[unix-history] / usr / src / sys / vax / if / if_css.c

/*      if_css.c     4.2     82/10/09     */

#include "css.h"

/*
 * DEC/CSS IMP11-A ARPAnet IMP interface driver.
 * Since "imp11a" is such a mouthful, it is called
 * "css" after the LH/DH being called "acc".
 *
 * Configuration notes:
 *
 * As delivered from DEC/CSS, it
 * is addressed and vectored as two DR11-B's.  This makes
 * Autoconfig almost IMPOSSIBLE.  To make it work, the
 * interrupt vectors must be restrapped to make the vectors
 * consecutive.  The 020 hole between the CSR addresses is
 * tolerated, althought that could be cleaned-up also.
 *
 * Additionally, the TRANSMIT side of the IMP11-A has the
 * lower address of the two subunits, so the vector ordering
 * in the CONFIG file is reversed from most other devices.
 * It should be:
 *
 * device css0 ....  cssxint cssrint
 *
 * If you get it wrong, it will still autoconfig, but will just
 * sit there with RECIEVE IDLE indicated on the front panel.
 */

#include "../h/param.h"
#include "../h/systm.h"
#include "../h/mbuf.h"
#include "../h/pte.h"
#include "../h/buf.h"
#include "../h/protosw.h"
#include "../h/socket.h"
#include "../h/ubareg.h"
#include "../h/ubavar.h"
#include "../h/cpu.h"
#include "../h/mtpr.h"
#include "../h/vmmac.h"
#include "../vaxif/if_css.h"
#include "../net/if.h"
#include "../netimp/if_imp.h"
#include "../vaxif/if_uba.h"

int     cssprobe(), cssattach(), cssrint(), cssxint();
struct  uba_device *cssinfo[NCSS];
u_short cssstd[] = { 0 };
struct  uba_driver cssdriver =
        { cssprobe, 0, cssattach, 0, cssstd, "css", cssinfo };
#define CSSUNIT(x)      minor(x)

int     cssinit(), cssstart(), cssreset();

/*
 * "Lower half" of IMP interface driver.
 *
 * Each IMP interface is handled by a common module which handles
 * the IMP-host protocol and a hardware driver which manages the
 * hardware specific details of talking with the IMP.
 *
 * The hardware portion of the IMP driver handles DMA and related
 * management of UNIBUS resources.  The IMP protocol module interprets
 * contents of these messages and "controls" the actions of the
 * hardware module during IMP resets, but not, for instance, during
 * UNIBUS resets.
 *
 * The two modules are coupled at "attach time", and ever after,
 * through the imp interface structure.  Higher level protocols,
 * e.g. IP, interact with the IMP driver, rather than the CSS.
 */
struct  css_softc {
        struct  ifnet *css_if;          /* pointer to IMP's ifnet struct */
        struct  impcb *css_ic;          /* data structure shared with IMP */
        struct  ifuba css_ifuba;        /* UNIBUS resources */
        struct  mbuf *css_iq;           /* input reassembly queue */
        short   css_olen;               /* size of last message sent */
        char    css_flush;              /* flush remainder of message */
} css_softc[NCSS];

/*
 * Reset the IMP and cause a transmitter interrupt by
 * performing a null DMA.
 */
cssprobe(reg)
        caddr_t reg;
{
        register int br, cvec;          /* r11, r10 value-result */
        register struct cssdevice *addr = (struct cssdevice *)reg;

COUNT(CSSPROBE);
#ifdef lint
        br = 0; cvec = br; br = cvec;
        cssrint(0); cssxint(0);
#endif


        addr->css_icsr = CSS_CLR;
        addr->css_ocsr = CSS_CLR;
        DELAY(50000);
	addr->css_icsr = 0;
	addr->css_ocsr = 0;
        DELAY(50000);

	addr->css_oba = 0;
	addr->css_owc = -1;
        addr->css_ocsr = CSS_IE | CSS_GO;	/* enable interrupts */
        DELAY(50000);
        addr->css_ocsr = 0;

        return (1);
}

/*
 * Call the IMP module to allow it to set up its internal
 * state, then tie the two modules together by setting up
 * the back pointers to common data structures.
 */
cssattach(ui)
        struct uba_device *ui;
{
        register struct css_softc *sc = &css_softc[ui->ui_unit];
        register struct impcb *ip;
        struct ifimpcb {
                struct  ifnet ifimp_if;
                struct  impcb ifimp_impcb;
        } *ifimp;

