Nishanth' tech rambles

So omapzoom folks have a tutorial hour now, some really cool topics get caught up here.. this week: · Android on OMAP Overview and Resources · DSP Bridge Overview · OpenEmbedded Overview it is a webex (works on most OSes including a linux PC) + teleconf -> large number of access numbers from around the world more information here . the OMAP tutorial hour (including the previous presentations - which by the way explains kernel process from TI) are available here .

Googling around, I found this beautiful article that gives excellent explanation of how Adaptive Voltage behaves in the system. by the way, this is going to be part of my rewrite of smart reflex driver to make the voltage infrastructure a lot more cleaner and easy to use. General flow I am thinking is as follows(will change ofcourse): voltage driver |------------> No SR PMICs implementation thru regulator framework perhaps. \-------> Smart reflex driver |----> PMIC interface (for class 0 devices) |-----------------------------------\ \-----> Voltage processor driver -> Voltage controller driver Ofcourse things might change as I move on with the implementation (I need to think a little more on this), but once I am done, you should be able to see it here

After a long while of staying off linux-omap, been watching it rather closely recently.. here are some interesting stuff I saw this month: Power Management: Operating points and general PM strategy for handling for various silicons here Silicon Feature support for OMAP3 here New silicon support: OMAP35xx and 36xx support being introduced. Discussion on memory and cache issue here ETM, ETM support here few new PMIC - 6030 and 5031 hints of wl1251 support getting upstream IO_ADDRESS is dead use io_remap like the rest of the world spring cleaning of omap850/730 series and of course a bunch of stuff I have missed posting here such as move to 2.6.32-rc4 by Tony and Kevin, both pushing out patches to mainline etc.....

High time I "ported" my posts from facebook back here.. so here it goes Some really bad code stories: shared by rob clark - how bad can some code go?? http://thedailywtf.com/Articles/The-Shenanigans-Handler.aspx Aint this cool: http://arstechnica.com/web/news/2009/09/horrifically-bad-software-demos-become-performance-art.ars Techno Curios: Tired of fullspeed, highspeed, lowspeed?? how about superspeed?? tired of acronymns already?? http://www.pcworld.com/article/172757/wheres_usb_30.html Search for my cheap oscilloscope goes on: http://www.micahcarrick.com/06-06-2006/pc-sound-card-oscilloscope-linux.html http://www.fpga4fun.com/digitalscope.html Hacks 'nd bytes: PS3 back with Hulu.. http://www.ypass.net/blog/2009/06/got-a-ps3-want-hulu-back-easy-enough/

drawtime This is kinda a cool app that runs on ubuntu to draw timing diagrams as follows: Example(from the drawtime website): CS1 = 1, OE = 1, ADDR = X, DATA = Z. CS1 = 0, OE = 0, ADDR = "". OE -tOE> DATA = ""; CS1 -tCS1> DATA; ADDR -tACC> DATA. OE = 1, CS1 = 1, ADDR = X. CS1 -tH> DATA = Z; OE -tH> DATA; ADDR -tH> DATA. and you can now generate all those cool waveforms without having to worry about did you get the lines right etc.. more such cool stuff here

Looking through the beagleboard facebook group , Saw two interesting points: Flash Lite 3.1 evaluation version for Beagleboard For all the Beagleboard fans out there, we’ve created an evaluation version of Flash Lite 3. This is a fully functional version of Flash Lite that times out in 3 minutes. It is built on Angstrom Linux distribution and requires X. Please email me if you are looking for more information or are interested in having one. I should mention that OMAP 3530 (ARM Cortex A8) is a powerful CPU and seems to handle graphics as well as video very well." How to build Valgrind for Beagleboard 1) Get Valgrind source code from SVN using revision 9648 and 1888 for VEX svn co -r 9648 svn://svn.valgrind.org/val grind/trunk cd VEX svn update -r 1888 2) Download the patch here http://bugsfiles.kde.org/a ttachment.cgi?id=32348 3) Apply the patch into the source code cd valgrind patch -p1 4) Run autogen.sh to run autotools 5) Configure the source code ./configure --host=arm-angst...

here are the sessions in the conference: http://www.embeddedlinuxconference.com/elc_europe09/sessions.html Includes Sascha and my personal fav - u-boot v2 .

