[PATCH V8] powerpc/fsl-pci: Unify pci/pcie initialization code

[Jia Hongtao-B38951]

> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Tuesday, August 21, 2012 6:04 AM
> To: Jia Hongtao-B38951
> Cc: linuxppc-dev at lists.ozlabs.org; galak at kernel.crashing.org; Li Yang-
> R58472; Bradley Hughes
> Subject: Re: [PATCH V8] powerpc/fsl-pci: Unify pci/pcie initialization
> code
> 
> On 08/20/2012 05:06 AM, Jia Hongtao wrote:
> > We unified the Freescale pci/pcie initialization by changing the
> > fsl_pci to a platform driver. In previous PCI code architecture the
> > initialization routine is called at board_setup_arch stage. Now the
> > initialization is done in probe function which is architectural
> > better. Also It's convenient for adding PM support for PCI controller
> in later patch.
> >
> > Now we registered pci controllers as platform devices. So we combine
> > two initialization code as one platform driver.
> >
> > Signed-off-by: Jia Hongtao <B38951 at freescale.com>
> > Signed-off-by: Li Yang <leoli at freescale.com>
> > Signed-off-by: Chunhe Lan <Chunhe.Lan at freescale.com>
> > ---
> > Changes for V8:
> > * Use previous primary determination. Based on the point that there are
> >   bugs on primary-less system.
> > * Add exceptional support on ge_imp3a in which the primary bus is not
> the
> >   first pci bus detected.
> 
> The exceptional thing about ge_imp3a is that it has no isa node, but
> we're not sure if it actually has isa or not.  We should not be relying
> on probe order in any case.  Device tree nodes are not ordered.

Yes... We don't know if ge_imp3a actually has isa and still no answer from
board owner. I just set primary as the board used to. At least we don't do
any harm.

> 
> Another interesting case is stxssa8555.dts, which has an i8259 node but
> no ISA node (are there any other instances of this?).  However, I can't
> tell if stx_gp3.c is the platform file that goes with this device tree,
> or if the platform code for stxssa8555 is out-of-tree (or some other file
> that I'm not seeing).

MPC8541_CDS and MPC8555_CDS also has i8259 but no ISA node. stx_gp3 seems go
with stxssa8555.dts but I'm not sure ether.

So you mean we have to look for i8259 too for determining primary.
Take device tree as evidence we can tell that real primary ether has isa node
or i8259 node. And if there is no isa we just arbitrarily designate one.

If this logic works well then ok.


> 
> > -void __devinit fsl_pci_init(void)
> > +void fsl_pci_assign_primary(void)
> >  {
> > -	int ret;
> >  	struct device_node *node;
> > -	struct pci_controller *hose;
> > -	dma_addr_t max = 0xffffffff;
> >
> >  	/* Callers can specify the primary bus using other means. */
> >  	if (!fsl_pci_primary) {
> 
> Since the whole point of this function is now to find the primary, just
> return if it's already set, instead of indenting the rest of the function.
> 
> > @@ -842,38 +839,60 @@ void __devinit fsl_pci_init(void)
> >  			node = fsl_pci_primary;
> >
> >  			if (of_match_node(pci_ids, node))
> > -				break;
> > +				return;
> >  		}
> > -	}
> >
> > -	node = NULL;
> > -	for_each_node_by_type(node, "pci") {
> > -		if (of_match_node(pci_ids, node)) {
> > +		node = of_find_node_by_type(NULL, "pci");
> > +		if (of_match_node(pci_ids, node))
> >
> 
> What if the node returned doesn't match?  If you're checking for this,
> handle the else-case (even if just with an error message).
> 
> -Scott