source: rtems/c/src/lib/libbsp/powerpc/beatnik/network/if_mve/mve_smallbuf_tst.c @ 6273201

#include <rtems.h>
#include <bsp.h>
#include <bsp/if_mve_pub.h>
#include <stdlib.h>
#include <stdio.h>

/* Demo for the mv64360 ethernet quirk:
 *
 * $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
 * $$ buffer segments < 8 bytes must be aligned $$
 * $$ to 8 bytes but larger segments are not    $$
 * $$ sensitive to alignment.                   $$
 * $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
 *
 * How to use:
 *
 *   Init MVE driver on (unused) unit 2:
 *
 *    mve = mvtst_init(2)
 *
 *    data = { 1,2,3,4,5,6,7,8,9,0xa,0xb, ... }
 *
 *   Alloc 2-element mbuf chain (1st holds an
 *   ethernet header which is > 8bytes so we can't
 *   test this with only 1 mbuf. The 2nd mbuf holds
 *   a small fragment of data).
 *
 *     mb  = mvtst_getbuf(mve)
 *
 *   Copy data into aligned area inside 2nd mbuf,
 *   (so that you can see if the chip starts using
 *   the aligned area rather than the unaligned
 *   buffer pointer). Point mbuf's data pointer
 *   at 'off'set from the aligned area:
 *
 *     mvtst_putbuf(mb, data, len, offset)
 *
 *   Send chain off:
 *
 *    BSP_mve_send_buf(mve, mb, 0, 0)
 *
 *   Watch raw data:
 *
 *    tcpdump -XX -vv -s0 ether host <my-ether-addr>
 *
 *   E.g, if offset = 1, len = 2 then we would like
 *   to see 
 *  
 *   GOOD:
 *           < 14 header bytes > 0x02, 0x03

 *   but if the chip starts DMA at aligned address
 *   we see instead
 *   BAD:
 *           < 14 header bytes > 0x01, 0x02
 */

static inline void *rmalloc(size_t l) { return malloc(l); }
static inline void  rfree(void *p) { return free(p); }

#define _KERNEL
#include <sys/mbuf.h>

static void
cleanup_buf(void *u_b, void *closure, int error)
{
rtems_bsdnet_semaphore_obtain();
        m_freem((struct mbuf*)u_b);
rtems_bsdnet_semaphore_release();
}

struct mbuf *mvtst_getbuf(struct mveth_private *mp)
{
struct mbuf *m,*n;

        if ( !mp ) {
                printf("need driver ptr arg\n");
                return 0;
        }
rtems_bsdnet_semaphore_obtain();
        MGETHDR(m, M_DONTWAIT, MT_DATA);
        MGET(n, M_DONTWAIT, MT_DATA);
        m->m_next = n;
rtems_bsdnet_semaphore_release();
        /* Ethernet header */
        memset( mtod(m, unsigned char*), 0xff, 6);
        BSP_mve_read_eaddr(mp, mtod(m, unsigned char*) + 6);
        /* Arbitrary; setting to IP but we don't bother
         * to setup a real IP header. We just watch the
         * raw packet contents...
         */
        mtod(m, unsigned char*)[12] = 0x08;
        mtod(m, unsigned char*)[13] = 0x00;
        m->m_pkthdr.len = m->m_len = 14;
        n->m_len = 0;
        return m;
}

int
mvtst_putbuf(struct mbuf *m, void *data, int len, int off)
{
int i;
        if ( m ) {
                m->m_pkthdr.len += len;
        if ( ( m= m->m_next ) ) {
                m->m_len = len;
                memcpy(mtod(m, void*), data, 32);
                m->m_data += off;
                printf("m.dat: 0x%08x, m.data: 0x%08x\n", m->m_dat, m->m_data);
                for ( i=0; i< 16; i++ ) {
                        printf(" %02x,",mtod(m, unsigned char*)[i]);
                }
                printf("\n");
        }
        }
        
        return 0;
}

static void *alloc_rxbuf(int *p_size, unsigned long *paddr)
{
        return *(void**)paddr = rmalloc((*p_size = 1800));
}

static void consume_buf(void *buf, void *closure, int len)
{
        rfree(buf);
}

void *
mvtst_init(int unit)
{
struct mveth_private *mp;
        mp = BSP_mve_setup(
                unit, 0,
                cleanup_buf, 0,
                alloc_rxbuf,
                consume_buf, 0,
                10, 10,
                0);
        if ( mp )
                BSP_mve_init_hw(mp, 0, 0);
        return mp;
}