Re: [PATCH v4 09/14] irqchip: Provide platform_device to of_irq_init_cb_t

[Marc Zyngier]

On Sat, 09 Oct 2021 03:20:18 +0100,
Florian Fainelli <f.fainelli@xxxxxxxxx> wrote:
> 
> Provide the platform device mapping to the interrupt controller node to
> the of_irq_init_cb_t callback such that drivers can make use of it.
> 
> Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
> Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
> ---
>  drivers/irqchip/irqchip.c  | 2 +-
>  drivers/irqchip/qcom-pdc.c | 3 ++-
>  drivers/of/irq.c           | 2 +-
>  include/linux/of_irq.h     | 5 ++++-
>  4 files changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/irqchip/irqchip.c b/drivers/irqchip/irqchip.c
> index 3570f0a588c4..289784eefd00 100644
> --- a/drivers/irqchip/irqchip.c
> +++ b/drivers/irqchip/irqchip.c
> @@ -55,6 +55,6 @@ int platform_irqchip_probe(struct platform_device *pdev)
>  	if (par_np && !irq_find_matching_host(par_np, DOMAIN_BUS_ANY))
>  		return -EPROBE_DEFER;
>  
> -	return irq_init_cb(np, par_np);
> +	return irq_init_cb(np, par_np, pdev);
>  }
>  EXPORT_SYMBOL_GPL(platform_irqchip_probe);
> diff --git a/drivers/irqchip/qcom-pdc.c b/drivers/irqchip/qcom-pdc.c
> index 173e6520e06e..819a93360b96 100644
> --- a/drivers/irqchip/qcom-pdc.c
> +++ b/drivers/irqchip/qcom-pdc.c
> @@ -359,7 +359,8 @@ static int pdc_setup_pin_mapping(struct device_node *np)
>  	return 0;
>  }
>  
> -static int qcom_pdc_init(struct device_node *node, struct device_node *parent)
> +static int qcom_pdc_init(struct device_node *node, struct device_node *parent,
> +			 struct platform_device *pdev)
>  {
>  	struct irq_domain *parent_domain, *pdc_domain, *pdc_gpio_domain;
>  	int ret;
> diff --git a/drivers/of/irq.c b/drivers/of/irq.c
> index 352e14b007e7..18f3f5c00c87 100644
> --- a/drivers/of/irq.c
> +++ b/drivers/of/irq.c
> @@ -538,7 +538,7 @@ void __init of_irq_init(const struct of_device_id *matches)
>  				 desc->dev,
>  				 desc->dev, desc->interrupt_parent);
>  			ret = desc->irq_init_cb(desc->dev,
> -						desc->interrupt_parent);
> +						desc->interrupt_parent, NULL);
>  			if (ret) {
>  				of_node_clear_flag(desc->dev, OF_POPULATED);
>  				kfree(desc);
> diff --git a/include/linux/of_irq.h b/include/linux/of_irq.h
> index aaf219bd0354..89acc8b089f0 100644
> --- a/include/linux/of_irq.h
> +++ b/include/linux/of_irq.h
> @@ -9,7 +9,10 @@
>  #include <linux/ioport.h>
>  #include <linux/of.h>
>  
> -typedef int (*of_irq_init_cb_t)(struct device_node *, struct device_node *);
> +struct platform_device;
> +
> +typedef int (*of_irq_init_cb_t)(struct device_node *, struct device_node *,
> +				struct platform_device *);

Having added some type-checking to the IRQCHIP_MATCH() #definery, I
end-up with warnings such as:

In file included from ./include/linux/kernel.h:16,
                 from drivers/irqchip/irq-bcm7038-l1.c:12:
./include/linux/minmax.h:20:28: warning: comparison of distinct pointer types lacks a cast
   20 |  (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
      |                            ^~
./include/linux/irqchip.h:41:2: note: in expansion of macro ‘__typecheck’
   41 |  __typecheck(typecheck_irq_init_cb, fn) ? fn : fn
      |  ^~~~~~~~~~~
./include/linux/irqchip.h:44:12: note: in expansion of macro ‘typecheck_irq_init_cb’
   44 |    .data = typecheck_irq_init_cb(fn), },
      |            ^~~~~~~~~~~~~~~~~~~~~
drivers/irqchip/irq-bcm7038-l1.c:459:1: note: in expansion of macro ‘IRQCHIP_MATCH’
  459 | IRQCHIP_MATCH("brcm,bcm7038-l1-intc", bcm7038_l1_of_init)
      | ^~~~~~~~~~~~~

Clearly, you didn't update the drivers you just converted to
IRQCHIP_MATCH(), and only fixed the QC driver.

FWIW, I'm planning to take something like the hack below into the tree
to detect this sort of stuff early.

	M.

diff --git a/include/linux/irqchip.h b/include/linux/irqchip.h
index ccf32758ea85..146a9d80a6a2 100644
--- a/include/linux/irqchip.h
+++ b/include/linux/irqchip.h
@@ -33,7 +33,15 @@ extern int platform_irqchip_probe(struct platform_device *pdev);
 #define IRQCHIP_PLATFORM_DRIVER_BEGIN(drv_name) \
 static const struct of_device_id drv_name##_irqchip_match_table[] = {
 
-#define IRQCHIP_MATCH(compat, fn) { .compatible = compat, .data = fn },
+/* Undefined on purpose */
+int typecheck_irq_init_cb(struct device_node *, struct device_node *,
+			  struct platform_device *);
+
+#define typecheck_irq_init_cb(fn)					\
+	__typecheck(typecheck_irq_init_cb, fn) ? fn : fn
+
+#define IRQCHIP_MATCH(compat, fn) { .compatible = compat,	\
+			.data = typecheck_irq_init_cb(fn), },
 
 #define IRQCHIP_PLATFORM_DRIVER_END(drv_name)				\
 	{},								\

-- 
Without deviation from the norm, progress is not possible.