COUNT(CSSATTACH);
        if ((ifimp = (struct ifimpcb *)impattach(ui)) == 0)
                panic("cssattach");             /* XXX */
        sc->css_if = &ifimp->ifimp_if;
        ip = &ifimp->ifimp_impcb;
        sc->css_ic = ip;
        ip->ic_init = cssinit;
        ip->ic_start = cssstart;
	sc->css_ifuba.ifu_flags = UBA_CANTWAIT | UBA_NEED16;
#ifdef notdef
	sc->css_ifuba.ifu_flags =| UBA_NEEDBDP;
#endif
}

/*
 * Reset interface after UNIBUS reset.
 * If interface is on specified uba, reset its state.
 */
cssreset(unit, uban)
        int unit, uban;
{
        register struct uba_device *ui;
        struct css_softc *sc;

COUNT(CSSCLR);
        if (unit >= NCSS || (ui = cssinfo[unit]) == 0 || ui->ui_alive == 0 ||
            ui->ui_ubanum != uban)
                return;
        printf(" css%d", unit);
        sc = &css_softc[unit];
        /* must go through IMP to allow it to set state */
        (*sc->css_if->if_init)(unit);
}

/*
 * Initialize interface: clear recorded pending operations,
 * and retrieve, and reinitialize UNIBUS resources.
 */
cssinit(unit)
        int unit;
{       
        register struct css_softc *sc;
        register struct uba_device *ui;
        register struct cssdevice *addr;
        int x, info;

COUNT(CSSINIT);
	if (unit >= NCSS || (ui = cssinfo[unit]) == 0 || ui->ui_alive == 0) {
		printf("css%d: not alive\n", unit);
		return(0);
	}
	sc = &css_softc[unit];

	/*
	 * Header length is 0 to if_ubainit since we have to pass
	 * the IMP leader up to the protocol interpretaion
	 * routines.  If we had the deader length as
	 * sizeof(struct imp_leader), then the if_ routines
	 * would assume we handle it on input and output.
	 */
	
        if (if_ubainit(&sc->css_ifuba, ui->ui_ubanum, 0,(int)btoc(IMPMTU)) == 0) {
                printf("css%d: can't initialize\n", unit);
		ui->ui_alive = 0;
		return(0);
        }
        addr = (struct cssdevice *)ui->ui_addr;

        /* reset the imp interface. */
        x = spl5();
        addr->css_icsr = CSS_CLR;
        addr->css_ocsr = CSS_CLR;
	DELAY(100);
	addr->css_icsr = 0;
	addr->css_ocsr = 0;
        addr->css_icsr = IN_HRDY;       /* close the relay */
	DELAY(5000);
        splx(x);

        /*
	 * This may hang if the imp isn't really there.
	 * Will test and verify safe operation.
	 */

	x = 500;
	while (x-- > 0) {
		if ((addr->css_icsr & (IN_HRDY|IN_IMPNR)) == IN_HRDY) 
			break;
                addr->css_icsr = IN_HRDY;	/* close the relay */
                DELAY(5000);
        }

	if (x <= 0) {
		printf("css%d: imp doesn't respond, icsr=%b\n", unit,
			CSS_INBITS, addr->css_icsr);
		goto down;
	}

