View source for Tests:SCIF-FIFO

This document describes how to test FIFO behavior for the Renesas SCIF, SCIFA, SCIFB, and HSCIF serial ports.


== Kernel Version and Configuration ==

* arm32: shmobile_defconfig (you may want to enable CONFIG_CGROUPS)
* arm64: defconfig

By default, serial port DMA is disabled.
You can test either with DMA enabled:
<pre>
CONFIG_SERIAL_SH_SCI_DMA=y
</pre>
or disabled:
<pre>
# CONFIG_SERIAL_SH_SCI_DMA is not set
</pre>


== Hardware Environment ==

=== [[R-Car/Boards/Koelsch|Koelsch]] ===

* For testing transfers between SCIF3 and SCIFA5:
** Connect SCIF3 TXD (EXIO Connector C pin 38) to SCIFA5 RXD (EXIO Connector C pin 39)
** Connect SCIF3 RXD (EXIO Connector C pin 40) to SCIFA5 TXD (EXIO Connector C pin 37)
* For testing transfers between SCIFB0 and HSCIF1:
** Connect SCIFB0 TXD (EXIO Connector A pin 60) to HSCIF1 RXD (EXIO Connector A pin 72)
** Connect SCIFB0 RXD (EXIO Connector A pin 66) to HSCIF1 TXD (EXIO Connector A pin 53)

=== [[R-Car/Boards/Salvator-X|Salvator-X]] ===

* For testing transfers between SCIF3 and HSCIF3:
** Connect SCIF3 TXD (EXIO Connect D pin 21) to HSCIF3 RXD (EXIO Connect D pin 28)
** Connect SCIF3 RXD (EXIO Connect D pin 27) to HSCIF3 TXD (EXIO Connect D pin 30)


== Test Procedure ==

=== [[R-Car/Boards/Koelsch|Koelsch]] ===

Load all needed DT overlays:
<pre>
overlay add r8a7791-koelsch-exio-c-scif3.dtbo \
            r8a7791-koelsch-exio-c-scifa5-c.dtbo \
            r8a7791-koelsch-exio-a-scifb0.dtbo \
            r8a7791-koelsch-exio-a-hscif1.dtbo
</pre>

Set up a few convenience macros:
<pre>
scif3=/dev/ttySC3
scifa5=/dev/ttySC11
scifb0=/dev/ttySC12
hscif1=/dev/ttySC16
</pre>

Test transfers from HSCIF1 to SCIFB0:
<pre>
fifotest $hscif1 $scifb0 -s 1000000 -n 100
</pre>

Test transfers from SCIFB0 to HSCIF1:
<pre>
fifotest $scifb0 $hscif1 -s 1000000 -n 100
</pre>

Test transfers from SCIF3 to SCIFA5:
<pre>
fifotest $scif3 $scifa5 -s 1000000 -n 100
</pre>

Test transfers from SCIFA5 to SCIF3:
<pre>
fifotest $scifa5 $scif3 -s 1000000 -n 100
</pre>

Expected output for all four tests above (after ca. 12 seconds):
<pre>
MSG: 100, TX: 55208 bytes, RX: 25932 bytes
</pre>


=== [[R-Car/Boards/Salvator-X|Salvator-X]] ===

SCIF3 and HSCIF3 are already enabled by r8a7795-salvator-x.dts in renesas-drivers.
If you use a different tree, you have to make sure the right overlays have been loaded:
<pre>
overlay add r8a7795-salvator-x-exio-d-scif3.dtbo \
            r8a7795-salvator-x-exio-d-hscif3.dtbo
</pre>

Set up a few convenience macros:
<pre>
scif3=/dev/ttySC2
hscif3=/dev/ttySC3
</pre>

Test transfers from SCIF3 to HSCIF3:
<pre>
fifotest $scif3 $hscif3 -s 1000000 -n 100
</pre>

Test transfers from HSCIF3 to SCIF3:
<pre>
fifotest $hscif3 $scif3 -s 1000000 -n 100
</pre>

Expected output for all two tests above (after ca. 12 seconds):
<pre>
MSG: 100, TX: 55208 bytes, RX: 25932 bytes
</pre>


== References ==

=== Linux Kernel Source Tree ===

* Git repository: git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git
* Branches:
** renesas-drivers-2016-05-17-v4.6 (shows failures)
** topic/scif-fifo-v1 (fix for the above)
** renesas-drivers-2016-05-31-v4.7-rc1 (shows success)

Note: The DT overlays are not included in above source trees, so you have to merge the 'renesas-overlays' branch yourself to test on Koelsch.
Please see [[R-Car/DT-Overlays]] for more information about using DT overlays.

Hence for now I'm providing the following two branches, containing all prerequisites:
* fifotest-fail (shows failures)
* fifotest-ok (fixed)


=== Test Software ===

* https://github.com/geertu/fifotest
* https://github.com/geertu/sertest (for serial link integrity)


=== Samtec QTE Breakout Adapters ===

* [[Samtec-Breakout-Adapters]]


=== Udev rules ===

If you want to refer to serial ports by their hardware name (e.g. "/dev/scifa5"), you can use the following udev rules:

* "/etc/udev/rules.d/99-scif.rules" on Koelsch:
<pre>
ENV{DEVNAME}=="/dev/ttySC0", SYMLINK+="scif0"
ENV{DEVNAME}=="/dev/ttySC1", SYMLINK+="scif1"
ENV{DEVNAME}=="/dev/ttySC2", SYMLINK+="scif2"
ENV{DEVNAME}=="/dev/ttySC3", SYMLINK+="scif3"
ENV{DEVNAME}=="/dev/ttySC4", SYMLINK+="scif4"
ENV{DEVNAME}=="/dev/ttySC5", SYMLINK+="scif5"

ENV{DEVNAME}=="/dev/ttySC6", SYMLINK+="scifa0"
ENV{DEVNAME}=="/dev/ttySC7", SYMLINK+="scifa1"
ENV{DEVNAME}=="/dev/ttySC8", SYMLINK+="scifa2"
ENV{DEVNAME}=="/dev/ttySC9", SYMLINK+="scifa3"
ENV{DEVNAME}=="/dev/ttySC10", SYMLINK+="scifa4"
ENV{DEVNAME}=="/dev/ttySC11", SYMLINK+="scifa5"

ENV{DEVNAME}=="/dev/ttySC12", SYMLINK+="scifb0"
ENV{DEVNAME}=="/dev/ttySC13", SYMLINK+="scifb1"
ENV{DEVNAME}=="/dev/ttySC14", SYMLINK+="scifb2"

ENV{DEVNAME}=="/dev/ttySC15", SYMLINK+="hscif0"
ENV{DEVNAME}=="/dev/ttySC16", SYMLINK+="hscif1"
ENV{DEVNAME}=="/dev/ttySC17", SYMLINK+="hscif2"
</pre>

* "/etc/udev/rules.d/99-scif.rules" on Salvator-X:
<pre>
ENV{DEVNAME}=="/dev/ttySC0", SYMLINK+="scif2"
ENV{DEVNAME}=="/dev/ttySC1", SYMLINK+="scif1"
ENV{DEVNAME}=="/dev/ttySC2", SYMLINK+="scif3"
ENV{DEVNAME}=="/dev/ttySC3", SYMLINK+="hscif3"
ENV{DEVNAME}=="/dev/ttySC4", SYMLINK+="hscif4"
</pre>