gen_gem.h revision b8e80941 
1/*
2 * Copyright © 2018 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 */
23
24#ifndef GEN_GEM_H
25#define GEN_GEM_H
26
27#include <stdint.h>
28
29static inline uint64_t
30gen_canonical_address(uint64_t v)
31{
32   /* From the Broadwell PRM Vol. 2a, MI_LOAD_REGISTER_MEM::MemoryAddress:
33    *
34    *    "This field specifies the address of the memory location where the
35    *    register value specified in the DWord above will read from. The
36    *    address specifies the DWord location of the data. Range =
37    *    GraphicsVirtualAddress[63:2] for a DWord register GraphicsAddress
38    *    [63:48] are ignored by the HW and assumed to be in correct
39    *    canonical form [63:48] == [47]."
40    */
41   const int shift = 63 - 47;
42   return (int64_t)(v << shift) >> shift;
43}
44
45/**
46 * This returns a 48-bit address with the high 16 bits zeroed.
47 *
48 * It's the opposite of gen_canonicalize_address.
49 */
50static inline uint64_t
51gen_48b_address(uint64_t v)
52{
53   const int shift = 63 - 47;
54   return (uint64_t)(v << shift) >> shift;
55}
56
57#endif /* GEN_GEM_H */
58