Message-ID: <526AE2F7.3040804@gmail.com>
Date:	Fri, 25 Oct 2013 22:30:31 +0100
From:	Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>
To:	Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>,
	Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>
CC:	Jason Cooper <jason@...edaemon.net>,
	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
	Arnd Bergmann <arnd@...db.de>,
	Thomas Gleixner <tglx@...utronix.de>,
	Mark Rutland <mark.rutland@....com>,
	Jisheng Zhang <jszhang@...vell.com>,
	devicetree@...r.kernel.org, linux-doc@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/8] irqchip: add DesignWare APB ICTL interrupt controller

On 10/17/2013 07:37 AM, Sebastian Hesselbarth wrote:
> This adds an irqchip driver and corresponding devicetree binding for the
> secondary interrupt controllers based on Synopsys DesignWare IP dw_apb_ictl.
>
> Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>
> Reviewed-by: Mark Rutland <mark.rutland@....com>
> Reviewed-by: Jisheng Zhang <jszhang@...vell.com>

Thomas (tglx),

can you please look at this and review it? IIRC, Olof already closed
the arm-soc merge window for v3.13, so there is plenty of time to get
this straight. Nevertheless, it would be great to have it in early in
v3.13.

Also, I prefer to have Mark look at the bindings again and maybe
update his remarks with the latest conclusions of KS.

