Subject: [PATCH v5 1/3] gpio: xgene: Enable X-Gene standby GPIO as interrupt controller

From: [email-masked] (Marc Zyngier)
Date: Wed, 10 Feb 2016 15:09:44 +0000

Quan,

This is getting better. Some comments below.

On 29/01/16 04:28, Quan Nguyen wrote:
> Enable X-Gene standby GPIO controller as interrupt controller to provide
> its own resources. This avoids ambiguity where GIC interrupt resource is
> use as X-Gene standby GPIO interrupt resource in user driver.
> 
> Signed-off-by: Y Vo <[email-masked]>
> Signed-off-by: Quan Nguyen <[email-masked]>
> ---
>  drivers/gpio/gpio-xgene-sb.c | 275 ++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 243 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-xgene-sb.c b/drivers/gpio/gpio-xgene-sb.c
> index 282004d..026da90 100644
> --- a/drivers/gpio/gpio-xgene-sb.c
> +++ b/drivers/gpio/gpio-xgene-sb.c
> @@ -2,8 +2,9 @@
>   * AppliedMicro X-Gene SoC GPIO-Standby Driver
>   *
>   * Copyright (c) 2014, Applied Micro Circuits Corporation
> - * Author: 	Tin Huynh <[email-masked]>.
> - * 		Y Vo <[email-masked]>.
> + * Author:	Tin Huynh <[email-masked]>.
> + *		Y Vo <[email-masked]>.
> + *		Quan Nguyen <[email-masked]>.
>   *
>   * This program is free software; you can redistribute  it and/or modify it
>   * under  the terms of  the GNU General  Public License as published by the
> @@ -28,9 +29,14 @@
>  
>  #include "gpiolib.h"
>  
> -#define XGENE_MAX_GPIO_DS		22
> -#define XGENE_MAX_GPIO_DS_IRQ		6
> +/* Common property names */
> +#define XGENE_NIRQ_PROPERTY		"apm,nr-irqs"
> +#define XGENE_NGPIO_PROPERTY		"apm,nr-gpios"
> +#define XGENE_IRQ_START_PROPERTY	"apm,irq-start"
>  
> +#define XGENE_DFLT_MAX_NGPIO		22
> +#define XGENE_DFLT_MAX_NIRQ		6
> +#define XGENE_DFLT_IRQ_START_PIN	8
>  #define GPIO_MASK(x)			(1U << ((x) % 32))
>  
>  #define MPA_GPIO_INT_LVL		0x0290
> @@ -39,19 +45,32 @@
>  #define MPA_GPIO_IN_ADDR 		0x02a4
>  #define MPA_GPIO_SEL_LO 		0x0294
>  
> +#define GPIO_INT_LEVEL_H	0x000001
> +#define GPIO_INT_LEVEL_L	0x000000
> +
>  /**
>   * struct xgene_gpio_sb - GPIO-Standby private data structure.
>   * @gc:				memory-mapped GPIO controllers.
> - * @irq:			Mapping GPIO pins and interrupt number
> - * nirq:			Number of GPIO pins that supports interrupt
> + * @regs:			GPIO register base offset
> + * @irq_domain:			GPIO interrupt domain
> + * @irq_start:			GPIO pin that start support interrupt
> + * @nirq:			Number of GPIO pins that supports interrupt
> + * @parent_irq_base:		Start parent HWIRQ
>   */
>  struct xgene_gpio_sb {
>  	struct gpio_chip	gc;
> -	u32 *irq;
> -	u32 nirq;
> +	void __iomem		*regs;
> +	struct irq_domain	*irq_domain;
> +	u16			irq_start;
> +	u16			nirq;
> +	u16			parent_irq_base;
>  };
>  
> -static void xgene_gpio_set_bit(struct gpio_chip *gc, void __iomem *reg, u32 gpio, int val)
> +#define HWIRQ_TO_GPIO(priv, hwirq) ((hwirq) + (priv)->irq_start)
> +#define GPIO_TO_HWIRQ(priv, gpio) ((gpio) - (priv)->irq_start)
> +
> +static void xgene_gpio_set_bit(struct gpio_chip *gc,
> +				void __iomem *reg, u32 gpio, int val)
>  {
>  	u32 data;
>  
> @@ -63,23 +82,180 @@ static void xgene_gpio_set_bit(struct gpio_chip *gc, void __iomem *reg, u32 gpio
>  	gc->write_reg(reg, data);
>  }
>  
> -static int apm_gpio_sb_to_irq(struct gpio_chip *gc, u32 gpio)
> +static int xgene_gpio_sb_irq_set_type(struct irq_data *d, unsigned int type)
> +{
> +	struct xgene_gpio_sb *priv = irq_data_get_irq_chip_data(d);
> +	int gpio = HWIRQ_TO_GPIO(priv, d->hwirq);
> +	int lvl_type = GPIO_INT_LEVEL_H;
> +
> +	switch (type & IRQ_TYPE_SENSE_MASK) {
> +	case IRQ_TYPE_EDGE_RISING:
> +	case IRQ_TYPE_LEVEL_HIGH:
> +		lvl_type = GPIO_INT_LEVEL_H;
> +		break;
> +	case IRQ_TYPE_EDGE_FALLING:
> +	case IRQ_TYPE_LEVEL_LOW:
> +		lvl_type = GPIO_INT_LEVEL_L;
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	xgene_gpio_set_bit(&priv->gc, priv->regs + MPA_GPIO_SEL_LO,
> +			gpio * 2, 1);
> +	xgene_gpio_set_bit(&priv->gc, priv->regs + MPA_GPIO_INT_LVL,
> +			d->hwirq, lvl_type);
> +
> +	/* Propagate IRQ type setting to parent */
> +	if (type & IRQ_TYPE_EDGE_BOTH)
> +		return irq_chip_set_type_parent(d, IRQ_TYPE_EDGE_RISING);
> +	else
> +		return irq_chip_set_type_parent(d, IRQ_TYPE_LEVEL_HIGH);
> +}
> +
> +static void xgene_gpio_sb_irq_shutdown(struct irq_data *d)
> +{
> +	struct xgene_gpio_sb *priv = irq_data_get_irq_chip_data(d);
> +
> +	gpiochip_unlock_as_irq(&priv->gc, HWIRQ_TO_GPIO(priv, d->hwirq));
> +}
> +
> +static struct irq_chip xgene_gpio_sb_irq_chip = {
> +	.name           = "sbgpio",
> +	.irq_ack        = irq_chip_ack_parent,

