Skip to content
GitLab
Explore
Sign in
Primary navigation
Search or go to…
Project
E
EmbeddedLinuxProject
Manage
Activity
Members
Labels
Plan
Issues
Issue boards
Milestones
Wiki
Code
Merge requests
Repository
Branches
Commits
Tags
Repository graph
Compare revisions
Snippets
Build
Pipelines
Jobs
Pipeline schedules
Artifacts
Deploy
Releases
Package registry
Container registry
Model registry
Operate
Environments
Terraform modules
Monitor
Incidents
Service Desk
Analyze
Value stream analytics
Contributor analytics
CI/CD analytics
Repository analytics
Model experiments
Help
Help
Support
GitLab documentation
Compare GitLab plans
GitLab community forum
Contribute to GitLab
Provide feedback
Terms and privacy
Keyboard shortcuts
?
Snippets
Groups
Projects
Show more breadcrumbs
Christoph-Anton Schwierz
EmbeddedLinuxProject
Commits
ebac3c45
Commit
ebac3c45
authored
4 months ago
by
fdai7354
Browse files
Options
Downloads
Patches
Plain Diff
Kernel Module 1.7
parent
2a443c48
Branches
Branches containing commit
No related tags found
1 merge request
!1
Kernel module
Changes
1
Show whitespace changes
Inline
Side-by-side
Showing
1 changed file
Kernel/kernel_M.c
+99
-55
99 additions, 55 deletions
Kernel/kernel_M.c
with
99 additions
and
55 deletions
Kernel/kernel_M.c
+
99
−
55
View file @
ebac3c45
#include
<linux/init.h>
#include
<linux/init.h>
#include
<linux/module.h>
#include
<linux/module.h>
#include
<linux/kernel.h>
#include
<linux/kernel.h>
#include
<linux/fs.h>
// For file_operations
#include
<linux/fs.h>
// For file_operations
#include
<linux/uaccess.h>
// For copy_from_user
#include
<linux/uaccess.h>
// For copy_from_user
#include
<linux/cdev.h>
// For cdev
#include
<linux/cdev.h>
// For cdev
#include
<linux/device.h>
// For device_create, class_create
#include
<linux/device.h>
// For device_create, class_create
#include
<linux/slab.h>
// For kmalloc, kfree
#include
<linux/slab.h>
// For kmalloc, kfree
#include
<linux/crc32.h>
// Include CRC32
#include
<linux/crc32.h>
// Include CRC32
#include
<linux/gpio.h>
// GPIO support
#include
<linux/delay.h>
// Delay functions
#include
<linux/jiffies.h>
// Time measurement
#include
<linux/kthread.h>
// Kernel threads
#include
<linux/sched.h>
// Task scheduling
#define DEVICE_NAME "packet_receiver"
#define DEVICE_NAME "packet_receiver"
#define CLASS_NAME "packet_class"
#define CLASS_NAME "packet_class"
#define GPIO_DATA 17 // GPIO for data transmission
#define GPIO_CLOCK 27 // GPIO for clock control
MODULE_LICENSE
(
"GPL"
);
MODULE_LICENSE
(
"GPL"
);
MODULE_AUTHOR
(
"Me :)"
);
MODULE_AUTHOR
(
"Me :)"
);
MODULE_DESCRIPTION
(
"A kernel module to receive packets from userspace."
);
MODULE_DESCRIPTION
(
"A kernel module to receive packets from userspace."
);
MODULE_VERSION
(
"1.0"
);
MODULE_VERSION
(
"1.7"
);
/*
// Structure to hold our packet data
struct packet_data {
int sender_id;
int value_id_1;
int value_1;
int value_id_2;
int value_2;
};
*/
// The size of the receive buffer
// The size of the receive buffer
#define RECV_BUF_SIZE 512
#define RECV_BUF_SIZE 512
...
@@ -34,6 +36,15 @@ static dev_t dev_number;
...
