSET(_rx_buf)                          \
+        RX_DATA_OFFSET((_rx_buf)->data)
+
+#define RX_PAGE_SIZE(_efx)                              \
+        (PAGE_SIZE * (1u << (_efx)->rx_buffer_order))
+
+
+/**************************************************************************
+ *
+ * Linux generic LRO handling
+ *
+ **************************************************************************
+ */
+
+static int efx_lro_get_skb_hdr(struct sk_buff *skb, void **ip_hdr,
+                               void **tcpudp_hdr, u64 *hdr_flags, void *priv)
+{
+        struct efx_channel *channel = (struct efx_channel *)priv;
+        struct iphdr *iph;
+        struct tcphdr *th;
+
+        iph = (struct iphdr *)skb->data;
+        if (skb->protocol != htons(ETH_P_IP) || iph->protocol != IPPROTO_TCP)
+                goto fail;
+
+        th = (struct tcphdr *)(skb->data + iph->ihl * 4);
+
+        *tcpudp_hdr = th;
+        *ip_hdr = iph;
+        *hdr_flags = LRO_IPV4 | LRO_TCP;
+
+        channel->rx_alloc_level += RX_ALLOC_FACTOR_LRO;
+        return 0;
+fail:
+        channel->rx_alloc_level += RX_ALLOC_FACTOR_SKB;
+        return -1;
+}
+
+static int efx_get_frag_hdr(struct skb_frag_struct *frag, void **mac_hdr,
+                            void **ip_hdr, void **tcpudp_hdr, u64 *hdr_flags,
+                            void *priv)
+{
+        struct efx_channel *channel = (struct efx_channel *)priv;
+        struct ethhdr *eh;
+        struct iphdr *iph;
+
+        /* We support EtherII and VLAN encapsulated IPv4 */
+        eh = (struct ethhdr *)(page_address(frag->page) + frag->page_offset);
+        *mac_hdr = eh;
+
+        if (eh->h_proto == htons(ETH_P_IP)) {
+                iph = (struct iphdr *)(eh + 1);
+        } else {
+                struct vlan_ethhdr *veh = (struct vlan_ethhdr *)eh;
+                if (veh->h_vlan_encapsulated_proto != htons(ETH_P_IP))
+                        goto fail;
+
+                iph = (struct iphdr *)(veh + 1);
+        }
+        *ip_hdr = iph;
+
+        /* We can only do LRO over TCP */
+        if (iph->protocol != IPPROTO_TCP)
+                goto fail;
+
+        *hdr_flags = LRO_IPV4 | LRO_TCP;
+        *tcpudp_hdr = (struct tcphdr *)((u8 *) iph + iph->ihl * 4);
+
+        channel->rx_alloc_level += RX_ALLOC_FACTOR_LRO;
+        return 0;
+ fail:
+        channel->rx_alloc_level += RX_ALLOC_FACTOR_SKB;
+        return -1;
+}
+
+int efx_lro_init(struct net_lro_mgr *lro_mgr, struct efx_nic *efx)
+{
+        size_t s = sizeof(struct net_lro_desc) * EFX_MAX_LRO_DESCRIPTORS;
+        struct net_lro_desc *lro_arr;
+
+        /* Allocate the LRO descriptors structure */
+        lro_arr = kzalloc(s, GFP_KERNEL);
+        if (lro_arr == NULL)
+                return -ENOMEM;
+
+        lro_mgr->lro_arr = lro_arr;
+        lro_mgr->max_desc = EFX_MAX_LRO_DESCRIPTORS;
+        lro_mgr->max_aggr = EFX_MAX_LRO_AGGR;
+        lro_mgr->frag_align_pad = EFX_PAGE_SKB_ALIGN;
+
+        lro_mgr->get_skb_header = efx_lro_get_skb_hdr;
+        lro_mgr->get_frag_header = efx_get_frag_hdr;
+        lro_mgr->dev = efx->net_dev;
+
+        lro_mgr->features = LRO_F_NAPI;
+
+        /* We can pass packets up with the checksum intact */
+        lro_mgr->ip_summed = CHECKSUM_UNNECESSARY;
+
+        lro_mgr->ip_summed_aggr = CHECKSUM_UNNECESSARY;
+
+        return 0;
+}
+
+void efx_lro_fini(struct net_lro_mgr *lro_mgr)
+{
+        kfree(lro_mgr->lro_arr);
+        lro_mgr->lro_arr = NULL;
+}
+
+/**
+ * efx_init_rx_buffer_skb - create new RX buffer using skb-based allocation
+ *
+ * @rx_queue:           Efx RX queue
+ * @rx_buf:             RX buffer structure to populate
+ *
+ * This allocates memory for a new receive buffer, maps it for DMA,
+ * and populates a struct efx_rx_buffer with the relevant
+ * information.  Return a negative error code or 0 on success.
