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Subject[PATCH 6/6] tilegx network driver: initial support
This change adds support for the tilegx network driver based on the
GXIO IORPC support in the tilegx software stack, using the on-chip
mPIPE packet processing engine.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
---
drivers/net/ethernet/tile/Kconfig | 1 +
drivers/net/ethernet/tile/Makefile | 4 +-
drivers/net/ethernet/tile/tilegx.c | 2045 ++++++++++++++++++++++++++++++++++++
3 files changed, 2048 insertions(+), 2 deletions(-)
create mode 100644 drivers/net/ethernet/tile/tilegx.c
diff --git a/drivers/net/ethernet/tile/Kconfig b/drivers/net/ethernet/tile/Kconfig
index 2d9218f..9184b61 100644
--- a/drivers/net/ethernet/tile/Kconfig
+++ b/drivers/net/ethernet/tile/Kconfig
@@ -7,6 +7,7 @@ config TILE_NET
depends on TILE
default y
select CRC32
+ select TILE_GXIO_MPIPE if TILEGX
---help---
This is a standard Linux network device driver for the
on-chip Tilera Gigabit Ethernet and XAUI interfaces.
diff --git a/drivers/net/ethernet/tile/Makefile b/drivers/net/ethernet/tile/Makefile
index f634f14..0ef9eef 100644
--- a/drivers/net/ethernet/tile/Makefile
+++ b/drivers/net/ethernet/tile/Makefile
@@ -4,7 +4,7 @@

obj-$(CONFIG_TILE_NET) += tile_net.o
ifdef CONFIG_TILEGX
-tile_net-objs := tilegx.o mpipe.o iorpc_mpipe.o dma_queue.o
+tile_net-y := tilegx.o
else
-tile_net-objs := tilepro.o
+tile_net-y := tilepro.o
endif
diff --git a/drivers/net/ethernet/tile/tilegx.c b/drivers/net/ethernet/tile/tilegx.c
new file mode 100644
index 0000000..cca63e8
--- /dev/null
+++ b/drivers/net/ethernet/tile/tilegx.c
@@ -0,0 +1,2045 @@
+/*
+ * Copyright 2011 Tilera Corporation. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/moduleparam.h>
+#include <linux/sched.h>
+#include <linux/kernel.h> /* printk() */
+#include <linux/slab.h> /* kmalloc() */
+#include <linux/errno.h> /* error codes */
+#include <linux/types.h> /* size_t */
+#include <linux/interrupt.h>
+#include <linux/in.h>
+#include <linux/irq.h>
+#include <linux/netdevice.h> /* struct device, and other headers */
+#include <linux/etherdevice.h> /* eth_type_trans */
+#include <linux/skbuff.h>
+#include <linux/ioctl.h>
+#include <linux/cdev.h>
+#include <linux/hugetlb.h>
+#include <linux/in6.h>
+#include <linux/timer.h>
+#include <linux/io.h>
+#include <linux/ctype.h>
+#include <asm/checksum.h>
+#include <asm/homecache.h>
+
+#include <gxio/mpipe.h>
+
+/* For TSO */
+#include <linux/ip.h>
+#include <linux/tcp.h>
+
+
+#include <arch/sim.h>
+
+
+/* #define USE_SIM_PRINTF */
+
+#ifdef USE_SIM_PRINTF
+
+static __attribute__((unused, format (printf, 1, 2))) void
+sim_printf(const char *format, ...)
+{
+ char *str;
+ char buf[1024];
+
+ va_list args;
+ va_start(args, format);
+ (void)vsnprintf(buf, sizeof(buf), format, args);
+ va_end(args);
+
+ /* NOTE: Copied from "sim_print()". */
+ for (str = buf; *str != '\0'; str++) {
+ __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_PUTC |
+ (*str << _SIM_CONTROL_OPERATOR_BITS));
+ }
+ __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_PUTC |
+ (SIM_PUTC_FLUSH_BINARY << _SIM_CONTROL_OPERATOR_BITS));
+}
+
+
+/* HACK: Allow use of "sim_printf()" instead of "printk()". */
+#define printk sim_printf
+
+#endif
+
+
+/* First, "tile_net_init_module()" initializes each network cpu to
+ * handle incoming packets, and initializes all the network devices.
+ *
+ * Then, "ifconfig DEVICE up" calls "tile_net_open()", which will
+ * turn on packet processing, if needed.
+ *
+ * If "ifconfig DEVICE down" is called, it uses "tile_net_stop()" to
+ * stop egress, and possibly turn off packet processing.
+ *
+ * We start out with the ingress IRQ enabled on each CPU. When it
+ * fires, it is automatically disabled, and we call "napi_schedule()".
+ * This will cause "tile_net_poll()" to be called, which will pull
+ * packets from the netio queue, filtering them out, or passing them
+ * to "netif_receive_skb()". If our budget is exhausted, we will
+ * return, knowing we will be called again later. Otherwise, we
+ * reenable the ingress IRQ, and call "napi_complete()".
+ *
+ *
+ * NOTE: Failing to free completions for an arbitrarily long time
+ * (which is defined to be illegal) does in fact cause bizarre problems.
+ *
+ * NOTE: The egress code can be interrupted by the interrupt handler.
+ */
+
+
+/* HACK: Define to support GSO.
+ * ISSUE: This may actually hurt performance of the TCP blaster.
+ */
+#undef TILE_NET_GSO
+
+/* HACK: Define to support TSO. */
+#define TILE_NET_TSO
+
+/* Use 3000 to enable the Linux Traffic Control (QoS) layer, else 0. */
+#define TILE_NET_TX_QUEUE_LEN 0
+
+/* Define to dump packets (prints out the whole packet on tx and rx). */
+#undef TILE_NET_DUMP_PACKETS
+
+/* Define to use "round robin" distribution. */
+#undef TILE_NET_ROUND_ROBIN
+
+/* Default transmit lockup timeout period, in jiffies. */
+#define TILE_NET_TIMEOUT (5 * HZ)
+
+/* The number of distinct channels. */
+#define TILE_NET_CHANNELS (MPIPE_NUM_SGMII_MACS + MPIPE_NUM_LOOPBACK_CHANNELS)
+
+/* The max number of distinct devices ("xgbe" shares the "gbe" channels). */
+#define TILE_NET_DEVS (TILE_NET_CHANNELS + MPIPE_NUM_XAUI_MACS)
+
+/* Maximum number of idescs to handle per "poll". */
+#define TILE_NET_BATCH 128
+
+/* Maximum number of packets to handle per "poll". */
+#define TILE_NET_WEIGHT 64
+
+/* Number of entries in each iqueue. */
+#define IQUEUE_ENTRIES 512
+
+/* Number of entries in each equeue. */
+#define EQUEUE_ENTRIES 2048
+
+/* Total header bytes per equeue slot. Must be big enough for 2 bytes
+ * of NET_IP_ALIGN alignment, plus 14 bytes (?) of L2 header, plus up to
+ * 60 bytes of actual TCP header. We round up to align to cache lines.
+ */
+#define HEADER_BYTES 128
+
+/* Maximum completions per cpu per device (must be a power of two).
+ * ISSUE: What is the right number here?
+ */
+#define TILE_NET_MAX_COMPS 64
+
+
+#define ROUND_UP(n, align) (((n) + (align) - 1) & -(align))
+
+
+#define MAX_FRAGS (65536 / PAGE_SIZE + 2 + 1)
+
+
+MODULE_AUTHOR("Tilera");
+MODULE_LICENSE("GPL");
+
+
+
+/* A "packet fragment" (a chunk of memory). */
+struct frag {
+ void *buf;
+ size_t length;
+};
+
+
+/* Statistics counters for a specific cpu and device. */
+struct tile_net_stats_t {
+ u32 rx_packets;
+ u32 rx_bytes;
+ u32 tx_packets;
+ u32 tx_bytes;
+};
+
+
+/* A single completion. */
+struct tile_net_comp {
+ /* The "complete_count" when the completion will be complete. */
+ s64 when;
+ /* The buffer to be freed when the completion is complete. */
+ struct sk_buff *skb;
+};
+
+
+/* The completions for a given cpu and device. */
+struct tile_net_comps {
+ /* The completions. */
+ struct tile_net_comp comp_queue[TILE_NET_MAX_COMPS];
+ /* The number of completions used. */
+ unsigned long comp_next;
+ /* The number of completions freed. */
+ unsigned long comp_last;
+};
+
+
+/* Info for a specific cpu.
+ *
+ * ISSUE: Should "comps" be per channel instead of per dev?