Regards,
   Sebastian

> ---
> Changelog:
> v1->v2:
> - reword binding docu for reg property and add FIQ decoding note
>    (Suggested by Mark Rutland)
> - add cleanup on error path (Reported by Jisheng Zhang)
> RFCv1->RFCv2:
> - added copyright reference
>
> Cc: Jason Cooper <jason@...edaemon.net>
> Cc: Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
> Cc: Arnd Bergmann <arnd@...db.de>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: Mark Rutland <mark.rutland@....com>
> Cc: Jisheng Zhang <jszhang@...vell.com>
> Cc: devicetree@...r.kernel.org
> Cc: linux-doc@...r.kernel.org
> Cc: linux-arm-kernel@...ts.infradead.org
> Cc: linux-kernel@...r.kernel.org
> ---
>   .../interrupt-controller/snps,dw-apb-ictl.txt      |   32 +++++
>   drivers/irqchip/Kconfig                            |    4 +
>   drivers/irqchip/Makefile                           |    1 +
>   drivers/irqchip/irq-dw-apb-ictl.c                  |  150 ++++++++++++++++++++
>   4 files changed, 187 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/interrupt-controller/snps,dw-apb-ictl.txt
>   create mode 100644 drivers/irqchip/irq-dw-apb-ictl.c
>
> diff --git a/Documentation/devicetree/bindings/interrupt-controller/snps,dw-apb-ictl.txt b/Documentation/devicetree/bindings/interrupt-controller/snps,dw-apb-ictl.txt
> new file mode 100644
> index 0000000..4929117
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/interrupt-controller/snps,dw-apb-ictl.txt
> @@ -0,0 +1,32 @@
> +Synopsys DesignWare APB interrupt controller (dw_apb_ictl)
> +
> +Synopsys DesignWare provides interrupt controller IP for APB known as
> +dw_apb_ictl. The IP is used as secondary interrupt controller in some SoCs with
> +APB bus, e.g. Marvell Armada 1500.
> +
> +Required properties:
> +- compatible: shall be "snps,dw-apb-ictl"
> +- reg: physical base address of the controller and length of memory mapped
> +  region starting with ENABLE_LOW register
> +- interrupt-controller: identifies the node as an interrupt controller
> +- #interrupt-cells: number of cells to encode an interrupt-specifier, shall be 1
> +- interrupts: interrupt reference to primary interrupt controller
> +- interrupt-parent: (optional) reference specific primary interrupt controller
> +
> +The interrupt sources map to the corresponding bits in the interrupt
> +registers, i.e.
> +- 0 maps to bit 0 of low interrupts,
> +- 1 maps to bit 1 of low interrupts,
> +- 32 maps to bit 0 of high interrupts,
> +- 33 maps to bit 1 of high interrupts,
> +- (optional) fast interrupts start at 64.
> +
> +Example:
> +	aic: interrupt-controller@...0 {
> +		compatible = "snps,dw-apb-ictl";
> +		reg = <0x3000 0xc00>;
> +		interrupt-controller;
> +		#interrupt-cells = <1>;
> +		interrupt-parent = <&gic>;
> +		interrupts = <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>;
> +	};
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index 3792a1a..940638d 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -30,6 +30,10 @@ config ARM_VIC_NR
>   	  The maximum number of VICs available in the system, for
>   	  power management.
>
> +config DW_APB_ICTL
> +	bool
> +	select IRQ_DOMAIN
> +
>   config IMGPDC_IRQ
>   	bool
>   	select GENERIC_IRQ_CHIP
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index c60b901..6427323 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -6,6 +6,7 @@ obj-$(CONFIG_ARCH_MMP)			+= irq-mmp.o
>   obj-$(CONFIG_ARCH_MVEBU)		+= irq-armada-370-xp.o
>   obj-$(CONFIG_ARCH_MXS)			+= irq-mxs.o
>   obj-$(CONFIG_ARCH_S3C24XX)		+= irq-s3c24xx.o
> +obj-$(CONFIG_DW_APB_ICTL)		+= irq-dw-apb-ictl.o
>   obj-$(CONFIG_METAG)			+= irq-metag-ext.o
>   obj-$(CONFIG_METAG_PERFCOUNTER_IRQS)	+= irq-metag.o
>   obj-$(CONFIG_ARCH_MOXART)		+= irq-moxart.o
> diff --git a/drivers/irqchip/irq-dw-apb-ictl.c b/drivers/irqchip/irq-dw-apb-ictl.c
> new file mode 100644
> index 0000000..31e231e
> --- /dev/null
> +++ b/drivers/irqchip/irq-dw-apb-ictl.c
> @@ -0,0 +1,150 @@
> +/*
> + * Synopsys DW APB ICTL irqchip driver.
> + *
> + * Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>
> + *
> + * based on GPL'ed 2.6 kernel sources
> + *  (c) Marvell International Ltd.
