1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2018, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
4  * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
5  *
6  * VirtIO is a virtualization standard for network and disk device drivers
7  * where just the guest's device driver "knows" it is running in a virtual
8  * environment, and cooperates with the hypervisor. This enables guests to
9  * get high performance network and disk operations, and gives most of the
10  * performance benefits of paravirtualization. In the U-Boot case, the guest
11  * is U-Boot itself, while the virtual environment are normally QEMU targets
12  * like ARM, RISC-V and x86.
13  *
14  * See http://docs.oasis-open.org/virtio/virtio/v1.0/virtio-v1.0.pdf for
15  * the VirtIO specification v1.0.
16  */
17 
18 #include <common.h>
19 #include <dm.h>
20 #include <virtio_types.h>
21 #include <virtio.h>
22 #include <dm/lists.h>
23 
24 static const char *const virtio_drv_name[VIRTIO_ID_MAX_NUM] = {
25 	[VIRTIO_ID_NET]		= VIRTIO_NET_DRV_NAME,
26 	[VIRTIO_ID_BLOCK]	= VIRTIO_BLK_DRV_NAME,
27 };
28 
29 int virtio_get_config(struct udevice *vdev, unsigned int offset,
30 		      void *buf, unsigned int len)
31 {
32 	struct dm_virtio_ops *ops;
33 
34 	ops = virtio_get_ops(vdev->parent);
35 
36 	return ops->get_config(vdev->parent, offset, buf, len);
37 }
38 
39 int virtio_set_config(struct udevice *vdev, unsigned int offset,
40 		      void *buf, unsigned int len)
41 {
42 	struct dm_virtio_ops *ops;
43 
44 	ops = virtio_get_ops(vdev->parent);
45 
46 	return ops->set_config(vdev->parent, offset, buf, len);
47 }
48 
49 int virtio_generation(struct udevice *vdev, u32 *counter)
50 {
51 	struct dm_virtio_ops *ops;
52 
53 	ops = virtio_get_ops(vdev->parent);
54 	if (!ops->generation)
55 		return -ENOSYS;
56 
57 	return ops->generation(vdev->parent, counter);
58 }
59 
60 int virtio_get_status(struct udevice *vdev, u8 *status)
61 {
62 	struct dm_virtio_ops *ops;
63 
64 	ops = virtio_get_ops(vdev->parent);
65 
66 	return ops->get_status(vdev->parent, status);
67 }
68 
69 int virtio_set_status(struct udevice *vdev, u8 status)
70 {
71 	struct dm_virtio_ops *ops;
72 
73 	ops = virtio_get_ops(vdev->parent);
74 
75 	return ops->set_status(vdev->parent, status);
76 }
77 
78 int virtio_reset(struct udevice *vdev)
79 {
80 	struct dm_virtio_ops *ops;
81 
82 	ops = virtio_get_ops(vdev->parent);
83 
84 	return ops->reset(vdev->parent);
85 }
86 
87 int virtio_get_features(struct udevice *vdev, u64 *features)
88 {
89 	struct dm_virtio_ops *ops;
90 
91 	ops = virtio_get_ops(vdev->parent);
92 
93 	return ops->get_features(vdev->parent, features);
94 }
95 
96 int virtio_set_features(struct udevice *vdev)
97 {
98 	struct dm_virtio_ops *ops;
99 
100 	ops = virtio_get_ops(vdev->parent);
101 
102 	return ops->set_features(vdev->parent);
103 }
104 
105 int virtio_find_vqs(struct udevice *vdev, unsigned int nvqs,
106 		    struct virtqueue *vqs[])
107 {
108 	struct dm_virtio_ops *ops;
109 
110 	ops = virtio_get_ops(vdev->parent);
111 
112 	return ops->find_vqs(vdev->parent, nvqs, vqs);
113 }
114 
115 int virtio_del_vqs(struct udevice *vdev)
116 {
117 	struct dm_virtio_ops *ops;
118 
119 	ops = virtio_get_ops(vdev->parent);
120 
121 	return ops->del_vqs(vdev->parent);
122 }
123 
124 int virtio_notify(struct udevice *vdev, struct virtqueue *vq)
125 {
126 	struct dm_virtio_ops *ops;
127 
128 	ops = virtio_get_ops(vdev->parent);
129 
130 	return ops->notify(vdev->parent, vq);
131 }
132 
133 void virtio_add_status(struct udevice *vdev, u8 status)
134 {
135 	u8 old;
136 
137 	if (!virtio_get_status(vdev, &old))
138 		virtio_set_status(vdev, old | status);
139 }
140 
141 int virtio_finalize_features(struct udevice *vdev)
142 {
