1/*
  2 * uio_hv_generic - generic UIO driver for VMBus
  3 *
  4 * Copyright (c) 2013-2016 Brocade Communications Systems, Inc.
  5 * Copyright (c) 2016, Microsoft Corporation.
  6 *
  7 *
  8 * This work is licensed under the terms of the GNU GPL, version 2.
  9 *
 10 * Since the driver does not declare any device ids, you must allocate
 11 * id and bind the device to the driver yourself.  For example:
 12 *
 13 * Associate Network GUID with UIO device
 14 * # echo "f8615163-df3e-46c5-913f-f2d2f965ed0e" \
 15 *    > /sys/bus/vmbus/drivers/uio_hv_generic/new_id
 16 * Then rebind
 17 * # echo -n "ed963694-e847-4b2a-85af-bc9cfc11d6f3" \
 18 *    > /sys/bus/vmbus/drivers/hv_netvsc/unbind
 19 * # echo -n "ed963694-e847-4b2a-85af-bc9cfc11d6f3" \
 20 *    > /sys/bus/vmbus/drivers/uio_hv_generic/bind
 21 */
 22#define DEBUG 1
 23#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 24
 25#include <linux/device.h>
 26#include <linux/kernel.h>
 27#include <linux/module.h>
 28#include <linux/uio_driver.h>
 29#include <linux/netdevice.h>
 30#include <linux/if_ether.h>
 31#include <linux/skbuff.h>
 32#include <linux/hyperv.h>
 33#include <linux/vmalloc.h>
 34#include <linux/slab.h>
 35
 36#include "../hv/hyperv_vmbus.h"
 37
 38#define DRIVER_VERSION	"0.02.0"
 39#define DRIVER_AUTHOR	"Stephen Hemminger <sthemmin at microsoft.com>"
 40#define DRIVER_DESC	"Generic UIO driver for VMBus devices"
 41
 42#define HV_RING_SIZE	 512	/* pages */
 43#define SEND_BUFFER_SIZE (15 * 1024 * 1024)
 44#define RECV_BUFFER_SIZE (15 * 1024 * 1024)
 45
 46/*
 47 * List of resources to be mapped to user space
 48 * can be extended up to MAX_UIO_MAPS(5) items
 49 */
 50enum hv_uio_map {
 51	TXRX_RING_MAP = 0,
 52	INT_PAGE_MAP,
 53	MON_PAGE_MAP,
 54	RECV_BUF_MAP,
 55	SEND_BUF_MAP
 56};
 57
 58struct hv_uio_private_data {
 59	struct uio_info info;
 60	struct hv_device *device;
 61
 62	void	*recv_buf;
 63	u32	recv_gpadl;
 64	char	recv_name[32];	/* "recv_4294967295" */
 65
 66	void	*send_buf;
 67	u32	send_gpadl;
 68	char	send_name[32];
 69};
 70
 71/*
 72 * This is the irqcontrol callback to be registered to uio_info.
 73 * It can be used to disable/enable interrupt from user space processes.
 74 *
 75 * @param info
 76 *  pointer to uio_info.
 77 * @param irq_state
 78 *  state value. 1 to enable interrupt, 0 to disable interrupt.
 79 */
 80static int
 81hv_uio_irqcontrol(struct uio_info *info, s32 irq_state)
 82{
 83	struct hv_uio_private_data *pdata = info->priv;
 84	struct hv_device *dev = pdata->device;
 85
 86	dev->channel->inbound.ring_buffer->interrupt_mask = !irq_state;
 87	virt_mb();
 88
 89	return 0;
 90}
 91
 92/*
 93 * Callback from vmbus_event when something is in inbound ring.
 94 */
 95static void hv_uio_channel_cb(void *context)
 96{
 97	struct vmbus_channel *chan = context;
 98	struct hv_device *hv_dev = chan->device_obj;
 99	struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev);
100
101	chan->inbound.ring_buffer->interrupt_mask = 1;
102	virt_mb();
103
104	uio_event_notify(&pdata->info);
105}
106
107/*
108 * Callback from vmbus_event when channel is rescinded.
