The code I wrote to write mbufs out using PIO had a bug in the handling
of mb_offset given the right sequence of 1 and 0 byte mbufs. This bug was discovered by John Hood who also provided this fix - which is a rewrite of the routine (and is easier to understand than the code I wrote). Submitted by: John Hood <cgull@smoke.marlboro.vt.us>
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dg
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@ -13,7 +13,7 @@
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* the SMC Elite Ultra (8216), the 3Com 3c503, the NE1000 and NE2000,
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* and a variety of similar clones.
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*
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* $Id: if_ed.c,v 1.48 1994/09/16 13:33:40 davidg Exp $
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* $Id: if_ed.c,v 1.49 1994/10/08 09:24:20 davidg Exp $
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*/
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#include "ed.h"
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@ -2223,9 +2223,8 @@ ed_pio_write_mbufs(sc, m, dst)
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struct mbuf *m;
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unsigned short dst;
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{
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unsigned short len, mb_offset;
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unsigned short len;
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struct mbuf *mp;
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unsigned char residual[2];
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int maxwait = 100; /* about 120us */
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/* First, count up the total number of bytes to copy */
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@ -2249,57 +2248,61 @@ ed_pio_write_mbufs(sc, m, dst)
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/* set remote DMA write */
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outb(sc->nic_addr + ED_P0_CR, ED_CR_RD1 | ED_CR_STA);
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mb_offset = 0;
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/*
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* Transfer the mbuf chain to the NIC memory. The following code isn't
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* too pretty. The problem is that we can only transfer words to the
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* board, and if an mbuf has an odd number of bytes in it, this is a
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* problem. It's not a simple matter of just removing a byte from the
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* next mbuf (adjusting data++ and len--) because this will hose-over
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* the mbuf chain which might be needed later for BPF. Instead, we
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* maintain an offset (mb_offset) which let's us skip over the first
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* byte in the following mbuf.
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*/
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while (m) {
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if (m->m_len - mb_offset) {
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if (sc->isa16bit) {
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if ((m->m_len - mb_offset) > 1)
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outsw(sc->asic_addr + ED_NOVELL_DATA,
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mtod(m, caddr_t) + mb_offset,
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(m->m_len - mb_offset) / 2);
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/*
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* if odd number of bytes, get the odd byte
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* from the next mbuf with data
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*/
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if ((m->m_len - mb_offset) & 1) {
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/* first the last byte in current mbuf */
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residual[0] = *(mtod(m, caddr_t) +
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m->m_len - 1);
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/* advance past any empty mbufs */
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while (m->m_next && (m->m_next->m_len == 0))
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m = m->m_next;
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if (m->m_next) {
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/*
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* remove first byte in next
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* mbuf
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*/
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residual[1] = *(mtod(m->m_next, caddr_t));
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mb_offset = 1;
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}
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outw(sc->asic_addr + ED_NOVELL_DATA,
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*((unsigned short *) residual));
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} else
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mb_offset = 0;
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} else
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outsb(sc->asic_addr + ED_NOVELL_DATA, m->m_data, m->m_len);
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/*
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* Transfer the mbuf chain to the NIC memory.
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* 16-bit cards require that data be transferred as words, and only words.
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* So that case requires some extra code to patch over odd-length mbufs.
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*/
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if (!sc->isa16bit) {
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/* NE1000s are easy */
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while (m) {
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if (m->m_len) {
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outsb(sc->asic_addr + ED_NOVELL_DATA,
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m->m_data, m->m_len);
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}
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m = m->m_next;
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}
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m = m->m_next;
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} else {
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/* NE2000s are a pain */
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unsigned char *data;
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int len, wantbyte;
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unsigned char savebyte[2];
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wantbyte = 0;
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while (m) {
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data = mtod(m, caddr_t);
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len = m->m_len;
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if (len) {
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/* finish the last word */
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if (wantbyte) {
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savebyte[1] = *data;
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outw(sc->asic_addr + ED_NOVELL_DATA,
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*((unsigned short *) savebyte));
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data++;
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len--;
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wantbyte = 0;
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}
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/* output contiguous words */
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if (len > 1) {
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outsw(sc->asic_addr + ED_NOVELL_DATA,
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data, len >> 1);
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data += len & ~1;
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len &= 1;
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}
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/* save last byte, if necessary */
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if (len == 1) {
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savebyte[0] = *data;
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wantbyte = 1;
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}
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}
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m = m->m_next;
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}
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/* spit last byte */
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if (wantbyte)
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outw(sc->asic_addr + ED_NOVELL_DATA,
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*((unsigned short *) savebyte));
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}
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/*
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@ -13,7 +13,7 @@
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* the SMC Elite Ultra (8216), the 3Com 3c503, the NE1000 and NE2000,
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* and a variety of similar clones.
