Processor SDK Linux ICSS-EMAC User Space

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Overview

The ICSS_EMAC (Industrial Communications SubSystem Ethernet Media Access Controller) driver provides APIs to transmit and receive packets with a firmware based Ethernet switch that has been implemented on TI’s PRU-ICSS (Programmable Real-Time Unit Subsystem and Industrial Communication SubSystem) 32-bit RISC cores. The user space ICSS-EMAC driver has the same software architecture and features as the RTOS ICSS-EMAC, but implements the memory access and interrupt handling through Linux Userspace I/O (UIO) driver.


Software Stack

The picture below illustrates the software stack of ICSS-EMAC Linux user space. Majority of the upper layer components are common between RTOS and Linux user space, with the difference on Linux OS with the UIO driver vs. RTOS.


Icss-emac sw stack.png

Memory Access and Interrupt Handling through UIO

While RTOS can directly access memory locations, e.g., HW_RD_REG32(0x4b220000), Linux needs memory mapping of memory regions to user space, and this is done using the UIO driver with linux file-I/O like API such as open(), close(), read(), write(), and etc.

As for the interrupt handling, RTOS registers interrupt service routines (ISRs) that are triggered when an interrupt occurs, while Linux must have a thread that waits (read()) on the file descriptor for an interrupt. Device interrupts are accessed from Linux user-space, and linux file-I/O like API such as open(), close(), read(), write(), and etc. are used here also.

The picture below shows how the memory regions and interrupts are defined in kernel device tree, and how the application/driver can map and access the memory regions, as well as handle the interrupts through the UIO driver.

Icss-emac uio.png


Rebuild ICSS-EMAC in Linux User Space

Processor SDK Linux has packaged the pre-built binary for ICSS-EMAC LLD unit test, which can be found on filesystem at /usr/bin/icss_emacMainTest_[platform].out.

The source code of the ICSS-EMAC LLD and the unit test can be found at http://git.ti.com/keystone-rtos/icss-emac. The changes specific to Linux user space can be found by looking for the define of "__LINUX_USER_SPACE". The files to implement the UIO based memory access and interrupt handling are placed under the test/src/armv7/linux directory.

When there is need to modify the source code of the ICSS-EMAC LLD and/or the unit test, the LLD and the unit test can be rebuilt through Yocto recipes. In order to do so, please refer to Processor SDK Building The SDK to set up the build environment, and Processor SDK Yocto Recipes to bitbake the recipes and install the newly built packages for icss-emac-lld and icss-emac-lld-test.

For example, the commands below are for rebuilding icss-emac-lld and icss-emac-lld-test for AM57xx.

MACHINE=am57xx-evm bitbake icss-emac-lld
MACHINE=am57xx-evm bitbake icss-emac-lld-test

After the bitbake commands above are successfully done, the icss-emac-lld lib and the icss-emac-lld-test binaries can found from ./build/arago-tmp-external-linaro-toolchain/work/am57xx_evm-linux-gnueabi/icss-emac-lld/<ver_number>/packages-split/icss-emac-lld/usr/lib and ./build/arago-tmp-external-linaro-toolchain/work/am57xx_evm-linux-gnueabi/icss-emac-lld-test/<ver_number>/packages-split/icss-emac-lld-test/usr/bin directories, respectively.


Running ICSS-EMAC Unit Test in Linux User Space

ICSS-EMAC unit test demonstrates loopback capability by sending dummy broadcast packets, which are then looped back with loopback cables. Unit test registers receive packet callback routine with LLD to be called for RX packet. Call back routine will extract packet received, perform simple memory comparison against packet sent for integrity check. Unit test will iterate 10 times for packet transmission and reception check. It also demonstrates time trigger send (TTS) after broadcast packets send/receive are completed. At the end of unit test, "All tests have passed" will be printed on console.

ICSS-EMAC user space driver and unit test are now supported on multiple TI platforms, including

  • AM335x ICE V2
  • AM437x IDK
  • AM571x IDK
  • AM572x IDK
  • K2G ICE

The sections below describe the procedure and sample logs of running the ICSS-EMAC unit test on these platforms.

AM335x ICE V2

Before powering up the AM335x ICE V2 EVM, ensure that Pin 2 and Pin 3 of the two CPSW/ICSS Jumpers are connected. Location of these two jumpers can be found from http://processors.wiki.ti.com/index.php/AM335x_Industrial_Communication_Engine_EVM_Rev2_1_HW_User_Guide#Component_Positions.

