/* * 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 #include #include #include #include /* printk() */ #include /* kmalloc() */ #include /* error codes */ #include /* size_t */ #include #include #include /* struct device, and other headers */ #include /* eth_type_trans */ #include #include #include #include #include #include #include #include #include #include #include #include #include /* For TSO */ #include #include /* * First, "tile_net_init_module()" initializes all four "devices" which * can be used by linux. * * Then, "ifconfig DEVICE up" calls "tile_net_open()", which analyzes * the network cpus, then uses "tile_net_open_aux()" to initialize * LIPP/LEPP, and then uses "tile_net_open_inner()" to register all * the tiles, provide buffers to LIPP, allow ingress to start, and * turn on hypervisor interrupt handling (and NAPI) on all tiles. * * If registration fails due to the link being down, then "retry_work" * is used to keep calling "tile_net_open_inner()" until it succeeds. * * If "ifconfig DEVICE down" is called, it uses "tile_net_stop()" to * stop egress, drain the LIPP buffers, unregister all the tiles, stop * LIPP/LEPP, and wipe the LEPP queue. * * We start out with the ingress interrupt enabled on each CPU. When * this interrupt fires, we disable it, and 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 interrupt, and call "napi_complete()". * * HACK: Since disabling the ingress interrupt is not reliable, we * ignore the interrupt if the global "active" flag is false. * * * NOTE: The use of "native_driver" ensures that EPP exists, and that * we are using "LIPP" and "LEPP". * * NOTE: Failing to free completions for an arbitrarily long time * (which is defined to be illegal) does in fact cause bizarre * problems. The "egress_timer" helps prevent this from happening. */ /* HACK: Allow use of "jumbo" packets. */ /* This should be 1500 if "jumbo" is not set in LIPP. */ /* This should be at most 10226 (10240 - 14) if "jumbo" is set in LIPP. */ /* ISSUE: This has not been thoroughly tested (except at 1500). */ #define TILE_NET_MTU 1500 /* HACK: Define to support GSO. */ /* ISSUE: This may actually hurt performance of the TCP blaster. */ /* #define TILE_NET_GSO */ /* Define this to collapse "duplicate" acks. */ /* #define IGNORE_DUP_ACKS */ /* HACK: Define this to verify incoming packets. */ /* #define TILE_NET_VERIFY_INGRESS */ /* 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). */ /* #define TILE_NET_DUMP_PACKETS */ /* Define to enable debug spew (all PDEBUG's are enabled). */ /* #define TILE_NET_DEBUG */ /* Define to activate paranoia checks. */ /* #define TILE_NET_PARANOIA */ /* Default transmit lockup timeout period, in jiffies. */ #define TILE_NET_TIMEOUT (5 * HZ) /* Default retry interval for bringing up the NetIO interface, in jiffies. */ #define TILE_NET_RETRY_INTERVAL (5 * HZ) /* Number of ports (xgbe0, xgbe1, gbe0, gbe1). */ #define TILE_NET_DEVS 4 /* Paranoia. */ #if NET_IP_ALIGN != LIPP_PACKET_PADDING #error "NET_IP_ALIGN must match LIPP_PACKET_PADDING." #endif /* Debug print. */ #ifdef TILE_NET_DEBUG #define PDEBUG(fmt, args...) net_printk(fmt, ## args) #else #define PDEBUG(fmt, args...) #endif MODULE_AUTHOR("Tilera"); MODULE_LICENSE("GPL"); /* * Queue of incoming packets for a specific cpu and device. * * Includes a pointer to the "system" data, and the actual "user" data. */ struct tile_netio_queue { netio_queue_impl_t *__system_part; netio_queue_user_impl_t __user_part; }; /* * 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; }; /* * Info for a specific cpu and device. * * ISSUE: There is a "dev" pointer in "napi" as well. */ struct tile_net_cpu { /* The NAPI struct. */ struct napi_struct napi; /* Packet queue. */ struct tile_netio_queue queue; /* Statistics. */ struct tile_net_stats_t stats; /* True iff NAPI is enabled. */ bool napi_enabled; /* True if this tile has succcessfully registered with the IPP. */ bool registered; /* True if the link was down last time we tried to register. */ bool link_down; /* True if "egress_timer" is scheduled. */ bool egress_timer_scheduled; /* 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; }; /* * Info for a specific device. */ struct tile_net_priv { /* Our network device. */ struct net_device *dev; /* Pages making up the egress queue. */ struct page *eq_pages; /* Address of the actual egress queue. */ lepp_queue_t *eq; /* Protects "eq". */ spinlock_t eq_lock; /* The hypervisor handle for this interface. */ int hv_devhdl; /* The intr bit mask that IDs this device. */ u32 intr_id; /* True iff "tile_net_open_aux()" has succeeded. */ bool partly_opened; /* True iff the device is "active". */ bool active; /* Effective network cpus. */ struct cpumask network_cpus_map; /* Number of network cpus. */ int network_cpus_count; /* Credits per network cpu. */ int network_cpus_credits; /* Network stats. */ struct net_device_stats stats; /* For NetIO bringup retries. */ struct delayed_work retry_work; /* Quick access to per cpu data. */ struct tile_net_cpu *cpu[NR_CPUS]; }; /* Log2 of the number of small pages needed for the egress queue. */ #define EQ_ORDER get_order(sizeof(lepp_queue_t)) /* Size of the egress queue's pages. */ #define EQ_SIZE (1 << (PAGE_SHIFT + EQ_ORDER)) /* * The actual devices (xgbe0, xgbe1, gbe0, gbe1). */ static struct net_device *tile_net_devs[TILE_NET_DEVS]; /* * The "tile_net_cpu" structures for each device. */ static DEFINE_PER_CPU(struct tile_net_cpu, hv_xgbe0); static DEFINE_PER_CPU(struct tile_net_cpu, hv_xgbe1); static DEFINE_PER_CPU(struct tile_net_cpu, hv_gbe0); static DEFINE_PER_CPU(struct tile_net_cpu, hv_gbe1); /* * True if "network_cpus" was specified. */ static bool network_cpus_used; /* * The actual cpus in "network_cpus". */ static struct cpumask network_cpus_map; #ifdef TILE_NET_DEBUG /* * printk with extra stuff. * * We print the CPU we're running in brackets. */ static void net_printk(char *fmt, ...) { int i; int len; va_list args; static char buf[256]; len = sprintf(buf, "tile_net[%2.2d]: ", smp_processor_id()); va_start(args, fmt); i = vscnprintf(buf + len, sizeof(buf) - len - 1, fmt, args); va_end(args); buf[255] = '\0'; pr_notice(buf); } #endif #ifdef TILE_NET_DUMP_PACKETS /* * Dump a packet. */ static void dump_packet(unsigned char *data, unsigned long length, char *s) { int my_cpu = smp_processor_id(); unsigned long i; char buf[128]; static unsigned int count; pr_info("dump_packet(data %p, length 0x%lx s %s count 0x%x)\n", data, length, s, count++); pr_info("\n"); for (i = 0; i < length; i++) { if ((i & 0xf) == 0) sprintf(buf, "[%02d] %8.8lx:", my_cpu, i); sprintf(buf + strlen(buf), " %2.2x", data[i]); if ((i & 0xf) == 0xf || i == length - 1) { strcat(buf, "\n"); pr_info("%s", buf); } } } #endif /* * Provide support for the __netio_fastio1() swint * (see for how it is used). * * The fastio swint2 call may clobber all the caller-saved registers. * It rarely clobbers memory, but we allow for the possibility in * the signature just to be on the safe side. * * Also, gcc doesn't seem to allow an input operand to be * clobbered, so we fake it with dummy outputs. * * This function can't be static because of the way it is declared * in the netio header. */ inline int __netio_fastio1(u32 fastio_index, u32 arg0) { long result, clobber_r1, clobber_r10; asm volatile("swint2" : "=R00" (result), "=R01" (clobber_r1), "=R10" (clobber_r10) : "R10" (fastio_index), "R01" (arg0) : "memory", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r11", "r12", "r13", "r14", "r15", "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23", "r24", "r25", "r26", "r27", "r28", "r29"); return result; } /* * Provide a linux buffer to LIPP. */ static void tile_net_provide_linux_buffer(struct tile_net_cpu *info, void *va, bool small) { struct tile_netio_queue *queue = &info->queue; /* Convert "va" and "small" to "linux_buffer_t". */ unsigned int buffer = ((unsigned int)(__pa(va) >> 7) << 1) + small; __netio_fastio_free_buffer(queue->__user_part.