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User Image QT Creator for kernel driver development Nov. 10, 2016, 11:12 a.m.

Autocomplete (For Qmake)

QMAKE_CXXFLAGS = -I/usr/src/linux-3.1.8-1-ARCH/include
QMAKE_CFLAGS = -I/usr/src/linux-3.1.8-1-ARCH/include


 

 

 

User Image Kernel Options And System Debugging Nov. 9, 2016, 2:43 p.m.

Debug Options For Kernel:


- Kernel hacking 
-- [*] Show timing information on printks 
-- [*] Magic SysRq key 
-- [*] Debug filesystem
-- [*] Kernel debugging 
-- [*] Detect Soft Lockups 
-- [ ] Collect scheduler statistics 
-- [*] Debug slab memory allocations 
-- [*] Memory leak debugging 
-- [*] RT Mutex debugging, deadlock detection 
-- [*] Spinlock debugging 
-- [*] Sleep-inside-spinlock checking 
-- [ ] kobject debugging 
-- [ ] Highmem debugging 
-- [ ] Compile the kernel with debug info

Mount debugfs

mount -t debugfs none /sys/kernel/debug

 

Test GPIO

echo 30 > /sys/class/gpio/export
echo in > /sys/class/gpio/gpio30/direction
cat /sys/class/gpio/gpio30/value
cat /sys/kernel/debug/gpio

 

Disable Peripherals

http://labs.isee.biz/index.php/Mux_instructions

Set sdmmc2_dat5 to gpio137 (mode 4):

# -> root@localhost:/sys/kernel/debug/omap_mux# 
cat sdmmc2_dat5
# Result
# name: sdmmc2_dat5.gpio_137 (0x48002166/0x136 = 0x0004), b ah3, t NA
# mode: OMAP_PIN_OUTPUT | OMAP_MUX_MODE4
# signals: sdmmc2_dat5 | sdmmc2_dir_dat1 | cam_global_reset | sdmmc3_dat1 | gpio_137 | hsusb3_tll_stp | mm3_rxdp | safe_mode

# Set sdmmc2_dat5 to gpio137 (mode 4): 
echo 0x004 > sdmmc2_dat5 

# Check that gpio137 is in user space: 

# -> root@localhost:/sys/class/gpio# 
ls
# Result: export  gpio137  gpio138  gpio139  gpio170  gpio64  gpiochip0  gpiochip128  gpiochip160  gpiochip192  gpiochip32  gpiochip64  gpiochip96  unexport

 

List iomem and ioports

 

cat /proc/iomem
cat /proc/ioports

 

User Image Python Ve Enduro Üzerine June 27, 2016, 9:54 p.m.

Yazılım bir sanattır. Motosiklet kullanmak da öyle. İkiside incelik ister. Altında bastırdıkları amortisörleri, susturucusuz egzosları ve kaskı kafası yerine koluna takanlardan bahsetmediğim gibi diploma almayı yeterlilik sayan, incelik nezaket ve yaratıcılıktan yoksun, yazılım geliştirmeyi esnaflıkla eşdeğer bir kazanç kapısı gören meslektaşlarımdan da bahsetmiyorum. Etrafındaki insanlara kod yazıyorum hek yapıyorum diye "hava atan"  yeniyetmeler de bu yazının ilgi alanına girmiyor. Bohemian Rhapsody'nin içindeki pattern'i ve yaratıcılığı görebilen insanlardan bahsediyorum.

Peki neden yazılım ve motosiklet değil de python ve enduro?

Aslında konunun altında yatan toplumun çizdiği iki düz çizginin arasında gitmektense çizgilerin dışında ilerleyen insanlar. Yaratıcılıklarının farkında olanlar. Python nasıl open source dünyasının bir markası ise kullandığım motosiklet olan Honda-CRF'de enduro dünyasının bir markası. İkisi de ilk başlandığında aksaklıklarla başlar. İkiside bildiğiniz kalıpların dışındadır çünkü. 