Finally.... here it is!!! patches for u-boot to be send straight to u-boot mailing list .

Wow.. a blast of new sites for omapzoom.. And then I see this on the new omapzoom google groups !!! * MPEG4 Video Dec * H263 Video Dec * JPEG Dec * JPEG Enc * AAC Dec https://gforge.ti.com/gf/project/openmax/frs/?action=index And you also now have a wiki for omap

Got this link from a colleague - kinda useful if you would like to use it for your own purposes.. quote from the site: PLATO is a tool for displaying and analyzing software traces from an application being debugged. It connects to TTIF (libttif.so, included) which provides a lower overhead replacement for printf(), so as to minimize the chance that timing related bugs disappear when you enable debug traces, and also some binary trace APIs. PLATO can be running on a separate PC from the application being debugged, making it suited for embedded development. PLATO will decode/filter/display/visualize the traces

I have a confession to make: I am fanatic about clean code. I like it simple and I like it elegant. Few days back, I had a chat on linux omap mailing list on what I'd dream to see instead of a half a dozen cpu_has_feature_XYZ() APIs in the system.. The thought is more of this form: Some sort of infrastructure which is common to all silicons,platforms exist which provides method to register the tuple (silicon_rev_id | ip_module_rev_id, feature_errata_id) Specific drivers such as DMA, I2C, McBSP, PRCM etc.. on registration provides to the system the an array of tuples for that device. Platform on bootup provides the platform_data to the driver, which allows the driver to start, but now, it can also detect cpu_rev and can grap it's own IP Module rev from it's own register.. -> that is provided to the infrastructure Every time there is a need to check to enable/disable feature/errata, all the code needs to do is: if (is_enabled(dev, OMAP3_ISP) ) { do my stuff; } is...

Finally irritated with a bunch of CaMELcASinG, decided to write a small script albeit not too clean or optimized for the job of a search and destroy Since it is weird to write my own c interpreter to find the right targets to replace, I use output of ctags to generate tags file. if you are using kernel, you could just do a make tags to get the same output file. #!/bin/bash # Silly little script to replace CaMELCaSInG to lower_casing # Half a zillion thoughts later, # why not use ctags which has c interpreter already to do # function identification for us? if [ ! -r 'tags' ]; then echo "Sorry.. no tags file!" exit 1 fi if [ ! -r "$1" ]; then echo "I need a directory or a file for replacing.." exit 2 fi DIR_FILE=`echo "$1"|sed -e "s/\//\\\//g"` # tags have the following notation in field 4 (tab seperated) # e - enum value # d - define # f - function # F - File itself # g - enum type # m - structure parameter # p - prototype # r...

Kevin (PM) has put some cool stuff up on elinux page. may want to check it out..

Check this script out: for i in /sys/devices/system/cpu/cpu[0-9]; do echo $i `cat $i/cpufreq/scaling_governor`; done and see here for a description and this for a bit of history

Been feeling guilty of not blogging the last few months.. anyways, here is something of interest. For all those interested, see here LinuxCon takes place on Sept 21-23 -> registration is running if you like to take part in. there is also bunch of parallel conferences happening. see the list here what would really be interesting for OMAP is the linux plumber's conf and Han's new V4l2 plan Be there if you would like to see a new architecture for OMAP3 and beyond taken care in new spec of V4l2...

here is something i just saw -> kinda nice handy scripts useful.. Example A-7. behead : Removing mail and news message headers Example A-8. ftpget : Downloading files via ftp

beagleboard.org has already a pretty active community in linkedin.. the following news items were picked up from the groups' Cloumnist update ( ;) thank you.. great job by the way): GL to GLES converter announced http://code.google.com/p/gl-wes-v2/ Good for Pandora, the OMAP3 based gaming platform Recommend Link: http://code.google.com/p/gl-wes-v2/ White paper: Power-management techniques for OMAP35x From: E-R: RSS Columnists | May 26, 2009 TI's OMAP3 application processors address the need for low power without sacrificing performance. Static power management idles a system in a power-efficient state until processing is required, while active power management adjusts More » White paper: Power-management techniques for OMAP35x Link: http://focus.ti.com/general/docs/gencontent.tsp?co...

