| Vishal Bhoj | 82c8071 | 2015-12-15 21:13:33 +0530 | [diff] [blame] | 1 | /** @file
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| 2 |
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| 3 | Stateless fw_cfg library implementation.
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| 4 |
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| 5 | Clients must call QemuFwCfgIsAvailable() first.
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| 6 |
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| 7 | Copyright (C) 2013, Red Hat, Inc.
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| 8 | Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>
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| 9 |
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| 10 | This program and the accompanying materials are licensed and made available
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| 11 | under the terms and conditions of the BSD License which accompanies this
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| 12 | distribution. The full text of the license may be found at
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| 13 | http://opensource.org/licenses/bsd-license.php
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| 14 |
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| 15 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
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| 16 | WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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| 17 | **/
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| 18 |
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| 19 | #include <Library/DebugLib.h>
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| 20 | #include <Library/QemuFwCfgLib.h>
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| 21 |
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| 22 |
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| 23 | /**
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| 24 | Returns a boolean indicating if the firmware configuration interface
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| 25 | is available or not.
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| 26 |
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| 27 | This function may change fw_cfg state.
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| 28 |
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| 29 | @retval TRUE The interface is available
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| 30 | @retval FALSE The interface is not available
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| 31 |
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| 32 | **/
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| 33 | BOOLEAN
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| 34 | EFIAPI
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| 35 | QemuFwCfgIsAvailable (
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| 36 | VOID
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| 37 | )
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| 38 | {
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| 39 | UINT32 Signature;
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| 40 | UINT32 Revision;
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| 41 |
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| 42 | QemuFwCfgSelectItem (QemuFwCfgItemSignature);
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| 43 | Signature = QemuFwCfgRead32 ();
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| 44 | DEBUG ((EFI_D_INFO, "FW CFG Signature: 0x%x\n", Signature));
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| 45 | QemuFwCfgSelectItem (QemuFwCfgItemInterfaceVersion);
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| 46 | Revision = QemuFwCfgRead32 ();
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| 47 | DEBUG ((EFI_D_INFO, "FW CFG Revision: 0x%x\n", Revision));
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| 48 | if ((Signature != SIGNATURE_32 ('Q', 'E', 'M', 'U')) ||
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| 49 | (Revision < 1)
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| 50 | ) {
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| 51 | DEBUG ((EFI_D_INFO, "QemuFwCfg interface not supported.\n"));
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| 52 | return FALSE;
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| 53 | }
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| 54 |
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| 55 | DEBUG ((EFI_D_INFO, "QemuFwCfg interface is supported.\n"));
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| 56 | return TRUE;
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| 57 | }
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| 58 |
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| 59 |
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| 60 | /**
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| 61 | Returns a boolean indicating if the firmware configuration interface is
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| 62 | available for library-internal purposes.
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| 63 |
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| 64 | This function never changes fw_cfg state.
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| 65 |
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| 66 | @retval TRUE The interface is available internally.
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| 67 | @retval FALSE The interface is not available internally.
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| 68 | **/
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| 69 | BOOLEAN
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| 70 | EFIAPI
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| 71 | InternalQemuFwCfgIsAvailable (
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| 72 | VOID
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| 73 | )
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| 74 | {
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| 75 | //
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| 76 | // We always return TRUE, because the consumer of this library ought to have
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| 77 | // called QemuFwCfgIsAvailable before making other calls which would hit this
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| 78 | // path.
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| 79 | //
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| 80 | return TRUE;
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| 81 | }
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