AXI GPIO Interrupt

Hi Kevin,

thank you for your answer. Interrupts works now but i have a problem with printf() in a while loop. In the function wait_for_interrupt() is a breakpoint. If i push a button, read() unblocks the programm and wait at the breakpoint but printf() doesn't work. If i try this without a while loop, it works. With a for loop, i can push a button i times and after that, the printf() output follows i times. DO you have an idea for that?

regards,
Sebastian


For each other, here is my hardware, the device tree and the code for a axi gpio interrupt.
It's important to load your drivers at the kernel manual with the shell command:
modprobe uio_pdrv_genirq.of_id="generic-uio"
Furthermore it's important to configure and enable the interrupts at your code. After an interrupt, the interrupts have to reenable.

Hardware:
http://up.picr.de/22058574ln.jpg

Devicetree:
chosen {
        bootargs = "console=ttyPS0,115200 earlyprintk uio_pdrv_genirq.of_id=generic-uio";
     };
};

&axi_gpio_0 {
t compatible = "generic-uio";
t reg = <0x41200000 0x10000>;
tinterrupt-parent = <&intc>;
tinterrupts = <0 29 4>;
};

Code:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mman.h>
#include <fcntl.h>

#define GPIO_MAP_SIZE tt0x10000
#define GPIO_DATA_OFFSETt0x00
#define GPIO_TRI_OFFSETtt0x04
#define GPIO_DATA2_OFFSETt0x08
#define GPIO_TRI2_OFFSETt0x0C
#define GPIO_GLOBAL_IRQtt0x11C
#define GPIO_IRQ_CONTROLt0x128
#define GPIO_IRQ_STATUStt0x120


inline void gpio_write(void *gpio_base, unsigned int offset, unsigned int value)
{
t*((volatile unsigned *)(gpio_base + offset)) = value;
}

inline unsigned int gpio_read(void *gpio_base, unsigned int offset)
{
treturn *((volatile unsigned *)(gpio_base + offset));
}

unsigned int get_memory_size(char *sysfs_path_file)
{
tFILE *size_fp;
tunsigned int size;

t// open the file that describes the memory range size that is based on the
t// reg property of the node in the device tree

tsize_fp = fopen(sysfs_path_file, "r");

tif (!size_fp) {
ttprintf("unable to open the uio size file
");
ttexit(-1);
t}

t// get the size which is an ASCII string such as 0xXXXXXXXX and then be stop
t// using the file

tfscanf(size_fp, "0x%08X", &size);
tfclose(size_fp);

treturn size;
}

void wait_for_interrupt(int fd, void *gpio_ptr)
{
tint pending = 0;
tint reenable = 1;
tunsigned int reg;

t// block on the file waiting for an interrupt */
tread(fd, (void *)&pending, sizeof(int));
t////Breakoint/////
tprintf("Interrupt!");

t// the interrupt occurred for the 1st GPIO channel so clear it
treg = gpio_read(gpio_ptr, GPIO_IRQ_STATUS);
tif (reg)
ttgpio_write(gpio_ptr, GPIO_IRQ_STATUS, 1); //


t// re-enable the interrupt in the interrupt controller thru the
t// the UIO subsystem now that it's been handled

twrite(fd, (void *)&reenable, sizeof(int));

}

int main()
{
tint uio0_fd;
tvoid *ptr;
tint gpio_size;
tint reenable = 1;


tif ((uio0_fd = open("/dev/uio0", O_RDWR)) < 0)
t{
ttperror("open uio0");
t}
telse{printf("uio0 opened
");}

tgpio_size = get_memory_size("/sys/class/uio/uio0/maps/map0/size");

tptr = mmap(NULL, gpio_size, PROT_READ|PROT_WRITE, MAP_SHARED, uio0_fd, 0);

tif (ptr == MAP_FAILED) {
tttprintf("Mmap call failure.
");
tttreturn -1;
tt}
tgpio_write(ptr, GPIO_TRI_OFFSET, 0xFF); // GPIO Channel 1 input

tgpio_write(ptr, GPIO_GLOBAL_IRQ, 0x80000000); // GIER, 31. Bit
tgpio_write(ptr, GPIO_IRQ_CONTROL, 1);  // Channel 1 Interrupt enable

twrite(uio0_fd, (void *)&reenable, sizeof(int)); // 2nd start

t//wait for interrupt
twhile(1)
t{
ttwait_for_interrupt(uio0_fd, ptr);
t}


tmunmap(ptr, gpio_size);

treturn 0;
}

Hi Kevin,

thank you for your answer. Interrupts works now but i have a problem with printf() in a while loop. In the function wait_for_interrupt() is a breakpoint. If i push a button, read() unblocks the programm and wait at the breakpoint but printf() doesn't work. If i try this without a while loop, it works. With a for loop, i can push a button i times and after that, the printf() output follows i times. DO you have an idea for that?

