[PATCH v4 1/3] gpio: xgene: Enable X-Gene standby GPIO as interrupt controller

[Quan Nguyen <qnguyen@xxxxxxx>]

Enable X-Gene standby GPIO controller as interrupt controller to provide
its own resources. This avoids ambiguity where GIC interrupt resource is
use as X-Gene standby GPIO interrupt resource in user driver.

Signed-off-by: Y Vo <yvo@xxxxxxx>
Signed-off-by: Quan Nguyen <qnguyen@xxxxxxx>
---
 drivers/gpio/gpio-xgene-sb.c | 331 ++++++++++++++++++++++++++++++++++++-------
 1 file changed, 276 insertions(+), 55 deletions(-)

diff --git a/drivers/gpio/gpio-xgene-sb.c b/drivers/gpio/gpio-xgene-sb.c
index 282004d..b703114 100644
--- a/drivers/gpio/gpio-xgene-sb.c
+++ b/drivers/gpio/gpio-xgene-sb.c
@@ -2,8 +2,9 @@
  * AppliedMicro X-Gene SoC GPIO-Standby Driver
  *
  * Copyright (c) 2014, Applied Micro Circuits Corporation
- * Author: 	Tin Huynh <tnhuynh@xxxxxxx>.
- * 		Y Vo <yvo@xxxxxxx>.
+ * Author:	Tin Huynh <tnhuynh@xxxxxxx>.
+ *		Y Vo <yvo@xxxxxxx>.
+ *		Quan Nguyen <qnguyen@xxxxxxx>.
  *
  * This program is free software; you can redistribute  it and/or modify it
  * under  the terms of  the GNU General  Public License as published by the
@@ -22,14 +23,20 @@
 #include <linux/module.h>
 #include <linux/io.h>
 #include <linux/platform_device.h>
+#include <linux/of_platform.h>
 #include <linux/of_gpio.h>
+#include <linux/of_irq.h>
 #include <linux/gpio/driver.h>
 #include <linux/acpi.h>
 
 #include "gpiolib.h"
 
-#define XGENE_MAX_GPIO_DS		22
-#define XGENE_MAX_GPIO_DS_IRQ		6
+#define XGENE_MAX_NGPIO			22
+#define XGENE_MAX_NIRQ			6
+#define XGENE_IRQ_START_PIN		8
+#define SBGPIO_XGENE			((XGENE_IRQ_START_PIN << 24) | \
+					(XGENE_MAX_NIRQ << 16) | \
+					(XGENE_MAX_NGPIO << 8))
 
 #define GPIO_MASK(x)			(1U << ((x) % 32))
 
@@ -39,19 +46,30 @@
 #define MPA_GPIO_IN_ADDR 		0x02a4
 #define MPA_GPIO_SEL_LO 		0x0294
 
+#define GPIO_INT_LEVEL_H	0x000001
+#define GPIO_INT_LEVEL_L	0x000000
+
 /**
  * struct xgene_gpio_sb - GPIO-Standby private data structure.
  * @gc:				memory-mapped GPIO controllers.
- * @irq:			Mapping GPIO pins and interrupt number
- * nirq:			Number of GPIO pins that supports interrupt
+ * @regs:			GPIO register base offset
+ * @irq_domain:			GPIO interrupt domain
+ * flags:			GPIO per-instance flags assigned by the driver
  */
 struct xgene_gpio_sb {
 	struct gpio_chip	gc;
-	u32 *irq;
-	u32 nirq;
+	void __iomem		*regs;
+	struct irq_domain	*irq_domain;
+	u32			flags;
 };
 
-static void xgene_gpio_set_bit(struct gpio_chip *gc, void __iomem *reg, u32 gpio, int val)
+#define IRQ_START_PIN(priv)	(((priv)->flags >> 24) & 0xff)
+#define NIRQ_MAX(priv)		(((priv)->flags >> 16) & 0xff)
+#define NGPIO_MAX(priv)		(((priv)->flags >>  8) & 0xff)
+#define START_PARENT_IRQ(priv)	((priv)->flags & 0xff)
+
+static void xgene_gpio_set_bit(struct gpio_chip *gc,
+				void __iomem *reg, u32 gpio, int val)
 {
 	u32 data;
 
@@ -63,23 +81,216 @@ static void xgene_gpio_set_bit(struct gpio_chip *gc, void __iomem *reg, u32 gpio
 	gc->write_reg(reg, data);
 }
 