+ */
+struct tile_net_info_t {
+ /* The NAPI struct. */
+ struct napi_struct napi;
+ /* Packet queue. */
+ gxio_mpipe_iqueue_t iqueue;
+ /* Our cpu. */
+ int my_cpu;
+ /* True if iqueue is valid. */
+ bool has_iqueue;
+ /* NAPI flags. */
+ bool napi_added;
+ bool napi_enabled;
+ /* Number of small sk_buffs which must still be provided. */
+ unsigned int num_needed_small_buffers;
+ /* Number of large sk_buffs which must still be provided. */
+ unsigned int num_needed_large_buffers;
+ /* A timer for handling egress completions. */
+ struct timer_list egress_timer;
+ /* True if "egress_timer" is scheduled. */
+ bool egress_timer_scheduled;
+ /* Comps for each device. */
+ struct tile_net_comps *comps_for_dev[TILE_NET_DEVS];
+ /* Stats for each device. */
+ struct tile_net_stats_t stats_for_dev[TILE_NET_DEVS];
+};
+
+
+/* Info for a specific device. */
+struct tile_net_priv {
+ /* Our network device. */
+ struct net_device *dev;
+ /* Our "devno". */
+ int devno;
+ /* The primary link. */
+ gxio_mpipe_link_t link;
+ /* The primary channel, if open, else -1. */
+ int channel;
+ /* The "loopify" egress link, if needed. */
+ gxio_mpipe_link_t loopify_link;
+ /* The "loopify" egress channel, if open, else -1. */
+ int loopify_channel;
+ /* Total stats. */
+ struct net_device_stats stats;
+ /* The (lazy) "equeue". */
+ gxio_mpipe_equeue_t *equeue;
+ /* The (lazy) headers for TSO. */
+ unsigned char *headers;
+};
+
+
+/* The actual devices. */
+static struct net_device *tile_net_devs[TILE_NET_DEVS];
+
+/* The device for a given channel. HACK: We use "32", not
+ * TILE_NET_CHANNELS, because it is fairly subtle that the 5 bit
+ * "idesc.channel" field never exceeds TILE_NET_CHANNELS.
+ */
+static struct net_device *tile_net_devs_for_channel[32];
+
+/* A mutex for "tile_net_devs_for_channel". */
+static struct mutex tile_net_devs_mutex;
+
+/* The per-cpu info. */
+static DEFINE_PER_CPU(struct tile_net_info_t, per_cpu_info);
+
+/* Access to "per_cpu_info". */
+static struct tile_net_info_t *infos[NR_CPUS];
+
+/* The "context" for all devices. */
+static gxio_mpipe_context_t context;
+
+/* The small/large "buffer stacks". */
+static int small_buffer_stack = -1;
+static int large_buffer_stack = -1;
+
+/* The buckets. */
+static int first_bucket = -1;
+static int num_buckets = 1;
+
+/* The ingress irq. */
+static int ingress_irq = -1;
+
+
+/* True if "network_cpus" was specified. */
+static bool network_cpus_used;
+
+/* The actual cpus in "network_cpus". */
+static struct cpumask network_cpus_map;
+
+
+/* If "loopify=LINK" was specified, this is "LINK". */
+static char loopify_link_name[16];
+
+
+
+#ifdef TILE_NET_DUMP_PACKETS
+/* Dump a packet. */
+static void dump_packet(unsigned char *data, unsigned long length, char *s)
+{
+ unsigned long i;
+ static unsigned int count;
+ char buf[128];
+
+ pr_info("Dumping %s packet of 0x%lx bytes at %p [%d]\n",
+ s, length, data, count++);
+
+ pr_info("\n");
+
+ for (i = 0; i < length; i++) {
+ if ((i & 0xf) == 0)
+ sprintf(buf, "%8.8lx:", i);
+ sprintf(buf + strlen(buf), " %02x", data[i]);
+ if ((i & 0xf) == 0xf || i == length - 1)
+ pr_info("%s\n", buf);
+ }
+
+ pr_info("\n");
+}
+#endif
+
+
+/* Convert a "buffer ptr" into a "buffer cpa". */
+static inline void *buf_to_cpa(void *buf)
+{
+ return (void *)__pa(buf);
+}
+
+
+/* Convert a "buffer cpa" into a "buffer ptr". */
+static inline void *cpa_to_buf(void *cpa)
+{
+ return (void *)__va(cpa);
+}
+
+
+
+/* Allocate and push a buffer. */
+static bool tile_net_provide_buffer(bool small)
+{
+ int stack = small ? small_buffer_stack : large_buffer_stack;
+
+ /* Buffers must be aligned. */
+ const unsigned long align = 128;
+
+ /* Note that "dev_alloc_skb()" adds NET_SKB_PAD more bytes,
+ * and also "reserves" that many bytes.
+ */
+ int len = sizeof(struct sk_buff **) + align + (small ? 128 : 1664);
+
+ /* Allocate (or fail). */
+ struct sk_buff *skb = dev_alloc_skb(len);
+ if (skb == NULL)
+ return false;
+
+ /* Make room for a back-pointer to 'skb'. */
+ skb_reserve(skb, sizeof(struct sk_buff **));
+
+ /* Make sure we are aligned. */
+ skb_reserve(skb, -(long)skb->data & (align - 1));
+
+ /* Save a back-pointer to 'skb'. */
+ *(struct sk_buff **)(skb->data - sizeof(struct sk_buff **)) = skb;
+
+ /* Make sure "skb" and the back-pointer have been flushed. */
+ __insn_mf();
+
+ gxio_mpipe_push_buffer(&context, stack, buf_to_cpa(skb->data));
+
+ return true;
+}
+
+
+/* Provide linux buffers to mPIPE. */
+static void tile_net_provide_needed_buffers(struct tile_net_info_t *info)
+{
+ while (info->num_needed_small_buffers != 0) {
+ if (!tile_net_provide_buffer(true))
+ goto oops;
+ info->num_needed_small_buffers--;
+ }
+
+ while (info->num_needed_large_buffers != 0) {
+ if (!tile_net_provide_buffer(false))
+ goto oops;
+ info->num_needed_large_buffers--;
+ }
+
+ return;
+
+oops:
+
+ /* Add a description to the page allocation failure dump. */
+ pr_notice("Tile %d still needs some buffers\n", info->my_cpu);
+}
+
+
+/* Handle a packet. Return true if "processed", false if "filtered". */
+static bool tile_net_handle_packet(struct tile_net_info_t *info,
+ gxio_mpipe_idesc_t *idesc)
+{
+ /* NOTE: This can be NULL during shutdown. */
+ struct net_device *dev = tile_net_devs_for_channel[idesc->channel];
+
+ void *va;
+
+ uint8_t l2_offset = gxio_mpipe_idesc_get_l2_offset(idesc);
+
+ void *buf;
+ unsigned long len;
+
+ int filter = 0;
+
+ /* Drop packets for which no buffer was available.
+ * NOTE: This happens under heavy load.
+ */
+ if (idesc->be) {
+ gxio_mpipe_iqueue_consume(&info->iqueue, idesc);
+ if (net_ratelimit())
+ pr_info("Dropping packet (insufficient buffers).\n");
+ return false;
+ }
+
+ /* Get the raw buffer VA. */
+ va = cpa_to_buf(gxio_mpipe_idesc_get_va(idesc));
+
+ /* Get the actual packet start/length. */
+ buf = va + l2_offset;
+ len = gxio_mpipe_idesc_get_l2_length(idesc);
+
+ /* Point "va" at the raw buffer. */
+ va -= NET_IP_ALIGN;
+
+#ifdef TILE_NET_DUMP_PACKETS
+ dump_packet(buf, len, "rx");
+#endif /* TILE_NET_DUMP_PACKETS */
+
+ if (dev != NULL) {
+ /* ISSUE: Is this needed? */
+ dev->last_rx = jiffies;
+ }
+
+ if (dev == NULL || !(dev->flags & IFF_UP)) {
+ /* Filter packets received before we're up. */
+ filter = 1;
+ } else if (!(dev->flags & IFF_PROMISC)) {
+ /* ISSUE: "eth_type_trans()" implies that "IFF_PROMISC"
+ * is set for "all silly devices", however, it appears
+ * to NOT be set for us, so this code here DOES run.
+ * FIXME: The classifier will soon detect "multicast".
+ */
+ if (!is_multicast_ether_addr(buf)) {
+ /* Filter packets not for our address. */
+ const u8 *mine = dev->dev_addr;
+ filter = compare_ether_addr(mine, buf);
+ }
+ }
+
+ if (filter) {
+
+ /* ISSUE: Update "drop" statistics? */
+
+ gxio_mpipe_iqueue_drop(&info->iqueue, idesc);
+
+ } else {
+
+ struct tile_net_priv *priv = netdev_priv(dev);
+ struct tile_net_stats_t *stats =
+ &info->stats_for_dev[priv->devno];
+
+ /* Acquire the associated "skb". */
+ struct sk_buff **skb_ptr = va - sizeof(*skb_ptr);
+ struct sk_buff *skb = *skb_ptr;
+
+ /* Paranoia. */
+ if (skb->data != va)
+ panic("Corrupt linux buffer! "
+ "buf=%p, skb=%p, skb->data=%p\n",
+ buf, skb, skb->data);
+
+ /* Skip headroom, and any custom header. */
+ skb_reserve(skb, NET_IP_ALIGN + l2_offset);
+
+ /* Encode the actual packet length. */
+ skb_put(skb, len);
+
+ /* NOTE: This call also sets "skb->dev = dev".
