drivers/s390/net/qeth_tso.c

   1 /*
   2  * linux/drivers/s390/net/qeth_tso.c ($Revision: 1.6 $)
   3  *
   4  * Header file for qeth TCP Segmentation Offload support.
   5  *
   6  * Copyright 2004 IBM Corporation
   7  *
   8  *    Author(s): Frank Pavlic <pavlic@de.ibm.com>
   9  *
  10  *    $Revision: 1.6 $   $Date: 2005/03/24 09:04:18 $
  11  *
  12  */
  13
  14 #include <linux/skbuff.h>
  15 #include <linux/tcp.h>
  16 #include <linux/ip.h>
  17 #include <linux/ipv6.h>
  18 #include <net/ip6_checksum.h>
  19 #include "qeth.h"
  20 #include "qeth_mpc.h"
  21 #include "qeth_tso.h"
  22
  23 /**
  24  * skb already partially prepared
  25  * classic qdio header in skb->data
  26  * */
  27 static inline struct qeth_hdr_tso *
  28 qeth_tso_prepare_skb(struct qeth_card *card, struct sk_buff **skb)
  29 {
  30         int rc = 0;
  31
  32         QETH_DBF_TEXT(trace, 5, "tsoprsk");
  33         rc = qeth_realloc_headroom(card, skb,sizeof(struct qeth_hdr_ext_tso));
  34         if (rc)
  35                 return NULL;
  36
  37         return qeth_push_skb(card, skb, sizeof(struct qeth_hdr_ext_tso));
  38 }
  39
  40 /**
  41  * fill header for a TSO packet
  42  */
  43 static inline void
  44 qeth_tso_fill_header(struct qeth_card *card, struct sk_buff *skb)
  45 {
  46         struct qeth_hdr_tso *hdr;
  47         struct tcphdr *tcph;
  48         struct iphdr *iph;
  49
  50         QETH_DBF_TEXT(trace, 5, "tsofhdr");
  51
  52         hdr  = (struct qeth_hdr_tso *) skb->data;
  53         iph  = skb->nh.iph;
  54         tcph = skb->h.th;
  55         /*fix header to TSO values ...*/
  56         hdr->hdr.hdr.l3.id = QETH_HEADER_TYPE_TSO;
  57         /*set values which are fix for the first approach ...*/
  58         hdr->ext.hdr_tot_len = (__u16) sizeof(struct qeth_hdr_ext_tso);
  59         hdr->ext.imb_hdr_no  = 1;
  60         hdr->ext.hdr_type    = 1;
  61         hdr->ext.hdr_version = 1;
  62         hdr->ext.hdr_len     = 28;
  63         /*insert non-fix values */
  64         hdr->ext.mss = skb_shinfo(skb)->tso_size;
  65         hdr->ext.dg_hdr_len = (__u16)(iph->ihl*4 + tcph->doff*4);
  66         hdr->ext.payload_len = (__u16)(skb->len - hdr->ext.dg_hdr_len -
  67                                        sizeof(struct qeth_hdr_tso));
  68 }
  69
  70 /**
  71  * change some header values as requested by hardware
  72  */
  73 static inline void
  74 qeth_tso_set_tcpip_header(struct qeth_card *card, struct sk_buff *skb)
  75 {
  76         struct iphdr *iph;
  77         struct ipv6hdr *ip6h;
  78         struct tcphdr *tcph;
  79
  80         iph  = skb->nh.iph;
  81         ip6h = skb->nh.ipv6h;
  82         tcph = skb->h.th;
  83
  84         tcph->check = 0;
  85         if (skb->protocol == ETH_P_IPV6) {
  86                 ip6h->payload_len = 0;
  87                 tcph->check = ~csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
  88                                                0, IPPROTO_TCP, 0);
  89                 return;
  90         }
  91         /*OSA want us to set these values ...*/
  92         tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
  93                                          0, IPPROTO_TCP, 0);
  94         iph->tot_len = 0;
  95         iph->check = 0;
  96 }
  97
  98 static inline struct qeth_hdr_tso *
  99 qeth_tso_prepare_packet(struct qeth_card *card, struct sk_buff *skb,
 100                         int ipv, int cast_type)
 101 {
 102         struct qeth_hdr_tso *hdr;
 103         int rc = 0;
 104
 105         QETH_DBF_TEXT(trace, 5, "tsoprep");
 106
 107         /*get headroom for tso qdio header */
 108         hdr = (struct qeth_hdr_tso *) qeth_tso_prepare_skb(card, &skb);
