kernel/drivers/staging/unisys/uislib/uisqueue.c

   1 /* uisqueue.c
   2  *
   3  * Copyright (C) 2010 - 2013 UNISYS CORPORATION
   4  * All rights reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or (at
   9  * your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  14  * NON INFRINGEMENT.  See the GNU General Public License for more
  15  * details.
  16  */
  17
  18 /* @ALL_INSPECTED */
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21
  22 #include "uisutils.h"
  23
  24 /* this is shorter than using __FILE__ (full path name) in
  25  * debug/info/error messages */
  26 #define CURRENT_FILE_PC UISLIB_PC_uisqueue_c
  27 #define __MYFILE__ "uisqueue.c"
  28
  29 #define CHECK_CACHE_ALIGN 0
  30
  31 /*****************************************************/
  32 /* Exported functions                                */
  33 /*****************************************************/
  34
  35 /*
  36  * Routine Description:
  37  * Tries to insert the prebuilt signal pointed to by pSignal into the nth
  38  * Queue of the Channel pointed to by pChannel
  39  *
  40  * Parameters:
  41  * pChannel: (IN) points to the IO Channel
  42  * Queue: (IN) nth Queue of the IO Channel
  43  * pSignal: (IN) pointer to the signal
  44  *
  45  * Assumptions:
  46  * - pChannel, Queue and pSignal are valid.
  47  * - If insertion fails due to a full queue, the caller will determine the
  48  * retry policy (e.g. wait & try again, report an error, etc.).
  49  *
  50  * Return value:
  51  * 1 if the insertion succeeds, 0 if the queue was full.
  52  */
  53 unsigned char spar_signal_insert(struct channel_header __iomem *ch, u32 queue,
  54                                  void *sig)
  55 {
  56         void __iomem *psignal;
  57         unsigned int head, tail, nof;
  58
  59         struct signal_queue_header __iomem *pqhdr =
  60             (struct signal_queue_header __iomem *)
  61                 ((char __iomem *)ch + readq(&ch->ch_space_offset))
  62                 + queue;
  63
  64         /* capture current head and tail */
  65         head = readl(&pqhdr->head);
  66         tail = readl(&pqhdr->tail);
  67
  68         /* queue is full if (head + 1) % n equals tail */
  69         if (((head + 1) % readl(&pqhdr->max_slots)) == tail) {
  70                 nof = readq(&pqhdr->num_overflows) + 1;
  71                 writeq(nof, &pqhdr->num_overflows);
  72                 return 0;
  73         }
  74
  75         /* increment the head index */
  76         head = (head + 1) % readl(&pqhdr->max_slots);
  77
  78         /* copy signal to the head location from the area pointed to
  79          * by pSignal
  80          */
  81         psignal = (char __iomem *)pqhdr + readq(&pqhdr->sig_base_offset) +
  82                 (head * readl(&pqhdr->signal_size));
  83         memcpy_toio(psignal, sig, readl(&pqhdr->signal_size));
  84
  85         mb(); /* channel synch */
  86         writel(head, &pqhdr->head);
  87
  88         writeq(readq(&pqhdr->num_sent) + 1, &pqhdr->num_sent);
  89         return 1;
  90 }
  91 EXPORT_SYMBOL_GPL(spar_signal_insert);
  92
  93 /*
  94  * Routine Description:
  95  * Removes one signal from Channel pChannel's nth Queue at the
  96  * time of the call and copies it into the memory pointed to by
  97  * pSignal.
  98  *
  99  * Parameters:
 100  * pChannel: (IN) points to the IO Channel
 101  * Queue: (IN) nth Queue of the IO Channel
 102  * pSignal: (IN) pointer to where the signals are to be copied
 103  *
 104  * Assumptions:
 105  * - pChannel and Queue are valid.
 106  * - pSignal points to a memory area large enough to hold queue's SignalSize
 107  *
 108  * Return value:
 109  * 1 if the removal succeeds, 0 if the queue was empty.
