projects / mirror_edk2.git / blame
| Commit | Line | Data |
|---|---|---|
| 504214c4 LG |
1 | /** @file \r |
| 2 | \r | |
| 3 | UEFI Miscellaneous boot Services Stall service implementation\r | |
| 28a00297 | 4 | \r |
| 504214c4 | 5 | Copyright (c) 2006 - 2008, Intel Corporation\r |
| 28a00297 | 6 | All rights reserved. This program and the accompanying materials\r |
| 7 | are licensed and made available under the terms and conditions of the BSD License\r | |
| 8 | which accompanies this distribution. The full text of the license may be found at\r | |
| 9 | http://opensource.org/licenses/bsd-license.php\r | |
| 10 | \r | |
| 11 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r | |
| 12 | WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r | |
| 13 | \r | |
| 504214c4 | 14 | **/\r |
| 28a00297 | 15 | \r |
| 16 | //\r | |
| 17 | // Include statements\r | |
| 18 | //\r | |
| 19 | \r | |
| 20 | #include <DxeMain.h>\r | |
| 21 | \r | |
| 22 | \r | |
| 28a00297 | 23 | \r |
| 162ed594 | 24 | /**\r |
| 28a00297 | 25 | Introduces a fine-grained stall.\r |
| 26 | \r | |
| 162ed594 | 27 | @param Microseconds The number of microseconds to stall execution.\r |
| 28a00297 | 28 | \r |
| 162ed594 | 29 | @retval EFI_SUCCESS Execution was stalled for at least the requested \r |
| 30 | amount of microseconds. \r | |
| 31 | @retval EFI_NOT_AVAILABLE_YET gMetronome is not available yet\r | |
| 28a00297 | 32 | \r |
| 162ed594 | 33 | **/\r |
| 34 | EFI_STATUS\r | |
| 35 | EFIAPI\r | |
| 36 | CoreStall (\r | |
| 37 | IN UINTN Microseconds\r | |
| 38 | )\r | |
| 28a00297 | 39 | {\r |
| 40 | UINT32 Counter;\r | |
| 41 | UINT32 Remainder;\r | |
| 42 | \r | |
| 43 | if (gMetronome == NULL) {\r | |
| 44 | return EFI_NOT_AVAILABLE_YET;\r | |
| 45 | }\r | |
| 46 | \r | |
| 47 | //\r | |
| 48 | // Calculate the number of ticks by dividing the number of microseconds by\r | |
| 49 | // the TickPeriod.\r | |
| 50 | // Calcullation is based on 100ns unit.\r | |
| 51 | //\r | |
| 52 | Counter = (UINT32) DivU64x32Remainder (\r | |
| 53 | Microseconds * 10,\r | |
| 54 | gMetronome->TickPeriod,\r | |
| 55 | &Remainder\r | |
| 56 | );\r | |
| 57 | \r | |
| 58 | //\r | |
| 59 | // Call WaitForTick for Counter + 1 ticks to try to guarantee Counter tick\r | |
| 60 | // periods, thus attempting to ensure Microseconds of stall time.\r | |
| 61 | //\r | |
| 62 | if (Remainder != 0) {\r | |
| 63 | Counter++;\r | |
| 64 | }\r | |
| 65 | \r | |
| 66 | gMetronome->WaitForTick (gMetronome, Counter);\r | |
| 67 | \r | |
| 68 | return EFI_SUCCESS;\r | |
| 69 | }\r |