1// SPDX-License-Identifier: GPL-2.0 OR MIT 2 3/* 4 * Xen para-virtual sound device 5 * 6 * Copyright (C) 2016-2018 EPAM Systems Inc. 7 * 8 * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> 9 */ 10 11#include <linux/delay.h> 12#include <linux/module.h> 13 14#include <xen/page.h> 15#include <xen/platform_pci.h> 16#include <xen/xen.h> 17#include <xen/xenbus.h> 18 19#include <xen/xen-front-pgdir-shbuf.h> 20#include <xen/interface/io/sndif.h> 21 22#include "xen_snd_front.h" 23#include "xen_snd_front_alsa.h" 24#include "xen_snd_front_evtchnl.h" 25 26static struct xensnd_req * 27be_stream_prepare_req(struct xen_snd_front_evtchnl *evtchnl, u8 operation) 28{ 29 struct xensnd_req *req; 30 31 req = RING_GET_REQUEST(&evtchnl->u.req.ring, 32 evtchnl->u.req.ring.req_prod_pvt); 33 req->operation = operation; 34 req->id = evtchnl->evt_next_id++; 35 evtchnl->evt_id = req->id; 36 return req; 37} 38 39static int be_stream_do_io(struct xen_snd_front_evtchnl *evtchnl) 40{ 41 if (unlikely(evtchnl->state != EVTCHNL_STATE_CONNECTED)) 42 return -EIO; 43 44 reinit_completion(&evtchnl->u.req.completion); 45 xen_snd_front_evtchnl_flush(evtchnl); 46 return 0; 47} 48 49static int be_stream_wait_io(struct xen_snd_front_evtchnl *evtchnl) 50{ 51 if (wait_for_completion_timeout(&evtchnl->u.req.completion, 52 msecs_to_jiffies(VSND_WAIT_BACK_MS)) <= 0) 53 return -ETIMEDOUT; 54 55 return evtchnl->u.req.resp_status; 56} 57 58int xen_snd_front_stream_query_hw_param(struct xen_snd_front_evtchnl *evtchnl, 59 struct xensnd_query_hw_param *hw_param_req, 60 struct xensnd_query_hw_param *hw_param_resp) 61{ 62 struct xensnd_req *req; 63 int ret; 64 65 mutex_lock(&evtchnl->u.req.req_io_lock); 66 67 mutex_lock(&evtchnl->ring_io_lock); 68 req = be_stream_prepare_req(evtchnl, XENSND_OP_HW_PARAM_QUERY); 69 req->op.hw_param = *hw_param_req; 70 mutex_unlock(&evtchnl->ring_io_lock); 71 72 ret = be_stream_do_io(evtchnl); 73 74 if (ret == 0) 75 ret = be_stream_wait_io(evtchnl); 76 77 if (ret == 0) 78 *hw_param_resp = evtchnl->u.req.resp.hw_param; 79 80 mutex_unlock(&evtchnl->u.req.req_io_lock); 81 return ret; 82} 83 84int xen_snd_front_stream_prepare(struct xen_snd_front_evtchnl *evtchnl, 85 struct xen_front_pgdir_shbuf *shbuf, 86 u8 format, unsigned int channels, 87 unsigned int rate, u32 buffer_sz, 88 u32 period_sz) 89{ 90 struct xensnd_req *req; 91 int ret; 92 93 mutex_lock(&evtchnl->u.req.req_io_lock); 94 95 mutex_lock(&evtchnl->ring_io_lock); 96 req = be_stream_prepare_req(evtchnl, XENSND_OP_OPEN); 97 req->op.open.pcm_format = format; 98 req->op.open.pcm_channels = channels; 99 req->op.open.pcm_rate = rate; 100 req->op.open.buffer_sz = buffer_sz; 101 req->op.open.period_sz = period_sz; 102 req->op.open.gref_directory = 103 xen_front_pgdir_shbuf_get_dir_start(shbuf); 104 mutex_unlock(&evtchnl->ring_io_lock); 105 106 ret = be_stream_do_io(evtchnl); 107 108 if (ret == 0) 109 ret = be_stream_wait_io(evtchnl); 110 111 mutex_unlock(&evtchnl->u.req.req_io_lock); 112 return ret; 113} 114 115int xen_snd_front_stream_close(struct xen_snd_front_evtchnl *evtchnl) 116{ 117 __always_unused struct xensnd_req *req; 118 int ret; 119 120 mutex_lock(&evtchnl->u.req.req_io_lock); 121 122 mutex_lock(&evtchnl->ring_io_lock); 123 req = be_stream_prepare_req(evtchnl, XENSND_OP_CLOSE); 124 mutex_unlock(&evtchnl->ring_io_lock); 125 126 ret = be_stream_do_io(evtchnl); 127 128 if (ret == 0) 129 ret = be_stream_wait_io(evtchnl); 130 131 mutex_unlock(&evtchnl->u.req.req_io_lock); 132 return ret; 133} 134 135int xen_snd_front_stream_write(struct xen_snd_front_evtchnl *evtchnl, 136 unsigned long pos, unsigned long count) 137{ 138 struct xensnd_req *req; 139 int ret; 140 141 mutex_lock(&evtchnl->u.req.req_io_lock); 142 143 mutex_lock(&evtchnl->ring_io_lock); 144 req = be_stream_prepare_req(evtchnl, XENSND_OP_WRITE); 145 req->op.rw.length = count; 146 req->op.rw.offset = pos; 147 mutex_unlock(&evtchnl->ring_io_lock); 148 149 ret = be_stream_do_io(evtchnl); 150 151 if (ret == 0) 152 ret = be_stream_wait_io(evtchnl); 153 154 mutex_unlock(&evtchnl->u.req.req_io_lock); 155 return ret; 156} 157 158int xen_snd_front_stream_read(struct xen_snd_front_evtchnl *evtchnl, 159 unsigned long pos, unsigned long count) 160{ 161 struct xensnd_req *req; 162 int ret; 163 164 mutex_lock(&evtchnl->u.req.req_io_lock); 165 166 mutex_lock(&evtchnl->ring_io_lock); 167 req = be_stream_prepare_req(evtchnl, XENSND_OP_READ); 168 req->op.rw.length = count; 169 req->op.rw.offset = pos; 170 mutex_unlock(&evtchnl->ring_io_lock); 171 172 ret = be_stream_do_io(evtchnl); 173 174 if (ret == 0) 175 ret = be_stream_wait_io(evtchnl); 176 177 mutex_unlock(&evtchnl->u.req.req_io_lock); 178 return ret; 179} 180 181int xen_snd_front_stream_trigger(struct xen_snd_front_evtchnl *evtchnl, 182 int type) 183{ 184 struct xensnd_req *req; 185 int ret; 186 187 mutex_lock(&evtchnl->u.req.req_io_lock); 188 189 mutex_lock(&evtchnl->ring_io_lock); 190 req = be_stream_prepare_req(evtchnl, XENSND_OP_TRIGGER); 191 req->op.trigger.type = type; 192 mutex_unlock(&evtchnl->ring_io_lock); 193 194 ret = be_stream_do_io(evtchnl); 195 196 if (ret == 0) 197 ret = be_stream_wait_io(evtchnl); 198 199 mutex_unlock(&evtchnl->u.req.req_io_lock); 200 return ret; 201} 202 203static void xen_snd_drv_fini(struct xen_snd_front_info *front_info) 204{ 205 xen_snd_front_alsa_fini(front_info); 206 xen_snd_front_evtchnl_free_all(front_info); 207} 208 209static int sndback_initwait(struct xen_snd_front_info *front_info) 210{ 211 int num_streams; 212 int ret; 213 214 ret = xen_snd_front_cfg_card(front_info, &num_streams); 215 if (ret < 0) 216 return ret; 217 218 /* create event channels for all streams and publish */ 219 ret = xen_snd_front_evtchnl_create_all(front_info, num_streams); 220 if (ret < 0) 221 return ret; 222 223 return xen_snd_front_evtchnl_publish_all(front_info); 224} 225 226static int sndback_connect(struct xen_snd_front_info *front_info) 227{ 228 return xen_snd_front_alsa_init(front_info); 229} 230 231static void sndback_disconnect(struct xen_snd_front_info *front_info) 232{ 233 xen_snd_drv_fini(front_info); 234 xenbus_switch_state(front_info->xb_dev, XenbusStateInitialising); 235} 236 237static void sndback_changed(struct xenbus_device *xb_dev, 238 enum xenbus_state backend_state) 239{ 240 struct xen_snd_front_info *front_info = dev_get_drvdata(&xb_dev->dev); 241 int ret; 242 243 dev_dbg(&xb_dev->dev, "Backend state is %s, front is %s\n", 244 xenbus_strstate(backend_state), 245 xenbus_strstate(xb_dev->state)); 246 247 switch (backend_state) { 248 case XenbusStateReconfiguring: 249 case XenbusStateReconfigured: 250 case XenbusStateInitialised: 251 break; 252 253 case XenbusStateInitialising: 254 /* Recovering after backend unexpected closure. */ 255 sndback_disconnect(front_info); 256 break; 257 258 case XenbusStateInitWait: 259 /* Recovering after backend unexpected closure. */ 260 sndback_disconnect(front_info); 261 262 ret = sndback_initwait(front_info); 263 if (ret < 0) 264 xenbus_dev_fatal(xb_dev, ret, "initializing frontend"); 265 else 266 xenbus_switch_state(xb_dev, XenbusStateInitialised); 267 break; 268 