comedi_pci.h revision a9f23e00c17567cc4b7ce50cd07226f7bfb70da6 
1/*
2    comedi/drivers/comedi_pci.h
3    Various PCI functions for drivers.
4
5    Copyright (C) 2007 MEV Ltd. <http://www.mev.co.uk/>
6
7    COMEDI - Linux Control and Measurement Device Interface
8    Copyright (C) 2000 David A. Schleef <ds@schleef.org>
9
10    This program is free software; you can redistribute it and/or modify
11    it under the terms of the GNU General Public License as published by
12    the Free Software Foundation; either version 2 of the License, or
13    (at your option) any later version.
14
15    This program is distributed in the hope that it will be useful,
16    but WITHOUT ANY WARRANTY; without even the implied warranty of
17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18    GNU General Public License for more details.
19
20    You should have received a copy of the GNU General Public License
21    along with this program; if not, write to the Free Software
22    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23
24*/
25
26#ifndef _COMEDI_PCI_H_
27#define _COMEDI_PCI_H_
28
29#include <linux/version.h>
30#include <linux/pci.h>
31
32#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,20)
33#define PCI_ENABLE_IS_REFCOUNTED
34#endif
35
36/*
37 * Enables PCI device without requesting regions.  Just a simple wrapper
38 * for pci_enable_device().
39 */
40static inline int comedi_pci_enable_no_regions(struct pci_dev *pdev)
41{
42	return pci_enable_device(pdev);
43}
44
45/*
46 * Called to disable PCI device if PCI device has been enabled, but
47 * PCI regions have not been reserved.
48 *
49 * It only disables the PCI device if the kernel supports reference
50 * counting of PCI enables, otherwise it might stop the device working
51 * in another driver instance.
52 */
53static inline void comedi_pci_disable_no_regions(struct pci_dev *pdev)
54{
55#ifdef PCI_ENABLE_IS_REFCOUNTED
56	pci_disable_device(pdev);
57#endif
58}
59
60/*
61 * Enable the PCI device and request the regions.
62 */
63static inline int comedi_pci_enable(struct pci_dev *pdev, const char *res_name)
64{
65	int rc;
66
67	rc = pci_enable_device(pdev);
68	if (rc < 0) {
69		return rc;
70	}
71	rc = pci_request_regions(pdev, res_name);
72	if (rc < 0) {
73		comedi_pci_disable_no_regions(pdev);
74	}
75	return rc;
76}
77
78/*
79 * Release the regions and disable the PCI device.
80 *
81 * This must be matched with a previous successful call to comedi_pci_enable().
82 */
83static inline void comedi_pci_disable(struct pci_dev *pdev)
84{
85	pci_release_regions(pdev);
86	pci_disable_device(pdev);
87}
88
89#endif
90