+ * ISSUE: The classifier provides us with "eth_type"
+ * (aka "eth->h_proto"), which is basically the value
+ * returned by "eth_type_trans()".
+ * Note that "eth_type_trans()" computes "skb->pkt_type",
+ * which would be useful for the "filter" check above,
+ * if we had a (modifiable) "skb" to work with.
+ */
+ skb->protocol = eth_type_trans(skb, dev);
+
+ /* Acknowledge "good" hardware checksums. */
+ if (idesc->cs && idesc->csum_seed_val == 0xFFFF)
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+ netif_receive_skb(skb);
+
+ /* Update stats. */
+ stats->rx_packets++;
+ stats->rx_bytes += len;
+
+ /* Need a new buffer. */
+ if (idesc->size == GXIO_MPIPE_BUFFER_SIZE_128)
+ info->num_needed_small_buffers++;
+ else
+ info->num_needed_large_buffers++;
+ }
+
+ gxio_mpipe_iqueue_consume(&info->iqueue, idesc);
+
+ return !filter;
+}
+
+
+/* Handle some packets for the current CPU.
+ *
+ * This function handles up to TILE_NET_BATCH idescs per call.
+ *
+ * ISSUE: Since we do not provide new buffers until this function is
+ * complete, we must initially provide enough buffers for each network
+ * cpu to fill its iqueue and also its batched idescs.
+ *
+ * ISSUE: The "rotting packet" race condition occurs if a packet
+ * arrives after the queue appears to be empty, and before the
+ * hypervisor interrupt is re-enabled.
+ */
+static int tile_net_poll(struct napi_struct *napi, int budget)
+{
+ struct tile_net_info_t *info = &__get_cpu_var(per_cpu_info);
+
+ unsigned int work = 0;
+
+ gxio_mpipe_idesc_t *idesc;
+ int i, n;
+
+ /* Process packets. */
+ while ((n = gxio_mpipe_iqueue_try_peek(&info->iqueue, &idesc)) > 0) {
+ for (i = 0; i < n; i++) {
+ if (i == TILE_NET_BATCH)
+ goto done;
+ if (tile_net_handle_packet(info, idesc + i)) {
+ if (++work >= budget)
+ goto done;
+ }
+ }
+ }
+
+ /* There are no packets left. */
+ napi_complete(&info->napi);
+
+ /* Re-enable hypervisor interrupts. */
+ gxio_mpipe_enable_notif_ring_interrupt(&context, info->iqueue.ring);
+
+ /* HACK: Avoid the "rotting packet" problem. */
+ if (gxio_mpipe_iqueue_try_peek(&info->iqueue, &idesc) > 0)
+ napi_schedule(&info->napi);
+
+ /* ISSUE: Handle completions? */
+
+done:
+
+ tile_net_provide_needed_buffers(info);
+
+ return work;
+}
+
+
+/* Handle an ingress interrupt on the current cpu. */
+static irqreturn_t tile_net_handle_ingress_irq(int irq, void *unused)
+{
+ struct tile_net_info_t *info = &__get_cpu_var(per_cpu_info);
+ napi_schedule(&info->napi);
+ return IRQ_HANDLED;
+}
+
+
+/* Free some completions. This must be called with interrupts blocked. */
+static void tile_net_free_comps(struct net_device *dev,
+ struct tile_net_comps *comps,
+ int limit, bool force_update)
+{
+ struct tile_net_priv *priv = netdev_priv(dev);
+
+ gxio_mpipe_equeue_t *equeue = priv->equeue;
+
+ int n = 0;
+ while (comps->comp_last < comps->comp_next) {
+ unsigned int cid = comps->comp_last % TILE_NET_MAX_COMPS;
+ struct tile_net_comp *comp = &comps->comp_queue[cid];
+ if (!gxio_mpipe_equeue_is_complete(equeue, comp->when,
+ force_update || n == 0))
+ return;
+ dev_kfree_skb_irq(comp->skb);
+ comps->comp_last++;
+ if (++n == limit)
+ return;
+ }
+}
+
+
+/* Make sure the egress timer is scheduled.
+ *
+ * Note that we use "schedule if not scheduled" logic instead of the more
+ * obvious "reschedule" logic, because "reschedule" is fairly expensive.
+ */
+static void tile_net_schedule_egress_timer(struct tile_net_info_t *info)
+{
+ if (!info->egress_timer_scheduled) {
+ mod_timer_pinned(&info->egress_timer, jiffies + 1);
+ info->egress_timer_scheduled = true;
+ }
+}
+
+
+/* The "function" for "info->egress_timer".
+ *
+ * This timer will reschedule itself as long as there are any pending
+ * completions expected for this tile.
+ */
+static void tile_net_handle_egress_timer(unsigned long arg)
+{
+ struct tile_net_info_t *info = (struct tile_net_info_t *)arg;
+
+ unsigned int k;
+
+ bool pending = false;
+
+ unsigned long irqflags;
+
+ local_irq_save(irqflags);
+
+ /* The timer is no longer scheduled. */
+ info->egress_timer_scheduled = false;
+
+ /* Free all possible comps for this tile. */
+ for (k = 0; k < TILE_NET_DEVS; k++) {
+ struct tile_net_comps *comps = info->comps_for_dev[k];
+ if (comps->comp_last >= comps->comp_next)
+ continue;
+ tile_net_free_comps(tile_net_devs[k], comps, -1, true);
+ pending = pending || (comps->comp_last < comps->comp_next);
+ }
+
+ /* Reschedule timer if needed. */
+ if (pending)
+ tile_net_schedule_egress_timer(info);
+
+ local_irq_restore(irqflags);
+}
+
+
+/* Prepare each CPU. */
+static void tile_net_prepare_cpu(void *unused)
+{
+ struct tile_net_info_t *info = &__get_cpu_var(per_cpu_info);
+
+ int my_cpu = smp_processor_id();
+
+ info->has_iqueue = false;
+
+ info->my_cpu = my_cpu;
+
+ /* Initialize the egress timer. */
+ init_timer(&info->egress_timer);
+ info->egress_timer.data = (long)info;
+ info->egress_timer.function = tile_net_handle_egress_timer;
+
+ infos[my_cpu] = info;
+}
+
+
+/* Helper function for "tile_net_update()". */
+static void tile_net_update_cpu(void *count_ptr)
+{
+ long count = *(long *)count_ptr;
+
+ struct tile_net_info_t *info = &__get_cpu_var(per_cpu_info);
+
+ if (info->has_iqueue) {
+ if (count != 0) {
+ if (!info->napi_added) {
+ /* FIXME: HACK: We use one of the devices.
+ * ISSUE: We never call "netif_napi_del()".
+ */
+ netif_napi_add(tile_net_devs[0], &info->napi,
+ tile_net_poll, TILE_NET_WEIGHT);
+ info->napi_added = true;
+ }
+ if (!info->napi_enabled) {
+ napi_enable(&info->napi);
+ info->napi_enabled = true;
+ }
+ enable_percpu_irq(ingress_irq, 0);
+ } else {
+ disable_percpu_irq(ingress_irq);
+ if (info->napi_enabled) {
+ napi_disable(&info->napi);
+ info->napi_enabled = false;
+ }
+ /* FIXME: Drain the iqueue. */
+ }
+ }
+}
+
+
+/* Helper function for tile_net_open() and tile_net_stop(). */
+static int tile_net_update(void)
+{
+ int channel;
+ long count = 0;
+ int cpu;
+
+ /* HACK: This is too big for the linux stack. */
+ static gxio_mpipe_rules_t rules;
+
+ gxio_mpipe_rules_init(&rules, &context);
+
+ /* TODO: Add support for "dmac" splitting? */
+ for (channel = 0; channel < TILE_NET_DEVS; channel++) {
+ if (tile_net_devs_for_channel[channel] == NULL)
+ continue;
+ if (count++ == 0) {
+ gxio_mpipe_rules_begin(&rules, first_bucket,
+ num_buckets, NULL);
+ gxio_mpipe_rules_set_headroom(&rules, NET_IP_ALIGN);
+ }
+ gxio_mpipe_rules_add_channel(&rules, channel);
+ }
+
+ /* NOTE: This can happen if there is no classifier.
+ * ISSUE: Can anything else cause it to happen?
