2009-09-11 Till Straumann <strauman@slac.stanford.edu>

	* Makefile.am, bsp.h, network/if_sim.c, network/README:
	added driver for NIC emulation.

5 files changed, 661 insertions, 0 deletions

diff --git a/c/src/lib/libbsp/powerpc/psim/ChangeLog b/c/src/lib/libbsp/powerpc/psim/ChangeLog
index 863cbf180d..9f17670985 100644
--- a/c/src/lib/libbsp/powerpc/psim/ChangeLog
+++ b/c/src/lib/libbsp/powerpc/psim/ChangeLog
@@ -1,5 +1,10 @@
 2009-09-11	Till Straumann <strauman@slac.stanford.edu>
 
+	* Makefile.am, bsp.h, network/if_sim.c, network/README:
+	added driver for NIC emulation.
+
+2009-09-11	Till Straumann <strauman@slac.stanford.edu>
+
 	* Makefile.am, preinstall.am, irq/no_pic.c (REMOVED),
 	irq/irq.h, irq/irq_init.c:
 	use openpic from 'shared' area instead of no_pic.
diff --git a/c/src/lib/libbsp/powerpc/psim/Makefile.am b/c/src/lib/libbsp/powerpc/psim/Makefile.am
index b2b97965d8..face282e53 100644
--- a/c/src/lib/libbsp/powerpc/psim/Makefile.am
+++ b/c/src/lib/libbsp/powerpc/psim/Makefile.am
@@ -69,6 +69,8 @@ libbsp_a_SOURCES += \
     shmsupp/addrconv.c shmsupp/getcfg.c shmsupp/lock.c shmsupp/mpisr.c
 endif
 
+libbsp_a_SOURCES += network/if_sim.c
+
 libbsp_a_LIBADD = ../../../libcpu/@RTEMS_CPU@/shared/cpuIdent.rel \
     ../../../libcpu/@RTEMS_CPU@/shared/stack.rel \
     ../../../libcpu/@RTEMS_CPU@/@exceptions@/rtems-cpu.rel \
diff --git a/c/src/lib/libbsp/powerpc/psim/include/bsp.h b/c/src/lib/libbsp/powerpc/psim/include/bsp.h
index 3960df6c9a..0add0ebd2c 100644
--- a/c/src/lib/libbsp/powerpc/psim/include/bsp.h
+++ b/c/src/lib/libbsp/powerpc/psim/include/bsp.h
@@ -67,6 +67,14 @@ extern uint32_t   BSP_mem_size;
 #define Processor_Synchronize() \
   asm(" eieio ")
 
+struct rtems_bsdnet_ifconfig;
+
+int
+rtems_ifsim_attach(struct rtems_bsdnet_ifconfig *ifcfg, int attaching);
+
+#define RTEMS_BSP_NETWORK_DRIVER_NAME   "ifsim1"
+#define RTEMS_BSP_NETWORK_DRIVER_ATTACH rtems_ifsim_attach
+
 #endif /* ASM */
 
 #define BSP_HAS_NO_VME
diff --git a/c/src/lib/libbsp/powerpc/psim/network/README b/c/src/lib/libbsp/powerpc/psim/network/README
new file mode 100644
index 0000000000..4ca287788c
--- /dev/null
+++ b/c/src/lib/libbsp/powerpc/psim/network/README
@@ -0,0 +1,141 @@
+PSIM NETWORKING HOWTO
+=====================
+
+IMPLEMENTATION INFORMATION
+
+1) NIC hardware emulation.
+
+   In order to simulate networking the simulator (PSIM in our case)
+   has to emulate some networking hardware.
+   At the time of this writing (2009/09 - gdb-6.8) no such emulation
+   is available.