 109         if (hdr == NULL) {
 110                 QETH_DBF_TEXT_(trace, 4, "2err%d", rc);
 111                 return NULL;
 112         }
 113         memset(hdr, 0, sizeof(struct qeth_hdr_tso));
 114         /*fill first 32 bytes of  qdio header as used
 115          *FIXME: TSO has two struct members
 116          * with different names but same size
 117          * */
 118         qeth_fill_header(card, &hdr->hdr, skb, ipv, cast_type);
 119         qeth_tso_fill_header(card, skb);
 120         qeth_tso_set_tcpip_header(card, skb);
 121         return hdr;
 122 }
 123
 124 static inline int
 125 qeth_tso_get_queue_buffer(struct qeth_qdio_out_q *queue)
 126 {
 127         struct qeth_qdio_out_buffer *buffer;
 128         int flush_cnt = 0;
 129
 130         QETH_DBF_TEXT(trace, 5, "tsobuf");
 131
 132         /* force to non-packing*/
 133         if (queue->do_pack)
 134                 queue->do_pack = 0;
 135         buffer = &queue->bufs[queue->next_buf_to_fill];
 136         /* get a new buffer if current is already in use*/
 137         if ((atomic_read(&buffer->state) == QETH_QDIO_BUF_EMPTY) &&
 138             (buffer->next_element_to_fill > 0)) {
 139                 atomic_set(&buffer->state, QETH_QDIO_BUF_PRIMED);
 140                 queue->next_buf_to_fill = (queue->next_buf_to_fill + 1) %
 141                                           QDIO_MAX_BUFFERS_PER_Q;
 142                 flush_cnt++;
 143         }
 144         return flush_cnt;
 145 }
 146
 147 static inline void
 148 __qeth_tso_fill_buffer_frag(struct qeth_qdio_out_buffer *buf,
 149                           struct sk_buff *skb)
 150 {
 151         struct skb_frag_struct *frag;
 152         struct qdio_buffer *buffer;
 153         int fragno, cnt, element;
 154         unsigned long addr;
 155
 156         QETH_DBF_TEXT(trace, 6, "tsfilfrg");
 157
 158         /*initialize variables ...*/
 159         fragno = skb_shinfo(skb)->nr_frags;
 160         buffer = buf->buffer;
 161         element = buf->next_element_to_fill;
 162         /*fill buffer elements .....*/
 163         for (cnt = 0; cnt < fragno; cnt++) {
 164                 frag = &skb_shinfo(skb)->frags[cnt];
 165                 addr = (page_to_pfn(frag->page) << PAGE_SHIFT) +
 166                         frag->page_offset;
 167                 buffer->element[element].addr = (char *)addr;
 168                 buffer->element[element].length = frag->size;
 169                 if (cnt < (fragno - 1))
 170                         buffer->element[element].flags =
 171                                 SBAL_FLAGS_MIDDLE_FRAG;
 172                 else
 173                         buffer->element[element].flags =
 174                                 SBAL_FLAGS_LAST_FRAG;
 175                 element++;
 176         }
 177         buf->next_element_to_fill = element;
 178 }
 179
 180 static inline int
 181 qeth_tso_fill_buffer(struct qeth_qdio_out_buffer *buf,
 182                      struct sk_buff *skb)
 183 {
 184         int length, length_here, element;
 185         int hdr_len;
 186         struct qdio_buffer *buffer;
 187         struct qeth_hdr_tso *hdr;
 188         char *data;
 189
 190         QETH_DBF_TEXT(trace, 3, "tsfilbuf");
 191
 192         /*increment user count and queue skb ...*/
 193         atomic_inc(&skb->users);
 194         skb_queue_tail(&buf->skb_list, skb);
 195
 196         /*initialize all variables...*/
 197         buffer = buf->buffer;
 198         hdr = (struct qeth_hdr_tso *)skb->data;
 199         hdr_len = sizeof(struct qeth_hdr_tso) + hdr->ext.dg_hdr_len;
 200         data = skb->data + hdr_len;
 201         length = skb->len - hdr_len;
 202         element = buf->next_element_to_fill;
