Re: [PATCH 1/4] regmap: irq: Fix lost interrupts by introducing handle_reread

[Lee Jones <lee.jones@linaro.org>]

On Wed, 22 Mar 2017, Tony Lindgren wrote:

> At least Motorola CPCAP PMIC needs it's device interrupts re-read
> until there are no more interrupts. Otherwise the PMIC interrupt to
> the SoC will eventually stop toggling. This seems to be a bug in the
> CPCAP PMIC where it can stop driving the GPIO interrupt to the SoC
> with pending CPCAP interrupts.
> 
> Let's allow handling issues like this by introducing a flag for
> handle_reread and by splitting regmap_irq_thread() into two separate
> functions for regmap_read_irq_status() and regmap_irq_handle_pending().
> 
> Cc: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
> Cc: Lee Jones <lee.jones@linaro.org>
> Cc: Marcel Partap <mpartap@gmx.net>
> Cc: Michael Scott <michael.scott@linaro.org>
> Tested-by: Sebastian Reichel <sre@kernel.org>
> Signed-off-by: Tony Lindgren <tony@atomide.com>
> ---
>  drivers/base/regmap/regmap-irq.c | 77 +++++++++++++++++++++++++++-------------
>  include/linux/regmap.h           |  2 ++
>  2 files changed, 55 insertions(+), 24 deletions(-)

Looks like this is required for the MFD patches.

I'm removing them for now.

> diff --git a/drivers/base/regmap/regmap-irq.c b/drivers/base/regmap/regmap-irq.c
> --- a/drivers/base/regmap/regmap-irq.c
> +++ b/drivers/base/regmap/regmap-irq.c
> @@ -259,27 +259,11 @@ static const struct irq_chip regmap_irq_chip = {
>  	.irq_set_wake		= regmap_irq_set_wake,
>  };
>  
> -static irqreturn_t regmap_irq_thread(int irq, void *d)
> +static int regmap_read_irq_status(struct regmap_irq_chip_data *data)
>  {
> -	struct regmap_irq_chip_data *data = d;
>  	const struct regmap_irq_chip *chip = data->chip;
>  	struct regmap *map = data->map;
>  	int ret, i;
> -	bool handled = false;
> -	u32 reg;
> -
> -	if (chip->handle_pre_irq)
> -		chip->handle_pre_irq(chip->irq_drv_data);
> -
> -	if (chip->runtime_pm) {
> -		ret = pm_runtime_get_sync(map->dev);
> -		if (ret < 0) {
> -			dev_err(map->dev, "IRQ thread failed to resume: %d\n",
> -				ret);
> -			pm_runtime_put(map->dev);
> -			goto exit;
> -		}
> -	}
>  
>  	/*
>  	 * Read in the statuses, using a single bulk read if possible
> @@ -299,7 +283,7 @@ static irqreturn_t regmap_irq_thread(int irq, void *d)
>  		if (ret != 0) {
>  			dev_err(map->dev, "Failed to read IRQ status: %d\n",
>  				ret);
> -			goto exit;
> +			return ret;
>  		}
>  
>  		for (i = 0; i < data->chip->num_regs; i++) {
> @@ -315,7 +299,7 @@ static irqreturn_t regmap_irq_thread(int irq, void *d)
>  				break;
>  			default:
>  				BUG();
> -				goto exit;
> +				return ret;
>  			}
>  		}
>  
> @@ -330,13 +314,21 @@ static irqreturn_t regmap_irq_thread(int irq, void *d)
>  				dev_err(map->dev,
>  					"Failed to read IRQ status: %d\n",
>  					ret);
> -				if (chip->runtime_pm)
> -					pm_runtime_put(map->dev);
> -				goto exit;
> +				return ret;
>  			}
>  		}
>  	}
>  
> +	return 0;
> +}
> +
> +static int regmap_irq_handle_pending(struct regmap_irq_chip_data *data)
> +{
> +	const struct regmap_irq_chip *chip = data->chip;
> +	struct regmap *map = data->map;
> +	int ret, i, handled = 0;
> +	u32 reg;
> +
>  	/*
>  	 * Ignore masked IRQs and ack if we need to; we ack early so
>  	 * there is no race between handling and acknowleding the
> @@ -361,14 +353,51 @@ static irqreturn_t regmap_irq_thread(int irq, void *d)
>  		if (data->status_buf[chip->irqs[i].reg_offset /
>  				     map->reg_stride] & chip->irqs[i].mask) {
>  			handle_nested_irq(irq_find_mapping(data->domain, i));
> -			handled = true;
> +			handled++;
> +		}
> +	}
> +
> +	return handled;
> +}
> +
> +static irqreturn_t regmap_irq_thread(int irq, void *d)
> +{
> +	struct regmap_irq_chip_data *data = d;
> +	const struct regmap_irq_chip *chip = data->chip;
> +	struct regmap *map = data->map;
> +	int ret, handled = 0;
> +
> +	if (chip->handle_pre_irq)
> +		chip->handle_pre_irq(chip->irq_drv_data);
> +
> +	if (chip->runtime_pm) {
> +		ret = pm_runtime_get_sync(map->dev);
> +		if (ret < 0) {
> +			dev_err(map->dev, "IRQ thread failed to resume: %d\n",
> +				ret);
> +			goto out_runtime_put;
>  		}
>  	}
>  
> +	do {
> +		ret = regmap_read_irq_status(data);
> +		if (ret)
> +			goto out_runtime_put;
> +
> +		ret = regmap_irq_handle_pending(data);
> +		if (ret < 0)
> +			goto out_runtime_put;
> +
> +		if (!ret)
> +			break;
> +
> +		handled += ret;
> +	} while (chip->handle_reread);
> +
> +out_runtime_put:
>  	if (chip->runtime_pm)
>  		pm_runtime_put(map->dev);
>  
> -exit:
>  	if (chip->handle_post_irq)
>  		chip->handle_post_irq(chip->irq_drv_data);
>  
> diff --git a/include/linux/regmap.h b/include/linux/regmap.h
> --- a/include/linux/regmap.h
> +++ b/include/linux/regmap.h
> @@ -897,6 +897,7 @@ struct regmap_irq {
>   * @ack_invert:  Inverted ack register: cleared bits for ack.
>   * @wake_invert: Inverted wake register: cleared bits are wake enabled.
>   * @type_invert: Invert the type flags.
> + * @handle_reread: Read interrupt status until no more interrupts are seen.
>   * @runtime_pm:  Hold a runtime PM lock on the device when accessing it.
>   *
>   * @num_regs:    Number of registers in each control bank.
> @@ -934,6 +935,7 @@ struct regmap_irq_chip {
>  	bool wake_invert:1;
>  	bool runtime_pm:1;
>  	bool type_invert:1;
> +	bool handle_reread:1;
>  
>  	int num_regs;
>  

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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