There is no point calling irq_chip_ack_parent, as the GIC doesn't
implement an irq_ack method at all.

> +	.irq_eoi	= irq_chip_eoi_parent,
> +	.irq_mask       = irq_chip_mask_parent,
> +	.irq_unmask     = irq_chip_unmask_parent,
> +	.irq_set_type   = xgene_gpio_sb_irq_set_type,
> +	.irq_shutdown   = xgene_gpio_sb_irq_shutdown,
> +};
> +
> +static int xgene_gpio_sb_to_irq(struct gpio_chip *gc, u32 gpio)
>  {
>  	struct xgene_gpio_sb *priv = gpiochip_get_data(gc);
> +	struct irq_fwspec fwspec;
> +
> +	if ((gpio < priv->irq_start) ||
> +			(gpio > HWIRQ_TO_GPIO(priv, priv->nirq)))
> +		return -ENXIO;
> +
> +	if (gc->parent->of_node)
> +		fwspec.fwnode = of_node_to_fwnode(gc->parent->of_node);
> +	else
> +		fwspec.fwnode = gc->parent->fwnode;
> +	fwspec.param_count = 2;
> +	fwspec.param[0] = GPIO_TO_HWIRQ(priv, gpio);
> +	fwspec.param[1] = IRQ_TYPE_NONE;
> +	return irq_create_fwspec_mapping(&fwspec);
> +}
> +
> +static void xgene_gpio_sb_domain_activate(struct irq_domain *d,
> +		struct irq_data *irq_data)
> +{
> +	struct xgene_gpio_sb *priv = d->host_data;
> +	u32 gpio = HWIRQ_TO_GPIO(priv, irq_data->hwirq);
> +
> +	if (gpiochip_lock_as_irq(&priv->gc, gpio)) {
> +		dev_err(priv->gc.parent,
> +		"Unable to configure XGene GPIO standby pin %d as IRQ\n",
> +				gpio);
> +		return;
> +	}
> +
> +	xgene_gpio_set_bit(&priv->gc, priv->regs + MPA_GPIO_SEL_LO,
> +			gpio * 2, 1);
> +}
> +
> +static void xgene_gpio_sb_domain_deactivate(struct irq_domain *d,
> +		struct irq_data *irq_data)
> +{
> +	struct xgene_gpio_sb *priv = d->host_data;
> +	u32 gpio = HWIRQ_TO_GPIO(priv, irq_data->hwirq);
> +
> +	gpiochip_unlock_as_irq(&priv->gc, gpio);

Is it right to do the unlock both in irq_shutdown and domain_deactivate?
This seems a bit odd to me to have such an inbalance. My hunch is that
you should either implement irq_startup, do the locking there and drop
the unlock drop deactivate, or kill irq_shutdown.