__fastio_index, buffer); } /* * Provide a linux buffer for LIPP. * * Note that the ACTUAL allocation for each buffer is a "struct sk_buff", * plus a chunk of memory that includes not only the requested bytes, but * also NET_SKB_PAD bytes of initial padding, and a "struct skb_shared_info". * * Note that "struct skb_shared_info" is 88 bytes with 64K pages and * 268 bytes with 4K pages (since the frags[] array needs 18 entries). * * Without jumbo packets, the maximum packet size will be 1536 bytes, * and we use 2 bytes (NET_IP_ALIGN) of padding. ISSUE: If we told * the hardware to clip at 1518 bytes instead of 1536 bytes, then we * could save an entire cache line, but in practice, we don't need it. * * Since CPAs are 38 bits, and we can only encode the high 31 bits in * a "linux_buffer_t", the low 7 bits must be zero, and thus, we must * align the actual "va" mod 128. * * We assume that the underlying "head" will be aligned mod 64. Note * that in practice, we have seen "head" NOT aligned mod 128 even when * using 2048 byte allocations, which is surprising. * * If "head" WAS always aligned mod 128, we could change LIPP to * assume that the low SIX bits are zero, and the 7th bit is one, that * is, align the actual "va" mod 128 plus 64, which would be "free". * * For now, the actual "head" pointer points at NET_SKB_PAD bytes of * padding, plus 28 or 92 bytes of extra padding, plus the sk_buff * pointer, plus the NET_IP_ALIGN padding, plus 126 or 1536 bytes for * the actual packet, plus 62 bytes of empty padding, plus some * padding and the "struct skb_shared_info". * * With 64K pages, a large buffer thus needs 32+92+4+2+1536+62+88 * bytes, or 1816 bytes, which fits comfortably into 2048 bytes. * * With 64K pages, a small buffer thus needs 32+92+4+2+126+88 * bytes, or 344 bytes, which means we are wasting 64+ bytes, and * could presumably increase the size of small buffers. * * With 4K pages, a large buffer thus needs 32+92+4+2+1536+62+268 * bytes, or 1996 bytes, which fits comfortably into 2048 bytes. * * With 4K pages, a small buffer thus needs 32+92+4+2+126+268 * bytes, or 524 bytes, which is annoyingly wasteful. * * Maybe we should increase LIPP_SMALL_PACKET_SIZE to 192? * * ISSUE: Maybe we should increase "NET_SKB_PAD" to 64? */ static bool tile_net_provide_needed_buffer(struct tile_net_cpu *info, bool small) { #if TILE_NET_MTU <= 1536 /* Without "jumbo", 2 + 1536 should be sufficient. */ unsigned int large_size = NET_IP_ALIGN + 1536; #else /* ISSUE: This has not been tested. */ unsigned int large_size = NET_IP_ALIGN + TILE_NET_MTU + 100; #endif /* Avoid "false sharing" with last cache line. */ /* ISSUE: This is already done by "dev_alloc_skb()". */ unsigned int len = (((small ? LIPP_SMALL_PACKET_SIZE : large_size) + CHIP_L2_LINE_SIZE() - 1) & -CHIP_L2_LINE_SIZE()); unsigned int padding = 128 - NET_SKB_PAD; unsigned int align; struct sk_buff *skb; void *va; struct sk_buff **skb_ptr; /* Request 96 extra bytes for alignment purposes. */ skb = dev_alloc_skb(len + padding); if (skb == NULL) return false; /* Skip 32 or 96 bytes to align "data" mod 128. */ align = -(long)skb->data & (128 - 1); BUG_ON(align > padding); skb_reserve(skb, align); /* This address is given to IPP. */ va = skb->data; /* Buffers must not span a huge page. */ BUG_ON(((((long)va & ~HPAGE_MASK) + len) & HPAGE_MASK) != 0); #ifdef TILE_NET_PARANOIA #if CHIP_HAS_CBOX_HOME_MAP() if (hash_default) { HV_PTE pte = *virt_to_pte(current->mm, (unsigned long)va); if (hv_pte_get_mode(pte) != HV_PTE_MODE_CACHE_HASH_L3) panic("Non-HFH ingress buffer! VA=%p Mode=%d PTE=%llx", va, hv_pte_get_mode(pte), hv_pte_val(pte)); } #endif #endif /* Invalidate the packet buffer. */ if (!hash_default) __inv_buffer(va, len); /* Skip two bytes to satisfy LIPP assumptions. */ /* Note that this aligns IP on a 16 byte boundary. */ /* ISSUE: Do this when the packet arrives? */ skb_reserve(skb, NET_IP_ALIGN); /* Save a back-pointer to 'skb'. */ skb_ptr = va - sizeof(*skb_ptr); *skb_ptr = skb; /* Make sure "skb_ptr" has been flushed. */ __insn_mf(); /* Provide the new buffer. */ tile_net_provide_linux_buffer(info, va, small); return true; } /* * Provide linux buffers for LIPP. */ static void tile_net_provide_needed_buffers(struct tile_net_cpu *info) { while (info->num_needed_small_buffers != 0) { if (!tile_net_provide_needed_buffer(info, true)) goto oops; info->num_needed_small_buffers--; } while (info->num_needed_large_buffers != 0) { if (!tile_net_provide_needed_buffer(info, false)) goto oops; info->num_needed_large_buffers--; } return; oops: /* Add a description to the page allocation failure dump. */ pr_notice("Could not provide a linux buffer to LIPP.\n"); } /* * Grab some LEPP completions, and store them in "comps", of size * "comps_size", and return the number of completions which were * stored, so the caller can free them. */ static unsigned int tile_net_lepp_grab_comps(lepp_queue_t *eq, struct sk_buff *comps[], unsigned int comps_size, unsigned int min_size) { unsigned int n = 0; unsigned int comp_head = eq->comp_head; unsigned int comp_busy = eq->comp_busy; while (comp_head != comp_busy && n < comps_size) { comps[n++] = eq->comps[comp_head]; LEPP_QINC(comp_head); } if (n < min_size) return 0; eq->comp_head = comp_head; return n; } /* * Free some comps, and return true iff there are still some pending. */ static bool tile_net_lepp_free_comps(struct net_device *dev, bool all) { struct tile_net_priv *priv = netdev_priv(dev); lepp_queue_t *eq = priv->eq; struct sk_buff *olds[64]; unsigned int wanted = 64; unsigned int i, n; bool pending; spin_lock(&priv->eq_lock); if (all) eq->comp_busy = eq->comp_tail; n = tile_net_lepp_grab_comps(eq, olds, wanted, 0); pending = (eq->comp_head != eq->comp_tail); spin_unlock(&priv->eq_lock); for (i = 0; i < n; i++) kfree_skb(olds[i]); return pending; } /* * 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_cpu *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 (on behalf of any tile). * * ISSUE: Realistically, will