İlk enduro makinamla araziden inip piste girdiğimizde rampada takla atıp düştükten sonra 1 ay boyunca sağ tarafıma yatarken kemiğim ağrımıştı. Ama o 1 günlük haz 1 ay boyunca mutlu uyuyabilemmi ve tekrar piste gideceğim günü hayal etmemi sağladı. Son düşüşüm oldu. Ne yapmam gerektiğini artık biliyordum.

Pythonla ilk kod yazdığım zamanlarda loop döngülerindeki zaman kaybı yüzüme tokat gibi çarpmıştı.  Ama loop'un içini map ettikten, bir kaç optimizasyondan  ve pypy ile çalıştırdıktan sonra ARM bir makinada C'ye yakın bir performans elde edince aldığım haz tarif edilemezdi.

Artık biliyordum. Ne hayabusa ne de R1 beni arazide takip edemezlerdi.

Artık biliyordum ne C# ne de senelerce ekmeğini yediğim Java artık beni takip edemezlerdi.

CRF ile artık trafiğin içinde sıkışmış değildim. Önümde yepyeni bir dünya vardı bu sıkış trafikte. Kaldırımlar ve merdivenler :)

Python ile yazılım dünyasının doktrinleri arasında sıkışmış değildim. Her ne kadar python nesne yönelimli bir dil olarak bilinsede esasen alakası yoktur, nesne tabanlı bir dildir ve bu da yazmak istediğiniz tipe göre biçim değiştirmenize olanak sağlar. Bu da yaratıcılığıma kimsenin gem vuramıyacağı anlamına geliyordu :)

Arazide düştükten sonra ben bir ayda kendime gelebilirken , motorumun yamulan gidonunun ve ayak peginin bir klavuz ve mengene yardımıyla 10 dk da düzeltildiğini ve orjinali gibi olduğunu gördüğümde anladım ki herhangi bir sorunda beni yarıyolda bırakmıyacaktı ve düzeltmem dakikalarımı alacaktı.

Django ile sıfırdan ilk blogumu oluşturduğumda(bu oluyor kendileri) eşim köklü bir değişiklik istediğinde bana sadece yarım saat zamana mal olduğunu gördüğümde anladım ki beni yarıyolda bırakmıyacaktı ve düzeltmem dakikalarımı alacaktı.

Arkadaşımın R1'i ile otobanda kalıp, servisin gıkını çıkarmayıp, taşımacıya bir ton para ödeyip kendi parasıyla rezil olmasını izlerken, bir başka arkadaşım dağda kaldığında enduro kullananların bir kurtarma ekibi oluşturduğunu gördüğümde kullandığım motosikletin değerini bir kez daha anladım.

Çalıştığım iş yerleri C# ve benzeri dillerde destek almak için bir ton para ödeyip paralarıyla rezil olurken; sıkıştığımda irc üzerinden insanların yardımcı olmak için bana can attıklarını gördüğümde açık kaynak kod paylaşımcılığının değerini bir kez daha anladım.

Sözün özü Python dünyası da enduro dünyası da paylaşım ve özgürlük üzerine kuruludur. Ama hayatları boyunca ne paylaşmayı ne de gerçek anlamda özgürlüğü tatmamış olanlara anlatması zor oluyor maalesef :)

User Image V4L June 24, 2016, 12:05 p.m.
# aktif olan çözünürlük
v4l2-ctl -V

# Seçili format
v4l2-ctl --list-formats

# Tümü
v4l2-ctl --list-formats-ext

########################################

lsusb
# >> Bus 001 Device 032: ID 046d:089d Logitech, Inc. QuickCam E2500 series

lsusb -s 001:032 -v | egrep "Width|Height"
#>>    wWidth    640
#>>    wHeight   480
#>>    wWidth    1280
#>>    wHeight   1024

 

User Image GPIO June 16, 2016, 4:37 p.m.

