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 | |
| 23 | EFI_STATUS\r | |
| 24 | EFIAPI\r | |
| 25 | CoreStall (\r | |
| 26 | IN UINTN Microseconds\r | |
| 27 | )\r | |
| 28 | /*++\r | |
| 29 | \r | |
| 30 | Routine Description:\r | |
| 31 | \r | |
| 32 | Introduces a fine-grained stall.\r | |
| 33 | \r | |
| 34 | Arguments:\r | |
| 35 | \r | |
| 36 | Microseconds The number of microseconds to stall execution\r | |
| 37 | \r | |
| 38 | Returns:\r | |
| 39 | \r | |
| 40 | EFI_SUCCESS - Execution was stalled for at least the requested amount\r | |
| 41 | of microseconds.\r | |
| 42 | \r | |
| 43 | EFI_NOT_AVAILABLE_YET - gMetronome is not available yet\r | |
| 44 | \r | |
| 45 | --*/\r | |
| 46 | {\r | |
| 47 | UINT32 Counter;\r | |
| 48 | UINT32 Remainder;\r | |
| 49 | \r | |
| 50 | if (gMetronome == NULL) {\r | |
| 51 | return EFI_NOT_AVAILABLE_YET;\r | |
| 52 | }\r | |
| 53 | \r | |
| 54 | //\r | |
| 55 | // Calculate the number of ticks by dividing the number of microseconds by\r | |
| 56 | // the TickPeriod.\r | |
| 57 | // Calcullation is based on 100ns unit.\r | |
| 58 | //\r | |
| 59 | Counter = (UINT32) DivU64x32Remainder (\r | |
| 60 | Microseconds * 10,\r | |
| 61 | gMetronome->TickPeriod,\r | |
| 62 | &Remainder\r | |
| 63 | );\r | |
| 64 | \r | |
| 65 | //\r | |
| 66 | // Call WaitForTick for Counter + 1 ticks to try to guarantee Counter tick\r | |
| 67 | // periods, thus attempting to ensure Microseconds of stall time.\r | |
| 68 | //\r | |
| 69 | if (Remainder != 0) {\r | |
| 70 | Counter++;\r | |
| 71 | }\r | |
| 72 | \r | |
| 73 | gMetronome->WaitForTick (gMetronome, Counter);\r | |
| 74 | \r | |
| 75 | return EFI_SUCCESS;\r | |
| 76 | }\r |