Date:	Wed, 4 Mar 2015 11:11:12 +0800
From:	Jisheng Zhang <jszhang@...vell.com>
To:	Alexey Brodkin <Alexey.Brodkin@...opsys.com>,
	Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Vineet Gupta" <Vineet.Gupta1@...opsys.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Jason Cooper <jason@...edaemon.net>
Subject: Re: [PATCH] irq-dw-apb-ictl: convert to platform device

Hi Alexsy,


+ Sebastian,

On Tue, 3 Mar 2015 06:56:59 -0800
Alexey Brodkin <Alexey.Brodkin@...opsys.com> wrote:

> This allows utilization of probe deferral if master interrupt controller
> was not yet probed.
> 
> In my case there's an DW APB GPIO configured as interrupt controller
> which is a master for DW APB INTC.
> 
> Interrupt controller sub-node of DW APB GPIO gets parsed only on DW APB
> GPIO real probe - before that slave interrupt controllers cannot resolve
> its master connection which lead to failures on probes of devices that
> use DW APB INTC as its interrupt controller.
> 
> Now when this driver is converted to a normal platform device it may use
> probe deferral and so all dependences between devices and their
> interrupt controllers are resolved automatically on boot.
> 
> Signed-off-by: Alexey Brodkin <abrodkin@...opsys.com>
> Cc: Vineet Gupta <vgupta@...opsys.com>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: Jason Cooper <jason@...edaemon.net>
> Cc: Jisheng Zhang <jszhang@...vell.com>
> ---
>  drivers/irqchip/irq-dw-apb-ictl.c | 112
> +++++++++++++++++++++++--------------- 1 file changed, 67 insertions(+), 45
> deletions(-)
> 
> diff --git a/drivers/irqchip/irq-dw-apb-ictl.c
> b/drivers/irqchip/irq-dw-apb-ictl.c index 53bb732..0b05c58 100644
> --- a/drivers/irqchip/irq-dw-apb-ictl.c
> +++ b/drivers/irqchip/irq-dw-apb-ictl.c
> @@ -11,13 +11,15 @@
>   * warranty of any kind, whether express or implied.
>   */
>  
> -#include <linux/io.h>

this headfile need to be kept for readl_relaxed/writel_relaxed

> -#include <linux/irq.h>
>  #include <linux/irqchip/chained_irq.h>
> -#include <linux/of_address.h>
>  #include <linux/of_irq.h>
> +#include <linux/of_platform.h>
> +#include <linux/module.h>