 203         /*fill first buffer entry only with header information */
 204         buffer->element[element].addr = skb->data;
 205         buffer->element[element].length = hdr_len;
 206         buffer->element[element].flags = SBAL_FLAGS_FIRST_FRAG;
 207         buf->next_element_to_fill++;
 208
 209         if (skb_shinfo(skb)->nr_frags > 0) {
 210                  __qeth_tso_fill_buffer_frag(buf, skb);
 211                  goto out;
 212         }
 213
 214        /*start filling buffer entries ...*/
 215         element++;
 216         while (length > 0) {
 217                 /* length_here is the remaining amount of data in this page */
 218                 length_here = PAGE_SIZE - ((unsigned long) data % PAGE_SIZE);
 219                 if (length < length_here)
 220                         length_here = length;
 221                 buffer->element[element].addr = data;
 222                 buffer->element[element].length = length_here;
 223                 length -= length_here;
 224                 if (!length)
 225                         buffer->element[element].flags =
 226                                 SBAL_FLAGS_LAST_FRAG;
 227                  else
 228                          buffer->element[element].flags =
 229                                  SBAL_FLAGS_MIDDLE_FRAG;
 230                 data += length_here;
 231                 element++;
 232         }
 233         /*set the buffer to primed  ...*/
 234         buf->next_element_to_fill = element;
 235 out:
 236         atomic_set(&buf->state, QETH_QDIO_BUF_PRIMED);
 237         return 1;
 238 }
 239
 240 int
 241 qeth_tso_send_packet(struct qeth_card *card, struct sk_buff *skb,
 242                      struct qeth_qdio_out_q *queue, int ipv, int cast_type)
 243 {
 244         int flush_cnt = 0;
 245         struct qeth_hdr_tso *hdr;
 246         struct qeth_qdio_out_buffer *buffer;
 247         int start_index;
 248
 249         QETH_DBF_TEXT(trace, 3, "tsosend");
 250
 251         if (!(hdr = qeth_tso_prepare_packet(card, skb, ipv, cast_type)))
 252                 return -ENOMEM;
 253         /*check if skb fits in one SBAL ...*/
 254         if (!(qeth_get_elements_no(card, (void*)hdr, skb)))
 255                 return -EINVAL;
 256         /*lock queue, force switching to non-packing and send it ...*/
 257         while (atomic_compare_and_swap(QETH_OUT_Q_UNLOCKED,
 258                                        QETH_OUT_Q_LOCKED,
 259                                        &queue->state));
 260         start_index = queue->next_buf_to_fill;
 261         buffer = &queue->bufs[queue->next_buf_to_fill];
 262         /*check if card is too busy ...*/
 263         if (atomic_read(&buffer->state) != QETH_QDIO_BUF_EMPTY){
 264                 card->stats.tx_dropped++;
 265                 goto out;
 266         }
 267         /*let's force to non-packing and get a new SBAL*/
 268         flush_cnt += qeth_tso_get_queue_buffer(queue);
 269         buffer = &queue->bufs[queue->next_buf_to_fill];
 270         if (atomic_read(&buffer->state) != QETH_QDIO_BUF_EMPTY) {
 271                 card->stats.tx_dropped++;
 272                 goto out;
 273         }
 274         flush_cnt += qeth_tso_fill_buffer(buffer, skb);
 275         queue->next_buf_to_fill = (queue->next_buf_to_fill + 1) %
 276                                    QDIO_MAX_BUFFERS_PER_Q;
 277 out:
 278         atomic_set(&queue->state, QETH_OUT_Q_UNLOCKED);
 279         if (flush_cnt)
 280                 qeth_flush_buffers(queue, 0, start_index, flush_cnt);
 281         /*do some statistics */
 282         card->stats.tx_packets++;
 283         card->stats.tx_bytes += skb->len;
 284         return 0;
 285 }