Difference between revisions of "User:Lesterwm"
| Line 60: | Line 60: | ||
:Answers: | :Answers: | ||
#''The major device number 234 is part of a range of unassigned numbers. What is the range?'' 231-239 | #''The major device number 234 is part of a range of unassigned numbers. What is the range?'' 231-239 | ||
| − | #''What's the new line added to hello_init do?'' | + | #''What's the new line added to hello_init do?'' Registers this device driver with the given major number (234) and tells the kernel where to find the required file operation functions (open, read, write, ...) |
| − | #''What does mknod do?'' | + | #''What does mknod do?'' Creates a file in /dev/ that represents the device with the given major number (in our case, 234) |
| − | #''Once your device is running try $ cat /proc/devices. Do you see your device?'' | + | #''Once your device is running try $ cat /proc/devices. Do you see your device?'' Yes |
| − | #''Convert the example in our text to use the newer method. It's only a couple of additional lines, but you will have to read the book to know how to do it.'' | + | #''Convert the example in our text to use the newer method. It's only a couple of additional lines, but you will have to read the book to know how to do it.'' Done |
| − | #''Modify the scull_load script (call it hello_load) on page 47, of chapter 3, to load your module.'' | + | #''Modify the scull_load script (call it hello_load) on page 47, of chapter 3, to load your module.'' Done |
| − | #''Test it with use-hello.c from page 222 of Embedded Linux Primer.'' | + | #''Test it with use-hello.c from page 222 of Embedded Linux Primer.'' Done |
| − | #''Write a hello_unload script that will rmmod the driver and remove the nodes in /dev'' | + | #''Write a hello_unload script that will rmmod the driver and remove the nodes in /dev'' Done |
| − | #''Modify hello.c to pass the major device number in as a parameter during insmod.'' | + | #''Modify hello.c to pass the major device number in as a parameter during insmod.'' Done |
Optional: Stretch time, I though these would be easy, but after reading up on them, they look rather involved. | Optional: Stretch time, I though these would be easy, but after reading up on them, they look rather involved. | ||
| − | #''How can your driver find what the minor device number is?'' | + | #''How can your driver find what the minor device number is?'' When the device is opened, an inode reference is passed. There is a macro called 'iminor' which takes an inode and returns the minor number. |
| − | + | static int hello_open(struct inode *inode, struct file *file) | |
| + | { | ||
| + | /* We can change the logic of this function based on the | ||
| + | * minor number of our device */ | ||
| + | printk("hello_open: successful opened minor number %u\n", | ||
| + | iminor(inode)); | ||
| + | |||
| + | return 0; | ||
| + | } | ||
;[[ECE497 Lab09 Development Tools | Lab 09]] | ;[[ECE497 Lab09 Development Tools | Lab 09]] | ||
Revision as of 22:43, 1 May 2011
Status Report
Listings
- Chapter 4
- Not Done
- Chapter 5
- Done
- Chapter 6
- Not Done
- Chapter 7
- Not Done
- Chapter 8
- Not Done
Labs
- Lab 00
- Status: Complete
- Observations: N/A (I already had linux installed)
- Answers: N/A
- Lab 01
- Status: Complete
- Observations: Using the SPED image, you can't boot your Beagle using USB OTG for power (it throws a kernel panic). This is because the kernel image included on image does not have the necessary USB gadget module built-in (its a dynamic module).
- Answers: N/A
- Lab 02
- Status: Complete
- Observations: Build.tar.gz is absolutely huge. Is all of that necessary? I find myself building the kernel outside of the OE tree because it is just too complicated otherwise. This is a great lab and one that I kept coming back to, its extremely important to the course
- Answers: N/A
- Lab 03
- Status: Incomplete
- Observations:
- Answers:
- Lab 04
- Status: Done
- Observations: This lab is incomplete, but following its spirit, I configured the kernel to my liking. I had to reconfigure from the default Angstrom configuration when I wanted to get networking and power over USB working, since the USB OTG gadget had to be compiled into the kernel (it can't by a dynamic module). I used gconfig to configure it.
- Answers: N/A
- Lab 05
- Status: Complete
- Observations: I completed this short lab as part of Lab 08. In that lab I added an Example character device module to the necessary Kconfig file.
- Answers: N/A
- Lab 06
- Status: Complete
- Observations: I've spent a lot of time on this subject while trying to get static MAC addresses working. I wrote up a wiki article based on what I learned. See ECE497 Modifying Kernel Command Line Parameters.
- Answers: N/A
- Lab 07
- Status: Not Started
- Observations:
- Answers:
- Lab 08
- Status: Complete
- Observations: This is definitely my favorite lab. Very well constructed, challenging but not impossible.
- Answers:
- The major device number 234 is part of a range of unassigned numbers. What is the range? 231-239
- What's the new line added to hello_init do? Registers this device driver with the given major number (234) and tells the kernel where to find the required file operation functions (open, read, write, ...)
- What does mknod do? Creates a file in /dev/ that represents the device with the given major number (in our case, 234)
- Once your device is running try $ cat /proc/devices. Do you see your device? Yes
- Convert the example in our text to use the newer method. It's only a couple of additional lines, but you will have to read the book to know how to do it. Done
- Modify the scull_load script (call it hello_load) on page 47, of chapter 3, to load your module. Done
- Test it with use-hello.c from page 222 of Embedded Linux Primer. Done
- Write a hello_unload script that will rmmod the driver and remove the nodes in /dev Done
- Modify hello.c to pass the major device number in as a parameter during insmod. Done
Optional: Stretch time, I though these would be easy, but after reading up on them, they look rather involved.
- How can your driver find what the minor device number is? When the device is opened, an inode reference is passed. There is a macro called 'iminor' which takes an inode and returns the minor number.
static int hello_open(struct inode *inode, struct file *file)
{
/* We can change the logic of this function based on the
* minor number of our device */
printk("hello_open: successful opened minor number %u\n",
iminor(inode));
return 0;
}
- Lab 09
- Status:
- Observations:
- Answers:
- Lab 10
- Status:
- Observations:
- Answers:
- Lab 11
- Status:
- Observations:
- Answers:
- Lab 12
- Status:
- Observations:
- Answers:
- Lab 13
- Status:
- Observations:
- Answers:
ECE497 Pages
These are pages that I have created in order to help the current and next class of ECE497 - Embedded 32-bit Linux