the timer ever stop scheduling itself? * * ISSUE: This timer is almost never actually needed, so just use a global * timer that can run on any tile. * * ISSUE: Maybe instead track number of expected completions, and free * only that many, resetting to zero if "pending" is ever false. */ static void tile_net_handle_egress_timer(unsigned long arg) { struct tile_net_cpu *info = (struct tile_net_cpu *)arg; struct net_device *dev = info->napi.dev; /* The timer is no longer scheduled. */ info->egress_timer_scheduled = false; /* Free comps, and reschedule timer if more are pending. */ if (tile_net_lepp_free_comps(dev, false)) tile_net_schedule_egress_timer(info); } #ifdef IGNORE_DUP_ACKS /* * Help detect "duplicate" ACKs. These are sequential packets (for a * given flow) which are exactly 66 bytes long, sharing everything but * ID=2@0x12, Hsum=2@0x18, Ack=4@0x2a, WinSize=2@0x30, Csum=2@0x32, * Tstamps=10@0x38. The ID's are +1, the Hsum's are -1, the Ack's are * +N, and the Tstamps are usually identical. * * NOTE: Apparently truly duplicate acks (with identical "ack" values), * should not be collapsed, as they are used for some kind of flow control. */ static bool is_dup_ack(char *s1, char *s2, unsigned int len) { int i; unsigned long long ignorable = 0; /* Identification. */ ignorable |= (1ULL << 0x12); ignorable |= (1ULL << 0x13); /* Header checksum. */ ignorable |= (1ULL << 0x18); ignorable |= (1ULL << 0x19); /* ACK. */ ignorable |= (1ULL << 0x2a); ignorable |= (1ULL << 0x2b); ignorable |= (1ULL << 0x2c); ignorable |= (1ULL << 0x2d); /* WinSize. */ ignorable |= (1ULL << 0x30); ignorable |= (1ULL << 0x31); /* Checksum. */ ignorable |= (1ULL << 0x32); ignorable |= (1ULL << 0x33); for (i = 0; i < len; i++, ignorable >>= 1) { if ((ignorable & 1) || (s1[i] == s2[i])) continue; #ifdef TILE_NET_DEBUG /* HACK: Mention non-timestamp diffs. */ if (i < 0x38 && i != 0x2f && net_ratelimit()) pr_info("Diff at 0x%x\n", i); #endif return false; } #ifdef TILE_NET_NO_SUPPRESS_DUP_ACKS /* HACK: Do not suppress truly duplicate ACKs. */ /* ISSUE: Is this actually necessary or helpful? */ if (s1[0x2a] == s2[0x2a] && s1[0x2b] == s2[0x2b] && s1[0x2c] == s2[0x2c] && s1[0x2d] == s2[0x2d]) { return false; } #endif return true; } #endif static void tile_net_discard_aux(struct tile_net_cpu *info, int index) { struct tile_netio_queue *queue = &info->queue; netio_queue_impl_t *qsp = queue->__system_part; netio_queue_user_impl_t *qup = &queue->__user_part; int index2_aux = index + sizeof(netio_pkt_t); int index2 = ((index2_aux == qsp->__packet_receive_queue.__last_packet_plus_one) ? 0 : index2_aux); netio_pkt_t *pkt = (netio_pkt_t *)((unsigned long) &qsp[1] + index); /* Extract the "linux_buffer_t". */ unsigned int buffer = pkt->__packet.word; /* Convert "linux_buffer_t" to "va". */ void *va = __va((phys_addr_t)(buffer >> 1) << 7); /* Acquire the associated "skb". */ struct sk_buff **skb_ptr = va - sizeof(*skb_ptr); struct sk_buff *skb = *skb_ptr; kfree_skb(skb); /* Consume this packet. */ qup->__packet_receive_read = index2; } /* * Like "tile_net_poll()", but just discard packets. */ static void tile_net_discard_packets(struct net_device *dev) { struct tile_net_priv *priv = netdev_priv(dev); int my_cpu = smp_processor_id(); struct tile_net_cpu *info = priv->cpu[my_cpu]; struct tile_netio_queue *queue = &info->queue; netio_queue_impl_t *qsp = queue->__system_part; netio_queue_user_impl_t *qup = &queue->__user_part; while (qup->__packet_receive_read != qsp->__packet_receive_queue.__packet_write) { int index = qup->__packet_receive_read; tile_net_discard_aux(info, index); } } /* * Handle the next packet. Return true if "processed", false if "filtered". */ static bool tile_net_poll_aux(struct tile_net_cpu *info, int index) { struct net_device *dev = info->napi.dev; struct tile_netio_queue *queue = &info->queue; netio_queue_impl_t *qsp = queue->__system_part; netio_queue_user_impl_t *qup = &queue->__user_part; struct tile_net_stats_t *stats = &info->stats; int filter; int index2_aux = index + sizeof(netio_pkt_t); int index2 = ((index2_aux == qsp->__packet_receive_queue.__last_packet_plus_one) ? 0 : index2_aux); netio_pkt_t *pkt = (netio_pkt_t *)((unsigned long) &qsp[1] + index); netio_pkt_metadata_t *metadata = NETIO_PKT_METADATA(pkt); /* Extract the packet size. FIXME: Shouldn't the second line */ /* get subtracted? Mostly moot, since it should be "zero". */ unsigned long len = (NETIO_PKT_CUSTOM_LENGTH(pkt) + NET_IP_ALIGN - NETIO_PACKET_PADDING); /* Extract the "linux_buffer_t". */ unsigned int buffer = pkt->__packet.word; /* Extract "small" (vs "large"). */ bool small = ((buffer & 1) != 0); /* Convert "linux_buffer_t" to "va". */ void *va = __va((phys_addr_t)(buffer >> 1) << 7); /* Extract the packet data pointer. */ /* Compare to "NETIO_PKT_CUSTOM_DATA(pkt)". */ unsigned char *buf = va + NET_IP_ALIGN; /* Invalidate the packet buffer. */ if (!hash_default) __inv_buffer(buf, len); /* ISSUE: Is this needed? */ dev->last_rx = jiffies; #ifdef TILE_NET_DUMP_PACKETS dump_packet(buf, len, "rx"); #endif /* TILE_NET_DUMP_PACKETS */ #ifdef TILE_NET_VERIFY_INGRESS if (!NETIO_PKT_L4_CSUM_CORRECT_M(metadata, pkt) && NETIO_PKT_L4_CSUM_CALCULATED_M(metadata, pkt)) { /* Bug 6624: Includes UDP packets with a "zero" checksum. */ pr_warning("Bad L4 checksum on %d byte packet.\n", len); } if (!NETIO_PKT_L3_CSUM_CORRECT_M(metadata, pkt) && NETIO_PKT_L3_CSUM_CALCULATED_M(metadata, pkt)) { dump_packet(buf, len, "rx"); panic("Bad L3 checksum."); } switch (NETIO_PKT_STATUS_M(metadata, pkt)) { case NETIO_PKT_STATUS_OVERSIZE: if (len >= 64) { dump_packet(buf, len, "rx"); panic("Unexpected OVERSIZE."); } break; case NETIO_PKT_STATUS_BAD: pr_warning("Unexpected BAD %ld byte packet.\n", len); } #endif filter = 0; /* ISSUE: Filter TCP packets with "bad" checksums? */ if (!(dev->flags & IFF_UP)) { /* Filter packets received before we're up. */ filter = 1; } else if (NETIO_PKT_STATUS_M(metadata, pkt) == NETIO_PKT_STATUS_BAD) { /* Filter "truncated" packets. */ filter = 1; } else if (!