Thanks to Sergio Aguirre a quick HOWTO: Configure Ubuntu 8.10 for VPN access ( for Cisco vpn ) Basic Requirements : Make sure you have the latest patches and updates for Ubuntu 8.10: sudo apt-get update sudo apt-get upgrade sudo apt-get install vpnc network-manager-vpnc Configuration: 1. Go to System > Preferences > Network Configuration 2. Select VPN tab 3. Click on Add button at the right side of the list 4. choose a vpn connection type: Cisco compatible vpn(vpnc) 5. click on create 6. Enter the following configuration (Other than the specified, leave everything else unchecked): Connection name: CorporateName Connect automatically: enable the checkbox if you would like it to.. Gateway: VPN GATEWAY Group name: VPN GROUP User password: my_user_id Group password: myPassword User name: 5. Click on 'OK' Enabling/disabling VPN access: 1. Left click on network icon in upper bar (next to the clock) 2. Go to VPN connections 3. Select CorporateName for enabling, or Disconnect f...

yes, we have heard of openOCD, Lauterbach, yet till date, I personally have'nt been able to use CCS to debug linux.. This post gives an interesting saga for those interested Warning : it is a little lengthy post, so as of the time of posting: Summary - CCS4 has support for linux kernel aware debugging, and unfortunately there is a small glitch of support of kernels 2.6.26 and above - the ccs team is working on a fix at this point.. hopefully we will have a full soln soon.. Thanks to John in deligently following up on this..

The post is a derivative of the omapzoom wiki page . Disclaimer: my mastery of the wiki tags are dismal.. apologies... some day i hope to have time to post it here Many new developers have been stumped when they need to use git-send-email in corporate environment – usually, if not as a norm, ms exchange servers form the backbone of such an email server system. This page was written based on one of such requirements. To get started, we shall consider common scenarios: a) Setting up a mail forwarding system with postfix on ubuntu b) Setting up a mail forwarding system on a fedora machine c) Using msmtp for using gmail a. to send a patch using a gmail ID b. to send a patch using your corporate ID but through gmail Postfix on Ubuntu – mail forwarding For setting up postfix, you need: a) A mail relay server which will allow your machine to talk to it -> speak to your IT representatives/ other developers sitting next to you b) Super user privileges on the machine you are working on. Step...

TI has a engineer to engineer forum here: http://e2e.ti.com/ forums this allows folks to: a) Get a direct and quick answer for a technical question b) lookup and search for old solutions which might help current problems one might face. Some of the interesting forums are: Code Composer Studio OMAP Application Processor Power Management IC such as TWL5030 TPS derivatives it even allows you to have a email notification and bunch of usual stuff..

Felipe C recently published gst-dsp Source: http://github.com/felipec/gst-dsp/tree/master Webpage: http://code.google.com/p/gst-dsp/ This is an alternative to the gstreamer plugins of gstreamer on TI Davinci and OMAP and openmax for OMAP gstreamer for TI Davinci and OMAP builds on top of dsplink while openMAX for OMAP builds on top of dspbridge -> interestingly gst-dsp builds on top of dspbridge. Try and do comment.. and dont forget to send your patches ;).. I have'nt had much chance to dig much into this new code yet -> but it sure looks sleek and full of potential

This news article was interesting.. hmm... how long before we see the first products in the market in the world of wireless devices?? munching time ;)

Background: Excerpts from the thread here A detailed presentation done by Richard Woodruff can be found here To start this discussion, think what OMAP really is.. OMAP is made of multiple small parts inside it (peripherals) - each peripheral can be individually shut off or switched on as need be. OPP or Operating Points: In fact OMAP could also be used like a car gear, if you need higher processing power, switch to a different "operating point". Each of these operating points is a set of voltage and frequencies that each peripherals and OMAP functions at -> usually the main peripherals of interest from a speed perspective are ARM and DSP, but like a car, when you speed up, you will consume more power.. [BUT unlike a car, during operation, OMAP's carbon footprin t is pretty tiny] Suspend/Resume: Since OMAP is also made up of various peripherals, you can switch off many of these peripherals when not in use, in fact you can have many levels of "switch off" = re...

