diff options
Diffstat (limited to 'drivers/misc/sgi-xp/xpnet.c')
| -rw-r--r-- | drivers/misc/sgi-xp/xpnet.c | 599 |
1 files changed, 599 insertions, 0 deletions
diff --git a/drivers/misc/sgi-xp/xpnet.c b/drivers/misc/sgi-xp/xpnet.c new file mode 100644 index 000000000..2396ba3b0 --- /dev/null +++ b/drivers/misc/sgi-xp/xpnet.c @@ -0,0 +1,599 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * (C) Copyright 2020 Hewlett Packard Enterprise Development LP + * Copyright (C) 1999-2009 Silicon Graphics, Inc. All rights reserved. + */ + +/* + * Cross Partition Network Interface (XPNET) support + * + * XPNET provides a virtual network layered on top of the Cross + * Partition communication layer. + * + * XPNET provides direct point-to-point and broadcast-like support + * for an ethernet-like device. The ethernet broadcast medium is + * replaced with a point-to-point message structure which passes + * pointers to a DMA-capable block that a remote partition should + * retrieve and pass to the upper level networking layer. + * + */ + +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/netdevice.h> +#include <linux/etherdevice.h> +#include "xp.h" + +/* + * The message payload transferred by XPC. + * + * buf_pa is the physical address where the DMA should pull from. + * + * NOTE: for performance reasons, buf_pa should _ALWAYS_ begin on a + * cacheline boundary. To accomplish this, we record the number of + * bytes from the beginning of the first cacheline to the first useful + * byte of the skb (leadin_ignore) and the number of bytes from the + * last useful byte of the skb to the end of the last cacheline + * (tailout_ignore). + * + * size is the number of bytes to transfer which includes the skb->len + * (useful bytes of the senders skb) plus the leadin and tailout + */ +struct xpnet_message { + u16 version; /* Version for this message */ + u16 embedded_bytes; /* #of bytes embedded in XPC message */ + u32 magic; /* Special number indicating this is xpnet */ + unsigned long buf_pa; /* phys address of buffer to retrieve */ + u32 size; /* #of bytes in buffer */ + u8 leadin_ignore; /* #of bytes to ignore at the beginning */ + u8 tailout_ignore; /* #of bytes to ignore at the end */ + unsigned char data; /* body of small packets */ +}; + +/* + * Determine the size of our message, the cacheline aligned size, + * and then the number of message will request from XPC. + * + * XPC expects each message to exist in an individual cacheline. + */ +#define XPNET_MSG_SIZE XPC_MSG_PAYLOAD_MAX_SIZE +#define XPNET_MSG_DATA_MAX \ + (XPNET_MSG_SIZE - offsetof(struct xpnet_message, data)) +#define XPNET_MSG_NENTRIES (PAGE_SIZE / XPC_MSG_MAX_SIZE) + +#define XPNET_MAX_KTHREADS (XPNET_MSG_NENTRIES + 1) +#define XPNET_MAX_IDLE_KTHREADS (XPNET_MSG_NENTRIES + 1) + +/* + * Version number of XPNET implementation. XPNET can always talk to versions + * with same major #, and never talk to versions with a different version. + */ +#define _XPNET_VERSION(_major, _minor) (((_major) << 4) | (_minor)) +#define XPNET_VERSION_MAJOR(_v) ((_v) >> 4) +#define XPNET_VERSION_MINOR(_v) ((_v) & 0xf) + +#define XPNET_VERSION _XPNET_VERSION(1, 0) /* version 1.0 */ +#define XPNET_VERSION_EMBED _XPNET_VERSION(1, 1) /* version 1.1 */ +#define XPNET_MAGIC 0x88786984 /* "XNET" */ + +#define XPNET_VALID_MSG(_m) \ + ((XPNET_VERSION_MAJOR(_m->version) == XPNET_VERSION_MAJOR(XPNET_VERSION)) \ + && (msg->magic == XPNET_MAGIC)) + +#define XPNET_DEVICE_NAME "xp0" + +/* + * When messages are queued with xpc_send_notify, a kmalloc'd buffer + * of the following type is passed as a notification cookie. When the + * notification function is