AM5728: DSP/RTOS -ARM/Linux shared memory issue

Hi, Janardan,

Could you check if ti-mctd daemon is running on Linux side? If it is, see if it makes difference after disabling it. Also, try devmem2 to dump ocmc area to see if the data being correct.

Rex

Hi Rex,

I have tried the multiple iterations and unable to fix it. I have attached my resource table, configuration file along with this post.

Also please find the user space code used from Linux end.

Is there any thing to do in Linux DTS to accomplish this?

I tried using devmem2 and it appears like DSP/write and ARM/Read is not seeing the same memory.

Please help me fixing this issue.

Thanks,

Janardan M

6646.Documents.zip

Hi Rex,

I am doing cache write back operation after the write from DSP end, from ARM I am not doing ivalidate and as of my understanding that is not required from ARM end, correct me if I am wrong.

I have listed down the  processes running on linux, please let me know if any of the process is causing issue.

  PID USER       VSZ STAT COMMAND
    1 root      1384 S    init [5]
    2 root         0 SW   [kthreadd]
    3 root         0 SW   [ksoftirqd/0]
    4 root         0 SW   [kworker/0:0]
    5 root         0 SW<  [kworker/0:0H]
    7 root         0 SW   [rcu_preempt]
    8 root         0 SW   [rcu_sched]
    9 root         0 SW   [rcu_bh]
   10 root         0 SW   [migration/0]
   11 root         0 SW   [migration/1]
   12 root         0 SW   [ksoftirqd/1]
   14 root         0 SW<  [kworker/1:0H]
   15 root         0 SW<  [khelper]
   16 root         0 SW   [kdevtmpfs]
   17 root         0 SW<  [netns]
   18 root         0 SW<  [perf]
   20 root         0 SW<  [writeback]
   21 root         0 SW<  [crypto]
   22 root         0 SW<  [bioset]
   23 root         0 SW<  [kblockd]
   24 root         0 SW   [irq/330-4807000]
   25 root         0 SW   [irq/36-palmas]
   27 root         0 SW   [irq/331-4806000]
   28 root         0 SW   [irq/332-4807c00]
   29 root         0 SW<  [rpciod]
   30 root         0 SW   [kswapd0]
   31 root         0 SW   [fsnotify_mark]
   32 root         0 SW<  [nfsiod]
   48 root         0 SW   [irq/379-OMAP HD]
   49 root         0 SW   [kworker/u4:1]
   54 root         0 SW   [irq/27-talert]
   55 root         0 SW   [irq/228-4809c00]
   56 root         0 SW   [mmcqd/0]
   78 root         0 SW   [irq/361-4846800]
   79 root         0 SW   [irq/360-4846800]
   80 root         0 SW   [mmcqd/1]
   81 root         0 SW   [mmcqd/1boot0]
   82 root         0 SW   [mmcqd/1boot1]
   83 root         0 SW<  [deferwq]
   85 root         0 SW<  [kworker/1:1H]
   86 root         0 SW   [jbd2/mmcblk0p2-]
   87 root         0 SW<  [ext4-rsv-conver]
   88 root         0 SW   [kworker/1:2]
   89 root         0 SW<  [kworker/0:1H]
   90 root         0 SW   [kworker/0:2]
   96 root         0 SW   [irq/447-4802000]
  121 root      3232 S    /lib/udev/udevd -d
  266 root         0 SW   [kworker/0:3]
  311 root         0 SW<  [ata_sff]
  360 root         0 SW   [irq/448-mcp7941]
  366 root         0 SW   [irq/449-2-006f]
  377 root         0 SW<  [pvr_timer]
  401 root         0 SW   [irq/259-extcon_]
  402 root         0 SW   [irq/258-palmas_]
  474 root         0 SW   [kworker/u4:3]
  497 root         0 SW   [irq/73-pixcir_t]
  507 root         0 SW   [scsi_eh_0]
  508 root         0 SW<  [scsi_tmf_0]
  748 root         0 SW   [kjournald]
  797 root         0 SW<  [cryptodev_queue]
  815 root      1368 S    /usr/sbin/rngd
  942 root      1988 S    udhcpc -R -b -p /var/run/udhcpc.eth0.pid -i eth0
  949 messageb  2616 S    /usr/bin/dbus-daemon --system
  956 root      1236 S    /usr/bin/uim -f /sys/./devices/platform/kim
  959 root         0 SW<  [pvr_workqueue]
  964 root      2320 S    {runWeston} /bin/bash /usr/bin/runWeston
  971 root     24856 S    weston --idle-time=0
  974 root      3228 S    /lib/udev/udevd -d
  975 root      3228 S    /lib/udev/udevd -d
  976 root         0 SW<  [ipv6_addrconf]
  977 root      2256 S    /usr/sbin/dropbear -r /etc/dropbear/dropbear_rsa_hos
  980 root      1988 S    /usr/sbin/telnetd
  983 root      7400 S    /usr/lib/weston/weston-keyboard
  984 root      9840 S    /usr/bin/lad_dra7xx -g -l lad.txt
  989 root      8436 S    /usr/lib/weston/weston-desktop-shell
  990 rpc       2220 S    /usr/sbin/rpcbind
  995 rpcuser   1988 S    /usr/sbin/rpc.statd
 1002 root      1988 S    /sbin/syslogd -n -O /var/log/messages
 1004 root         0 SW   [kworker/1:3]
 1006 root      1988 S    /sbin/klogd -n
 1009 nobody    2476 S    /usr/sbin/thttpd -d /srv/www -p 8080
 1015 avahi     3392 S    avahi-daemon: running [am57xx-evm.local]
 1016 avahi     3392 S    avahi-daemon: chroot helper
 1027 root      4572 S    /usr/sbin/ofonod
 1036 root      5192 S    /usr/sbin/lighttpd -f /etc/lighttpd.conf
 1063 root      179m S    /usr/bin/matrix_browser http://localhost:80/
 1206 root      3400 S    /bin/login --
 1207 root      1992 S    /sbin/getty 38400 tty1
 1210 root         0 SW   [kworker/0:1]
 1211 root         0 SW   [kworker/1:0]
 1212 root      2736 S    -sh
 1213 root      2404 R    ps

