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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * fireworks_hwdep.c - a part of driver for Fireworks based devices4 *5 * Copyright (c) 2013-2014 Takashi Sakamoto6 */7 8/*9 * This codes have five functionalities.10 *11 * 1.get information about firewire node12 * 2.get notification about starting/stopping stream13 * 3.lock/unlock streaming14 * 4.transmit command of EFW transaction15 * 5.receive response of EFW transaction16 *17 */18 19#include "fireworks.h"20 21static long22hwdep_read_resp_buf(struct snd_efw *efw, char __user *buf, long remained,23 loff_t *offset)24{25 unsigned int length, till_end, type;26 struct snd_efw_transaction *t;27 u8 *pull_ptr;28 long count = 0;29 30 if (remained < sizeof(type) + sizeof(struct snd_efw_transaction))31 return -ENOSPC;32 33 /* data type is SNDRV_FIREWIRE_EVENT_EFW_RESPONSE */34 type = SNDRV_FIREWIRE_EVENT_EFW_RESPONSE;35 if (copy_to_user(buf, &type, sizeof(type)))36 return -EFAULT;37 count += sizeof(type);38 remained -= sizeof(type);39 buf += sizeof(type);40 41 /* write into buffer as many responses as possible */42 spin_lock_irq(&efw->lock);43 44 /*45 * When another task reaches here during this task's access to user46 * space, it picks up current position in buffer and can read the same47 * series of responses.48 */49 pull_ptr = efw->pull_ptr;50 51 while (efw->push_ptr != pull_ptr) {52 t = (struct snd_efw_transaction *)(pull_ptr);53 length = be32_to_cpu(t->length) * sizeof(__be32);54 55 /* confirm enough space for this response */56 if (remained < length)57 break;58 59 /* copy from ring buffer to user buffer */60 while (length > 0) {61 till_end = snd_efw_resp_buf_size -62 (unsigned int)(pull_ptr - efw->resp_buf);63 till_end = min_t(unsigned int, length, till_end);64 65 spin_unlock_irq(&efw->lock);66 67 if (copy_to_user(buf, pull_ptr, till_end))68 return -EFAULT;69 70 spin_lock_irq(&efw->lock);71 72 pull_ptr += till_end;73 if (pull_ptr >= efw->resp_buf + snd_efw_resp_buf_size)74 pull_ptr -= snd_efw_resp_buf_size;75 76 length -= till_end;77 buf += till_end;78 count += till_end;79 remained -= till_end;80 }81 }82 83 /*84 * All of tasks can read from the buffer nearly simultaneously, but the85 * last position for each task is different depending on the length of86 * given buffer. Here, for simplicity, a position of buffer is set by87 * the latest task. It's better for a listening application to allow one88 * thread to read from the buffer. Unless, each task can read different89 * sequence of responses depending on variation of buffer length.90 */91 efw->pull_ptr = pull_ptr;92 93 spin_unlock_irq(&efw->lock);94 95 return count;96}97 98static long99hwdep_read_locked(struct snd_efw *efw, char __user *buf, long count,100 loff_t *offset)101{102 union snd_firewire_event event = {103 .lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS,104 };105 106 spin_lock_irq(&efw->lock);107 108 event.lock_status.status = (efw->dev_lock_count > 0);109 efw->dev_lock_changed = false;110 111 spin_unlock_irq(&efw->lock);112 113 count = min_t(long, count, sizeof(event.lock_status));114 115 if (copy_to_user(buf, &event, count))116 return -EFAULT;117 118 return count;119}120 121static long122hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count,123 loff_t *offset)124{125 struct snd_efw *efw = hwdep->private_data;126 DEFINE_WAIT(wait);127 bool dev_lock_changed;128 bool queued;129 130 spin_lock_irq(&efw->lock);131 132 dev_lock_changed = efw->dev_lock_changed;133 queued = efw->push_ptr != efw->pull_ptr;134 135 while (!dev_lock_changed && !queued) {136 prepare_to_wait(&efw->hwdep_wait, &wait, TASK_INTERRUPTIBLE);137 spin_unlock_irq(&efw->lock);138 schedule();139 finish_wait(&efw->hwdep_wait, &wait);140 if (signal_pending(current))141 return -ERESTARTSYS;142 spin_lock_irq(&efw->lock);143 dev_lock_changed = efw->dev_lock_changed;144 queued = efw->push_ptr != efw->pull_ptr;145 }146 147 spin_unlock_irq(&efw->lock);148 149 if (dev_lock_changed)150 count = hwdep_read_locked(efw, buf, count, offset);151 