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 rproc_vring *rvring; 78 struct virtqueue *vq; 79 void *addr; 80 int len, size; 81 82 /* we're temporarily limited to two virtqueues per rvdev */ 83 if (id >= ARRAY_SIZE(rvdev->vring)) 84 return ERR_PTR(-EINVAL); 85 86 rvring = &rvdev->vring[id]; 87 88 addr = rvring->va; 89 len = rvring->len; 90 91 /* zero vring */ 92 size = vring_size(len, rvring->align); 93 memset(addr, 0, size); 94 95 dev_dbg(rproc->dev, "vring%d: va %p qsz %d notifyid %d\n", 96 id, addr, len, rvring->notifyid); 97 98 /* 99 * Create the new vq, and tell virtio we're not interested in 100 * the 'weak' smp barriers, since we're talking with a real device. 101 */ 102 vq = vring_new_virtqueue(len, rvring->align, vdev, false, addr, 103 rproc_virtio_notify, callback, name); 104 if (!vq) { 105 dev_err(rproc->dev, "vring_new_virtqueue %s failed\n", name); 106 return ERR_PTR(-ENOMEM); 107 } 108 109 rvring->vq = vq; 110 vq->priv = rvring; 111 112 return vq; 113 } 114 115 static void rproc_virtio_del_vqs(struct virtio_device *vdev) 116 { 117 struct virtqueue *vq, *n; 118 struct rproc *rproc = vdev_to_rproc(vdev); 119 struct rproc_vring *rvring; 120 121 /* power down the remote processor before deleting vqs */ 122 rproc_shutdown(rproc); 123 124 list_for_each_entry_safe(vq, n, &vdev->vqs, list) { 125 rvring = vq->priv; 126 rvring->vq = NULL; 127 vring_del_virtqueue(vq); 128 } 129 } 130 131 static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs, 132 struct virtqueue *vqs[], 133 vq_callback_t *callbacks[], 134 const char *names[]) 135 { 136 struct rproc *rproc = vdev_to_rproc(vdev); 137 int i, ret; 138 139 for (i = 0; i < nvqs; ++i) { 140 vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i]); 141 if (IS_ERR(vqs[i])) { 142 ret = PTR_ERR(vqs[i]); 143 goto error; 144 } 145 } 146 147 /* now that the vqs are all set, boot the remote processor */ 148 ret = rproc_boot(rproc); 149 if (ret) { 150 dev_err(rproc->dev, "rproc_boot() failed %d\n", ret); 151 goto error; 152 } 153 154 return 0; 155 156 error: 157 rproc_virtio_del_vqs(vdev); 158 return ret; 159 } 160 161 /* 162 * We don't support yet real virtio status semantics. 163 * 164 * The plan is to provide this via the VDEV resource entry 165 * which is part of the firmware: this way the remote processor 166 * will be able to access the status values as set by us. 167 */ 168 static u8 rproc_virtio_get_status(struct virtio_device *vdev) 169 { 170 return 0; 171 } 172 173 static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status) 174 { 175 dev_dbg(&vdev->dev, "status: %d\n", status); 176 } 177 178 static void rproc_virtio_reset(struct virtio_device *vdev) 179 { 180 dev_dbg(&vdev->dev, "reset !\n"); 181 } 182 183 /* provide the vdev features as retrieved from the firmware */ 184 static u32 rproc_virtio_get_features(struct virtio_device *vdev) 185 { 186 struct rproc_vdev *rvdev = vdev_to_rvdev(vdev); 187 188 return rvdev->dfeatures; 189 } 190 191 static void rproc_virtio_finalize_features(struct virtio_device *vdev) 192 { 193 struct rproc_vdev *rvdev = vdev_to_rvdev(vdev); 194 195 /* Give virtio_ring a chance to accept features */ 196 vring_transport_features(vdev); 197 198 /* 199 * Remember the finalized features of our vdev, and provide it 200 * to the remote processor once it is powered on. 201 * 202 * Similarly to the status field, we don't expose yet the negotiated 203 * features to the remote processors at this point. This will be 204 * fixed as part of a small resource table overhaul and then an 205 * extension of the virtio resource entries. 206 */ 207 rvdev->gfeatures = vdev->features[0]; 208 } 209 210 static struct virtio_config_ops rproc_virtio_config_ops = { 211 .get_features = rproc_virtio_get_features, 212 .finalize_features = rproc_virtio_finalize_features, 213 .find_vqs = rproc_virtio_find_vqs, 214 .del_vqs = rproc_virtio_del_vqs, 215 .reset = rproc_virtio_reset, 216 .set_status = rproc_virtio_set_status, 217 .get_status = rproc_virtio_get_status, 218 }; 219 220 /* 221 * This function is called whenever vdev is released, and is responsible 222 * to decrement the remote processor's refcount taken when vdev was 223 * added. 224 * 225 * Never call this function directly; it will be called by the driver 226 * core when needed. 227 */ 228 static void rproc_vdev_release(struct device *dev) 229 { 230 struct virtio_device *vdev = dev_to_virtio(dev); 231 struct rproc *rproc = vdev_to_rproc(vdev); 232 233 kref_put(&rproc->refcount, rproc_release); 234 } 235 236 /** 237 * rproc_add_virtio_dev() - register an rproc-induced virtio device 238 * @rvdev: the remote vdev 239 * 240 * This function registers a virtio device. This vdev's partent is 241 * the rproc device. 242 * 243 * Returns 0 on success or an appropriate error value otherwise. 244 */ 245 int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id) 246 { 247 struct rproc *rproc = rvdev->rproc; 248 struct device *dev = rproc->dev; 249 struct virtio_device *vdev = &rvdev->vdev; 250 int ret; 251 252 vdev->id.device = id, 253 vdev->config = &rproc_virtio_config_ops, 254 vdev->dev.parent = dev; 255 vdev->dev.release = rproc_vdev_release; 256 257 /* 258 * We're indirectly making a non-temporary copy of the rproc pointer 259 * here, because drivers probed with this vdev will indirectly 260 * access the wrapping rproc. 261 * 262 * Therefore we must increment the rproc refcount here, and decrement 263 * it _only_ when the vdev is released. 264 */ 265 kref_get(&rproc->refcount); 266 267 ret = register_virtio_device(vdev); 268 if (ret) { 269 kref_put(&rproc->refcount, rproc_release); 270 dev_err(dev, "failed to register vdev: %d\n", ret); 271 goto out; 272 } 273 274 dev_info(dev, "registered %s (type %d)\n", dev_name(&vdev->dev), id); 275 276 out: 277 return ret; 278 } 279 280 /** 281 * rproc_remove_virtio_dev() - remove an rproc-induced virtio device 282 * @rvdev: the remote vdev 283 * 284 * This function unregisters an existing virtio device. 285 */ 286 void rproc_remove_virtio_dev(struct rproc_vdev *rvdev) 287 { 288 unregister_virtio_device(&rvdev->vdev); 289 } 290