143 	struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(vdev->parent);
144 	u8 status;
145 	int ret;
146 
147 	ret = virtio_set_features(vdev);
148 	if (ret)
149 		return ret;
150 
151 	if (uc_priv->legacy)
152 		return 0;
153 
154 	virtio_add_status(vdev, VIRTIO_CONFIG_S_FEATURES_OK);
155 	ret = virtio_get_status(vdev, &status);
156 	if (ret)
157 		return ret;
158 	if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
159 		debug("(%s): device refuses features %x\n", vdev->name, status);
160 		return -ENODEV;
161 	}
162 
163 	return 0;
164 }
165 
166 void virtio_driver_features_init(struct virtio_dev_priv *priv,
167 				 const u32 *feature,
168 				 u32 feature_size,
169 				 const u32 *feature_legacy,
170 				 u32 feature_legacy_size)
171 {
172 	priv->feature_table = feature;
173 	priv->feature_table_size = feature_size;
174 	priv->feature_table_legacy = feature_legacy;
175 	priv->feature_table_size_legacy = feature_legacy_size;
176 }
177 
178 int virtio_init(void)
179 {
180 	struct udevice *bus;
181 	int ret;
182 
183 	/* Enumerate all known virtio devices */
184 	ret = uclass_first_device(UCLASS_VIRTIO, &bus);
185 	if (ret)
186 		return ret;
187 
188 	while (bus) {
189 		ret = uclass_next_device(&bus);
190 		if (ret)
191 			break;
192 	}
193 
194 	return ret;
195 }
196 
197 static int virtio_uclass_pre_probe(struct udevice *udev)
198 {
199 	struct dm_virtio_ops *ops;
200 
201 	ops = (struct dm_virtio_ops *)(udev->driver->ops);
202 
203 	/*
204 	 * Check virtio transport driver ops here so that we don't need
205 	 * check these ops each time when the virtio_xxx APIs are called.
206 	 *
207 	 * Only generation op is optional. All other ops are must-have.
208 	 */
209 	if (!ops->get_config || !ops->set_config ||
210 	    !ops->get_status || !ops->set_status ||
211 	    !ops->get_features || !ops->set_features ||
212 	    !ops->find_vqs || !ops->del_vqs ||
213 	    !ops->reset || !ops->notify)
214 		return -ENOENT;
215 
216 	return 0;
217 }
218 
219 static int virtio_uclass_post_probe(struct udevice *udev)
220 {
221 	struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(udev);
222 	char dev_name[30], *str;
223 	struct udevice *vdev;
224 	int ret;
225 
226 	if (uc_priv->device > VIRTIO_ID_MAX_NUM) {
227 		debug("(%s): virtio device ID %d exceeds maximum num\n",
228 		      udev->name, uc_priv->device);
229 		return 0;
230 	}
231 
232 	if (!virtio_drv_name[uc_priv->device]) {
233 		debug("(%s): underlying virtio device driver unavailable\n",
234 		      udev->name);
235 		return 0;
236 	}
237 
238 	snprintf(dev_name, sizeof(dev_name), "%s#%d",
239 		 virtio_drv_name[uc_priv->device], udev->seq);
240 	str = strdup(dev_name);
241 	if (!str)
242 		return -ENOMEM;
243 
244 	ret = device_bind_driver(udev, virtio_drv_name[uc_priv->device],
245 				 str, &vdev);
246 	if (ret == -ENOENT) {
247 		debug("(%s): no driver configured\n", udev->name);
248 		return 0;
249 	}
250 	if (ret) {
251 		free(str);
252 		return ret;
253 	}
254 	device_set_name_alloced(vdev);
255 
256 	INIT_LIST_HEAD(&uc_priv->vqs);
257 
258 	return 0;
259 }
260 
261 static int virtio_uclass_child_post_bind(struct udevice *vdev)
262 {
263 	/* Acknowledge that we've seen the device */
264 	virtio_add_status(vdev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
265 
266 	return 0;
267 }
268 
269 static int virtio_uclass_child_pre_probe(struct udevice *vdev)
270 {
271 	struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(vdev->parent);
272 	u64 device_features;
273 	u64 driver_features;
274 	u64 driver_features_legacy;
275 	int i;
276 	int ret;
277 
278 	/*
279 	 * Save the real virtio device (eg: virtio-net, virtio-blk) to
280 	 * the transport (parent) device's uclass priv for future use.
