Hi Jonathan,
Thank you very much for the tip.
I did overwrite the translation table with an additional entry and can now
successfully access the device.
Cheers,
Jan
From: Jonathan Brandmeyer <[email protected]>
Sent: Wednesday, November 18, 2020 5:01 PM
To: Sommer, Jan <[email protected]>
Cc: RTEMS <[email protected]>
Subject: Re: Acessing PL devices of Xilinx Zedboard
On Wed, Nov 18, 2020 at 8:37 AM <[email protected]<mailto:[email protected]>>
wrote:
Hello,
We try to use the xilinx_zynq_zedboard BSP with some devices synthesized to the
PL, e.g. a Xilinx NS16550 Uart.
If I try to access any of the AXI registers, I get a fatal error with a vector
number 0x04 (undefined instruction).
Accessing the same register address from within a Xilinx standalone hello-world
program works as expected.
Could it be that during the RTEMS startup some of the system initialization is
reset so that accessing the PL devices fails?
The default memory map does not provide access to any of the PL address range.
You'll have to override the weak symbol zynq_setup_mmu_and_cache to provide
your own memory map. The MMU code only supports 1 MB superpages at this time.
Caveat: My information could be a little out of date. We're still running on a
pre-release version of RTEMS 5.0. But hopefully this points you in the right
direction. In particular, I know that some work has been done to support 4kB
pages, but I don't know if the entry point
arm_cp15_start_setup_translation_table_and_enable_mmu_and_cache currently uses
that support or not.
--
Jonathan Brandmeyer
PlanetiQ
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