  1. Plug in loopback cables to the two ICSS-EMAC ports of AM335x ICEv2 EVM
  2. On the filesystem under /boot directory, link am335x-icev2-pru-excl-uio.dtb as the default dtb file, i.e., am335x-icev2.dtb.
  3. Reboot the EVM
  4. Run "icss_emacMainTest_am335x.out"


AM437x IDK

  1. Plug in loopback cables to the two ICSS-EMAC ports of AM4 IDK EVM
  2. On the filesystem under /boot directory, link am437x-idk-pru-excl-uio.dtb as the default dtb file, i.e., am437x-idk-evm.dtb
  3. Reboot the EVM
  4. Run "icss_emacMainTest_am437x.out"


AM571x IDK

First ensure that Jumper J51 is not placed. That selects between LCD function (J51 placed) and ICSS1 Ethernet (J51 removed). This also indicates that ICSS-EMAC unit test cannot run with LCD connected on the AM571x IDK board.

  1. Plug in four loopback cables to the four ICSS-EMAC ports
  2. On the filesystem under /boot directory, link am571x-idk-pru-excl-uio.dtb as the default dtb file, e.g., am571x-idk.dtb when using AM571x IDK without LCD display
  3. Reboot the EVM
  4. Run "icss_emacMainTest_am571x.out"


AM572x IDK

  1. Reserve core 1 for the unit test, and this can be done by adding "isolcpus=1" in uEnv.txt (under boot partition).
  2. On the filesystem under /boot directory, link am572x-idk-pru-excl-uio.dtb as the default dtb file, e.g., am572x-idk.dtb.
  3. Reboot the EVM.
  4. Before running the unit test, open an SSH window to the EVM.
  5. From console 1: run "icss_emacMainTest_am572x.out". It will display a message and wait for the keyboard input.
  6. From console 2: set affinity of the unit test process to core 1: first find pid from the output log of "ps aux | grep icss", and then run "taskset -p 2 [pid]".
  7. From console 1: continue running "icss_emacMainTest_am572x.out" by pressing any keys.


K2G ICE

  1. Plug in loopback cables to the four ICSS-EMAC ports of K2G ICE EVM
  2. On the filesystem under /boot directory, link keystone-k2g-ice-pru-excl-uio.dtb as the default dtb file, i.e., keystone-k2g-ice.dtb
  3. Reboot the EVM
  4. Run "icss_emacMainTest_k2g.out"


Sample Log from AM572x IDK

  • Console 1
root@am57xx-evm:~# icss_emacMainTest_am572x.out
Set core affinity before continuing the process: taskset -p 2 [pid]
Enter character:


  • Console 2
root@am57xx-evm:~# ps aux | grep icss
root      1425  0.0  0.0   1472  1068 ttyS2    S+   18:24   0:00 icss_emacMainTest_am572x.out
root      1427  0.0  0.0   1968  1100 pts/0    S+   18:30   0:00 grep icss
root@am57xx-evm:~# taskset -p 2 1425
pid 1425's current affinity mask: 3
pid 1425's new affinity mask: 2


  • Console 1 after hitting any key to continue the test:
ICSS_EMAC_testTaskPruss2: ICSS_EMAC_testPgVersion: 0x2
ICSS_EMAC_testTaskPruss2: PRU2 ETH0: LINK IS UP, eth0 state: 1, link up count: 1
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH0): 0
ICSS_EMAC_testTaskPruss1(PRU2 ETH0): received pkt: 0
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH0): 1
ICSS_EMAC_testTaskPruss1(PRU2 ETH0): received pkt: 1
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH0): 2
ICSS_EMAC_testTaskPruss1(PRU2 ETH0): received pkt: 2
ICSS_EMAC_testTaskPruss1(PRU2 ETH0): received pkt: 3
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH0): 3
ICSS_EMAC_testTaskPruss1(PRU2 ETH0): received pkt: 4
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH0): 4
ICSS_EMAC_testTaskPruss1(PRU2 ETH0): received pkt: 5
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH0): 5
ICSS_EMAC_testTaskPruss1(PRU2 ETH0): received pkt: 6
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH0): 6
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH0): 7
ICSS_EMAC_testTaskPruss1(PRU2 ETH0): received pkt: 7
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH0): 8
ICSS_EMAC_testTaskPruss1(PRU2 ETH0): received pkt: 8
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH0): 9
ICSS_EMAC_testTaskPruss1(PRU2 ETH0): received pkt: 9
ICSS_EMAC_testTaskPruss2: PRU2 ETH1: LINK IS UP, eth0 state: 1, link up count: 2
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH1): 0
ICSS_EMAC_testTaskPruss1(PRU2 ETH1): received pkt: 10
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH1): 1
ICSS_EMAC_testTaskPruss1(PRU2 ETH1): received pkt: 11
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH1): 2
ICSS_EMAC_testTaskPruss1(PRU2 ETH1): received pkt: 12
ICSS_EMAC_testTaskPruss1(PRU2 ETH1): received pkt: 13
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH1): 3
ICSS_EMAC_testTaskPruss1(PRU2 ETH1): received pkt: 14
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH1): 4
ICSS_EMAC_testTaskPruss1(PRU2 ETH1): received pkt: 15
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH1): 5
ICSS_EMAC_testTaskPruss1(PRU2 ETH1): received pkt: 16
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH1): 6
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH1): 7
ICSS_EMAC_testTaskPruss1(PRU2 ETH1): received pkt: 17
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH1): 8
ICSS_EMAC_testTaskPruss1(PRU2 ETH1): received pkt: 18
packet transmission complete for packet(ICSS_EMAC_TEST_PRU2ETH1): 9
ICSS_EMAC_testTaskPruss1(PRU2 ETH1): received pkt: 19

