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From: | johan marx |
Subject: | Re: [Qemu-devel] spidev with omap3 running on qemu |
Date: | Sat, 3 Nov 2012 23:16:44 +0000 |
Hi Peter,
I had a closer look at the omap_spi. It is indeed not supposed to be a spi device (which is why it failed when treated like one). omap_spi makes the connection between the different spi registers and the spi.c. The way I see it is the following: omap_spi<->spi<->my_device I would therefore need to create my device and add it to the spi bus using spi_create_device (which does make sense since if there is nothing plugged in the spi bus, how can it communicate). I still have to look at the complete communication cycle, especially the receiving part. Regards, Johan > Date: Thu, 1 Nov 2012 16:22:31 +1000 > Subject: Re: [Qemu-devel] spidev with omap3 running on qemu > From: address@hidden > To: address@hidden > CC: address@hidden; address@hidden > > On Sat, Oct 27, 2012 at 7:24 PM, johan marx <address@hidden> wrote: > > Hi Peter, > > > > Thanks for the quick reply. I'm building with qemu-linaro > > Hi Johan, > > Sorry about the delay. > > Ive had a quick browse of this tree. The OMAP spi work there is ahead > of whats in mainline, but is still divergent from the the ssi based in > mainline that I have been working on. Should be a fairly mechanical > conversion to bring what PMM has done there over to SSI so there is > only one SPI bus implementation that can all the devices. That > something of a long term goal though. > > and launching qemu > > with "qemu-system-arm -M overo -m 512M -sd sd-image.img -clock unix -display > > none -serial stdio". > > For the spi device, I thought of using the omap_spi. I have been playing > > around last night with the spi_create_device function and I was able to have > > data going through. I used the tsc2005 device as the omap_spi device > > reported "Property '.channel' not found". > > Thats sounds like a bug in QEMU, probably in the Linaro tree SPI framework. > > > My final aim being to use qemu in a simulator, I would have to send the spi > > data to the PC linux side where the emulated hardware will be. I'm therefore > > not yet sure if it is not easier for me to develop my own spi device > > My guess is fixing the bugs you have encountered in the OMAP spi > controller is the path of least resistance. > > > directly instead of putting another layer on top of the omap_spi. > > Shouldn't be a layer onto of OMAP spi, rather a SPI device definition. > You should be able to do it in a self contained way without having to > worry about what spi controller (OMAP or otherwise) is driving your > device. > > Regards, > Peter > > > Regards, > > Johan > > > >> Date: Sat, 27 Oct 2012 11:06:07 +1000 > >> Subject: Re: [Qemu-devel] spidev with omap3 running on qemu > >> From: address@hidden > >> To: address@hidden > >> CC: address@hidden; address@hidden > > > >> > >> Hi Johan, > >> > >> On Sat, Oct 27, 2012 at 5:03 AM, johan marx <address@hidden> wrote: > >> > Hi, > >> > I have been trying to get the spi working on an emulated omap3 with qemu > >> > but > >> > so far I wasn't able to complete the cycle. I decided to use spidev in > >> > order > >> > to ease things. Here is what I currently did: > >> > > >> > >> What tree are you building QEMU from and what's your command line > >> invocation? > >> > >> > I changed the kernel so everything is working on the real overo board. > >> > So it > >> > is definitely a qemu problem. > >> > I put logging messages into the qemu code to see where I was stucked at: > >> > it > >> > is transmitting the spi messages but it gets stuck in the spi.c at the > >> > line > >> > if ((dev = bus->device[channel])). > >> > > >> > From that I think the bit I'm missing is the initialisation of the > >> > spidev > >> > device on the qemu side. I don't know if that has to be defined when > >> > launching qemu or if that has to be created in qemu source code (then > >> > where > >> > and how?). > >> > >> I know there is some OMAP SPI stuff in qemu but its not QOMified (the > >> frawework that lets you command line create devices) so you will have > >> to change source code if this is the case (assuming it is a device > >> creation problem). I recently did some work apadting hw/ssi.c for spi > >> and that is QOMified so may be worthwhile bringing you SPI devices > >> into that framework so you can command line create attached SPI > >> devices. If you can point me at a tree and the device models that are > >> your spi controller and devices (im guessing hw/omap_spi,c), then Ill > >> be able to give an idea of the effort involved. > >> > >> I may be able to help you contribute here, the biggest obstacle for me > >> however is testing. If you can provide tests that exercise the omap > >> SPI then I may be able to help with a OMAP SPI QOMification effort > >> (and you bug will hopefully come out in the wash). > >> > >> Regards, > >> Peter > >> > >> I haven't been able to find anything on that subject so I hope > >> > someone here can give me a hint. > >> > > >> > Thank you for your help, > >> > Johan |
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