called, we use the cookie to decide + * whether all outstanding message sends have completed. The skb can + * then be released. + */ +struct xpnet_pending_msg { + struct sk_buff *skb; + atomic_t use_count; +}; + +static struct net_device *xpnet_device; + +/* + * When we are notified of other partitions activating, we add them to + * our bitmask of partitions to which we broadcast. + */ +static unsigned long *xpnet_broadcast_partitions; +/* protect above */ +static DEFINE_SPINLOCK(xpnet_broadcast_lock); + +/* + * Since the Block Transfer Engine (BTE) is being used for the transfer + * and it relies upon cache-line size transfers, we need to reserve at + * least one cache-line for head and tail alignment. The BTE is + * limited to 8MB transfers. + * + * Testing has shown that changing MTU to greater than 64KB has no effect + * on TCP as the two sides negotiate a Max Segment Size that is limited + * to 64K. Other protocols May use packets greater than this, but for + * now, the default is 64KB. + */ +#define XPNET_MAX_MTU (0x800000UL - L1_CACHE_BYTES) +/* 68 comes from min TCP+IP+MAC header */ +#define XPNET_MIN_MTU 68 +/* 32KB has been determined to be the ideal */ +#define XPNET_DEF_MTU (0x8000UL) + +/* + * The partid is encapsulated in the MAC address beginning in the following + * octet and it consists of two octets. + */ +#define XPNET_PARTID_OCTET 2 + +/* Define the XPNET debug device structures to be used with dev_dbg() et al */ + +static struct device_driver xpnet_dbg_name = { + .name = "xpnet" +}; + +static struct device xpnet_dbg_subname = { + .init_name = "", /* set to "" */ + .driver = &xpnet_dbg_name +}; + +static struct device *xpnet = &xpnet_dbg_subname; + +/* + * Packet was recevied by XPC and forwarded to us. + */ +static void +xpnet_receive(short partid, int channel, struct xpnet_message *msg) +{ + struct sk_buff *skb; + void *dst; + enum xp_retval ret; + + if (!XPNET_VALID_MSG(msg)) { + /* + * Packet with a different XPC version. Ignore. + */ + xpc_received(partid, channel, (void *)msg); + + xpnet_device->stats.rx_errors++; + + return; + } + dev_dbg(xpnet, "received 0x%lx, %d, %d, %d\n", msg->buf_pa, msg->size, + msg->leadin_ignore, msg->tailout_ignore); + + /* reserve an extra cache line */ + skb = dev_alloc_skb(msg->size + L1_CACHE_BYTES); + if (!skb) { + dev_err(xpnet, "failed on dev_alloc_skb(%d)\n", + msg->size + L1_CACHE_BYTES); + + xpc_received(partid, channel, (void *)msg); + + xpnet_device->stats.rx_errors++; + + return; + } + + /* + * The allocated skb has some reserved space. + * In order to use xp_remote_memcpy(), we need to get the + * skb->data pointer moved forward. + */ + skb_reserve(skb, (L1_CACHE_BYTES - ((u64)skb->data & + (L1_CACHE_BYTES - 1)) + + msg->leadin_ignore)); + + /* + * Update the tail pointer to indicate data actually + * transferred. + */ + skb_put(skb, (msg->size - msg->leadin_ignore - msg->tailout_ignore)); + + /* + * Move the data over from the other side. + */ + if ((XPNET_VERSION_MINOR(msg->version) == 1) && + (msg->embedded_bytes != 0)) { + dev_dbg(xpnet, "copying embedded message. memcpy(0x%p, 0x%p, " + "%lu)\n", skb->data, &msg->data, + (size_t)msg->embedded_bytes); + + skb_copy_to_linear_data(skb, &msg->data, + (size_t)msg->embedded_bytes); + } else { + dst = (void *)((u64)skb->data & ~(L1_CACHE_BYTES - 1)); + dev_dbg(xpnet, "transferring buffer to the skb->data area;\n\t" + "xp_remote_memcpy(0x%p, 0x%p, %u)\n", dst, + (void *)msg->buf_pa, msg->size); + + ret = xp_remote_memcpy(xp_pa(dst), msg->buf_pa, msg->size); + if (ret != xpSuccess) { + /* + * !!! Need better way of cleaning skb. Currently skb + * !!! appears in_use and