+ */
+ if (gxio_mpipe_rules_commit(&rules) != 0) {
+ pr_warning("Failed to update classifier rules!\n");
+ return -EIO;
+ }
+
+ /* Update all cpus, sequentially (to protect "netif_napi_add()"). */
+ for_each_online_cpu(cpu)
+ smp_call_function_single(cpu, tile_net_update_cpu, &count, 1);
+
+ /* HACK: Allow packets to flow. */
+ if (count != 0)
+ sim_enable_mpipe_links(0, -1);
+
+ return 0;
+}
+
+
+/* Helper function for "tile_net_init_cpus()". */
+static void tile_net_init_stacks(int network_cpus_count)
+{
+ int err;
+ int i;
+
+ gxio_mpipe_buffer_size_enum_t small_buf_size =
+ GXIO_MPIPE_BUFFER_SIZE_128;
+ gxio_mpipe_buffer_size_enum_t large_buf_size =
+ GXIO_MPIPE_BUFFER_SIZE_1664;
+
+ int num_buffers;
+
+ size_t stack_bytes;
+
+ pte_t pte = { 0 };
+
+ void *mem;
+
+ num_buffers =
+ network_cpus_count * (IQUEUE_ENTRIES + TILE_NET_BATCH);
+
+ /* Compute stack bytes, honoring the 64KB minimum alignment. */
+ stack_bytes = ROUND_UP(gxio_mpipe_calc_buffer_stack_bytes(num_buffers),
+ 64 * 1024);
+ if (stack_bytes > HPAGE_SIZE)
+ panic("Cannot allocate %d physically contiguous buffers.",
+ num_buffers);
+
+#if 0
+ sim_printf("Using %d buffers for %d network cpus.\n",
+ num_buffers, network_cpus_count);
+#endif
+
+ /* Allocate two buffer stacks. */
+ small_buffer_stack = gxio_mpipe_alloc_buffer_stacks(&context, 2, 0, 0);
+ if (small_buffer_stack < 0)
+ panic("Failure in 'gxio_mpipe_alloc_buffer_stacks()'");
+ large_buffer_stack = small_buffer_stack + 1;
+
+ /* Allocate the small memory stack. */
+ mem = alloc_pages_exact(stack_bytes, GFP_KERNEL);
+ if (mem == NULL)
+ panic("Could not allocate buffer memory!");
+ err = gxio_mpipe_init_buffer_stack(&context, small_buffer_stack,
+ small_buf_size,
+ mem, stack_bytes, 0);
+ if (err != 0)
+ panic("Error %d in 'gxio_mpipe_init_buffer_stack()'.", err);
+
+ /* Allocate the large buffer stack. */
+ mem = alloc_pages_exact(stack_bytes, GFP_KERNEL);
+ if (mem == NULL)
+ panic("Could not allocate buffer memory!");
+ err = gxio_mpipe_init_buffer_stack(&context, large_buffer_stack,
+ large_buf_size,
+ mem, stack_bytes, 0);
+ if (err != 0)
+ panic("Error %d in 'gxio_mpipe_init_buffer_stack()'.", err);
+
+ /* Pin all the client memory. */
+ pte = pte_set_home(pte, PAGE_HOME_HASH);
+ err = gxio_mpipe_register_client_memory(&context, small_buffer_stack,
+ pte, 0);
+ if (err != 0)
+ panic("Error %d in 'gxio_mpipe_register_buffer_memory()'.",
+ err);
+ err = gxio_mpipe_register_client_memory(&context, large_buffer_stack,
+ pte, 0);
+ if (err != 0)
+ panic("Error %d in 'gxio_mpipe_register_buffer_memory()'.",
+ err);
+
+ /* Provide initial buffers. */
+ for (i = 0; i < num_buffers; i++) {
+ if (!tile_net_provide_buffer(true))
+ panic("Cannot provide initial buffers!");
+ }
+ for (i = 0; i < num_buffers; i++) {
+ if (!tile_net_provide_buffer(false))
+ panic("Cannot provide initial buffers!");
+ }
+}
+
+
+/* Actually initialize the mPIPE state. */
+static int tile_net_init_cpus(void)
+{
+ int network_cpus_count;
+
+ int ring;
+ int group;
+
+ int next_ring;
+
+ int cpu;
+
+ int i;
+
+#ifdef TILE_NET_ROUND_ROBIN
+ gxio_mpipe_bucket_mode_t mode = GXIO_MPIPE_BUCKET_ROUND_ROBIN;
+#else
+ /* Use random rebalancing. */
+ gxio_mpipe_bucket_mode_t mode = GXIO_MPIPE_BUCKET_STICKY_FLOW_LOCALITY;
+#endif
+
+ if (!hash_default) {
+ pr_warning("Networking requires hash_default!\n");
+ goto fail;
+ }
+
+ if (gxio_mpipe_init(&context, 0) != 0) {
+ pr_warning("Failed to initialize mPIPE!\n");
+ goto fail;
+ }
+
+ if (!network_cpus_used)
+ network_cpus_map = cpu_online_map;
+
+#ifdef CONFIG_DATAPLANE
+ /* Remove dataplane cpus. */
+ cpus_andnot(network_cpus_map, network_cpus_map, dataplane_map);
+#endif
+
+ network_cpus_count = cpus_weight(network_cpus_map);
+
+ /* ISSUE: Handle failures more gracefully. */
+ tile_net_init_stacks(network_cpus_count);
+
+ /* Allocate one NotifRing for each network cpu. */
+ ring = gxio_mpipe_alloc_notif_rings(&context, network_cpus_count,
+ 0, 0);
+ if (ring < 0) {
+ pr_warning("Failed to allocate notif rings.\n");
+ goto fail;
+ }
+
+ /* ISSUE: Handle failures below more cleanly. */
+
+ /* Init NotifRings. */
+ next_ring = ring;
+
+ for_each_online_cpu(cpu) {
+
+ size_t notif_ring_size =
+ IQUEUE_ENTRIES * sizeof(gxio_mpipe_idesc_t);
+
+ int order;
+ struct page *page;
+ void *addr;
+
+ struct tile_net_info_t *info = infos[cpu];
+
+ size_t comps_size =
+ TILE_NET_DEVS * sizeof(struct tile_net_comps);
+
+ /* Allocate the "comps". */
+ order = get_order(comps_size);
+ page = homecache_alloc_pages(GFP_KERNEL, order, cpu);
+ if (page == NULL)
+ panic("Failed to allocate comps memory.");
+ addr = pfn_to_kaddr(page_to_pfn(page));
+ /* ISSUE: Is this needed? */
+ memset(addr, 0, comps_size);
+ for (i = 0; i < TILE_NET_DEVS; i++)
+ info->comps_for_dev[i] =
+ addr + i * sizeof(struct tile_net_comps);
+
+ /* Only network cpus can receive packets. */
+ if (!cpu_isset(cpu, network_cpus_map))
+ continue;
+
+ /* Allocate the actual idescs array. */
+ order = get_order(notif_ring_size);
+ page = homecache_alloc_pages(GFP_KERNEL, order, cpu);
+ if (page == NULL)
+ panic("Failed to allocate iqueue memory.");
+ addr = pfn_to_kaddr(page_to_pfn(page));
+
+ if (gxio_mpipe_iqueue_init(&info->iqueue, &context, next_ring,
+ addr, notif_ring_size, 0) != 0)
+ panic("Failure in 'gxio_mpipe_iqueue_init()'.");
+
+ info->has_iqueue = true;
+
+ next_ring++;
+ }
+
+ /* Allocate one NotifGroup. */
+ group = gxio_mpipe_alloc_notif_groups(&context, 1, 0, 0);
+ if (group < 0)
+ panic("Failure in 'gxio_mpipe_alloc_notif_groups()'.");
+
+#ifndef TILE_NET_ROUND_ROBIN
+ if (network_cpus_count > 4)
+ num_buckets = 256;
+ else if (network_cpus_count > 1)
+ num_buckets = 16;
+#endif
+
+ /* Allocate some buckets. */
+ first_bucket = gxio_mpipe_alloc_buckets(&context, num_buckets, 0, 0);
+ if (first_bucket < 0)
+ panic("Failure in 'gxio_mpipe_alloc_buckets()'.");
+
+ /* Init group and buckets. */
+ if (gxio_mpipe_init_notif_group_and_buckets(&context, group, ring,
+ network_cpus_count,
+ first_bucket, num_buckets,
+ mode) != 0)
+ panic("Fail in 'gxio_mpipe_init_notif_group_and_buckets().");
+
+
+ /* Create an irq and register it. */
+ ingress_irq = create_irq();
+ if (ingress_irq < 0)
+ panic("Failed to create irq for ingress.");
+ tile_irq_activate(ingress_irq, TILE_IRQ_PERCPU);
+ BUG_ON(request_irq(ingress_irq, tile_net_handle_ingress_irq,
+ 0, NULL, NULL) != 0);
+
+ for_each_online_cpu(cpu) {
+
+ struct tile_net_info_t *info = infos[cpu];
+
+ int ring = info->iqueue.ring;
+
+ if (!info->has_iqueue)
+ continue;
+
+ gxio_mpipe_request_notif_ring_interrupt(&context,
+ cpu_x(cpu), cpu_y(cpu),
+ 1, ingress_irq, ring);
+ }
+
+ return 0;
+
+fail:
+ return -EIO;
+}
+
+
+/* Create persistent egress info for a given channel.
