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

Marc Zyngier
2016-02-10T15:09:44Z

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 <yvo@apm.com>
> Signed-off-by: Quan Nguyen <qnguyen@apm.com>
> ---
> 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 <tnhuynh@apm.com>.
> - * Y Vo <yvo@apm.com>.
> + * Author: Tin Huynh <tnhuynh@apm.com>.
> + * Y Vo <yvo@apm.com>.
> + * Quan Nguyen <qnguyen@apm.com>.
> *
> * 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...