we can't just call + * !!! dev_kfree_skb. + */ + dev_err(xpnet, "xp_remote_memcpy(0x%p, 0x%p, 0x%x) " + "returned error=0x%x\n", dst, + (void *)msg->buf_pa, msg->size, ret); + + xpc_received(partid, channel, (void *)msg); + + xpnet_device->stats.rx_errors++; + + return; + } + } + + dev_dbg(xpnet, "<skb->head=0x%p skb->data=0x%p skb->tail=0x%p " + "skb->end=0x%p skb->len=%d\n", (void *)skb->head, + (void *)skb->data, skb_tail_pointer(skb), skb_end_pointer(skb), + skb->len); + + skb->protocol = eth_type_trans(skb, xpnet_device); + skb->ip_summed = CHECKSUM_UNNECESSARY; + + dev_dbg(xpnet, "passing skb to network layer\n" + "\tskb->head=0x%p skb->data=0x%p skb->tail=0x%p " + "skb->end=0x%p skb->len=%d\n", + (void *)skb->head, (void *)skb->data, skb_tail_pointer(skb), + skb_end_pointer(skb), skb->len); + + xpnet_device->stats.rx_packets++; + xpnet_device->stats.rx_bytes += skb->len + ETH_HLEN; + + netif_rx(skb); + xpc_received(partid, channel, (void *)msg); +} + +/* + * This is the handler which XPC calls during any sort of change in + * state or message reception on a connection. + */ +static void +xpnet_connection_activity(enum xp_retval reason, short partid, int channel, + void *data, void *key) +{ + DBUG_ON(partid < 0 || partid >= xp_max_npartitions); + DBUG_ON(channel != XPC_NET_CHANNEL); + + switch (reason) { + case xpMsgReceived: /* message received */ + DBUG_ON(data == NULL); + + xpnet_receive(partid, channel, (struct xpnet_message *)data); + break; + + case xpConnected: /* connection completed to a partition */ + spin_lock_bh(&xpnet_broadcast_lock); + __set_bit(partid, xpnet_broadcast_partitions); + spin_unlock_bh(&xpnet_broadcast_lock); + + netif_carrier_on(xpnet_device); + + dev_dbg(xpnet, "%s connected to partition %d\n", + xpnet_device->name, partid); + break; + + default: + spin_lock_bh(&xpnet_broadcast_lock); + __clear_bit(partid, xpnet_broadcast_partitions); + spin_unlock_bh(&xpnet_broadcast_lock); + + if (bitmap_empty(xpnet_broadcast_partitions, + xp_max_npartitions)) { + netif_carrier_off(xpnet_device); + } + + dev_dbg(xpnet, "%s disconnected from partition %d\n", + xpnet_device->name, partid); + break; + } +} + +static int +xpnet_dev_open(struct net_device *dev) +{ + enum xp_retval ret; + + dev_dbg(xpnet, "calling xpc_connect(%d, 0x%p, NULL, %ld, %ld, %ld, " + "%ld)\n", XPC_NET_CHANNEL, xpnet_connection_activity, + (unsigned long)XPNET_MSG_SIZE, + (unsigned long)XPNET_MSG_NENTRIES, + (unsigned long)XPNET_MAX_KTHREADS, + (unsigned long)XPNET_MAX_IDLE_KTHREADS); + + ret = xpc_connect(XPC_NET_CHANNEL, xpnet_connection_activity, NULL, + XPNET_MSG_SIZE, XPNET_MSG_NENTRIES, + XPNET_MAX_KTHREADS, XPNET_MAX_IDLE_KTHREADS); + if (ret != xpSuccess) { + dev_err(xpnet, "ifconfig up of %s failed on XPC connect, " + "ret=%d\n", dev->name, ret); + + return -ENOMEM; + } + + dev_dbg(xpnet, "ifconfig up of %s; XPC connected\n", dev->name); + + return 0; +} + +static int +xpnet_dev_stop(struct net_device *dev) +{ + xpc_disconnect(XPC_NET_CHANNEL); + + dev_dbg(xpnet, "ifconfig down of %s; XPC disconnected\n", dev->name); + + return 0; +} + +/* + * Notification that the other end has received the message and + * DMA'd the skb information. At this point, they are done with + * our side. When all recipients are done processing, we + * release the skb and then release our pending message structure. + */ +static void +xpnet_send_completed(enum xp_retval reason, short partid, int channel, + void *__qm) +{ + struct xpnet_pending_msg *queued_msg = (struct xpnet_pending_msg *)__qm; + + DBUG_ON(queued_msg == NULL); + + dev_dbg(xpnet, "message to %d notified with reason %d\n", + partid, reason); + + if (atomic_dec_return(&queued_msg->use_count) == 0) { + dev_dbg(xpnet, "all acks for skb->head=-x%p\n", + (void *)queued_msg->skb->head); + + dev_kfree_skb_any(queued_msg->skb); + kfree(queued_msg); + } +} + +static void +xpnet_send(struct sk_buff *skb, struct xpnet_pending_msg *queued_msg, + u64 start_addr, u64 end_addr, u16 embedded_bytes, int dest_partid) +{ + u8 msg_buffer[XPNET_MSG_SIZE]; + struct xpnet_message *msg = (struct xpnet_message *)&msg_buffer; + u16 msg_size = sizeof(struct xpnet_message); + enum xp_retval ret; + + msg->embedded_bytes = embedded_bytes; + if (unlikely(embedded_bytes != 0)) { + msg->version = XPNET_VERSION_EMBED; + dev_dbg(xpnet, "calling memcpy(0x%p, 0x%p, 0x%lx)\n", + &msg->data, skb->data, (size_t)embedded_bytes); + skb_copy_from_linear_data(skb, &msg->data, + (size_t)embedded_bytes); + msg_size += embedded_bytes - 1; + } else { + msg->version = XPNET_VERSION; + } + msg->magic = XPNET_MAGIC; + msg->size = end_addr - start_addr; + msg->leadin_ignore = (u64)skb->data - start_addr; + msg->tailout_ignore = end_addr - (u64)skb_tail_pointer(skb); + msg->buf_pa = xp_pa((void *)start_addr); + + dev_dbg(xpnet, "sending XPC message to %d:%d\n" + "msg->buf_pa=0x%lx, msg->size=%u, " + "msg->leadin_ignore=%u, msg->tailout_ignore=%u\n", + dest_partid, XPC_NET_CHANNEL, msg->buf_pa, msg->size, + msg->leadin_ignore, msg->tailout_ignore); + + atomic_inc(&queued_msg->use_count); + + ret = xpc_send_notify(dest_partid, XPC_NET_CHANNEL, XPC_NOWAIT, msg, + msg_size, xpnet_send_completed, queued_msg); + if (unlikely(ret != xpSuccess)) + atomic_dec(&queued_msg->use_count); +} + +/* + * Network layer has formatted a packet (skb) and is ready to place it + * "on the wire". Prepare and send an xpnet_message to all partitions + * which have connected with us and are targets of this packet. + * + * MAC-NOTE: For the XPNET driver, the MAC address contains the + * destination partid. If the destination partid octets are 0xffff, + * this packet is to be broadcast to all connected partitions. + */ +static netdev_tx_t +xpnet_dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev) +{ + struct xpnet_pending_msg *queued_msg; + u64 start_addr, end_addr; + short dest_partid; + u16 embedded_bytes = 0; + + dev_dbg(xpnet, ">skb->head=0x%p skb->data=0x%p skb->tail=0x%p " + "skb->end=0x%p skb->len=%d\n", (void *)skb->head, + (void *)skb->data, skb_tail_pointer(skb), skb_end_pointer(skb), + skb->len); + + if (skb->data[0] == 0x33) { + dev_kfree_skb(skb); + return NETDEV_TX_OK; /* nothing needed to be done */ + } + + /* + * The xpnet_pending_msg tracks how many outstanding + * xpc_send_notifies are relying on this skb. When none + * remain, release the skb. + */ + queued_msg = kmalloc(sizeof(struct xpnet_pending_msg), GFP_ATOMIC); + if (queued_msg == NULL) { + dev_warn(xpnet, "failed to kmalloc %ld bytes; dropping " + "packet\n", sizeof(struct xpnet_pending_msg)); + + dev->stats.tx_errors++; + dev_kfree_skb(skb); + return NETDEV_TX_OK; + } + + /* get the beginning of the first cacheline and end of last */ + start_addr = ((u64)skb->data & ~(L1_CACHE_BYTES - 1)); + end_addr = L1_CACHE_ALIGN((u64)skb_tail_pointer(skb)); + + /* calculate how many bytes to embed in the XPC message */ + if (unlikely(skb->len <= XPNET_MSG_DATA_MAX)) { + /* skb->data does fit so embed */ + embedded_bytes = skb->len; + } + + /* + * Since the send occurs asynchronously, we set the count to one + * and begin sending. Any sends that happen to complete before + * we are done sending will not free the skb. We will be left + * with that task during exit. This also handles the case of + * a packet destined for