Re: [PATCH v8 2/4] irqchip: add platform device driver for mbigen device

[Marc Zyngier]

On 06/11/15 08:28, MaJun wrote:
> From: Ma Jun <majun258@xxxxxxxxxx>
> 
> Mbigen means Message Based Interrupt Generator(MBIGEN).
> 
> Its a kind of interrupt controller that collects
> the interrupts from external devices and generate msi interrupt.
> Mbigen is applied to reduce the number of wire connected interrupts.
> 
> As the peripherals increasing, the interrupts lines needed is
> increasing much, especially on the Arm64 server SOC.
> 
> Therefore, the interrupt pin in GIC is not enough to cover so
> many peripherals.
> 
> Mbigen is designed to fix this problem.
> 
> Mbigen chip locates in ITS or outside of ITS.
> 
> Mbigen chip hardware structure shows as below:
> 
> 		mbigen chip
> |---------------------|-------------------|
> mgn_node0	  mgn_node1		mgn_node2
>  |		 |-------|		|-------|------|
> dev1		dev1    dev2		dev1   dev3   dev4
> 
> Each mbigen chip contains several mbigen nodes.
> 
> External devices can connect to mbigen node through wire connecting way.
> 
> Because a mbigen node only can support 128 interrupt maximum, depends
> on the interrupt lines number of devices, a device can connects to one
> more mbigen nodes.
> 
> Also, several different devices can connect to a same mbigen node.
> 
> When devices triggered interrupt,mbigen chip detects and collects
> the interrupts and generates the MBI interrupts by writing the ITS
> Translator register.
> 
> To simplify mbigen driver,I used a new conception--mbigen device.
> Each mbigen device is initialized as a platform device.
> 
> Mbigen device presents the parts(register, pin definition etc.) in
> mbigen chip corresponding to a peripheral device.
> 
> So from software view, the structure likes below
> 
> 	            mbigen chip
>      |---------------------|-----------------|
> mbigen device1       mbigen device2  mbigen device3
>       |                   |                |
>      dev1                dev2             dev3
> 
> Signed-off-by: Ma Jun <majun258@xxxxxxxxxx>
> ---
>  drivers/irqchip/Kconfig      |    8 ++++
>  drivers/irqchip/Makefile     |    1 +
>  drivers/irqchip/irq-mbigen.c |   73 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 82 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/irqchip/irq-mbigen.c
> 
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index 4d7294e..b205e15 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -27,6 +27,14 @@ config ARM_GIC_V3_ITS
>  	bool
>  	select PCI_MSI_IRQ_DOMAIN
>  
> +config HISILICON_IRQ_MBIGEN
> +	bool "Support mbigen interrupt controller"
> +	default n
> +	depends on ARM_GIC_V3 && ARM_GIC_V3_ITS && GENERIC_MSI_IRQ_DOMAIN
> +	help
> +	 Enable the mbigen interrupt controller used on
> +	 Hisilicon platform.
> +
>  config ARM_NVIC
>  	bool
>  	select IRQ_DOMAIN
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index 177f78f..cd76b11 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -24,6 +24,7 @@ obj-$(CONFIG_ARM_GIC)			+= irq-gic.o irq-gic-common.o
>  obj-$(CONFIG_ARM_GIC_V2M)		+= irq-gic-v2m.o
>  obj-$(CONFIG_ARM_GIC_V3)		+= irq-gic-v3.o irq-gic-common.o
>  obj-$(CONFIG_ARM_GIC_V3_ITS)		+= irq-gic-v3-its.o irq-gic-v3-its-pci-msi.o irq-gic-v3-its-platform-msi.o
> +obj-$(CONFIG_HISILICON_IRQ_MBIGEN)	+= irq-mbigen.o
>  obj-$(CONFIG_ARM_NVIC)			+= irq-nvic.o
>  obj-$(CONFIG_ARM_VIC)			+= irq-vic.o
>  obj-$(CONFIG_ATMEL_AIC_IRQ)		+= irq-atmel-aic-common.o irq-atmel-aic.o
> diff --git a/drivers/irqchip/irq-mbigen.c b/drivers/irqchip/irq-mbigen.c
> new file mode 100644
> index 0000000..25e4000
> --- /dev/null
> +++ b/drivers/irqchip/irq-mbigen.c
> @@ -0,0 +1,73 @@
> +/*
> + * Copyright (C) 2015 Hisilicon Limited, All Rights Reserved.
> + * Author: Jun Ma <majun258@xxxxxxxxxx>
> + * Author: Yun Wu <wuyun.wu@xxxxxxxxxx>
> + *
> + * 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.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +/**
> + * struct mbigen_device - holds the information of mbigen device.
> + *
> + * @pdev:		pointer to the platform device structure of mbigen chip.
> + * @base:		mapped address of this mbigen chip.
> + */
> +struct mbigen_device {
> +	struct platform_device	*pdev;
> +	void __iomem		*base;
> +};
> +
> +static int mbigen_device_probe(struct platform_device *pdev)
> +{
> +	struct mbigen_device *mgn_chip;
> +
> +	mgn_chip = devm_kzalloc(&pdev->dev, sizeof(*mgn_chip), GFP_KERNEL);
> +	if (!mgn_chip)
> +		return -ENOMEM;
> +
> +	mgn_chip->pdev = pdev;
> +	mgn_chip->base = of_iomap(pdev->dev.of_node, 0);
> +

If you're going to use the devm_* stuff for your allocations, you might
as well use devm_ioremap_resource as a matter of consistency. And
checking the return value is not superfluous.

> +	platform_set_drvdata(pdev, mgn_chip);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id mbigen_of_match[] = {
> +	{ .compatible = "hisilicon,mbigen-v2" },
> +	{ /* END */ }
> +};
> +MODULE_DEVICE_TABLE(of, mbigen_of_match);
> +
> +static struct platform_driver mbigen_platform_driver = {
> +	.driver = {
> +		.name		= "Hisilicon MBIGEN-V2",
> +		.owner		= THIS_MODULE,
> +		.of_match_table	= mbigen_of_match,
> +	},
> +	.probe			= mbigen_device_probe,
> +};
> +
> +module_platform_driver(mbigen_platform_driver);
> +
> +MODULE_AUTHOR("Jun Ma <majun258@xxxxxxxxxx>");
> +MODULE_AUTHOR("Yun Wu <wuyun.wu@xxxxxxxxxx>");
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Hisilicon MBI Generator driver");
> 

Thanks,

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