EPICS driver for Xilinx ZYNQ ultrascale FPGA firmware PL register read write

["Kunjir, Shriraj via Tech-talk" <tech-talk at aps.anl.gov>]

Hello,

We have a design based on Xilinx ZYNQ Ultrascale plus FPGA. We have compiled EPICS base on the PS Linux side of the FPGA by following the tips mentioned here https://epics.anl.gov/tech-talk/2016/msg00632.php. We can read/write firmware PL side registers using busybox devmem from PS Linux and we are developing an application to read/write firmware PL registers from EPICS. Essentially, we are looking to run IOC on the Linux side of the FPGA. Are there any EPICS drivers that can do this ? Can devlib2 do this ?

 

Below is C code to read and write firmware registers (if not using busybox devmem)

 

C code to read firmware registers from Linux –

 

 

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <sys/mman.h>

#include <fcntl.h>

 

void usage(char *prog)

{

                printf("usage: %s ADDR\n",prog);

                printf("\n");

                printf("ADDR may be specified as hex values\n");

}

 

 

int main(int argc, char *argv[])

{

                int fd;

                void *ptr;

                unsigned addr, page_addr, page_offset;

                unsigned page_size=sysconf(_SC_PAGESIZE);

 

                if(argc!=2) {

                                usage(argv[0]);

                                exit(-1);

                }

 

                fd=open("/dev/mem",O_RDONLY);

                if(fd<1) {

                                perror(argv[0]);

                                exit(-1);

                }

 

                addr=strtoul(argv[1],NULL,0);

                page_addr=(addr & ~(page_size-1));

                page_offset=addr-page_addr;

 

                ptr=mmap(NULL,page_size,PROT_READ,MAP_SHARED,fd,(addr & ~(page_size-1)));

                if((int)ptr==-1) {

                                perror(argv[0]);

                                exit(-1);

                }

 

                printf("0x%08x\n",*((unsigned *)(ptr+page_offset)));

                return 0;

}

 

C code to write firmware registers from Linux  -

 

 

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <sys/mman.h>

#include <fcntl.h>

 

void usage(char *prog)

{

                printf("usage: %s ADDR VAL\n",prog);

                printf("\n");

                printf("ADDR and VAL may be specified as hex values\n");

}

 

int main(int argc, char *argv[])

{

                int fd;

                void *ptr;

                unsigned val;

                unsigned addr, page_addr, page_offset;

                unsigned page_size=sysconf(_SC_PAGESIZE);

 

                fd=open("/dev/mem",O_RDWR);

                if(fd<1) {

                                perror(argv[0]);

                                exit(-1);

                }

 

                if(argc!=3) {

                                usage(argv[0]);

                                exit(-1);

                }

 

                addr=strtoul(argv[1],NULL,0);

                val=strtoul(argv[2],NULL,0);

 

                page_addr=(addr & ~(page_size-1));

                page_offset=addr-page_addr;

 

                ptr=mmap(NULL,page_size,PROT_READ|PROT_WRITE,MAP_SHARED,fd,(addr & ~(page_size-1)));

 

                if((int)ptr==-1) {

                                perror(argv[0]);

                                exit(-1);

                }

 

                *((unsigned *)(ptr+page_offset))=val;

                return 0;

}

 

 

Raj K

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