linux_devmem.c revision 49310723 
1/*
2 * (C) Copyright IBM Corporation 2007
3 * All Rights Reserved.
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * on the rights to use, copy, modify, merge, publish, distribute, sub
9 * license, and/or sell copies of the Software, and to permit persons to whom
10 * the Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice (including the next
13 * paragraph) shall be included in all copies or substantial portions of the
14 * Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL
19 * IBM AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22 * DEALINGS IN THE SOFTWARE.
23 */
24
25/**
26 * \file linux_devmem.c
27 * Access PCI subsystem using Linux's the old /dev/mem interface.
28 *
29 * \note
30 * This is currently just a skeleton.  It only includes the /dev/mem based
31 * function for reading the device ROM.
32 *
33 * \author Ian Romanick <idr@us.ibm.com>
34 */
35#ifdef HAVE_CONFIG_H
36#include "config.h"
37#endif
38
39#include <stdlib.h>
40#include <string.h>
41#include <stdio.h>
42#include <unistd.h>
43#include <sys/types.h>
44#include <sys/stat.h>
45#include <fcntl.h>
46#include <sys/mman.h>
47#include <dirent.h>
48#include <errno.h>
49
50#include "pciaccess.h"
51#include "pciaccess_private.h"
52#include "linux_devmem.h"
53
54/**
55 * Read a device's expansion ROM using /dev/mem.
56 *
57 * \note
58 * This function could probably be used, as-is, on other platforms that have
59 * a /dev/mem interface.
60 *
61 * \bugs
62 * Before using the VGA special case code, this function should check that
63 * VGA access are routed to the device.  Right?
64 */
65_pci_hidden int
66pci_device_linux_devmem_read_rom(struct pci_device *dev, void *buffer)
67{
68    struct pci_device_private *priv = (struct pci_device_private *) dev;
69    int fd;
70    int err = 0;
71    uint32_t rom_base_tmp;
72    pciaddr_t rom_base;
73    pciaddr_t rom_size;
74    int PCI_ROM;
75
76
77    /* Handle some special cases of legacy devices.
78     */
79    if (priv->base.rom_size == 0) {
80	/* VGA ROMs are supposed to be at 0xC0000.
81	 */
82	if ((priv->base.device_class & 0x00ffff00) == 0x000030000) {
83	    rom_base = 0x000C0000;
84	    rom_size = 0x00010000;
85	    PCI_ROM = 0;
86	}
87	else {
88	    /* "Function not implemented."
89	     */
90	    return ENOSYS;
91	}
92    }
93    else {
94	rom_base = priv->rom_base;
95	rom_size = priv->base.rom_size;
96	PCI_ROM = 1;
97    }
98
99
100
101    /* Enable the device's ROM.
102     */
103    if (PCI_ROM) {
104	err = pci_device_cfg_read_u32(& priv->base, & rom_base_tmp, 48);
105	if (err) {
106	    return err;
107	}
108
109	if ((rom_base_tmp & 0x000000001) == 0) {
110	    err = pci_device_cfg_write_u32(& priv->base,
111					   rom_base_tmp | 1, 48);
112	    if (err) {
113		return err;
114	    }
115	}
116    }
117
118
119    /* Read the portion of /dev/mem that corresponds to the device's ROM.
120     */
121    fd = open("/dev/mem", O_RDONLY, 0);
122    if (fd < 0) {
123	err = errno;
124    }
125    else {
126	size_t bytes;
127
128	for (bytes = 0; bytes < rom_size; /* empty */) {
129	    const ssize_t got = pread(fd, buffer, rom_size - bytes,
130				      rom_base + bytes);
131	    if (got == -1) {
132		err = errno;
133		break;
134	    }
135
136	    bytes += got;
137	}
138
139	close(fd);
140    }
141
142
143    /* Disable the device's ROM.
144     */
145    if (PCI_ROM && ((rom_base_tmp & 0x000000001) == 0)) {
146	const int tmp_err = pci_device_cfg_write_u32(& priv->base,
147						     rom_base_tmp, 48);
148
149	/* Prefer to return the first error that occurred.
150	 */
151	if (err == 0) {
152	    err = tmp_err;
153	}
154    }
155
156    return err;
157}
158