        /*
         * Put up a read.  We can't restart any outstanding writes
         * until we're back in synch with the IMP (i.e. we've flushed
         * the NOOPs it throws at us).
	 * Note: IMPMTU includes the leader.
         */

        x = spl5();
        info = sc->css_ifuba.ifu_r.ifrw_info;
        addr->css_iba = (u_short)info;
        addr->css_iwc = -(IMPMTU >> 1);
        addr->css_icsr = 
                IN_HRDY | CSS_IE | IN_WEN | ((info & 0x30000) >> 12) | CSS_GO;
        splx(x);
	return(1);

down:
	ui->ui_alive = 0;
	return(0);
}

/*
 * Start output on an interface.
 */
cssstart(dev)
        dev_t dev;
{
        int unit = CSSUNIT(dev), info;
        struct uba_device *ui = cssinfo[unit];
        register struct css_softc *sc = &css_softc[unit];
        register struct cssdevice *addr;
        struct mbuf *m;
        u_short cmd;

COUNT(CSSSTART);
        if (sc->css_ic->ic_oactive)
                goto restart;
        
        /*
         * Not already active, deqeue a request and
         * map it onto the UNIBUS.  If no more
         * requeusts, just return.
         */
        IF_DEQUEUE(&sc->css_if->if_snd, m);
        if (m == 0) {
                sc->css_ic->ic_oactive = 0;
                return;
        }
        sc->css_olen = if_wubaput(&sc->css_ifuba, m);

restart:
        /*
         * Have request mapped to UNIBUS for transmission.
         * Purge any stale data from the BDP, and start the output.
         */
	if (sc->css_ifuba.ifu_flags & UBA_NEEDBDP)
		UBAPURGE(sc->css_ifuba.ifu_uba, sc->css_ifuba.ifu_w.ifrw_bdp);
        addr = (struct cssdevice *)ui->ui_addr;
        info = sc->css_ifuba.ifu_w.ifrw_info;
        addr->css_oba = (u_short)info;
        addr->css_owc = -((sc->css_olen + 1) >> 1);
        cmd = CSS_IE | OUT_ENLB | ((info & 0x30000) >> 12) | CSS_GO;
        addr->css_ocsr = cmd;
        sc->css_ic->ic_oactive = 1;
}

/*
 * Output interrupt handler.
 */
cssxint(unit)
{
        register struct uba_device *ui = cssinfo[unit];
        register struct css_softc *sc = &css_softc[unit];
        register struct cssdevice *addr;

COUNT(CSSXINT);
        addr = (struct cssdevice *)ui->ui_addr;
        if (sc->css_ic->ic_oactive == 0) {
                printf("css%d: stray output interrupt csr=%b\n",
			unit, addr->css_ocsr, CSS_OUTBITS);
                return;
        }
        sc->css_if->if_opackets++;
        sc->css_ic->ic_oactive = 0;
        if (addr->css_ocsr & CSS_ERR){
                sc->css_if->if_oerrors++;
                printf("css%d: output error, ocsr=%b icsr=%b\n", unit,
                        addr->css_ocsr, CSS_OUTBITS,
			addr->css_icsr, CSS_INBITS);
	}
	if (sc->css_ifuba.ifu_xtofree) {
		m_freem(sc->css_ifuba.ifu_xtofree);
		sc->css_ifuba.ifu_xtofree = 0;
	}
	if (sc->css_if->if_snd.ifq_head)
		cssstart(unit);
}

/*
 * Input interrupt handler
 */
cssrint(unit)
{
        register struct css_softc *sc = &css_softc[unit];
        register struct cssdevice *addr;
        register struct ifqueue *inq;
        struct mbuf *m;
        int len, info;

COUNT(CSSRINT);
        sc->css_if->if_ipackets++;

        /*
         * Purge BDP; flush message if error indicated.
         */

        addr = (struct cssdevice *)cssinfo[unit]->ui_addr;
	if (sc->css_ifuba.ifu_flags & UBA_NEEDBDP)
		UBAPURGE(sc->css_ifuba.ifu_uba, sc->css_ifuba.ifu_r.ifrw_bdp);
        if (addr->css_icsr & CSS_ERR) {
                printf("css%d: recv error, csr=%b\n", unit,
                    addr->css_icsr, CSS_INBITS);
                sc->css_if->if_ierrors++;
                sc->css_flush = 1;
        }

        if (sc->css_flush) {
                if (addr->css_icsr & IN_EOM)
                        sc->css_flush = 0;
                goto setup;
        }

        len = IMPMTU + (addr->css_iwc << 1);
	if (len < 0 || len > IMPMTU) {
		printf("css%d: bad length=%d\n", len);
		sc->css_if->if_ierrors++;
		goto setup;
	}

