target/linux/ubicom32/files/arch/ubicom32/include/asm/ubicom32ring.h

   1 /*
   2  * arch/ubicom32/include/asm/ubicom32ring.h
   3  * Userspace I/O platform driver for Ubicom32 ring buffers
   4  *
   5  * (C) Copyright 2009, Ubicom, Inc.
   6  *
   7  * This file is part of the Ubicom32 Linux Kernel Port.
   8  *
   9  * The Ubicom32 Linux Kernel Port is free software: you can redistribute
  10  * it and/or modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation, either version 2 of the
  12  * License, or (at your option) any later version.
  13  *
  14  * The Ubicom32 Linux Kernel Port is distributed in the hope that it
  15  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  16  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  17  * the GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with the Ubicom32 Linux Kernel Port.  If not,
  21  * see <http://www.gnu.org/licenses/>.
  22  */
  23
  24 #ifndef _ASM_UBICOM32_UBICOM32RING_H
  25 #define _ASM_UBICOM32_UBICOM32RING_H
  26
  27 #define UIO_UBICOM32RING_REG_VERSION    2
  28
  29 struct uio_ubicom32ring_desc {
  30         volatile unsigned int           head;
  31         volatile unsigned int           tail;
  32         unsigned int                    entries;
  33         volatile unsigned int           ring[0];
  34 };
  35
  36 struct uio_ubicom32ring_regs {
  37         unsigned int                    version;
  38
  39         /*
  40          * Magic type used to identify the ring set.  Each driver will
  41          * have a different magic value.
  42          */
  43         unsigned int                    magic;
  44
  45         /*
  46          * Registers defined by the driver
  47          */
  48         unsigned int                    regs_size;
  49         void                            *regs;
  50
  51         /*
  52          * The locations of the rings
  53          *
  54          * DO NOT ADD ANYTHING BELOW THIS LINE
  55          */
  56         unsigned int                    num_rings;
  57         struct uio_ubicom32ring_desc    *rings[0];
  58 };
  59
  60 /*
  61  * ringtio_ring_flush
  62  */
  63 static inline void ringtio_ring_flush(struct uio_ubicom32ring_desc *rd)
  64 {
  65         rd->head = rd->tail = 0;
  66 }
  67
  68 /*
  69  * ringtio_ring_get
  70  */
  71 static inline int ringtio_ring_get(struct uio_ubicom32ring_desc *rd, void **val)
  72 {
  73         if (rd->head == rd->tail) {
  74                 return 0;
  75         }
  76
  77         *val = (void *)rd->ring[rd->head++];
  78         if (rd->head == rd->entries) {
  79                 rd->head = 0;
  80         }
  81         return 1;
  82 }
  83
  84 /*
  85  * ringtio_ring_put
  86  */
  87 static inline int ringtio_ring_put(struct uio_ubicom32ring_desc *rd, void *val)
  88 {
  89         unsigned int newtail = rd->tail + 1;
  90         if (newtail == rd->entries) {
  91                 newtail = 0;
  92         }
  93
  94         if (newtail == rd->head) {
  95                 return 0;
  96         }
  97
  98         rd->ring[rd->tail] = (unsigned int)val;
  99         rd->tail = newtail;
 100         return 1;
 101 }
 102
 103 #endif /* _ASM_UBICOM32_UBICOM32RING_H */