109 */
110static void hv_uio_rescind(struct vmbus_channel *channel)
111{
112	struct hv_device *hv_dev = channel->primary_channel->device_obj;
113	struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev);
114
115	/*
116	 * Turn off the interrupt file handle
117	 * Next read for event will return -EIO
118	 */
119	pdata->info.irq = 0;
120
121	/* Wake up reader */
122	uio_event_notify(&pdata->info);
123}
124
125/* Sysfs API to allow mmap of the ring buffers
126 * The ring buffer is allocated as contiguous memory by vmbus_open
127 */
128static int hv_uio_ring_mmap(struct file *filp, struct kobject *kobj,
129			    struct bin_attribute *attr,
130			    struct vm_area_struct *vma)
131{
132	struct vmbus_channel *channel
133		= container_of(kobj, struct vmbus_channel, kobj);
134	struct hv_device *dev = channel->primary_channel->device_obj;
135	u16 q_idx = channel->offermsg.offer.sub_channel_index;
136
137	dev_dbg(&dev->device, "mmap channel %u pages %#lx at %#lx\n",
138		q_idx, vma_pages(vma), vma->vm_pgoff);
139
140	return vm_iomap_memory(vma, virt_to_phys(channel->ringbuffer_pages),
141			       channel->ringbuffer_pagecount << PAGE_SHIFT);
142}
143
144static const struct bin_attribute ring_buffer_bin_attr = {
145	.attr = {
146		.name = "ring",
147		.mode = 0600,
148	},
149	.size = 2 * HV_RING_SIZE * PAGE_SIZE,
150	.mmap = hv_uio_ring_mmap,
151};
152
153/* Callback from VMBUS subsystem when new channel created. */
154static void
155hv_uio_new_channel(struct vmbus_channel *new_sc)
156{
157	struct hv_device *hv_dev = new_sc->primary_channel->device_obj;
158	struct device *device = &hv_dev->device;
159	const size_t ring_bytes = HV_RING_SIZE * PAGE_SIZE;
160	int ret;
161
162	/* Create host communication ring */
163	ret = vmbus_open(new_sc, ring_bytes, ring_bytes, NULL, 0,
164			 hv_uio_channel_cb, new_sc);
165	if (ret) {
166		dev_err(device, "vmbus_open subchannel failed: %d\n", ret);
167		return;
168	}
169
170	/* Disable interrupts on sub channel */
171	new_sc->inbound.ring_buffer->interrupt_mask = 1;
172	set_channel_read_mode(new_sc, HV_CALL_ISR);
173
174	ret = sysfs_create_bin_file(&new_sc->kobj, &ring_buffer_bin_attr);
175	if (ret) {
176		dev_err(device, "sysfs create ring bin file failed; %d\n", ret);
177		vmbus_close(new_sc);
178	}
179}
180
181static void
182hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata)
183{
184	if (pdata->send_gpadl)
185		vmbus_teardown_gpadl(dev->channel, pdata->send_gpadl);
186	vfree(pdata->send_buf);
187
188	if (pdata->recv_gpadl)
189		vmbus_teardown_gpadl(dev->channel, pdata->recv_gpadl);
190	vfree(pdata->recv_buf);
191}
192
193static int
194hv_uio_probe(struct hv_device *dev,
195	     const struct hv_vmbus_device_id *dev_id)
196{
197	struct hv_uio_private_data *pdata;
198	int ret;
199
200	pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
201	if (!pdata)
202		return -ENOMEM;
203
204	ret = vmbus_open(dev->channel, HV_RING_SIZE * PAGE_SIZE,
205			 HV_RING_SIZE * PAGE_SIZE, NULL, 0,
206			 hv_uio_channel_cb, dev->channel);
207	if (ret)
208		goto fail;
209
210	/* Communicating with host has to be via shared memory not hypercall */
211	if (!dev->channel->offermsg.monitor_allocated) {
212		dev_err(&dev->device, "vmbus channel requires hypercall\n");
213		ret = -ENOTSUPP;
214		goto fail_close;
215	}
216
217	dev->channel->inbound.ring_buffer->interrupt_mask = 1;
218	set_channel_read_mode(dev->channel, HV_CALL_ISR);
219
220	/* Fill general uio info */
221	pdata->info.name = "uio_hv_generic";
222	pdata->info.version = DRIVER_VERSION;
223	pdata->info.irqcontrol = hv_uio_irqcontrol;
224	pdata->info.irq = UIO_IRQ_CUSTOM;
225
226	/* mem resources */
227	pdata->info.mem[TXRX_RING_MAP].name = "txrx_rings";
228	pdata->info.mem[TXRX_RING_MAP].addr
229		= (uintptr_t)dev->channel->ringbuffer_pages;