regards,
Sebastian


For each other, here is my hardware, the device tree and the code for a axi gpio interrupt.
It's important to load your drivers at the kernel manual with the shell command:
modprobe uio_pdrv_genirq.of_id="generic-uio"
Furthermore it's important to configure and enable the interrupts at your code. After an interrupt, the interrupts have to reenable.

Hardware:
http://up.picr.de/22058574ln.jpg

Devicetree:
chosen {
        bootargs = "console=ttyPS0,115200 earlyprintk uio_pdrv_genirq.of_id=generic-uio";
     };
};

&axi_gpio_0 {
t compatible = "generic-uio";
t reg = <0x41200000 0x10000>;
tinterrupt-parent = <&intc>;
tinterrupts = <0 29 4>;
};

Code:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mman.h>
#include <fcntl.h>

#define GPIO_MAP_SIZE tt0x10000
#define GPIO_DATA_OFFSETt0x00
#define GPIO_TRI_OFFSETtt0x04
#define GPIO_DATA2_OFFSETt0x08
#define GPIO_TRI2_OFFSETt0x0C
#define GPIO_GLOBAL_IRQtt0x11C
#define GPIO_IRQ_CONTROLt0x128
#define GPIO_IRQ_STATUStt0x120


inline void gpio_write(void *gpio_base, unsigned int offset, unsigned int value)
{
t*((volatile unsigned *)(gpio_base + offset)) = value;
}

inline unsigned int gpio_read(void *gpio_base, unsigned int offset)
{
treturn *((volatile unsigned *)(gpio_base + offset));
}

unsigned int get_memory_size(char *sysfs_path_file)
{
tFILE *size_fp;
tunsigned int size;

t// open the file that describes the memory range size that is based on the
t// reg property of the node in the device tree

tsize_fp = fopen(sysfs_path_file, "r");

tif (!size_fp) {
ttprintf("unable to open the uio size file
");
ttexit(-1);
t}

t// get the size which is an ASCII string such as 0xXXXXXXXX and then be stop
t// using the file

tfscanf(size_fp, "0x%08X", &size);
tfclose(size_fp);

treturn size;
}

void wait_for_interrupt(int fd, void *gpio_ptr)
{
tint pending = 0;
tint reenable = 1;
tunsigned int reg;

t// block on the file waiting for an interrupt */
tread(fd, (void *)&pending, sizeof(int));
t////Breakoint/////
tprintf("Interrupt!");

t// the interrupt occurred for the 1st GPIO channel so clear it
treg = gpio_read(gpio_ptr, GPIO_IRQ_STATUS);
tif (reg)
ttgpio_write(gpio_ptr, GPIO_IRQ_STATUS, 1); //


t// re-enable the interrupt in the interrupt controller thru the
t// the UIO subsystem now that it's been handled

twrite(fd, (void *)&reenable, sizeof(int));

}

int main()
{
tint uio0_fd;
tvoid *ptr;
tint gpio_size;
tint reenable = 1;


tif ((uio0_fd = open("/dev/uio0", O_RDWR)) < 0)
t{
ttperror("open uio0");
t}
telse{printf("uio0 opened
");}

tgpio_size = get_memory_size("/sys/class/uio/uio0/maps/map0/size");

tptr = mmap(NULL, gpio_size, PROT_READ|PROT_WRITE, MAP_SHARED, uio0_fd, 0);

tif (ptr == MAP_FAILED) {
tttprintf("Mmap call failure.
");
tttreturn -1;
tt}
tgpio_write(ptr, GPIO_TRI_OFFSET, 0xFF); // GPIO Channel 1 input

tgpio_write(ptr, GPIO_GLOBAL_IRQ, 0x80000000); // GIER, 31. Bit
tgpio_write(ptr, GPIO_IRQ_CONTROL, 1);  // Channel 1 Interrupt enable

twrite(uio0_fd, (void *)&reenable, sizeof(int)); // 2nd start

t//wait for interrupt
twhile(1)
t{
ttwait_for_interrupt(uio0_fd, ptr);
t}


tmunmap(ptr, gpio_size);

treturn 0;
}