| Vishal Bhoj | 82c8071 | 2015-12-15 21:13:33 +0530 | [diff] [blame] | 1 | /** @file
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| 2 |
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| 3 | Stateful and implicitly initialized fw_cfg library implementation.
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| 4 |
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| 5 | Copyright (C) 2013, Red Hat, Inc.
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| 6 | Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>
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| 7 |
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| 8 | This program and the accompanying materials are licensed and made available
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| 9 | under the terms and conditions of the BSD License which accompanies this
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| 10 | distribution. The full text of the license may be found at
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| 11 | http://opensource.org/licenses/bsd-license.php
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| 12 |
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| 13 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
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| 14 | WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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| 15 | **/
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| 16 |
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| 17 | #include <Library/DebugLib.h>
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| 18 | #include <Library/QemuFwCfgLib.h>
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| 19 |
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| 20 | STATIC BOOLEAN mQemuFwCfgSupported = FALSE;
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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 | return InternalQemuFwCfgIsAvailable ();
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| 40 | }
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| 41 |
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| 42 |
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| 43 | RETURN_STATUS
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| 44 | EFIAPI
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| 45 | QemuFwCfgInitialize (
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| 46 | VOID
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| 47 | )
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| 48 | {
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| 49 | UINT32 Signature;
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| 50 | UINT32 Revision;
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| 51 |
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| 52 | //
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| 53 | // Enable the access routines while probing to see if it is supported.
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| 54 | //
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| 55 | mQemuFwCfgSupported = TRUE;
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| 56 |
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| 57 | QemuFwCfgSelectItem (QemuFwCfgItemSignature);
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| 58 | Signature = QemuFwCfgRead32 ();
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| 59 | DEBUG ((EFI_D_INFO, "FW CFG Signature: 0x%x\n", Signature));
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| 60 | QemuFwCfgSelectItem (QemuFwCfgItemInterfaceVersion);
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| 61 | Revision = QemuFwCfgRead32 ();
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| 62 | DEBUG ((EFI_D_INFO, "FW CFG Revision: 0x%x\n", Revision));
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| 63 | if ((Signature != SIGNATURE_32 ('Q', 'E', 'M', 'U')) ||
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| 64 | (Revision < 1)
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| 65 | ) {
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| 66 | DEBUG ((EFI_D_INFO, "QemuFwCfg interface not supported.\n"));
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| 67 | mQemuFwCfgSupported = FALSE;
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| 68 | return RETURN_SUCCESS;
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| 69 | }
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| 70 |
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| 71 | DEBUG ((EFI_D_INFO, "QemuFwCfg interface is supported.\n"));
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| 72 | return RETURN_SUCCESS;
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| 73 | }
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| 74 |
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| 75 |
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| 76 | /**
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| 77 | Returns a boolean indicating if the firmware configuration interface is
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| 78 | available for library-internal purposes.
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| 79 |
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| 80 | This function never changes fw_cfg state.
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| 81 |
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| 82 | @retval TRUE The interface is available internally.
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| 83 | @retval FALSE The interface is not available internally.
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| 84 | **/
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| 85 | BOOLEAN
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| 86 | EFIAPI
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| 87 | InternalQemuFwCfgIsAvailable (
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| 88 | VOID
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| 89 | )
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| 90 | {
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| 91 | return mQemuFwCfgSupported;
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| 92 | }
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