feat(lab02): add ex06

doc/lab-01_02.typ

@@ -234,7 +234,7 @@ The `/proc/modules` file give us more details about the state of the module. We
 |> dmesg | tail -5
 [ 3559.279143]   number: 1
 [ 3581.198562] Linux module skeleton unloaded
-[ 3583.616662] Linux module skeleton ex02 loaded
+[ 3583.616662] Linux module skeleton ex03 loaded
 [ 3583.621085]   text: The answer to the Ultimate Question of Life, The Universe, and Everything
 [ 3583.621085]   number: 42
 |> modprobe -r mymodule
@@ -297,6 +297,23 @@ This number matches with this table (#link("https://www.kernel.org/doc/html/late
   ]
 )
 
+To allocate memory in the kernel, we can use the `kcalloc` function. It allows to allocate directly the memory for all element. It's also possible to use `kzalloc` in a loop to allocate memory for each element. We prefer allocate all the memory at once to avoid fragmentation and to be sure all the memory can be allocated.
+
+```bash
+struct element* element_ptr = kcalloc(elements, sizeof(struct element), GFP_KERNEL);
+
+for (int i = 0; i < elements; i++) {
+  struct element* e = element_ptr + i;
+      if (e != 0) {
+          strncpy(e->text, text, TEXT_LENGTH_MAX - 1);
+          e->unique_number = i;
+          list_add_tail(&e->node, &list_unique_elements);
+    pr_info ("add element %d: %s\n", e->unique_number, e->text);
+      }
+  }
+```
+
+#pagebreak()
 //-------------------
 // Exercise 5: Display the processor chip ID, CPU temperature and the MAC adress of the Ethernet controller
 //-------------------
@@ -315,14 +332,29 @@ This number matches with this table (#link("https://www.kernel.org/doc/html/late
       "temperature" = -1991 dot "register value" / 10 + 223000
     $
 
-    The chip ID can be verified in ```/proc/iomem```.
+    The chip ID can be verified in ```/proc/iomem```. 
-
+    The register value of the temperature can be verified in the file: ```/sys/class/thermal/thermal_zone0/temp```. 
-    The register value of the temperature can be verified in the file: ```/sys/class/thermal/thermal_zone0/temp```.
-
     The MAC address can be verified with ``` ifconfig```.
   ]
 )
 
+The resources are savec in a struct: 
+```c
+static struct resource* resources[3] = {[0] = 0,};
+```
+resources[0] is reserved for the chip ID, resources[1] for the temperature sensor and resources[2] for the Ethernet controller.
+
+We first allocate the resources with `request_mem_region` function. Then we can map the physical address to a virtual address with `ioremap` function. Finally, we can read the value of the registers with `ioread32` function. The request fail because we have an overlap with the EEPROM, but we can ignore this error because we can still read the registers with `ioremap` function.
+
+```c
+// Request the resource at (CHIP_ID_BASE_ADDR)
+resources[0] = request_mem_region(CHIP_ID_BASE_ADDR, 0x1000, "nanopi - chip ID");
+
+// Map the physical address (CHIP_ID_BASE_ADDR) to a virtual address (registers[0])
+registers[0] = ioremap(CHIP_ID_BASE_ADDR, 0x1000);
+```
+
+
 //-------------------
 // Exercise 6: Kernel thread
 //-------------------
@@ -337,6 +369,8 @@ This number matches with this table (#link("https://www.kernel.org/doc/html/late
   ]
 )
 
+Easy exercice, a thread in the kernet is a `struct task_struct*` that can be created with `kthread_run`
+
 //-------------------
 // Exercise 7: Sleeping
 //-------------------

src/01-skeleton/s02e02-parameters.c

@@ -0,0 +1,15 @@
+#include <linux/module.h>	// needed by all modules
+#include <linux/init.h>		// needed for macros
+#include <linux/kernel.h>	// needed for debugging
+
+#include <linux/moduleparam.h>
+
+static char* text = "dummy text";
+module_param(text, charp, 0664);
+static int elements = 1;
+module_param(elements, int, 0);
+
+void parameters_print(void) {
+    pr_debug("text: %s\n", text);
+    pr_debug("elements: %d\n", elements);
+}