@@ -34,6 +36,15 @@ static dev_t dev_number;
static
struct
class
*
packet_class
=
NULL
;
static
struct
class
*
packet_class
=
NULL
;
static
struct
cdev
packet_cdev
;
static
struct
cdev
packet_cdev
;
// Store last valid data packet
static
char
last_valid_packet
[
256
]
=
{
0
};
// Time of last transmission
static
struct
task_struct
*
transmit_thread
;
// Flag to control loop in the thread
static
int
keep_sending
=
0
;
// This buffer will temporarily store data from userspace
// This buffer will temporarily store data from userspace
static
char
*
recv_buffer
;
static
char
*
recv_buffer
;
...
@@ -42,6 +53,8 @@ static int packet_open(struct inode *inode, struct file *file); //not used
...
@@ -42,6 +53,8 @@ static int packet_open(struct inode *inode, struct file *file); //not used
static
int
packet_release
(
struct
inode
*
inode
,
struct
file
*
file
);
//not used
static
int
packet_release
(
struct
inode
*
inode
,
struct
file
*
file
);
//not used
static
ssize_t
packet_read
(
struct
file
*
filp
,
char
__user
*
buf
,
size_t
len
,
loff_t
*
offset
);
//not used
static
ssize_t
packet_read
(
struct
file
*
filp
,
char
__user
*
buf
,
size_t
len
,
loff_t
*
offset
);
//not used
static
ssize_t
packet_write
(
struct
file
*
filp
,
const
char
__user
*
buf
,
size_t
len
,
loff_t
*
offset
);
static
ssize_t
packet_write
(
struct
file
*
filp
,
const
char
__user
*
buf
,
size_t
len
,
loff_t
*
offset
);
static
unsigned
long
calculate_crc32
(
const
char
*
data
,
size_t
len
);
static
int
transmit_loop
(
void
*
data
);
// Kernel thread function
// File operations structure
// File operations structure
static
struct
file_operations
fops
=
{
static
struct
file_operations
fops
=
{
...
@@ -53,6 +66,7 @@ static struct file_operations fops = {
...
@@ -53,6 +66,7 @@ static struct file_operations fops = {
};
};
// CRC32 Calculation Function
// CRC32 Calculation Function
// uses the same polynomial as zlib’s standard CRC32
static
u32
calculate_crc32
(
const
char
*
data
,
size_t
len
)
{
static
u32
calculate_crc32
(
const
char
*
data
,
size_t
len
)
{
return
crc32
(
0
,
data
,
len
);
return
crc32
(
0
,
data
,
len
);
}
}
...
@@ -63,6 +77,36 @@ static int packet_open(struct inode *inode, struct file *file) {
...
@@ -63,6 +77,36 @@ static int packet_open(struct inode *inode, struct file *file) {
return
0
;
return
0
;
}
}
// ====================== Kernel Thread for Continuous Sending ======================
static
int
transmit_loop
(
void
*
data
)
{
while
(
!
kthread_should_stop
())
{
if
(
keep_sending
&&
strlen
(
last_valid_packet
)
>
0
)
{
// Wait for clock signal
if
(
gpio_get_value
(
GPIO_CLOCK
)
==
1
)
{
printk
(
KERN_INFO
"packet_receiver: Clock HIGH -> Pausing transmission.
\n
"
);
msleep
(
100
);
// Small sleep to avoid busy looping
continue
;
}
// Transmit the last valid packet
for
(
size_t
i
=
0
;
i
<
strlen
(
last_valid_packet
);
i
++
)
{
gpio_set_value
(
GPIO_DATA
,
1
);
msleep
(
1
);
gpio_set_value
(
GPIO_DATA
,
0
);
msleep
(
1
);
}
printk
(
KERN_INFO
"packet_receiver: Sent data to GPIO %d
\n
"
,
GPIO_DATA
);
// Wait 3x the transmission time before sending again
msleep
(
strlen
(
last_valid_packet
)
*
3
);
}
else
{
msleep
(
100
);
// Wait if no valid packet
}
}
return
0
;
}
// ====================== Device Read ======================
// ====================== Device Read ======================
static
ssize_t
packet_read
(
struct
file
*
filp
,
char
__user
*
buf
,
size_t
len
,
loff_t
*
offset
)
{
static
ssize_t
packet_read
(
struct
file
*
filp
,
char
__user
*
buf
,
size_t
len
,
loff_t
*
offset
)
{
printk
(
KERN_INFO
"packet_receiver: Read called.
