Subject: [PATCH V5 2/4] DRIVERS: IRQCHIP: CROSSBAR: Add support for Crossbar IP

From: [email-masked] (Sricharan R)
Date: Thu, 16 Jan 2014 15:52:02 +0530

Hi Thomas,

On Tuesday 03 December 2013 03:57 PM, Sricharan R wrote:
> Some socs have a large number of interrupts requests to service
> the needs of its many peripherals and subsystems. All of the
> interrupt lines from the subsystems are not needed at the same
> time, so they have to be muxed to the irq-controller appropriately.
> In such places a interrupt controllers are preceded by an CROSSBAR
> that provides flexibility in muxing the device requests to the controller
> inputs.
> 
> This driver takes care a allocating a free irq and then configuring the
> crossbar IP as a part of the mpu's irqchip callbacks. crossbar_init should
> be called right before the irqchip_init, so that it is setup to handle the
> irqchip callbacks.
> 
> Cc: Thomas Gleixner <[email-masked]>
> Cc: Linus Walleij <[email-masked]>
> Cc: Santosh Shilimkar <[email-masked]>
> Cc: Russell King <[email-masked]>
> Cc: Tony Lindgren <[email-masked]>
> Cc: Rajendra Nayak <[email-masked]>
> Cc: Marc Zyngier <[email-masked]>
> Cc: Grant Likely <[email-masked]>
> Cc: Rob Herring <[email-masked]>
> Signed-off-by: Sricharan R <[email-masked]>
> Acked-by: Kumar Gala <[email-masked]> (for DT binding portion)
> Acked-by: Santosh Shilimkar <[email-masked]>
> Acked-by: Linus Walleij <[email-masked]>
> ---
>  [v5] Used the function of_property_read_u32_index instead of raw reading
>       from DT as per comments from Mark Rutland <[email-masked]>
> 
>  .../devicetree/bindings/arm/omap/crossbar.txt      |   27 +++
>  drivers/irqchip/Kconfig                            |    8 +
>  drivers/irqchip/Makefile                           |    1 +
>  drivers/irqchip/irq-crossbar.c                     |  208 ++++++++++++++++++++
>  include/linux/irqchip/irq-crossbar.h               |   11 ++
>  5 files changed, 255 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/arm/omap/crossbar.txt
>  create mode 100644 drivers/irqchip/irq-crossbar.c
>  create mode 100644 include/linux/irqchip/irq-crossbar.h
> 
> diff --git a/Documentation/devicetree/bindings/arm/omap/crossbar.txt b/Documentation/devicetree/bindings/arm/omap/crossbar.txt
> new file mode 100644
> index 0000000..fb88585
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/omap/crossbar.txt
> @@ -0,0 +1,27 @@
> +Some socs have a large number of interrupts requests to service
> +the needs of its many peripherals and subsystems. All of the
> +interrupt lines from the subsystems are not needed at the same
> +time, so they have to be muxed to the irq-controller appropriately.
> +In such places a interrupt controllers are preceded by an CROSSBAR
> +that provides flexibility in muxing the device requests to the controller
> +inputs.
> +
> +Required properties:
> +- compatible : Should be "ti,irq-crossbar"
> +- reg: Base address and the size of the crossbar registers.
> +- ti,max-irqs: Total number of irqs available at the interrupt controller.
> +- ti,reg-size: Size of a individual register in bytes. Every individual
> +	    register is assumed to be of same size. Valid sizes are 1, 2, 4.
> +- ti,irqs-reserved: List of the reserved irq lines that are not muxed using
> +		 crossbar. These interrupt lines are reserved in the soc,
> +		 so crossbar bar driver should not consider them as free
> +		 lines.
> +
> +Examples:
> +		crossbar_mpu: @4a020000 {
> +			compatible = "ti,irq-crossbar";
> +			reg = <0x4a002a48 0x130>;
> +			ti,max-irqs = <160>;
> +			ti,reg-size = <2>;
> +			ti,irqs-reserved = <0 1 2 3 5 6 131 132 139 140>;
> +		};
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index 3792a1a..2efcde6 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -61,3 +61,11 @@ config VERSATILE_FPGA_IRQ_NR
>         int
>         default 4
>         depends on VERSATILE_FPGA_IRQ
> +
> +config IRQ_CROSSBAR
> +	bool
> +	help
> +	  Support for a CROSSBAR ip that preceeds the main interrupt controller.
> +	  The primary irqchip invokes the crossbar's callback which inturn allocates
> +	  a free irq and configures the IP. Thus the peripheral interrupts are
> +	  routed to one of the free irqchip interrupt lines.
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index c60b901..2edead9 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -22,3 +22,4 @@ obj-$(CONFIG_RENESAS_IRQC)		+= irq-renesas-irqc.o
>  obj-$(CONFIG_VERSATILE_FPGA_IRQ)	+= irq-versatile-fpga.o
>  obj-$(CONFIG_ARCH_VT8500)		+= irq-vt8500.o
>  obj-$(CONFIG_TB10X_IRQC)		+= irq-tb10x.o
> +obj-$(CONFIG_IRQ_CROSSBAR)		+= irq-crossbar.o
> diff --git a/drivers/irqchip/irq-crossbar.c b/drivers/irqchip/irq-crossbar.c
> new file mode 100644
> index 0000000..ae605a3
> --- /dev/null
> +++ b/drivers/irqchip/irq-crossbar.c
> @@ -0,0 +1,208 @@
> +/*
> + *  drivers/irqchip/irq-crossbar.c
> + *
> + *  Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com
> + *  Author: Sricharan R <[email-masked]>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + */
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/slab.h>
> +#include <linux/irqchip/arm-gic.h>
> +
> +#define IRQ_FREE	-1
> +#define GIC_IRQ_START	32
> +
> +/*
> + * @int_max: maximum number of supported interrupts
> + * @irq_map: array of interrupts to crossbar number mapping
> + * @crossbar_base: crossbar base address
> + * @register_offsets: offsets for each irq number
> + */
> +struct crossbar_device {
> +	uint int_max;
> +	uint *irq_map;
> +	void __iomem *crossbar_base;
> +	int *register_offsets;
> +	void (*write) (int, int);
> +};
> +
> +static struct crossbar_device *cb;
> +
> +static inline void crossbar_writel(int irq_no, int cb_no)
> +{
> +	writel(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
> +}
> +
> +static inline void crossbar_writew(int irq_no, int cb_no)
> +{
> +	writew(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
> +}
> +
> +static inline void crossbar_writeb(int irq_no, int cb_no)
> +{
> +	writeb(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
> +}
> +
> +static inline int allocate_free_irq(int cb_no)
> +{
> +	int i;
> +
> +	for (i = 0; i < cb->int_max; i++) {
> +		if (cb->irq_map[i] == IRQ_FREE) {
> +			cb->irq_map[i] = cb_no;
> +			return i;
> +		}
> +	}
> +
> +	return -ENODEV;
> +}
> +
> +static int crossbar_domain_map(struct irq_domain *d, unsigned int irq,
> +			       irq_hw_number_t hw)
> +{
> +	cb->write(hw - GIC_IRQ_START, cb->irq_map[hw - GIC_IRQ_START]);
> +	return 0;
> +}
> +
> +static void crossbar_domain_unmap(struct irq_domain *d, unsigned int irq)
> +{
> +	irq_hw_number_t hw = irq_get_irq_data(irq)->hwirq;
> +
> +	if (hw > GIC_IRQ_START)
> +		cb->irq_map[hw - GIC_IRQ_START] = IRQ_FREE;
> +}
> +
> +static int crossbar_domain_xlate(struct irq_domain *d,
> +				 struct device_node *controller,
> +				 const u32 *intspec, unsigned int intsize,