 110  */
 111 unsigned char
 112 spar_signal_remove(struct channel_header __iomem *ch, u32 queue, void *sig)
 113 {
 114         void __iomem *psource;
 115         unsigned int head, tail;
 116         struct signal_queue_header __iomem *pqhdr =
 117             (struct signal_queue_header __iomem *)((char __iomem *)ch +
 118                                     readq(&ch->ch_space_offset)) + queue;
 119
 120         /* capture current head and tail */
 121         head = readl(&pqhdr->head);
 122         tail = readl(&pqhdr->tail);
 123
 124         /* queue is empty if the head index equals the tail index */
 125         if (head == tail) {
 126                 writeq(readq(&pqhdr->num_empty) + 1, &pqhdr->num_empty);
 127                 return 0;
 128         }
 129
 130         /* advance past the 'empty' front slot */
 131         tail = (tail + 1) % readl(&pqhdr->max_slots);
 132
 133         /* copy signal from tail location to the area pointed to by pSignal */
 134         psource = (char __iomem *)pqhdr + readq(&pqhdr->sig_base_offset) +
 135                 (tail * readl(&pqhdr->signal_size));
 136         memcpy_fromio(sig, psource, readl(&pqhdr->signal_size));
 137
 138         mb(); /* channel synch */
 139         writel(tail, &pqhdr->tail);
 140
 141         writeq(readq(&pqhdr->num_received) + 1,
 142                &pqhdr->num_received);
 143         return 1;
 144 }
 145 EXPORT_SYMBOL_GPL(spar_signal_remove);
 146
 147 /*
 148  * Routine Description:
 149  * Removes all signals present in Channel pChannel's nth Queue at the
 150  * time of the call and copies them into the memory pointed to by
 151  * pSignal.  Returns the # of signals copied as the value of the routine.
 152  *
 153  * Parameters:
 154  * pChannel: (IN) points to the IO Channel
 155  * Queue: (IN) nth Queue of the IO Channel
 156  * pSignal: (IN) pointer to where the signals are to be copied
 157  *
 158  * Assumptions:
 159  * - pChannel and Queue are valid.
 160  * - pSignal points to a memory area large enough to hold Queue's MaxSignals
 161  * # of signals, each of which is Queue's SignalSize.
 162  *
 163  * Return value:
 164  * # of signals copied.
 165  */
 166 unsigned int spar_signal_remove_all(struct channel_header *ch, u32 queue,
 167                                     void *sig)
 168 {
 169         void *psource;
 170         unsigned int head, tail, count = 0;
 171         struct signal_queue_header *pqhdr =
 172             (struct signal_queue_header *)((char *)ch +
 173                                     ch->ch_space_offset) + queue;
 174
 175         /* capture current head and tail */
 176         head = pqhdr->head;
 177         tail = pqhdr->tail;
 178
 179         /* queue is empty if the head index equals the tail index */
 180         if (head == tail)
 181                 return 0;
 182
 183         while (head != tail) {
 184                 /* advance past the 'empty' front slot */
 185                 tail = (tail + 1) % pqhdr->max_slots;
 186
 187                 /* copy signal from tail location to the area pointed
 188                  * to by pSignal
 189                  */
 190                 psource =
 191                     (char *)pqhdr + pqhdr->sig_base_offset +
 192                     (tail * pqhdr->signal_size);
 193                 memcpy((char *)sig + (pqhdr->signal_size * count),
 194                        psource, pqhdr->signal_size);
 195
 196                 mb(); /* channel synch */
 197                 pqhdr->tail = tail;
 198
 199                 count++;
 200                 pqhdr->num_received++;
 201         }
 202
 203         return count;
 204 }
 205
 206 /*
 207  * Routine Description:
 208  * Determine whether a signal queue is empty.
 209  *
 210  * Parameters:
 211  * pChannel: (IN) points to the IO Channel
 212  * Queue: (IN) nth Queue of the IO Channel
 213  *
 214  * Return value:
 215  * 1 if the signal queue is empty, 0 otherwise.