+ *
+ * Note that this may be shared between, say, "gbe0" and "xgbe0".
+ */
+static int tile_net_init_egress(struct tile_net_priv *priv)
+{
+ int channel =
+ ((priv->loopify_channel >= 0) ?
+ priv->loopify_channel : priv->channel);
+
+ size_t headers_order;
+ struct page *headers_page;
+ unsigned char* headers;
+
+ size_t edescs_size;
+ int edescs_order;
+ struct page *edescs_page;
+ gxio_mpipe_edesc_t* edescs;
+
+ int equeue_order;
+ struct page *equeue_page;
+ gxio_mpipe_equeue_t* equeue;
+ int edma;
+
+ /* Allocate memory for the "headers".
+ * ISSUE: Defer this until TSO is actually needed?
+ */
+ headers_order = get_order(EQUEUE_ENTRIES * HEADER_BYTES);
+ headers_page = alloc_pages(GFP_KERNEL, headers_order);
+ if (headers_page == NULL) {
+ pr_warning("Could not allocate memory for TSO headers.\n");
+ goto fail;
+ }
+ headers = pfn_to_kaddr(page_to_pfn(headers_page));
+
+ /* Allocate memory for the "edescs". */
+ edescs_size = EQUEUE_ENTRIES * sizeof(*edescs);
+ edescs_order = get_order(edescs_size);
+ edescs_page = alloc_pages(GFP_KERNEL, edescs_order);
+ if (edescs_page == NULL) {
+ pr_warning("Could not allocate memory for eDMA ring.\n");
+ goto fail_headers;
+ }
+ edescs = pfn_to_kaddr(page_to_pfn(edescs_page));
+
+ /* Allocate memory for the "equeue". */
+ equeue_order = get_order(sizeof(*equeue));
+ equeue_page = alloc_pages(GFP_KERNEL, equeue_order);
+ if (equeue_page == NULL) {
+ pr_warning("Could not allocate memory for equeue info.\n");
+ goto fail_edescs;
+ }
+ equeue = pfn_to_kaddr(page_to_pfn(equeue_page));
+
+ /* Allocate an edma ring. */
+ edma = gxio_mpipe_alloc_edma_rings(&context, 1, 0, 0);
+ if (edma < 0) {
+ pr_warning("Could not allocate edma ring.\n");
+ goto fail_equeue;
+ }
+
+ /* Initialize the equeue. This should not fail. */
+ if (gxio_mpipe_equeue_init(equeue, &context, edma, channel,
+ edescs, edescs_size, 0) != 0)
+ panic("Failure in 'gxio_mpipe_equeue_init()'.");
+
+ /* Done. */
+ priv->equeue = equeue;
+ priv->headers = headers;
+ return 0;
+
+fail_equeue:
+ __free_pages(equeue_page, equeue_order);
+
+fail_edescs:
+ __free_pages(edescs_page, edescs_order);
+
+fail_headers:
+ __free_pages(headers_page, headers_order);
+
+fail:
+ return -EIO;
+}
+
+
+/* Help the kernel activate the given network interface. */
+static int tile_net_open(struct net_device *dev)
+{
+ struct tile_net_priv *priv = netdev_priv(dev);
+
+ /* Determine if this is the "loopify" device. */
+ bool loopify = !strcmp(dev->name, loopify_link_name);
+
+ int result;
+
+ mutex_lock(&tile_net_devs_mutex);
+
+ if (ingress_irq < 0) {
+ result = tile_net_init_cpus();
+ if (result != 0)
+ goto fail;
+ }
+
+ if (priv->channel < 0) {
+ const char* ln = loopify ? "loop0" : dev->name;
+ if (gxio_mpipe_link_open(&priv->link, &context, ln, 0) < 0) {
+ netdev_err(dev, "Failed to open '%s'.\n", ln);
+ result = -EIO;
+ goto fail;
+ }
+ priv->channel = gxio_mpipe_link_channel(&priv->link);
+ BUG_ON(priv->channel < 0 || priv->channel >= 32);
+ }
+
+ if (loopify && priv->loopify_channel < 0) {
+ if (gxio_mpipe_link_open(&priv->loopify_link,
+ &context, "loop1", 0) < 0) {
+ netdev_err(dev, "Failed to open 'loop1'.\n");
+ result = -EIO;
+ goto fail;
+ }
+ priv->loopify_channel =
+ gxio_mpipe_link_channel(&priv->loopify_link);
+ BUG_ON(priv->loopify_channel < 0);
+ }
+
+ /* Initialize egress info (if needed). */
+ if (priv->equeue == NULL) {
+ result = tile_net_init_egress(priv);
+ if (result != 0)
+ goto fail;
+ }
+
+ tile_net_devs_for_channel[priv->channel] = dev;
+
+ result = tile_net_update();
+ if (result != 0)
+ goto fail_channel;
+
+ mutex_unlock(&tile_net_devs_mutex);
+
+ /* Start our transmit queue. */
+ netif_start_queue(dev);
+
+ netif_carrier_on(dev);
+
+ return 0;
+
+fail_channel:
+ tile_net_devs_for_channel[priv->channel] = NULL;
+
+fail:
+ if (priv->loopify_channel >= 0) {
+ if (gxio_mpipe_link_close(&priv->loopify_link) != 0)
+ pr_warning("Failed to close loopify link!\n");
+ else
+ priv->loopify_channel = -1;
+ }
+ if (priv->channel >= 0) {
+ if (gxio_mpipe_link_close(&priv->link) != 0)
+ pr_warning("Failed to close link!\n");
+ else
+ priv->channel = -1;
+ }
+
+ mutex_unlock(&tile_net_devs_mutex);
+ return result;
+}
+
+
+
+/* Help the kernel deactivate the given network interface. */
+static int tile_net_stop(struct net_device *dev)
+{
+ struct tile_net_priv *priv = netdev_priv(dev);
+
+ /* Stop our transmit queue. */
+ netif_stop_queue(dev);
+
+ mutex_lock(&tile_net_devs_mutex);
+
+ tile_net_devs_for_channel[priv->channel] = NULL;
+
+ (void)tile_net_update();
+
+ if (priv->loopify_channel >= 0) {
+ if (gxio_mpipe_link_close(&priv->loopify_link) != 0)
+ pr_warning("Failed to close loopify link!\n");
+ priv->loopify_channel = -1;
+ }
+
+ if (priv->channel >= 0) {
+ if (gxio_mpipe_link_close(&priv->link) != 0)
+ pr_warning("Failed to close link!\n");
+ priv->channel = -1;
+ }
+
+ mutex_unlock(&tile_net_devs_mutex);
+
+ return 0;
+}
+
+
+/* Determine the VA for a fragment. */
+static inline void *tile_net_frag_buf(skb_frag_t *f)
+{
+ unsigned long pfn = page_to_pfn(skb_frag_page(f));
+ return pfn_to_kaddr(pfn) + f->page_offset;
+}
+
+
+/* This function takes "skb", consisting of a header template and a
+ * (presumably) huge payload, and egresses it as one or more segments
+ * (aka packets), each consisting of a (possibly modified) copy of the
+ * header plus a piece of the payload, via "tcp segmentation offload".
+ *
+ * Usually, "data" will contain the header template, of size "sh_len",
+ * and "sh->frags" will contain "skb->data_len" bytes of payload, and
+ * there will be "sh->gso_segs" segments.
+ *
+ * Sometimes, if "sendfile()" requires copying, we will be called with
+ * "data" containing the header and payload, with "frags" being empty.
+ *
+ * Sometimes, for example when using NFS over TCP, a single segment can
+ * span 3 fragments. This requires special care below.
+ *
+ * See "emulate_large_send_offload()" for some reference code, which
+ * does not handle checksumming.