-static int apm_gpio_sb_to_irq(struct gpio_chip *gc, u32 gpio)
+static int xgene_gpio_sb_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct xgene_gpio_sb *priv = irq_data_get_irq_chip_data(d);
+	int gpio = d->hwirq + IRQ_START_PIN(priv);
+	int lvl_type;
+	int ret;
+
+	switch (type & IRQ_TYPE_SENSE_MASK) {
+	case IRQ_TYPE_EDGE_RISING:
+	case IRQ_TYPE_LEVEL_HIGH:
+		lvl_type = GPIO_INT_LEVEL_H;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+	case IRQ_TYPE_LEVEL_LOW:
+		lvl_type = GPIO_INT_LEVEL_L;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = gpiochip_lock_as_irq(&priv->gc, gpio);
+	if (ret) {
+		dev_err(priv->gc.parent,
+		"Unable to configure XGene GPIO standby pin %d as IRQ\n",
+				gpio);
+		return ret;
+	}
+
+	if ((gpio >= IRQ_START_PIN(priv)) &&
+			(d->hwirq < NIRQ_MAX(priv))) {
+		xgene_gpio_set_bit(&priv->gc, priv->regs + MPA_GPIO_SEL_LO,
+				gpio * 2, 1);
+		xgene_gpio_set_bit(&priv->gc, priv->regs + MPA_GPIO_INT_LVL,
+				d->hwirq, lvl_type);
+	}
+
+	/* Propagate IRQ type setting to parent */
+	if (type & IRQ_TYPE_EDGE_BOTH)
+		return irq_chip_set_type_parent(d, IRQ_TYPE_EDGE_RISING);
+	else
+		return irq_chip_set_type_parent(d, IRQ_TYPE_LEVEL_HIGH);
+}
+
+static void xgene_gpio_sb_irq_shutdown(struct irq_data *d)
+{
+	struct xgene_gpio_sb *priv = irq_data_get_irq_chip_data(d);
+
+	gpiochip_unlock_as_irq(&priv->gc, d->hwirq + IRQ_START_PIN(priv));
+}
+
+static struct irq_chip xgene_gpio_sb_irq_chip = {
+	.name           = "sbgpio",
+	.irq_ack        = irq_chip_ack_parent,
+	.irq_eoi	= irq_chip_eoi_parent,
+	.irq_mask       = irq_chip_mask_parent,
+	.irq_unmask     = irq_chip_unmask_parent,
+	.irq_set_type   = xgene_gpio_sb_irq_set_type,
+	.irq_shutdown   = xgene_gpio_sb_irq_shutdown,
+};
+
+static int xgene_gpio_sb_to_irq(struct gpio_chip *gc, u32 gpio)
 {
 	struct xgene_gpio_sb *priv = gpiochip_get_data(gc);
+	struct irq_fwspec fwspec;
+	unsigned int virq;
+
+	if ((gpio < IRQ_START_PIN(priv)) ||
+			(gpio > NIRQ_MAX(priv) + IRQ_START_PIN(priv)))
+		return -ENXIO;
+	if (gc->parent->of_node)
+		fwspec.fwnode = of_node_to_fwnode(gc->parent->of_node);
+	else
+		fwspec.fwnode = gc->parent->fwnode;
+	fwspec.param_count = 2;
+	fwspec.param[0] = gpio - IRQ_START_PIN(priv);
+	fwspec.param[1] = IRQ_TYPE_NONE;
+	virq = irq_find_mapping(priv->irq_domain, gpio - IRQ_START_PIN(priv));
+	if (!virq)
+		virq =  irq_domain_alloc_irqs(priv->irq_domain, 1,
+						NUMA_NO_NODE, &fwspec);
+	return virq;
+}
+
+static void xgene_gpio_sb_domain_activate(struct irq_domain *d,
+		struct irq_data *irq_data)
+{
+	struct xgene_gpio_sb *priv = d->host_data;
+	u32 gpio = irq_data->hwirq + IRQ_START_PIN(priv);
 
-	if (priv->irq[gpio])
-		return priv->irq[gpio];
+	if ((gpio < IRQ_START_PIN(priv)) ||
+			(gpio > NIRQ_MAX(priv) + IRQ_START_PIN(priv)))
+		return;
 
