This is the mail archive of the
ecos-discuss@sourceware.org
mailing list for the eCos project.
Re: problem enabling the caches on powerpc
Please keep your replies on the mailing list so that all may benefit.
Private support is available only with a support contract.
saurabh prakash wrote:
How do i test that burst acces to dram is working properly?
I have enabled the burst for the device by OR/BR registers.
You'll need to check your settings carefully and may need to enlist the
aid of a hardware expert with appropriate test equipment.
Verify what you have vs other known working designs - there are many
in the eCos source tree.
The board is working with MMU disabled.
There can be no cache/bursting with the MMU disabled, so this is expected.
thnx in advance,
saurabh
On 6/29/06, Gary Thomas <gary@mlbassoc.com> wrote:
saurabh prakash wrote:
> hi,
> i am working on mbx type board, with mpc860P, i had successfully
worked on
> similar board in the past. but i am having problems enabling the
> caches on the current
> board. As soon as the macro HAL_ICACHE_ENABLE() executes, the cpu
> gives an exception(SEI). To be precise the second "isync" gives an
> exception. I have modified the
> HAL_ICACHE_SIZE, HAL_ICACHE_LINE_SIZE, HAL_ICACHE_WAYS.... etc
according to
> the variant i am using but without any results. Can anybody suggest
> any solution.
>
>
> #define HAL_ICACHE_ENABLE()
> asm volatile ("isync;"
> "mtspr %0, %1;"
> "isync" <----- Executing this gives an exception
> : : "I" (CYGARC_REG_IC_CST), "r"
(CYGARC_REG_IC_CMD_CE))
The most likely cause is your hardware timings, in particular DRAM
setups. When you enable the cache(s), the CPU will start using burst
access to memory. If you've not set this up properly, exceptions will
occur.
Check your UPM tables.
--
------------------------------------------------------------
Gary Thomas | Consulting for the
MLB Associates | Embedded world
------------------------------------------------------------
--
Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss