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1 | /** @file\r |
2 | \r | |
3 | Copyright (c) 2004 - 2014, Intel Corporation. All rights reserved.<BR>\r | |
4 | \r\r | |
5 | This program and the accompanying materials are licensed and made available under\r\r | |
6 | the terms and conditions of the BSD License that accompanies this distribution. \r\r | |
7 | The full text of the license may be found at \r\r | |
8 | http://opensource.org/licenses/bsd-license.php. \r\r | |
9 | \r\r | |
10 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, \r\r | |
11 | WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. \r\r | |
12 | \r\r | |
13 | \r | |
14 | \r | |
15 | \r | |
16 | Module Name:\r | |
17 | \r | |
18 | Stall.c\r | |
19 | \r | |
20 | Abstract:\r | |
21 | \r | |
22 | Produce Stall Ppi.\r | |
23 | \r | |
24 | --*/\r | |
25 | \r | |
26 | \r | |
27 | #include "PlatformEarlyInit.h"\r | |
28 | \r | |
29 | \r | |
30 | /**\r | |
31 | \r | |
32 | Waits for at least the given number of microseconds.\r | |
33 | \r | |
34 | @param PeiServices General purpose services available to every PEIM.\r | |
35 | @param This PPI instance structure.\r | |
36 | @param Microseconds Desired length of time to wait.\r | |
37 | \r | |
38 | @retval EFI_SUCCESS If the desired amount of time was passed.\r | |
39 | \r | |
40 | */\r | |
41 | EFI_STATUS\r | |
42 | EFIAPI\r | |
43 | Stall (\r | |
44 | IN CONST EFI_PEI_SERVICES **PeiServices,\r | |
45 | IN CONST EFI_PEI_STALL_PPI *This,\r | |
46 | IN UINTN Microseconds\r | |
47 | )\r | |
48 | {\r | |
49 | UINTN Ticks;\r | |
50 | UINTN Counts;\r | |
51 | UINT32 CurrentTick;\r | |
52 | UINT32 OriginalTick;\r | |
53 | UINT32 RemainingTick;\r | |
54 | \r | |
55 | if (Microseconds == 0) {\r | |
56 | return EFI_SUCCESS;\r | |
57 | }\r | |
58 | \r | |
59 | OriginalTick = IoRead32 (ACPI_BASE_ADDRESS + R_PCH_ACPI_PM1_TMR);\r | |
60 | OriginalTick &= (V_PCH_ACPI_PM1_TMR_MAX_VAL - 1);\r | |
61 | CurrentTick = OriginalTick;\r | |
62 | \r | |
63 | //\r | |
64 | // The timer frequency is 3.579545MHz, so 1 ms corresponds to 3.58 clocks\r | |
65 | //\r | |
66 | Ticks = Microseconds * 358 / 100 + OriginalTick + 1;\r | |
67 | \r | |
68 | //\r | |
69 | // The loops needed for timer overflow\r | |
70 | //\r | |
71 | Counts = (UINTN)RShiftU64((UINT64)Ticks, 24);\r | |
72 | \r | |
73 | //\r | |
74 | // Remaining clocks within one loop\r | |
75 | //\r | |
76 | RemainingTick = Ticks & 0xFFFFFF;\r | |
77 | \r | |
78 | //\r | |
79 | // Do not intend to use TMROF_STS bit of register PM1_STS, because this add extra\r | |
80 | // one I/O operation, and may generate SMI\r | |
81 | //\r | |
82 | while (Counts != 0) {\r | |
83 | CurrentTick = IoRead32 (ACPI_BASE_ADDRESS + R_PCH_ACPI_PM1_TMR) & B_PCH_ACPI_PM1_TMR_VAL;\r | |
84 | if (CurrentTick <= OriginalTick) {\r | |
85 | Counts--;\r | |
86 | }\r | |
87 | OriginalTick = CurrentTick;\r | |
88 | }\r | |
89 | \r | |
90 | while ((RemainingTick > CurrentTick) && (OriginalTick <= CurrentTick)) {\r | |
91 | OriginalTick = CurrentTick;\r | |
92 | CurrentTick = IoRead32 (ACPI_BASE_ADDRESS + R_PCH_ACPI_PM1_TMR) & B_PCH_ACPI_PM1_TMR_VAL;\r | |
93 | }\r | |
94 | \r | |
95 | return EFI_SUCCESS;\r | |
96 | }\r |