+   However, a patch has been created which adds this functionality
+   to PSIM (see diff in this directory). Unfortunately, implementing
+   a network chip (or some other sort of 'data-source') in PSIM is
+   not quite that simple since PSIM is at the end of the day a single-
+   threaded, monolithic application which has no built-in support for
+   external asynchronous events (e.g., NIC packet reception or a
+   character arriving at a UART [the PSIM BSP uses a polled console
+   driver]).
+   In order to add such asynchronous support, the 'async_io' module
+   was added to PSIM. 'async_io' uses OS-support in the form of
+   a signal (SIGIO) that the OS sends to the PSIM process when I/O
+   becomes possible. The signal handler then executes a callback
+   which e.g., may schedule a PSIM interrupt.
+   However, the use of SIGIO and the O_ASYNC fcntl-flag is not portable
+   (BSD and linux only).
+   The 'ethtap' NIC emulation uses another not quite portable OS
+   service -- the host OS' TUN/TAP device which is some sort of
+   pipe with a networking-interface on one end and a file-system
+   interface on the other. The 'ethtap' NIC reads/writes packets
+   to the file-system interface and they then become available
+   to the host OS' networking.
+   This ascii-art shows how a RTEMS application inside PSIM can
+   communicate with an application on the host with both using
+   sockets. (If the host sets up proper routing table entries
+   then the RTEMS APP can even communicate with the internet...)
+
+
+      RTEMS APP                                       HOST APP
+          |                                               |
+     .............                                   ............
+     . <socket>  .                                   .<socket>  .
+     .RTEMS BSD  .                                   . HOST OS  .
+     .networking .                                   .networking.
+     .............                                   ............
+     
+   .......................                       .....................
+   .RTEMS BSD IF "ifsim1".                       . HOST OS IF: "tap0".
+   .e.g., 10.0.0.100     .                       . e.g., 10.0.0.1    .
+   .......................                       .....................
+                                                           o
+     .............                                         o
+     .RTEMS ifsim.                                         o
+     . driver    .                                         o
+     .............                                         o
+          ||                                               o
+          ||                                               o
+     ---------------                                       o
+       ethtap                                              o
+       hw emulation                                        o
+     ---------------                                       o
+           ^                                               o
+           |                                               o
+           -----> /dev/net/tun (special file on host OS) ooo
+                                                     
+                                                   
+2) Device-tree. Once PSIM supports the 'ethtap' device then it
+   must be added to the device tree. The following properties are
+   relevant (The register addresses must match with what the
+   BSP/if_sim expects):
+
+      #### ETHTAP @ 0x0c100020 for 0x40
+      #
+      
+      /ethtap@0x0c100020/reg           0x0c100020 0x40
+      # route interrupt to open-pic
+      /ethtap@0x0c100020               > 0 irq0 /opic@0x0c130000
+      # 'tun' device on host
+      /ethtap@0x0c100020/tun-device    "/dev/net/tun"
+      # name of 'tap' device to use
+      /ethtap@0x0c100020/tap-ifname    "tap0"
+      # ethernet address of simulated IF
+      /ethtap@0x0c100020/hw-address    "00:00:00:22:11:00"
+      # generate CRC and append to received packet before
+      # handing over to the simulation. This is mostly for
+      # debugging the rtems device driver. If unsure, leave 'false'.
+      /ethtap@0x0c100020/enable-crc    false
+
+   The 'tun-device' and 'tap-ifname' properties allow you to
+   configure the name of the special-file and the 'tap' interface
+   on the host.
+
+3) RTEMS driver. The 'if_sim' driver implements a driver for
+   the 'ethtap' device.
+
+USAGE INFORMATION
+
+1) Configure application for networking; the 
+     RTEMS_BSP_NETWORK_DRIVER_NAME   is "ifsim1"
+   and
+     RTEMS_BSP_NETWORK_DRIVER_ATTACH is rtems_ifsim_attach
+
+2) Patch, configure (--target=powerpc-rtems) and build
+   gdb-6.8. As already mentioned, the NIC emulation only
+   is available if your host-os is linux.