(dev->flags & IFF_PROMISC)) { /* FIXME: Implement HW multicast filter. */ 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? */ tile_net_provide_linux_buffer(info, va, small); } else { /* Acquire the associated "skb". */ struct sk_buff **skb_ptr = va - sizeof(*skb_ptr); struct sk_buff *skb = *skb_ptr; /* Paranoia. */ if (skb->data != buf) panic("Corrupt linux buffer from LIPP! " "VA=%p, skb=%p, skb->data=%p\n", va, skb, skb->data); /* Encode the actual packet length. */ skb_put(skb, len); /* NOTE: This call also sets "skb->dev = dev". */ skb->protocol = eth_type_trans(skb, dev); /* Avoid recomputing "good" TCP/UDP checksums. */ if (NETIO_PKT_L4_CSUM_CORRECT_M(metadata, pkt)) skb->ip_summed = CHECKSUM_UNNECESSARY; netif_receive_skb(skb); stats->rx_packets++; stats->rx_bytes += len; if (small) info->num_needed_small_buffers++; else info->num_needed_large_buffers++; } /* Return four credits after every fourth packet. */ if (--qup->__receive_credit_remaining == 0) { u32 interval = qup->__receive_credit_interval; qup->__receive_credit_remaining = interval; __netio_fastio_return_credits(qup->__fastio_index, interval); } /* Consume this packet. */ qup->__packet_receive_read = index2; return !filter; } /* * Handle some packets for the given device on the current CPU. * * If "tile_net_stop()" is called on some other tile while this * function is running, we will return, hopefully before that * other tile asks us to call "napi_disable()". * * The "rotting packet" race condition occurs if a packet arrives * during the extremely narrow window between the queue appearing to * be empty, and the ingress interrupt being re-enabled. This happens * a LOT under heavy network load. */ static int tile_net_poll(struct napi_struct *napi, int budget) { struct net_device *dev = napi->dev; struct tile_net_priv *priv = netdev_priv(dev); int my_cpu = smp_processor_id(); struct tile_net_cpu *info = priv->cpu[my_cpu]; struct tile_netio_queue *queue = &info->queue; netio_queue_impl_t *qsp = queue->__system_part; netio_queue_user_impl_t *qup = &queue->__user_part; unsigned int work = 0; while (priv->active) { int index = qup->__packet_receive_read; if (index == qsp->__packet_receive_queue.__packet_write) break; if (tile_net_poll_aux(info, index)) { if (++work >= budget) goto done; } } napi_complete(&info->napi); if (!priv->active) goto done; /* Re-enable the ingress interrupt. */ enable_percpu_irq(priv->intr_id); /* HACK: Avoid the "rotting packet" problem (see above). */ if (qup->__packet_receive_read != qsp->__packet_receive_queue.__packet_write) { /* ISSUE: Sometimes this returns zero, presumably */ /* because an interrupt was handled for this tile. */ (void)napi_reschedule(&info->napi); } done: if (priv->active) tile_net_provide_needed_buffers(info); return work; } /* * Handle an ingress interrupt for the given device on the current cpu. * * ISSUE: Sometimes this gets called after "disable_percpu_irq()" has * been called! This is probably due to "pending hypervisor downcalls". * * ISSUE: Is there any race condition between the "napi_schedule()" here * and the "napi_complete()" call above? */ static irqreturn_t tile_net_handle_ingress_interrupt(int irq, void *dev_ptr) { struct net_device *dev = (struct net_device *)dev_ptr; struct tile_net_priv *priv = netdev_priv(dev); int my_cpu = smp_processor_id(); struct tile_net_cpu *info = priv->cpu[my_cpu]; /* Disable the ingress interrupt. */ disable_percpu_irq(priv->intr_id); /* Ignore unwanted interrupts. */ if (!priv->active) return IRQ_HANDLED; /* ISSUE: Sometimes "info->napi_enabled" is false here. */ napi_schedule(&info->napi); return IRQ_HANDLED; } /* * One time initialization per interface. */ static int tile_net_open_aux(struct net_device *dev) { struct tile_net_priv *priv = netdev_priv(dev); int ret; int dummy; unsigned int epp_lotar; /* * Find out where EPP memory should be homed. */ ret = hv_dev_pread(priv->hv_devhdl, 0, (HV_VirtAddr)&epp_lotar, sizeof(epp_lotar), NETIO_EPP_SHM_OFF); if (ret < 0) { pr_err("could not read epp_shm_queue lotar.\n"); return -EIO; } /* * Home the page on the EPP. */ { int epp_home = hv_lotar_to_cpu(epp_lotar); homecache_change_page_home(priv->eq_pages, EQ_ORDER, epp_home); } /* * Register the EPP shared memory queue. */ { netio_ipp_address_t ea = { .va = 0, .pa = __pa(priv->eq), .pte = hv_pte(0), .size = EQ_SIZE, }; ea.pte = hv_pte_set_lotar(ea.pte, epp_lotar); ea.pte = hv_pte_set_mode(ea.pte, HV_PTE_MODE_CACHE_TILE_L3); ret = hv_dev_pwrite(priv->hv_devhdl, 0, (HV_VirtAddr)&ea, sizeof(ea), NETIO_EPP_SHM_OFF); if (ret < 0) return -EIO; } /* * Start LIPP/LEPP. */ if (hv_dev_pwrite(priv->hv_devhdl, 0, (HV_VirtAddr)&dummy, sizeof(dummy), NETIO_IPP_START_SHIM_OFF) < 0) { pr_warning("Failed to start LIPP/LEPP.\n"); return -EIO; } return 0; } /* * Register with hypervisor on the current CPU. * * Strangely, this function does important things even if it "fails", * which is especially common if the link is not up yet. Hopefully * these things are all "harmless" if done twice! */ static void tile_net_register(void *dev_ptr) { struct net_device *dev = (struct net_device *)dev_ptr; struct tile_net_priv *priv = netdev_priv(dev); int my_cpu = smp_processor_id(); struct tile_net_cpu *info; struct tile_netio_queue *queue; /* Only network cpus can receive packets. */ int queue_id = cpumask_test_cpu(my_cpu, &priv->network_cpus_map) ? 0 : 255; netio_input_config_t config = { .flags = 0, .num_receive_packets = priv->network_cpus_credits, .queue_id = queue_id }; int ret = 0; netio_queue_impl_t *queuep; PDEBUG("tile_net_register(queue_id %d)\n", queue_id); if (!strcmp(dev->name, "xgbe0")) info = &__get_cpu_var(hv_xgbe0); else if (!strcmp(dev->name, "xgbe1")) info = &__get_cpu_var(hv_xgbe1); else if (!strcmp(dev->name, "gbe0")) info = &__get_cpu_var(hv_gbe0); else if (!strcmp(dev->name, "gbe1")) info = &__get_cpu_var(hv_gbe1); else BUG(); /* Initialize the egress timer. */ init_timer(&info->egress_timer); info->egress_timer.data = (long)info; info->egress_timer.function = tile_net_handle_egress_timer; priv->cpu[my_cpu] = info; /* * Register ourselves with LIPP. This does a lot of stuff, * including invoking the LIPP registration code. */ ret = hv_dev_pwrite(priv->hv_devhdl, 0, (HV_VirtAddr)&config, sizeof(netio_input_config_t), NETIO_IPP_INPUT_REGISTER_OFF); PDEBUG("hv_dev_pwrite(NETIO_IPP_INPUT_REGISTER_OFF) returned %d\n", ret); if (ret < 0) { if (ret != NETIO_LINK_DOWN) { printk(KERN_DEBUG "hv_dev_pwrite " "NETIO_IPP_INPUT_REGISTER_OFF failure %d\n", ret); } info->link_down = (ret == NETIO_LINK_DOWN); return; } /* * Get the pointer to our queue's system part. */ ret = hv_dev_pread(priv->hv_devhdl, 0, (HV_VirtAddr)&queuep, sizeof(netio_queue_impl_t *), NETIO_IPP_INPUT_REGISTER_OFF); PDEBUG("hv_dev_pread(NETIO_IPP_INPUT_REGISTER_OFF) returned %d\n", ret); PDEBUG("queuep %p\n", queuep); if (ret <= 0) { /* ISSUE: Shouldn't this be a fatal error? */ pr_err("hv_dev_pread NETIO_IPP_INPUT_REGISTER_OFF failure\n"); return; } queue = &info->queue; queue->__system_part = queuep; memset(&queue->__user_part, 0, sizeof(netio_queue_user_impl_t)); /* This is traditionally "config.num_receive_packets / 2". */ queue->__user_part.__receive_credit_interval = 4; queue->__user_part.__receive_credit_remaining = queue->__user_part.__receive_credit_interval; /* * Get a fastio index from the hypervisor. * ISSUE: Shouldn't this check the result? */ ret = hv_dev_pread(priv->hv_devhdl, 0, (HV_VirtAddr)&queue->__user_part.__fastio_index, sizeof(queue->__user_part.