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034307a7 SZ |
1 | /** @file\r |
2 | A Dxe Timer Library implementation which uses the Time Stamp Counter in the processor.\r | |
3 | \r | |
4 | For Pentium 4 processors, Intel Xeon processors (family [0FH], models [03H and higher]);\r | |
5 | for Intel Core Solo and Intel Core Duo processors (family [06H], model [0EH]);\r | |
6 | for the Intel Xeon processor 5100 series and Intel Core 2 Duo processors (family [06H], model [0FH]);\r | |
7 | for Intel Core 2 and Intel Xeon processors (family [06H], display_model [17H]);\r | |
8 | for Intel Atom processors (family [06H], display_model [1CH]):\r | |
9 | the time-stamp counter increments at a constant rate.\r | |
10 | That rate may be set by the maximum core-clock to bus-clock ratio of the processor or may be set by\r | |
11 | the maximum resolved frequency at which the processor is booted. The maximum resolved frequency may\r | |
12 | differ from the maximum qualified frequency of the processor.\r | |
13 | \r | |
14 | The specific processor configuration determines the behavior. Constant TSC behavior ensures that the\r | |
15 | duration of each clock tick is uniform and supports the use of the TSC as a wall clock timer even if\r | |
16 | the processor core changes frequency. This is the architectural behavior moving forward.\r | |
17 | \r | |
18 | A Processor's support for invariant TSC is indicated by CPUID.0x80000007.EDX[8].\r | |
19 | \r | |
20 | Copyright (c) 2009 - 2011, Intel Corporation. All rights reserved.<BR>\r | |
21 | This program and the accompanying materials\r | |
22 | are licensed and made available under the terms and conditions of the BSD License\r | |
23 | which accompanies this distribution. The full text of the license may be found at\r | |
24 | http://opensource.org/licenses/bsd-license.php\r | |
25 | \r | |
26 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r | |
27 | WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r | |
28 | \r | |
29 | **/\r | |
30 | \r | |
31 | #include <PiDxe.h>\r | |
32 | #include <Library/UefiBootServicesTableLib.h>\r | |
33 | #include <Library/UefiLib.h>\r | |
34 | #include <Library/DebugLib.h>\r | |
35 | #include <Guid/TscFrequency.h>\r | |
36 | #include "TscTimerLibInternal.h"\r | |
37 | \r | |
38 | UINT64 mTscFrequency;\r | |
39 | \r | |
40 | /** The constructor function determines the actual TSC frequency.\r | |
41 | \r | |
42 | First, Get TSC frequency from system configuration table with TSC frequency GUID,\r | |
43 | if the table is not found, install it.\r | |
44 | This function will always return EFI_SUCCESS.\r | |
45 | \r | |
46 | @param ImageHandle The firmware allocated handle for the EFI image.\r | |
47 | @param SystemTable A pointer to the EFI System Table.\r | |
48 | \r | |
49 | @retval EFI_SUCCESS The constructor always returns EFI_SUCCESS.\r | |
50 | \r | |
51 | **/\r | |
52 | EFI_STATUS\r | |
53 | EFIAPI\r | |
54 | DxeTscTimerLibConstructor (\r | |
55 | IN EFI_HANDLE ImageHandle,\r | |
56 | IN EFI_SYSTEM_TABLE *SystemTable\r | |
57 | )\r | |
58 | {\r | |
59 | EFI_STATUS Status;\r | |
60 | UINT64 *TscFrequency;\r | |
61 | \r | |
d0f65b21 | 62 | TscFrequency = NULL;\r |
034307a7 SZ |
63 | //\r |
64 | // Get TSC frequency from system configuration table with TSC frequency GUID.\r | |
65 | //\r | |
66 | Status = EfiGetSystemConfigurationTable (&gEfiTscFrequencyGuid, (VOID **) &TscFrequency);\r | |
67 | if (Status == EFI_SUCCESS) {\r | |
d0f65b21 | 68 | ASSERT (TscFrequency != NULL);\r |
034307a7 SZ |
69 | mTscFrequency = *TscFrequency;\r |
70 | return EFI_SUCCESS;\r | |
71 | }\r | |
72 | \r | |
73 | //\r | |
74 | // TSC frequency GUID system configuration table is not found, install it.\r | |
75 | //\r | |
76 | \r | |
77 | Status = gBS->AllocatePool (EfiBootServicesData, sizeof (UINT64), (VOID **) &TscFrequency);\r | |
78 | ASSERT_EFI_ERROR (Status);\r | |
79 | \r | |
80 | *TscFrequency = InternalCalculateTscFrequency ();\r | |
81 | //\r | |
82 | // TscFrequency now points to the number of TSC counts per second, install system configuration table for it.\r | |
83 | //\r | |
84 | gBS->InstallConfigurationTable (&gEfiTscFrequencyGuid, TscFrequency);\r | |
85 | \r | |
86 | mTscFrequency = *TscFrequency;\r | |
87 | return EFI_SUCCESS;\r | |
88 | }\r | |
89 | \r | |
90 | /** Get TSC frequency.\r | |
91 | \r | |
92 | @return The number of TSC counts per second.\r | |
93 | \r | |
94 | **/\r | |
95 | UINT64\r | |
96 | InternalGetTscFrequency (\r | |
97 | VOID\r | |
98 | )\r | |
99 | {\r | |
100 | return mTscFrequency;\r | |
101 | }\r | |
102 | \r |