\n
"
);
printk
(
KERN_INFO
"packet_receiver: Read called.
\n
"
);
...
@@ -86,61 +130,39 @@ static ssize_t packet_write(struct file *filp, const char __user *buf, size_t le
...
@@ -86,61 +130,39 @@ static ssize_t packet_write(struct file *filp, const char __user *buf, size_t le
// Ensure null-termination
// Ensure null-termination
recv_buffer
[
to_copy
]
=
'\0'
;
recv_buffer
[
to_copy
]
=
'\0'
;
/* // Placeholders for the fields:
struct packet_data p_data;
p_data.sender_id = -1;
p_data.value_id_1 = -1;
p_data.value_1 = -1;
p_data.value_id_2 = -1;
p_data.value_2 = -1;
*/
unsigned
int
sender_hex
=
0
;
unsigned
int
sender_hex
=
0
;
int
value_id_0
=
-
1
,
value_id_1
=
-
1
;
int
value_id_0
=
-
1
,
value_id_1
=
-
1
;
char
value_str_0
[
64
]
=
{
0
};
char
value_str_0
[
64
]
=
{
0
};
char
value_str_1
[
64
]
=
{
0
};
char
value_str_1
[
64
]
=
{
0
};
unsigned
long
crc_val
=
0
;
unsigned
long
crc_val
=
0
;
// Example format:
// "SENDER=1 ID1=100 VAL1=222 ID2=101 VAL2=333"
// "SENDER=10 VID1=11 VAL1=100 VID2=12 VAL2=200"
/*
sscanf(recv_buffer, "SENDER=%d VID1=%d VAL1=%d VID2=%d VAL2=%d",
&p_data.sender_id,
&p_data.value_id_1,
&p_data.value_1,
&p_data.value_id_2,
&p_data.value_2);
*/
int
matches
=
sscanf
(
recv_buffer
,
"SENDER=0x%x VALUE_ID=%d VALUE=%63s VALUE_ID=%d VALUE=%63s CRC=0x%lx"
,
&
sender_hex
,
&
value_id_0
,
value_str_0
,
&
value_id_1
,
value_str_1
,
&
crc_val
);
// Print the received packet data
/* printk(KERN_INFO "packet_receiver: Received packet -> "
"sender=0x%x, valID1=%d, val1=%d, valID2=%d, val2=%d\n",
p_data.sender_id,
p_data.value_id_1, p_data.value_1,
p_data.value_id_2, p_data.value_2);
*/
printk
(
KERN_INFO
"packet_receiver: Parsed fields [matches=%d]:
\n
"
,
matches
);
printk
(
KERN_INFO
"packet_receiver: Parsed fields [matches=%d]:
\n
"
,
matches
);
printk
(
KERN_INFO
" sender=0x%X
\n
"
,
sender_hex
);
printk
(
KERN_INFO
" sender=0x%X
\n
"
,
sender_hex
);
printk
(
KERN_INFO
" value_id_0=%d value_0=
\"
%s
\"\n
"
,
value_id_0
,
value_str_0
);
printk
(
KERN_INFO
" value_id_0=%d value_0=
\"
%s
\"\n
"
,
value_id_0
,
value_str_0
);
printk
(
KERN_INFO
" value_id_1=%d value_1=
\"
%s
\"\n
"
,
value_id_1
,
value_str_1
);
printk
(
KERN_INFO
" value_id_1=%d value_1=
\"
%s
\"\n
"
,
value_id_1
,
value_str_1
);
printk
(
KERN_INFO
" crc=0x%lX
\n
"
,
crc_val
);
printk
(
KERN_INFO
" crc=0x%lX
\n
"
,
crc_val
);
// Prepare the payload for CRC verification
char
crc_buffer
[
256
];
snprintf
(
crc_buffer
,
sizeof
(
crc_buffer
),
"SENDER=0x%x VALUE_ID=%d VALUE=%s VALUE_ID=%d VALUE=%s"
,
sender_hex
,
value_id_0
,
value_str_0
,
value_id_1
,
value_str_1
);
// Calculate CRC32 for the received data excluding the CRC field
// Calculate CRC32 for the received data excluding the CRC field
size_t
crc_len
=
strrchr
(
recv_buffer
,
'C'
)
-
recv
_buffer
;
unsigned
long
computed_crc
=
calculate_crc32
(
crc_buffer
,
strlen
(
crc
_buffer
))
;
u32
calculated_crc
=
calculate_crc32
(
recv_buffer
,
crc_len
);
printk
(
KERN_INFO
" computed_crc=0x%lX
\n
"
,
computed_crc
);
if
(
calculated_crc
==
received_crc
)
{
// Check CRC32 before transmission
printk
(
KERN_INFO
"packet_receiver: CRC check passed!
