feat(lab03): add module for ex 3

src/02-driver/charachter-oriented/Makefile

@@ -2,36 +2,21 @@
 ifneq ($(KERNELRELEASE),)
 obj-m += mymodule.o		## name of the generated module
 
-ccflags-y += -Wno-declaration-after-statement -std=gnu11
 mymodule-objs := skeleton.o	## list of objects needed for that module
 
 # Part executed when called from standard make in module source directory:
 else
+include ../../buildroot_path
 include ../../kernel_settings
 PWD := $(shell pwd)
 
-INCL+=-I. -I$(KDIR)/include -I$(KDIR)/arch/arm64/boot/dts
+all:
-DTB = mydt.dtb
-DTS = $(DTB:.dtb=.dts)
-
-all: dtb boot
 	$(MAKE) -C $(KDIR) M=$(PWD) ARCH=$(CPU) CROSS_COMPILE=$(TOOLS) modules
 
-dtb: $(DTB)
-$(DTB) : $(DTS)
-	ln -s $(KDIR)/arch/arm/boot/dts arm
-	-cpp $(INCL) -E -P -x assembler-with-cpp $(DTS) | dtc -I dts -O dtb -o $(DTB) -
-	rm arm
-
-boot:
-	mkimage -T script -A arm -C none -d boot.cmd boot.ovl
-
 clean:
 	$(MAKE) -C $(KDIR) M=$(PWD) clean
-	rm -f *.dtb *.ovl
 
 install:
 	$(MAKE) -C $(KDIR) M=$(PWD) INSTALL_MOD_PATH=$(MODPATH) modules_install
 
 endif
-

src/02-driver/charachter-oriented/ex2.c

@@ -0,0 +1,133 @@
+#include <linux/fs.h>
+#include <linux/types.h>
+#include <linux/kdev_t.h>
+#include <linux/cdev.h>
+#include <linux/minmax.h>
+#include <stddef.h>
+#include <linux/uaccess.h>
+
+// linux theory: https://linux-kernel-labs.github.io/refs/heads/master/labs/device_drivers.html
+
+#define MY_MAJOR       42
+#define MY_MAX_MINORS  5
+
+#define BUFFER_SIZE 300
+
+
+struct my_device_data {
+    struct cdev cdev;
+    /* my data starts here */
+    char buffer[BUFFER_SIZE];
+};
+
+struct my_device_data devs;
+
+// inode: https://www.kernel.org/doc/html/latest/filesystems/ext4/inodes.html
+// file: https://docs.kernel.org/filesystems/api-summary.html#c.file
+
+int skeleton_open(struct inode* i, struct file* f) {
+
+    pr_info("Open file\n");
+
+    // Get the stuct of my data
+    struct my_device_data *my_data = container_of(i->i_cdev, struct my_device_data, cdev);
+
+    // point private data on driver data, here this is a char buffer
+    f->private_data = my_data;
+
+    return 0;
+}
+
+int skeleton_release(struct inode* i, struct file* f) {
+
+    pr_info("Release file\n");
+
+    return 0;
+}
+
+ssize_t skeleton_read(struct file* f, char* __user buf, size_t count, loff_t* off) {
+
+    pr_info("Read file\n");
+
+    struct my_device_data *my_data = (struct my_device_data *) f->private_data;
+    ssize_t len = min(BUFFER_SIZE - ((size_t)*off), count);
+
+    if (len <= 0) {
+        pr_info("Cannot read data for length: %ld\n", len);
+        return 0;
+    }
+
+
+    /* read data from my_data->buffer to user buffer */
+    if (copy_to_user(buf, my_data->buffer + *off, len)) {
+        pr_info("Failed to copy to user space buffer\n");
+        return -EFAULT;
+    }
+
+    *off += len;
+    return len;
+
+}
+
+ssize_t skeleton_write(struct file* f, const char* __user buf, size_t count, loff_t* off) {
+
+    pr_info("Write file\n");
+
+    struct my_device_data *my_data = (struct my_device_data *) f->private_data;
+    ssize_t len = min(BUFFER_SIZE - ((size_t)*off), count);
+
+    if (len <= 0) {
+        pr_info("Cannot write data for length: %ld\n", len);
+        return 0;
+    }
+
+
+    /* read data from user buffer to my_data->buffer */
+    if (copy_from_user(my_data->buffer + *off, buf, len)) {
+        pr_info("Failed to copy from user space buffer\n");
+        return -EFAULT;
+    }
+
+
+    *off += len;
+    return len;
+}
+
+
+static struct file_operations skeleton_fops = {
+    .owner   = THIS_MODULE,
+    .open    = skeleton_open,
+    .read    = skeleton_read,
+    .write   = skeleton_write,
+    .release = skeleton_release,
+};
+
+
+int ex2_init(void) {
+    pr_info("Load exercice 2\n");
+    int ret = register_chrdev_region(MKDEV(MY_MAJOR, 0), MY_MAX_MINORS, "My module");
+
+    if (ret != 0) {
+        /* report error */
+        pr_info("Module registration error: %d\n", ret);
+        return ret;
+    }
+
+    /* initialize devs fields */
+    cdev_init(&devs.cdev, &skeleton_fops);
+    ret = cdev_add(&devs.cdev, MKDEV(MY_MAJOR, 0), 1);
+
+    if (ret != 0) {
+        /* report error */
+        pr_info("cdev add error: %d\n", ret);
+        return ret;
+    }
+
+    return ret;
+}
+
+void ex2_exit(void) {
+
+    cdev_del(&devs.cdev);
+    unregister_chrdev_region(MKDEV(MY_MAJOR, 0), MY_MAX_MINORS);
+}