src/01-skeleton/s02e04-dynamic_allocation.c

@@ -0,0 +1,58 @@
+#include <linux/module.h>	// needed by all modules
+#include <linux/init.h>		// needed for macros
+#include <linux/kernel.h>	// needed for debugging
+
+#include <linux/slab.h> // dynamic memory allocation
+#include <linux/list.h> // linked list
+#include <linux/string.h>
+
+#define TEXT_LENGTH_MAX 255
+
+struct element {
+    char text[TEXT_LENGTH_MAX];
+    int32_t unique_number;
+    struct list_head node;
+};
+
+static LIST_HEAD (list_unique_elements);
+
+void dynAlloc_init(void) {
+    pr_info("Initialize dynamic allocation and linked list\n");
+    
+    struct element* element_ptr = kcalloc(elements, sizeof(struct element), GFP_KERNEL);
+	if (element_ptr == 0) {
+		pr_err("Failed to allocate memory for %d elements\n", elements);
+		return;
+	}
+	
+	uint8_t i;
+	const uint8_t length = TEXT_LENGTH_MAX - 1;
+	for (i = 0; i < elements; i++) {
+		struct element* e = element_ptr + i;
+        if (e != 0) {
+            strncpy(e->text, text, length);
+            e->unique_number = i;
+            list_add_tail(&e->node, &list_unique_elements);
+			pr_info ("add element %d: %s\n", e->unique_number, e->text);
+        }
+    }
+
+    pr_info("Dynamic allocation and linked list initialized\n");
+}
+
+void dynAlloc_exit(void) {
+    pr_info("Free memory allocated for dynamic allocation and linked list\n");
+
+    struct element* e;
+
+    while (!list_empty(&list_unique_elements)) {
+        e = list_entry(list_unique_elements.next, struct element, node);
+        pr_info ("delete element %d: %s\n", e->unique_number, e->text);
+        list_del(&e->node);
+        if (e != 0) {
+            kfree(e);
+        }
+    }
+
+    pr_info("Memory allocated for dynamic allocation and linked list freed\n");
+}

src/01-skeleton/s02e05-io_memory_mapped.c

@@ -0,0 +1,105 @@
+#include <linux/module.h>	// needed by all modules
+#include <linux/init.h>		// needed for macros
+#include <linux/kernel.h>	// needed for debugging
+
+#include <linux/ioport.h>
+#include <linux/io.h>
+
+#define CHIP_ID_BASE_ADDR 0x01c14000
+#define TEMPERATURE_SENSOR_BASE_ADDR 0x01C25000
+#define ETHERNET_CONTROLLER_BASE_ADDR 0x01C30000
+
+static struct resource* resources[3] = {[0] = 0,};
+
+void ioMemoryMapped_init(void) {
+    pr_info("Initialize memory-mapped I/O\n");
+
+    // Declare variables
+    unsigned char* registers[3] = {[0] = 0,};
+    uint32_t chipid[4] = {[0] = 0,};
+    uint32_t temperature = 0;
+    uint32_t mac_address[2] = {[0] = 0,};
+
+    // Request memory
+    resources[0] = request_mem_region(CHIP_ID_BASE_ADDR, 0x1000, "nanopi - chip ID");
+    if (resources[0] == 0) {
+        pr_info("Failed to reserve memory region for chip ID\n");
+    }
+    
+    resources[1] = request_mem_region(TEMPERATURE_SENSOR_BASE_ADDR, 0x1000, "nanopi - temperature sensor");
+    if (resources[1] == 0) {
+        pr_info("Failed to reserve memory region for temperature sensor\n");
+    }
+    
+    resources[2] = request_mem_region(ETHERNET_CONTROLLER_BASE_ADDR, 0x1000, "nanopi - Ethernet controller");
+    if (resources[2] == 0) {
+        pr_info("Failed to reserve memory region for Ethernet controller\n");
+    }
+
+
+    // Map memory
+    registers[0] = ioremap(CHIP_ID_BASE_ADDR, 0x1000);
+    if (registers[0] == 0) {
+        pr_err("Failed to map processor registers for chip ID\n");
+        return;
+    }
+    registers[1] = ioremap(TEMPERATURE_SENSOR_BASE_ADDR, 0x1000);
+    if (registers[1] == 0) {
+        pr_err("Failed to map processor registers for temperature sensor\n");
+        return;
+    }
+    
+    registers[2] = ioremap(ETHERNET_CONTROLLER_BASE_ADDR, 0x1000);
+    if (registers[2] == 0) {
+        pr_err("Failed to map processor registers for Ethernet controller\n");
+        return;
+    }
+
+
+    // Read values - Chip ID
+    chipid[0] = ioread32(registers[0] + 0x200);
+    chipid[1] = ioread32(registers[0] + 0x204);
+    chipid[2] = ioread32(registers[0] + 0x208);
+    chipid[3] = ioread32(registers[0] + 0x20c);
+    pr_info(
+        "chipid=%08x'%08x'%08x'%08x\n",
+        chipid[0], chipid[1], chipid[2], chipid[3]
+    );
+
+    // Read values - Temperature
+    temperature = -1191 * (int32_t) ioread32(registers[1] + 0x80) / 10 + 223000;
+    pr_info(
+        "temperature=%d (register value: %d)\n",
+        temperature, ioread32(registers[1] + 0x80)
+    );
+
+    // Read values - MAC address
+    mac_address[0] = ioread32(registers[2] + 0x50);
+    mac_address[1] = ioread32(registers[2] + 0x54);
+    pr_info(
+        "mac-addr=%02x:%02x:%02x:%02x:%02x:%02x\n",
+        (mac_address[1] >> 0) & 0xff,
+        (mac_address[1] >> 8) & 0xff,
+        (mac_address[1] >> 16) & 0xff,
+        (mac_address[1] >> 24) & 0xff,
+        (mac_address[0] >> 0) & 0xff,
+        (mac_address[0] >> 8) & 0xff
+    );
+
+    // Unmap memory
+    iounmap(registers[0]);
+    iounmap(registers[1]);
+    iounmap(registers[2]);
+
+    pr_info("Memory-mapped I/O initialized\n");
+
+}
+
+void ioMemoryMapped_exit(void) {
+    pr_info("Free memory-mapped I/O\n");
+
+    // Release memory
+    if (resources[0] != 0) release_mem_region(CHIP_ID_BASE_ADDR, 0x1000);
+    if (resources[1] != 0) release_mem_region(TEMPERATURE_SENSOR_BASE_ADDR, 0x1000);
+    if (resources[2] != 0) release_mem_region(ETHERNET_CONTROLLER_BASE_ADDR, 0x1000);
+}

