[meta-xilinx] Zedboard - I'm not eble to set i2c on PS

[Luca Ceresoli]

Hi Jek,

On 27/06/19 17:18, Jek F. wrote:
> Hi, and thanks for your answer.
> 
> Using the oscilloscope I verified that the line is always low, i
> inserted the pull-ups but there is no data transfer and the error remains.
> I realized that until now I didn't know i had to insert the ps7 files
> into the project.

Definitely needed.

> So i tried to create a custom layer in which i recreated the meta-xilinx
> structure (meta-xilinx/meta-xilinx-bsp/platform-init):
> ex:
> 
> meta-mylayer/recipes-bsp/platform-init/files/zedboard-zinq7/ps7init_gpl.h
> meta-mylayer/recipes-bsp/platform-init/files/zedboard-zinq7/ps7init_gpl.c

zinq7 -> zynq7

> generated by SDK.
> 
> In the meta-mylayer/recipes-bsp/platform-init/platform-init.bbappend
> file i inserted:
> 
> COMPATIBLE_MACHINE = "$^"
> COMPATIBLE_MACHINE_zedboard-zynq7 = "zedboard-zynq7"
> 
> FILESEXTRAPATHS_prepend := "${THISDIR}/files:"
> 
> SYSROOT_DIRS += "${PLATFORM_INIT_DIR}"
> 
> SRC_URI += "file://zedboard-zynq7/ps7_init_gpl.c"
> SRC_URI += "file://zedboard-zynq7/ps7_init_gpl.h"
> 
> do_compile() {
>      :
> }
> 
> do_install_append() {
> install -d ${D}${PLATFORM_INIT_DIR}
> install –m 06444 ${THISDIR}/files/zedboard-zynq7/ps7_init_gpl.c
> ${D}${PLATFORM_INIT_DIR}/
> install –m 06444 ${THISDIR}/files/zedboard-zynq7/ps7_init_gpl.h
> ${D}${PLATFORM_INIT_DIR}/
> }

I don't know the platform-init, but I'd do the usual yocto debugging
steps: 'bitbake -e platform-init' to see if yout variables are correctly
parsed; check the logs in tmp/work/zedboard-zynq7*/platform-init/*/temp;
check if the correct files (with the correct content) have been copied
in tmp/work/zedboard-zynq7*/platform-init/*/ etc.

Also I think your bbappend file above contains too much. Most of if
should come from the .bb file, you should add almost nothing, possibly
not even SRC_URI. But as I said I don't know that recipe, other people
here will probably know better. Or you can track on your own what the
recipe does: the ps7_init files have to reach the U-Boot source code and
get built in its SPL.

