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[pci] Add generic configuration space backup/restore facility
Some devices can only be reset via a mechanism that also resets the card's PCI core, thus necessitating a backup and restore of all or part of the PCI configuration space across a reset.
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Michael Brown
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Oct 14, 2009
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/* | ||
* Copyright (C) 2009 Michael Brown <mbrown@fensystems.co.uk>. | ||
* | ||
* This program is free software; you can redistribute it and/or | ||
* modify it under the terms of the GNU General Public License as | ||
* published by the Free Software Foundation; either version 2 of the | ||
* License, or any later version. | ||
* | ||
* This program is distributed in the hope that it will be useful, but | ||
* WITHOUT ANY WARRANTY; without even the implied warranty of | ||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
* General Public License for more details. | ||
* | ||
* You should have received a copy of the GNU General Public License | ||
* along with this program; if not, write to the Free Software | ||
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | ||
*/ | ||
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FILE_LICENCE ( GPL2_OR_LATER ); | ||
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#include <stdint.h> | ||
#include <gpxe/pci.h> | ||
#include <gpxe/pcibackup.h> | ||
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/** @file | ||
* | ||
* PCI configuration space backup and restoration | ||
* | ||
*/ | ||
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/** | ||
* Check PCI configuration space offset against exclusion list | ||
* | ||
* @v pci PCI device | ||
* @v offset Offset within PCI configuration space | ||
* @v exclude PCI configuration space backup exclusion list, or NULL | ||
*/ | ||
static int | ||
pci_backup_excluded ( struct pci_device *pci, unsigned int offset, | ||
const uint8_t *exclude ) { | ||
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if ( ! exclude ) | ||
return 0; | ||
for ( ; *exclude != PCI_CONFIG_BACKUP_EXCLUDE_END ; exclude++ ) { | ||
if ( offset == *exclude ) { | ||
DBGC ( pci, "PCI %p skipping configuration offset " | ||
"%02x\n", pci, offset ); | ||
return 1; | ||
} | ||
} | ||
return 0; | ||
} | ||
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/** | ||
* Back up PCI configuration space | ||
* | ||
* @v pci PCI device | ||
* @v backup PCI configuration space backup | ||
* @v exclude PCI configuration space backup exclusion list, or NULL | ||
*/ | ||
void pci_backup ( struct pci_device *pci, struct pci_config_backup *backup, | ||
const uint8_t *exclude ) { | ||
unsigned int offset; | ||
uint32_t *dword; | ||
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for ( offset = 0, dword = backup->dwords ; offset < 0x100 ; | ||
offset += sizeof ( *dword ) , dword++ ) { | ||
if ( ! pci_backup_excluded ( pci, offset, exclude ) ) | ||
pci_read_config_dword ( pci, offset, dword ); | ||
} | ||
} | ||
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/** | ||
* Restore PCI configuration space | ||
* | ||
* @v pci PCI device | ||
* @v backup PCI configuration space backup | ||
* @v exclude PCI configuration space backup exclusion list, or NULL | ||
*/ | ||
void pci_restore ( struct pci_device *pci, struct pci_config_backup *backup, | ||
const uint8_t *exclude ) { | ||
unsigned int offset; | ||
uint32_t *dword; | ||
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for ( offset = 0, dword = backup->dwords ; offset < 0x100 ; | ||
offset += sizeof ( *dword ) , dword++ ) { | ||
if ( ! pci_backup_excluded ( pci, offset, exclude ) ) | ||
pci_write_config_dword ( pci, offset, *dword ); | ||
} | ||
} |
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#ifndef _GPXE_PCIBACKUP_H | ||
#define _GPXE_PCIBACKUP_H | ||
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/** @file | ||
* | ||
* PCI configuration space backup and restoration | ||
* | ||
*/ | ||
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FILE_LICENCE ( GPL2_OR_LATER ); | ||
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#include <stdint.h> | ||
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/** A PCI configuration space backup */ | ||
struct pci_config_backup { | ||
uint32_t dwords[64]; | ||
}; | ||
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/** PCI configuration space backup exclusion list end marker */ | ||
#define PCI_CONFIG_BACKUP_EXCLUDE_END 0xff | ||
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/** Define a PCI configuration space backup exclusion list */ | ||
#define PCI_CONFIG_BACKUP_EXCLUDE(...) \ | ||
{ __VA_ARGS__, PCI_CONFIG_BACKUP_EXCLUDE_END } | ||
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extern void pci_backup ( struct pci_device *pci, | ||
struct pci_config_backup *backup, | ||
const uint8_t *exclude ); | ||
extern void pci_restore ( struct pci_device *pci, | ||
struct pci_config_backup *backup, | ||
const uint8_t *exclude ); | ||
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#endif /* _GPXE_PCIBACKUP_H */ |