\n
"
);
if
(
computed_crc
!=
crc_val
)
{
}
else
{
printk
(
KERN_ERR
"packet_receiver: CRC32 mismatch! Data rejected.
\n
"
);
printk
(
KERN_ERR
"packet_receiver: CRC mismatch! Expected: 0x%08X, Received: 0x%08lX
\n
"
,
return
-
EIO
;
calculated_crc
,
received_crc
);
}
}
// Store the valid packet
strcpy
(
last_valid_packet
,
crc_buffer
);
keep_sending
=
1
;
printk
(
KERN_INFO
"packet_receiver: Sent data to GPIO %d
\n
"
,
GPIO_DATA
);
// Return the number of bytes written
// Return the number of bytes written
return
len
;
return
len
;
}
}
...
@@ -205,16 +227,35 @@ static int __init packet_init(void) {
...
@@ -205,16 +227,35 @@ static int __init packet_init(void) {
return
-
ENOMEM
;
return
-
ENOMEM
;
}
}
gpio_request
(
GPIO_DATA
,
"packet_data"
);
gpio_request
(
GPIO_CLOCK
,
"packet_clock"
);
gpio_direction_output
(
GPIO_DATA
,
0
);
gpio_direction_input
(
GPIO_CLOCK
);
// Clock is an input signal
// Start the transmission thread
transmit_thread
=
kthread_run
(
transmit_loop
,
NULL
,
"packet_transmitter"
);
if
(
IS_ERR
(
transmit_thread
))
{
printk
(
KERN_ERR
"packet_receiver: Failed to create transmit_thread.
\n
"
);
kfree
(
recv_buffer
);
device_destroy
(
packet_class
,
dev_number
);
class_destroy
(
packet_class
);
cdev_del
(
&
packet_cdev
);
unregister_chrdev_region
(
dev_number
,
1
);
return
PTR_ERR
(
transmit_thread
);
}
printk
(
KERN_INFO
"packet_receiver: Module loaded.
\n
"
);
printk
(
KERN_INFO
"packet_receiver: Module loaded.
\n
"
);
return
0
;
return
0
;
}
}
// ====================== Module Exit ======================
// ====================== Module Exit ======================
static
void
__exit
packet_exit
(
void
)
{
static
void
__exit
packet_exit
(
void
)
{
// Stop the transmission thread
kthread_stop
(
transmit_thread
);
// Free recv_buffer
// Free recv_buffer
if
(
recv_buffer
)
{
kfree
(
recv_buffer
);
kfree
(
recv_buffer
);
}
// Remove device node
// Remove device node
device_destroy
(
packet_class
,
dev_number
);
device_destroy
(
packet_class
,
dev_number
);
...
@@ -224,6 +265,9 @@ static void __exit packet_exit(void) {
...
@@ -224,6 +265,9 @@ static void __exit packet_exit(void) {
cdev_del
(
&
packet_cdev
);
cdev_del
(
&
packet_cdev
);
// Free device numbers
// Free device numbers
unregister_chrdev_region
(
dev_number
,
1
);
unregister_chrdev_region
(
dev_number
,
1
);
// Free GPIOs
gpio_free
(
GPIO_DATA
);
gpio_free
(
GPIO_CLOCK
);
printk
(
KERN_INFO
"packet_receiver: Module unloaded.
\n
"
);
printk
(
KERN_INFO
"packet_receiver: Module unloaded.
\n
"
);
}
}
...
...
This diff is collapsed.
Click to expand it.
Preview
0%
Loading
Try again
or
attach a new file
.
Cancel
You are about to add
0
people
to the discussion. Proceed with caution.
Finish editing this message first!
Save comment
Cancel
Please
register
or
sign in
to comment