Thread (19 messages) 19 messages, 3 authors, 1d ago

Re: [PATCH 08/12] soc: fsl: qe: Convert to generic IRQ chip

From: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Date: 2026-07-06 07:29:43
Also in: linux-arm-kernel, linux-devicetree, linux-gpio, lkml

Hi Paul,

Le 03/07/2026 à 15:30, Paul Louvel a écrit :
quoted hunk ↗ jump to hunk
The generic IRQ chip framework is available to handle IRQ chips. Using
this framework for the QE interrupt controller allows to simplify the
driver. Indeed, the framework internally handles operations coded
directly in the driver.

Add a select dependency to GENERIC_IRQ_CHIP in the PPC platform Kconfig.

Signed-off-by: Paul Louvel <redacted>
---
  arch/powerpc/platforms/Kconfig   |   1 +
  drivers/soc/fsl/qe/qe_ports_ic.c | 103 ++++++++++++++++++++++++++-------------
  2 files changed, 70 insertions(+), 34 deletions(-)
diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
index c4e61843d9d9..b0b3a80f8cde 100644
--- a/arch/powerpc/platforms/Kconfig
+++ b/arch/powerpc/platforms/Kconfig
@@ -232,6 +232,7 @@ config QE_GPIO
  	bool "QE GPIO support"
  	depends on QUICC_ENGINE
  	select GPIOLIB
+	select GENERIC_IRQ_CHIP
  	help
  	  Say Y here if you're going to use hardware that connects to the
  	  QE GPIOs.
diff --git a/drivers/soc/fsl/qe/qe_ports_ic.c b/drivers/soc/fsl/qe/qe_ports_ic.c
index c8b73b0aa233..d022aa224f6d 100644
--- a/drivers/soc/fsl/qe/qe_ports_ic.c
+++ b/drivers/soc/fsl/qe/qe_ports_ic.c
@@ -20,63 +20,65 @@ struct qepic_data {
  	void __iomem *reg;
  	struct irq_domain *host;
  	int irq;
+	struct irq_chip_generic *gc;
  };
  
  static void qepic_mask(struct irq_data *d)
  {
-	struct qepic_data *data = irq_data_get_irq_chip_data(d);
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct irq_chip_type *ct = irq_data_get_chip_type(d);
  
-	clrbits32(data->reg + CEPIMR, 1 << (31 - irqd_to_hwirq(d)));
+	clrbits32(gc->reg_base + ct->regs.mask, d->mask);
Is there a real added value with this change ?

Previously we had:

00000000 <qepic_mask>:
    0:	81 03 00 18 	lwz     r8,24(r3)
    4:	81 28 00 00 	lwz     r9,0(r8)
    8:	7c 00 04 ac 	hwsync
    c:	81 29 00 10 	lwz     r9,16(r9)
   10:	0c 09 00 00 	twi     0,r9,0
   14:	4c 00 01 2c 	isync
   18:	80 e3 00 08 	lwz     r7,8(r3)
   1c:	3d 40 80 00 	lis     r10,-32768
   20:	81 08 00 00 	lwz     r8,0(r8)
   24:	7d 4a 3c 30 	srw     r10,r10,r7
   28:	7d 29 50 78 	andc    r9,r9,r10
   2c:	7c 00 04 ac 	hwsync
   30:	91 28 00 10 	stw     r9,16(r8)
   34:	4e 80 00 20 	blr

Now we have:

00000000 <qepic_mask>:
    0:	80 e3 00 18 	lwz     r7,24(r3)
    4:	81 03 00 10 	lwz     r8,16(r3)
    8:	81 27 00 00 	lwz     r9,0(r7)
    c:	81 48 00 94 	lwz     r10,148(r8)
   10:	7d 29 52 14 	add     r9,r9,r10
   14:	7c 00 04 ac 	hwsync
   18:	81 49 00 00 	lwz     r10,0(r9)
   1c:	0c 0a 00 00 	twi     0,r10,0
   20:	4c 00 01 2c 	isync
   24:	80 c3 00 00 	lwz     r6,0(r3)
   28:	81 27 00 00 	lwz     r9,0(r7)
   2c:	81 08 00 94 	lwz     r8,148(r8)
   30:	7d 4a 30 78 	andc    r10,r10,r6
   34:	7d 29 42 14 	add     r9,r9,r8
   38:	7c 00 04 ac 	hwsync
   3c:	91 49 00 00 	stw     r10,0(r9)
   40:	4e 80 00 20 	blr

We now have three more indirect loads (8x lwz instead of 5x), for 
loading some value which is already known at compile time.

quoted hunk ↗ jump to hunk
  }
  
  static void qepic_unmask(struct irq_data *d)
  {
-	struct qepic_data *data = irq_data_get_irq_chip_data(d);
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct irq_chip_type *ct = irq_data_get_chip_type(d);
  
-	setbits32(data->reg + CEPIMR, 1 << (31 - irqd_to_hwirq(d)));
+	setbits32(gc->reg_base + ct->regs.mask, d->mask);
  }
  
  static void qepic_end(struct irq_data *d)
  {
-	struct qepic_data *data = irq_data_get_irq_chip_data(d);
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct irq_chip_type *ct = irq_data_get_chip_type(d);
  