+ */
+static int tile_net_tx_tso(struct sk_buff *skb, struct net_device *dev)
+{
+ struct tile_net_priv *priv = netdev_priv(dev);
+
+ gxio_mpipe_equeue_t *equeue = priv->equeue;
+
+ struct tile_net_info_t *info = &__get_cpu_var(per_cpu_info);
+
+ struct tile_net_stats_t *stats;
+
+ unsigned int len = skb->len;
+ unsigned char *data = skb->data;
+
+ /* The ip header follows the ethernet header. */
+ struct iphdr *ih = ip_hdr(skb);
+ unsigned int ih_len = ih->ihl * 4;
+
+ /* Note that "nh == iph", by definition. */
+ unsigned char *nh = skb_network_header(skb);
+ unsigned int eh_len = nh - data;
+
+ /* The tcp header follows the ip header. */
+ struct tcphdr *th = (struct tcphdr *)(nh + ih_len);
+ unsigned int th_len = th->doff * 4;
+
+ /* The total number of header bytes. */
+ unsigned int sh_len = eh_len + ih_len + th_len;
+
+ /* Help compute "jh->check". */
+ unsigned int isum_hack =
+ ((0xFFFF - ih->check) +
+ (0xFFFF - ih->tot_len) +
+ (0xFFFF - ih->id));
+
+ /* Help compute "uh->check". */
+ unsigned int tsum_hack = th->check + (0xFFFF ^ htons(len));
+
+ struct skb_shared_info *sh = skb_shinfo(skb);
+
+ /* The maximum payload size. */
+ unsigned int gso_size = sh->gso_size;
+
+ /* The size of the initial segments (including header). */
+ unsigned int mtu = sh_len + gso_size;
+
+ /* The size of the final segment (including header). */
+ unsigned int mtu2 = len - ((sh->gso_segs - 1) * gso_size);
+
+ /* Track tx stats. */
+ unsigned int tx_packets = 0;
+ unsigned int tx_bytes = 0;
+
+ /* Which segment are we on. */
+ unsigned int segment;
+
+ /* Get the initial ip "id". */
+ u16 id = ntohs(ih->id);
+
+ /* Get the initial tcp "seq". */
+ u32 seq = ntohl(th->seq);
+
+ /* The id of the current fragment (or -1). */
+ long f_id;
+
+ /* The size of the current fragment (or -1). */
+ long f_size;
+
+ /* The bytes used from the current fragment (or -1). */
+ long f_used;
+
+ /* The size of the current piece of payload. */
+ long n;
+
+ /* Prepare checksum info. */
+ unsigned int csum_start = skb_checksum_start_offset(skb);
+
+ /* The header/payload edesc's. */
+ gxio_mpipe_edesc_t edesc_head = { { 0 } };
+ gxio_mpipe_edesc_t edesc_body = { { 0 } };
+
+ /* Total number of edescs needed. */
+ unsigned int num_edescs = 0;
+
+ unsigned long irqflags;
+
+ /* First reserved egress slot. */
+ s64 slot;
+
+ struct tile_net_comps *comps;
+
+ int cid;
+
+ /* Empty packets (etc) would cause trouble below. */
+ BUG_ON(skb->data_len == 0);
+ BUG_ON(sh->nr_frags == 0);
+ BUG_ON(sh->gso_segs == 0);
+
+ /* We assume the frags contain the entire payload. */
+ BUG_ON(skb_headlen(skb) != sh_len);
+ BUG_ON(len != sh_len + skb->data_len);
+
+ /* Implicitly verify "gso_segs" and "gso_size". */
+ BUG_ON(mtu2 > mtu);
+
+ /* We only have HEADER_BYTES for each header. */
+ BUG_ON(NET_IP_ALIGN + sh_len > HEADER_BYTES);
+
+ /* Paranoia. */
+ BUG_ON(skb->protocol != htons(ETH_P_IP));
+ BUG_ON(ih->protocol != IPPROTO_TCP);
+ BUG_ON(skb->ip_summed != CHECKSUM_PARTIAL);
+ BUG_ON(csum_start != eh_len + ih_len);
+
+ /* NOTE: ".hwb = 0", so ".size" is unused.
+ * NOTE: ".stack_idx" determines the TLB.
+ */
+
+ /* Prepare to egress the headers. */
+ edesc_head.csum = 1;
+ edesc_head.csum_start = csum_start;
+ edesc_head.csum_dest = csum_start + skb->csum_offset;
+ edesc_head.xfer_size = sh_len;
+ edesc_head.stack_idx = large_buffer_stack;
+
+ /* Prepare to egress the body. */
+ edesc_body.stack_idx = large_buffer_stack;
+
+ /* Reset. */
+ f_id = f_size = f_used = -1;
+
+ /* Determine how many edesc's are needed. */
+ for (segment = 0; segment < sh->gso_segs; segment++) {
+
+ /* Detect the final segment. */
+ bool final = (segment == sh->gso_segs - 1);
+
+ /* The segment size (including header). */
+ unsigned int s_len = final ? mtu2 : mtu;
+
+ /* The size of the payload. */
+ unsigned int p_len = s_len - sh_len;
+
+ /* The bytes used from the payload. */
+ unsigned int p_used = 0;
+
+ /* One edesc for the header. */
+ num_edescs++;
+
+ /* One edesc for each piece of the payload. */
+ while (p_used < p_len) {
+
+ /* Advance as needed. */
+ while (f_used >= f_size) {
+ f_id++;
+ f_size = sh->frags[f_id].size;
+ f_used = 0;
+ }
+
+ /* Use bytes from the current fragment. */
+ n = p_len - p_used;
+ if (n > f_size - f_used)
+ n = f_size - f_used;
+ f_used += n;
+ p_used += n;
+
+ num_edescs++;
+ }
+ }
+
+ /* Verify all fragments consumed. */
+ BUG_ON(f_id + 1 != sh->nr_frags);
+ BUG_ON(f_used != f_size);
+
+ local_irq_save(irqflags);
+
+ /* Reserve slots, or return NETDEV_TX_BUSY if "full". */
+ slot = gxio_mpipe_equeue_try_reserve(equeue, num_edescs);
+ if (slot < 0) {
+ if (net_ratelimit())
+ pr_info("Egress blocked on '%s'!\n", dev->name);
+ local_irq_restore(irqflags);
+ return NETDEV_TX_BUSY;
+ }
+
+ /* Reset. */
+ f_id = f_size = f_used = -1;
+
+ /* Prepare all the headers. */
+ for (segment = 0; segment < sh->gso_segs; segment++) {
+
+ /* Detect the final segment. */
+ bool final = (segment == sh->gso_segs - 1);
+
+ /* The segment size (including header). */
+ unsigned int s_len = final ? mtu2 : mtu;
+
+ /* The size of the payload. */
+ unsigned int p_len = s_len - sh_len;
+
+ /* The bytes used from the payload. */
+ unsigned int p_used = 0;
+
+ /* Access the header memory for this segment. */
+ unsigned int bn = slot % EQUEUE_ENTRIES;
+ unsigned char *buf =
+ priv->headers + bn * HEADER_BYTES + NET_IP_ALIGN;
+
+ /* The soon-to-be copied "ip" header. */
+ struct iphdr *jh = (struct iphdr *)(buf + eh_len);
+
+ /* The soon-to-be copied "tcp" header. */
+ struct tcphdr *uh = (struct tcphdr *)(buf + eh_len + ih_len);
+
+ unsigned int jsum, usum;
+
+ /* Copy the header. */
+ memcpy(buf, data, sh_len);
+
+ /* The packet size, not including ethernet header. */
+ jh->tot_len = htons(s_len - eh_len);
+
+ /* Update the ip "id". */
+ jh->id = htons(id);
+
+ /* Compute the "ip checksum". */
+ jsum = isum_hack + htons(s_len - eh_len) + htons(id);
+ jsum = __insn_v2sadu(jsum, 0);
+ jsum = __insn_v2sadu(jsum, 0);
+ jsum = (0xFFFF ^ jsum);
+ jh->check = jsum;
+
+ /* Update the tcp "seq". */
+ uh->seq = htonl(seq);
+
+ /* Update some flags. */
+ if (!final)
+ uh->fin = uh->psh = 0;
+
+ /* Compute the tcp pseudo-header checksum. */
+ usum = tsum_hack + htons(s_len);
+ usum = __insn_v2sadu(usum, 0);
+ usum = __insn_v2sadu(usum, 0);
+ uh->check = usum;
+
+ /* Skip past the header. */
+ slot++;
+
+ /* Skip past the payload. */
+ while (p_used < p_len) {
+
+ /* Advance as needed. */
+ while (f_used >= f_size) {
+ f_id++;
+ f_size = sh->frags[f_id].size;
+ f_used = 0;
+ }
+
+ /* Use bytes from the current fragment. */
+ n = p_len - p_used;
+ if (n > f_size - f_used)
+ n = f_size - f_used;
+ f_used += n;
+ p_used += n;
+
+ slot++;
+ }
+
+ id++;
+ seq += p_len;
+ }
+
+ /* Reset "slot". */
+ slot -= num_edescs;
+
+ /* Flush the headers. */
+ __insn_mf();
+
+ /* Reset. */
+ f_id = f_size = f_used = -1;
+
+ /* Egress all the edescs. */
+ for (segment = 0; segment < sh->gso_segs; segment++) {
+
+ /* Detect the final segment. */
+ bool final = (segment == sh->gso_segs - 1);
+
+ /* The segment size (including header). */
+ unsigned int s_len = final ? mtu2 : mtu;
+
+ /* The size of the payload. */
+ unsigned int p_len = s_len - sh_len;
+
+ /* The bytes used from the payload. */
+ unsigned int p_used = 0;
+
+ /* Access the header memory for this segment. */
+ unsigned int bn = slot % EQUEUE_ENTRIES;
+ unsigned char *buf =
+ priv->headers + bn * HEADER_BYTES + NET_IP_ALIGN;
+
+ void *va;
+
+ /* Egress the header. */
+ edesc_head.va = (ulong)buf_to_cpa(buf);
+ gxio_mpipe_equeue_put_at(equeue, edesc_head, slot);
+ slot++;
+
+ /* Egress the payload. */
+ while (p_used < p_len) {
+
+ /* Advance as needed. */
+ while (f_used >= f_size) {
+ f_id++;
+ f_size = sh->frags[f_id].size;
+ f_used = 0;
+ }
+
+ va = tile_net_frag_buf(&sh->frags[f_id]) + f_used;
+
+ /* Use bytes from the current fragment. */
+ n = p_len - p_used;
+ if (n > f_size - f_used)
+ n = f_size - f_used;
+ f_used += n;
+ p_used += n;
+
+ /* Egress a piece of the payload. */
+ edesc_body.va = (ulong)buf_to_cpa(va);
+ edesc_body.xfer_size = n;
+ edesc_body.bound = !(p_used < p_len);
+ gxio_mpipe_equeue_put_at(equeue, edesc_body, slot);
+ slot++;
+ }
+
+ tx_packets++;
+ tx_bytes += s_len;
+ }
+
+ comps = info->comps_for_dev[priv->devno];
+ cid = comps->comp_next % TILE_NET_MAX_COMPS;
+
+ /* Wait for a free completion entry.