__fastio_index), NETIO_IPP_GET_FASTIO_OFF); PDEBUG("hv_dev_pread(NETIO_IPP_GET_FASTIO_OFF) returned %d\n", ret); /* Now we are registered. */ info->registered = true; } /* * Deregister with hypervisor on the current CPU. * * This simply discards all our credits, so no more packets will be * delivered to this tile. There may still be packets in our queue. * * Also, disable the ingress interrupt. */ static void tile_net_deregister(void *dev_ptr) { struct net_device *dev = (struct net_device *)dev_ptr; struct tile_net_priv *priv = netdev_priv(dev); int my_cpu = smp_processor_id(); struct tile_net_cpu *info = priv->cpu[my_cpu]; /* Disable the ingress interrupt. */ disable_percpu_irq(priv->intr_id); /* Do nothing else if not registered. */ if (info == NULL || !info->registered) return; { struct tile_netio_queue *queue = &info->queue; netio_queue_user_impl_t *qup = &queue->__user_part; /* Discard all our credits. */ __netio_fastio_return_credits(qup->__fastio_index, -1); } } /* * Unregister with hypervisor on the current CPU. * * Also, disable the ingress interrupt. */ static void tile_net_unregister(void *dev_ptr) { struct net_device *dev = (struct net_device *)dev_ptr; struct tile_net_priv *priv = netdev_priv(dev); int my_cpu = smp_processor_id(); struct tile_net_cpu *info = priv->cpu[my_cpu]; int ret; int dummy = 0; /* Disable the ingress interrupt. */ disable_percpu_irq(priv->intr_id); /* Do nothing else if not registered. */ if (info == NULL || !info->registered) return; /* Unregister ourselves with LIPP/LEPP. */ ret = hv_dev_pwrite(priv->hv_devhdl, 0, (HV_VirtAddr)&dummy, sizeof(dummy), NETIO_IPP_INPUT_UNREGISTER_OFF); if (ret < 0) panic("Failed to unregister with LIPP/LEPP!\n"); /* Discard all packets still in our NetIO queue. */ tile_net_discard_packets(dev); /* Reset state. */ info->num_needed_small_buffers = 0; info->num_needed_large_buffers = 0; /* Cancel egress timer. */ del_timer(&info->egress_timer); info->egress_timer_scheduled = false; } /* * Helper function for "tile_net_stop()". * * Also used to handle registration failure in "tile_net_open_inner()", * when the various extra steps in "tile_net_stop()" are not necessary. */ static void tile_net_stop_aux(struct net_device *dev) { struct tile_net_priv *priv = netdev_priv(dev); int i; int dummy = 0; /* * Unregister all tiles, so LIPP will stop delivering packets. * Also, delete all the "napi" objects (sequentially, to protect * "dev->napi_list"). */ on_each_cpu(tile_net_unregister, (void *)dev, 1); for_each_online_cpu(i) { struct tile_net_cpu *info = priv->cpu[i]; if (info != NULL && info->registered) { netif_napi_del(&info->napi); info->registered = false; } } /* Stop LIPP/LEPP. */ if (hv_dev_pwrite(priv->hv_devhdl, 0, (HV_VirtAddr)&dummy, sizeof(dummy), NETIO_IPP_STOP_SHIM_OFF) < 0) panic("Failed to stop LIPP/LEPP!\n"); priv->partly_opened = 0; } /* * Disable NAPI for the given device on the current cpu. */ static void tile_net_stop_disable(void *dev_ptr) { struct net_device *dev = (struct net_device *)dev_ptr; struct tile_net_priv *priv = netdev_priv(dev); int my_cpu = smp_processor_id(); struct tile_net_cpu *info = priv->cpu[my_cpu]; /* Disable NAPI if needed. */ if (info != NULL && info->napi_enabled) { napi_disable(&info->napi); info->napi_enabled = false; } } /* * Enable NAPI and the ingress interrupt for the given device * on the current cpu. * * ISSUE: Only do this for "network cpus"? */ static void tile_net_open_enable(void *dev_ptr) { struct net_device *dev = (struct net_device *)dev_ptr; struct tile_net_priv *priv = netdev_priv(dev); int my_cpu = smp_processor_id(); struct tile_net_cpu *info = priv->cpu[my_cpu]; /* Enable NAPI. */ napi_enable(&info->napi); info->napi_enabled = true; /* Enable the ingress interrupt. */ enable_percpu_irq(priv->intr_id); } /* * tile_net_open_inner does most of the work of bringing up the interface. * It's called from tile_net_open(), and also from tile_net_retry_open(). * The return value is 0 if the interface was brought up, < 0 if * tile_net_open() should return the return value as an error, and > 0 if * tile_net_open() should return success and schedule a work item to * periodically retry the bringup. */ static int tile_net_open_inner(struct net_device *dev) { struct tile_net_priv *priv = netdev_priv(dev); int my_cpu = smp_processor_id(); struct tile_net_cpu *info; struct tile_netio_queue *queue; int result = 0; int i; int dummy = 0; /* * First try to register just on the local CPU, and handle any * semi-expected "link down" failure specially. Note that we * do NOT call "tile_net_stop_aux()", unlike below. */ tile_net_register(dev); info = priv->cpu[my_cpu]; if (!info->registered) { if (info->link_down) return 1; return -EAGAIN; } /* * Now register everywhere else. If any registration fails, * even for "link down" (which might not be possible), we * clean up using "tile_net_stop_aux()". Also, add all the * "napi" objects (sequentially, to protect "dev->napi_list"). * ISSUE: Only use "netif_napi_add()" for "network cpus"? */ smp_call_function(tile_net_register, (void *)dev, 1); for_each_online_cpu(i) { struct tile_net_cpu *info = priv->cpu[i]; if (info->registered) netif_napi_add(dev, &info->napi, tile_net_poll, 64); else result = -EAGAIN; } if (result != 0) { tile_net_stop_aux(dev); return result; } queue = &info->queue; if (priv->intr_id == 0) { unsigned int irq; /* * Acquire the irq allocated by the hypervisor. Every * queue gets the same irq. The "__intr_id" field is * "1 << irq", so we use "__ffs()" to extract "irq". */ priv->intr_id = queue->__system_part->__intr_id; BUG_ON(priv->intr_id == 0); irq = __ffs(priv->intr_id); /* * Register the ingress interrupt handler for this * device, permanently. * * We used to call "free_irq()" in "tile_net_stop()", * and then re-register the handler here every time, * but that caused DNP errors in "handle_IRQ_event()" * because "desc->action" was NULL. See bug 9143. */ tile_irq_activate(irq, TILE_IRQ_PERCPU); BUG_ON(request_irq(irq, tile_net_handle_ingress_interrupt, 0, dev->name, (void *)dev) != 0); } { /* Allocate initial buffers. */ int max_buffers = priv->network_cpus_count * priv->network_cpus_credits; info->num_needed_small_buffers = min(LIPP_SMALL_BUFFERS, max_buffers); info->num_needed_large_buffers = min(LIPP_LARGE_BUFFERS, max_buffers); tile_net_provide_needed_buffers(info); if (info->num_needed_small_buffers != 0 || info->num_needed_large_buffers != 0) panic("Insufficient memory for buffer stack!"); } /* We are about to be active. */ priv->active = true; /* Make sure "active" is visible to all tiles. */ mb(); /* On each tile, enable NAPI and the ingress interrupt. */ on_each_cpu(tile_net_open_enable, (void *)dev, 1); /* Start LIPP/LEPP and activate "ingress" at the shim. */ if (hv_dev_pwrite(priv->hv_devhdl, 0, (HV_VirtAddr)&dummy, sizeof(dummy), NETIO_IPP_INPUT_INIT_OFF) < 0) panic("Failed to activate the LIPP Shim!