/*
* 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");
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