        /*
         * The last parameter is always 0 since using
         * trailers on the ARPAnet is insane.
         */
        m = if_rubaget(&sc->css_ifuba, len, 0);
        if (m == 0)
                goto setup;
        if ((addr->css_icsr & IN_EOM) == 0) {
		if (sc->css_iq)
			m_cat(sc->css_iq, m);
		else
			sc->css_iq = m;
		goto setup;
	}
	if (sc->css_iq) {
		m_cat(sc->css_iq, m);
		m = sc->css_iq;
		sc->css_iq = 0;
        }
        impinput(unit, m);

setup:
        /*
         * Setup for next message.
         */
        info = sc->css_ifuba.ifu_r.ifrw_info;
        addr->css_iba = (u_short)info;
        addr->css_iwc = - (IMPMTU >> 1);
        addr->css_icsr =
                IN_HRDY | CSS_IE | IN_WEN | ((info & 0x30000) >> 12) | CSS_GO;
}
Commit	Line	Data
d2cc167c	1	/* if_css.c 4.2 82/10/09 */
ee6d9923 SL	2
	3	#include "css.h"
	4
	5	/*
	6	* DEC/CSS IMP11-A ARPAnet IMP interface driver.
	7	* Since "imp11a" is such a mouthful, it is called
	8	* "css" after the LH/DH being called "acc".
	9	*
	10	* Configuration notes:
	11	*
	12	* As delivered from DEC/CSS, it
	13	* is addressed and vectored as two DR11-B's. This makes
	14	* Autoconfig almost IMPOSSIBLE. To make it work, the
	15	* interrupt vectors must be restrapped to make the vectors
	16	* consecutive. The 020 hole between the CSR addresses is
	17	* tolerated, althought that could be cleaned-up also.
	18	*
	19	* Additionally, the TRANSMIT side of the IMP11-A has the
	20	* lower address of the two subunits, so the vector ordering
	21	* in the CONFIG file is reversed from most other devices.
	22	* It should be:
	23	*
	24	* device css0 .... cssxint cssrint
	25	*
	26	* If you get it wrong, it will still autoconfig, but will just
	27	* sit there with RECIEVE IDLE indicated on the front panel.
	28	*/
	29
	30	#include "../h/param.h"
	31	#include "../h/systm.h"
	32	#include "../h/mbuf.h"
	33	#include "../h/pte.h"
	34	#include "../h/buf.h"
	35	#include "../h/protosw.h"
	36	#include "../h/socket.h"
	37	#include "../h/ubareg.h"
	38	#include "../h/ubavar.h"
	39	#include "../h/cpu.h"
	40	#include "../h/mtpr.h"
	41	#include "../h/vmmac.h"
d2cc167c	42	#include "../vaxif/if_css.h"
ee6d9923	43	#include "../net/if.h"
d2cc167c BJ	44	#include "../netimp/if_imp.h"
d2cc167c BJ	45	#include "../vaxif/if_uba.h"
ee6d9923 SL	46
	47	int cssprobe(), cssattach(), cssrint(), cssxint();
	48	struct uba_device *cssinfo[NCSS];
	49	u_short cssstd[] = { 0 };
	50	struct uba_driver cssdriver =
	51	{ cssprobe, 0, cssattach, 0, cssstd, "css", cssinfo };
	52	#define CSSUNIT(x) minor(x)
	53
	54	int cssinit(), cssstart(), cssreset();
	55
	56	/*
	57	* "Lower half" of IMP interface driver.
	58	*
	59	* Each IMP interface is handled by a common module which handles
	60	* the IMP-host protocol and a hardware driver which manages the
	61	* hardware specific details of talking with the IMP.
	62	*
	63	* The hardware portion of the IMP driver handles DMA and related