\n"); /* Start our transmit queue. */ netif_start_queue(dev); return 0; } /* * Called periodically to retry bringing up the NetIO interface, * if it doesn't come up cleanly during tile_net_open(). */ static void tile_net_open_retry(struct work_struct *w) { struct delayed_work *dw = container_of(w, struct delayed_work, work); struct tile_net_priv *priv = container_of(dw, struct tile_net_priv, retry_work); /* * Try to bring the NetIO interface up. If it fails, reschedule * ourselves to try again later; otherwise, tell Linux we now have * a working link. ISSUE: What if the return value is negative? */ if (tile_net_open_inner(priv->dev) != 0) schedule_delayed_work(&priv->retry_work, TILE_NET_RETRY_INTERVAL); else netif_carrier_on(priv->dev); } /* * Called when a network interface is made active. * * Returns 0 on success, negative value on failure. * * The open entry point is called when a network interface is made * active by the system (IFF_UP). At this point all resources needed * for transmit and receive operations are allocated, the interrupt * handler is registered with the OS (if needed), the watchdog timer * is started, and the stack is notified that the interface is ready. * * If the actual link is not available yet, then we tell Linux that * we have no carrier, and we keep checking until the link comes up. */ static int tile_net_open(struct net_device *dev) { int ret = 0; struct tile_net_priv *priv = netdev_priv(dev); /* * We rely on priv->partly_opened to tell us if this is the * first time this interface is being brought up. If it is * set, the IPP was already initialized and should not be * initialized again. */ if (!priv->partly_opened) { int count; int credits; /* Initialize LIPP/LEPP, and start the Shim. */ ret = tile_net_open_aux(dev); if (ret < 0) { pr_err("tile_net_open_aux failed: %d\n", ret); return ret; } /* Analyze the network cpus. */ if (network_cpus_used) cpumask_copy(&priv->network_cpus_map, &network_cpus_map); else cpumask_copy(&priv->network_cpus_map, cpu_online_mask); count = cpumask_weight(&priv->network_cpus_map); /* Limit credits to available buffers, and apply min. */ credits = max(16, (LIPP_LARGE_BUFFERS / count) & ~1); /* Apply "GBE" max limit. */ /* ISSUE: Use higher limit for XGBE? */ credits = min(NETIO_MAX_RECEIVE_PKTS, credits); priv->network_cpus_count = count; priv->network_cpus_credits = credits; #ifdef TILE_NET_DEBUG pr_info("Using %d network cpus, with %d credits each\n", priv->network_cpus_count, priv->network_cpus_credits); #endif priv->partly_opened = 1; } else { /* FIXME: Is this possible? */ /* printk("Already partly opened.\n"); */ } /* * Attempt to bring up the link. */ ret = tile_net_open_inner(dev); if (ret <= 0) { if (ret == 0) netif_carrier_on(dev); return ret; } /* * We were unable to bring up the NetIO interface, but we want to * try again in a little bit. Tell Linux that we have no carrier * so it doesn't try to use the interface before the link comes up * and then remember to try again later. */ netif_carrier_off(dev); schedule_delayed_work(&priv->retry_work, TILE_NET_RETRY_INTERVAL); return 0; } static int tile_net_drain_lipp_buffers(struct tile_net_priv *priv) { int n = 0; /* Drain all the LIPP buffers. */ while (true) { int buffer; /* NOTE: This should never fail. */ if (hv_dev_pread(priv->hv_devhdl, 0, (HV_VirtAddr)&buffer, sizeof(buffer), NETIO_IPP_DRAIN_OFF) < 0) break; /* Stop when done. */ if (buffer == 0) break; { /* Convert "linux_buffer_t" to "va". */ void *va = __va((phys_addr_t)(buffer >> 1) << 7); /* Acquire the associated "skb". */ struct sk_buff **skb_ptr = va - sizeof(*skb_ptr); struct sk_buff *skb = *skb_ptr; kfree_skb(skb); } n++; } return n; } /* * Disables a network interface. * * Returns 0, this is not allowed to fail. * * The close entry point is called when an interface is de-activated * by the OS. The hardware is still under the drivers control, but * needs to be disabled. A global MAC reset is issued to stop the * hardware, and all transmit and receive resources are freed. * * ISSUE: How closely does "netif_running(dev)" mirror "priv->active"? * * Before we are called by "__dev_close()", "netif_running()" will * have been cleared, so no NEW calls to "tile_net_poll()" will be * made by "netpoll_poll_dev()". * * Often, this can cause some tiles to still have packets in their * queues, so we must call "tile_net_discard_packets()" later. * * Note that some other tile may still be INSIDE "tile_net_poll()", * and in fact, many will be, if there is heavy network load. * * Calling "on_each_cpu(tile_net_stop_disable, (void *)dev, 1)" when * any tile is still "napi_schedule()"'d will induce a horrible crash * when "msleep()" is called. This includes tiles which are inside * "tile_net_poll()" which have not yet called "napi_complete()". * * So, we must first try to wait long enough for other tiles to finish * with any current "tile_net_poll()" call, and, hopefully, to clear * the "scheduled" flag. ISSUE: It is unclear what happens to tiles * which have called "napi_schedule()" but which had not yet tried to * call "tile_net_poll()", or which exhausted their budget inside * "tile_net_poll()" just before this function was called. */ static int tile_net_stop(struct net_device *dev) { struct tile_net_priv *priv = netdev_priv(dev); PDEBUG("tile_net_stop()\n"); /* Start discarding packets. */ priv->active = false; /* Make sure "active" is visible to all tiles. */ mb(); /* * On each tile, make sure no NEW packets get delivered, and * disable the ingress interrupt. * * Note that the ingress interrupt can fire AFTER this, * presumably due to packets which were recently delivered, * but it will have no effect. */ on_each_cpu(tile_net_deregister, (void *)dev, 1); /* Optimistically drain LIPP buffers. */ (void)tile_net_drain_lipp_buffers(priv); /* ISSUE: Only needed if not yet fully open. */ cancel_delayed_work_sync(&priv->retry_work); /* Can't transmit any more. */ netif_stop_queue(dev); /* Disable NAPI on each tile. */ on_each_cpu(tile_net_stop_disable, (void *)dev, 1); /* * Drain any remaining LIPP buffers. NOTE: This "printk()" * has never been observed, but in theory it could happen. */ if (tile_net_drain_lipp_buffers(priv) != 0) printk("Had to drain some extra LIPP buffers!\n"); /* Stop LIPP/LEPP. */ tile_net_stop_aux(dev); /* * ISSUE: It appears that, in practice anyway, by the time we * get here, there are no pending completions, but just in case, * we free (all of) them anyway. */ while (tile_net_lepp_free_comps(dev, true)) /* loop */; /* Wipe the EPP queue, and wait till the stores hit the EPP. */ memset(priv->eq, 0, sizeof(lepp_queue_t)); mb(); return 0; } /* * Prepare the "frags" info for the resulting LEPP command. * * If needed, flush the memory used by the frags. */ static unsigned int tile_net_tx_frags(lepp_frag_t *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); phys_addr_t cpa; if (b_len != 0) { if (!hash_default) finv_buffer_remote(b_data, b_len, 0); cpa = __pa(b_data); frags[n].cpa_lo = cpa; frags[n].cpa_hi = cpa >> 32; frags[n].length = b_len; frags[n].hash_for_home = hash_default; n++; } for (i = 0; i < sh->nr_frags; i++) { skb_frag_t *f = &sh->frags[i]; unsigned long pfn = page_to_pfn(f->page); /* FIXME: Compute "hash_for_home" properly. */ /* ISSUE: The hypervisor checks CHIP_HAS_REV1_DMA_PACKETS(). */ int hash_for_home = hash_default; /* FIXME: Hmmm. */ if (!hash_default) { void *va = pfn_to_kaddr(pfn) + f->page_offset; BUG_ON(PageHighMem(f->page)); finv_buffer_remote(va, f->size, 0); } cpa = ((phys_addr_t)pfn << PAGE_SHIFT) + f->page_offset; frags[n].cpa_lo = cpa; frags[n].cpa_hi = cpa >> 32; frags[n].length = skb_frag_size(f); frags[n].hash_for_home = hash_for_home; n++; } return n; } /* * This function takes "skb", consisting of a header template and a * payload, and hands it to LEPP, to emit as one or more segments, * each consisting of a possibly modified header, plus a piece of the * payload, via a process known as "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. * * In theory, "sh->nr_frags" could be 3, but in practice, it seems * that this will never actually happen. * * See "emulate_large_send_offload()" for some reference code, which * does not handle checksumming. * * ISSUE: How do we make sure that high memory DMA does not migrate? */ static int tile_net_tx_tso(struct sk_buff *skb, struct net_device *dev) { struct tile_net_priv *priv = netdev_priv(dev); int my_cpu = smp_processor_id(); struct tile_net_cpu *info = priv->cpu[my_cpu]; struct tile_net_stats_t *stats = &info->stats; struct skb_shared_info *sh = skb_shinfo(skb); 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 == ih", 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. */ /* NOTE: This may be less than skb_headlen(skb). */ unsigned int sh_len = eh_len + ih_len + th_len; /* The number of payload bytes at "skb->data + sh_len". */ /* This is non-zero for sendfile() without HIGHDMA. */ unsigned int b_len = skb_headlen(skb) - sh_len; /* The total number of payload bytes. */ unsigned int d_len = b_len + skb->data_len; /* The maximum payload size. */ unsigned int p_len = sh->gso_size; /* The total number of segments. */ unsigned int num_segs = sh->gso_segs; /* The temporary copy of the command. */ u32 cmd_body[(LEPP_MAX_CMD_SIZE + 3) / 4]; lepp_tso_cmd_t *cmd = (lepp_tso_cmd_t *)cmd_body; /* Analyze the "frags". */ unsigned int num_frags = tile_net_tx_frags(cmd->frags, skb, data + sh_len, b_len); /* The size of the command, including frags and header. */ size_t cmd_size = LEPP_TSO_CMD_SIZE(num_frags, sh_len); /* The command header. */ lepp_tso_cmd_t cmd_init = { .tso = true, .header_size = sh_len, .ip_offset = eh_len, .tcp_offset = eh_len + ih_len, .payload_size = p_len, .num_frags = num_frags, }; unsigned long irqflags; lepp_queue_t *eq = priv->eq; struct sk_buff *olds[8]; unsigned int wanted = 8; unsigned int i, nolds = 0; unsigned int cmd_head, cmd_tail, cmd_next; unsigned int comp_tail; /* Paranoia. */ BUG_ON(skb->protocol != htons(ETH_P_IP)); BUG_ON(ih->protocol != IPPROTO_TCP); BUG_ON(skb->ip_summed != CHECKSUM_PARTIAL); BUG_ON(num_frags > LEPP_MAX_FRAGS); /*--BUG_ON(num_segs != (d_len + (p_len - 1)) / p_len); */ BUG_ON(num_segs <= 1); /* Finish preparing the command. */ /* Copy the command header. */ *cmd = cmd_init; /* Copy the "header". */ memcpy(&cmd->frags[num_frags], data, sh_len); /* Prefetch and wait, to minimize time spent holding the spinlock. */ prefetch_L1(&eq->comp_tail); prefetch_L1(&eq->cmd_tail); mb(); /* Enqueue the command. */ spin_lock_irqsave(&priv->eq_lock, irqflags); /* * Handle completions if needed to make room. * HACK: Spin until there is sufficient room. */ if (lepp_num_free_comp_slots(eq) == 0) { nolds = tile_net_lepp_grab_comps(eq, olds, wanted, 0); if (nolds == 0) { busy: spin_unlock_irqrestore(&priv->eq_lock, irqflags); return NETDEV_TX_BUSY; } } cmd_head = eq->cmd_head; cmd_tail = eq->cmd_tail; /* Prepare to advance, detecting full queue. */ cmd_next = cmd_tail + cmd_size; if (cmd_tail < cmd_head && cmd_next >= cmd_head) goto busy; if (cmd_next > LEPP_CMD_LIMIT) { cmd_next = 0; if (cmd_next == cmd_head) goto busy; } /* Copy the command. */ memcpy(&eq->cmds[cmd_tail], cmd, cmd_size); /* Advance. */ cmd_tail = cmd_next; /* Record "skb" for eventual freeing. */ comp_tail = eq->comp_tail; eq->comps[comp_tail] = skb; LEPP_QINC(comp_tail); eq->comp_tail = comp_tail; /* Flush before allowing LEPP to handle the command. */ /* ISSUE: Is this the optimal location for the flush? */ __insn_mf(); eq->cmd_tail = cmd_tail; /* NOTE: Using "4" here is more efficient than "0" or "2", */ /* and, strangely, more efficient than pre-checking the number */ /* of available completions, and comparing it to 4. */ if (nolds == 0) nolds = tile_net_lepp_grab_comps(eq, olds, wanted, 4); spin_unlock_irqrestore(&priv->eq_lock, irqflags); /* Handle completions. */ for (i = 0; i < nolds; i++) kfree_skb(olds[i]); /* Update stats. */ stats->tx_packets += num_segs; stats->tx_bytes += (num_segs * sh_len) + d_len; /* Make sure the egress timer is scheduled. */ tile_net_schedule_egress_timer(info); return NETDEV_TX_OK; } /* * Transmit a packet (called by the kernel via "hard_start_xmit" hook). */ static int tile_net_tx(struct sk_buff *skb, struct net_device *dev) { struct tile_net_priv *priv = netdev_priv(dev); int my_cpu = smp_processor_id(); struct tile_net_cpu *info = priv->cpu[my_cpu]; struct tile_net_stats_t *stats = &info->stats; unsigned long irqflags; struct skb_shared_info *sh = skb_shinfo(skb); unsigned int len = skb->len; unsigned char *data = skb->data; unsigned int csum_start = skb_checksum_start_offset(skb); lepp_frag_t frags[LEPP_MAX_FRAGS]; unsigned int num_frags; lepp_queue_t *eq = priv->eq; struct sk_buff *olds[8]; unsigned int wanted = 8; unsigned int i, nolds = 0; unsigned int cmd_size = sizeof(lepp_cmd_t); unsigned int cmd_head, cmd_tail, cmd_next; unsigned int comp_tail; lepp_cmd_t cmds[LEPP_MAX_FRAGS]; /* * This is paranoia, since we think that if the link doesn't come * up, telling Linux we have no carrier will keep it from trying * to transmit. If it does, though, we can't execute this routine, * since data structures we depend on aren't set up yet. */ if (!info->registered) return NETDEV_TX_BUSY; /* Save the timestamp. */ dev->trans_start = jiffies; #ifdef TILE_NET_PARANOIA #if CHIP_HAS_CBOX_HOME_MAP() if (hash_default) { HV_PTE pte = *virt_to_pte(current->mm, (unsigned long)data); if (hv_pte_get_mode(pte) != HV_PTE_MODE_CACHE_HASH_L3) panic("Non-HFH egress buffer! VA=%p Mode=%d PTE=%llx", data, hv_pte_get_mode(pte), hv_pte_val(pte)); } #endif #endif #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); /* Prepare the commands. */ num_frags = tile_net_tx_frags(frags, skb, data, skb_headlen(skb)); for (i = 0; i < num_frags; i++) { bool final = (i == num_frags - 1); lepp_cmd_t cmd = { .cpa_lo = frags[i].cpa_lo, .cpa_hi = frags[i].cpa_hi, .length = frags[i].length, .hash_for_home = frags[i].hash_for_home, .send_completion = final, .end_of_packet = final }; if (i == 0 && skb->ip_summed == CHECKSUM_PARTIAL) { cmd.compute_checksum = 1; cmd.checksum_data.bits.start_byte = csum_start; cmd.checksum_data.bits.count = len - csum_start; cmd.checksum_data.bits.destination_byte = csum_start + skb->csum_offset; } cmds[i] = cmd; } /* Prefetch and wait, to minimize time spent holding the spinlock. */ prefetch_L1(&eq->comp_tail); prefetch_L1(&eq->cmd_tail); mb(); /* Enqueue the commands. */ spin_lock_irqsave(&priv->eq_lock, irqflags); /* * Handle completions