linux-kernel - [PATCH v3 05/10] gpio: pl061: Make the irqchip immutable

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Date:   Tue, 19 Apr 2022 15:18:41 +0100
From:   Marc Zyngier <maz@...nel.org>
To:     linux-kernel@...r.kernel.org
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Thierry Reding <thierry.reding@...il.com>,
        Joey Gouly <joey.gouly@....com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Hector Martin <marcan@...can.st>,
        Sven Peter <sven@...npeter.dev>,
        Alyssa Rosenzweig <alyssa@...enzweig.io>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Andy Gross <agross@...nel.org>,
        Jeffrey Hugo <jeffrey.l.hugo@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Basavaraj Natikar <Basavaraj.Natikar@....com>,
        Shyam Sundar S K <Shyam-sundar.S-k@....com>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        linux-gpio@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, kernel-team@...roid.com
Subject: [PATCH v3 05/10] gpio: pl061: Make the irqchip immutable

Prevent gpiolib from messing with the irqchip by advertising
the irq_chip structure as immutable, making it const, and adding
the various calls that gpiolib relies upon.

Reviewed-by: Bartosz Golaszewski <brgl@...ev.pl>
Signed-off-by: Marc Zyngier <maz@...nel.org>
---
 drivers/gpio/gpio-pl061.c | 32 +++++++++++++++++++++++---------
 1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/drivers/gpio/gpio-pl061.c b/drivers/gpio/gpio-pl061.c
index 4ecab700f23f..6464056cb6ae 100644
--- a/drivers/gpio/gpio-pl061.c
+++ b/drivers/gpio/gpio-pl061.c
@@ -52,7 +52,6 @@ struct pl061 {
 
 	void __iomem		*base;
 	struct gpio_chip	gc;
-	struct irq_chip		irq_chip;
 	int			parent_irq;
 
 #ifdef CONFIG_PM
@@ -241,6 +240,8 @@ static void pl061_irq_mask(struct irq_data *d)
 	gpioie = readb(pl061->base + GPIOIE) & ~mask;
 	writeb(gpioie, pl061->base + GPIOIE);
 	raw_spin_unlock(&pl061->lock);
+
+	gpiochip_disable_irq(gc, d->hwirq);
 }
 
 static void pl061_irq_unmask(struct irq_data *d)
@@ -250,6 +251,8 @@ static void pl061_irq_unmask(struct irq_data *d)
 	u8 mask = BIT(irqd_to_hwirq(d) % PL061_GPIO_NR);
 	u8 gpioie;
 
+	gpiochip_enable_irq(gc, d->hwirq);
+
 	raw_spin_lock(&pl061->lock);
 	gpioie = readb(pl061->base + GPIOIE) | mask;
 	writeb(gpioie, pl061->base + GPIOIE);
@@ -283,6 +286,24 @@ static int pl061_irq_set_wake(struct irq_data *d, unsigned int state)
 	return irq_set_irq_wake(pl061->parent_irq, state);
 }
 
+static void pl061_irq_print_chip(struct irq_data *data, struct seq_file *p)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+
+	seq_printf(p, dev_name(gc->parent));
+}
+
+static const struct irq_chip pl061_irq_chip = {
+	.irq_ack		= pl061_irq_ack,
+	.irq_mask		= pl061_irq_mask,
+	.irq_unmask		= pl061_irq_unmask,
+	.irq_set_type		= pl061_irq_type,
+	.irq_set_wake		= pl061_irq_set_wake,
+	.irq_print_chip		= pl061_irq_print_chip,
+	.flags			= IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
 static int pl061_probe(struct amba_device *adev, const struct amba_id *id)
 {
 	struct device *dev = &adev->dev;
@@ -315,13 +336,6 @@ static int pl061_probe(struct amba_device *adev, const struct amba_id *id)
 	/*
 	 * irq_chip support
 	 */
-	pl061->irq_chip.name = dev_name(dev);
-	pl061->irq_chip.irq_ack	= pl061_irq_ack;
-	pl061->irq_chip.irq_mask = pl061_irq_mask;
-	pl061->irq_chip.irq_unmask = pl061_irq_unmask;
-	pl061->irq_chip.irq_set_type = pl061_irq_type;
-	pl061->irq_chip.irq_set_wake = pl061_irq_set_wake;
-
 	writeb(0, pl061->base + GPIOIE); /* disable irqs */
 	irq = adev->irq[0];
 	if (!irq)
@@ -329,7 +343,7 @@ static int pl061_probe(struct amba_device *adev, const struct amba_id *id)
 	pl061->parent_irq = irq;
 
 	girq = &pl061->gc.irq;
-	girq->chip = &pl061->irq_chip;
+	gpio_irq_chip_set_chip(girq, &pl061_irq_chip);
 	girq->parent_handler = pl061_irq_handler;
 	girq->num_parents = 1;
 	girq->parents = devm_kcalloc(dev, 1, sizeof(*girq->parents),
-- 
2.34.1