+ */
+static inline int efx_init_rx_buffer_skb(struct efx_rx_queue *rx_queue,
+                                         struct efx_rx_buffer *rx_buf)
+{
+        struct efx_nic *efx = rx_queue->efx;
+        struct net_device *net_dev = efx->net_dev;
+        int skb_len = efx->rx_buffer_len;
+
+        rx_buf->skb = netdev_alloc_skb(net_dev, skb_len);
+        if (unlikely(!rx_buf->skb))
+                return -ENOMEM;
+
+        /* Adjust the SKB for padding and checksum */
+        skb_reserve(rx_buf->skb, NET_IP_ALIGN);
+        rx_buf->len = skb_len - NET_IP_ALIGN;
+        rx_buf->data = (char *)rx_buf->skb->data;
+        rx_buf->skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+        rx_buf->dma_addr = pci_map_single(efx->pci_dev,
+                                          rx_buf->data, rx_buf->len,
+                                          PCI_DMA_FROMDEVICE);
+
+        if (unlikely(pci_dma_mapping_error(rx_buf->dma_addr))) {
+                dev_kfree_skb_any(rx_buf->skb);
+                rx_buf->skb = NULL;
+                return -EIO;
+        }
+
+        return 0;
+}
+
+/**
+ * efx_init_rx_buffer_page - create new RX buffer using page-based allocation
+ *
+ * @rx_queue:           Efx RX queue
+ * @rx_buf:             RX buffer structure to populate
+ *
+ * This allocates memory for a new receive buffer, maps it for DMA,
+ * and populates a struct efx_rx_buffer with the relevant
+ * information.  Return a negative error code or 0 on success.
+ */
+static inline int efx_init_rx_buffer_page(struct efx_rx_queue *rx_queue,
+                                          struct efx_rx_buffer *rx_buf)
+{
+        struct efx_nic *efx = rx_queue->efx;
+        int bytes, space, offset;
+
+        bytes = efx->rx_buffer_len - EFX_PAGE_IP_ALIGN;
+
+        /* If there is space left in the previously allocated page,
+         * then use it. Otherwise allocate a new one */
+        rx_buf->page = rx_queue->buf_page;
+        if (rx_buf->page == NULL) {
+                dma_addr_t dma_addr;
+
+                rx_buf->page = alloc_pages(__GFP_COLD | __GFP_COMP | GFP_ATOMIC,
+                                           efx->rx_buffer_order);
+                if (unlikely(rx_buf->page == NULL))
+                        return -ENOMEM;
+
+                dma_addr = pci_map_page(efx->pci_dev, rx_buf->page,
+                                        0, RX_PAGE_SIZE(efx),
+                                        PCI_DMA_FROMDEVICE);
+
+                if (unlikely(pci_dma_mapping_error(dma_addr))) {
+                        __free_pages(rx_buf->page, efx->rx_buffer_order);
+                        rx_buf->page = NULL;
+                        return -EIO;
+                }
+
+                rx_queue->buf_page = rx_buf->page;
+                rx_queue->buf_dma_addr = dma_addr;
+                rx_queue->buf_data = ((char *) page_address(rx_buf->page) +
+                                      EFX_PAGE_IP_ALIGN);
+        }
+
+        offset = RX_DATA_OFFSET(rx_queue->buf_data);
+        rx_buf->len = bytes;
+        rx_buf->dma_addr = rx_queue->buf_dma_addr + offset;
+        rx_buf->data = rx_queue->buf_data;
+
+        /* Try to pack multiple buffers per page */
+        if (efx->rx_buffer_order == 0) {
