drivers/net/can/rx-offload.c

   1 /*
   2  * Copyright (c) 2014 David Jander, Protonic Holland
   3  * Copyright (C) 2014-2017 Pengutronix, Marc Kleine-Budde <kernel@pengutronix.de>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the version 2 of the GNU General Public License
   7  * as published by the Free Software Foundation
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <linux/can/dev.h>
  19 #include <linux/can/rx-offload.h>
  20
  21 struct can_rx_offload_cb {
  22         u32 timestamp;
  23 };
  24
  25 static inline struct can_rx_offload_cb *can_rx_offload_get_cb(struct sk_buff *skb)
  26 {
  27         BUILD_BUG_ON(sizeof(struct can_rx_offload_cb) > sizeof(skb->cb));
  28
  29         return (struct can_rx_offload_cb *)skb->cb;
  30 }
  31
  32 static inline bool can_rx_offload_le(struct can_rx_offload *offload, unsigned int a, unsigned int b)
  33 {
  34         if (offload->inc)
  35                 return a <= b;
  36         else
  37                 return a >= b;
  38 }
  39
  40 static inline unsigned int can_rx_offload_inc(struct can_rx_offload *offload, unsigned int *val)
  41 {
  42         if (offload->inc)
  43                 return (*val)++;
  44         else
  45                 return (*val)--;
  46 }
  47
  48 static int can_rx_offload_napi_poll(struct napi_struct *napi, int quota)
  49 {
  50         struct can_rx_offload *offload = container_of(napi, struct can_rx_offload, napi);
  51         struct net_device *dev = offload->dev;
  52         struct net_device_stats *stats = &dev->stats;
  53         struct sk_buff *skb;
  54         int work_done = 0;
  55
  56         while ((work_done < quota) &&
  57                (skb = skb_dequeue(&offload->skb_queue))) {
  58                 struct can_frame *cf = (struct can_frame *)skb->data;
  59
  60                 work_done++;
  61                 stats->rx_packets++;
  62                 stats->rx_bytes += cf->can_dlc;
  63                 netif_receive_skb(skb);
  64         }
  65
  66         if (work_done < quota) {
  67                 napi_complete_done(napi, work_done);
  68
  69                 /* Check if there was another interrupt */
  70                 if (!skb_queue_empty(&offload->skb_queue))
  71                         napi_reschedule(&offload->napi);
  72         }
  73
  74         can_led_event(offload->dev, CAN_LED_EVENT_RX);
  75
  76         return work_done;
  77 }
  78
  79 static inline void __skb_queue_add_sort(struct sk_buff_head *head, struct sk_buff *new,
  80                                         int (*compare)(struct sk_buff *a, struct sk_buff *b))
  81 {
  82         struct sk_buff *pos, *insert = NULL;
  83
  84         skb_queue_reverse_walk(head, pos) {
  85                 const struct can_rx_offload_cb *cb_pos, *cb_new;
  86
  87                 cb_pos = can_rx_offload_get_cb(pos);
  88                 cb_new = can_rx_offload_get_cb(new);
  89
  90                 netdev_dbg(new->dev,
  91                            "%s: pos=0x%08x, new=0x%08x, diff=%10d, queue_len=%d\n",
  92                            __func__,
  93                            cb_pos->timestamp, cb_new->timestamp,
  94                            cb_new->timestamp - cb_pos->timestamp,
  95                            skb_queue_len(head));
  96
  97                 if (compare(pos, new) < 0)
  98                         continue;
  99                 insert = pos;
 100                 break;
 101         }
 102         if (!insert)
 103                 __skb_queue_head(head, new);
 104         else
 105                 __skb_queue_after(head, insert, new);
 106 }
 107
 108 static int can_rx_offload_compare(struct sk_buff *a, struct sk_buff *b)
 109 {
 110         const struct can_rx_offload_cb *cb_a, *cb_b;
 111
 112         cb_a = can_rx_offload_get_cb(a);
 113         cb_b = can_rx_offload_get_cb(b);
 114
 115         /* Substract two u32 and return result as int, to keep
 116          * difference steady around the u32 overflow.
