Need help Please:IOMEM memory allocation

[Bizhan Gholikhamseh (bgholikh)]

Hi All,
I am trying to develop a SPI driver for MPC8541. 
I need to allocate memory buffers within kernel that their physical
address is
on 64 byte boundary and initialize the transmit and receive buffer
descriptors with the
their physical locations. Since I am not sure how to do this within the
kernel here is how I am doing it:
 
 unsigned long mem_addr_rx = __get_free_page(GFP_KERNEL);  //receive
buffer
 unsigned long mem_addr_tx = __get_free_page(GFP_KERNEL); //transmit
buffer
.....
rx_buffer_addr = __pa(mem_addr_rx);
tx_buffer_addr=__pa(mem_addr_tx);
 
My assumption is by allocating a page, I am guaranteed that I will have
64 byte boundary condition.
Is this correct?
 
I have also told, the SPI does not have snoop bit, so I need to allocate
buffers from iomem, I have
no idea how to do this.
 
Please help,
Many thanks in advance,
Regards,
Bizhan
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