Linus, what do you think?

> +	xgene_gpio_set_bit(&priv->gc, priv->regs + MPA_GPIO_SEL_LO,
> +			gpio * 2, 0);
> +}
>  
> -	if (priv->irq[gpio])
> -		return priv->irq[gpio];
> +static int xgene_gpio_sb_domain_translate(struct irq_domain *d,
> +		struct irq_fwspec *fwspec,
> +		unsigned long *hwirq,
> +		unsigned int *type)
> +{
> +	struct xgene_gpio_sb *priv = d->host_data;
> +
> +	if ((fwspec->param_count != 2) ||
> +		(fwspec->param[0] >= priv->nirq))
> +		return -EINVAL;
> +	*hwirq = fwspec->param[0];
> +	*type = fwspec->param[1];
> +	return 0;
> +}
> +
> +static int xgene_gpio_sb_domain_alloc(struct irq_domain *domain,
> +					unsigned int virq,
> +					unsigned int nr_irqs, void *data)
> +{
> +	struct irq_fwspec *fwspec = data;
> +	struct irq_fwspec parent_fwspec;
> +	struct xgene_gpio_sb *priv = domain->host_data;
> +	irq_hw_number_t hwirq;
> +	unsigned int i;
> +
> +	hwirq = fwspec->param[0];
> +	for (i = 0; i < nr_irqs; i++)
> +		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
> +				&xgene_gpio_sb_irq_chip, priv);
> +
> +	if (is_of_node(domain->parent->fwnode)) {
> +		parent_fwspec.fwnode = domain->parent->fwnode;
> +		parent_fwspec.param_count = 3;
> +		parent_fwspec.param[0] = 0;/* SPI */
> +		/* Skip SGIs and PPIs*/
> +		parent_fwspec.param[1] = hwirq + priv->parent_irq_base - 32;
> +		parent_fwspec.param[2] = fwspec->param[1];
> +	} else if (is_fwnode_irqchip(domain->parent->fwnode)) {
> +		parent_fwspec.fwnode = domain->parent->fwnode;

nit: You can move this out of the if/else, and always assign the fwnode.

> +		parent_fwspec.param_count = 2;
> +		parent_fwspec.param[0] = hwirq + priv->parent_irq_base;
> +		parent_fwspec.param[1] = fwspec->param[1];
> +	} else
> +		return -EINVAL;
>  
> -	return -ENXIO;
> +	return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs,
> +			&parent_fwspec);
>  }
>  
> +static void xgene_gpio_sb_domain_free(struct irq_domain *domain,
> +		unsigned int virq,
> +		unsigned int nr_irqs)
> +{
> +	struct irq_data *d;
> +	unsigned int i;
> +
> +	for (i = 0; i < nr_irqs; i++) {
> +		d = irq_domain_get_irq_data(domain, virq + i);
> +		irq_domain_reset_irq_data(d);
> +	}
> +}
> +
> +static const struct irq_domain_ops xgene_gpio_sb_domain_ops = {
> +	.translate      = xgene_gpio_sb_domain_translate,
> +	.alloc          = xgene_gpio_sb_domain_alloc,
> +	.free           = xgene_gpio_sb_domain_free,
> +	.activate	= xgene_gpio_sb_domain_activate,
> +	.deactivate	= xgene_gpio_sb_domain_deactivate,
> +};
> +
>  static int xgene_gpio_sb_probe(struct platform_device *pdev)
>  {
>  	struct xgene_gpio_sb *priv;
> -	u32 ret, i;
> -	u32 default_lines[] = {0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D};
> +	u32 ret;
>  	struct resource *res;
>  	void __iomem *regs;
> +	struct irq_domain *parent_domain = NULL;
> +	struct fwnode_handle *fwnode;
> +	u32 val32;
>  
>  	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
>  	if (!priv)
> @@ -90,6 +266,18 @@ static int xgene_gpio_sb_probe(struct platform_device *pdev)
>  	if (IS_ERR(regs))
>  		return PTR_ERR(regs);
>  
> +	priv->regs = regs;
> +
> +	ret = platform_get_irq(pdev, 0);
> +	if (ret > 0) {
> +		priv->parent_irq_base = irq_get_irq_data(ret)->hwirq;
> +		parent_domain = irq_get_irq_data(ret)->domain;
> +	}
> +	if (!parent_domain) {
> +		dev_err(&pdev->dev, "unable to obtain parent domain\n");
> +		return -ENODEV;
> +	}
> +
>  	ret = bgpio_init(&priv->gc, &pdev->dev, 4,
>  			regs + MPA_GPIO_IN_ADDR,
>  			regs + MPA_GPIO_OUT_ADDR, NULL,
> @@ -97,30 +285,51 @@ static int xgene_gpio_sb_probe(struct platform_device *pdev)
>          if (ret)
>                  return ret;
>  
> -	priv->gc.to_irq = apm_gpio_sb_to_irq;
> -	priv->gc.ngpio = XGENE_MAX_GPIO_DS;
> +	priv->gc.to_irq = xgene_gpio_sb_to_irq;
>  
> -	priv->nirq = XGENE_MAX_GPIO_DS_IRQ;
> +	/* Retrieve start irq pin, use default if property not found */
> +	priv->irq_start = XGENE_DFLT_IRQ_START_PIN;
> +	if (!device_property_read_u32(&pdev->dev,
> +					XGENE_IRQ_START_PROPERTY, &val32))