[discussion thread here ] Few days back looking at OMAP3430 Public TRM I found the section 26.4.8.2(page 3427), it was exciting to see what possibilities lay here.. a little more digging later and few hours of coding later, figured out that by adding a certain data as a prefix to the real image, we can boot u-boot or for that matter any image straight from NAND flash into sdram.. essentially this is what x-loader does, only that OMAP3430 ROMCode already has that feature.. What exactly is Configuration Header(CH)? CH is a set of register values to the critical OMAP registers that define how the clocks, sdram controller, gpmc controller, mmc controllers are configured.. it is more like an array of register values - you fill them up with the correct values, and store the load address you would like the resultant image to load up, bingo, we have the image booting off that location.. There are few of these structures that are defined in the TRM which has a detailed description on the real...

saw this script and literally fell in love with it ;).. just changed the interpreter to /usr/bin/python, ./imap.py -a -e --server "IMAPSERVER:993" -u "MyID" -f "INBOX/OPENSOURCE/Linux-OMAP" and bingo give my password and it saves the entire folder as INBOX.OPENSOURCE.Linux-OMAP.mbox -> search in vi for ^From: and bingo you can copy entire patch files for git am to use.. ;) meanwhile you can easily split the mbox to maildir (multiple files) using mbox2maildir [Update] I thought it was a good idea, instead of trusting msexchange wordwrapping everything around... I am pretty darn irritated and switched to using mutt instead :(.. except I am DUMB.. i could have used the 'e' and saved what i see where ever i wanted it to be... :(... mutt is pretty darn easy!! all i needed to do was setup a ~/.muttrc as follows: set realname='Name' set from="Name <MAILID@SOME.COM>" set imap_user="ID" set imap_pass=Password set folder...

I have a windows laptop and a ubuntu desktop sitting next to each other and i would like to use my keyboard and mouse accross both without switching accross... here is the solution: SYNERGY !!! step 1 - ubuntu: sudo apt-get install synergy vim ~/.synergy.conf section: screens winlaptop: linuxserver: end section: links winlaptop: right = linuxserver linuxserver: left = winlaptop end Winlaptop is the name of my windows machine -> ipconfig /all should show the HOSTNAME for the same. linuxlaptop is the name of my machine without all the .x.y.z suffix.. Note the left and right depends on where your laptop and desktop sits.. suite which ever you want.. you can have multiple boxes if you like too... just sync them up in the config above.. next you need to get synergy start up when your login happens, you can do it multiple ways -> the one i did was to setup a short cut in my desktop for use when i want it.. - the short cut is to "synergys --config synergy....

> it is interesting why you write at the end of the email? > is this an email style? There are three styles of email replies that I follow: a) Follow bottom posting -> this is used by most linux opensource community : http://www.arm.linux.org.uk/mailinglists/etiquette.php#e3 b) For internal emails with respect to a topic, I retain top posting - since it can get forwarded to others who have no clue about the previous discussions, as bottom posting will remove the previous mail context. c) Mix of both - esp in internal email discussions -> this is when there is multiple responses -> in which case, I copy the contents of the email and paste it again in body of my reply to it. This allows: i) for people interested in the discussion to get the exact context of my reply without having to refer to the mailchain below to remember what they said.. ii) for people who get the email forwarded to get a context of the email by reading the previous chain.. general style I follow for...

Tired of setting up and switching ports in minicom and want something simple? welcome to picocom setup a script such as ~/bin/ttyUSB0 picocom -f n -p n -b 115200 -i -r -l /dev/ttyUSB0 and next time, just run ttyUSB0 and viola u have a terminal.. ctrl+a followed by ctrl+q quits..