+
+3) Create a 'device-tree' file. The BSP build process produces
+   a shell-script 'psim' residing in
+
+      <bsp_installdir>/powerpc-rtems/psim/tests/
+
+   which can be used for generating a device-tree file.
+
+   Call 'psim -d -n <application>'. The '-n' option adds the
+   emulated interface (the lines above) to the device tree.
+   The resulting file is saved as <application>.device.
+
+   The 'psim' script can also be used to launch an application
+   directly -- just omit the '-d' option.
+
+4) Linux host network configuration:
+   Create a 'permanent' 'tap' interface. This allows you
+   to use 'psim' w/o special privileges (the 'tunctl' command
+   still must be executed by the super-user).
+
+      sudo tunctl -u <uid-of-user-running-psim>
+
+   You now can configure the 'tap0' interface:
+
+      sudo ifconfig tap0 10.0.0.1 up
+
+   and e.g., run a BOOTP server to provide RTEMS with its
+   network configuration:
+
+      sudo dhcpd3 -d tap0
+
+   Assuming that BOOTP gives the RTEMS guest an IP address
+   e.g., '10.0.0.100' you can 'ping' the RTEMS guest
+   from the linux host:
+
+      ping 10.0.0.100
diff --git a/c/src/lib/libbsp/powerpc/psim/network/if_sim.c b/c/src/lib/libbsp/powerpc/psim/network/if_sim.c
new file mode 100644
index 0000000000..58f35396fc
--- /dev/null
+++ b/c/src/lib/libbsp/powerpc/psim/network/if_sim.c
@@ -0,0 +1,505 @@
+/* $Id$ */
+
+/* Trivial driver for PSIM's emulated ethernet device 'hw_ethtap'.
+ *
+ * NOTE: At the time of this writing (2009/1) 'hw_ethtap' requires
+ *       a patched version of PSIM -- the vanilla version does not
+ *       implement this device.
+ *       Also, support for this device is currently only available
+ *       on a linux host.
+ *
+ * Author/Copyright: Till Straumann <Till.Straumann@TU-Berlin.de>
+ *
+ * LICENSE
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ */
+
+#include <bsp.h>
+#include <rtems.h>
+#include <bsp/irq.h>
+#include <psim.h>
+#include <libcpu/io.h>
+#include <inttypes.h>
+
+
+#ifndef KERNEL
+#define KERNEL
+#endif
+#ifndef _KERNEL
+#define _KERNEL
+#endif
+
+#include <rtems/rtems_bsdnet.h>
+#include <sys/mbuf.h>
+#include <sys/socket.h>
+#include <sys/sockio.h>
+#include <net/ethernet.h>
+#include <net/if.h>
+#include <netinet/in.h>
+#include <netinet/if_ether.h>
+
+#include <stdio.h>
+
+#define IFSIM_SLOTS 1
+
+#define DRVNAME "if_sim"
+
+#define IFSIM_TX_BUF_REG 1
+#define IFSIM_TX_STA_REG 2
+
+#define IFSIM_RX_BUF_REG 4
+#define IFSIM_RX_STA_REG 5
+
+#define IFSIM_RX_CNT_MSK  0xffff
+#define IFSIM_RX_STA_DONE (1<<31)
+
