testing audio

Module/Makefile

@@ -3,7 +3,7 @@ KERNELDIR=/lib/modules/`uname -r`/build
 # This the the Makefile for the device driver (not your demonstration program)
 
 #Change the base name here to your module file name - no extension
-BASENAME=helloworld
+BASENAME= audio_mixer
 
 
 MODULES = $(BASENAME).ko 

Module/audio_mixer.c

@@ -0,0 +1,155 @@
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
+#include <linux/ioctl.h>
+
+#define DEVICE_NAME "audio_mixer"
+#define CLASS_NAME "audio"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Your Name");
+MODULE_DESCRIPTION("A virtual audio mixer device driver");
+MODULE_VERSION("0.1");
+
+static int major_number;
+static char *audio_channels[5] = {"Channel 1", "Channel 2", "Channel 3", "Channel 4", "Channel 5"};
+static int volumes[5] = {50, 50, 50, 50, 50};  // Volume for each channel 
+static int muted[5] = {0, 0, 0, 0, 0};  // Mute state for each channel (0: not muted, 1: muted)
+
+#define AUDIO_IOC_MAGIC 'A'
+#define AUDIO_IOC_SET_VOLUME _IOW(AUDIO_IOC_MAGIC, 0, int)
+#define AUDIO_IOC_MUTE _IOW(AUDIO_IOC_MAGIC, 1, int)
+#define AUDIO_IOC_RESET _IO(AUDIO_IOC_MAGIC, 2)
+
+static struct class *audio_class = NULL;
+static struct device *audio_device = NULL;
+
+static int device_open(struct inode *inodep, struct file *filep) {
+    printk(KERN_INFO "Audio Mixer: Device opened\n");
+    return 0;
+}
+
+static int device_release(struct inode *inodep, struct file *filep) {
+    printk(KERN_INFO "Audio Mixer: Device closed\n");
+    return 0;
+}
+
+static ssize_t device_read(struct file *filep, char *buffer, size_t len, loff_t *offset) {
+    int i;
+    char msg[256];
+    int msg_len = 0;
+
+    for (i = 0; i < 5; i++) {
+        msg_len += snprintf(msg + msg_len, sizeof(msg) - msg_len, 
+                            "%s: Volume=%d%%, Muted=%d\n", 
+                            audio_channels[i], volumes[i], muted[i]);
+    }
+
+    if (*offset >= msg_len)
+        return 0;
+
+    if (len > msg_len - *offset)
+        len = msg_len - *offset;
+
+    if (copy_to_user(buffer, msg + *offset, len)) {
+        printk(KERN_ERR "Audio Mixer: Failed to send data to user\n");
+        return -EFAULT;
+    }
+
+    *offset += len;
+    return len;
+}
+
+static ssize_t device_write(struct file *filep, const char *buffer, size_t len, loff_t *offset) {
+
+    char msg[256];
+    if (copy_from_user(msg, buffer, len)) {
+        printk(KERN_ERR "Audio Mixer: Failed to receive data from user\n");
+        return -EFAULT;
+    }
+
+    if (sscanf(msg, "CHANNEL1=%d", &volumes[0]) == 1) {
+        printk(KERN_INFO "Audio Mixer: Set Channel 1 volume to %d%%\n", volumes[0]);
+    }
+
+    return len;
+}
+
+static long device_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) {
+    int i;
+    switch (cmd) {
+        case AUDIO_IOC_SET_VOLUME:
+            if (arg >= 0 && arg <= 100) {
+                for (i = 0; i < 5; i++) {
+                    volumes[i] = arg;
+                }
+                printk(KERN_INFO "Audio Mixer: Set all channel volumes to %d%%\n", arg);
+            }
+            break;
+        case AUDIO_IOC_MUTE:
+            for (i = 0; i < 5; i++) {
+                muted[i] = 1;  // Mute all channels
+            }
+            printk(KERN_INFO "Audio Mixer: Muted all channels\n");
+            break;
+        case AUDIO_IOC_RESET:
+            for (i = 0; i < 5; i++) {
+                volumes[i] = 50;  // Reset to default volume
+                muted[i] = 0;  // Unmute all
+            }
+            printk(KERN_INFO "Audio Mixer: Reset all channels to default settings\n");
+            break;
+        default:
+            return -EINVAL;
+    }
+    return 0;
+}
+
+static struct file_operations fops = {
+    .open = device_open,
+    .release = device_release,
+    .read = device_read,
+    .write = device_write,
+    .unlocked_ioctl = device_ioctl,
+};
+
+static int __init audio_mixer_init(void) {
+    printk(KERN_INFO "Audio Mixer: Initializing the audio mixer driver\n");
+
+    major_number = register_chrdev(0, DEVICE_NAME, &fops);
+    if (major_number < 0) {
+        printk(KERN_ALERT "Audio Mixer: Failed to register a major number\n");
+        return major_number;
+    }
+
+    audio_class = class_create(THIS_MODULE, CLASS_NAME);
+    if (IS_ERR(audio_class)) {
+        unregister_chrdev(major_number, DEVICE_NAME);
+        printk(KERN_ALERT "Audio Mixer: Failed to register device class\n");
+        return PTR_ERR(audio_class);
+    }
+
+    audio_device = device_create(audio_class, NULL, MKDEV(major_number, 0), NULL, DEVICE_NAME);
+    if (IS_ERR(audio_device)) {
+        class_destroy(audio_class);
+        unregister_chrdev(major_number, DEVICE_NAME);
+        printk(KERN_ALERT "Audio Mixer: Failed to create the device\n");
+        return PTR_ERR(audio_device);
+    }
+
+    printk(KERN_INFO "Audio Mixer: Device created successfully with major number %d\n", major_number);
+    return 0;
+}
+
+static void __exit audio_mixer_exit(void) {
+    device_destroy(audio_class, MKDEV(major_number, 0));
+    class_unregister(audio_class);
+    class_destroy(audio_class);
+    unregister_chrdev(major_number, DEVICE_NAME);
+    printk(KERN_INFO "Audio Mixer: Device driver unloaded\n");
+}
+
+module_init(audio_mixer_init);
+module_exit(audio_mixer_exit);