src/01-skeleton/s02e06-thread.c

@@ -0,0 +1,42 @@
+#include <linux/module.h>	// needed by all modules
+#include <linux/init.h>		// needed for macros
+#include <linux/kernel.h>	// needed for debugging
+
+
+#include <linux/kthread.h>
+#include <linux/delay.h>
+
+static struct task_struct* sample_thread;
+
+#define DELAY_S 5
+
+int thread_skeletonThread (void* data) {
+
+    pr_info("Thread started\n");
+
+    while (!kthread_should_stop()) {
+        pr_info("PING!\n");
+        ssleep(DELAY_S);
+    }
+
+    return 0;
+}
+
+void thread_init(void) {
+    pr_info("Initialize kernel thread\n");
+
+    sample_thread = kthread_run(thread_skeletonThread, NULL, "The Machine that goes");
+    if (IS_ERR(sample_thread)) {
+        pr_err("Failed to create kernel thread\n");
+        return;
+    }
+
+    pr_info("Kernel thread initialized\n");
+
+}
+
+void thread_exit(void) {
+    pr_info("Exiting kernel thread\n");
+    kthread_stop(sample_thread);
+    pr_info("Kernel thread exited\n");
+}

src/01-skeleton/skeleton.c

@@ -3,29 +3,65 @@
 #include <linux/init.h>		// needed for macros
 #include <linux/kernel.h>	// needed for debugging
 
-#include <linux/moduleparam.h>	// needed for module parameters
+#include "s02e02-parameters.c"
+#include "s02e04-dynamic_allocation.c"
+#include "s02e05-io_memory_mapped.c"
+#include "s02e06-thread.c"
 
-static char* text = "dummy text";
-module_param(text, charp, 0664);
-static int  number = 1;
-module_param(number, int, 0);
 
-static int __init skeleton_init(void)
+static int __init skeleton_init(void) {
-{
+    pr_info("Linux module skeleton ex05 loading...\n");
-	pr_info ("Linux module skeleton ex02 loaded\n");
+	pr_info("--------------------\n");
-	pr_debug ("  text: %s\n  number: %d\n", text, number);
+
+    // Lab02 - Exercise 2: Parameters
+    parameters_print();
+
+    pr_info("--------------------\n");
+
+    // Lab02 - Exercise 4: Dynamic memory allocation and linked list
+    dynAlloc_init();
+
+    pr_info("--------------------\n");
+
+    // Lab02 - Exercise 5: Memory-mapped I/O
+    ioMemoryMapped_init();
+
+    pr_info("--------------------\n");
+
+    // Lab02 - Exercise 6: Kernel thread
+    thread_init();
+
+    pr_info("--------------------\n");
+
+    pr_info("Linux module skeleton loaded\n");
 	return 0;
 }
 
-static void __exit skeleton_exit(void)
+static void __exit skeleton_exit(void) {
-{
+
-	pr_info ("Linux module skeleton unloaded\n");
+    
+    // Lab02 - Exercise 4: Dynamic memory allocation and linked list
+    dynAlloc_exit();
+
+    pr_info("--------------------\n");
+
+    // Lab02 - Exercise 5: Memory-mapped I/O
+    ioMemoryMapped_exit();
+
+    pr_info("--------------------\n");
+
+    // Lab02 - Exercise 6: Kernel thread
+    thread_exit();
+
+    pr_info("--------------------\n");
+
+    pr_info ("Linux module skeleton unloaded\n");
 }
 
-module_init (skeleton_init);
+module_init(skeleton_init);
-module_exit (skeleton_exit);
+module_exit(skeleton_exit);
 
-MODULE_AUTHOR ("Fastium <fastium.pro@proton.me>");
+MODULE_AUTHOR("Fastium <fastium.pro@proton.me>");
-MODULE_AUTHOR ("Klagarge <remi@heredero.ch>");
+MODULE_AUTHOR("Klagarge <remi@heredero.ch>");
-MODULE_DESCRIPTION ("Module skeleton");
+MODULE_DESCRIPTION("Module skeleton");
-MODULE_LICENSE ("GPL");
+MODULE_LICENSE("GPL");

src/01-skeleton/skeleton.conf

@@ -1 +1 @@
-options mymodule number=42 text="The answer to the Ultimate Question of Life, The Universe, and Everything"
+options mymodule elements=5 text="Some element"