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

-----Original Message-----
From: Timur Tabi [mailto:timur@freescale.com]
Sent: Thursday, February 08, 2007 1:03 AM
To: Kumar Gala
Cc: Li Yang-r58472; netdev@vger.kernel.org; linuxppc-dev@ozlabs.org
Subject: Re: [PATCH 1/4] ucc_geth: Change private immrbar_virt_to_phys

to generic

iopa

Kumar Gala wrote:

quoted

If its been mapped with ioremap() you know the physical address

already

quoted

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.

- Leo