a partition which is no longer up. + */ + atomic_set(&queued_msg->use_count, 1); + queued_msg->skb = skb; + + if (skb->data[0] == 0xff) { + /* we are being asked to broadcast to all partitions */ + for_each_set_bit(dest_partid, xpnet_broadcast_partitions, + xp_max_npartitions) { + + xpnet_send(skb, queued_msg, start_addr, end_addr, + embedded_bytes, dest_partid); + } + } else { + dest_partid = (short)skb->data[XPNET_PARTID_OCTET + 1]; + dest_partid |= (short)skb->data[XPNET_PARTID_OCTET + 0] << 8; + + if (dest_partid >= 0 && + dest_partid < xp_max_npartitions && + test_bit(dest_partid, xpnet_broadcast_partitions) != 0) { + + xpnet_send(skb, queued_msg, start_addr, end_addr, + embedded_bytes, dest_partid); + } + } + + dev->stats.tx_packets++; + dev->stats.tx_bytes += skb->len; + + if (atomic_dec_return(&queued_msg->use_count) == 0) { + dev_kfree_skb(skb); + kfree(queued_msg); + } + + return NETDEV_TX_OK; +} + +/* + * Deal with transmit timeouts coming from the network layer. + */ +static void +xpnet_dev_tx_timeout(struct net_device *dev, unsigned int txqueue) +{ + dev->stats.tx_errors++; +} + +static const struct net_device_ops xpnet_netdev_ops = { + .ndo_open = xpnet_dev_open, + .ndo_stop = xpnet_dev_stop, + .ndo_start_xmit = xpnet_dev_hard_start_xmit, + .ndo_tx_timeout = xpnet_dev_tx_timeout, + .ndo_set_mac_address = eth_mac_addr, + .ndo_validate_addr = eth_validate_addr, +}; + +static int __init +xpnet_init(void) +{ + u8 addr[ETH_ALEN]; + int result; + + if (!is_uv_system()) + return -ENODEV; + + dev_info(xpnet, "registering network device %s\n", XPNET_DEVICE_NAME); + + xpnet_broadcast_partitions = bitmap_zalloc(xp_max_npartitions, + GFP_KERNEL); + if (xpnet_broadcast_partitions == NULL) + return -ENOMEM; + + /* + * use ether_setup() to init the majority of our device + * structure and then override the necessary pieces. + */ + xpnet_device = alloc_netdev(0, XPNET_DEVICE_NAME, NET_NAME_UNKNOWN, + ether_setup); + if (xpnet_device == NULL) { + bitmap_free(xpnet_broadcast_partitions); + return -ENOMEM; + } + + netif_carrier_off(xpnet_device); + + xpnet_device->netdev_ops = &xpnet_netdev_ops; + xpnet_device->mtu = XPNET_DEF_MTU; + xpnet_device->min_mtu = XPNET_MIN_MTU; + xpnet_device->max_mtu = XPNET_MAX_MTU; + + memset(addr, 0, sizeof(addr)); + /* + * Multicast assumes the LSB of the first octet is set for multicast + * MAC addresses. We chose the first octet of the MAC to be unlikely + * to collide with any vendor's officially issued MAC. + */ + addr[0] = 0x02; /* locally administered, no OUI */ + + addr[XPNET_PARTID_OCTET + 1] = xp_partition_id; + addr[XPNET_PARTID_OCTET + 0] = (xp_partition_id >> 8); + eth_hw_addr_set(xpnet_device, addr); + + /* + * ether_setup() sets this to a multicast device. We are + * really not supporting multicast at this time. + */ + xpnet_device->flags &= ~IFF_MULTICAST; + + /* + * No need to checksum as it is a DMA transfer. The BTE will + * report an error if the data is not retrievable and the + * packet will be dropped. + */ + xpnet_device->features = NETIF_F_HW_CSUM; + + result = register_netdev(xpnet_device); + if (result != 0) { + free_netdev(xpnet_device); + bitmap_free(xpnet_broadcast_partitions); + } + + return result; +} + +module_init(xpnet_init); + +static void __exit +xpnet_exit(void) +{ + dev_info(xpnet, "unregistering network device %s\n", + xpnet_device[0].name); + + unregister_netdev(xpnet_device); + free_netdev(xpnet_device); + bitmap_free(xpnet_broadcast_partitions); +} + +module_exit(xpnet_exit); + +MODULE_AUTHOR("Silicon Graphics, Inc."); +MODULE_DESCRIPTION("Cross Partition Network adapter (XPNET)"); +MODULE_LICENSE("GPL"); |