+ * ISSUE: Is this the best logic?
+ * ISSUE: Can this cause undesirable "blocking"?
+ */
+ while (comps->comp_next - comps->comp_last >= TILE_NET_MAX_COMPS - 1)
+ tile_net_free_comps(dev, comps, 32, false);
+
+ /* Update the completions array. */
+ comps->comp_queue[cid].when = slot;
+ comps->comp_queue[cid].skb = skb;
+ comps->comp_next++;
+
+ /* Update stats. */
+ stats = &info->stats_for_dev[priv->devno];
+ stats->tx_packets += tx_packets;
+ stats->tx_bytes += tx_bytes;
+
+ local_irq_restore(irqflags);
+
+ /* Make sure the egress timer is scheduled. */
+ tile_net_schedule_egress_timer(info);
+
+ return NETDEV_TX_OK;
+}
+
+
+/* Analyze the body and frags for a transmit request. */
+static unsigned int tile_net_tx_frags(struct frag *frags,
+ struct sk_buff *skb,
+ void *b_data, unsigned int b_len)
+{
+ unsigned int i, n = 0;
+
+ struct skb_shared_info *sh = skb_shinfo(skb);
+
+ if (b_len != 0) {
+ frags[n].buf = b_data;
+ frags[n++].length = b_len;
+ }
+
+ for (i = 0; i < sh->nr_frags; i++) {
+ skb_frag_t *f = &sh->frags[i];
+ frags[n].buf = tile_net_frag_buf(f);
+ frags[n++].length = skb_frag_size(f);
+ }
+
+ return n;
+}
+
+
+/* Help the kernel transmit a packet. */
+static int tile_net_tx(struct sk_buff *skb, struct net_device *dev)
+{
+ struct tile_net_priv *priv = netdev_priv(dev);
+
+ gxio_mpipe_equeue_t *equeue = priv->equeue;
+
+ struct tile_net_info_t *info = &__get_cpu_var(per_cpu_info);
+
+ struct tile_net_stats_t *stats;
+
+ struct skb_shared_info *sh = skb_shinfo(skb);
+
+ unsigned int len = skb->len;
+ unsigned char *data = skb->data;
+
+ unsigned int num_frags;
+ struct frag frags[MAX_FRAGS];
+ gxio_mpipe_edesc_t edescs[MAX_FRAGS];
+
+ struct tile_net_comps *comps;
+
+ unsigned int i;
+
+ int cid;
+
+ s64 slot;
+
+ unsigned long irqflags;
+
+ /* Save the timestamp. */
+ dev->trans_start = jiffies;
+
+#ifdef TILE_NET_DUMP_PACKETS
+ /* ISSUE: Does not dump the "frags". */
+ dump_packet(data, skb_headlen(skb), "tx");
+#endif /* TILE_NET_DUMP_PACKETS */
+
+ if (sh->gso_size != 0)
+ return tile_net_tx_tso(skb, dev);
+
+ /* NOTE: This is usually 2, sometimes 3, for big writes. */
+ num_frags = tile_net_tx_frags(frags, skb, data, skb_headlen(skb));
+
+ /* Prepare the edescs. */
+ for (i = 0; i < num_frags; i++) {
+
+ /* NOTE: ".hwb = 0", so ".size" is unused.
+ * NOTE: ".stack_idx" determines the TLB.
+ */
+
+ gxio_mpipe_edesc_t edesc = { { 0 } };
+
+ /* Prepare the basic command. */
+ edesc.bound = (i == num_frags - 1);
+ edesc.xfer_size = frags[i].length;
+ edesc.va = (ulong)buf_to_cpa(frags[i].buf);
+ edesc.stack_idx = large_buffer_stack;
+
+ edescs[i] = edesc;
+ }
+
+ /* Add checksum info if needed. */
+ if (skb->ip_summed == CHECKSUM_PARTIAL) {
+ unsigned int csum_start = skb->csum_start - skb_headroom(skb);
+ edescs[0].csum = 1;
+ edescs[0].csum_start = csum_start;
+ edescs[0].csum_dest = csum_start + skb->csum_offset;
+ }
+
+ local_irq_save(irqflags);
+
+ /* Reserve slots, or return NETDEV_TX_BUSY if "full". */
+ slot = gxio_mpipe_equeue_try_reserve(equeue, num_frags);
+ if (slot < 0) {
+ if (net_ratelimit())
+ pr_info("Egress blocked on '%s'!\n", dev->name);
+ local_irq_restore(irqflags);
+ return NETDEV_TX_BUSY;
+ }
+
+ for (i = 0; i < num_frags; i++)
+ gxio_mpipe_equeue_put_at(equeue, edescs[i], slot + i);
+
+ comps = info->comps_for_dev[priv->devno];
+ cid = comps->comp_next % TILE_NET_MAX_COMPS;
+
+ /* Wait for a free completion entry.
+ * ISSUE: Is this the best logic?
+ */
+ while (comps->comp_next - comps->comp_last >= TILE_NET_MAX_COMPS - 1)
+ tile_net_free_comps(dev, comps, 32, false);
+
+ /* Update the completions array. */
+ comps->comp_queue[cid].when = slot + num_frags;
+ comps->comp_queue[cid].skb = skb;
+ comps->comp_next++;
+
+ /* HACK: Track "expanded" size for short packets (e.g. 42 < 60). */
+ stats = &info->stats_for_dev[priv->devno];
+ stats->tx_packets++;
+ stats->tx_bytes += ((len >= ETH_ZLEN) ? len : ETH_ZLEN);
+
+ local_irq_restore(irqflags);
+
+ /* Make sure the egress timer is scheduled. */
+ tile_net_schedule_egress_timer(info);
+
+ return NETDEV_TX_OK;
+}
+
+
+/* Deal with a transmit timeout. */
+static void tile_net_tx_timeout(struct net_device *dev)
+{
+ /* ISSUE: This doesn't seem useful for us. */
+ netif_wake_queue(dev);
+}
+
+
+/* Ioctl commands. */
+static int tile_net_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
+{
+ return -EOPNOTSUPP;
+}
+
+
+/* Get System Network Statistics.
+ *
+ * Returns the address of the device statistics structure.
+ */
+static struct net_device_stats *tile_net_get_stats(struct net_device *dev)
+{
+ struct tile_net_priv *priv = netdev_priv(dev);
+
+ int devno = priv->devno;
+
+ u32 rx_packets = 0;
+ u32 tx_packets = 0;
+ u32 rx_bytes = 0;
+ u32 tx_bytes = 0;
+ int i;
+
+ for_each_online_cpu(i) {
+ rx_packets += infos[i]->stats_for_dev[devno].rx_packets;
+ rx_bytes += infos[i]->stats_for_dev[devno].rx_bytes;
+ tx_packets += infos[i]->stats_for_dev[devno].tx_packets;
+ tx_bytes += infos[i]->stats_for_dev[devno].tx_bytes;
+ }
+
+ priv->stats.rx_packets = rx_packets;
+ priv->stats.rx_bytes = rx_bytes;
+ priv->stats.tx_packets = tx_packets;
+ priv->stats.tx_bytes = tx_bytes;
+
+ return &priv->stats;
+}
+
+
+/* Change the "mtu". */
+static int tile_net_change_mtu(struct net_device *dev, int new_mtu)
+{
+ /* Check ranges. */
+ if ((new_mtu < 68) || (new_mtu > 1500))
+ return -EINVAL;
+
+ /* Accept the value. */
+ dev->mtu = new_mtu;
+
+ return 0;
+}
+
+
+/* Change the Ethernet Address of the NIC.