	64	* management of UNIBUS resources. The IMP protocol module interprets
	65	* contents of these messages and "controls" the actions of the
	66	* hardware module during IMP resets, but not, for instance, during
	67	* UNIBUS resets.
	68	*
	69	* The two modules are coupled at "attach time", and ever after,
	70	* through the imp interface structure. Higher level protocols,
	71	* e.g. IP, interact with the IMP driver, rather than the CSS.
	72	*/
	73	struct css_softc {
	74	struct ifnet css_if; / pointer to IMP's ifnet struct */
	75	struct impcb css_ic; / data structure shared with IMP */
	76	struct ifuba css_ifuba; /* UNIBUS resources */
	77	struct mbuf css_iq; / input reassembly queue */
	78	short css_olen; /* size of last message sent */
	79	char css_flush; /* flush remainder of message */
	80	} css_softc[NCSS];
	81
	82	/*
	83	* Reset the IMP and cause a transmitter interrupt by
	84	* performing a null DMA.
	85	*/
	86	cssprobe(reg)
	87	caddr_t reg;
	88	{
	89	register int br, cvec; /* r11, r10 value-result */
	90	register struct cssdevice addr = (struct cssdevice )reg;
	91
	92	COUNT(CSSPROBE);
	93	#ifdef lint
	94	br = 0; cvec = br; br = cvec;
	95	cssrint(0); cssxint(0);
	96	#endif
	97
	98
	99	addr->css_icsr = CSS_CLR;
	100	addr->css_ocsr = CSS_CLR;
	101	DELAY(50000);
	102	addr->css_icsr = 0;
	103	addr->css_ocsr = 0;
	104	DELAY(50000);
	105
	106	addr->css_oba = 0;
	107	addr->css_owc = -1;
	108	addr->css_ocsr = CSS_IE \| CSS_GO; /* enable interrupts */
	109	DELAY(50000);
110	addr->css_ocsr = 0;
111
112	return (1);
113	}
114
115	/*
116	* Call the IMP module to allow it to set up its internal
117	* state, then tie the two modules together by setting up
118	* the back pointers to common data structures.
119	*/
120	cssattach(ui)
121	struct uba_device *ui;
122	{
123	register struct css_softc *sc = &css_softc[ui->ui_unit];
124	register struct impcb *ip;
125	struct ifimpcb {
126	struct ifnet ifimp_if;
127	struct impcb ifimp_impcb;
128	} *ifimp;
129
130	COUNT(CSSATTACH);
131	if ((ifimp = (struct ifimpcb *)impattach(ui)) == 0)
132	panic("cssattach"); /* XXX */
133	sc->css_if = &ifimp->ifimp_if;
134	ip = &ifimp->ifimp_impcb;
135	sc->css_ic = ip;
136	ip->ic_init = cssinit;
137	ip->ic_start = cssstart;
138	sc->css_ifuba.ifu_flags = UBA_CANTWAIT \| UBA_NEED16;
139	#ifdef notdef
140	sc->css_ifuba.ifu_flags =\| UBA_NEEDBDP;
141	#endif
142	}
143
144	/*
145	* Reset interface after UNIBUS reset.
146	* If interface is on specified uba, reset its state.
147	*/
148	cssreset(unit, uban)
149	int unit, uban;
150	{
151	register struct uba_device *ui;
152	struct css_softc *sc;
153
154	COUNT(CSSCLR);
155	if (unit >= NCSS \|\| (ui = cssinfo[unit]) == 0 \|\| ui->ui_alive == 0 \|\|
156	ui->ui_ubanum != uban)
157	return;
158	printf(" css%d", unit);
159	sc = &css_softc[unit];
160	/* must go through IMP to allow it to set state */
161	(*sc->css_if->if_init)(unit);
162	}
163
164	/*
165	* Initialize interface: clear recorded pending operations,
166	* and retrieve, and reinitialize UNIBUS resources.
