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

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Date:   Tue, 25 Oct 2016 10:42:05 +0100
From:   Zubair Lutfullah Kakakhel <Zubair.Kakakhel@...tec.com>
To:     Marc Zyngier <marc.zyngier@....com>, <monstr@...str.eu>,
        <ralf@...ux-mips.org>, <tglx@...utronix.de>,
        <jason@...edaemon.net>, <alistair@...ple.id.au>,
        <mporter@...nel.crashing.org>
CC:     <soren.brinkmann@...inx.com>, <linux-kernel@...r.kernel.org>,
        <linux-mips@...ux-mips.org>, <michal.simek@...inx.com>,
        <linuxppc-dev@...ts.ozlabs.org>, <mpe@...erman.id.au>,
        <paulus@...ba.org>, <benh@...nel.crashing.org>
Subject: Re: [Patch v5 04/12] irqchip: xilinx: Add support for parent intc

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@...tec.com>
>>
>> ---
>> 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.
>