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12435 Discussions

User space application access to Hardware. HPS FPGA bridge

Honored Contributor II

Dear all 


I am a newbie on Altera SoC architecture, so I am trying to run a simple C Userspace application on an Arria 10 SoC (attached file 

The application tries to access a gpio controller (offset adress 0x0000_1000) controller via the hps_i_bridge_lw using a mmap function. 

When running using sudo, i got the following error message : 


root@linaro-nano:~/sandbox# sudo ./FPGAHPS  

[ 1749.499651] Unhandled fault: external abort on non-linefetch (0x818) at 0x760 

[ 1749.507198] pgd = ecccc000  

[ 1749.509891] [76c30000] *pgd=6df89831, *pte=ff201743, *ppte=ff201c33  


The h2f_lw_axi_master seems to be present in the kernel and uboot devicetree. 

Also i tried to access the address 0xFF200000 (h2f_lw_axi_master) in the U-boot environment using md/mw commands and it makes U-boot to restart.  


I must have done something wrong, any ideas ? 

Thanks in advance 


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3 Replies
Honored Contributor II

did you release the bridge from reset, after programming the image to the FPGA?

Honored Contributor II



On our board, the FPGA is loaded at startup from a flash memory using Active Serial. The resets signal from fpga to hps are hps_f2h_cold_reset_req_reset_n, hps_f2h_warm_reset_req_reset_n, they start at 0 and go high after few clock cycle. 

However I haven't seen any signals named lwhps2fpga_bridge_rst_n, which I think is responsible of the lw bridge reset. 


I found some hint there : 


I have modified the command for enabling specifically the lw_hps-2-fpga bridge but i got the following errors, i think the address is still protected 

In: serial 

Out: serial 

Err: serial 

Model: SOCFPGA Arria10 Dev Kit 

Net: dwmac.ff802000 

Hit any key to stop autoboot: 0  

SOCFPGA_ARRIA10# mw.l 0xffd13500 0x1 

SOCFPGA_ARRIA10# mw.l 0xffd13504 0x1 

SOCFPGA_ARRIA10# mw.l 0xffd11004 0xffffffff 

SOCFPGA_ARRIA10# md.l 0xffd0502c 1 

ffd0502c: 0000003f ?... 

SOCFPGA_ARRIA10# mw.l 0xffd0502c 0x3d 

SOCFPGA_ARRIA10# md.l 0xffd0502c 1 

ffd0502c: 0000003d =... 

SOCFPGA_ARRIA10# md.l 0xff200000 1 

ff200000:data abort 

pc : [<ffe0ecae>] lr : [<ffe0ec8f>] 

sp : ffe3be28 ip : ff200000 fp : 00000000 

r10: ff200000 r9 : ffe2e310 r8 : ff200000 

r7 : 00000001 r6 : 00000004 r5 : 00000004 r4 : 00000001 

r3 : ffe0d255 r2 : 00000001 r1 : ffe3be3c r0 : 00000009 

Flags: nZCv IRQs on FIQs off Mode SVC_32 

Resetting CPU ... 


resetting ... 



Any hint ? 

Thanks for your help 


Honored Contributor II

Dear all 


I think I have found a begging of a workaround. 

If you encounter a similar problem like me, here is the process : 

- first of all enable also the standard HPS-2-FPGA bridge in your Qsys system 

- follow the same instruction here 


then it is possible to access the FPGA bridge from U-boot 

I am able to run a bare metal application and access the registers. 

But still not able to do a mmap in Linux userspace (of course with the administrator's rights)