 117          */
 118         return cb_b->timestamp - cb_a->timestamp;
 119 }
 120
 121 static struct sk_buff *can_rx_offload_offload_one(struct can_rx_offload *offload, unsigned int n)
 122 {
 123         struct sk_buff *skb = NULL;
 124         struct can_rx_offload_cb *cb;
 125         struct can_frame *cf;
 126         int ret;
 127
 128         /* If queue is full or skb not available, read to discard mailbox */
 129         if (likely(skb_queue_len(&offload->skb_queue) <=
 130                    offload->skb_queue_len_max))
 131                 skb = alloc_can_skb(offload->dev, &cf);
 132
 133         if (!skb) {
 134                 struct can_frame cf_overflow;
 135                 u32 timestamp;
 136
 137                 ret = offload->mailbox_read(offload, &cf_overflow,
 138                                             &timestamp, n);
 139                 if (ret)
 140                         offload->dev->stats.rx_dropped++;
 141
 142                 return NULL;
 143         }
 144
 145         cb = can_rx_offload_get_cb(skb);
 146         ret = offload->mailbox_read(offload, cf, &cb->timestamp, n);
 147         if (!ret) {
 148                 kfree_skb(skb);
 149                 return NULL;
 150         }
 151
 152         return skb;
 153 }
 154
 155 int can_rx_offload_irq_offload_timestamp(struct can_rx_offload *offload, u64 pending)
 156 {
 157         struct sk_buff_head skb_queue;
 158         unsigned int i;
 159
 160         __skb_queue_head_init(&skb_queue);
 161
 162         for (i = offload->mb_first;
 163              can_rx_offload_le(offload, i, offload->mb_last);
 164              can_rx_offload_inc(offload, &i)) {
 165                 struct sk_buff *skb;
 166
 167                 if (!(pending & BIT_ULL(i)))
 168                         continue;
 169
 170                 skb = can_rx_offload_offload_one(offload, i);
 171                 if (!skb)
 172                         break;
 173
 174                 __skb_queue_add_sort(&skb_queue, skb, can_rx_offload_compare);
 175         }
 176
 177         if (!skb_queue_empty(&skb_queue)) {
 178                 unsigned long flags;
 179                 u32 queue_len;
 180
 181                 spin_lock_irqsave(&offload->skb_queue.lock, flags);
 182                 skb_queue_splice_tail(&skb_queue, &offload->skb_queue);
 183                 spin_unlock_irqrestore(&offload->skb_queue.lock, flags);
 184
 185                 if ((queue_len = skb_queue_len(&offload->skb_queue)) >
 186                     (offload->skb_queue_len_max / 8))
 187                         netdev_dbg(offload->dev, "%s: queue_len=%d\n",
 188                                    __func__, queue_len);
 189
 190                 can_rx_offload_schedule(offload);
 191         }
 192
 193         return skb_queue_len(&skb_queue);
 194 }
 195 EXPORT_SYMBOL_GPL(can_rx_offload_irq_offload_timestamp);
 196
 197 int can_rx_offload_irq_offload_fifo(struct can_rx_offload *offload)
 198 {
 199         struct sk_buff *skb;
 200         int received = 0;
 201
 202         while ((skb = can_rx_offload_offload_one(offload, 0))) {
 203                 skb_queue_tail(&offload->skb_queue, skb);
 204                 received++;
 205         }
 206
 207         if (received)
 208                 can_rx_offload_schedule(offload);
 209
 210         return received;
 211 }
 212 EXPORT_SYMBOL_GPL(can_rx_offload_irq_offload_fifo);
 213
 214 int can_rx_offload_queue_sorted(struct can_rx_offload *offload,
 215                                 struct sk_buff *skb, u32 timestamp)
 216 {
 217         struct can_rx_offload_cb *cb;
 218         unsigned long flags;
 219
 220         if (skb_queue_len(&offload->skb_queue) >
 221             offload->skb_queue_len_max)
 222                 return -ENOMEM;
 223
 224         cb = can_rx_offload_get_cb(skb);
 225         cb->timestamp = timestamp;
 226
 227         spin_lock_irqsave(&offload->skb_queue.lock, flags);