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2.  This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +
> +#include <linux/io.h>
> +#include <linux/irq.h>
> +#include <linux/irqchip/chained_irq.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +
> +#include "irqchip.h"
> +
> +#define APB_INT_ENABLE_L	0x00
> +#define APB_INT_ENABLE_H	0x04
> +#define APB_INT_MASK_L		0x08
> +#define APB_INT_MASK_H		0x0c
> +#define APB_INT_FINALSTATUS_L	0x30
> +#define APB_INT_FINALSTATUS_H	0x34
> +
> +static void dw_apb_ictl_handler(unsigned int irq, struct irq_desc *desc)
> +{
> +	struct irq_chip *chip = irq_get_chip(irq);
> +	struct irq_chip_generic *gc = irq_get_handler_data(irq);
> +	struct irq_domain *d = gc->private;
> +	u32 stat;
> +	int n;
> +
> +	chained_irq_enter(chip, desc);
> +
> +	for (n = 0; n < gc->num_ct; n++) {
> +		stat = readl_relaxed(gc->reg_base +
> +				     APB_INT_FINALSTATUS_L + 4 * n);
> +		while (stat) {
> +			u32 hwirq = ffs(stat) - 1;
> +			generic_handle_irq(irq_find_mapping(d,
> +					    gc->irq_base + hwirq + 32 * n));
> +			stat &= ~(1 << hwirq);
> +		}
> +	}
> +
> +	chained_irq_exit(chip, desc);
> +}
> +
> +static int __init dw_apb_ictl_init(struct device_node *np,
> +				   struct device_node *parent)
> +{
> +	unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
> +	struct resource r;
> +	struct irq_domain *domain;
> +	struct irq_chip_generic *gc;
> +	void __iomem *iobase;
> +	int ret, nrirqs, irq;
> +	u32 reg;
> +
> +	/* Map the parent interrupt for the chained handler */
> +	irq = irq_of_parse_and_map(np, 0);
> +	if (irq <= 0) {
> +		pr_err("%s: unable to parse irq\n", np->full_name);
> +		return -EINVAL;
> +	}
> +
> +	ret = of_address_to_resource(np, 0, &r);
> +	if (ret) {
> +		pr_err("%s: unable to get resource\n", np->full_name);
> +		return ret;
> +	}
> +
> +	if (!request_mem_region(r.start, resource_size(&r), np->full_name)) {
> +		pr_err("%s: unable to request mem region\n", np->full_name);
> +		return -ENOMEM;
> +	}
> +
> +	iobase = ioremap(r.start, resource_size(&r));
> +	if (!iobase) {
> +		pr_err("%s: unable to map resource\n", np->full_name);
> +		ret = -ENOMEM;
> +		goto err_release;
> +	}
> +
> +	/*
> +	 * DW IP can be configured to allow 2-64 irqs. We can determine
> +	 * the number of irqs supported by writing into enable register
> +	 * and look for bits not set, as corresponding flip-flops will
> +	 * have been removed by sythesis tool.
> +	 */
> +
> +	/* mask and enable all interrupts */
> +	writel(~0, iobase + APB_INT_MASK_L);
> +	writel(~0, iobase + APB_INT_MASK_H);
> +	writel(~0, iobase + APB_INT_ENABLE_L);
> +	writel(~0, iobase + APB_INT_ENABLE_H);
> +
> +	reg = readl(iobase + APB_INT_ENABLE_H);
> +	if (reg)
> +		nrirqs = 32 + fls(reg);
> +	else
> +		nrirqs = fls(readl(iobase + APB_INT_ENABLE_L));
> +
> +	domain = irq_domain_add_linear(np, nrirqs,
> +				       &irq_generic_chip_ops, NULL);
> +	if (!domain) {
> +		pr_err("%s: unable to add irq domain\n", np->full_name);
> +		ret = -ENOMEM;
> +		goto err_unmap;
> +	}
> +
> +	ret = irq_alloc_domain_generic_chips(domain, 32, (nrirqs > 32) ? 2 : 1,
> +					     np->name, handle_level_irq, clr, 0,
> +					     IRQ_GC_INIT_MASK_CACHE);
> +	if (ret) {
> +		pr_err("%s: unable to alloc irq domain gc\n", np->full_name);
> +		goto err_unmap;
> +	}
> +
> +	gc = irq_get_domain_generic_chip(domain, 0);
> +	gc->private = domain;
> +	gc->reg_base = iobase;
> +
> +	gc->chip_types[0].regs.mask = APB_INT_MASK_L;
> +	gc->chip_types[0].chip.irq_mask = irq_gc_mask_set_bit;
> +	gc->chip_types[0].chip.irq_unmask = irq_gc_mask_clr_bit;
> +
> +	if (nrirqs > 32) {
> +		gc->chip_types[1].regs.mask = APB_INT_MASK_H;
> +		gc->chip_types[1].chip.irq_mask = irq_gc_mask_set_bit;
> +		gc->chip_types[1].chip.irq_unmask = irq_gc_mask_clr_bit;
> +	}
> +
> +	irq_set_handler_data(irq, gc);
> +	irq_set_chained_handler(irq, dw_apb_ictl_handler);
> +
> +	return 0;
> +
> +err_unmap:
> +	iounmap(iobase);
> +err_release:
> +	release_mem_region(r.start, resource_size(&r));
> +	return ret;
> +}
> +IRQCHIP_DECLARE(dw_apb_ictl,
> +		"snps,dw-apb-ictl", dw_apb_ictl_init);
>

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