summaryrefslogtreecommitdiff
path: root/drivers/pci/ats.c
blob: 5ceff3e16e1be0ce9457b65d21f6afe326b598b4 (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
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
/*
 * drivers/pci/ats.c
 *
 * Copyright (C) 2009 Intel Corporation, Yu Zhao <yu.zhao@intel.com>
 *
 * PCI Express I/O Virtualization (IOV) support.
 *   Address Translation Service 1.0
 */

#include <linux/pci-ats.h>
#include <linux/pci.h>

#include "pci.h"

static int ats_alloc_one(struct pci_dev *dev, int ps)
{
	int pos;
	u16 cap;
	struct pci_ats *ats;

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

	ats = kzalloc(sizeof(*ats), GFP_KERNEL);
	if (!ats)
		return -ENOMEM;

	ats->pos = pos;
	ats->stu = ps;
	pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap);
	ats->qdep = PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) :
					    PCI_ATS_MAX_QDEP;
	dev->ats = ats;

	return 0;
}

static void ats_free_one(struct pci_dev *dev)
{
	kfree(dev->ats);
	dev->ats = NULL;
}

/**
 * pci_enable_ats - enable the ATS capability
 * @dev: the PCI device
 * @ps: the IOMMU page shift
 *
 * Returns 0 on success, or negative on failure.
 */
int pci_enable_ats(struct pci_dev *dev, int ps)
{
	int rc;
	u16 ctrl;

	BUG_ON(dev->ats && dev->ats->is_enabled);

	if (ps < PCI_ATS_MIN_STU)
		return -EINVAL;

	if (dev->is_physfn || dev->is_virtfn) {
		struct pci_dev *pdev = dev->is_physfn ? dev : dev->physfn;

		mutex_lock(&pdev->sriov->lock);
		if (pdev->ats)
			rc = pdev->ats->stu == ps ? 0 : -EINVAL;
		else
			rc = ats_alloc_one(pdev, ps);

		if (!rc)
			pdev->ats->ref_cnt++;
		mutex_unlock(&pdev->sriov->lock);
		if (rc)
			return rc;
	}

	if (!dev->is_physfn) {
		rc = ats_alloc_one(dev, ps);
		if (rc)
			return rc;
	}

	ctrl = PCI_ATS_CTRL_ENABLE;
	if (!dev->is_virtfn)
		ctrl |= PCI_ATS_CTRL_STU(ps - PCI_ATS_MIN_STU);
	pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);

	dev->ats->is_enabled = 1;

	return 0;
}
EXPORT_SYMBOL_GPL(pci_enable_ats);

/**
 * pci_disable_ats - disable the ATS capability
 * @dev: the PCI device
 */
void pci_disable_ats(struct pci_dev *dev)
{
	u16 ctrl;

	BUG_ON(!dev->ats || !dev->ats->is_enabled);

	pci_read_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, &ctrl);
	ctrl &= ~PCI_ATS_CTRL_ENABLE;
	pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);

	dev->ats->is_enabled = 0;

	if (dev->is_physfn || dev->is_virtfn) {
		struct pci_dev *pdev = dev->is_physfn ? dev : dev->physfn;

		mutex_lock(&pdev->sriov->lock);
		pdev->ats->ref_cnt--;
		if (!pdev->ats->ref_cnt)
			ats_free_one(pdev);
		mutex_unlock(&pdev->sriov->lock);
	}

	if (!dev->is_physfn)
		ats_free_one(dev);
}
EXPORT_SYMBOL_GPL(pci_disable_ats);

/**
 * pci_ats_queue_depth - query the ATS Invalidate Queue Depth
 * @dev: the PCI device
 *
 * Returns the queue depth on success, or negative on failure.
 *
 * The ATS spec uses 0 in the Invalidate Queue Depth field to
 * indicate that the function can accept 32 Invalidate Request.
 * But here we use the `real' values (i.e. 1~32) for the Queue
 * Depth; and 0 indicates the function shares the Queue with
 * other functions (doesn't exclusively own a Queue).
 */
int pci_ats_queue_depth(struct pci_dev *dev)
{
	int pos;
	u16 cap;

	if (dev->is_virtfn)
		return 0;

	if (dev->ats)
		return dev->ats->qdep;

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

	pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap);

	return PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) :
				       PCI_ATS_MAX_QDEP;
}
EXPORT_SYMBOL_GPL(pci_ats_queue_depth);