Re: [PATCH V8 5/8] irqchip/gicv3-its: Refactor ITS DT init code to prepare for ACPI

[Tomasz Nowicki]

On 17.08.2016 17:58, Bjorn Helgaas wrote:
> On Wed, Aug 17, 2016 at 04:33:02PM +0800, Hanjun Guo wrote:
> > On 2016/8/11 18:06, Tomasz Nowicki wrote:
> > > In order to add ACPI support we need to isolate ACPI&DT common code and
> > > move DT logic to corresponding functions. To achieve this we are using
> > > firmware agnostic handle which can be unpacked to either DT or ACPI node.
> > >
> > > No functional changes other than a very minor one:
> > > 1. Terminate its_init call with -ENODEV for non-DT case which allows
> > > to remove hack from its-gic-v3.c.
> > > 2. Fix ITS base register address type (from 'unsigned long' to 'phys_addr_t'),
> > > as a bonus we get nice string formatting.
> > > 3. Since there is only one of ITS parent domain convert it to static global
> > > variable and drop the parameter from its_probe_one. Users can refer to it
> > > in more convenient way then.
> > [...]
> > > -static int __init its_probe(struct device_node *node,
> > > -			    struct irq_domain *parent)
> > > +static int __init its_probe_one(struct resource *res,
> > > +				struct fwnode_handle *handle, int numa_node)
> > >  {
> > > -	struct resource res;
> > >  	struct its_node *its;
> > >  	void __iomem *its_base;
> > >  	u32 val;
> > >  	u64 baser, tmp;
> > >  	int err;
> > >
> > > -	err = of_address_to_resource(node, 0, &res);
> > > -	if (err) {
> > > -		pr_warn("%s: no regs?\n", node->full_name);
> > > -		return -ENXIO;
> > > -	}
> > > -
> > > -	its_base = ioremap(res.start, resource_size(&res));
> > > +	its_base = ioremap(res->start, resource_size(res));
> > >  	if (!its_base) {
> > > -		pr_warn("%s: unable to map registers\n", node->full_name);
> > > +		pr_warn("ITS@%pa: Unable to map ITS registers\n", &res->start);
> > >  		return -ENOMEM;
> > >  	}
> > >
> > >  	val = readl_relaxed(its_base + GITS_PIDR2) & GIC_PIDR2_ARCH_MASK;
> > >  	if (val != 0x30 && val != 0x40) {
> > > -		pr_warn("%s: no ITS detected, giving up\n", node->full_name);
> > > +		pr_warn("ITS@%pa: No ITS detected, giving up\n", &res->start);
> > >  		err = -ENODEV;
> > >  		goto out_unmap;
> > >  	}
> > >
> > >  	err = its_force_quiescent(its_base);
> > >  	if (err) {
> > > -		pr_warn("%s: failed to quiesce, giving up\n",
> > > -			node->full_name);
> > > +		pr_warn("ITS@%pa: Failed to quiesce, giving up\n", &res->start);
> > >  		goto out_unmap;
> > >  	}
> > >
> > > -	pr_info("ITS: %s\n", node->full_name);
> > > +	pr_info("ITS@%pa\n", &res->start);
> >                 ^^
> >
> > When I was testing this patch set I found message printed as below:
> >
> > [    0.000000] ITS@0x00000000c6000000
>
> I think it'd be nicer to print the resource with %pR so we see the
> type and size in a way that matches other physical address usage.

The intention was to keep previous message layout but while we are here, 
%pR usage for this one pr_info seems nice to me.

> I don't know whether there is or should be a struct device associated
> with the ITS.  The its_probe_one() function looks similar to regular
> driver probe functions, so maybe there should be.
>
> If there were a struct device associated with the ITS, it'd be nicer
> to use dev_info() as well, of course.

Indeed dev_info() would be nice but there is no struct device for ITS.

Tomasz