[PATCH 1/4] ucc_geth: Change private immrbar_virt_to_phys to generic iopa

[Kumar Gala]

On Feb 7, 2007, at 11:52 PM, Li Yang-r58472 wrote:

>> -----Original Message-----
>> From: Timur Tabi [mailto:timur at freescale.com]
>> Sent: Thursday, February 08, 2007 1:03 AM
>> To: Kumar Gala
>> Cc: Li Yang-r58472; netdev at vger.kernel.org; linuxppc-dev at ozlabs.org
>> Subject: Re: [PATCH 1/4] ucc_geth: Change private  
>> immrbar_virt_to_phys
> to generic
>> iopa
>>
>> Kumar Gala wrote:
>>
>>> If its been mapped with ioremap() you know the physical address
> already
>>> so why do you need iopa().
>>
>> That's what the original function immrbar_virt_to_phys() does.  We're
> trying to
>> get rid of it, because we thought is redundant with iopa().
>>
>> static inline unsigned long immrbar_virt_to_phys(volatile void *
> address)
>> {
>> 	if ( ((u32)address >= (u32)qe_immr) &&
>> 			((u32)address < ((u32)qe_immr + QE_IMMAP_SIZE))
> )
>> 		return (unsigned long)(address - (u32)qe_immr +
>> 				(u32)get_qe_base());
>> 	return (unsigned long)virt_to_phys(address);
>> }
>>
>> get_qe_base() does a search of the OF tree the first time it's  
>> called.
>>
>> Here's the code that calls immrbar_virt_to_phys():
>>
>> 	out_be32(&ugeth->p_send_q_mem_reg->sqqd[i].bd_ring_base,
>> 		 (u32) immrbar_virt_to_phys(ugeth->
>> 					    p_tx_bd_ring[i]));
>>
>>
>> Would it be better to replace this code with something like this:
>>
>> out_be32(&ugeth->p_send_q_mem_reg->sqqd[i].bd_ring_base,
>> 	get_qe_base() + ((void *) ugeth->p_tx_bd_ring[i] - (void *)
> qe_immr));
>
> No, we don't know if the BD ring is in MURAM or main memory as it is
> configurable.  iopa() is best choice to handle both case, IMHO.

Does MURAM behave differently than normal memory?

- k