+                /* The next buffer starts on the next 512 byte boundary */
+                rx_queue->buf_data += ((bytes + 0x1ff) & ~0x1ff);
+                offset += ((bytes + 0x1ff) & ~0x1ff);
+
+                space = RX_PAGE_SIZE(efx) - offset;
+                if (space >= bytes) {
+                        /* Refs dropped on kernel releasing each skb */
+                        get_page(rx_queue->buf_page);
+                        goto out;
+                }
+        }
+
+        /* This is the final RX buffer for this page, so mark it for
+         * unmapping */
+        rx_queue->buf_page = NULL;
+        rx_buf->unmap_addr = rx_queue->buf_dma_addr;
+
+ out:
+        return 0;
+}
+
+/* This allocates memory for a new receive buffer, maps it for DMA,
+ * and populates a struct efx_rx_buffer with the relevant
+ * information.
+ */
+static inline int efx_init_rx_buffer(struct efx_rx_queue *rx_queue,
+                                     struct efx_rx_buffer *new_rx_buf)
+{
+        int rc = 0;
+
+        if (rx_queue->channel->rx_alloc_push_pages) {
+                new_rx_buf->skb = NULL;
+                rc = efx_init_rx_buffer_page(rx_queue, new_rx_buf);
+                rx_queue->alloc_page_count++;
+        } else {
+                new_rx_buf->page = NULL;
+                rc = efx_init_rx_buffer_skb(rx_queue, new_rx_buf);
+                rx_queue->alloc_skb_count++;
+        }
+
+        if (unlikely(rc < 0))
+                EFX_LOG_RL(rx_queue->efx, "%s RXQ[%d] =%d\n", __func__,
+                           rx_queue->queue, rc);
+        return rc;
+}
+
+static inline void efx_unmap_rx_buffer(struct efx_nic *efx,
+                                       struct efx_rx_buffer *rx_buf)
+{
+        if (rx_buf->page) {
+                EFX_BUG_ON_PARANOID(rx_buf->skb);
+                if (rx_buf->unmap_addr) {
+                        pci_unmap_page(efx->pci_dev, rx_buf->unmap_addr,
+                                       RX_PAGE_SIZE(efx), PCI_DMA_FROMDEVICE);
+                        rx_buf->unmap_addr = 0;
+                }
+        } else if (likely(rx_buf->skb)) {
+                pci_unmap_single(efx->pci_dev, rx_buf->dma_addr,
+                                 rx_buf->len, PCI_DMA_FROMDEVICE);
+        }
+}
+
+static inline void efx_free_rx_buffer(struct efx_nic *efx,
+                                      struct efx_rx_buffer *rx_buf)
+{
+        if (rx_buf->page) {
+                __free_pages(rx_buf->page, efx->rx_buffer_order);
+                rx_buf->page = NULL;
+        } else if (likely(rx_buf->skb)) {
+                dev_kfree_skb_any(rx_buf->skb);
+                rx_buf->skb = NULL;
+        }
+}
+
+static inline void efx_fini_rx_buffer(struct efx_rx_queue *rx_queue,
+                                      struct efx_rx_buffer *rx_buf)
+{
+        efx_unmap_rx_buffer(rx_queue->efx, rx_buf);
+        efx_free_rx_buffer(rx_queue->efx, rx_buf);
+}
+
+/**
+ * efx_fast_push_rx_descriptors - push new RX descriptors quickly
+ * @rx_queue:           RX descriptor queue
+ * @retry:              Recheck the fill level
+ * This will aim to fill the RX descriptor queue up to
+ * @rx_queue->@fast_fill_limit. If there is insufficient atomic
+ * memory to do so, the caller should retry.