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*
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* $Id: if_ed.c,v 1.48 1994/09/16 13:33:40 davidg Exp $
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* $Id: if_ed.c,v 1.49 1994/10/08 09:24:20 davidg Exp $
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*/
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#include "ed.h"
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@ -2223,9 +2223,8 @@ ed_pio_write_mbufs(sc, m, dst)
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struct mbuf *m;
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unsigned short dst;
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{
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unsigned short len, mb_offset;
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unsigned short len;
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struct mbuf *mp;
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unsigned char residual[2];
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int maxwait = 100; /* about 120us */
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/* First, count up the total number of bytes to copy */
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@ -2249,57 +2248,61 @@ ed_pio_write_mbufs(sc, m, dst)
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/* set remote DMA write */
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outb(sc->nic_addr + ED_P0_CR, ED_CR_RD1 | ED_CR_STA);
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mb_offset = 0;
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/*
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* Transfer the mbuf chain to the NIC memory. The following code isn't
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* too pretty. The problem is that we can only transfer words to the
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* board, and if an mbuf has an odd number of bytes in it, this is a
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* problem. It's not a simple matter of just removing a byte from the
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* next mbuf (adjusting data++ and len--) because this will hose-over
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* the mbuf chain which might be needed later for BPF. Instead, we
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* maintain an offset (mb_offset) which let's us skip over the first
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* byte in the following mbuf.
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*/
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while (m) {
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if (m->m_len - mb_offset) {
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if (sc->isa16bit) {
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if ((m->m_len - mb_offset) > 1)
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outsw(sc->asic_addr + ED_NOVELL_DATA,
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mtod(m, caddr_t) + mb_offset,
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(m->m_len - mb_offset) / 2);
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/*
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* if odd number of bytes, get the odd byte
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* from the next mbuf with data
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*/
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if ((m->m_len - mb_offset) & 1) {
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/* first the last byte in current mbuf */
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residual[0] = *(mtod(m, caddr_t) +
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m->m_len - 1);
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/* advance past any empty mbufs */
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while (m->m_next && (m->m_next->m_len == 0))
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m = m->m_next;
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if (m->m_next) {
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/*
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* remove first byte in next
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* mbuf
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*/
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residual[1] = *(mtod(m->m_next, caddr_t));
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mb_offset = 1;
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}
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outw(sc->asic_addr + ED_NOVELL_DATA,
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*((unsigned short *) residual));
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} else
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mb_offset = 0;
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} else
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outsb(sc->asic_addr + ED_NOVELL_DATA, m->m_data, m->m_len);
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/*
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* Transfer the mbuf chain to the NIC memory.
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* 16-bit cards require that data be transferred as words, and only words.
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* So that case requires some extra code to patch over odd-length mbufs.
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*/
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if (!sc->isa16bit) {
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/* NE1000s are easy */
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while (m) {
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if (m->m_len) {
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outsb(sc->asic_addr + ED_NOVELL_DATA,
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m->m_data, m->m_len);
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}
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m = m->m_next;
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}
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m = m->m_next;
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} else {
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/* NE2000s are a pain */
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unsigned char *data;
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int len, wantbyte;
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unsigned char savebyte[2];
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wantbyte = 0;
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while (m) {
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data = mtod(m, caddr_t);
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len = m->m_len;
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if (len) {
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/* finish the last word */
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if (wantbyte) {
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savebyte[1] = *data;
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outw(sc->asic_addr + ED_NOVELL_DATA,
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*((unsigned short *) savebyte));
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data++;
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len--;
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wantbyte = 0;
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}
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/* output contiguous words */
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if (len > 1) {
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outsw(sc->asic_addr + ED_NOVELL_DATA,
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data, len >> 1);
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data += len & ~1;
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len &= 1;
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}
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/* save last byte, if necessary */
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if (len == 1) {
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savebyte[0] = *data;
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wantbyte = 1;
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}
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}
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m = m->m_next;
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}
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/* spit last byte */
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if (wantbyte)
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outw(sc->asic_addr + ED_NOVELL_DATA,
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*((unsigned short *) savebyte));
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}
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/*
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