> Thanks.
> 
> Il giorno mar 25 giu 2019 alle ore 12:49 Luca Ceresoli
> <luca at lucaceresoli.net <mailto:luca at lucaceresoli.net>> ha scritto:
> 
>     Hi Jek,
> 
>     On 25/06/19 11:00, Jek F. wrote:
>     > Hi, i'm a beginner and an autodidact. This is my first post here.
>     > I'm trying to address i2c on Zedboard PS without luck, using
>     Vivado, SDK
>     > and Yocto Project.
>     >
>     > My current situation is:
>     >
>     > With Vivado:
>     >
>     > 1) Create Project -> RTL Project
>     >
>     > 2) Create block design -> Add IP -> ZYNQ7 Processing System
>     >
>     > 3) Run Block Automation
>     >
>     > 4) In "MIO Configuration" i enabled i2c0 on "MIO 10 11" and i2c1
>     on "MIO
>     > 12 13", i clicked on "Create HDL Wrapper..." and then i generated the
>     > bitstream
>     >
>     > 5) File -> Export -> Export Hardware -> Include bitstream ->
>     Launch SDK
>     >     - then i converted the bitstream .bit in .bin (fpga.bin) with an
>     > external tool
>     >
>     > 6) In SDK i generate new board support package
>     >     - File -> New -> Board Support Package -> device tree (for this i
>     > downloaded a plugin to generate DTS)
>     >     - Then i choose kernel 2018.3.
>     >     - This generated these files: pcw.dtsi, skeleton.dtsi, system.dts,
>     > system-top.dts, zynq-7000.dtsi
>     >
>     > With yocto:
>     >
>     > 1)I've cloned yocto project (poky 2.6.2 thud)
>     >
>     > 2)I've cloned layer meta-openembedded and meta-xilinx.
>     >
>     > I've modified then file bblayers.conf adding in it:
>     >     /home/jksandek/poky/meta-openembedded/meta-oe \
>     >     /home/jksandek/poky/meta-xilinx/meta-xilinx-bsp \
>     >
>     > 3) I've added the file local.conf
>     >     MACHINE ??= "zedboard-zynq7"
>     >     ...
>     >     IMAGE_INSTALL_append = " rsync"
>     >     IMAGE_INSTALL_append = " busybox"
>     >     IMAGE_INSTALL_append = " openssh"
>     >     IMAGE_INSTALL_append = " nano"
>     >     IMAGE_INSTALL_append = " i2c-tools"
>     >     ENABLE_I2C = "1"
>     >     INHERIT += "rm_work"
>     >
>     > 4) Then i have created a new layer "meta-dts" with the following
>     folder
>     > tree:
>     >
>     >     meta-dts
>     >     ├── conf
>     >     │     └── layer.conf
>     >     ├── COPYING.MIT
>     >     └── recipes-kernel
>     >            └── linux
>     >                    ├── linux-xlnx
>     >                    │      ├── myconfig.cfg
>     >                    │      └── zedboard-zynq7
>     >                    │            ├── pcw.dtsi
>     >                    │            ├── skeleton.dtsi
>     >                    │            ├── system.dts
>     >                    │            ├── system-top.dts
>     >                    │            └── zynq-7000.dtsi
>     >                    └── linux-xlnx_%.bbappend
>     >    
>     >     -in "linux-xlnx_%.bbappend" i inserted:
>     >    
>     >     SRC_URI +=
>     "file://system-top.dts;subdir=git/arch/${ARCH}/boot/dts"
>     >     SRC_URI += "file://pcw.dtsi;subdir=git/arch/${ARCH}/boot/dts"
>     >     SRC_URI +=
>     "file://zynq-7000.dtsi;subdir=git/arch/${ARCH}/boot/dts"
>     >     SRC_URI_append += "file://myconfig.cfg"
>     >
>     >     -in "myconfig.cfg" i inserted:
>     >    
>     >     CONFIG_I2C_XILINX=y
>     >     XILINX_I2C=y
>     >     I2C_CADENCE=y
>     >     CONFIG_I2C=y
>     >
>     > 5) Then i added this layer in bblayers.conf
>     >
>     > 6) Start bitbake with:
>     >     - bitbake core-image-minimal
>     >
>     > 7) At the end of the bitbake i've added the following files in the SD
>     > BOOT partition
>     >     - boot.bin
>     >     - fpga.bin
>     >     - system-top.dtb
>     >     - u-boot.img
>     >     - uImage
>     >     - uEnv.txt
>     >
>     > 8) In the rootfs partition i've added and unzipped the following file:
>     >     - core-image-minimal-zedboard-zynq7.tar.gz
>     >
>     > 9) At the end i started the zedboard and once i logged in i've typed:
>     >     - i2cdetect -r -y 0
>     >
>     >
>     >     but this return something like:
>     >
>     >     root at zynq:~# i2cdetect -y -r 0
>     >     0 1 2 3 4 5 6 7 8 9 a b c d e f
>     >     00: cdns-i2c e0004000.ps7-i2c: timeout waiting on completion
>     >     -- cdns-i2c e0004000.ps7-i2c: timeout waiting on completion
> 
>     On the software side Linux knows about your controller, this looks good.
>     But does the hardware (including FPGA) do what you expect?
> 
>     First things first: check that the i2c controller really exists in FPGA.
>     devmem2 is the simplest tool to do it: try to read registers at
>     0xe0004000 + the offsets in the i2c controller datasheet. Do you read
>     the values expected according to the datasheet?
> 
>     "timeout waiting on completion" suggests nobody is pulling the line
>     high. What is connected on the MIO 10 and 11 pins? Is there a pull-up
>     resistor there?
> 
>     Then check if the lines are actually at the intended electrical levels:
>      - SCL+SDA high when idle (a multimeter is enough here)
>      - change low/high when in use, at the expected frequency (possibly
>        with an oscilloscope, but a logical analyzer is quite OK as well)
>      - have reasonably steep rising edges when in use (with an oscilloscope)
> 
>     I hope it helps,
>     -- 
>     Luca
> 
> 

-- 
Luca