167	*/
168	cssinit(unit)
169	int unit;
170	{
171	register struct css_softc *sc;
172	register struct uba_device *ui;
173	register struct cssdevice *addr;
174	int x, info;
175
176	COUNT(CSSINIT);
177	if (unit >= NCSS \|\| (ui = cssinfo[unit]) == 0 \|\| ui->ui_alive == 0) {
178	printf("css%d: not alive\n", unit);
179	return(0);
180	}
181	sc = &css_softc[unit];
182
183	/*
184	* Header length is 0 to if_ubainit since we have to pass
185	* the IMP leader up to the protocol interpretaion
186	* routines. If we had the deader length as
187	* sizeof(struct imp_leader), then the if_ routines
188	* would assume we handle it on input and output.
189	*/
190
191	if (if_ubainit(&sc->css_ifuba, ui->ui_ubanum, 0,(int)btoc(IMPMTU)) == 0) {
192	printf("css%d: can't initialize\n", unit);
193	ui->ui_alive = 0;
194	return(0);
195	}
196	addr = (struct cssdevice *)ui->ui_addr;
197
198	/* reset the imp interface. */
199	x = spl5();
200	addr->css_icsr = CSS_CLR;
201	addr->css_ocsr = CSS_CLR;
202	DELAY(100);
203	addr->css_icsr = 0;
204	addr->css_ocsr = 0;
205	addr->css_icsr = IN_HRDY; /* close the relay */
206	DELAY(5000);
207	splx(x);
208
209	/*
210	* This may hang if the imp isn't really there.
211	* Will test and verify safe operation.
212	*/
213
214	x = 500;
215	while (x-- > 0) {
216	if ((addr->css_icsr & (IN_HRDY\|IN_IMPNR)) == IN_HRDY)
217	break;
218	addr->css_icsr = IN_HRDY; /* close the relay */
219	DELAY(5000);
220	}
221
222	if (x <= 0) {
223	printf("css%d: imp doesn't respond, icsr=%b\n", unit,
224	CSS_INBITS, addr->css_icsr);
225	goto down;
226	}
227
228	/*
229	* Put up a read. We can't restart any outstanding writes
230	* until we're back in synch with the IMP (i.e. we've flushed
231	* the NOOPs it throws at us).
232	* Note: IMPMTU includes the leader.
233	*/
234
235	x = spl5();
236	info = sc->css_ifuba.ifu_r.ifrw_info;
237	addr->css_iba = (u_short)info;
238	addr->css_iwc = -(IMPMTU >> 1);
239	addr->css_icsr =
240	IN_HRDY \| CSS_IE \| IN_WEN \| ((info & 0x30000) >> 12) \| CSS_GO;
241	splx(x);
242	return(1);
243
244	down:
245	ui->ui_alive = 0;
246	return(0);
247	}
248
249	/*
250	* Start output on an interface.
251	*/
252	cssstart(dev)
253	dev_t dev;
254	{
255	int unit = CSSUNIT(dev), info;
256	struct uba_device *ui = cssinfo[unit];
257	register struct css_softc *sc = &css_softc[unit];
258	register struct cssdevice *addr;
259	struct mbuf *m;
260	u_short cmd;
261
262	COUNT(CSSSTART);
263	if (sc->css_ic->ic_oactive)
264	goto restart;
265
266	/*
267	* Not already active, deqeue a request and
268	* map it onto the UNIBUS. If no more
269	* requeusts, just return.
270	*/
271	IF_DEQUEUE(&sc->css_if->if_snd, m);
272	if (m == 0) {
273	sc->css_ic->ic_oactive = 0;
274	return;
275	}
276	sc->css_olen = if_wubaput(&sc->css_ifuba, m);
277
278	restart:
279	/*
280	* Have request mapped to UNIBUS for transmission.
281	* Purge any stale data from the BDP, and start the output.
282	*/
283	if (sc->css_ifuba.ifu_flags & UBA_NEEDBDP)
