fail to disable MMU on ppc 8241
Hi, there,
I boot linux (2.6.3) on my ppc 8241 through vxworks bootloader. I'd got a port (on address 0x70020006) to constrol three LEDs, so I could know where the kernel going. But after the disable_mmu is called, I lost control to the LEDs, Any suggestion on this? As I know, vxworks use a one-to-one mapping MMU setup, I should must constrol the LEDs through the same address.
Thanks for any suggestion.
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Quoted 7 lines · llee
Hi, there,
I boot linux (2.6.3) on my ppc 8241 through vxworks bootloader. I'd got a port (on address0x70020006) to constrol three LEDs, so I could know where the kernel going. But after thedisable_mmuis called, I lost control to the LEDs, Any suggestion on this? As I know, vxworks use a one-to-one mapping MMU setup, I should must constrol the LEDs through the same address.
With mmu off, I suspect the 8241 acts as if the entire address space was cacheable, which is a BAD THING for IOs typically.
Ben.
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Quoted 13 lines · Benjamin Herrenschmidt
Quoted 9 lines · llee
Hi, there,
I boot linux (2.6.3) on my ppc 8241 through vxworks bootloader. I'd got a port (on address0x70020006) to constrol three LEDs, so I could know where the kernel going. But after thedisable_mmuis called, I lost control to the LEDs, Any suggestion on this? As I know, vxworks use a one-to-one mapping MMU setup, I should must constrol the LEDs through the same address.
Quoted 10 lines
With mmu off, I suspect the 8241 acts as if the entire address space was cacheable, which is a BAD THING for IOs typically.
Ben.
Thanks Ben, It works when I disable DATA CACHE!
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