+ */
+static int __efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue,
+                                          int retry)
+{
+        struct efx_rx_buffer *rx_buf;
+        unsigned fill_level, index;
+        int i, space, rc = 0;
+
+        /* Calculate current fill level.  Do this outside the lock,
+         * because most of the time we'll end up not wanting to do the
+         * fill anyway.
+         */
+        fill_level = (rx_queue->added_count - rx_queue->removed_count);
+        EFX_BUG_ON_PARANOID(fill_level >
+                            rx_queue->efx->type->rxd_ring_mask + 1);
+
+        /* Don't fill if we don't need to */
+        if (fill_level >= rx_queue->fast_fill_trigger)
+                return 0;
+
+        /* Record minimum fill level */
+        if (unlikely(fill_level < rx_queue->min_fill))
+                if (fill_level)
+                        rx_queue->min_fill = fill_level;
+
+        /* Acquire RX add lock.  If this lock is contended, then a fast
+         * fill must already be in progress (e.g. in the refill
+         * tasklet), so we don't need to do anything
+         */
+        if (!spin_trylock_bh(&rx_queue->add_lock))
+                return -1;
+
+ retry:
+        /* Recalculate current fill level now that we have the lock */
+        fill_level = (rx_queue->added_count - rx_queue->removed_count);
+        EFX_BUG_ON_PARANOID(fill_level >
+                            rx_queue->efx->type->rxd_ring_mask + 1);
+        space = rx_queue->fast_fill_limit - fill_level;
+        if (space < EFX_RX_BATCH)
+                goto out_unlock;
+
+        EFX_TRACE(rx_queue->efx, "RX queue %d fast-filling descriptor ring from"
+                  " level %d to level %d using %s allocation\n",
+                  rx_queue->queue, fill_level, rx_queue->fast_fill_limit,
+                  rx_queue->channel->rx_alloc_push_pages ? "page" : "skb");
+
+        do {
+                for (i = 0; i < EFX_RX_BATCH; ++i) {
+                        index = (rx_queue->added_count &
+                                 rx_queue->efx->type->rxd_ring_mask);
+                        rx_buf = efx_rx_buffer(rx_queue, index);
+                        rc = efx_init_rx_buffer(rx_queue, rx_buf);
+                        if (unlikely(rc))
+                                goto out;
+                        ++rx_queue->added_count;
+                }
+        } while ((space -= EFX_RX_BATCH) >= EFX_RX_BATCH);
+
+        EFX_TRACE(rx_queue->efx, "RX queue %d fast-filled descriptor ring "
+                  "to level %d\n", rx_queue->queue,
+                  rx_queue->added_count - rx_queue->removed_count);
+
+ out:
+        /* Send write pointer to card. */
+        falcon_notify_rx_desc(rx_queue);
+
+        /* If the fast fill is running inside from the refill tasklet, then
+         * for SMP systems it may be running on a different CPU to
+         * RX event processing, which means that the fill level may now be
+         * out of date. */
+        if (unlikely(retry && (rc == 0)))
+                goto retry;
+
+ out_unlock:
+        spin_unlock_bh(&rx_queue->add_lock);
+
+        return rc;
+}
+
+/**
+ * efx_fast_push_rx_descriptors - push new RX descriptors quickly
+ * @rx_queue:           RX descriptor queue
+ *
+ * This will aim to fill the RX descriptor queue up to
+ * @rx_queue->@fast_fill_limit.  If there is insufficient memory to do so,
+ * it will schedule a work item to immediately continue the fast fill
+ */
+void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue)
+{
+        int rc;
+
+        rc = __efx_fast_push_rx_descriptors(rx_queue, 0);
+        if (unlikely(rc)) {
