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

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On Wed, Feb 10, 2016 at 10:09 PM, Marc Zyngier <marc.zyngier@xxxxxxx> wrote:
> 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@xxxxxxx>
>> Signed-off-by: Quan Nguyen <qnguyen@xxxxxxx>
>> ---
>>  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@xxxxxxx>.
>> - *           Y Vo <yvo@xxxxxxx>.
>> + * Author:   Tin Huynh <tnhuynh@xxxxxxx>.
>> + *           Y Vo <yvo@xxxxxxx>.
>> + *           Quan Nguyen <qnguyen@xxxxxxx>.
>>   *
>>   * 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.
>

Thanks Marc, let me remove it.

>> +     .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?
>

I refer to kill irq_shutdown.

>> +     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.

Thanks Marc, let me change it.

>
>> +             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?
>

Yes, Marc.

>> +             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...
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