 216  */
 217 unsigned char spar_signalqueue_empty(struct channel_header __iomem *ch,
 218                                      u32 queue)
 219 {
 220         struct signal_queue_header __iomem *pqhdr =
 221             (struct signal_queue_header __iomem *)((char __iomem *)ch +
 222                                     readq(&ch->ch_space_offset)) + queue;
 223         return readl(&pqhdr->head) == readl(&pqhdr->tail);
 224 }
 225 EXPORT_SYMBOL_GPL(spar_signalqueue_empty);
 226
 227 unsigned long long
 228 uisqueue_interlocked_or(unsigned long long __iomem *tgt,
 229                         unsigned long long set)
 230 {
 231         unsigned long long i;
 232         unsigned long long j;
 233
 234         j = readq(tgt);
 235         do {
 236                 i = j;
 237                 j = cmpxchg((__force unsigned long long *)tgt, i, i | set);
 238
 239         } while (i != j);
 240
 241         return j;
 242 }
 243 EXPORT_SYMBOL_GPL(uisqueue_interlocked_or);
 244
 245 unsigned long long
 246 uisqueue_interlocked_and(unsigned long long __iomem *tgt,
 247                          unsigned long long set)
 248 {
 249         unsigned long long i;
 250         unsigned long long j;
 251
 252         j = readq(tgt);
 253         do {
 254                 i = j;
 255                 j = cmpxchg((__force unsigned long long *)tgt, i, i & set);
 256
 257         } while (i != j);
 258
 259         return j;
 260 }
 261 EXPORT_SYMBOL_GPL(uisqueue_interlocked_and);
 262
 263 static u8
 264 do_locked_client_insert(struct uisqueue_info *queueinfo,
 265                         unsigned int whichqueue,
 266                         void *signal,
 267                         spinlock_t *lock,
 268                         u8 *channel_id)
 269 {
 270         unsigned long flags;
 271         u8 rc = 0;
 272
 273         spin_lock_irqsave(lock, flags);
 274         if (!spar_channel_client_acquire_os(queueinfo->chan, channel_id))
 275                 goto unlock;
 276         if (spar_signal_insert(queueinfo->chan, whichqueue, signal)) {
 277                 queueinfo->packets_sent++;
 278                 rc = 1;
 279         }
 280         spar_channel_client_release_os(queueinfo->chan, channel_id);
 281 unlock:
 282         spin_unlock_irqrestore((spinlock_t *)lock, flags);
 283         return rc;
 284 }
 285
 286 int
 287 uisqueue_put_cmdrsp_with_lock_client(struct uisqueue_info *queueinfo,
 288                                      struct uiscmdrsp *cmdrsp,
 289                                      unsigned int whichqueue,
 290                                      void *insertlock,
 291                                      unsigned char issue_irq_if_empty,
 292                                      u64 irq_handle,
 293                                      char oktowait, u8 *channel_id)
 294 {
 295         while (!do_locked_client_insert(queueinfo, whichqueue, cmdrsp,
 296                                         (spinlock_t *)insertlock,
 297                                         channel_id)) {
 298                 if (oktowait != OK_TO_WAIT)
 299                         return 0;       /* failed to queue */
 300
 301                 /* try again */
 302                 set_current_state(TASK_INTERRUPTIBLE);
 303                 schedule_timeout(msecs_to_jiffies(10));
 304         }
 305         return 1;
 306 }
 307 EXPORT_SYMBOL_GPL(uisqueue_put_cmdrsp_with_lock_client);
 308
 309 /* uisqueue_get_cmdrsp gets the cmdrsp entry at the head of the queue
 310  * returns NULL if queue is empty */
 311 int
 312 uisqueue_get_cmdrsp(struct uisqueue_info *queueinfo,
 313                     void *cmdrsp, unsigned int whichqueue)
 314 {
 315         if (!spar_signal_remove(queueinfo->chan, whichqueue, cmdrsp))
 316                 return 0;
 317
 318         queueinfo->packets_received++;
 319
 320         return 1;               /* Success */
 321 }
 322 EXPORT_SYMBOL_GPL(uisqueue_get_cmdrsp);