With the recent merge of mtdparts patch for beagleboard u-boot Texas Instruments X-Loader 1.4.2 (Jan 30 2009 - 19:16:17) Loading u-boot.bin from nand U-Boot 2009.03-00325-gf75a729 (Apr 09 2009 - 13:36:05) OMAP3530-GP rev 2, CPU-OPP2 L3-165MHz OMAP3 Beagle board + LPDDR/NAND DRAM: 256 MB NAND: 256 MiB In: serial Out: serial Err: serial Board revision C Die ID #0a8600030000000004013f780600a00e OMAP3 beagleboard.org # you can now do cool things without having to remember the offsets of which partition was where.... (lets say you want to copy the kernel to nand flash) Step1: setup the partitions OMAP3 beagleboard.org # mtdparts default Step 2: erase the nand flash for kernel partition OMAP3 beagleboard.org # nand erase kernel NAND erase: device 0 offset 0x280000, size 0x400000 Erasing at 0x660000 -- 100% complete. OK Step 3: copy the kernel from RAM to the kernel partition in nand flash: OMAP3 beagleboard.org # nand write 0x80000000 kernel NAND write: device 0 offset 0x280000, si...

The following instructions are for 2.6.28 linux omap pm branch + tidspbridge Few links: * http://gitorious.org/projects/tidspbridge/repos/mainline - TIDSP Bridge codebase * http://patchwork.kernel.org/project/linux-omap/list/?q=DSP - pending patches on linux-omap mailing list * http://git.kernel.org/?p=linux/kernel/git/khilman/linux-omap-pm.git;a=summary - kevin's tree for Power management Steps: git clone git://git.kernel.org/pub/scm/linux/kernel/git/khilman/linux-omap-pm.git cd linux-omap-pm git checkout -b pm-2.6.28 --track origin/pm-2.6.28 git checkout -b tidspbridge git pull git://gitorious.org/tidspbridge/mainline.git tidspbridge-pm-2.6.28 make omap_3430sdp_defconfig for powermanagement: make CONFIG_OMAP_PM_SRF=y CONFIG_MPU_BRIDGE=m or y which ever is your preference.. enable BRIDGE_DVFS as y make uImage;make modules and bingo you should have arch/arm/mach-omap2/dspbridge.ko and arch/arm/mach-omap2/dspbridge.ko if you have dspbridge as a a module ;)... insmod dspbridge.ko ...

almost missing office hour due to jetlag is not a nice idea.. hence wrote this nonsense little script, which would stream a shoutcast stream while waiting to kick me up screaming.. Now, why should I suffer alone? :D.. #!/bin/bash #Choose your favourite stations from shoutcast.com (net radio) LINK="http://yp.shoutcast.com/sbin/tunein-station.pls?id=6063" if [ $# -eq 0 ]; then echo "usage $0 wakeup_duration" echo "wakeup_duration: wakeup after how long? 6 hours, 1 hour, 20 mins etc. or even 5am tomorrow.." exit 1 fi NOW_SEC=$(date +%s) WAKEUP_SEC=$(date +%s --date="$*") if [ $? -ne 0 ]; then echo "oopss.. i dont think date understands $*" exit 2 fi if [ $NOW_SEC -gt $WAKEUP_SEC ]; then SLEEP_SEC=$(( $NOW_SEC - $WAKEUP_SEC)) echo "Do you wish to wakeup $SLEEP_SEC seconds previously??.." echo "Sorry cant help you with that.. :(" exit 3 fi SLEEP_SEC=$(( $WAKEUP_SEC - $NOW_SEC)) echo "NOW=$NOW_SEC WAKE=$WAKEU...

