aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/uio/uio_hv_generic.c
blob: 48d5327d38d420d84f49d52aa9a904d2ee174d80 (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
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
/*
 * uio_hv_generic - generic UIO driver for VMBus
 *
 * Copyright (c) 2013-2016 Brocade Communications Systems, Inc.
 * Copyright (c) 2016, Microsoft Corporation.
 *
 *
 * This work is licensed under the terms of the GNU GPL, version 2.
 *
 * Since the driver does not declare any device ids, you must allocate
 * id and bind the device to the driver yourself.  For example:
 *
 * # echo "f8615163-df3e-46c5-913f-f2d2f965ed0e" \
 *    > /sys/bus/vmbus/drivers/uio_hv_generic
 * # echo -n vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3 \
 *    > /sys/bus/vmbus/drivers/hv_netvsc/unbind
 * # echo -n vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3 \
 *    > /sys/bus/vmbus/drivers/uio_hv_generic/bind
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/uio_driver.h>
#include <linux/netdevice.h>
#include <linux/if_ether.h>
#include <linux/skbuff.h>
#include <linux/hyperv.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>

#include "../hv/hyperv_vmbus.h"

#define DRIVER_VERSION	"0.02.0"
#define DRIVER_AUTHOR	"Stephen Hemminger <sthemmin at microsoft.com>"
#define DRIVER_DESC	"Generic UIO driver for VMBus devices"

/*
 * List of resources to be mapped to user space
 * can be extended up to MAX_UIO_MAPS(5) items
 */
enum hv_uio_map {
	TXRX_RING_MAP = 0,
	INT_PAGE_MAP,
	MON_PAGE_MAP,
};

#define HV_RING_SIZE	512

struct hv_uio_private_data {
	struct uio_info info;
	struct hv_device *device;
};

static int
hv_uio_mmap(struct uio_info *info, struct vm_area_struct *vma)
{
	int mi;

	if (vma->vm_pgoff >= MAX_UIO_MAPS)
		return -EINVAL;

	if (info->mem[vma->vm_pgoff].size == 0)
		return -EINVAL;

	mi = (int)vma->vm_pgoff;

	return remap_pfn_range(vma, vma->vm_start,
			info->mem[mi].addr >> PAGE_SHIFT,
			vma->vm_end - vma->vm_start, vma->vm_page_prot);
}

/*
 * This is the irqcontrol callback to be registered to uio_info.
 * It can be used to disable/enable interrupt from user space processes.
 *
 * @param info
 *  pointer to uio_info.
 * @param irq_state
 *  state value. 1 to enable interrupt, 0 to disable interrupt.
 */
static int
hv_uio_irqcontrol(struct uio_info *info, s32 irq_state)
{
	struct hv_uio_private_data *pdata = info->priv;
	struct hv_device *dev = pdata->device;

	dev->channel->inbound.ring_buffer->interrupt_mask = !irq_state;
	virt_mb();

	return 0;
}

/*
 * Callback from vmbus_event when something is in inbound ring.
 */
static void hv_uio_channel_cb(void *context)
{
	struct hv_uio_private_data *pdata = context;
	struct hv_device *dev = pdata->device;

	dev->channel->inbound.ring_buffer->interrupt_mask = 1;
	virt_mb();

	uio_event_notify(&pdata->info);
}

static int
hv_uio_probe(struct hv_device *dev,
	     const struct hv_vmbus_device_id *dev_id)
{
	struct hv_uio_private_data *pdata;
	int ret;

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

	ret = vmbus_open(dev->channel, HV_RING_SIZE * PAGE_SIZE,
			 HV_RING_SIZE * PAGE_SIZE, NULL, 0,
			 hv_uio_channel_cb, pdata);
	if (ret)
		goto fail;

	dev->channel->inbound.ring_buffer->interrupt_mask = 1;
	set_channel_read_mode(dev->channel, HV_CALL_DIRECT);

	/* Fill general uio info */
	pdata->info.name = "uio_hv_generic";
	pdata->info.version = DRIVER_VERSION;
	pdata->info.irqcontrol = hv_uio_irqcontrol;
	pdata->info.mmap = hv_uio_mmap;
	pdata->info.irq = UIO_IRQ_CUSTOM;

	/* mem resources */
	pdata->info.mem[TXRX_RING_MAP].name = "txrx_rings";
	pdata->info.mem[TXRX_RING_MAP].addr
		= virt_to_phys(dev->channel->ringbuffer_pages);
	pdata->info.mem[TXRX_RING_MAP].size
		= dev->channel->ringbuffer_pagecount * PAGE_SIZE;
	pdata->info.mem[TXRX_RING_MAP].memtype = UIO_MEM_LOGICAL;

	pdata->info.mem[INT_PAGE_MAP].name = "int_page";
	pdata->info.mem[INT_PAGE_MAP].addr =
		virt_to_phys(vmbus_connection.int_page);
	pdata->info.mem[INT_PAGE_MAP].size = PAGE_SIZE;
	pdata->info.mem[INT_PAGE_MAP].memtype = UIO_MEM_LOGICAL;

	pdata->info.mem[MON_PAGE_MAP].name = "monitor_pages";
	pdata->info.mem[MON_PAGE_MAP].addr =
		virt_to_phys(vmbus_connection.monitor_pages[1]);
	pdata->info.mem[MON_PAGE_MAP].size = PAGE_SIZE;
	pdata->info.mem[MON_PAGE_MAP].memtype = UIO_MEM_LOGICAL;

	pdata->info.priv = pdata;
	pdata->device = dev;

	ret = uio_register_device(&dev->device, &pdata->info);
	if (ret) {
		dev_err(&dev->device, "hv_uio register failed\n");
		goto fail_close;
	}

	hv_set_drvdata(dev, pdata);

	return 0;

fail_close:
	vmbus_close(dev->channel);
fail:
	kfree(pdata);

	return ret;
}

static int
hv_uio_remove(struct hv_device *dev)
{
	struct hv_uio_private_data *pdata = hv_get_drvdata(dev);

	if (!pdata)
		return 0;

	uio_unregister_device(&pdata->info);
	hv_set_drvdata(dev, NULL);
	vmbus_close(dev->channel);
	kfree(pdata);
	return 0;
}

static struct hv_driver hv_uio_drv = {
	.name = "uio_hv_generic",
	.id_table = NULL, /* only dynamic id's */
	.probe = hv_uio_probe,
	.remove = hv_uio_remove,
};

static int __init
hyperv_module_init(void)
{
	return vmbus_driver_register(&hv_uio_drv);
}

static void __exit
hyperv_module_exit(void)
{
	vmbus_driver_unregister(&hv_uio_drv);
}

module_init(hyperv_module_init);
module_exit(hyperv_module_exit);

MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);