+                /* Schedule the work item to run immediately. The hope is
+                 * that work is immediately pending to free some memory
+                 * (e.g. an RX event or TX completion)
+                 */
+                efx_schedule_slow_fill(rx_queue, 0);
+        }
+}
+
+void efx_rx_work(struct work_struct *data)
+{
+        struct efx_rx_queue *rx_queue;
+        int rc;
+
+        rx_queue = container_of(data, struct efx_rx_queue, work.work);
+
+        if (unlikely(!rx_queue->channel->enabled))
+                return;
+
+        EFX_TRACE(rx_queue->efx, "RX queue %d worker thread executing on CPU "
+                  "%d\n", rx_queue->queue, raw_smp_processor_id());
+
+        ++rx_queue->slow_fill_count;
+        /* Push new RX descriptors, allowing at least 1 jiffy for
+         * the kernel to free some more memory. */
+        rc = __efx_fast_push_rx_descriptors(rx_queue, 1);
+        if (rc)
+                efx_schedule_slow_fill(rx_queue, 1);
+}
+
+static inline void efx_rx_packet__check_len(struct efx_rx_queue *rx_queue,
+                                            struct efx_rx_buffer *rx_buf,
+                                            int len, int *discard,
+                                            int *leak_packet)
+{
+        struct efx_nic *efx = rx_queue->efx;
+        unsigned max_len = rx_buf->len - efx->type->rx_buffer_padding;
+
+        if (likely(len <= max_len))
+                return;
+
+        /* The packet must be discarded, but this is only a fatal error
+         * if the caller indicated it was
+         */
+        *discard = 1;
+
+        if ((len > rx_buf->len) && EFX_WORKAROUND_8071(efx)) {
+                EFX_ERR_RL(efx, " RX queue %d seriously overlength "
+                           "RX event (0x%x > 0x%x+0x%x). Leaking\n",
+                           rx_queue->queue, len, max_len,
+                           efx->type->rx_buffer_padding);
+                /* If this buffer was skb-allocated, then the meta
+                 * data at the end of the skb will be trashed. So
+                 * we have no choice but to leak the fragment.
+                 */
+                *leak_packet = (rx_buf->skb != NULL);
+                efx_schedule_reset(efx, RESET_TYPE_RX_RECOVERY);
+        } else {
+                EFX_ERR_RL(efx, " RX queue %d overlength RX event "
+                           "(0x%x > 0x%x)\n", rx_queue->queue, len, max_len);
+        }
+
+        rx_queue->channel->n_rx_overlength++;
+}
+
+/* Pass a received packet up through the generic LRO stack
+ *
+ * Handles driverlink veto, and passes the fragment up via
+ * the appropriate LRO method
+ */
+static inline void efx_rx_packet_lro(struct efx_channel *channel,
+                                     struct efx_rx_buffer *rx_buf)
+{
+        struct net_lro_mgr *lro_mgr = &channel->lro_mgr;
+        void *priv = channel;
+
+        /* Pass the skb/page into the LRO engine */
+        if (rx_buf->page) {
+                struct skb_frag_struct frags;
+
+                frags.page = rx_buf->page;
+                frags.page_offset = RX_BUF_OFFSET(rx_buf);
+                frags.size = rx_buf->len;
+
+                lro_receive_frags(lro_mgr, &frags, rx_buf->len,
+                                  rx_buf->len, priv, 0);
+
+                EFX_BUG_ON_PARANOID(rx_buf->skb);
+                rx_buf->page = NULL;
+        } else {
+                EFX_BUG_ON_PARANOID(!rx_buf->skb);
+
+                lro_receive_skb(lro_mgr, rx_buf->skb, priv);
+                rx_buf->skb = NULL;
+        }
+}
+
+/* Allocate and construct an SKB around a struct page.*/
+static inline struct sk_buff *efx_rx_mk_skb(struct efx_rx_buffer *rx_buf,