I tried to access the DDR - SDRAM memory at address 0x81000000, below attached is the memory locations as seen from CCS memory window after writes are done from DSP, it appears to be proper.

I tried to read this data back from A15 using devmem2. Results are as below.

root@am57xx-evm:~# devmem2 0x81000000
/dev/mem opened.
Memory mapped at address 0xb6f4a000.
Read at address  0x81000000 (0xb6f4a000): 0x00000000
root@am57xx-evm:~# devmem2 0x81000004
/dev/mem opened.
Memory mapped at address 0xb6f9b000.
Read at address  0x81000004 (0xb6f9b004): 0x00000000
root@am57xx-evm:~# devmem2 0x81000008
/dev/mem opened.
Memory mapped at address 0xb6f7b000.
Read at address  0x81000008 (0xb6f7b008): 0x00000000
root@am57xx-evm:~# devmem2 0x8100000C
/dev/mem opened.
Memory mapped at address 0xb6fb5000.
Read at address  0x8100000C (0xb6fb500c): 0x00000000
root@am57xx-evm:~# devmem2 0x81000010
/dev/mem opened.
Memory mapped at address 0xb6f0c000.
Read at address  0x81000010 (0xb6f0c010): 0x00000000
root@am57xx-evm:~# devmem2 0x8100023C
/dev/mem opened.
Memory mapped at address 0xb6f9a000.
Read at address  0x8100023C (0xb6f9a23c): 0x00000000
root@am57xx-evm:~# devmem2 0x8100035C
/dev/mem opened.
Memory mapped at address 0xb6fbb000.
Read at address  0x8100035C (0xb6fbb35c): 0x00000000
root@am57xx-evm:~#

 All values are read zeros, I am not able to figure out the issue.

To use SDRAM as shared memory between ARM-DSP, am I supposed to do any configurations from ARM/DSP side?

Thanks,

Janardan

Hi, Janardan,

Isn't the OCMC used for the shared memory? If you are using OCMC, why is it the DDR memory at 0x81000000 dumped? Shouldn't you dump the ocmc2 memory at 0x40400000 or ocmc3 at 0x40500000?

Rex

HI Rex,

When I use 0x40300000 or 0x40400000 OCMC memories, I was observing kernel crash , so I wanted to check with the SDRAM as well, using SDRAM as shared memory is also fine for our requirement.

Please provide me details regarding usage of OCMC as shared memory and also on using SDRAM as shared memory.

I am not able to figure out the dependencies. I see that it is working on your setup from your post, I believe I am doing something wrong . Presently I am following below sequence.

1. Write to memory from DSP (dra7-dsp1-fw.xe66 loaded from linux through remote-proc)
2. Read back the memories through devmem2

Is there anything to do on DTS or any other dependencies from Linux end?
Is there anything to do in configuration file or resource table from DSP end?

Expecting your kind help.

Thanks,
Janardan

Hello Rex,

Sounds like an interesting issue.  

Would you please share a sample application that works on your setup which can be tried as is? Please provide the detail steps/changes required.

Appreciate your quick help.

- Rj

 

Janardan>>>
I am doing cache write back operation after the write from DSP end, from ARM I am not doing invalidate and as of my understanding that is not required from ARM end, correct me if I am wrong.

Rex,
Can you please comment on this? Thanks

Hi Rex,

Which version of Processor SDK linux are you using?

Thanks,

Janardan

Hi Rex,

Taking forward the conversation, we are still facing issue using SDRAM / OCMC as shared memory.

We tried to use L2S RAM as shared memory between DSP-ARM, L2S is internal to DSP sub-system and is working fine, DSP/Write -> ARM/Read and ARM/Write -> DSP/read is working fine on this memory.

Here is the sequence I followed.

1. Access L2S memory from DSP through a pointer and write to that memory.

2. From arm end ,converted the L2S memory address into Global address

3. Used this global address to read the memory

This is working as expected, but we need to get this shared memory working on SDRAM and OCMC as well, please help us figuring out the issue.

Thanks,

Janardan