-	out_be32(data->reg + CEPIER, 1 << (31 - irqd_to_hwirq(d)));
+	out_be32(gc->reg_base + ct->regs.eoi, d->mask);
+}
+
+static void qepic_calc_mask(struct irq_data *d)
+{
+	d->mask = 1 << (31 - irqd_to_hwirq(d));
  }
  
  static int qepic_set_type(struct irq_data *d, unsigned int flow_type)
  {
-	struct qepic_data *data = irq_data_get_irq_chip_data(d);
-	unsigned int vec = (unsigned int)irqd_to_hwirq(d);
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct irq_chip_type *ct = irq_data_get_chip_type(d);
  
  	switch (flow_type & IRQ_TYPE_SENSE_MASK) {
  	case IRQ_TYPE_EDGE_FALLING:
-		setbits32(data->reg + CEPICR, 1 << (31 - vec));
+		setbits32(gc->reg_base + ct->regs.type, d->mask);
  		return 0;
  	case IRQ_TYPE_EDGE_BOTH:
  	case IRQ_TYPE_NONE:
-		clrbits32(data->reg + CEPICR, 1 << (31 - vec));
+		clrbits32(gc->reg_base + ct->regs.type, d->mask);
  		return 0;
  	}
  	return -EINVAL;
  }
  
-static struct irq_chip qepic = {
-	.name = "QEPIC",
-	.irq_mask = qepic_mask,
-	.irq_unmask = qepic_unmask,
-	.irq_eoi = qepic_end,
-	.irq_set_type = qepic_set_type,
-};
-
  static void qepic_cascade(struct irq_desc *desc)
  {
  	struct qepic_data *data = irq_desc_get_handler_data(desc);
+	struct irq_chip_type *ct = data->gc->chip_types;
  	struct irq_chip *chip = irq_desc_get_chip(desc);
  	unsigned long event, bit;
  
  	chained_irq_enter(chip, desc);
  
-	event = in_be32(data->reg + CEPIER);
+	event = in_be32(data->gc->reg_base + ct->regs.eoi);
  	if (!event) {
  		handle_bad_irq(desc);
  		goto out;
@@ -89,33 +91,64 @@ static void qepic_cascade(struct irq_desc *desc)
  	chained_irq_exit(chip, desc);
  }
  
-static int qepic_host_map(struct irq_domain *h, unsigned int virq, irq_hw_number_t hw)
+static int qepic_chip_init(struct irq_chip_generic *gc)
  {
-	irq_set_chip_data(virq, h->host_data);
-	irq_set_chip_and_handler(virq, &qepic, handle_fasteoi_irq);
+	struct irq_chip_type *ct = gc->chip_types;
+
+	ct->regs.mask = CEPIMR;
+	ct->chip.irq_mask = qepic_mask;
+	ct->chip.irq_unmask = qepic_unmask;
+	ct->regs.eoi = CEPIER;
+	ct->chip.irq_eoi = qepic_end;
+	ct->regs.type = CEPICR;
+	ct->chip.irq_set_type = qepic_set_type;
+	ct->chip.irq_calc_mask = qepic_calc_mask;
Are ct->regs.mask, ct->regs.eoi and ct->regs.type used anywhere else 
than locally in qepic_{mask/unmask/end/set_type} ?

Christophe
quoted hunk ↗ jump to hunk
+
  	return 0;
  }
  
-static const struct irq_domain_ops qepic_host_ops = {
-	.map = qepic_host_map,
-};
+static int qepic_domain_init(struct irq_domain *d)
+{
+	struct qepic_data *data = d->host_data;
  
-static void qepic_remove(void *res)
+	irq_set_chained_handler_and_data(data->irq, qepic_cascade, data);
+
+	return 0;
+}
+
+static void qepic_domain_exit(struct irq_domain *d)
  {
-	struct qepic_data *data = res;
+	struct qepic_data *data = d->host_data;
  
  	irq_set_chained_handler_and_data(data->irq, NULL, NULL);
-	irq_domain_remove(data->host);
  }
  
  static int qepic_probe(struct platform_device *pdev)
  {
+	struct irq_domain_chip_generic_info dgc_info = {
+		.name		= "QEPIC",
+		.handler	= handle_fasteoi_irq,
+		.irqs_per_chip	= 32,
+		.num_ct		= 1,
+		.init		= qepic_chip_init,
+	};
+	struct irq_domain_info d_info = {
+		.fwnode		= of_fwnode_handle(pdev->dev.of_node),
+		.domain_flags	= IRQ_DOMAIN_FLAG_DESTROY_GC,
+		.size		= 32,
+		.hwirq_max	= 32,
+		.ops		= &irq_generic_chip_ops,
+		.dgc_info	= &dgc_info,
+		.init		= qepic_domain_init,
+		.exit		= qepic_domain_exit,
+	};
  	struct device *dev = &pdev->dev;
  	struct qepic_data *data;
  
  	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
  	if (!data)
  		return -ENOMEM;
+	d_info.host_data = data;
  
  	data->reg = devm_platform_ioremap_resource(pdev, 0);
  	if (IS_ERR(data->reg))
@@ -125,14 +158,16 @@ static int qepic_probe(struct platform_device *pdev)
  	if (data->irq < 0)
  		return data->irq;
  
-	data->host = irq_domain_create_linear(dev_fwnode(dev), 32, &qepic_host_ops, data);
-	if (!data->host)
-		return -ENODEV;
+	data->host = devm_irq_domain_instantiate(dev, &d_info);
+	if (IS_ERR(data->host))
+		return PTR_ERR(data->host);
  
-	irq_set_chained_handler_and_data(data->irq, qepic_cascade, data);
-
-	return devm_add_action_or_reset(dev, qepic_remove, data);
+	data->gc = irq_get_domain_generic_chip(data->host, 0);
+	if (!data->gc)
+		return -ENODEV;
+	data->gc->reg_base = data->reg;
  
+	return 0;
  }
  
  static const struct of_device_id qepic_match[] = {
  
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