+#define IFSIM_RX_ERR_NOSPC	(1<<20)  /* buffer too small   */
+#define IFSIM_RX_ERR_DMA    (1<<21)  /* DMA error          */
+#define IFSIM_RX_ERR_RD     (1<<23)  /* file read error    */
+
+#define IFSIM_TX_STA_LST  (1<<16)
+#define IFSIM_TX_STA_DONE (1<<31)
+
+#define IFSIM_IEN_REG    6
+#define IFSIM_IRQ_REG    7
+
+#define IFSIM_RX_IRQ     (1<<0)
+
+#define IFSIM_MACA0_REG 8
+#define IFSIM_MACA1_REG 9
+
+#define IFSIM_CSR_REG  10
+#define IFSIM_CSR_PROM    (1<<0)
+/* Enable CRC generation/checking */
+#define IFSIM_CSR_CRCEN   (1<<1)
+
+
+#define RX_BUF_ALIGNMENT 1
+#define ETH_RX_OFFSET    0
+
+/*
+ * Align 'p' up to a multiple of 'a' which must be
+ * a power of two. Result is cast to (uintptr_t)
+ */
+#define ALIGNTO(p,a)    ((((uintptr_t)(p)) + (a) - 1) & ~((a)-1))
+
+
+typedef volatile unsigned reg_t;
+
+struct ifsim_private {
+	reg_t *base;
+	void  *rbuf;
+	unsigned rx_cserrs;
+	unsigned rx_err_nospc;
+	unsigned rx_err_dma;
+	unsigned rx_err_rd;
+	unsigned rx_nobufs;
+	unsigned rx_irqs;
+};
+
+struct ifsim_softc {
+	struct arpcom          arpcom;
+	struct ifsim_private   pvt;
+};
+
+struct ifsim_softc theIfSims[IFSIM_SLOTS] = {{{{0}}} };
+
+rtems_id           ifsim_tid = 0;
+
+__inline__ uint32_t
+ifsim_in(struct ifsim_softc *sc, unsigned regno)
+{
+	return in_be32( sc->pvt.base + regno );
+}
+
+__inline__ void
+ifsim_out(struct ifsim_softc *sc, unsigned regno, uint32_t v)
+{
+	out_be32(sc->pvt.base + regno, v);
+}
+
+static void *
+alloc_mbuf_rx(int *psz, uintptr_t *paddr)
+{
+struct mbuf     *m;
+unsigned long   l,o;
+
+    MGETHDR(m, M_DONTWAIT, MT_DATA);
+    if ( !m )
+        return 0;
+    MCLGET(m, M_DONTWAIT);
+    if ( ! (m->m_flags & M_EXT) ) {
+        m_freem(m);
+        return 0;
+    }
+
+    o = mtod(m, unsigned long);
+    l = ALIGNTO(o, RX_BUF_ALIGNMENT) - o;
+
+    /* align start of buffer */
+    m->m_data += l;
+
+    /* reduced length */
+    l = MCLBYTES - l;
+
+    m->m_len   = m->m_pkthdr.len = l;
+    *psz       = m->m_len;
+    *paddr     = mtod(m, unsigned long);
+
+    return (void*) m;
+}
+
+static int
+get_rxbuf(struct ifsim_softc *sc)
+{
+int         sz;
+uintptr_t   addr;
+void        *nbuf;
+
+	nbuf = alloc_mbuf_rx(&sz, &addr);
+
+	if ( nbuf ) {
+		sc->pvt.rbuf = nbuf;
+		ifsim_out(sc, IFSIM_RX_BUF_REG, addr);
+		ifsim_out(sc, IFSIM_RX_STA_REG, sz);
+		return 0;
+	}
+	return -1;
+}
+
+/* set/clear promiscuous mode */
+static void
+ifsim_upd_promisc(struct ifsim_softc *sc)
+{
+uint32_t ncsr, csr;
+
+	ncsr = csr = ifsim_in(sc, IFSIM_CSR_REG);
+
+	if ( sc->arpcom.ac_if.if_flags & IFF_PROMISC )
