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

[Michael Davidsaver via Tech-talk <tech-talk at aps.anl.gov>]

On 12/7/20 8:24 AM, Kunjir, Shriraj via Tech-talk wrote:
> 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 <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 ?

At present, only if your FPGA logic appears to Linux as a PCI device.
Adding support for platform devices (or other non-discoverable)
device should be possible, but hasn't yet been done.


> 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*
> 
> Facility for Rare Isotope Beams
> 
>  
> 
> * *
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>  
>