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Subject[PATCH 2/3] irqchip: Add support to remove irqchip driver modules.
Date
The existing irqchip implementation does not fully support use cases
where an irqchip driver has to be used as a module. In particular there
is no support to remove an irqchip driver module.
The use cases where an irqchip driver has to be loaded and then removed
as a module are really relevant in fpga world. A user can decide to
have a irqchip as part of a removable partial fpga region. In such cases
not only the corresponding irqchip driver has to be loaded as a module,
but must also be removed when the removable partial region is removed.

The existing implementation updates the existing framework to achieve
the above said goal.

Signed-off-by: Anirudha Sarangi <anirudha.sarangi@xilinx.com>
---
drivers/irqchip/irqchip.c | 38 +++++++++++++++++++++++++++++++++++---
include/linux/irq.h | 13 +++++++++++++
include/linux/of_irq.h | 1 +
3 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irqchip.c b/drivers/irqchip/irqchip.c
index 3570f0a588c4..8687131e7268 100644
--- a/drivers/irqchip/irqchip.c
+++ b/drivers/irqchip/irqchip.c
@@ -15,6 +15,11 @@
#include <linux/irqchip.h>
#include <linux/platform_device.h>

+struct platform_irqchip_instance {
+ of_irq_init_cb_t irq_init_cb;
+ of_irq_remove_cb_t irq_remove_cb;
+};
+
/*
* This special of_device_id is the sentinel at the end of the
* of_device_id[] array of all irqchips. It is automatically placed at
@@ -34,11 +39,22 @@ void __init irqchip_init(void)

int platform_irqchip_probe(struct platform_device *pdev)
{
+ struct platform_irqchip_instance *irqchip;
+ const struct irqc_init_remove_funps *irqchip_funps;
struct device_node *np = pdev->dev.of_node;
struct device_node *par_np = of_irq_find_parent(np);
- of_irq_init_cb_t irq_init_cb = of_device_get_match_data(&pdev->dev);

- if (!irq_init_cb)
+ irqchip = devm_kzalloc(&pdev->dev, sizeof(*irqchip), GFP_KERNEL);
+ if (!irqchip)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, irqchip);
+
+ irqchip_funps = of_device_get_match_data(&pdev->dev);
+ irqchip->irq_init_cb = irqchip_funps->irqchip_initp;
+ irqchip->irq_remove_cb = irqchip_funps->irqchip_removep;
+
+ if (!irqchip->irq_init_cb)
return -EINVAL;

if (par_np == np)
@@ -55,6 +71,22 @@ 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 irqchip->irq_init_cb(np, par_np);
}
EXPORT_SYMBOL_GPL(platform_irqchip_probe);
+
+int platform_irqchip_remove(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct device_node *par_np = of_irq_find_parent(np);
+ struct platform_irqchip_instance *irqchip = platform_get_drvdata(pdev);
+
+ if (!irqchip->irq_remove_cb)
+ return -EINVAL;
+
+ if (par_np == np)
+ par_np = NULL;
+
+ return irqchip->irq_remove_cb(np, par_np);
+}
+EXPORT_SYMBOL_GPL(platform_irqchip_remove);
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 252fab8074de..d46d28f56bc0 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -1098,6 +1098,19 @@ struct irq_domain_chip_generic {
struct irq_chip_generic *gc[];
};

+/**
+ * struct irqc_init_remove_funps - Stores function pointers for irqc init
+ * and remove APIs. Used when the irqchip driver is to be used as a module.
+ * @irqchip_initp: Function pointer for init/entry point of a irqchip driver.
+ * @irqchip_removep:Function pointer for irqchip driver remove function.
+ */
+struct irqc_init_remove_funps {
+ int (*irqchip_initp)(struct device_node *irqc,
+ struct device_node *parent);
+ int (*irqchip_removep)(struct device_node *irqc,
+ struct device_node *parent);
+};
+
/* Generic chip callback functions */
void irq_gc_noop(struct irq_data *d);
void irq_gc_mask_disable_reg(struct irq_data *d);
diff --git a/include/linux/of_irq.h b/include/linux/of_irq.h
index aaf219bd0354..4210ac64956f 100644
--- a/include/linux/of_irq.h
+++ b/include/linux/of_irq.h
@@ -10,6 +10,7 @@
#include <linux/of.h>

typedef int (*of_irq_init_cb_t)(struct device_node *, struct device_node *);
+typedef int (*of_irq_remove_cb_t)(struct device_node *, struct device_node *);

/*
* Workarounds only applied to 32bit powermac machines
--
2.17.1
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