mirror of
https://github.com/cirosantilli/linux-kernel-module-cheat.git
synced 2026-01-13 20:12:26 +00:00
135 lines
3.6 KiB
C
135 lines
3.6 KiB
C
/*
|
|
TODO get working. Currently I don't understand the behaviour.
|
|
|
|
TODO how to ACK interrupts? How to ensure that every interrupt gets handled separately?
|
|
|
|
TODO write to registers. Currently using /dev/mem and lspci.
|
|
|
|
Handle interrupts from userland and print a message to stdout.
|
|
|
|
- Userland driver
|
|
- https://stackoverflow.com/questions/15286772/userspace-vs-kernel-space-driver
|
|
- https://01.org/linuxgraphics/gfx-docs/drm/driver-api/uio-howto.html
|
|
- https://stackoverflow.com/questions/7986260/linux-interrupt-handling-in-user-space
|
|
- https://yurovsky.github.io/2014/10/10/linux-uio-gpio-interrupt/
|
|
- https://github.com/bmartini/zynq-axis/blob/65a3a448fda1f0ea4977adfba899eb487201853d/dev/axis.c
|
|
- https://yurovsky.github.io/2014/10/10/linux-uio-gpio-interrupt/
|
|
- http://nairobi-embedded.org/uio_example.html that website has QEMU examples for everything as usual. The example has a kernel-side which creates the memory mappings and is used by the user.
|
|
|
|
Userland driver stability questions:
|
|
|
|
- https://stackoverflow.com/questions/8030758/getting-kernel-version-from-linux-kernel-module-at-runtime/45430233#45430233
|
|
- https://stackoverflow.com/questions/37098482/how-to-build-a-linux-kernel-module-so-that-it-is-compatible-with-all-kernel-rele/45429681#45429681
|
|
- https://liquidat.wordpress.com/2007/07/21/linux-kernel-2623-to-have-stable-userspace-driver-api/
|
|
*/
|
|
|
|
#if 1
|
|
|
|
/* Adapted from: https://yurovsky.github.io/2014/10/10/linux-uio-gpio-interrupt */
|
|
|
|
#define _XOPEN_SOURCE 700
|
|
#include <fcntl.h> /* open */
|
|
#include <stdint.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <sys/stat.h>
|
|
#include <sys/types.h>
|
|
#include <unistd.h> /* write */
|
|
|
|
#include <assert.h>
|
|
#include <sys/mman.h>
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
char *dev = "/dev/uio0";
|
|
if (argc > 1) {
|
|
dev = argv[1];
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
int fd = open(dev, O_RDWR);
|
|
if (fd < 0) {
|
|
perror("open");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
|
|
/* TODO not supported by this kernel module? */
|
|
/*int *addr = mmap(NULL, sysconf(_SC_PAGE_SIZE), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);*/
|
|
/*if (addr == MAP_FAILED) {*/
|
|
/*perror("mmap");*/
|
|
/*assert(0);*/
|
|
/*}*/
|
|
/**addr = 0x12345678;*/
|
|
|
|
while (1) {
|
|
uint32_t info = 1;
|
|
size_t nb = write(fd, &info, sizeof(info));
|
|
if (nb < sizeof(info)) {
|
|
perror("write");
|
|
close(fd);
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
nb = read(fd, &info, sizeof(info));
|
|
if (nb == sizeof(info)) {
|
|
printf(__FILE__ " read = %u\n", info);
|
|
}
|
|
}
|
|
}
|
|
|
|
#else
|
|
|
|
/* Ripped from the kernel docs. */
|
|
|
|
#define _XOPEN_SOURCE 700
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <sys/stat.h>
|
|
#include <sys/types.h>
|
|
#include <unistd.h>
|
|
#include <unistd.h>
|
|
|
|
int main()
|
|
{
|
|
int uiofd;
|
|
int configfd;
|
|
int err;
|
|
int i;
|
|
unsigned icount;
|
|
unsigned char command_high;
|
|
|
|
uiofd = open("/dev/uio0", O_RDONLY);
|
|
if (uiofd < 0) {
|
|
perror("uio open:");
|
|
return errno;
|
|
}
|
|
configfd = open("/sys/class/uio/uio0/device/config", O_RDWR);
|
|
if (configfd < 0) {
|
|
perror("config open:");
|
|
return errno;
|
|
}
|
|
err = pread(configfd, &command_high, 1, 5);
|
|
if (err != 1) {
|
|
perror("command config read:");
|
|
return errno;
|
|
}
|
|
command_high &= ~0x4;
|
|
for(i = 0;; ++i) {
|
|
fprintf(stderr, "Interrupts: %d\n", icount);
|
|
err = pwrite(configfd, &command_high, 1, 5);
|
|
if (err != 1) {
|
|
perror("config write:");
|
|
break;
|
|
}
|
|
err = read(uiofd, &icount, 4);
|
|
if (err != 4) {
|
|
perror("uio read:");
|
|
break;
|
|
}
|
|
|
|
}
|
|
return errno;
|
|
}
|
|
|
|
#endif
|