+                                            struct efx_nic *efx,
+                                            int hdr_len)
+{
+        struct sk_buff *skb;
+
+        /* Allocate an SKB to store the headers */
+        skb = netdev_alloc_skb(efx->net_dev, hdr_len + EFX_PAGE_SKB_ALIGN);
+        if (unlikely(skb == NULL)) {
+                EFX_ERR_RL(efx, "RX out of memory for skb\n");
+                return NULL;
+        }
+
+        EFX_BUG_ON_PARANOID(skb_shinfo(skb)->nr_frags);
+        EFX_BUG_ON_PARANOID(rx_buf->len < hdr_len);
+
+        skb->ip_summed = CHECKSUM_UNNECESSARY;
+        skb_reserve(skb, EFX_PAGE_SKB_ALIGN);
+
+        skb->len = rx_buf->len;
+        skb->truesize = rx_buf->len + sizeof(struct sk_buff);
+        memcpy(skb->data, rx_buf->data, hdr_len);
+        skb->tail += hdr_len;
+
+        /* Append the remaining page onto the frag list */
+        if (unlikely(rx_buf->len > hdr_len)) {
+                struct skb_frag_struct *frag = skb_shinfo(skb)->frags;
+                frag->page = rx_buf->page;
+                frag->page_offset = RX_BUF_OFFSET(rx_buf) + hdr_len;
+                frag->size = skb->len - hdr_len;
+                skb_shinfo(skb)->nr_frags = 1;
+                skb->data_len = frag->size;
+        } else {
+                __free_pages(rx_buf->page, efx->rx_buffer_order);
+                skb->data_len = 0;
+        }
+
+        /* Ownership has transferred from the rx_buf to skb */
+        rx_buf->page = NULL;
+
+        /* Move past the ethernet header */
+        skb->protocol = eth_type_trans(skb, efx->net_dev);
+
+        return skb;
+}
+
+void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index,
+                   unsigned int len, int checksummed, int discard)
+{
+        struct efx_nic *efx = rx_queue->efx;
+        struct efx_rx_buffer *rx_buf;
+        int leak_packet = 0;
+
+        rx_buf = efx_rx_buffer(rx_queue, index);
+        EFX_BUG_ON_PARANOID(!rx_buf->data);
+        EFX_BUG_ON_PARANOID(rx_buf->skb && rx_buf->page);
+        EFX_BUG_ON_PARANOID(!(rx_buf->skb || rx_buf->page));
+
+        /* This allows the refill path to post another buffer.
+         * EFX_RXD_HEAD_ROOM ensures that the slot we are using
+         * isn't overwritten yet.
+         */
+        rx_queue->removed_count++;
+
+        /* Validate the length encoded in the event vs the descriptor pushed */
+        efx_rx_packet__check_len(rx_queue, rx_buf, len,
+                                 &discard, &leak_packet);
+
+        EFX_TRACE(efx, "RX queue %d received id %x at %llx+%x %s%s\n",
+                  rx_queue->queue, index,
+                  (unsigned long long)rx_buf->dma_addr, len,
+                  (checksummed ? " [SUMMED]" : ""),
+                  (discard ? " [DISCARD]" : ""));
+
+        /* Discard packet, if instructed to do so */
+        if (unlikely(discard)) {
+                if (unlikely(leak_packet))
+                        rx_queue->channel->n_skbuff_leaks++;
+                else
+                        /* We haven't called efx_unmap_rx_buffer yet,
+                         * so fini the entire rx_buffer here */
+                        efx_fini_rx_buffer(rx_queue, rx_buf);
+                return;
+        }
+
+        /* Release card resources - assumes all RX buffers consumed in-order
+         * per RX queue
+         */
+        efx_unmap_rx_buffer(efx, rx_buf);
+
+        /* Prefetch nice and early so data will (hopefully) be in cache by
+         * the time we look at it.
+         */
+        prefetch(rx_buf->data);
+
+        /* Pipeline receives so that we give time for packet headers to be
+         * prefetched into cache.
