1 /* 2 * Remote processor messaging transport (OMAP platform-specific bits) 3 * 4 * Copyright (C) 2011 Texas Instruments, Inc. 5 * Copyright (C) 2011 Google, Inc. 6 * 7 * Ohad Ben-Cohen <ohad@wizery.com> 8 * Brian Swetland <swetland@google.com> 9 * 10 * This software is licensed under the terms of the GNU General Public 11 * License version 2, as published by the Free Software Foundation, and 12 * may be copied, distributed, and modified under those terms. 13 * 14 * This program is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 * GNU General Public License for more details. 18 */ 19 20 #include <linux/export.h> 21 #include <linux/remoteproc.h> 22 #include <linux/virtio.h> 23 #include <linux/virtio_config.h> 24 #include <linux/virtio_ids.h> 25 #include <linux/virtio_ring.h> 26 #include <linux/err.h> 27 #include <linux/kref.h> 28 #include <linux/slab.h> 29 30 #include "remoteproc_internal.h" 31 32 /* kick the remote processor, and let it know which virtqueue to poke at */ 33 static void rproc_virtio_notify(struct virtqueue *vq) 34 { 35 struct rproc_vring *rvring = vq->priv; 36 struct rproc *rproc = rvring->rvdev->rproc; 37 int notifyid = rvring->notifyid; 38 39 dev_dbg(&rproc->dev, "kicking vq index: %d\n", notifyid); 40 41 rproc->ops->kick(rproc, notifyid); 42 } 43 44 /** 45 * rproc_vq_interrupt() - tell remoteproc that a virtqueue is interrupted 46 * @rproc: handle to the remote processor 47 * @notifyid: index of the signalled virtqueue (unique per this @rproc) 48 * 49 * This function should be called by the platform-specific rproc driver, 50 * when the remote processor signals that a specific virtqueue has pending 51 * messages available. 52 * 53 * Returns IRQ_NONE if no message was found in the @notifyid virtqueue, 54 * and otherwise returns IRQ_HANDLED. 55 */ 56 irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int notifyid) 57 { 58 struct rproc_vring *rvring; 59 60 dev_dbg(&rproc->dev, "vq index %d is interrupted\n", notifyid); 61 62 rvring = idr_find(&rproc->notifyids, notifyid); 63 if (!rvring || !rvring->vq) 64 return IRQ_NONE; 65 66 return vring_interrupt(0, rvring->vq); 67 } 68 EXPORT_SYMBOL(rproc_vq_interrupt); 69 70 static struct virtqueue *rp_find_vq(struct virtio_device *vdev, 71 unsigned id, 72 void (*callback)(struct virtqueue *vq), 73 const char *name) 74 { 75 struct rproc_vdev *rvdev = vdev_to_rvdev(vdev); 76 struct rproc *rproc = vdev_to_rproc(vdev); 77 struct device *dev = &rproc->dev; 78 struct rproc_vring *rvring; 79 struct virtqueue *vq; 80 void *addr; 81 int len, size, ret; 82 83 /* we're temporarily limited to two virtqueues per rvdev */ 84 if (id >= ARRAY_SIZE(rvdev->vring)) 85 return ERR_PTR(-EINVAL); 86 87 if (!name) 88 return NULL; 89 90 ret = rproc_alloc_vring(rvdev, id); 91 if (ret) 92 return ERR_PTR(ret); 93 94 rvring = &rvdev->vring[id]; 95 addr = rvring->va; 96 len = rvring->len; 97 98 /* zero vring */ 99 size = vring_size(len, rvring->align); 100 memset(addr, 0, size); 101 102 dev_dbg(dev, "vring%d: va %p qsz %d notifyid %d\n", 103 id, addr, len, rvring->notifyid); 104 105 /* 106 * Create the new vq, and tell virtio we're not interested in 107 * the 'weak' smp barriers, since we're talking with a real device. 108 */ 109 vq = vring_new_virtqueue(id, len, rvring->align, vdev, false, addr, 110 rproc_virtio_notify, callback, name); 111 if (!vq) { 112 dev_err(dev, "vring_new_virtqueue %s failed\n", name); 113 rproc_free_vring(rvring); 114 return ERR_PTR(-ENOMEM); 115 } 116 117 rvring->vq = vq; 118 vq->priv = rvring; 119 120 return vq; 121 } 122 123 static void __rproc_virtio_del_vqs(struct virtio_device *vdev) 124 { 125 struct virtqueue *vq, *n; 126 struct rproc_vring *rvring; 127 128 list_for_each_entry_safe(vq, n, &vdev->vqs, list) { 129 rvring = vq->priv; 130 rvring->vq = NULL; 131 vring_del_virtqueue(vq); 132 rproc_free_vring(rvring); 133 } 134 } 135 136 static void rproc_virtio_del_vqs(struct virtio_device *vdev) 137 { 138 struct rproc *rproc = vdev_to_rproc(vdev); 139 140 /* power down the remote processor before deleting vqs */ 141 rproc_shutdown(rproc); 142 143 __rproc_virtio_del_vqs(vdev); 144 } 145 146 static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs, 147 struct virtqueue *vqs[], 148 vq_callback_t *callbacks[], 149 const char *names[]) 150 { 151 struct rproc *rproc = vdev_to_rproc(vdev); 152 int i, ret; 153 154 for (i = 0; i < nvqs; ++i) { 155 vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i]); 156 if (IS_ERR(vqs[i])) { 157 ret = PTR_ERR(vqs[i]); 158 goto error; 159 } 160 } 161 162 /* now that the vqs are all set, boot the remote processor */ 163 ret = rproc_boot(rproc); 164 if (ret) { 165 dev_err(&rproc->dev, "rproc_boot() failed %d\n", ret); 166 goto error; 167 } 168 169 return 0; 170 171 error: 172 __rproc_virtio_del_vqs(vdev); 173 return ret; 174 } 175 176 /* 177 * We don't support yet real virtio status semantics. 