echo 169 > /sys/class/gpio/export
# echo "in" > /sys/class/gpio/gpio169/direction
echo "out" > /sys/class/gpio/gpio169/direction
echo 0 > /sys/class/gpio/gpio169/value
echo 1 > /sys/class/gpio/gpio169/value
echo 169 > /sys/class/gpio/unexport

# if Kernel configuration ---> Kernel hacking ---> Debug FS enabled
# You can check who uses which gpio

mount -t debugfs none /sys/kernel/debug
cat /sys/kernel/debug/gpio

# pincontrol
# /sys/kernel/debug/pinctrl/

 

User Image RAR June 15, 2016, 3:53 p.m.
rar a -R -m5 -v10m myarchive.rar compress_directory

a= add

r= recursive

m= compression ratio (1-5)

User Image Pypy Vs Python April 1, 2016, 5:05 p.m.

Results:

Arm - Beagleboard

 

Calculation Table (in seconds) Python PyPy
 Array Copy 89.420 19.510 
Float Arithmetic 77.180 0.640
Integer Arithmetic 75.720 6.270
String Search 14.860 0.640
Total 257.210 27.070

 


 

80x86 64bit (4 core but single thread)

Calculation Table (in seconds) Python PyPy
 Array Copy 26.906 8.053 
Float Arithmetic 25.386 0.178
Integer Arithmetic 23.494 1.988
String Search 4.856 0.219
Total 80.642 10.438

 

 

 

 

 

 

 

 

 

 

 

 


 

Test Code:

# -*- coding: utf-8 -*-
import time

__author__ = 'ozgur'
__creation_date__ = '4/1/16' '4:11 PM'

TEST_STRING = '''The hierarchy shown above is relative to a PREFIX directory. PREFIX is computed by starting from the directory where the executable resides, and “walking up” the filesystem until we find a directory containing lib_pypy and lib-python/2.7.
The archives (.tar.bz2 or .zip) containing PyPy releases already contain the correct hierarchy, so to run PyPy it’s enough to unpack the archive, and run the bin/pypy executable.
To install PyPy system wide on unix-like systems, it is recommended to put the whole hierarchy alone (e.g. in /opt/pypy2.1) and put a symlink to the pypy executable into /usr/bin or /usr/local/bin
If the executable fails to find suitable libraries, it will report debug: WARNING: library path not found, using compiled-in sys.path and then attempt to continue normally. If the default path is usable, most code will be fine. However, the sys.prefix will be unset and some existing libraries assume beni bul that this is never the case.'''


class StressSuite():
    def __init__(self):
        pass

    @staticmethod
    def test_array():
        a = []
        for y in range(1000000):
            txt_arr = "deneme".split()
            for item in txt_arr:
                a.append(item)
        del (a)

    @staticmethod
    def test_float():
        a = 0.5612342
        b = 653.324556
        c = a + b
        d = a * b
        e = b / a
        f = a - b

    @staticmethod
    def test_int():
        a = 5612342
        b = 653324556
        c = a + b
        d = a * b
        e = b / a
        f = a - b

    @staticmethod
    def test_string():
        b = TEST_STRING.find("beni bul")

    def runtest(self, label, loop, func_exec):
        print "Testing : ", label
        s_time = time.time()
        for x in range(loop):
            func_exec()
        print "%s exec time : %.3f sn." % (label, (time.time() - s_time))

    def run(self):
        s_time = time.time()
        self.runtest("Array Copy", 100, StressSuite.test_array)
        self.runtest("Float Arithmetic", 100000000, StressSuite.test_float)
        self.runtest("Integer Arithmetic", 100000000, StressSuite.test_int)
        self.runtest("String Search", 10000000, StressSuite.test_string)
        print "Total exec time : %.3f sn." % (time.time() - s_time)


if __name__ == '__main__':
    ss = StressSuite()
    ss.run()

 

 

User Image Simple Linux Device Driver March 31, 2016, 4:39 p.m.

