linux-kernel - [PATCH RFC 07/14] genirq: Introduce irq_chip_get/set_parent

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Date:   Thu, 29 Aug 2019 12:11:56 -0600
From:   Lina Iyer <ilina@...eaurora.org>
To:     swboyd@...omium.org, evgreen@...omium.org, marc.zyngier@....com,
        linus.walleij@...aro.org
Cc:     linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        bjorn.andersson@...aro.org, mkshah@...eaurora.org,
        linux-gpio@...r.kernel.org, rnayak@...eaurora.org
Subject: [PATCH RFC 07/14] genirq: Introduce irq_chip_get/set_parent_state calls

From: Maulik Shah <mkshah@...eaurora.org>

On certain QTI chipsets some GPIOs are direct-connect interrupts
to the GIC.

Even when GPIOs are not used for interrupt generation and interrupt
line is disabled, it does not prevent interrupt to get pending at
GIC_ISPEND. When drivers call enable_irq unwanted interrupt occures.

Introduce irq_chip_get/set_parent_state calls to clear pending irq
which can get called within irq_enable of child irq chip to clear
any pending irq before enabling.

Signed-off-by: Maulik Shah <mkshah@...eaurora.org>
---
 include/linux/irq.h |  6 ++++++
 kernel/irq/chip.c   | 44 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index fb301cf29148..7853eb9301f2 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -610,6 +610,12 @@ extern int irq_chip_pm_put(struct irq_data *data);
 #ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
 extern void handle_fasteoi_ack_irq(struct irq_desc *desc);
 extern void handle_fasteoi_mask_irq(struct irq_desc *desc);
+extern int irq_chip_set_parent_state(struct irq_data *data,
+				     enum irqchip_irq_state which,
+				     bool val);
+extern int irq_chip_get_parent_state(struct irq_data *data,
+				     enum irqchip_irq_state which,
+				     bool *state);
 extern void irq_chip_enable_parent(struct irq_data *data);
 extern void irq_chip_disable_parent(struct irq_data *data);
 extern void irq_chip_ack_parent(struct irq_data *data);
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index b76703b2c0af..6bb5b22bb0a7 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -1297,6 +1297,50 @@ EXPORT_SYMBOL_GPL(handle_fasteoi_mask_irq);
 
 #endif /* CONFIG_IRQ_FASTEOI_HIERARCHY_HANDLERS */
 
+/**
+ *	irq_chip_set_parent_state - set the state of a parent interrupt.
+ *	@data: Pointer to interrupt specific data
+ *	@which: State to be restored (one of IRQCHIP_STATE_*)
+ *	@val: Value corresponding to @which
+ *
+ */
+int irq_chip_set_parent_state(struct irq_data *data,
+			      enum irqchip_irq_state which,
+			      bool val)
+{
+	data = data->parent_data;
+	if (!data)
+		return 0;
+
+	if (data->chip->irq_set_irqchip_state)
+		return data->chip->irq_set_irqchip_state(data, which, val);
+
+	return 0;
+}
+EXPORT_SYMBOL(irq_chip_set_parent_state);
+
+/**
+ *	irq_chip_get_parent_state - get the state of a parent interrupt.
+ *	@data: Pointer to interrupt specific data
+ *	@which: one of IRQCHIP_STATE_* the caller wants to know
+ *	@state: a pointer to a boolean where the state is to be stored
+ *
+ */
+int irq_chip_get_parent_state(struct irq_data *data,
+			      enum irqchip_irq_state which,
+			      bool *state)
+{
+	data = data->parent_data;
+	if (!data)
+		return 0;
+
+	if (data->chip->irq_get_irqchip_state)
+		return data->chip->irq_get_irqchip_state(data, which, state);
+
+	return 0;
+}
+EXPORT_SYMBOL(irq_chip_get_parent_state);
+
 /**
  * irq_chip_enable_parent - Enable the parent interrupt (defaults to unmask if
  * NULL)
-- 
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