/*
* 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.
*
* Copyright (C) 1999-2008 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/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/delay.h>
#include <linux/ethtool.h>
#include <linux/mii.h>
#include <linux/smp.h>
#include <linux/string.h>
#include <asm/sn/bte.h>
#include <asm/sn/io.h>
#include <asm/sn/sn_sal.h>
#include <asm/types.h>
#include <asm/atomic.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 */
u64 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 (L1_CACHE_BYTES - XPC_MSG_PAYLOAD_OFFSET)
#define XPNET_MSG_DATA_MAX \
(XPNET_MSG_SIZE - (u64)(&((struct xpnet_message *)0)->data))
#define XPNET_MSG_ALIGNED_SIZE (L1_CACHE_ALIGN(XPNET_MSG_SIZE))
#define XPNET_MSG_NENTRIES (PAGE_SIZE / XPNET_MSG_ALIGNED_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 list_head free_list;
struct sk_buff *skb;
atomic_t use_count;
};
/* driver specific structure pointed to by the device structure */
struct xpnet_dev_private {
struct net_device_stats stats;
};
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 u64 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)
/* 32KB has been determined to be the ideal */
#define XPNET_DEF_MTU (0x8000UL)
/*
* The partition id is encapsulated in the MAC address. The following
* define locates the octet the partid is in.
*/
#define XPNET_PARTID_OCTET 1
#define XPNET_LICENSE_OCTET 2
/*
* Define the XPNET debug device structure that is to be used with dev_dbg(),
* dev_err(), dev_warn(), and dev_info().
*/
struct device_driver xpnet_dbg_name = {
.name = "xpnet"
};
struct device xpnet_dbg_subname = {
.bus_id = {0}, /* set to "" */
.driver = &xpnet_dbg_name
};
struct device *xpnet = &xpnet_dbg_subname;
/*
* Packet was recevied by XPC and forwarded to us.
*/
static void
xpnet_receive(partid_t partid, int channel, struct xpnet_message *msg)
{
struct sk_buff *skb;
bte_result_t bret;
struct xpnet_dev_private *priv =
(struct xpnet_dev_private *) xpnet_device->priv;
if (!XPNET_VALID_MSG(msg)) {
/*
* Packet with a different XPC version. Ignore.
*/
xpc_received(partid, channel, (void *) msg);
priv->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);
priv->stats.rx_errors++;
return;
}
/*
* The allocated skb has some reserved space.
* In order to use bte_copy, 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 {
dev_dbg(xpnet, "transferring buffer to the skb->data area;\n\t"
"bte_copy(0x%p, 0x%p, %hu)\n", (void *)msg->buf_pa,
(void *)__pa((u64)skb->data & ~(L1_CACHE_BYTES - 1)),
msg->size);
bret = bte_copy(msg->buf_pa,
__pa((u64)skb->data & ~(L1_CACHE_BYTES - 1)),
msg->size, (BTE_NOTIFY | BTE_WACQUIRE), NULL);
if (bret != BTE_SUCCESS) {
// >>> Need better way of cleaning skb. Currently skb
// >>> appears in_use and we can't just call
// >>> dev_kfree_skb.
dev_err(xpnet, "bte_copy(0x%p, 0x%p, 0x%hx) returned "
"error=0x%x\n", (void *)msg->buf_pa,
(void *)__pa((u64)skb->data &
~(L1_CACHE_BYTES - 1)),
msg->size, bret);
xpc_received(partid, channel, (void *) msg);
priv->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"
KERN_DEBUG "\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->last_rx = jiffies;
priv->stats.rx_packets++;
priv->stats.rx_bytes += skb->len + ETH_HLEN;
netif_rx_ni(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 xpc_retval reason, partid_t partid, int channel,
void *data, void *key)
{
long bp;
DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS);
DBUG_ON(channel != XPC_NET_CHANNEL);
switch(reason) {
case xpcMsgReceived: /* message received */
DBUG_ON(data == NULL);
xpnet_receive(partid, channel, (struct xpnet_message *) data);
break;
case xpcConnected: /* connection completed to a partition */
spin_lock_bh(&xpnet_broadcast_lock);
xpnet_broadcast_partitions |= 1UL << (partid -1 );
bp = xpnet_broadcast_partitions;
spin_unlock_bh(&xpnet_broadcast_lock);
netif_carrier_on(xpnet_device);
dev_dbg(xpnet, "%s connection created to partition %d; "
"xpnet_broadcast_partitions=0x%lx\n",
xpnet_device->name, partid, bp);
break;
default:
spin_lock_bh(&xpnet_broadcast_lock);
xpnet_broadcast_partitions &= ~(1UL << (partid -1 ));
bp = xpnet_broadcast_partitions;
spin_unlock_bh(&xpnet_broadcast_lock);
if (bp == 0) {
netif_carrier_off(xpnet_device);
}
dev_dbg(xpnet, "%s disconnected from partition %d; "
"xpnet_broadcast_partitions=0x%lx\n",
xpnet_device->name, partid, bp);
break;
}
}
static int
xpnet_dev_open(struct net_device *dev)
{
enum xpc_retval ret;
dev_dbg(xpnet, "calling xpc_connect(%d, 0x%p, NULL, %ld, %ld, %ld, "
"%ld)\n", XPC_NET_CHANNEL, xpnet_connection_activity,
XPNET_MSG_SIZE, XPNET_MSG_NENTRIES, XPNET_MAX_KTHREADS,
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 != xpcSuccess) {
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;
}
static int
xpnet_dev_change_mtu(struct net_device *dev, int new_mtu)
{
/* 68 comes from min TCP+IP+MAC header */
if ((new_mtu < 68) || (new_mtu > XPNET_MAX_MTU)) {
dev_err(xpnet, "ifconfig %s mtu %d failed; value must be "
"between 68 and %ld\n", dev->name, new_mtu,
XPNET_MAX_MTU);
return -EINVAL;
}
dev->mtu = new_mtu;
dev_dbg(xpnet, "ifconfig %s mtu set to %d\n", dev->name, new_mtu);
return 0;
}
/*
* Required for the net_device structure.