+		ncsr |=  IFSIM_CSR_PROM;
+	else
+		ncsr &= ~IFSIM_CSR_PROM;
+
+	if ( ncsr != csr )
+		ifsim_out(sc, IFSIM_CSR_REG, ncsr);
+}
+
+static void
+ifsim_init(void *arg)
+{
+struct ifsim_softc *sc = arg;
+struct ifnet       *ifp = &sc->arpcom.ac_if;
+
+	if ( 0 == get_rxbuf(sc) ) {
+		ifsim_upd_promisc(sc);
+		ifp->if_flags |= IFF_RUNNING;
+	}
+}
+
+static void
+ifsim_start(struct ifnet *ifp)
+{
+struct ifsim_softc *sc = ifp->if_softc;
+struct mbuf        *m, *mh, *m1;
+
+	while ( ifp->if_snd.ifq_head ) {
+		IF_DEQUEUE( &ifp->if_snd, mh );
+		for ( m=mh, m1 = m->m_next ; m1 ; m1 = m1->m_next ) {
+			ifsim_out(sc, IFSIM_TX_BUF_REG, mtod(m, uint32_t));
+			ifsim_out(sc, IFSIM_TX_STA_REG, m->m_len);
+			/* dummy-busywait; the emulated hardware DMAs our
+			 * data away 'immediately' i.e., this loop is
+			 * never executed
+			 */
+			while ( ! (IFSIM_TX_STA_DONE & ifsim_in(sc, IFSIM_TX_STA_REG)) )
+				/* Loop */;
+			m = m1;
+		}
+		ifsim_out(sc, IFSIM_TX_BUF_REG, mtod(m, uint32_t));
+		ifsim_out(sc, IFSIM_TX_STA_REG, m->m_len | IFSIM_TX_STA_LST);
+
+		/* dummy-busywait; the emulated hardware DMAs our
+		 * data away 'immediately' i.e., this loop is
+		 * never executed
+		 */
+		while ( ! (IFSIM_TX_STA_DONE & ifsim_in(sc, IFSIM_TX_STA_REG)) )
+			/* Loop */;
+
+		m_freem(mh);
+	}
+}
+
+static int
+ifsim_ioctl(struct ifnet *ifp, ioctl_command_t cmd, caddr_t data)
+{
+struct ifsim_softc *sc  = ifp->if_softc;
+int                rval = 0;
+int                f;
+
+	switch (cmd) {
+
+		case SIOCSIFFLAGS:
+			f = ifp->if_flags;
+			if ( f & IFF_UP ) {
+				if ( ! (f & IFF_RUNNING) ) {
+					ifsim_init(sc);
+				} else {
+					ifsim_upd_promisc(sc);
+				}
+				/* FIXME: handle other flags here */
+			} else {
+				if ( f & IFF_RUNNING ) {
+					printk("WARNING: bringing "DRVNAME" down not really implemented\n");
+					ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
+				}
+			}
+			
+		break;
+
+		case SIO_RTEMS_SHOW_STATS:
+			printf("RX bad chksum  : %u\n", sc->pvt.rx_cserrs);
+			printf("RX no space    : %u\n", sc->pvt.rx_err_nospc);
+			printf("RX bad DMA     : %u\n", sc->pvt.rx_err_dma);
+			printf("RX read errors : %u\n", sc->pvt.rx_err_rd);
+			printf("rx_nobufs      : %u\n", sc->pvt.rx_nobufs);
+			printf("rx_irqs        : %u\n", sc->pvt.rx_irqs);
+		break;
+
+		default:
+			rval = ether_ioctl(ifp, cmd, data);
+		break;
+	}
+
+	return rval;
+}
+
+static void ifsim_irq_on(const rtems_irq_connect_data *pd)
+{
+struct ifsim_softc *sc = pd->handle;
+	ifsim_out(sc, IFSIM_IEN_REG, IFSIM_RX_IRQ);
+}
+
+static void ifsim_irq_off(const rtems_irq_connect_data *pd)
+{
+struct ifsim_softc *sc = pd->handle;
+	ifsim_out(sc, IFSIM_IEN_REG, 0);
+}
+
+static int ifsim_irq_ison(const rtems_irq_connect_data *pd)
+{
+struct ifsim_softc *sc = pd->handle;
+	return ifsim_in(sc, IFSIM_IEN_REG) & IFSIM_RX_IRQ ? 1 : 0;
+}
+
+static void
+ifsim_isr(void *arg)
+{
+struct ifsim_softc *sc = arg;
+
+	sc->pvt.rx_irqs++;
+#ifdef IRQ_DEBUG
+	printk("ISR happened\n");
+#endif
+
+	ifsim_out(sc, IFSIM_IEN_REG, 0);
+	rtems_event_send(ifsim_tid, (1<<(sc-theIfSims)));
+}
+
+static void
+ifsim_task(void *arg)
+{
+struct ifsim_softc *sc;
+uint32_t           sta;
+struct ifnet       *ifp;
+unsigned           len;
+rtems_event_set    evs;
+
+	while (1) {
+
+		rtems_bsdnet_event_receive(
+			((1<<IFSIM_SLOTS)-1),
+			RTEMS_WAIT | RTEMS_EVENT_ANY,
+			RTEMS_NO_TIMEOUT,
+			&evs);
+
+		evs &= ((1<<IFSIM_SLOTS)-1);
+
+#ifdef IRQ_DEBUG
+		printf("Task got evs %u\n", evs);
+#endif
+
+		for ( sc = theIfSims; evs; evs>>=1, sc++ ) {
+
+			if ( ! ( evs & 1 ) )
+				continue;
+
+			ifp = &sc->arpcom.ac_if;
+
+			while ( ifsim_in(sc, IFSIM_IRQ_REG) & IFSIM_RX_IRQ ) {
+				struct mbuf *m = sc->pvt.rbuf;
+
+				sta = ifsim_in(sc, IFSIM_RX_STA_REG);
+
+
+				if ( (sta & IFSIM_RX_STA_DONE) ) {
+
+					if ( (ifp->if_flags & IFF_RUNNING) ) {
+						if ( 0 == get_rxbuf(sc) ) {
+							/* enqueue packet */
+							struct ether_header *eh;
+							uint32_t            crc_net, crc;
+							int                 crc_len;
+
+							crc_len = (IFSIM_CSR_CRCEN & ifsim_in(sc, IFSIM_CSR_REG)) ? sizeof(crc_net) : 0;
+
+							len = (sta & IFSIM_RX_CNT_MSK) - crc_len;
+
+							eh = (struct ether_header*)(mtod(m,unsigned long) + ETH_RX_OFFSET);
+
+							m->m_len = m->m_pkthdr.len = len - sizeof(struct ether_header) - ETH_RX_OFFSET;
+							m->m_data += sizeof(struct ether_header) + ETH_RX_OFFSET;
+							m->m_pkthdr.rcvif = ifp;
+
+#ifdef DEBUG_WO_BSDNET
+							{
+								int i;
+								for ( i=0; i<len + crc_len; ) {
+									printf("%02X ",((char*)eh)[i]);
+									if ( 0 == (++i & 0xf) )
+										fputc('\n',stdout);
+								}
+								if ( i & 0xf )
+									fputc('\n', stdout);
+								printf("*****\n");
+							}
+#endif
+
+							if ( crc_len
+								 && (memcpy(&crc_net, (char*)eh + len, crc_len),
+							        (crc = (ether_crc32_le((uint8_t *)eh, len) ^ 0xffffffff)) != crc_net) ) {
+								printk("CSUM: me 0x%08X, them 0x%08x\n", crc, crc_net);
+								sc->pvt.rx_cserrs++;
+							} else {
+
+								ifp->if_ipackets++;
+								ifp->if_ibytes  += len;
+
+#ifdef DEBUG_WO_BSDNET