else if (queued)152 count = hwdep_read_resp_buf(efw, buf, count, offset);153 154 return count;155}156 157static long158hwdep_write(struct snd_hwdep *hwdep, const char __user *data, long count,159 loff_t *offset)160{161 struct snd_efw *efw = hwdep->private_data;162 u32 seqnum;163 u8 *buf;164 165 if (count < sizeof(struct snd_efw_transaction) ||166 SND_EFW_RESPONSE_MAXIMUM_BYTES < count)167 return -EINVAL;168 169 buf = memdup_user(data, count);170 if (IS_ERR(buf))171 return PTR_ERR(buf);172 173 /* check seqnum is not for kernel-land */174 seqnum = be32_to_cpu(((struct snd_efw_transaction *)buf)->seqnum);175 if (seqnum > SND_EFW_TRANSACTION_USER_SEQNUM_MAX) {176 count = -EINVAL;177 goto end;178 }179 180 if (snd_efw_transaction_cmd(efw->unit, buf, count) < 0)181 count = -EIO;182end:183 kfree(buf);184 return count;185}186 187static __poll_t188hwdep_poll(struct snd_hwdep *hwdep, struct file *file, poll_table *wait)189{190 struct snd_efw *efw = hwdep->private_data;191 __poll_t events;192 193 poll_wait(file, &efw->hwdep_wait, wait);194 195 spin_lock_irq(&efw->lock);196 if (efw->dev_lock_changed || efw->pull_ptr != efw->push_ptr)197 events = EPOLLIN | EPOLLRDNORM;198 else199 events = 0;200 spin_unlock_irq(&efw->lock);201 202 return events | EPOLLOUT;203}204 205static int206hwdep_get_info(struct snd_efw *efw, void __user *arg)207{208 struct fw_device *dev = fw_parent_device(efw->unit);209 struct snd_firewire_get_info info;210 211 memset(&info, 0, sizeof(info));212 info.type = SNDRV_FIREWIRE_TYPE_FIREWORKS;213 info.card = dev->card->index;214 *(__be32 *)&info.guid[0] = cpu_to_be32(dev->config_rom[3]);215 *(__be32 *)&info.guid[4] = cpu_to_be32(dev->config_rom[4]);216 strscpy(info.device_name, dev_name(&dev->device),217 sizeof(info.device_name));218 219 if (copy_to_user(arg, &info, sizeof(info)))220 return -EFAULT;221 222 return 0;223}224 225static int226hwdep_lock(struct snd_efw *efw)227{228 int err;229 230 spin_lock_irq(&efw->lock);231 232 if (efw->dev_lock_count == 0) {233 efw->dev_lock_count = -1;234 err = 0;235 } else {236 err = -EBUSY;237 }238 239 spin_unlock_irq(&efw->lock);240 241 return err;242}243 244static int245hwdep_unlock(struct snd_efw *efw)246{247 int err;248 249 spin_lock_irq(&efw->lock);250 251 if (efw->dev_lock_count == -1) {252 efw->dev_lock_count = 0;253 err = 0;254 } else {255 err = -EBADFD;256 }257 258 spin_unlock_irq(&efw->lock);259 260 return err;261}262 263static int264hwdep_release(struct snd_hwdep *hwdep, struct file *file)265{266 struct snd_efw *efw = hwdep->private_data;267 268 spin_lock_irq(&efw->lock);269 if (efw->dev_lock_count == -1)270 efw->dev_lock_count = 0;271 spin_unlock_irq(&efw->lock);272 273 return 0;274}275 276static int277hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,278 unsigned int cmd, unsigned long arg)279{280 struct snd_efw *efw = hwdep->private_data;281 282 switch (cmd) {283 case SNDRV_FIREWIRE_IOCTL_GET_INFO:284 return hwdep_get_info(efw, (void __user *)arg);285 case SNDRV_FIREWIRE_IOCTL_LOCK:286 return hwdep_lock(efw);287 case SNDRV_FIREWIRE_IOCTL_UNLOCK:288 return hwdep_unlock(efw);289 default:290 return -ENOIOCTLCMD;291 }292}293 294#ifdef CONFIG_COMPAT295static int296hwdep_compat_ioctl(struct snd_hwdep *hwdep, struct file *file,297 unsigned int cmd, unsigned long arg)298{299 return hwdep_ioctl(hwdep, file, cmd,300 (unsigned long)compat_ptr(arg));301}302#else303#define hwdep_compat_ioctl NULL304#endif305 306int snd_efw_create_hwdep_device(struct snd_efw *efw)307{308 static const struct snd_hwdep_ops ops = {309 .read = hwdep_read,310 .write = hwdep_write,311 .release = hwdep_release,312 .poll = hwdep_poll,313 .ioctl = hwdep_ioctl,314 .ioctl_compat = hwdep_compat_ioctl,315 };316 struct snd_hwdep *hwdep;317 int err;318 319 err = snd_hwdep_new(efw->card, "Fireworks", 0, &hwdep);320 if (err < 0)321 goto end;322 strcpy(hwdep->name, "Fireworks");323 hwdep->iface = SNDRV_HWDEP_IFACE_FW_FIREWORKS;324 hwdep->ops = ops;325 hwdep->private_data = efw;326 hwdep->exclusive = true;327end:328 return err;329}330 331