summaryrefslogtreecommitdiffstats
path: root/drivers/pci/pcie/aer/ecrc.c
blob: ece97df4df6d1e8ccfceb32ee240c1d74c4af05d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
/*
 *    Enables/disables PCIe ECRC checking.
 *
 *    (C) Copyright 2009 Hewlett-Packard Development Company, L.P.
 *    Andrew Patterson <andrew.patterson@hp.com>
 *
 *    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; version 2 of the License.
 *
 *    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., 59 Temple Place, Suite 330, Boston, MA
 *    02111-1307, USA.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/pci.h>
#include <linux/pci_regs.h>
#include <linux/errno.h>
#include "../../pci.h"

#define ECRC_POLICY_DEFAULT 0		/* ECRC set by BIOS */
#define ECRC_POLICY_OFF     1		/* ECRC off for performance */
#define ECRC_POLICY_ON      2		/* ECRC on for data integrity */

static int ecrc_policy = ECRC_POLICY_DEFAULT;

static const char *ecrc_policy_str[] = {
	[ECRC_POLICY_DEFAULT] = "bios",
	[ECRC_POLICY_OFF] = "off",
	[ECRC_POLICY_ON] = "on"
};

/**
 * enable_ercr_checking - enable PCIe ECRC checking for a device
 * @dev: the PCI device
 *
 * Returns 0 on success, or negative on failure.
 */
static int enable_ecrc_checking(struct pci_dev *dev)
{
	int pos;
	u32 reg32;

	if (!dev->is_pcie)
		return -ENODEV;

	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
	if (!pos)
		return -ENODEV;

	pci_read_config_dword(dev, pos + PCI_ERR_CAP, &reg32);
	if (reg32 & PCI_ERR_CAP_ECRC_GENC)
		reg32 |= PCI_ERR_CAP_ECRC_GENE;
	if (reg32 & PCI_ERR_CAP_ECRC_CHKC)
		reg32 |= PCI_ERR_CAP_ECRC_CHKE;
	pci_write_config_dword(dev, pos + PCI_ERR_CAP, reg32);

	return 0;
}

/**
 * disable_ercr_checking - disables PCIe ECRC checking for a device
 * @dev: the PCI device
 *
 * Returns 0 on success, or negative on failure.
 */
static int disable_ecrc_checking(struct pci_dev *dev)
{
	int pos;
	u32 reg32;

	if (!dev->is_pcie)
		return -ENODEV;

	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
	if (!pos)
		return -ENODEV;

	pci_read_config_dword(dev, pos + PCI_ERR_CAP, &reg32);
	reg32 &= ~(PCI_ERR_CAP_ECRC_GENE | PCI_ERR_CAP_ECRC_CHKE);
	pci_write_config_dword(dev, pos + PCI_ERR_CAP, reg32);

	return 0;
}

/**
 * pcie_set_ecrc_checking - set/unset PCIe ECRC checking for a device based on global policy
 * @dev: the PCI device
 */
void pcie_set_ecrc_checking(struct pci_dev *dev)
{
	switch (ecrc_policy) {
	case ECRC_POLICY_DEFAULT:
		return;
	case ECRC_POLICY_OFF:
		disable_ecrc_checking(dev);
		break;
	case ECRC_POLICY_ON:
		enable_ecrc_checking(dev);;
		break;
	default:
		return;
	}
}

/**
 * pcie_ecrc_get_policy - parse kernel command-line ecrc option
 */
void pcie_ecrc_get_policy(char *str)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(ecrc_policy_str); i++)
		if (!strncmp(str, ecrc_policy_str[i],
			     strlen(ecrc_policy_str[i])))
			break;
	if (i >= ARRAY_SIZE(ecrc_policy_str))
		return;

	ecrc_policy = i;
}
OpenPOWER on IntegriCloud