*/
static int
xpnet_dev_set_config(struct net_device *dev, struct ifmap *new_map)
{
return 0;
}
/*
* Return statistics to the caller.
*/
static struct net_device_stats *
xpnet_dev_get_stats(struct net_device *dev)
{
struct xpnet_dev_private *priv;
priv = (struct xpnet_dev_private *) dev->priv;
return &priv->stats;
}
/*
* 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 xpc_retval reason, partid_t 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);
}
}
/*
* 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 partition_id. If the destination partition id word
* is 0xff, this packet is to broadcast to all partitions.
*/
static int
xpnet_dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct xpnet_pending_msg *queued_msg;
enum xpc_retval ret;
struct xpnet_message *msg;
u64 start_addr, end_addr;
long dp;
u8 second_mac_octet;
partid_t dest_partid;
struct xpnet_dev_private *priv;
u16 embedded_bytes;
priv = (struct xpnet_dev_private *) dev->priv;
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);
/*
* 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));
priv->stats.tx_errors++;
return -ENOMEM;
}
/* 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 */
embedded_bytes = 0;
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;
second_mac_octet = skb->data[XPNET_PARTID_OCTET];
if (second_mac_octet == 0xff) {
/* we are being asked to broadcast to all partitions */
dp = xpnet_broadcast_partitions;
} else if (second_mac_octet != 0) {
dp = xpnet_broadcast_partitions &
(1UL << (second_mac_octet - 1));
} else {
/* 0 is an invalid partid. Ignore */
dp = 0;
}
dev_dbg(xpnet, "destination Partitions mask (dp) = 0x%lx\n", dp);
/*
* If we wanted to allow promiscuous mode to work like an
* unswitched network, this would be a good point to OR in a
* mask of partitions which should be receiving all packets.
*/
/*
* Main send loop.
*/
for (dest_partid = 1; dp && dest_partid < XP_MAX_PARTITIONS;
dest_partid++) {
if (!(dp & (1UL << (dest_partid - 1)))) {
/* not destined for this partition */
continue;
}
/* remove this partition from the destinations mask */
dp &= ~(1UL << (dest_partid - 1));
/* found a partition to send to */
ret = xpc_allocate(dest_partid, XPC_NET_CHANNEL,
XPC_NOWAIT, (void **)&msg);
if (unlikely(ret != xpcSuccess)) {
continue;
}
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);
} 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 = __pa(start_addr);
dev_dbg(xpnet, "sending XPC message to %d:%d\n"
KERN_DEBUG "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, msg,
xpnet_send_completed, queued_msg);
if (unlikely(ret != xpcSuccess)) {
atomic_dec(&queued_msg->use_count);
continue;
}
}
if (atomic_dec_return(&queued_msg->use_count) == 0) {
dev_dbg(xpnet, "no partitions to receive packet destined for "
"%d\n", dest_partid);
dev_kfree_skb(skb);
kfree(queued_msg);
}
priv->stats.tx_packets++;
priv->stats.tx_bytes += skb->len;
return 0;
}
/*
* Deal with transmit timeouts coming from the network layer.
*/
static void
xpnet_dev_tx_timeout (struct net_device *dev)
{
struct xpnet_dev_private *priv;
priv = (struct xpnet_dev_private *) dev->priv;
priv->stats.tx_errors++;
return;
}
static int __init
xpnet_init(void)
{
int i;
u32 license_num;
int result = -ENOMEM;
if (!ia64_platform_is("sn2")) {
return -ENODEV;
}
dev_info(xpnet, "registering network device %s\n", XPNET_DEVICE_NAME);
/*
* use ether_setup() to init the majority of our device
* structure and then override the necessary pieces.
*/
xpnet_device = alloc_netdev(sizeof(struct xpnet_dev_private),
XPNET_DEVICE_NAME, ether_setup);
if (xpnet_device == NULL) {
return -ENOMEM;
}
netif_carrier_off(xpnet_device);
xpnet_device->mtu = XPNET_DEF_MTU;
xpnet_device->change_mtu = xpnet_dev_change_mtu;
xpnet_device->open = xpnet_dev_open;
xpnet_device->get_stats = xpnet_dev_get_stats;
xpnet_device->stop = xpnet_dev_stop;
xpnet_device->hard_start_xmit = xpnet_dev_hard_start_xmit;
xpnet_device->tx_timeout = xpnet_dev_tx_timeout;
xpnet_device->set_config = xpnet_dev_set_config;
/*
* 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.
*/
xpnet_device->dev_addr[0] = 0xfe;
xpnet_device->dev_addr[XPNET_PARTID_OCTET] = sn_partition_id;
license_num = sn_partition_serial_number_val();
for (i = 3; i >= 0; i--) {
xpnet_device->dev_addr[XPNET_LICENSE_OCTET + i] =
license_num & 0xff;
license_num = license_num >> 8;
}
/*
* 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_NO_CSUM;
result = register_netdev(xpnet_device);
if (result != 0) {
free_netdev(xpnet_device);
}
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);
}
module_exit(xpnet_exit);
MODULE_AUTHOR("Silicon Graphics, Inc.");
MODULE_DESCRIPTION("Cross Partition Network adapter (XPNET)");
MODULE_LICENSE("GPL");