 

This driver :

1) Creates a character device called kbdozgur

2) Handles an interrupt(keyboard) , buffers it

-  send buffered data when kbdozgur opened for read

- prints into dmesg when you put a message in kbdozgur

 


 

#include <linux/init.h>           // Macros used to mark up functions e.g. __init __exit
#include <linux/module.h>         // Core header for loading LKMs into the kernel
#include <linux/device.h>         // Header to support the kernel Driver Model
#include <linux/kernel.h>         // Contains types, macros, functions for the kernel
#include <linux/fs.h>             // Header for the Linux file system support
#include <asm/uaccess.h>          // Required for the copy to user function
#include <linux/interrupt.h>
#include <asm/io.h>

#define  DEVICE_NAME "kbdozgur"   ///< The device will appear at /dev/kbdozgur using this value
#define  CLASS_NAME  "kbdozgur"   ///< The device class -- this is a character device driver
MODULE_AUTHOR("Mehmet Ozgur Bayhan");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Kill all the white men!");
MODULE_VERSION("0.2");

#define BUFFER_SIZE 200
static unsigned char messageFromInterrupt[BUFFER_SIZE]; //buffer that holds interrupt values
static short bufferCounter = 0; //buffer counter for loop

static int majorNumber; ///< Stores the device number -- determined automatically
static char messageFromUser[BUFFER_SIZE] = { 0 }; ///< Memory for the string that is passed from userspace
//static short size_of_message; ///< Used to remember the size of the string stored
static int numberOpens = 0; ///< Counts the number of times the device is opened
static struct class* kbdozgurcharClass = NULL; ///< The device-driver class struct pointer
static struct device* kbdozgurcharDevice = NULL; ///< The device-driver device struct pointer

// The prototype functions for the character driver -- must come before the struct definition
static int dev_open(struct inode *, struct file *);
static int dev_release(struct inode *, struct file *);
static ssize_t dev_read(struct file *, char *, size_t, loff_t *);
static ssize_t dev_write(struct file *, const char *, size_t, loff_t *);

static struct file_operations fops = { .open = dev_open, .read = dev_read, .write = dev_write, .release = dev_release, };

irq_handler_t irq_handler(int irq, void *dev_id, struct pt_regs *regs) {
	static unsigned char scancode;
	//Read keyboard status
	scancode = inb(0x60);

	if (scancode == 0x01) {
		printk(KERN_INFO "MOB: Inputs are > %s\n", messageFromInterrupt);
		bufferCounter = 0;
		memset(&messageFromInterrupt[0], 0, sizeof(messageFromInterrupt));
	}
	else if (scancode == 0x1E) {
		messageFromInterrupt[bufferCounter] = 'a';
		bufferCounter++;
	}
	else if (scancode == 0x1F) {
		messageFromInterrupt[bufferCounter] = 's';
		bufferCounter++;
	}
	else if (scancode == 0x20) {
		messageFromInterrupt[bufferCounter] = 'd';
		bufferCounter++;
	}
	else if (scancode == 0x21) {
		messageFromInterrupt[bufferCounter] = 'f';
		bufferCounter++;
	}
	else if (scancode == 0x22) {
		messageFromInterrupt[bufferCounter] = 'g';
		bufferCounter++;
	}
	else if (scancode == 0x23) {
		messageFromInterrupt[bufferCounter] = 'h';
		bufferCounter++;
	}
	else if (scancode == 0x24) {
		messageFromInterrupt[bufferCounter] = 'j';
		bufferCounter++;
	}
	if (bufferCounter >= BUFFER_SIZE) {
		bufferCounter = 0;
		memset(&messageFromInterrupt[0], 0, sizeof(messageFromInterrupt));
	}

	return (irq_handler_t) IRQ_HANDLED;
}

static int init_mod(void) {
	int result;

	/*
	 *****************************
	 * Create Character device
	 *****************************
	 */

