[IA64-SGI] SGI Altix cross partition functionality [3/3]

xp-y				:= xp_main.o xp_nofault.o

obj-$(CONFIG_IA64_SGI_SN_XP)	+= xpc.o

xpc-y				:= xpc_main.o xpc_channel.o xpc_partition.o

obj-$(CONFIG_IA64_SGI_SN_XP)	+= xpnet.o

/*

 * 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) 1999,2001-2005 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/config.h>

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/pci.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 <asm/sn/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 spinlock_t xpnet_broadcast_lock = SPIN_LOCK_UNLOCKED;

/*

 * 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 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);

		memcpy(skb->data, &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, (void *) skb->tail, (void *) skb->end,

		skb->len);

	skb->dev = xpnet_device;

	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, (void *) skb->tail,

		(void *) skb->end, 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, %d, "

		"%d)\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, (void *) skb->tail, (void *) skb->end,

		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);

	/* 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 promiscous 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);

			memcpy(&msg->data, skb->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;

		msg->buf_pa = __pa(start_addr);

		dev_dbg(xpnet, "sending XPC message to %d:%d\nmsg->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;

	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");