Messages in this thread | | | Date | Fri, 11 Jul 2008 12:55:40 -0400 | From | David Brigada <> | Subject | Re: PCI-ISA Bridge not operating |
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Jordan Crouse wrote: > On 11/07/08 10:58 -0400, David Brigada wrote: >> Hi, >> >> I'm working with the MSM800XEV board from Digital-Logic. This board >> uses a Geode LX800 for a CPU and has the CS5536 companion board also >> installed. The board works with an IT8888G IC that provides a PCI/ISA >> bridge to a PC/104 bus that is externally provided. >> >> If I boot with FreeDOS, I can twiddle I/O ports, and the proper ISA >> signaling comes over the PC/104 bus. In Linux, the /IOW or /IOR line >> goes low as expected, but the address doesn't come over the bus. The >> DOS that I'm running doesn't seem to have any specific drivers for the >> chip, I'm guessing that the hardware should "just work" --- the IT8888G >> is designed to grab I/O requests in the ISA range off the PCI bus after >> a short delay if nothing else grabs them first. >> >> I have a feeling that it has something to do with the CS5536 companion >> chip, as it seems as though there is a driver for a PCI/ISA bridge on >> that chip, though I can't get much detail from AMD's datasheet on that >> functionality. I do know that on the MSM800XEV, any such functionality >> is wired to the IT8888G, not the CS5536. >> >> There are two kernel config options related to the PCI IDs of the parts >> of the device that handle the ISA bus, CONFIG_SCx200_ACB and >> CONFIG_CS5535_GPIO. I've tried disabling both, but it doesn't seem to help. >> >> In lspci, the CS5536 PCI/ISA bridge is shown, but not the IT8888G. >> >> Any ideas? > > ISA should indeed "just work". The only thing I'm wondering is if > the kernel is interfering (it shouldn't). I assume that since it works > in FreeDOS that there is no possibility that something on the PCI bus > is grabbing the cycles instead.
That's what I'm thinking --- that the CS5536 PCI/ISA bridge is claiming the cycles.
> How are you trying to access the device in Linux? Through a kernel module > or a user application running as root?
I've tried both. I have a kernel module that I wrote for the hardware. When I couldn't get that working, I tried looping some code that keeps touching the same I/O port that I'm using.
> Jordan >
Dave
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