Is that for ACPI as well?

> +		priv->irq_start = val32;
>  
> -	priv->irq = devm_kzalloc(&pdev->dev, sizeof(u32) * XGENE_MAX_GPIO_DS,
> -				   GFP_KERNEL);
> -	if (!priv->irq)
> -		return -ENOMEM;
> +	/* Retrieve number irqs, use default if property not found */
> +	priv->nirq = XGENE_DFLT_MAX_NIRQ;
> +	if (!device_property_read_u32(&pdev->dev, XGENE_NIRQ_PROPERTY, &val32))
> +		priv->nirq = val32;
>  
> -	for (i = 0; i < priv->nirq; i++) {
> -		priv->irq[default_lines[i]] = platform_get_irq(pdev, i);
> -		xgene_gpio_set_bit(&priv->gc, regs + MPA_GPIO_SEL_LO,
> -                                   default_lines[i] * 2, 1);
> -		xgene_gpio_set_bit(&priv->gc, regs + MPA_GPIO_INT_LVL, i, 1);
> -	}
> +	/* Retrieve number gpio, use default if property not found */
> +	priv->gc.ngpio = XGENE_DFLT_MAX_NGPIO;
> +	if (!device_property_read_u32(&pdev->dev, XGENE_NGPIO_PROPERTY, &val32))
> +		priv->gc.ngpio = val32;
> +
> +	dev_info(&pdev->dev, "Support %d gpios, %d irqs start from pin %d\n",
> +			priv->gc.ngpio, priv->nirq, priv->irq_start);
>  
>  	platform_set_drvdata(pdev, priv);
>  
> -	ret = gpiochip_add_data(&priv->gc, priv);
> -	if (ret)
> -		dev_err(&pdev->dev, "failed to register X-Gene GPIO Standby driver\n");
> +	if (pdev->dev.of_node)
> +		fwnode = of_node_to_fwnode(pdev->dev.of_node);
>  	else
> -		dev_info(&pdev->dev, "X-Gene GPIO Standby driver registered\n");
> +		fwnode = pdev->dev.fwnode;
> +
> +	priv->irq_domain = irq_domain_create_hierarchy(parent_domain,
> +					0, priv->nirq, fwnode,
> +					&xgene_gpio_sb_domain_ops, priv);
> +	if (!priv->irq_domain)
> +		return -ENODEV;
> +
> +	priv->gc.irqdomain = priv->irq_domain;
> +
> +	ret = gpiochip_add_data(&priv->gc, priv);
> +	if (ret) {
> +		dev_err(&pdev->dev,
> +			"failed to register X-Gene GPIO Standby driver\n");
> +		irq_domain_remove(priv->irq_domain);
> +		return ret;
> +	}
> +
> +	dev_info(&pdev->dev, "X-Gene GPIO Standby driver registered\n");
>  
>  	if (priv->nirq > 0) {
>  		/* Register interrupt handlers for gpio signaled acpi events */
> @@ -138,6 +347,8 @@ static int xgene_gpio_sb_remove(struct platform_device *pdev)
>  		acpi_gpiochip_free_interrupts(&priv->gc);
>  	}
>  
> +	irq_domain_remove(priv->irq_domain);
> +
>  	gpiochip_remove(&priv->gc);
>  	return 0;
>  }
> 

Thanks,

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