linux-imx

/*

 * 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) 1999-2009 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.