	// Try to dynamically allocate a major number for the device
	majorNumber = register_chrdev(0, DEVICE_NAME, &fops);
	if (majorNumber < 0) {
		printk(KERN_ALERT "MOB: kbdozgurcharClass failed to register a major number\n");
		return majorNumber;
	}
	printk(KERN_INFO "MOB: registered correctly with major number %d\n", majorNumber);
	// Register the device class
	kbdozgurcharClass = class_create(THIS_MODULE, CLASS_NAME);
	if (IS_ERR(kbdozgurcharClass)) { // Check for error and clean up if there is
		unregister_chrdev(majorNumber, DEVICE_NAME);
		printk(KERN_ALERT "MOB: Failed to register device class\n");
		return PTR_ERR(kbdozgurcharClass); // Correct way to return an error on a pointer
	}
	printk(KERN_INFO "MOB: device class registered correctly\n");

	// Register the device driver
	kbdozgurcharDevice = device_create(kbdozgurcharClass, NULL, MKDEV(majorNumber, 0), NULL, DEVICE_NAME);
	if (IS_ERR(kbdozgurcharDevice)) { // Clean up if there is an error
		class_destroy(kbdozgurcharClass); // Repeated code but the alternative is goto statements
		unregister_chrdev(majorNumber, DEVICE_NAME);
		printk(KERN_ALERT "MOB: Failed to create the device\n");
		return PTR_ERR(kbdozgurcharDevice);
	}
	printk(KERN_INFO "MOB: device class created correctly\n"); // Made it! device was initialized
	
	/*
	 *****************************
	 * Bind interrupt
	 *****************************
	 */

	//	Request IRQ 1, the keyboard IRQ, to go to our irq_handler SA_SHIRQ means we're willing to have othe handlers on this IRQ. SA_INTERRUPT can be used to make the handler into a fast interrupt.

	result = request_irq(1, (irq_handler_t) irq_handler, IRQF_SHARED, "kbdozgur", (void *) (irq_handler));
	if (result) printk(KERN_INFO "MOB: can't get shared interrupt for keyboard\n");

	printk(KERN_INFO "MOB: kbdozgur loaded.\n");
	return result;

}

static void exit_mod(void) {
	/*
	 * ****************************
	 * Destroy Character Device
	 * ****************************
	 */
	device_unregister(kbdozgurcharDevice);
	device_destroy(kbdozgurcharClass, MKDEV(majorNumber, 0)); // remove the device
	class_unregister(kbdozgurcharClass); // unregister the device class
	class_destroy(kbdozgurcharClass); // remove the device class
	unregister_chrdev(majorNumber, DEVICE_NAME); // unregister the major number
	printk(KERN_INFO "MOB: Goodbye from the LKM!\n");

	/*
	 * ****************************
	 * Free IRQ bind
	 * ****************************
	 */
	free_irq(1, (void *) (irq_handler));
	printk(KERN_INFO "MOB: kbdozgur unloaded.\n");
}

// Default open function for device
static int dev_open(struct inode *inodep, struct file *filep) {
	numberOpens++;
	printk(KERN_INFO "MOB: Device has been opened %d time(s)\n", numberOpens);
	return 0;
}

/** @brief This function is called whenever device is being read from user space i.e. data is
 *  being sent from the device to the user. In this case is uses the copy_to_user() function to
 *  send the buffer string to the user and captures any errors.
 *  KERNEL SPACE > USER SPACE
 *  @param filep A pointer to a file object (defined in linux/fs.h)
 *  @param buffer The pointer to the buffer to which this function writes the data
 *  @param len The length of the buffer
 *  @param offset The offset if required
 */
static ssize_t dev_read(struct file *filep, char *buffer, size_t len, loff_t *offset) {
	size_t size_requested;
	if (len >= bufferCounter) size_requested = bufferCounter;
	else size_requested = len;

