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Diffstat (limited to 'common/ipc_ring.h')
| -rw-r--r-- | common/ipc_ring.h | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/common/ipc_ring.h b/common/ipc_ring.h new file mode 100644 index 00000000..1d9b3e1e --- /dev/null +++ b/common/ipc_ring.h @@ -0,0 +1,135 @@ +/* + Copyright (C) 2009 Red Hat, Inc. + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions are + met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in + the documentation and/or other materials provided with the + distribution. + * Neither the name of the copyright holder nor the names of its + contributors may be used to endorse or promote products derived + from this software without specific prior written permission. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS + IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A + PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +*/ + + +#ifndef _H_RING_ +#define _H_RING_ + + +#define MSB_MASK4(x) \ + (((x) & 0x8) ? 0x8 : \ + ((x) & 0x4) ? 0x4 : \ + ((x) & 0x2) ? 0x2 : \ + ((x) & 0x1) ? 0x1 : 0) + +#define MSB_MASK8(x) \ + (((x) & 0xf0) ? MSB_MASK4((x) >> 4) << 4 : MSB_MASK4(x)) + +#define MSB_MASK16(x) \ + (((x) & 0xff00) ? MSB_MASK8((x) >> 8) << 8 : MSB_MASK8(x)) + +#define MSB_MASK(x) \ + (((x) & 0xffff0000) ? MSB_MASK16((x) >> 16) << 16 : MSB_MASK16(x)) + +#define POWER2_ALIGN(x) MSB_MASK((x) * 2 - 1) + + +#define _TOSHIFT_4(x) \ + (((x) & 0x8) ? 3 : \ + ((x) & 0x4) ? 2 : \ + ((x) & 0x2) ? 1 : 0) + +#define _TOSHIFT_8(x) \ + (((x) & 0xf0) ? _TOSHIFT_4((x) >> 4) + 4 : _TOSHIFT_4(x)) + +#define _TOSHIFT_16(x) \ + (((x) & 0xff00) ? _TOSHIFT_8((x) >> 8) + 8 : _TOSHIFT_8(x)) + +#define PAWER2_TO_SHIFT(x) \ + (((x) & 0xffff0000) ? _TOSHIFT_16((x) >> 16) + 16 : _TOSHIFT_16(x)) + + + +#define RING_DECLARE(name, el_type, size) \ +typedef struct ATTR_PACKED name##_ring_el { \ + union { \ + el_type el; \ + UINT8 data[POWER2_ALIGN(sizeof(el_type))]; \ + } ; \ +} name##_ring_el; \ + \ +typedef struct ATTR_PACKED name { \ + UINT32 num_items; \ + UINT32 prod; \ + UINT32 notify_on_prod; \ + UINT32 cons; \ + UINT32 notify_on_cons; \ + name##_ring_el items[POWER2_ALIGN(size)]; \ +} name; + + +#define RING_INIT(r) \ + (r)->num_items = sizeof((r)->items) >> \ + PAWER2_TO_SHIFT(sizeof((r)->items[0])); \ + (r)->prod = (r)->cons = 0; \ + (r)->notify_on_prod = 1; \ + (r)->notify_on_cons = 0; + + +#define RING_INDEX_MASK(r) ((r)->num_items - 1) + +#define RING_IS_PACKED(r) (sizeof((r)->items[0]) == sizeof((r)->items[0]).el) + +#define RING_IS_EMPTY(r) ((r)->cons == (r)->prod) + +#define RING_IS_FULL(r) (((r)->prod - (r)->cons) == (r)->num_items) + +#define RING_PROD_ITEM(r) (&(r)->items[(r)->prod & RING_INDEX_MASK(r)].el) + +#define RING_PROD_WAIT(r, wait) \ + if (((wait) = RING_IS_FULL(r))) { \ + (r)->notify_on_cons = (r)->cons + 1; \ + mb(); \ + (wait) = RING_IS_FULL(r); \ + } + +#define RING_PUSH(r, notify) \ + (r)->prod++; \ + mb(); \ + (notify) = (r)->prod == (r)->notify_on_prod; + + +#define RING_CONS_ITEM(r) (&(r)->items[(r)->cons & RING_INDEX_MASK(r)].el) + +#define RING_CONS_WAIT(r, wait) \ + if (((wait) = RING_IS_EMPTY(r))) { \ + (r)->notify_on_prod = (r)->prod + 1; \ + mb(); \ + (wait) = RING_IS_EMPTY(r); \ + } + +#define RING_POP(r, notify) \ + (r)->cons++; \ + mb(); \ + (notify) = (r)->cons == (r)->notify_on_cons; + + + +#endif |