Re: Kmalloc returns which address

[Misbah khan <misbah_khan@engineer.com>]

hi Suresh

In linux kmelloc returns the pointer to virtual address not the physical
address, to return to the physical address there is different function
called ioremap 

for eg :-
char *buf_tx =kmalloc(100,GFP_KERNEL); // Tx buffer
char *buf_rx=kmalloc(100,GFP_KERNEL); // Rx buffer

ptr_tx=ioremap( buf_tx,100);
ptr_rx=ioremap(buf_rx,100);

To learn more about this go through Linux device driver by rubini 

I hope this will work for you 
regard 
Misbah

suresh suresh wrote:
> 
> Hi,
> 
> I am porting MPC8280 driver from vxWorks to Linux.
> 
> I want know the address return by kmalloc function? is it physical address
> or kernel virtual address.
> 
> For Tx and Rx, hardware uses buffers, so I have to allocate buffers and
> pass
> the pointer to hardware. Can I pass the pointer returned kmalloc?  or  I
> should convert it into physical address?
> 
> If it returns kernel virtual address, then how to convert into physical?
> 
> Thanks & Regards-
> Suresh
> 
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