Re: [rpi bsp] configure fb section in mmu table and improvement for mailbox

[QIAO YANG]

On Jul 29, 2015, at 02:03 PM, Chris Johns <chrisj at rtems.org> wrote:

> On 29/07/2015 8:04 pm, Sebastian Huber wrote:
>>
>> A custom workspace initialization can be done via
>> bsp_work_area_initialize().
>>
>
> On the zynq the ethernet driver from Ric (SLAC) for the in tree
> (existing) IP stack there is:
>
> uint8_t* start;
> size_t size = 0x100000;
> uintptr_t boundary = (uintptr_t) 0;
> uintptr_t alignment = (uintptr_t) 0x100000;
> start = (uint8_t*) rtems_heap_allocate_aligned_with_boundary(size,
> alignment,
> boundary);
> arm_cp15_set_translation_table_entries(start,
> @start[size],
> ARMV7_MMU_DEVICE);

The arm_cp15_set_translation_table_entries function does help me to setup MMU entry at runtime.

What exactly means the "boundary"? For exemple, is it possible to allocate the memory with a given start address(memory from 0xC100000 to 0xD100000)? Because in my case, the start address and its length is given by GPU.

Actually, I've got everything worked without heap allocate and I've only setup the entry. Is it normal? I know little about how the memory managed and what happened here. 
>
>
> This creates an MMU entry at runtime for a 1M aligned block of memory
> that has the cache disabled.
>
> Chris
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