if needed to make room. * HACK: Spin until there is sufficient room. */ if (lepp_num_free_comp_slots(eq) == 0) { nolds = tile_net_lepp_grab_comps(eq, olds, wanted, 0); if (nolds == 0) { busy: spin_unlock_irqrestore(&priv->eq_lock, irqflags); return NETDEV_TX_BUSY; } } cmd_head = eq->cmd_head; cmd_tail = eq->cmd_tail; /* Copy the commands, or fail. */ for (i = 0; i < num_frags; i++) { /* Prepare to advance, detecting full queue. */ cmd_next = cmd_tail + cmd_size; if (cmd_tail < cmd_head && cmd_next >= cmd_head) goto busy; if (cmd_next > LEPP_CMD_LIMIT) { cmd_next = 0; if (cmd_next == cmd_head) goto busy; } /* Copy the command. */ *(lepp_cmd_t *)&eq->cmds[cmd_tail] = cmds[i]; /* Advance. */ cmd_tail = cmd_next; } /* Record "skb" for eventual freeing. */ comp_tail = eq->comp_tail; eq->comps[comp_tail] = skb; LEPP_QINC(comp_tail); eq->comp_tail = comp_tail; /* Flush before allowing LEPP to handle the command. */ /* ISSUE: Is this the optimal location for the flush? */ __insn_mf(); eq->cmd_tail = cmd_tail; /* NOTE: Using "4" here is more efficient than "0" or "2", */ /* and, strangely, more efficient than pre-checking the number */ /* of available completions, and comparing it to 4. */ if (nolds == 0) nolds = tile_net_lepp_grab_comps(eq, olds, wanted, 4); spin_unlock_irqrestore(&priv->eq_lock, irqflags); /* Handle completions. */ for (i = 0; i < nolds; i++) kfree_skb(olds[i]); /* HACK: Track "expanded" size for short packets (e.g. 42 < 60). */ stats->tx_packets++; stats->tx_bytes += ((len >= ETH_ZLEN) ? len : ETH_ZLEN); /* 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) { PDEBUG("tile_net_tx_timeout()\n"); PDEBUG("Transmit timeout at %ld, latency %ld\n", jiffies, jiffies - dev->trans_start); /* XXX: 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); u32 rx_packets = 0; u32 tx_packets = 0; u32 rx_bytes = 0; u32 tx_bytes = 0; int i; for_each_online_cpu(i) { if (priv->cpu[i]) { rx_packets += priv->cpu[i]->stats.rx_packets; rx_bytes += priv->cpu[i]->stats.rx_bytes; tx_packets += priv->cpu[i]->stats.tx_packets; tx_bytes += priv->cpu[i]->stats.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". * * The "change_mtu" method is usually not needed. * If you need it, it must be like this. */ static int tile_net_change_mtu(struct net_device *dev, int new_mtu) { PDEBUG("tile_net_change_mtu()\n"); /* 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 IPP 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 the NetIO program or kernel driver which is actually * handling them. * * 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; /* ISSUE: Note that "dev_addr" is now a pointer. */ memcpy(dev->dev_addr, addr->sa_data, dev->addr_len); return 0; } /* * Obtain the MAC address from the hypervisor. * This must be done before opening the device. */ static int tile_net_get_mac(struct net_device *dev) { struct tile_net_priv *priv = netdev_priv(dev); char hv_dev_name[32]; int len; __netio_getset_offset_t offset = { .word = NETIO_IPP_PARAM_OFF }; int ret; /* For example, "xgbe0". */ strcpy(hv_dev_name, dev->name); len = strlen(hv_dev_name); /* For example, "xgbe/0". */ hv_dev_name[len] = hv_dev_name[len - 1]; hv_dev_name[len - 1] = '/'; len++; /* For example, "xgbe/0/native_hash". */ strcpy(hv_dev_name + len, hash_default ? "/native_hash" : "/native"); /* Get the hypervisor handle for this device. */ priv->hv_devhdl = hv_dev_open((HV_VirtAddr)hv_dev_name, 0); PDEBUG("hv_dev_open(%s) returned %d %p\n", hv_dev_name, priv->hv_devhdl, &priv->hv_devhdl); if (priv->hv_devhdl < 0) { if (priv->hv_devhdl == HV_ENODEV) printk(KERN_DEBUG "Ignoring unconfigured device %s\n", hv_dev_name); else printk(KERN_DEBUG "hv_dev_open(%s) returned %d\n", hv_dev_name, priv->hv_devhdl); return -1; } /* * Read the hardware address from the hypervisor. * ISSUE: Note that "dev_addr" is now a pointer. */ offset.bits.class = NETIO_PARAM; offset.bits.addr = NETIO_PARAM_MAC; ret = hv_dev_pread(priv->hv_devhdl, 0, (HV_VirtAddr)dev->dev_addr, dev->addr_len, offset.word); PDEBUG("hv_dev_pread(NETIO_PARAM_MAC) returned %d\n", ret); if (ret <= 0) { printk(KERN_DEBUG "hv_dev_pread(NETIO_PARAM_MAC) %s failed\n", dev->name); /* * Since the device is configured by the hypervisor but we * can't get its MAC address, we are most likely running * the simulator, so let's generate a random MAC address. */ random_ether_addr(dev->dev_addr); } return 0; } static 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 }; /* * 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) { PDEBUG("tile_net_setup()\n"); 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; /* We support TSO. */ dev->features |= NETIF_F_TSO; #ifdef TILE_NET_GSO /* We support GSO. */ dev->features |= NETIF_F_GSO; #endif if (hash_default) dev->features |= NETIF_F_HIGHDMA; /* ISSUE: We should support NETIF_F_UFO. */ dev->tx_queue_len = TILE_NET_TX_QUEUE_LEN; dev->mtu = TILE_NET_MTU; } /* * Allocate the device structure, register the device, and obtain the * MAC address from the hypervisor. */ static struct net_device *tile_net_dev_init(const char *name) { int ret; struct net_device *dev; struct tile_net_priv *priv; /* * 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 NULL; } priv = netdev_priv(dev); /* Initialize "priv". */ memset(priv, 0, sizeof(*priv)); /* Save "dev" for "tile_net_open_retry()". */ priv->dev = dev; INIT_DELAYED_WORK(&priv->retry_work, tile_net_open_retry); spin_lock_init(&priv->eq_lock); /* Allocate "eq". */ priv->eq_pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, EQ_ORDER); if (!priv->eq_pages) { free_netdev(dev); return NULL; } priv->eq = page_address(priv->eq_pages); /* Register the network device. */ ret = register_netdev(dev); if (ret) { pr_err("register_netdev %s failed %d\n", dev->name, ret); __free_pages(priv->eq_pages, EQ_ORDER); free_netdev(dev); return NULL; } /* Get the MAC address. */ ret = tile_net_get_mac(dev); if (ret < 0) { unregister_netdev(dev); __free_pages(priv->eq_pages, EQ_ORDER); free_netdev(dev); return NULL; } return dev; } /* * Module cleanup. * * FIXME: If compiled as a module, this module cannot be "unloaded", * because the "ingress interrupt handler" is registered permanently. */ static void tile_net_cleanup(void) { int i; for (i = 0; i < TILE_NET_DEVS; i++) { if (tile_net_devs[i]) { struct net_device *dev = tile_net_devs[i]; struct tile_net_priv *priv = netdev_priv(dev); unregister_netdev(dev); finv_buffer_remote(priv->eq, EQ_SIZE, 0); __free_pages(priv->eq_pages, EQ_ORDER); free_netdev(dev); } } } /* * Module initialization. */ static int tile_net_init_module(void) { pr_info("Tilera IPP Net Driver\n"); tile_net_devs[0] = tile_net_dev_init("xgbe0"); tile_net_devs[1] = tile_net_dev_init("xgbe1"); tile_net_devs[2] = tile_net_dev_init("gbe0"); tile_net_devs[3] = tile_net_dev_init("gbe1"); return 0; } module_init(tile_net_init_module); module_exit(tile_net_cleanup); #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); 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); #endif