]>
Commit | Line | Data |
---|---|---|
2ef2b01e A |
1 | /** @file\r |
2 | \r | |
60274cca | 3 | Copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>\r |
c9bf2a9e | 4 | Copyright (c) 2013, ARM Ltd. All rights reserved.\r |
5 | \r | |
878b807a | 6 | SPDX-License-Identifier: BSD-2-Clause-Patent\r |
2ef2b01e A |
7 | \r |
8 | **/\r | |
9 | \r | |
10 | #include <PiDxe.h>\r | |
11 | \r | |
12 | #include <Library/BaseLib.h>\r | |
13 | #include <Library/DebugLib.h>\r | |
14 | #include <Library/BaseMemoryLib.h>\r | |
15 | #include <Library/UefiBootServicesTableLib.h>\r | |
16 | #include <Library/UefiLib.h>\r | |
17 | #include <Library/PcdLib.h>\r | |
18 | #include <Library/TimerLib.h>\r | |
19 | \r | |
20 | #include <Protocol/Metronome.h>\r | |
21 | \r | |
2ef2b01e A |
22 | EFI_STATUS\r |
23 | EFIAPI\r | |
24 | WaitForTick (\r | |
25 | IN EFI_METRONOME_ARCH_PROTOCOL *This,\r | |
26 | IN UINT32 TickNumber\r | |
c9bf2a9e | 27 | );\r |
2ef2b01e A |
28 | \r |
29 | /**\r | |
7ca9e5a4 | 30 | Interface structure for the Metronome Architectural Protocol.\r |
2ef2b01e A |
31 | \r |
32 | @par Protocol Description:\r | |
33 | This protocol provides access to a known time source in the platform to the\r | |
c9bf2a9e | 34 | core. The core uses this known time source to produce core services that\r |
35 | require calibrated delays.\r | |
2ef2b01e A |
36 | \r |
37 | @param WaitForTick\r | |
c9bf2a9e | 38 | Waits for a specified number of ticks from a known time source\r |
39 | in the platform. The actual time passed between entry of this\r | |
40 | function and the first tick is between 0 and TickPeriod 100 nS\r | |
41 | units. If you want to guarantee that at least TickPeriod time\r | |
2ef2b01e A |
42 | has elapsed, wait for two ticks.\r |
43 | \r | |
44 | @param TickPeriod\r | |
c9bf2a9e | 45 | The period of platform's known time source in 100 nS units.\r |
46 | This value on any platform must be at least 10 uS, and must not\r | |
47 | exceed 200 uS. The value in this field is a constant that must\r | |
48 | not be modified after the Metronome architectural protocol is\r | |
2ef2b01e A |
49 | installed. All consumers must treat this as a read-only field.\r |
50 | \r | |
51 | **/\r | |
52 | EFI_METRONOME_ARCH_PROTOCOL gMetronome = {\r | |
53 | WaitForTick,\r | |
990976ab | 54 | FixedPcdGet32 (PcdMetronomeTickPeriod)\r |
2ef2b01e A |
55 | };\r |
56 | \r | |
57 | \r | |
c9bf2a9e | 58 | /**\r |
59 | The WaitForTick() function waits for the number of ticks specified by\r | |
60 | TickNumber from a known time source in the platform. If TickNumber of\r | |
61 | ticks are detected, then EFI_SUCCESS is returned. The actual time passed\r | |
62 | between entry of this function and the first tick is between 0 and\r | |
63 | TickPeriod 100 nS units. If you want to guarantee that at least TickPeriod\r | |
64 | time has elapsed, wait for two ticks. This function waits for a hardware\r | |
65 | event to determine when a tick occurs. It is possible for interrupt\r | |
66 | processing, or exception processing to interrupt the execution of the\r | |
67 | WaitForTick() function. Depending on the hardware source for the ticks, it\r | |
68 | is possible for a tick to be missed. This function cannot guarantee that\r | |
69 | ticks will not be missed. If a timeout occurs waiting for the specified\r | |
70 | number of ticks, then EFI_TIMEOUT is returned.\r | |
71 | \r | |
72 | @param This The EFI_METRONOME_ARCH_PROTOCOL instance.\r | |
73 | @param TickNumber Number of ticks to wait.\r | |
74 | \r | |
75 | @retval EFI_SUCCESS The wait for the number of ticks specified by TickNumber\r | |
76 | succeeded.\r | |
77 | @retval EFI_TIMEOUT A timeout occurred waiting for the specified number of ticks.\r | |
78 | \r | |
79 | **/\r | |
80 | EFI_STATUS\r | |
81 | EFIAPI\r | |
82 | WaitForTick (\r | |
83 | IN EFI_METRONOME_ARCH_PROTOCOL *This,\r | |
84 | IN UINT32 TickNumber\r | |
85 | )\r | |
86 | {\r | |
87 | //\r | |
88 | // Compute how long to stall the CPU.\r | |
89 | // gMetronome.TickPeriod is in 100 ns units so it needs to be divided by 10\r | |
90 | // to get it in microseconds units.\r | |
91 | //\r | |
92 | MicroSecondDelay (TickNumber * gMetronome.TickPeriod / 10);\r | |
93 | return EFI_SUCCESS;\r | |
94 | }\r | |
95 | \r | |
96 | \r | |
2ef2b01e A |
97 | EFI_HANDLE gMetronomeHandle = NULL;\r |
98 | \r | |
99 | \r | |
100 | \r | |
101 | /**\r | |
102 | Initialize the state information for the CPU Architectural Protocol\r | |
103 | \r | |
104 | @param ImageHandle of the loaded driver\r | |
105 | @param SystemTable Pointer to the System Table\r | |
106 | \r | |
107 | @retval EFI_SUCCESS Protocol registered\r | |
108 | @retval EFI_OUT_OF_RESOURCES Cannot allocate protocol data structure\r | |
109 | @retval EFI_DEVICE_ERROR Hardware problems\r | |
110 | \r | |
111 | **/\r | |
112 | EFI_STATUS\r | |
7609c047 | 113 | EFIAPI\r |
2ef2b01e A |
114 | MetronomeInitialize (\r |
115 | IN EFI_HANDLE ImageHandle,\r | |
116 | IN EFI_SYSTEM_TABLE *SystemTable\r | |
117 | )\r | |
118 | {\r | |
119 | EFI_STATUS Status;\r | |
c9bf2a9e | 120 | \r |
2ef2b01e A |
121 | //\r |
122 | // Do any hardware init required to make WaitForTick () to work here.\r | |
123 | //\r | |
124 | \r | |
125 | Status = gBS->InstallMultipleProtocolInterfaces (\r | |
126 | &gMetronomeHandle,\r | |
127 | &gEfiMetronomeArchProtocolGuid, &gMetronome,\r | |
128 | NULL\r | |
129 | );\r | |
130 | ASSERT_EFI_ERROR (Status);\r | |
131 | \r | |
132 | return Status;\r | |
133 | }\r | |
134 | \r |