User space application access to Hardware. HPS FPGA bridge

[Altera_Forum]

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 custom_software.zip). 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.  http://www.alteraforum.com/forum/attachment.php?attachmentid=12403&stc=1   I must have done something wrong, any ideas ? Thanks in advance  Mathieu

[Altera_Forum]

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

[Altera_Forum]

Hi 

 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 : https://lists.rocketboards.org/pipermail/rfi/2015-august/003260.html  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  Regards

[Altera_Forum]

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 https://lists.rocketboards.org/piper...st/003260.html  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)  Regards Mathieu