> +				 unsigned long *out_hwirq,
> +				 unsigned int *out_type)
> +{
> +	unsigned long ret;
> +
> +	ret = allocate_free_irq(intspec[1]);
> +
> +	if (IS_ERR_VALUE(ret))
> +		return ret;
> +
> +	*out_hwirq = ret + GIC_IRQ_START;
> +	return 0;
> +}
> +
> +const struct irq_domain_ops routable_irq_domain_ops = {
> +	.map = crossbar_domain_map,
> +	.unmap = crossbar_domain_unmap,
> +	.xlate = crossbar_domain_xlate
> +};
> +
> +static int __init crossbar_of_init(struct device_node *node)
> +{
> +	int i, size, max, reserved = 0, entry;
> +	const __be32 *irqsr;
> +
> +	cb = kzalloc(sizeof(struct cb_device *), GFP_KERNEL);
> +
> +	if (!cb)
> +		return -ENOMEM;
> +
> +	cb->crossbar_base = of_iomap(node, 0);
> +	if (!cb->crossbar_base)
> +		goto err1;
> +
> +	of_property_read_u32(node, "ti,max-irqs", &max);
> +	cb->irq_map = kzalloc(max * sizeof(int), GFP_KERNEL);
> +	if (!cb->irq_map)
> +		goto err2;
> +
> +	cb->int_max = max;
> +
> +	for (i = 0; i < max; i++)
> +		cb->irq_map[i] = IRQ_FREE;
> +
> +	/* Get and mark reserved irqs */
> +	irqsr = of_get_property(node, "ti,irqs-reserved", &size);
> +	if (irqsr) {
> +		size /= sizeof(__be32);
> +
> +		for (i = 0; i < size; i++) {
> +			of_property_read_u32_index(node,
> +						   "ti,irqs-reserved",
> +						   i, &entry);
> +			if (entry > max) {
> +				pr_err("Invalid reserved entry\n");
> +				goto err3;
> +			}
> +			cb->irq_map[entry] = 0;
> +		}
> +	}
> +
> +	cb->register_offsets = kzalloc(max * sizeof(int), GFP_KERNEL);
> +	if (!cb->register_offsets)
> +		goto err3;
> +
> +	of_property_read_u32(node, "ti,reg-size", &size);
> +
> +	switch (size) {
> +	case 1:
> +		cb->write = crossbar_writeb;
> +		break;
> +	case 2:
> +		cb->write = crossbar_writew;
> +		break;
> +	case 4:
> +		cb->write = crossbar_writel;
> +		break;
> +	default:
> +		pr_err("Invalid reg-size property\n");
> +		goto err4;
> +		break;
> +	}
> +
> +	/*
> +	 * Register offsets are not linear because of the
> +	 * reserved irqs. so find and store the offsets once.
> +	 */
> +	for (i = 0; i < max; i++) {
> +		if (!cb->irq_map[i])
> +			continue;
> +
> +		cb->register_offsets[i] = reserved;
> +		reserved += size;
> +	}
> +
> +	register_routable_domain_ops(&routable_irq_domain_ops);
> +	return 0;
> +
> +err4:
> +	kfree(cb->register_offsets);
> +err3:
> +	kfree(cb->irq_map);
> +err2:
> +	iounmap(cb->crossbar_base);
> +err1:
> +	kfree(cb);
> +	return -ENOMEM;
> +}
> +
> +static const struct of_device_id crossbar_match[] __initconst = {
> +	{ .compatible = "ti,irq-crossbar" },
> +	{}
> +};
> +
> +int irqcrossbar_init(void)
> +{
> +	struct device_node *np;
> +	np = of_find_matching_node(NULL, crossbar_match);
> +	if (!np)
> +		return -ENODEV;
> +
> +	crossbar_of_init(np);
> +	return 0;
> +}
> diff --git a/include/linux/irqchip/irq-crossbar.h b/include/linux/irqchip/irq-crossbar.h
> new file mode 100644
> index 0000000..e5537b8
> --- /dev/null
> +++ b/include/linux/irqchip/irq-crossbar.h
> @@ -0,0 +1,11 @@
> +/*
> + *  drivers/irqchip/irq-crossbar.h
> + *
> + *  Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + */
> +int irqcrossbar_init(void);

I already have your reviewed-by tag for the first patch in this series.

Kevin was pointing out that irqchip maintainer tag is needed for this patch as well
to be merged. We are planning to take this series through arm-soc tree.

Can i please have your tag for this patch as well ?

Regards,
 Sricharan