linux_devmem.c revision cad31331 
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
36#define _GNU_SOURCE
37
38#include <stdlib.h>
39#include <string.h>
40#include <stdio.h>
41#include <unistd.h>
42#include <sys/types.h>
43#include <sys/stat.h>
44#include <fcntl.h>
45#include <sys/mman.h>
46#include <dirent.h>
47#include <errno.h>
48
49#include "pciaccess.h"
50#include "pciaccess_private.h"
51#include "linux_devmem.h"
52
53/**
54 * Read a device's expansion ROM using /dev/mem.
55 *
56 * \note
57 * This function could probably be used, as-is, on other platforms that have
58 * a /dev/mem interface.
59 *
60 * \bugs
61 * Before using the VGA special case code, this function should check that
62 * VGA access are routed to the device.  Right?
63 */
64_pci_hidden int
65pci_device_linux_devmem_read_rom(struct pci_device *dev, void *buffer)
66{
67    struct pci_device_private *priv = (struct pci_device_private *) dev;
68    int fd;
69    int err = 0;
70    uint32_t rom_base_tmp;
71    pciaddr_t rom_base;
72    pciaddr_t rom_size;
73    int PCI_ROM;
74
75
76    /* Handle some special cases of legacy devices.
77     */
78    if (priv->base.rom_size == 0) {
79	/* VGA ROMs are supposed to be at 0xC0000.
80	 */
81	if ((priv->base.device_class & 0x00ffff00) == 0x000030000) {
82	    rom_base = 0x000C0000;
83	    rom_size = 0x00010000;
84	    PCI_ROM = 0;
85	}
86	else {
87	    /* "Function not implemented."
88	     */
89	    return ENOSYS;
90	}
91    }
92    else {
93	rom_base = priv->rom_base;
94	rom_size = priv->base.rom_size;
95	PCI_ROM = 1;
96    }
97
98
99
100    /* Enable the device's ROM.
101     */
102    if (PCI_ROM) {
103	err = pci_device_cfg_read_u32(& priv->base, & rom_base_tmp, 48);
104	if (err) {
105	    return err;
106	}
107
108	if ((rom_base_tmp & 0x000000001) == 0) {
109	    err = pci_device_cfg_write_u32(& priv->base,
110					   rom_base_tmp | 1, 48);
111	    if (err) {
112		return err;
113	    }
114	}
115    }
116
117
118    /* Read the portion of /dev/mem that corresponds to the device's ROM.
119     */
120    fd = open("/dev/mem", O_RDONLY, 0);
121    if (fd < 0) {
122	err = errno;
123    }
124    else {
125	size_t bytes;
126
127	for (bytes = 0; bytes < rom_size; /* empty */) {
128	    const ssize_t got = pread(fd, buffer, rom_size - bytes,
129				      rom_base + bytes);
130	    if (got == -1) {
131		err = errno;
132		break;
133	    }
134
135	    bytes += got;
136	}
137
138	close(fd);
139    }
140
141
142    /* Disable the device's ROM.
143     */
144    if (PCI_ROM && ((rom_base_tmp & 0x000000001) == 0)) {
145	const int tmp_err = pci_device_cfg_write_u32(& priv->base,
146						     rom_base_tmp, 48);
147
148	/* Prefer to return the first error that occurred.
149	 */
150	if (err == 0) {
151	    err = tmp_err;
152	}
153    }
154
155    return err;
156}
157