src/02-driver/charachter-oriented/skeleton.c

@@ -0,0 +1,38 @@
+#include <linux/module.h>  // needed by all modules
+#include <linux/init.h>    // needed for macros
+#include <linux/kernel.h>  // needed for debugging
+
+#include "ex2.c"
+
+
+static int __init skeleton_init(void) {
+    int ret = 0;
+
+    pr_info("My module loading...\n");
+    pr_info("----------------------\n");
+
+    ret = ex2_init();
+
+    pr_info("----------------------\n");
+    pr_info("My module is loaded\n");
+
+    return ret;
+}
+
+static void __exit skeleton_exit(void) {
+    pr_info("My module unloading...\n");
+    pr_info("----------------------\n");
+
+    ex2_exit();
+
+    pr_info("----------------------\n");
+    pr_info("My module is unloaded\n");
+}
+
+module_init (skeleton_init);
+module_exit (skeleton_exit);
+
+MODULE_AUTHOR("Fastium <fastium.pro@proton.me>");
+MODULE_AUTHOR("Klagarge <remi@heredero.ch>");
+MODULE_DESCRIPTION ("Module pilot charachter oriented");
+MODULE_LICENSE ("GPL");

src/02-driver/dts/skeleton.c

@@ -1,135 +0,0 @@
-/* skeleton.c */
-#include <linux/init.h>   /* needed for macros */
-#include <linux/kernel.h> /* needed for debugging */
-#include <linux/module.h> /* needed by all modules */
-
-#include <linux/cdev.h>    /* needed for char device driver */
-#include <linux/fs.h>      /* needed for device drivers */
-#include <linux/uaccess.h> /* needed to copy data to/from user */
-
-#include <linux/device.h> /* needed for sysfs handling */
-#include <linux/miscdevice.h>
-#include <linux/of.h>
-#include <linux/platform_device.h> /* needed for sysfs handling */
-
-static int skeleton_open(struct inode* i, struct file* f)
-{
-    pr_info("skeleton : open operation... major:%d, minor:%d\n",
-            imajor(i),
-            iminor(i));
-    return 0;
-}
-
-static int skeleton_release(struct inode* i, struct file* f)
-{
-    pr_info("skeleton: release operation...\n");
-    return 0;
-}
-
-static ssize_t skeleton_read(struct file* f,
-                             char __user* buf,
-                             size_t count,
-                             loff_t* off)
-{
-    pr_info("skeleton: read operation... read=%ld\n", count);
-    return 0;
-}
-
-static ssize_t skeleton_write(struct file* f,
-                              const char __user* buf,
-                              size_t count,
-                              loff_t* off)
-{
-    pr_info("skeleton: write operation... written=%ld\n", count);
-    return count;
-}
-
-static struct file_operations fops = {
-    .owner   = THIS_MODULE,
-    .open    = skeleton_open,
-    .read    = skeleton_read,
-    .write   = skeleton_write,
-    .release = skeleton_release,
-};
-
-struct miscdevice misc_device = {
-    .minor = MISC_DYNAMIC_MINOR,
-    .fops  = &fops,
-    .name  = "mydevice",
-    .mode  = 0777,
-};
-
-int skeleton_probe(struct platform_device* pdev)
-{
-    pr_info("skeleton - driver probe %llx (%s)- M.m=%d.%d\n",
-            (unsigned long long)pdev,
-            pdev->name,
-            MAJOR(pdev->dev.devt),
-            MINOR(pdev->dev.devt));
-
-    // register misc device ...
-    int ret = misc_register(&misc_device);
-
-    // read device tree attribute
-    struct device_node* dt_node = pdev->dev.of_node;
-    const char* prop            = 0;
-    if (dt_node)
-        ret = of_property_read_string(dt_node, "attribute", &prop);
-    else
-        pr_info("mymodule not found!\n");
-    if ((prop != 0) && (ret == 0))
-        pr_info("attribute=%s (ret=%d)\n", prop, ret);
-
-    return 0;
-}
-int skeleton_remove(struct platform_device* pdev)
-{
-    pr_info("skeleton - sysfs driver remove %llx\n", (unsigned long long)pdev);
-    misc_deregister(&misc_device);
-    return 0;
-}
-void skeleton_shutdown(struct platform_device* pdev)
-{
-    pr_info("skeleton - sysfs driver shutdown %s\n", pdev->name);
-}
-
-struct of_device_id of_skeleton[] = {
-    {
-        .compatible = "mydevice",
-    },
-    {},
-};
-MODULE_DEVICE_TABLE(of, of_skeleton);
-
-static struct platform_driver sysfs_driver = {
-    .probe    = skeleton_probe,
-    .remove   = skeleton_remove,
-    .shutdown = skeleton_shutdown,
-    .driver =
-        {
-            .name           = "mydriver",
-            .of_match_table = of_match_ptr(of_skeleton),
-        },
-};
-
-static int __init skeleton_init(void)
-{
-    pr_info("Linux module skeleton loading...\n");
-    int status = platform_driver_register(&sysfs_driver);
-    pr_info("Linux module skeleton loaded\n");
-    return status;
-}
-
-static void __exit skeleton_exit(void)
-{
-    pr_info("Linux module skeleton exiting...\n");
-    platform_driver_unregister(&sysfs_driver);
-    pr_info("Linux module skeleton unloaded\n");
-}
-
-module_init(skeleton_init);
-module_exit(skeleton_exit);
-
-MODULE_AUTHOR("Daniel Gachet <daniel.gachet@hefr.ch>");
-MODULE_DESCRIPTION("Module skeleton");
-MODULE_LICENSE("GPL");