	//	if (copy_to_user(buffer, messageFromInterrupt, size_requested)) {
	//		bufferCounter = bufferCounter - size_requested;
	//		memset(&messageFromInterrupt[0], 0, sizeof(messageFromInterrupt));
	//		return -EFAULT;
	//	}
	//	else return size_requested;

	copy_to_user(buffer, messageFromInterrupt, size_requested);
	bufferCounter = bufferCounter - size_requested;
	memset(&messageFromInterrupt[0], 0, sizeof(messageFromInterrupt));

	return size_requested;
}

/** @brief This function is called whenever the device is being written to from user space i.e.
 *  data is sent to the device from the user. The data is copied to the messageFromUser[] array in this
 *  LKM using the sprintf() function along with the length of the string.
 *  USER SPACE > KERNEL SPACE
 *  @param filep A pointer to a file object
 *  @param buffer The buffer to that contains the string to write to the device
 *  @param len The length of the array of data that is being passed in the const char buffer
 *  @param offset The offset if required
 */
static ssize_t dev_write(struct file *filep, const char *buffer, size_t len, loff_t *offset) {
	short size_of_message;
	copy_from_user(messageFromUser, buffer, len);
	size_of_message = strlen(messageFromUser); // store the length of the stored message
	printk(KERN_INFO "MOB: Received %d characters from the user >> %s", len, messageFromUser);
	return len;
}

/** @brief The device release function that is called whenever the device is closed/released by
 *  the userspace program
 *  @param inodep A pointer to an inode object (defined in linux/fs.h)
 *  @param filep A pointer to a file object (defined in linux/fs.h)
 */
static int dev_release(struct inode *inodep, struct file *filep) {
	printk(KERN_INFO "MOB: Device successfully closed\n");
	return 0;
}
module_init(init_mod);
module_exit(exit_mod);

 

 

User Image Python - Kabuk&Uygulama Çağrıları Feb. 8, 2016, 8:58 a.m.

Here's a summary of the ways to call external programs and the advantages and disadvantages of each:

  1. os.system("some_command with args") passes the command and arguments to your system's shell. This is nice because you can actually run multiple commands at once in this manner and set up pipes and input/output redirection. For example,
    os.system("some_command < input_file | another_command > output_file")
    However, while this is convenient, you have to manually handle the escaping of shell characters such as spaces, etc. On the other hand, this also lets you run commands which are simply shell commands and not actually external programs.
    see documentation

  2. stream = os.popen("some_command with args") will do the same thing as os.systemexcept that it gives you a file-like object that you can use to access standard input/output for that process. There are 3 other variants of popen that all handle the i/o slightly differently. If you pass everything as a string, then your command is passed to the shell; if you pass them as a list then you don't need to worry about escaping anything.
    see documentation

  3. The Popen class of the subprocess module. This is intended as a replacement for os.popen but has the downside of being slightly more complicated by virtue of being so comprehensive. For example, you'd say

    print subprocess.Popen("echo Hello World", shell=True, stdout=subprocess.PIPE).stdout.read()

    instead of

    print os.popen("echo Hello World").read()

    but it is nice to have all of the options there in one unified class instead of 4 different popen functions.
    see documentation

  4. The call function from the subprocess module. This is basically just like the Popen class and takes all of the same arguments, but it simply waits until the command completes and gives you the return code. For example:

    return_code = subprocess.call("echo Hello World", shell=True)  

    see documentation

  5. If you're on Python 3.5 or later, you can use the new subprocess.run function, which is a lot like the above but even more flexible and returns a CompletedProcess object when the command finishes executing.

  6. The os module also has all of the fork/exec/spawn functions that you'd have in a C program, but I don't recommend using them directly.

The subprocess module should probably be what you use.

Finally please be aware that for all methods where you pass the final command to be executed by the shell as a string and you are responsible for escaping it there are serious security implications if any part of the string that you pass can not be fully trusted (for example if a user is entering some/any part of the string). If unsure only use these methods with constants. To give you a hint of the implications consider this code

print subprocess.Popen("echo %s " % user_input, stdout=PIPE).stdout.read()

and imagine that the user enters "my mama didnt love me && rm -rf /".


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