HIGHMEM not working.

["Ramgopal Kota" <rkota@broadcom.com>]

 Hi,

I need help in running CPU with HIGH_MEM.
Below is the processor memory map .. It is base on MIPS64K Core.

0x0000_0000  -- 0x07FF_FFFF   -> RAM (Region 1)
0x0800_0000  -- 0x0FFF_FFFF   -> PCI BUS 1
0x2000_0000  -- 0x2FFF_FFFF   -> Flash Region
0x4000_0000  -- 0x47FF_FFFF   -> PCI BUS 2
0x8000_0000  -- 0xCFFF_FFFF   -> RAM (Region 2) the first 128MB is remapped into 0x8000_0000 .. 

The system has 256MB of PHYSICAL RAM .. 

I configured TLB's and added memory regions. The system boots up correctly ..
If I show cat /proc/meminfo it shows 256MB , it could allocate memory ( I verified with a simple program allocating the memory and writing some data)

There is a PCI MAC device on PCI BUS 2. The CPU is not able to perform DMA to/from device.
The MAC driver is allocating DMA buffers using the following code ..
{
    phy = virt_to_bus(high_memory);  << Resulting in 0xa000_0000; 
    virt = ioremap(pbase);    
}
The Linux configuration has no ZONE_DMA configuration ..

Few questions ..
  A) HIGH_MEMORY START Address is configured to 0x2000_0000 , is it correct value.
  B) Are there any data which can be dumped to know more information ?
  C) Do I need to enable MEMORY Discontinuous Config also ?  ( As I did not see a reason to enable this as memory in Region 2 is contiguous)
  D) I read in some articles on internet that if HIGH_MEM is used,PCI bounce buffers needs to be used ? Can some body point me how to set this up ?

Thanks & Regards,
Ramgopal Kota