284	UBAPURGE(sc->css_ifuba.ifu_uba, sc->css_ifuba.ifu_w.ifrw_bdp);
285	addr = (struct cssdevice *)ui->ui_addr;
286	info = sc->css_ifuba.ifu_w.ifrw_info;
287	addr->css_oba = (u_short)info;
288	addr->css_owc = -((sc->css_olen + 1) >> 1);
289	cmd = CSS_IE \| OUT_ENLB \| ((info & 0x30000) >> 12) \| CSS_GO;
290	addr->css_ocsr = cmd;
291	sc->css_ic->ic_oactive = 1;
292	}
293
294	/*
295	* Output interrupt handler.
296	*/
297	cssxint(unit)
298	{
299	register struct uba_device *ui = cssinfo[unit];
300	register struct css_softc *sc = &css_softc[unit];
301	register struct cssdevice *addr;
302
303	COUNT(CSSXINT);
304	addr = (struct cssdevice *)ui->ui_addr;
305	if (sc->css_ic->ic_oactive == 0) {
306	printf("css%d: stray output interrupt csr=%b\n",
307	unit, addr->css_ocsr, CSS_OUTBITS);
308	return;
309	}
310	sc->css_if->if_opackets++;
311	sc->css_ic->ic_oactive = 0;
312	if (addr->css_ocsr & CSS_ERR){
313	sc->css_if->if_oerrors++;
314	printf("css%d: output error, ocsr=%b icsr=%b\n", unit,
315	addr->css_ocsr, CSS_OUTBITS,
316	addr->css_icsr, CSS_INBITS);
317	}
318	if (sc->css_ifuba.ifu_xtofree) {
319	m_freem(sc->css_ifuba.ifu_xtofree);
320	sc->css_ifuba.ifu_xtofree = 0;
321	}
322	if (sc->css_if->if_snd.ifq_head)
323	cssstart(unit);
324	}
325
326	/*
327	* Input interrupt handler
328	*/
329	cssrint(unit)
330	{
331	register struct css_softc *sc = &css_softc[unit];
332	register struct cssdevice *addr;
333	register struct ifqueue *inq;
334	struct mbuf *m;
335	int len, info;
336
337	COUNT(CSSRINT);
338	sc->css_if->if_ipackets++;
339
340	/*
341	* Purge BDP; flush message if error indicated.
342	*/
343
344	addr = (struct cssdevice *)cssinfo[unit]->ui_addr;
345	if (sc->css_ifuba.ifu_flags & UBA_NEEDBDP)
346	UBAPURGE(sc->css_ifuba.ifu_uba, sc->css_ifuba.ifu_r.ifrw_bdp);
347	if (addr->css_icsr & CSS_ERR) {
348	printf("css%d: recv error, csr=%b\n", unit,
349	addr->css_icsr, CSS_INBITS);
350	sc->css_if->if_ierrors++;
351	sc->css_flush = 1;
352	}
353
354	if (sc->css_flush) {
355	if (addr->css_icsr & IN_EOM)
356	sc->css_flush = 0;
357	goto setup;
358	}
359
360	len = IMPMTU + (addr->css_iwc << 1);
361	if (len < 0 \|\| len > IMPMTU) {
362	printf("css%d: bad length=%d\n", len);
363	sc->css_if->if_ierrors++;
364	goto setup;
365	}
366
367	/*
368	* The last parameter is always 0 since using
369	* trailers on the ARPAnet is insane.
370	*/
371	m = if_rubaget(&sc->css_ifuba, len, 0);
372	if (m == 0)
373	goto setup;
374	if ((addr->css_icsr & IN_EOM) == 0) {
375	if (sc->css_iq)
376	m_cat(sc->css_iq, m);
377	else
378	sc->css_iq = m;
379	goto setup;
380	}
381	if (sc->css_iq) {
382	m_cat(sc->css_iq, m);
383	m = sc->css_iq;
384	sc->css_iq = 0;
385	}
386	impinput(unit, m);
387
388	setup:
389	/*
390	* Setup for next message.
391	*/
392	info = sc->css_ifuba.ifu_r.ifrw_info;
393	addr->css_iba = (u_short)info;
394	addr->css_iwc = - (IMPMTU >> 1);
395	addr->css_icsr =
396	IN_HRDY \| CSS_IE \| IN_WEN \| ((info & 0x30000) >> 12) \| CSS_GO;
397	}