[XenARM] Accessing IO memory from domain 0 (mini-OS)

[Rahul Balani <rahulb@xxxxxxxxxxx>]

Hi everyone,

We are working on the Xen-arm version released earlier by Samsung. We did minor modifications required to make it work on the i.MX21 based Cogent CSB735 platform. The platform is very much similar to the Freescale board that was used by Samsung (64 MB SDRAM mapped at 0xC0000000).

Now, we are trying to write device drivers in mini-os to access SPI bus from domain 0. Unfortunately, we are able to access IO memory corresponding to SPI peripheral (virtual address 0xE001700C) from within main.c:start_kernel() in mini-os ONLY uptil the call to local_irq_enable(). If we try to access I/O memory at any point after local_irq_enable(), it just kills the domain. Domain 1 (user domain) keeps running fine and we can see output on the console from threads running in that domain.

We have checked the Translation Table (page directory) entry corresponding to 0xE0000000 and it maps correctly to 0x10000000 (physical IO base) with seemingly correct flags (belongs to DOMAIN_IO, RW access for both privileged and user mode, section mapping). This copied as it is from the idle domain translation table. The same driver works fine from within Xen.

Any ideas on what kind of bug this could be, or where to look for it?

Thanks!
-Rahul.
_______________________________________________
Xen-arm mailing list
Xen-arm@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/mailman/listinfo/xen-arm