93 lines
2.1 KiB
C
93 lines
2.1 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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#include <linux/errno.h>
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#include <linux/miscdevice.h> /* for misc_register, and MISC_DYNAMIC_MINOR */
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#include <linux/types.h>
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#include <linux/uaccess.h>
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#include "speakup.h"
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#include "spk_priv.h"
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static int misc_registered;
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static int dev_opened;
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static ssize_t speakup_file_write(struct file *fp, const char __user *buffer,
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size_t nbytes, loff_t *ppos)
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{
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size_t count = nbytes;
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const char __user *ptr = buffer;
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size_t bytes;
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unsigned long flags;
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u_char buf[256];
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if (!synth)
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return -ENODEV;
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while (count > 0) {
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bytes = min(count, sizeof(buf));
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if (copy_from_user(buf, ptr, bytes))
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return -EFAULT;
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count -= bytes;
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ptr += bytes;
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spin_lock_irqsave(&speakup_info.spinlock, flags);
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synth_write(buf, bytes);
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spin_unlock_irqrestore(&speakup_info.spinlock, flags);
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}
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return (ssize_t)nbytes;
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}
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static ssize_t speakup_file_read(struct file *fp, char __user *buf,
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size_t nbytes, loff_t *ppos)
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{
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return 0;
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}
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static int speakup_file_open(struct inode *ip, struct file *fp)
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{
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if (!synth)
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return -ENODEV;
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if (xchg(&dev_opened, 1))
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return -EBUSY;
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return 0;
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}
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static int speakup_file_release(struct inode *ip, struct file *fp)
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{
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dev_opened = 0;
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return 0;
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}
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static const struct file_operations synth_fops = {
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.read = speakup_file_read,
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.write = speakup_file_write,
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.open = speakup_file_open,
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.release = speakup_file_release,
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};
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static struct miscdevice synth_device = {
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.minor = MISC_DYNAMIC_MINOR,
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.name = "synth",
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.fops = &synth_fops,
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};
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void speakup_register_devsynth(void)
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{
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if (misc_registered != 0)
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return;
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/* zero it so if register fails, deregister will not ref invalid ptrs */
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if (misc_register(&synth_device)) {
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pr_warn("Couldn't initialize miscdevice /dev/synth.\n");
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} else {
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pr_info("initialized device: /dev/synth, node (MAJOR %d, MINOR %d)\n",
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MISC_MAJOR, synth_device.minor);
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misc_registered = 1;
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}
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}
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void speakup_unregister_devsynth(void)
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{
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if (!misc_registered)
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return;
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pr_info("speakup: unregistering synth device /dev/synth\n");
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misc_deregister(&synth_device);
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misc_registered = 0;
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}
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