 228         __skb_queue_add_sort(&offload->skb_queue, skb, can_rx_offload_compare);
 229         spin_unlock_irqrestore(&offload->skb_queue.lock, flags);
 230
 231         can_rx_offload_schedule(offload);
 232
 233         return 0;
 234 }
 235 EXPORT_SYMBOL_GPL(can_rx_offload_queue_sorted);
 236
 237 unsigned int can_rx_offload_get_echo_skb(struct can_rx_offload *offload,
 238                                          unsigned int idx, u32 timestamp)
 239 {
 240         struct net_device *dev = offload->dev;
 241         struct net_device_stats *stats = &dev->stats;
 242         struct sk_buff *skb;
 243         u8 len;
 244         int err;
 245
 246         skb = __can_get_echo_skb(dev, idx, &len);
 247         if (!skb)
 248                 return 0;
 249
 250         err = can_rx_offload_queue_sorted(offload, skb, timestamp);
 251         if (err) {
 252                 stats->rx_errors++;
 253                 stats->tx_fifo_errors++;
 254         }
 255
 256         return len;
 257 }
 258 EXPORT_SYMBOL_GPL(can_rx_offload_get_echo_skb);
 259
 260 int can_rx_offload_queue_tail(struct can_rx_offload *offload,
 261                               struct sk_buff *skb)
 262 {
 263         if (skb_queue_len(&offload->skb_queue) >
 264             offload->skb_queue_len_max)
 265                 return -ENOMEM;
 266
 267         skb_queue_tail(&offload->skb_queue, skb);
 268         can_rx_offload_schedule(offload);
 269
 270         return 0;
 271 }
 272 EXPORT_SYMBOL_GPL(can_rx_offload_queue_tail);
 273
 274 static int can_rx_offload_init_queue(struct net_device *dev, struct can_rx_offload *offload, unsigned int weight)
 275 {
 276         offload->dev = dev;
 277
 278         /* Limit queue len to 4x the weight (rounted to next power of two) */
 279         offload->skb_queue_len_max = 2 << fls(weight);
 280         offload->skb_queue_len_max *= 4;
 281         skb_queue_head_init(&offload->skb_queue);
 282
 283         can_rx_offload_reset(offload);
 284         netif_napi_add(dev, &offload->napi, can_rx_offload_napi_poll, weight);
 285
 286         dev_dbg(dev->dev.parent, "%s: skb_queue_len_max=%d\n",
 287                 __func__, offload->skb_queue_len_max);
 288
 289         return 0;
 290 }
 291
 292 int can_rx_offload_add_timestamp(struct net_device *dev, struct can_rx_offload *offload)
 293 {
 294         unsigned int weight;
 295
 296         if (offload->mb_first > BITS_PER_LONG_LONG ||
 297             offload->mb_last > BITS_PER_LONG_LONG || !offload->mailbox_read)
 298                 return -EINVAL;
 299
 300         if (offload->mb_first < offload->mb_last) {
 301                 offload->inc = true;
 302                 weight = offload->mb_last - offload->mb_first;
 303         } else {
 304                 offload->inc = false;
 305                 weight = offload->mb_first - offload->mb_last;
 306         }
 307
 308         return can_rx_offload_init_queue(dev, offload, weight);
 309 }
 310 EXPORT_SYMBOL_GPL(can_rx_offload_add_timestamp);
 311
 312 int can_rx_offload_add_fifo(struct net_device *dev, struct can_rx_offload *offload, unsigned int weight)
 313 {
 314         if (!offload->mailbox_read)
 315                 return -EINVAL;
 316
 317         return can_rx_offload_init_queue(dev, offload, weight);
 318 }
 319 EXPORT_SYMBOL_GPL(can_rx_offload_add_fifo);
 320
 321 void can_rx_offload_enable(struct can_rx_offload *offload)
 322 {
 323         can_rx_offload_reset(offload);
 324         napi_enable(&offload->napi);
 325 }
 326 EXPORT_SYMBOL_GPL(can_rx_offload_enable);
 327
 328 void can_rx_offload_del(struct can_rx_offload *offload)
 329 {
 330         netif_napi_del(&offload->napi);
 331         skb_queue_purge(&offload->skb_queue);
 332 }
 333 EXPORT_SYMBOL_GPL(can_rx_offload_del);
 334
 335 void can_rx_offload_reset(struct can_rx_offload *offload)
 336 {
 337 }
 338 EXPORT_SYMBOL_GPL(can_rx_offload_reset);