+ *
+ * The hypervisor driver does not support changing MAC address. However,
+ * the hardware does not do anything with the MAC address, so the address
+ * which gets used on outgoing packets, and which is accepted on incoming
+ * packets, is completely up to us.
+ *
+ * Returns 0 on success, negative on failure.
+ */
+static int tile_net_set_mac_address(struct net_device *dev, void *p)
+{
+ struct sockaddr *addr = p;
+
+ if (!is_valid_ether_addr(addr->sa_data))
+ return -EINVAL;
+
+ memcpy(dev->dev_addr, addr->sa_data, dev->addr_len);
+
+ return 0;
+}
+
+
+#ifdef CONFIG_NET_POLL_CONTROLLER
+/* Polling 'interrupt' - used by things like netconsole to send skbs
+ * without having to re-enable interrupts. It's not called while
+ * the interrupt routine is executing.
+ */
+static void tile_net_netpoll(struct net_device *dev)
+{
+ disable_percpu_irq(ingress_irq);
+ tile_net_handle_ingress_irq(ingress_irq, NULL);
+ enable_percpu_irq(ingress_irq, 0);
+}
+#endif
+
+
+static const struct net_device_ops tile_net_ops = {
+ .ndo_open = tile_net_open,
+ .ndo_stop = tile_net_stop,
+ .ndo_start_xmit = tile_net_tx,
+ .ndo_do_ioctl = tile_net_ioctl,
+ .ndo_get_stats = tile_net_get_stats,
+ .ndo_change_mtu = tile_net_change_mtu,
+ .ndo_tx_timeout = tile_net_tx_timeout,
+ .ndo_set_mac_address = tile_net_set_mac_address,
+#ifdef CONFIG_NET_POLL_CONTROLLER
+ .ndo_poll_controller = tile_net_netpoll,
+#endif
+};
+
+/* The setup function.
+ *
+ * This uses ether_setup() to assign various fields in dev, including
+ * setting IFF_BROADCAST and IFF_MULTICAST, then sets some extra fields.
+ */
+static void tile_net_setup(struct net_device *dev)
+{
+ ether_setup(dev);
+
+ dev->netdev_ops = &tile_net_ops;
+ dev->watchdog_timeo = TILE_NET_TIMEOUT;
+
+ /* We want lockless xmit. */
+ dev->features |= NETIF_F_LLTX;
+
+ /* We support hardware tx checksums. */
+ dev->features |= NETIF_F_HW_CSUM;
+
+ /* We support scatter/gather. */
+ dev->features |= NETIF_F_SG;
+
+#ifdef TILE_NET_GSO
+ /* We support GSO. */
+ dev->features |= NETIF_F_GSO;
+#endif
+
+#ifdef TILE_NET_TSO
+ /* We support TSO. */
+ dev->features |= NETIF_F_TSO;
+#endif
+
+ dev->tx_queue_len = TILE_NET_TX_QUEUE_LEN;
+
+ dev->mtu = 1500;
+}
+
+
+/* Allocate the device structure, register the device, and obtain the
+ * MAC address from the hypervisor.
+ */
+static void tile_net_dev_init(const char *name, const uint8_t* mac)
+{
+ int ret;
+ int devno = 0;
+ int i;
+ int nz_addr = 0;
+ struct net_device *dev;
+ struct tile_net_priv *priv;
+
+ /* HACK: Ignore "loop" links. */
+ if (strncmp(name, "loop", 4) == 0)
+ return;
+
+ /* Find the next available devno. */
+ while (tile_net_devs[devno] != NULL)
+ devno++;
+
+ /* Allocate the device structure. This allocates "priv", calls
+ * tile_net_setup(), and saves "name". Normally, "name" is a
+ * template, instantiated by register_netdev(), but not for us.
+ */
+ dev = alloc_netdev(sizeof(*priv), name, tile_net_setup);
+ if (!dev) {
+ pr_err("alloc_netdev(%s) failed\n", name);
+ return;
+ }
+
+ priv = netdev_priv(dev);
+
+ /* Initialize "priv". */
+
+ memset(priv, 0, sizeof(*priv));
+
+ priv->dev = dev;
+ priv->devno = devno;
+
+ priv->channel = priv->loopify_channel = -1;
+
+ /* Save the device. */
+ tile_net_devs[devno] = dev;
+
+ /* Register the network device. */
+ ret = register_netdev(dev);
+ if (ret) {
+ netdev_err(dev, "register_netdev failed %d\n", ret);
+ free_netdev(dev);
+ tile_net_devs[devno] = NULL;
+ return;
+ }
+
+ /* Get the MAC address and set it in the device struct; this must
+ * be done before the device is opened. If the MAC is all zeroes,
+ * we use a random address, since we're probably on the simulator.
+ */
+ for (i = 0; i < 6; i++)
+ nz_addr |= mac[i];
+
+ if (nz_addr) {
+ memcpy(dev->dev_addr, mac, 6);
+ dev->addr_len = 6;
+ } else {
+ random_ether_addr(dev->dev_addr);
+ }
+}
+
+
+/* Module cleanup. */
+static void __exit tile_net_cleanup(void)
+{
+ int i;
+
+ for (i = 0; i < TILE_NET_DEVS; i++) {
+ struct net_device *dev = tile_net_devs[i];
+ if (dev != NULL) {
+ unregister_netdev(dev);
+ free_netdev(dev);
+ }
+ }
+}
+
+
+/* Module initialization. */
+static int __init tile_net_init_module(void)
+{
+ int i;
+ char name[GXIO_MPIPE_LINK_NAME_LEN];
+ uint8_t mac[6];
+
+ pr_info("Tilera Network Driver\n");
+
+ mutex_init(&tile_net_devs_mutex);
+
+ /* Initialize each CPU. */
+ on_each_cpu(tile_net_prepare_cpu, NULL, 1);
+
+ /* Find out what devices we have, and initialize them. */
+ for (i = 0; gxio_mpipe_link_enumerate_mac(i, name, mac) >= 0; i++)
+ tile_net_dev_init(name, mac);
+
+ return 0;
+}
+
+
+#ifndef MODULE
+/* The "network_cpus" boot argument specifies the cpus that are dedicated
+ * to handle ingress packets.
+ *
+ * The parameter should be in the form "network_cpus=m-n[,x-y]", where
+ * m, n, x, y are integer numbers that represent the cpus that can be
+ * neither a dedicated cpu nor a dataplane cpu.
+ */
+static int __init network_cpus_setup(char *str)
+{
+ int rc = cpulist_parse_crop(str, &network_cpus_map);
+ if (rc != 0) {
+ pr_warning("network_cpus=%s: malformed cpu list\n",
+ str);
+ } else {
+
+ /* Remove dedicated cpus. */
+ cpumask_and(&network_cpus_map, &network_cpus_map,
+ cpu_possible_mask);
+
+#ifdef CONFIG_DATAPLANE
+ /* Remove dataplane cpus. */
+ cpumask_andnot(&network_cpus_map, &network_cpus_map,
+ &dataplane_map);
+#endif
+
+ if (cpumask_empty(&network_cpus_map)) {
+ pr_warning("Ignoring network_cpus='%s'.\n", str);
+ } else {
+ char buf[1024];
+ cpulist_scnprintf(buf, sizeof(buf), &network_cpus_map);
+ pr_info("Linux network CPUs: %s\n", buf);
+ network_cpus_used = true;
+ }
+ }
+
+ return 0;
+}
+__setup("network_cpus=", network_cpus_setup);
+
+
+/* The "loopify=LINK" boot argument causes the named device to
+ * actually use "loop0" for ingress, and "loop1" for egress. This
+ * allows an app to sit between the actual link and linux, passing
+ * (some) packets along to linux, and forwarding (some) packets sent
+ * out by linux.
+ */
+static int __init loopify_setup(char *str)
+{
+ strncpy(loopify_link_name, str, sizeof(loopify_link_name) - 1);
+ return 0;
+}
+__setup("loopify=", loopify_setup);
+
+#endif
+
+
+module_init(tile_net_init_module);
+module_exit(tile_net_cleanup);
--
1.6.5.2


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