+         */
+        rx_buf->len = len;
+        if (rx_queue->channel->rx_pkt)
+                __efx_rx_packet(rx_queue->channel,
+                                rx_queue->channel->rx_pkt,
+                                rx_queue->channel->rx_pkt_csummed);
+        rx_queue->channel->rx_pkt = rx_buf;
+        rx_queue->channel->rx_pkt_csummed = checksummed;
+}
+
+/* Handle a received packet.  Second half: Touches packet payload. */
+void __efx_rx_packet(struct efx_channel *channel,
+                     struct efx_rx_buffer *rx_buf, int checksummed)
+{
+        struct efx_nic *efx = channel->efx;
+        struct sk_buff *skb;
+        int lro = efx->net_dev->features & NETIF_F_LRO;
+
+        if (rx_buf->skb) {
+                prefetch(skb_shinfo(rx_buf->skb));
+
+                skb_put(rx_buf->skb, rx_buf->len);
+
+                /* Move past the ethernet header. rx_buf->data still points
+                 * at the ethernet header */
+                rx_buf->skb->protocol = eth_type_trans(rx_buf->skb,
+                                                       efx->net_dev);
+        }
+
+        /* Both our generic-LRO and SFC-SSR support skb and page based
+         * allocation, but neither support switching from one to the
+         * other on the fly. If we spot that the allocation mode has
+         * changed, then flush the LRO state.
+         */
+        if (unlikely(channel->rx_alloc_pop_pages != (rx_buf->page != NULL))) {
+                efx_flush_lro(channel);
+                channel->rx_alloc_pop_pages = (rx_buf->page != NULL);
+        }
+        if (likely(checksummed && lro)) {
+                efx_rx_packet_lro(channel, rx_buf);
+                goto done;
+        }
+
+        /* Form an skb if required */
+        if (rx_buf->page) {
+                int hdr_len = min(rx_buf->len, EFX_SKB_HEADERS);
+                skb = efx_rx_mk_skb(rx_buf, efx, hdr_len);
+                if (unlikely(skb == NULL)) {
+                        efx_free_rx_buffer(efx, rx_buf);
+                        goto done;
+                }
+        } else {
+                /* We now own the SKB */
+                skb = rx_buf->skb;
+                rx_buf->skb = NULL;
+        }
+
+        EFX_BUG_ON_PARANOID(rx_buf->page);
+        EFX_BUG_ON_PARANOID(rx_buf->skb);
+        EFX_BUG_ON_PARANOID(!skb);
+
+        /* Set the SKB flags */
+        if (unlikely(!checksummed || !efx->rx_checksum_enabled))
+                skb->ip_summed = CHECKSUM_NONE;
+
+        /* Pass the packet up */
+        netif_receive_skb(skb);
+
+        /* Update allocation strategy method */
+        channel->rx_alloc_level += RX_ALLOC_FACTOR_SKB;
+
+        /* fall-thru */
+done:
+        efx->net_dev->last_rx = jiffies;
+}
+
+void efx_rx_strategy(struct efx_channel *channel)
+{
+        enum efx_rx_alloc_method method = rx_alloc_method;
+
+        /* Only makes sense to use page based allocation if LRO is enabled */
+        if (!(channel->efx->net_dev->features & NETIF_F_LRO)) {
+                method = RX_ALLOC_METHOD_SKB;
+        } else if (method == RX_ALLOC_METHOD_AUTO) {
+                /* Constrain the rx_alloc_level */
+                if (channel->rx_alloc_level < 0)
+                        channel->rx_alloc_level = 0;
+                else if (channel->rx_alloc_level > RX_ALLOC_LEVEL_MAX)
+                        channel->rx_alloc_level = RX_ALLOC_LEVEL_MAX;
+
+                /* Decide on the allocation method */
+                method = ((channel->rx_alloc_level > RX_ALLOC_LEVEL_LRO) ?