+								m_freem(m);
+#else
+								ether_input(ifp, eh, m);
+#endif
+
+								m = 0;
+							}
+
+						} else {
+							/* throw away and reuse buffer */
+							sc->pvt.rx_nobufs++;
+						}
+					}
+				} else {
+					/* throw away and reuse buffer */
+					if ( (sta & IFSIM_RX_ERR_NOSPC) )
+						sc->pvt.rx_err_nospc++;
+					if ( (sta & IFSIM_RX_ERR_DMA) )
+						sc->pvt.rx_err_dma++;
+					if ( (sta & IFSIM_RX_ERR_RD) )
+						sc->pvt.rx_err_rd++;
+				}
+
+				if ( m ) {
+					/* reuse */
+					ifsim_out(sc, IFSIM_RX_STA_REG, m->m_pkthdr.len);
+				}
+			}
+			/* re-enable interrupt */
+			ifsim_out(sc, IFSIM_IEN_REG, IFSIM_RX_IRQ);
+		}
+	}
+}
+
+int
+rtems_ifsim_attach(struct rtems_bsdnet_ifconfig *ifcfg, int attaching)
+{
+char                   *unitName;
+int                    unit;
+struct ifsim_softc     *sc;
+struct ifnet           *ifp;
+uint32_t               v;
+rtems_irq_connect_data ihdl;
+
+	if ( !attaching )
+		return -1;
+
+	unit = rtems_bsdnet_parse_driver_name(ifcfg, &unitName);
+
+	if ( unit <= 0 || unit > IFSIM_SLOTS ) {
+		printk(DRVNAME": Bad unit number %i; must be 1..%i\n", unit, IFSIM_SLOTS);
+		return 1;
+	}
+
+	sc  = &theIfSims[unit-1];
+	ifp = &sc->arpcom.ac_if;
+
+	memset(&sc->pvt, 0, sizeof(sc->pvt));
+
+	sc->pvt.base = (reg_t*)ifcfg->port;
+
+	if ( 0 == sc->pvt.base )
+		sc->pvt.base = (reg_t*)PSIM.Ethtap;
+
+
+	sc->pvt.rbuf = 0;
+
+	if ( !ifsim_tid ) {
+		ifsim_tid = rtems_bsdnet_newproc("IFSM", 10000, ifsim_task, 0);
+	}
+
+	ihdl.name   = ifcfg->irno;
+	ihdl.hdl    = ifsim_isr;
+	ihdl.handle = sc; 
+	ihdl.on     = ifsim_irq_on;
+	ihdl.off    = ifsim_irq_off;
+	ihdl.isOn   = ifsim_irq_ison;
+
+	if ( ! BSP_install_rtems_irq_handler(&ihdl) ) {
+		printk(DRVNAME"_attach(): installing ISR failed!\n");
+		return -1;
+	}
+
+	if ( ifcfg->hardware_address ) {
+		memcpy(sc->arpcom.ac_enaddr, ifcfg->hardware_address, ETHER_ADDR_LEN);
+	} else {
+		v = ifsim_in(sc, IFSIM_MACA0_REG);
+		memcpy(sc->arpcom.ac_enaddr, &v, 4);
+		v = ifsim_in(sc, IFSIM_MACA1_REG);
+		memcpy(sc->arpcom.ac_enaddr+4, &v, 2);
+	}
+
+	ifp->if_softc     = sc;
+	ifp->if_unit      = unit;
+	ifp->if_name      = unitName;
+
+	ifp->if_mtu       = ifcfg->mtu ? ifcfg->mtu : ETHERMTU;
+
+	ifp->if_init      = ifsim_init;
+	ifp->if_ioctl     = ifsim_ioctl;
+	ifp->if_start     = ifsim_start;
+	ifp->if_output    = ether_output;
+
+	ifp->if_watchdog  = 0;
+	ifp->if_timer     = 0;
+
+	ifp->if_flags     = IFF_BROADCAST | IFF_SIMPLEX;
+
+	ifp->if_snd.ifq_maxlen = ifqmaxlen;
+
+	if_attach(ifp);
+	ether_ifattach(ifp);
+
+	return 0;
+}