----- Original Message ----- From: "Haavard Skinnemoen" haavard.skinnemoen@atmel.com To: "Martin Jarman" mjarman@cabledoc.co.uk Cc: u-boot@lists.denx.de Sent: Friday, October 10, 2008 12:43 PM Subject: Re: [U-Boot] Special memory test Question
Haavard Skinnemoen haavard.skinnemoen@atmel.com wrote:
to start at physical address zero and scribble over the entire physical address range of the processor until it eventually tries to access an invalid physical address and gets a bus error exception.
Actually, that's wrong. It won't scribble over anything since it only does reads. But it will access an invalid address and get a bus error exception eventually.
Nope, it's a user error. Try running this command instead:
loop.b 10400000 4
It's been running on my board for several minutes without crashing.
Btw, that command won't actually test the SDRAM since do_mem_loop() accesses cacheable memory. The first access will load the data into the dcache, and subsequent accesses will simply read it from the dcache and not cause any memory accesses.
What is this command supposed to test anyway? It's highly unlikely that it will find any SDRAM problems by simply reading an address without checking the result...
Haavard
Thank you for your replies, and I accept my 'user error' (head hung in shame) and can confirm the test appears to run correctly when called with the proper arguments. I note Wolfgang has answered your question about what the test is for.
best regards Martin Jarman