The following check list was compiled based on a discussion here a) Did you check if the device id of the device is in TRM under supported devices? -> ROM Code should support this device if it should ever boot.. b) Did you read your CTRL_STATUS register and verify the SYSBOOT boot sequence in TRM -> is NAND in the sequence and nothing else preventing it from being hit? c) what is the status of your EMU0-1 JTAG pins are they both high or in tristate condition during OMAP boot? -> the wrong setting would prevent boot sequence from being executed d) is it on CS0? -> well OMAP boots out of CS0 e) Do you have an 8 bit or a 16 bit NAND? is your config file in x-loader, u-boot handling this correctly? -> accessing wrong width is not very helpful.. ;) f) Did you sign x-loader.bin.ift with signGP.c? Try this in x-loader directory: grep _start System.map|cut -d' ' -f1|xargs signGP x-load.bin -> x-loader loads up at the address we tell it to, few variants of x-loaders s...

Finally! After months of effort by many, mostly Dirk driving hard, we have omap3 support in: a) beagleboard b) overo c) evm d) pandora e) zoom1. This should ideally make omapzoom git based u-boo t redundant. Lets see if this happens in the upcoming days.. v2009.02 will have official support :).. Hip Hip Hooraah!!

[2013-03-06 update]: after a few years of letting things rot, I just managed to pick up my old binaries and gave it a dry run: https://github.com/nmenon/beagle-recover  has the original working binaries since the google groups link no longer work. NOTE: I HAVE NOT TRIED WITH ANY OF THE LATEST SOURCES. I do not have plans to do so in the future as well  - an quick try indicated things are broke :( [Original post] http://groups.google.com/group/beagleboard/web/beagle_recover.tar.bz2 has the recovery package ready to go for ubuntu 8.04 32bit OS: download this, run sudo ./recover_beagle.sh - as shown in the video... Steps summary: 1. first shutdown the board. 2. run 'sudo recover_beagle.sh /dev/ttyUSB0' in a terminal -> you need super user permissions(sudo permissions) to run this script. 3. Keep the pushbutton S1pressed while powering on the board -> there are two white push button switches, use the one closer to the edge of the board NOTE: if your nand is com...

After using a bunch of time getting firefox to upload from my ubuntu 8.10 box to here , I got an util which told me to use my code.google.com password instead of my google passwd.. Grrrr... anyway, couple of my sleep hours later, u-boot utils rev 0.2 "Jumpin' Monkey" is uploaded (the code name was made up as i typed ;))

for some time now, I have gone with the belief that the nand ecc imlementation such as this which I helped write good enough for nand devices, but Vimal Singh pointed me to these two articles: http://lists.infradead.org/pipermail/linux-mtd/2008-August/022611.html http://lists.infradead.org/pipermail/linux-mtd/2008-August/022613.html Essentially: If we do just old_ecc^new_ecc to detect/correct ecc errors - the logic handles the case of bit flip error at 63rd bit(as e.g.) faultily. I was completely unaware of this weakness of the algo.. thanks Vimal for pointing me here.. I have plans of setting up a bit of code to verify this (essentially hack up the current drivers by overriding the read path ;) ).. will post if I can proove(I suspect this would be the case) this is the case with gpmc..

Tony Lindgren, Linux OMAP maintainer announced that source.mvista.com linux omap copy would not be used anymore.. It has been more than three years since the discussion on hosting the kernel tree at mvista site .. Thank you mvista for hosting all our pulls to date.. from now on look here (actually it was there since 2006, though I will miss doing " linux omap git " on google).

Kinda got a few questions on how omap uboot utils works.. so here is my attempt to try and summarize what omap3 TRM says(for details TRM is the best place to go - yes, it is beautifully written ;) ): ARM is a useless unless we have some software to run on it, so OMAP has a special piece of ROM code which gets the initial control of things. Now, ROM code is capable of: a) booting off a memory device such as NOR, NAND, OneNAND, MMC etc.. kind of devices. b) booting off a peripheral such as UART, USB etc.. Before anyone asks, yep ROMCode is a software code within OMAP. And, yep, and yeah it's got all kind of drivers for devices it supports, and further yeah, it is a tiny optimized code and finally NO - you cant modify it since it is R ead O nly M emory. Now, in the world of OMAP s/w guys, (a) is called memory boot and (b) is called peripheral boot.. Now, how does ROM Code know what kind of device you have and which mode you want to boot from? This is called the SYSBOOT(again read th...