178 * 179 * The plan is to provide this via the VDEV resource entry 180 * which is part of the firmware: this way the remote processor 181 * will be able to access the status values as set by us. 182 */ 183 static u8 rproc_virtio_get_status(struct virtio_device *vdev) 184 { 185 return 0; 186 } 187 188 static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status) 189 { 190 dev_dbg(&vdev->dev, "status: %d\n", status); 191 } 192 193 static void rproc_virtio_reset(struct virtio_device *vdev) 194 { 195 dev_dbg(&vdev->dev, "reset !\n"); 196 } 197 198 /* provide the vdev features as retrieved from the firmware */ 199 static u32 rproc_virtio_get_features(struct virtio_device *vdev) 200 { 201 struct rproc_vdev *rvdev = vdev_to_rvdev(vdev); 202 203 return rvdev->dfeatures; 204 } 205 206 static void rproc_virtio_finalize_features(struct virtio_device *vdev) 207 { 208 struct rproc_vdev *rvdev = vdev_to_rvdev(vdev); 209 210 /* Give virtio_ring a chance to accept features */ 211 vring_transport_features(vdev); 212 213 /* 214 * Remember the finalized features of our vdev, and provide it 215 * to the remote processor once it is powered on. 216 * 217 * Similarly to the status field, we don't expose yet the negotiated 218 * features to the remote processors at this point. This will be 219 * fixed as part of a small resource table overhaul and then an 220 * extension of the virtio resource entries. 221 */ 222 rvdev->gfeatures = vdev->features[0]; 223 } 224 225 static struct virtio_config_ops rproc_virtio_config_ops = { 226 .get_features = rproc_virtio_get_features, 227 .finalize_features = rproc_virtio_finalize_features, 228 .find_vqs = rproc_virtio_find_vqs, 229 .del_vqs = rproc_virtio_del_vqs, 230 .reset = rproc_virtio_reset, 231 .set_status = rproc_virtio_set_status, 232 .get_status = rproc_virtio_get_status, 233 }; 234 235 /* 236 * This function is called whenever vdev is released, and is responsible 237 * to decrement the remote processor's refcount which was taken when vdev was 238 * added. 239 * 240 * Never call this function directly; it will be called by the driver 241 * core when needed. 242 */ 243 static void rproc_vdev_release(struct device *dev) 244 { 245 struct virtio_device *vdev = dev_to_virtio(dev); 246 struct rproc_vdev *rvdev = vdev_to_rvdev(vdev); 247 struct rproc *rproc = vdev_to_rproc(vdev); 248 249 list_del(&rvdev->node); 250 kfree(rvdev); 251 252 put_device(&rproc->dev); 253 } 254 255 /** 256 * rproc_add_virtio_dev() - register an rproc-induced virtio device 257 * @rvdev: the remote vdev 258 * 259 * This function registers a virtio device. This vdev's partent is 260 * the rproc device. 261 * 262 * Returns 0 on success or an appropriate error value otherwise. 263 */ 264 int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id) 265 { 266 struct rproc *rproc = rvdev->rproc; 267 struct device *dev = &rproc->dev; 268 struct virtio_device *vdev = &rvdev->vdev; 269 int ret; 270 271 vdev->id.device = id, 272 vdev->config = &rproc_virtio_config_ops, 273 vdev->dev.parent = dev; 274 vdev->dev.release = rproc_vdev_release; 275 276 /* 277 * We're indirectly making a non-temporary copy of the rproc pointer 278 * here, because drivers probed with this vdev will indirectly 279 * access the wrapping rproc. 280 * 281 * Therefore we must increment the rproc refcount here, and decrement 282 * it _only_ when the vdev is released. 283 */ 284 get_device(&rproc->dev); 285 286 ret = register_virtio_device(vdev); 287 if (ret) { 288 put_device(&rproc->dev); 289 dev_err(dev, "failed to register vdev: %d\n", ret); 290 goto out; 291 } 292 293 dev_info(dev, "registered %s (type %d)\n", dev_name(&vdev->dev), id); 294 295 out: 296 return ret; 297 } 298 299 /** 300 * rproc_remove_virtio_dev() - remove an rproc-induced virtio device 301 * @rvdev: the remote vdev 302 * 303 * This function unregisters an existing virtio device. 304 */ 305 void rproc_remove_virtio_dev(struct rproc_vdev *rvdev) 306 { 307 unregister_virtio_device(&rvdev->vdev); 308 } 309