230	pdata->info.mem[TXRX_RING_MAP].size
231		= dev->channel->ringbuffer_pagecount << PAGE_SHIFT;
232	pdata->info.mem[TXRX_RING_MAP].memtype = UIO_MEM_LOGICAL;
233
234	pdata->info.mem[INT_PAGE_MAP].name = "int_page";
235	pdata->info.mem[INT_PAGE_MAP].addr
236		= (uintptr_t)vmbus_connection.int_page;
237	pdata->info.mem[INT_PAGE_MAP].size = PAGE_SIZE;
238	pdata->info.mem[INT_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
239
240	pdata->info.mem[MON_PAGE_MAP].name = "monitor_page";
241	pdata->info.mem[MON_PAGE_MAP].addr
242		= (uintptr_t)vmbus_connection.monitor_pages[1];
243	pdata->info.mem[MON_PAGE_MAP].size = PAGE_SIZE;
244	pdata->info.mem[MON_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
245
246	pdata->recv_buf = vzalloc(RECV_BUFFER_SIZE);
247	if (pdata->recv_buf == NULL) {
248		ret = -ENOMEM;
249		goto fail_close;
250	}
251
252	ret = vmbus_establish_gpadl(dev->channel, pdata->recv_buf,
253				    RECV_BUFFER_SIZE, &pdata->recv_gpadl);
254	if (ret)
255		goto fail_close;
256
257	/* put Global Physical Address Label in name */
258	snprintf(pdata->recv_name, sizeof(pdata->recv_name),
259		 "recv:%u", pdata->recv_gpadl);
260	pdata->info.mem[RECV_BUF_MAP].name = pdata->recv_name;
261	pdata->info.mem[RECV_BUF_MAP].addr
262		= (uintptr_t)pdata->recv_buf;
263	pdata->info.mem[RECV_BUF_MAP].size = RECV_BUFFER_SIZE;
264	pdata->info.mem[RECV_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
265
266
267	pdata->send_buf = vzalloc(SEND_BUFFER_SIZE);
268	if (pdata->send_buf == NULL) {
269		ret = -ENOMEM;
270		goto fail_close;
271	}
272
273	ret = vmbus_establish_gpadl(dev->channel, pdata->send_buf,
274				    SEND_BUFFER_SIZE, &pdata->send_gpadl);
275	if (ret)
276		goto fail_close;
277
278	snprintf(pdata->send_name, sizeof(pdata->send_name),
279		 "send:%u", pdata->send_gpadl);
280	pdata->info.mem[SEND_BUF_MAP].name = pdata->send_name;
281	pdata->info.mem[SEND_BUF_MAP].addr
282		= (uintptr_t)pdata->send_buf;
283	pdata->info.mem[SEND_BUF_MAP].size = SEND_BUFFER_SIZE;
284	pdata->info.mem[SEND_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
285
286	pdata->info.priv = pdata;
287	pdata->device = dev;
288
289	ret = uio_register_device(&dev->device, &pdata->info);
290	if (ret) {
291		dev_err(&dev->device, "hv_uio register failed\n");
292		goto fail_close;
293	}
294
295	vmbus_set_chn_rescind_callback(dev->channel, hv_uio_rescind);
296	vmbus_set_sc_create_callback(dev->channel, hv_uio_new_channel);
297
298	ret = sysfs_create_bin_file(&dev->channel->kobj, &ring_buffer_bin_attr);
299	if (ret)
300		dev_notice(&dev->device,
301			   "sysfs create ring bin file failed; %d\n", ret);
302
303	hv_set_drvdata(dev, pdata);
304
305	return 0;
306
307fail_close:
308	hv_uio_cleanup(dev, pdata);
309	vmbus_close(dev->channel);
310fail:
311	kfree(pdata);
312
313	return ret;
314}
315
316static int
317hv_uio_remove(struct hv_device *dev)
318{
319	struct hv_uio_private_data *pdata = hv_get_drvdata(dev);
320
321	if (!pdata)
322		return 0;
323
324	uio_unregister_device(&pdata->info);
325	hv_uio_cleanup(dev, pdata);
326	hv_set_drvdata(dev, NULL);
327	vmbus_close(dev->channel);
328	kfree(pdata);
329	return 0;
330}
331
332static struct hv_driver hv_uio_drv = {
333	.name = "uio_hv_generic",
334	.id_table = NULL, /* only dynamic id's */
335	.probe = hv_uio_probe,
336	.remove = hv_uio_remove,
337};
338
339static int __init
340hyperv_module_init(void)
341{
342	return vmbus_driver_register(&hv_uio_drv);
343}
344
345static void __exit
346hyperv_module_exit(void)
347{
348	vmbus_driver_unregister(&hv_uio_drv);
349}
350
351module_init(hyperv_module_init);
352module_exit(hyperv_module_exit);
353
354MODULE_VERSION(DRIVER_VERSION);
355MODULE_LICENSE("GPL v2");
356MODULE_AUTHOR(DRIVER_AUTHOR);
357MODULE_DESCRIPTION(DRIVER_DESC);