Re: [Patch v5 04/12] irqchip: xilinx: Add support for parent intc

[Zubair Lutfullah Kakakhel]

Hi,

Thanks for the review.
Some comments in-line.

On 10/21/2016 10:48 AM, Marc Zyngier wrote:
> On 17/10/16 17:52, Zubair Lutfullah Kakakhel wrote:
> > The MIPS based xilfpga platform has the following IRQ structure
> >
> > Peripherals --> xilinx_intcontroller -> mips_cpu_int controller
> >
> > Add support for the driver to chain the irq handler
> >
> > Signed-off-by: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@xxxxxxxxxx>
> >
> > ---
> > V4 -> V5
> > Rebased to v4.9-rc1
> > Missing curly braces
> >
> > V3 -> V4
> > Clean up if/else when a parent is found
> > Pass irqchip structure to handler as data
> >
> > V2 -> V3
> > Reused existing parent node instead of finding again.
> > Cleanup up handler based on review
> >
> > V1 -> V2
> >
> > No change
> > ---
> >  drivers/irqchip/irq-xilinx-intc.c | 26 ++++++++++++++++++++++++--
> >  1 file changed, 24 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/irqchip/irq-xilinx-intc.c b/drivers/irqchip/irq-xilinx-intc.c
> > index 45e5154..dbf8b0c 100644
> > --- a/drivers/irqchip/irq-xilinx-intc.c
> > +++ b/drivers/irqchip/irq-xilinx-intc.c
> > @@ -15,6 +15,7 @@
> >  #include <linux/of_address.h>
> >  #include <linux/io.h>
> >  #include <linux/bug.h>
> > +#include <linux/of_irq.h>
> >
> >  /* No one else should require these constants, so define them locally here. */
> >  #define ISR 0x00			/* Interrupt Status Register */
> > @@ -154,11 +155,23 @@ static int xintc_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
> >  	.map = xintc_map,
> >  };
> >
> > +static void xil_intc_irq_handler(struct irq_desc *desc)
> > +{
> > +	u32 pending;
> > +
> > +	do {
> > +		pending = xintc_get_irq();
> > +		if (pending == -1U)
> > +			break;
> > +		generic_handle_irq(pending);
> > +	} while (true);
>
> This is missing the chained_irq_enter()/exit() calls, which will lead to
> races or lockups on the root irqchip.

I 'll fix it up in the next series.

> > +}
> > +
> >  static int __init xilinx_intc_of_init(struct device_node *intc,
> >  					     struct device_node *parent)
> >  {
> >  	u32 nr_irq;
> > -	int ret;
> > +	int ret, irq;
> >  	struct xintc_irq_chip *irqc;
> >
> >  	if (xintc_irqc) {
> > @@ -221,7 +234,16 @@ static int __init xilinx_intc_of_init(struct device_node *intc,
> >  		goto err_alloc;
> >  	}
> >
> > -	irq_set_default_host(root_domain);
> > +	if (parent) {
> > +		irq = irq_of_parse_and_map(intc, 0);
> > +		if (irq)
> > +			irq_set_chained_handler_and_data(irq,
> > +							 xil_intc_irq_handler,
> > +							 irqc);
> > +
>
> Shouldn't you return an error if irq is zero?

I'll add the following for the error case

	pr_err("%s: Parent exists but interrupts property not defined\n" , __func__);
	goto err_alloc;

Thanks
ZubairLK

> > +	} else {
> > +		irq_set_default_host(root_domain);
> > +	}
> >
> >  	return 0;
>
> Thanks,
>
> 	M.