Test/Makefile

@@ -33,8 +33,8 @@
 # will delete the executable and any object files in your directory.
 #
 
-FIRSTNAME=
-LASTNAME=
+FIRSTNAME= Michelle
+LASTNAME= Nguyen
 
 ROOTNAME=$(LASTNAME)_$(FIRSTNAME)_HW
 HW=6
@@ -61,3 +61,13 @@ run: $(ROOTNAME)$(HW)$(FOPTION)
 vrun: $(ROOTNAME)$(HW)$(FOPTION)
 	valgrind ./$(ROOTNAME)$(HW)$(FOPTION) $(RUNOPTIONS)
 
+# Additional target for audio_test
+CC = gcc
+CFLAGS = -Wall -Wextra -Werror
+
+audio_test: audio_test.c
+	$(CC) $(CFLAGS) -o audio_test audio_test.c
+
+clean:
+	rm -f audio_test
+

Test/audio_test.c

@@ -0,0 +1,42 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <errno.h>
+
+#define DEVICE_NAME "/dev/audio_mixer"
+#define AUDIO_IOC_MAGIC 'A'
+#define AUDIO_IOC_SET_VOLUME _IOW(AUDIO_IOC_MAGIC, 0, int)
+#define AUDIO_IOC_MUTE _IOW(AUDIO_IOC_MAGIC, 1, int)
+#define AUDIO_IOC_RESET _IO(AUDIO_IOC_MAGIC, 2)
+
+int main() {
+    int fd = open(DEVICE_NAME, O_RDWR);
+    if (fd < 0) {
+        perror("Failed to open the device");
+        return errno;
+    }
+
+    int volume = 75;
+    if (ioctl(fd, AUDIO_IOC_SET_VOLUME, &volume) < 0) {
+        perror("Failed to set volume");
+        close(fd);
+        return errno;
+    }
+
+    if (ioctl(fd, AUDIO_IOC_MUTE) < 0) {
+        perror("Failed to mute channels");
+        close(fd);
+        return errno;
+    }
+
+    if (ioctl(fd, AUDIO_IOC_RESET) < 0) {
+        perror("Failed to reset channels");
+        close(fd);
+        return errno;
+    }
+
+    close(fd);
+    return 0;
+}