281 	 */
282 	uc_priv->vdev = vdev;
283 
284 	/*
285 	 * We always start by resetting the device, in case a previous driver
286 	 * messed it up. This also tests that code path a little.
287 	 */
288 	ret = virtio_reset(vdev);
289 	if (ret)
290 		goto err;
291 
292 	/* We have a driver! */
293 	virtio_add_status(vdev, VIRTIO_CONFIG_S_DRIVER);
294 
295 	/* Figure out what features the device supports */
296 	virtio_get_features(vdev, &device_features);
297 	debug("(%s) plain device features supported %016llx\n",
298 	      vdev->name, device_features);
299 	if (!(device_features & (1ULL << VIRTIO_F_VERSION_1)))
300 		uc_priv->legacy = true;
301 
302 	/* Figure out what features the driver supports */
303 	driver_features = 0;
304 	for (i = 0; i < uc_priv->feature_table_size; i++) {
305 		unsigned int f = uc_priv->feature_table[i];
306 
307 		WARN_ON(f >= 64);
308 		driver_features |= (1ULL << f);
309 	}
310 
311 	/* Some drivers have a separate feature table for virtio v1.0 */
312 	if (uc_priv->feature_table_legacy) {
313 		driver_features_legacy = 0;
314 		for (i = 0; i < uc_priv->feature_table_size_legacy; i++) {
315 			unsigned int f = uc_priv->feature_table_legacy[i];
316 
317 			WARN_ON(f >= 64);
318 			driver_features_legacy |= (1ULL << f);
319 		}
320 	} else {
321 		driver_features_legacy = driver_features;
322 	}
323 
324 	if (uc_priv->legacy) {
325 		debug("(%s): legacy virtio device\n", vdev->name);
326 		uc_priv->features = driver_features_legacy & device_features;
327 	} else {
328 		debug("(%s): v1.0 complaint virtio device\n", vdev->name);
329 		uc_priv->features = driver_features & device_features;
330 	}
331 
332 	/* Transport features always preserved to pass to finalize_features */
333 	for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
334 		if ((device_features & (1ULL << i)) &&
335 		    (i == VIRTIO_F_VERSION_1))
336 			__virtio_set_bit(vdev->parent, i);
337 
338 	debug("(%s) final negotiated features supported %016llx\n",
339 	      vdev->name, uc_priv->features);
340 	ret = virtio_finalize_features(vdev);
341 	if (ret)
342 		goto err;
343 
344 	return 0;
345 
346 err:
347 	virtio_add_status(vdev, VIRTIO_CONFIG_S_FAILED);
348 	return ret;
349 }
350 
351 static int virtio_uclass_child_post_probe(struct udevice *vdev)
352 {
353 	/* Indicates that the driver is set up and ready to drive the device */
354 	virtio_add_status(vdev, VIRTIO_CONFIG_S_DRIVER_OK);
355 
356 	return 0;
357 }
358 
359 UCLASS_DRIVER(virtio) = {
360 	.name	= "virtio",
361 	.id	= UCLASS_VIRTIO,
362 	.flags	= DM_UC_FLAG_SEQ_ALIAS,
363 	.pre_probe = virtio_uclass_pre_probe,
364 	.post_probe = virtio_uclass_post_probe,
365 	.child_post_bind = virtio_uclass_child_post_bind,
366 	.child_pre_probe = virtio_uclass_child_pre_probe,
367 	.child_post_probe = virtio_uclass_child_post_probe,
368 	.per_device_auto_alloc_size = sizeof(struct virtio_dev_priv),
369 };
370