linux-kernel - Re: [PATCH v7 01/12] irqchip: Add driver for Loongson I/O Local Interrupt Controller

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Date:   Wed, 25 Mar 2020 11:35:34 +0000
From:   Marc Zyngier <maz@...nel.org>
To:     Paul Cercueil <paul@...pouillou.net>
Cc:     Jiaxun Yang <jiaxun.yang@...goat.com>, linux-mips@...r.kernel.org,
        Huacai Chen <chenhc@...ote.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Jonathan Corbet <corbet@....net>,
        John Crispin <john@...ozen.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Jean Delvare <jdelvare@...e.com>,
        "David S. Miller" <davem@...emloft.net>,
        Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Andi Kleen <ak@...ux.intel.com>,
        "H. Nikolaus Schaller" <hns@...delico.com>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        Tiezhu Yang <yangtiezhu@...ngson.cn>,
        Yinglu Yang <yangyinglu@...ngson.cn>,
        Allison Randal <allison@...utok.net>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Paul Burton <paulburton@...nel.org>,
        Manuel Lauss <manuel.lauss@...il.com>,
        Serge Semin <fancer.lancer@...il.com>,
        Matt Redfearn <matt.redfearn@...s.com>,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-ide@...r.kernel.org
Subject: Re: [PATCH v7 01/12] irqchip: Add driver for Loongson I/O Local
 Interrupt Controller

On 2020-03-25 11:25, Paul Cercueil wrote:
> Hi Jiaxun,
> 
> 
> Le mer. 25 mars 2020 à 10:28, Jiaxun Yang <jiaxun.yang@...goat.com> a 
> écrit :
>> This controller appeared on Loongson family of chips as the primary
>> package interrupt source.
>> 
>> Signed-off-by: Jiaxun Yang <jiaxun.yang@...goat.com>
>> Co-developed-by: Huacai Chen <chenhc@...ote.com>
>> Signed-off-by: Huacai Chen <chenhc@...ote.com>
>> Reviewed-by: Marc Zyngier <maz@...nel.org>
>> ---
>> v4-v5:
>> 	Resolve suggestions from maz:
>> 		- Remove DT validation
>> 		- Simplify unnucessary functions & variables
>> ---
>>  drivers/irqchip/Kconfig                |   9 +
>>  drivers/irqchip/Makefile               |   1 +
>>  drivers/irqchip/irq-loongson-liointc.c | 261 
>> +++++++++++++++++++++++++
>>  3 files changed, 271 insertions(+)
>>  create mode 100644 drivers/irqchip/irq-loongson-liointc.c
>> 
>> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
>> index 6d397732138d..c609eaa319d2 100644
>> --- a/drivers/irqchip/Kconfig
>> +++ b/drivers/irqchip/Kconfig
>> @@ -513,4 +513,13 @@ config EXYNOS_IRQ_COMBINER
>>  	  Say yes here to add support for the IRQ combiner devices embedded
>>  	  in Samsung Exynos chips.
>> 
>> +config LOONGSON_LIOINTC
>> +	bool "Loongson Local I/O Interrupt Controller"
>> +	depends on MACH_LOONGSON64
>> +	default y
>> +	select IRQ_DOMAIN
>> +	select GENERIC_IRQ_CHIP
>> +	help
>> +	  Support for the Loongson Local I/O Interrupt Controller.
>> +
>>  endmenu
>> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
>> index eae0d78cbf22..5e7678efdfe6 100644
>> --- a/drivers/irqchip/Makefile
>> +++ b/drivers/irqchip/Makefile
>> @@ -105,3 +105,4 @@ obj-$(CONFIG_MADERA_IRQ)		+= irq-madera.o
>>  obj-$(CONFIG_LS1X_IRQ)			+= irq-ls1x.o
>>  obj-$(CONFIG_TI_SCI_INTR_IRQCHIP)	+= irq-ti-sci-intr.o
>>  obj-$(CONFIG_TI_SCI_INTA_IRQCHIP)	+= irq-ti-sci-inta.o
>> +obj-$(CONFIG_LOONGSON_LIOINTC)		+= irq-loongson-liointc.o
>> diff --git a/drivers/irqchip/irq-loongson-liointc.c 
>> b/drivers/irqchip/irq-loongson-liointc.c
>> new file mode 100644
>> index 000000000000..18de2c09ece4
>> --- /dev/null
>> +++ b/drivers/irqchip/irq-loongson-liointc.c
>> @@ -0,0 +1,261 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + *  Copyright (C) 2020, Jiaxun Yang <jiaxun.yang@...goat.com>
>> + *  Loongson Local IO Interrupt Controller support
>> + */
>> +
>> +#include <linux/errno.h>
>> +#include <linux/init.h>
>> +#include <linux/types.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/ioport.h>
>> +#include <linux/irqchip.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_irq.h>
>> +#include <linux/io.h>
>> +#include <linux/smp.h>
>> +#include <linux/irqchip/chained_irq.h>
>> +
>> +#include <boot_param.h>
>> +
>> +#define LIOINTC_CHIP_IRQ	32
>> +#define LIOINTC_NUM_PARENT 4
>> +
>> +#define LIOINTC_INTC_CHIP_START	0x20
>> +
>> +#define LIOINTC_REG_INTC_STATUS	(LIOINTC_INTC_CHIP_START + 0x20)
>> +#define LIOINTC_REG_INTC_EN_STATUS	(LIOINTC_INTC_CHIP_START + 0x04)
>> +#define LIOINTC_REG_INTC_ENABLE	(LIOINTC_INTC_CHIP_START + 0x08)
>> +#define LIOINTC_REG_INTC_DISABLE	(LIOINTC_INTC_CHIP_START + 0x0c)
>> +#define LIOINTC_REG_INTC_POL	(LIOINTC_INTC_CHIP_START + 0x10)
>> +#define LIOINTC_REG_INTC_EDGE	(LIOINTC_INTC_CHIP_START + 0x14)
>> +
>> +#define LIOINTC_SHIFT_INTx	4
>> +
>> +struct liointc_handler_data {
>> +	struct liointc_priv	*priv;
>> +	u32			parent_int_map;
>> +};
>> +
>> +struct liointc_priv {
>> +	struct irq_chip_generic		*gc;
>> +	struct liointc_handler_data	handler[LIOINTC_NUM_PARENT];
>> +	u8				map_cache[LIOINTC_CHIP_IRQ];
>> +};
>> +
>> +static void liointc_chained_handle_irq(struct irq_desc *desc)
>> +{
>> +	struct liointc_handler_data *handler = 
>> irq_desc_get_handler_data(desc);
>> +	struct irq_chip *chip = irq_desc_get_chip(desc);
>> +	struct irq_chip_generic *gc = handler->priv->gc;
>> +	u32 pending;
>> +
>> +	chained_irq_enter(chip, desc);
>> +
>> +	pending = readl(gc->reg_base + LIOINTC_REG_INTC_STATUS);
>> +
>> +	if (!pending)
>> +		spurious_interrupt();
>> +
>> +	while (pending) {
>> +		int bit = __ffs(pending);
>> +
>> +		generic_handle_irq(irq_find_mapping(gc->domain, bit));
>> +		pending &= ~BIT(bit);
>> +	}
> 
> Consider using the for_each_set_bit() macro from <linux/bitops.h>.
> See drivers/irqchip/irq-ingenic-tcu.c for instance.

which would require changing the pending type to be unsigned long.
Open-coding these if fine if it helps keeping the type system 
consistent.

         M.
-- 
Jazz is not dead. It just smells funny...