269 case XenbusStateConnected: 270 if (xb_dev->state != XenbusStateInitialised) 271 break; 272 273 ret = sndback_connect(front_info); 274 if (ret < 0) 275 xenbus_dev_fatal(xb_dev, ret, "initializing frontend"); 276 else 277 xenbus_switch_state(xb_dev, XenbusStateConnected); 278 break; 279 280 case XenbusStateClosing: 281 /* 282 * In this state backend starts freeing resources, 283 * so let it go into closed state first, so we can also 284 * remove ours. 285 */ 286 break; 287 288 case XenbusStateUnknown: 289 case XenbusStateClosed: 290 if (xb_dev->state == XenbusStateClosed) 291 break; 292 293 sndback_disconnect(front_info); 294 break; 295 } 296} 297 298static int xen_drv_probe(struct xenbus_device *xb_dev, 299 const struct xenbus_device_id *id) 300{ 301 struct xen_snd_front_info *front_info; 302 303 front_info = devm_kzalloc(&xb_dev->dev, 304 sizeof(*front_info), GFP_KERNEL); 305 if (!front_info) 306 return -ENOMEM; 307 308 front_info->xb_dev = xb_dev; 309 dev_set_drvdata(&xb_dev->dev, front_info); 310 311 return xenbus_switch_state(xb_dev, XenbusStateInitialising); 312} 313 314static void xen_drv_remove(struct xenbus_device *dev) 315{ 316 struct xen_snd_front_info *front_info = dev_get_drvdata(&dev->dev); 317 int to = 100; 318 319 xenbus_switch_state(dev, XenbusStateClosing); 320 321 /* 322 * On driver removal it is disconnected from XenBus, 323 * so no backend state change events come via .otherend_changed 324 * callback. This prevents us from exiting gracefully, e.g. 325 * signaling the backend to free event channels, waiting for its 326 * state to change to XenbusStateClosed and cleaning at our end. 327 * Normally when front driver removed backend will finally go into 328 * XenbusStateInitWait state. 329 * 330 * Workaround: read backend's state manually and wait with time-out. 331 */ 332 while ((xenbus_read_unsigned(front_info->xb_dev->otherend, "state", 333 XenbusStateUnknown) != XenbusStateInitWait) && 334 --to) 335 msleep(10); 336 337 if (!to) { 338 unsigned int state; 339 340 state = xenbus_read_unsigned(front_info->xb_dev->otherend, 341 "state", XenbusStateUnknown); 342 pr_err("Backend state is %s while removing driver\n", 343 xenbus_strstate(state)); 344 } 345 346 xen_snd_drv_fini(front_info); 347 xenbus_frontend_closed(dev); 348} 349 350static const struct xenbus_device_id xen_drv_ids[] = { 351 { XENSND_DRIVER_NAME }, 352 { "" } 353}; 354 355static struct xenbus_driver xen_driver = { 356 .ids = xen_drv_ids, 357 .probe = xen_drv_probe, 358 .remove = xen_drv_remove, 359 .otherend_changed = sndback_changed, 360 .not_essential = true, 361}; 362 363static int __init xen_drv_init(void) 364{ 365 if (!xen_domain()) 366 return -ENODEV; 367 368 if (!xen_has_pv_devices()) 369 return -ENODEV; 370 371 /* At the moment we only support case with XEN_PAGE_SIZE == PAGE_SIZE */ 372 if (XEN_PAGE_SIZE != PAGE_SIZE) { 373 pr_err(XENSND_DRIVER_NAME ": different kernel and Xen page sizes are not supported: XEN_PAGE_SIZE (%lu) != PAGE_SIZE (%lu)\n", 374 XEN_PAGE_SIZE, PAGE_SIZE); 375 return -ENODEV; 376 } 377 378 pr_info("Initialising Xen " XENSND_DRIVER_NAME " frontend driver\n"); 379 return xenbus_register_frontend(&xen_driver); 380} 381 382static void __exit xen_drv_fini(void) 383{ 384 pr_info("Unregistering Xen " XENSND_DRIVER_NAME " frontend driver\n"); 385 xenbus_unregister_driver(&xen_driver); 386} 387 388module_init(xen_drv_init); 389module_exit(xen_drv_fini); 390 391MODULE_DESCRIPTION("Xen virtual sound device frontend"); 392MODULE_LICENSE("GPL"); 393MODULE_ALIAS("xen:" XENSND_DRIVER_NAME); 394