sort alphabetically

>  
> -#include "irqchip.h"
> +struct dw_apb_intl_priv {
> +	struct device		*dev;
> +	struct irq_domain	*irq_domain;
> +};
>  
>  #define APB_INT_ENABLE_L	0x00
>  #define APB_INT_ENABLE_H	0x04
> @@ -65,41 +67,38 @@ static void dw_apb_ictl_resume(struct irq_data *d)
>  #define dw_apb_ictl_resume	NULL
>  #endif /* CONFIG_PM */
>  
> -static int __init dw_apb_ictl_init(struct device_node *np,
> -				   struct device_node *parent)
> +static int dw_apb_ictl_probe(struct platform_device *pdev)
>  {
>  	unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
> -	struct resource r;
> -	struct irq_domain *domain;
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
>  	struct irq_chip_generic *gc;
> +	struct dw_apb_intl_priv *p;
> +	struct resource *res;
>  	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;
> -	}
> +	if (!np)
> +		return -ENODEV;
>  
> -	ret = of_address_to_resource(np, 0, &r);
> -	if (ret) {
> -		pr_err("%s: unable to get resource\n", np->full_name);
> -		return ret;
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0) {
> +		if (irq != -EPROBE_DEFER)
> +			dev_err(dev, "no irq resource %d\n", irq);
> +		return irq;
>  	}
>  
> -	if (!request_mem_region(r.start, resource_size(&r),
> np->full_name)) {
> -		pr_err("%s: unable to request mem region\n",
> np->full_name);
> +	p = devm_kzalloc(dev, sizeof(*p), GFP_KERNEL);
> +	if (!p)
>  		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;
> -	}
> +	p->dev = &pdev->dev;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	iobase = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(iobase))
> +		return PTR_ERR(iobase);
>  
>  	/*
>  	 * DW IP can be configured to allow 2-64 irqs. We can determine
> @@ -120,25 +119,27 @@ static int __init dw_apb_ictl_init(struct device_node
> *np, else
>  		nrirqs = fls(readl_relaxed(iobase + APB_INT_ENABLE_L));
>  
> -	domain = irq_domain_add_linear(np, nrirqs,
> -				       &irq_generic_chip_ops, NULL);
> -	if (!domain) {
> +	p->irq_domain = irq_domain_add_linear(np, nrirqs,
> +					      &irq_generic_chip_ops, NULL);
> +	if (!p->irq_domain) {
>  		pr_err("%s: unable to add irq domain\n", np->full_name);
> -		ret = -ENOMEM;
> -		goto err_unmap;
> +		return -ENOMEM;
>  	}
>  
> -	ret = irq_alloc_domain_generic_chips(domain, 32, (nrirqs > 32) ?
> 2 : 1,
> -					     np->name, handle_level_irq,
> clr, 0,
> +	ret = irq_alloc_domain_generic_chips(p->irq_domain, 32,
> +					     (nrirqs > 32) ? 2 : 1,
> np->name,
> +					     handle_level_irq, clr, 0,
>  					     IRQ_GC_MASK_CACHE_PER_TYPE |
>  					     IRQ_GC_INIT_MASK_CACHE);
>  	if (ret) {
> -		pr_err("%s: unable to alloc irq domain gc\n",
> np->full_name);
> -		goto err_unmap;
> +		dev_info(p->dev, "irq_alloc_domain_generic_chips
> failed\n");
> +		irq_domain_remove(p->irq_domain);
> +		p->irq_domain = NULL;
> +		return -ENOMEM;
>  	}
>  
> -	gc = irq_get_domain_generic_chip(domain, 0);
> -	gc->private = domain;
> +	gc = irq_get_domain_generic_chip(p->irq_domain, 0);
> +	gc->private = p->irq_domain;
>  	gc->reg_base = iobase;
>  
>  	gc->chip_types[0].regs.mask = APB_INT_MASK_L;
> @@ -159,12 +160,33 @@ static int __init dw_apb_ictl_init(struct device_node
> *np, 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;
> +static int dw_apb_ictl_remove(struct platform_device *pdev)
> +{
> +	struct dw_apb_intl_priv *p = platform_get_drvdata(pdev);
> +
> +	irq_domain_remove(p->irq_domain);
> +	return 0;
>  }
> -IRQCHIP_DECLARE(dw_apb_ictl,
> -		"snps,dw-apb-ictl", dw_apb_ictl_init);

So, the ictl won't be initialized in init_IRQ(), it will cause problems.

> +
> +static const struct of_device_id dw_apb_ictl_dt_ids[] = {
> +	{ .compatible = "snps,dw-apb-ictl", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, dw_apb_ictl_dt_ids);
> +
> +static struct platform_driver dw_apb_ictl_device_driver = {
> +	.probe		= dw_apb_ictl_probe,
> +	.remove		= dw_apb_ictl_remove,
> +	.driver		= {
> +		.name	= "synopsys_dw_apb_irq",
> +		.of_match_table	= of_match_ptr(dw_apb_ictl_dt_ids),
> +	}
> +};
> +
> +module_platform_driver(dw_apb_ictl_device_driver);

This is too late. If the ictl is needed during early boot, for example
on Marvell BG2Q DMP board, we still need to calibrate the delay loop, the
kernel will hang at "Calibrating delay loop..."

Thanks,
Jisheng
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