+                          RX_ALLOC_METHOD_PAGE : RX_ALLOC_METHOD_SKB);
+        }
+
+        /* Push the option */
+        channel->rx_alloc_push_pages = (method == RX_ALLOC_METHOD_PAGE);
+}
+
+int efx_probe_rx_queue(struct efx_rx_queue *rx_queue)
+{
+        struct efx_nic *efx = rx_queue->efx;
+        unsigned int rxq_size;
+        int rc;
+
+        EFX_LOG(efx, "creating RX queue %d\n", rx_queue->queue);
+
+        /* Allocate RX buffers */
+        rxq_size = (efx->type->rxd_ring_mask + 1) * sizeof(*rx_queue->buffer);
+        rx_queue->buffer = kzalloc(rxq_size, GFP_KERNEL);
+        if (!rx_queue->buffer) {
+                rc = -ENOMEM;
+                goto fail1;
+        }
+
+        rc = falcon_probe_rx(rx_queue);
+        if (rc)
+                goto fail2;
+
+        return 0;
+
+ fail2:
+        kfree(rx_queue->buffer);
+        rx_queue->buffer = NULL;
+ fail1:
+        rx_queue->used = 0;
+
+        return rc;
+}
+
+int efx_init_rx_queue(struct efx_rx_queue *rx_queue)
+{
+        struct efx_nic *efx = rx_queue->efx;
+        unsigned int max_fill, trigger, limit;
+
+        EFX_LOG(rx_queue->efx, "initialising RX queue %d\n", rx_queue->queue);
+
+        /* Initialise ptr fields */
+        rx_queue->added_count = 0;
+        rx_queue->notified_count = 0;
+        rx_queue->removed_count = 0;
+        rx_queue->min_fill = -1U;
+        rx_queue->min_overfill = -1U;
+
+        /* Initialise limit fields */
+        max_fill = efx->type->rxd_ring_mask + 1 - EFX_RXD_HEAD_ROOM;
+        trigger = max_fill * min(rx_refill_threshold, 100U) / 100U;
+        limit = max_fill * min(rx_refill_limit, 100U) / 100U;
+
+        rx_queue->max_fill = max_fill;
+        rx_queue->fast_fill_trigger = trigger;
+        rx_queue->fast_fill_limit = limit;
+
+        /* Set up RX descriptor ring */
+        return falcon_init_rx(rx_queue);
+}
+
+void efx_fini_rx_queue(struct efx_rx_queue *rx_queue)
+{
+        int i;
+        struct efx_rx_buffer *rx_buf;
+
+        EFX_LOG(rx_queue->efx, "shutting down RX queue %d\n", rx_queue->queue);
+
+        falcon_fini_rx(rx_queue);
+
+        /* Release RX buffers NB start at index 0 not current HW ptr */
+        if (rx_queue->buffer) {
+                for (i = 0; i <= rx_queue->efx->type->rxd_ring_mask; i++) {
+                        rx_buf = efx_rx_buffer(rx_queue, i);
+                        efx_fini_rx_buffer(rx_queue, rx_buf);
+                }
+        }
+
+        /* For a page that is part-way through splitting into RX buffers */
+        if (rx_queue->buf_page != NULL) {
+                pci_unmap_page(rx_queue->efx->pci_dev, rx_queue->buf_dma_addr,
+                               RX_PAGE_SIZE(rx_queue->efx), PCI_DMA_FROMDEVICE);
+                __free_pages(rx_queue->buf_page,
+                             rx_queue->efx->rx_buffer_order);
+                rx_queue->buf_page = NULL;
+        }
+}
+
+void efx_remove_rx_queue(struct efx_rx_queue *rx_queue)
+{
+        EFX_LOG(rx_queue->efx, "destroying RX queue %d\n", rx_queue->queue);
+
+        falcon_remove_rx(rx_queue);
+
+        kfree(rx_queue->buffer);
+        rx_queue->buffer = NULL;
+        rx_queue->used = 0;
+}
+
+void efx_flush_lro(struct efx_channel *channel)
+{
+        lro_flush_all(&channel->lro_mgr);
+}
+
+
+module_param(rx_alloc_method, int, 0644);
+MODULE_PARM_DESC(rx_alloc_method, "Allocation method used for RX buffers");
+
+module_param(rx_refill_threshold, uint, 0444);
+MODULE_PARM_DESC(rx_refill_threshold,
+                 "RX descriptor ring fast/slow fill threshold (%)");
+