============================================================
Initiating TTS tests on ICSS_EMAC_TEST_PRU2ETH0 and ICSS_EMAC_TEST_PRU2ETH1
============================================================
TTS Port 1: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 799999 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 2: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 799999 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 1: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 800000 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 2: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 799999 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 1: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 799999 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 2: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 799999 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 1: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 799999 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 2: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 799999 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 1: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 799999 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 2: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 799999 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 1: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 799999 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 2: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 799999 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 1: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 799999 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 2: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 799999 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 1: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 800000 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 2: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 800000 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 1: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 800000 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 2: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 800000 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 1: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 800000 ns
Maximum Jitter: 40 ns
============================================================
TTS Port 2: Test Passed!!
Programmed Cycle Period: 800000 ns
Average Cycle Period: 800000 ns
Maximum Jitter: 40 ns
============================================================
TTS tests finished on ICSS_EMAC_TEST_PRU2ETH0 and ICSS_EMAC_TEST_PRU2ETH1
============================================================
Done with PRU-ICSS Instance 2 Testing

PRU-ICSS STATS for PRU2ETH0
txBcast:0xa
txMcast:0x18a88
txUcast:0x0
txOctets:0x789d80
rxBcast:0xa
rxMcast:0x18a88
rxUcast:0x0
rxOctets:0x789d80
tx64byte:0x186aa
tx65_127byte:0x0
tx128_255byte:0x0
tx512_1023byte:0x0
tx1024byte:0x3e8
rx64byte:0x186aa
rx65_127byte:0x0
rx128_255byte:0x0
rx512_1023byte:0x0
rx1024byte:0x3e8
lateColl:0x0
singleColl:0x0
multiColl:0x0
excessColl:0x0
rxMisAlignmentFrames:0x0
stormPrevCounter:0x0
macRxError:0x0
SFDError:0x0
defTx:0x0
macTxError:0x0
rxOverSizedFrames:0x0
rxUnderSizedFrames:0x0
rxCRCFrames:0x0
droppedPackets:0x0
txOverFlow:0x0
txUnderFlow:0x0
sqeTestError:0x0
TXqueueLevel:0x0
CSError:0x0


PRU-ICSS STATS for PRU2ETH1
txBcast:0xa
txMcast:0x18a88
txUcast:0x0
txOctets:0x789d80
rxBcast:0xa
rxMcast:0x18a88
rxUcast:0x0
rxOctets:0x789d80
tx64byte:0x186aa
tx65_127byte:0x0
tx128_255byte:0x0
tx512_1023byte:0x0
tx1024byte:0x3e8
rx64byte:0x186aa
rx65_127byte:0x0
rx128_255byte:0x0
rx512_1023byte:0x0
rx1024byte:0x3e8
lateColl:0x0
singleColl:0x0
multiColl:0x0
excessColl:0x0
rxMisAlignmentFrames:0x0
stormPrevCounter:0x0
macRxError:0x0
SFDError:0x0
defTx:0x0
macTxError:0x0
rxOverSizedFrames:0x0
rxUnderSizedFrames:0x0
rxCRCFrames:0x0
droppedPackets:0x0
txOverFlow:0x0
txUnderFlow:0x0
sqeTestError:0x0
TXqueueLevel:0x0
CSError:0x0

All tests have passed