-	return -ENXIO;
+	xgene_gpio_set_bit(&priv->gc, priv->regs + MPA_GPIO_SEL_LO,
+			gpio * 2, 1);
+}
+
+static void xgene_gpio_sb_domain_deactivate(struct irq_domain *d,
+		struct irq_data *irq_data)
+{
+	struct xgene_gpio_sb *priv = d->host_data;
+	u32 gpio = irq_data->hwirq + IRQ_START_PIN(priv);
+
+	if ((gpio < IRQ_START_PIN(priv)) ||
+			(gpio > NIRQ_MAX(priv) + IRQ_START_PIN(priv)))
+		return;
+
+	xgene_gpio_set_bit(&priv->gc, priv->regs + MPA_GPIO_SEL_LO,
+			gpio * 2, 0);
+}
+
+static int xgene_gpio_sb_domain_translate(struct irq_domain *d,
+		struct irq_fwspec *fwspec,
+		unsigned long *hwirq,
+		unsigned int *type)
+{
+	if (fwspec->param_count != 2)
+		return -EINVAL;
+	*hwirq = fwspec->param[0];
+	*type = fwspec->param[1];
+	return 0;
+}
+
+static int xgene_gpio_sb_domain_alloc(struct irq_domain *domain,
+					unsigned int virq,
+					unsigned int nr_irqs, void *data)
+{
+	struct irq_fwspec *fwspec = data;
+	struct irq_fwspec parent_fwspec;
+	struct xgene_gpio_sb *priv = domain->host_data;
+	irq_hw_number_t hwirq;
+	unsigned int type = IRQ_TYPE_NONE;
+	unsigned int i;
+	u32 ret;
+
+	ret = xgene_gpio_sb_domain_translate(domain, fwspec, &hwirq, &type);
+	if (ret)
+		return ret;
+
+	hwirq = fwspec->param[0];
+	if ((hwirq >= NIRQ_MAX(priv)) ||
+			(hwirq + nr_irqs > NIRQ_MAX(priv)))
+		return -EINVAL;
+
+	for (i = 0; i < nr_irqs; i++)
+		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
+				&xgene_gpio_sb_irq_chip, priv);
+
+	if (is_of_node(domain->parent->fwnode)) {
+		parent_fwspec.fwnode = domain->parent->fwnode;
+		parent_fwspec.param_count = 3;
+		parent_fwspec.param[0] = 0;/* SPI */
+		/* Skip SGIs and PPIs*/
+		parent_fwspec.param[1] = hwirq + START_PARENT_IRQ(priv) - 32;
+		parent_fwspec.param[2] = fwspec->param[1];
+	} else if (is_fwnode_irqchip(domain->parent->fwnode)) {
+		parent_fwspec.fwnode = domain->parent->fwnode;
+		parent_fwspec.param_count = 2;
+		parent_fwspec.param[0] = hwirq + START_PARENT_IRQ(priv);
+		parent_fwspec.param[1] = fwspec->param[1];
+	} else
+		return -EINVAL;
+
+	return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs,
+			&parent_fwspec);
+}
+
+static void xgene_gpio_sb_domain_free(struct irq_domain *domain,
+		unsigned int virq,
+		unsigned int nr_irqs)
+{
+	struct irq_data *d;
+	unsigned int i;
+
+	for (i = 0; i < nr_irqs; i++) {
+		d = irq_domain_get_irq_data(domain, virq + i);
+		irq_domain_reset_irq_data(d);
+	}
 }
 
+static const struct irq_domain_ops xgene_gpio_sb_domain_ops = {
+	.translate      = xgene_gpio_sb_domain_translate,
+	.alloc          = xgene_gpio_sb_domain_alloc,
+	.free           = xgene_gpio_sb_domain_free,
+	.activate	= xgene_gpio_sb_domain_activate,
+	.deactivate	= xgene_gpio_sb_domain_deactivate,
+};
+
+static const struct of_device_id xgene_gpio_sb_of_match[] = {
+	{.compatible = "apm,xgene-gpio-sb", .data = (const void *)SBGPIO_XGENE},
+	{},
+};
+MODULE_DEVICE_TABLE(of, xgene_gpio_sb_of_match);
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id xgene_gpio_sb_acpi_match[] = {
+	{"APMC0D15", SBGPIO_XGENE},
+	{},
+};
+MODULE_DEVICE_TABLE(acpi, xgene_gpio_sb_acpi_match);
+#endif
+
 static int xgene_gpio_sb_probe(struct platform_device *pdev)
 {
 	struct xgene_gpio_sb *priv;
-	u32 ret, i;
-	u32 default_lines[] = {0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D};
+	u32 ret;
 	struct resource *res;
 	void __iomem *regs;
+	const struct of_device_id *of_id;
+	struct irq_domain *parent_domain = NULL;
 
 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
@@ -90,6 +301,32 @@ static int xgene_gpio_sb_probe(struct platform_device *pdev)
 	if (IS_ERR(regs))
 		return PTR_ERR(regs);
 
+	priv->regs = regs;
+
+	of_id = of_match_device(xgene_gpio_sb_of_match, &pdev->dev);
+	if (of_id)
+		priv->flags = (uintptr_t)of_id->data;
+#ifdef CONFIG_ACPI
+	else {
+		const struct acpi_device_id *acpi_id;
+
+		acpi_id = acpi_match_device(xgene_gpio_sb_acpi_match,
+				&pdev->dev);
+		if (acpi_id)
+			priv->flags = (uintptr_t)acpi_id->driver_data;
+	}
+#endif
+	ret = platform_get_irq(pdev, 0);
+	if (ret > 0) {
+		priv->flags &= ~0xff;
+		priv->flags |= irq_get_irq_data(ret)->hwirq & 0xff;
+		parent_domain = irq_get_irq_data(ret)->domain;
+	}
+	if (!parent_domain) {
+		dev_err(&pdev->dev, "unable to obtain parent domain\n");
+		return -ENODEV;
+	}
+
 	ret = bgpio_init(&priv->gc, &pdev->dev, 4,
 			regs + MPA_GPIO_IN_ADDR,
 			regs + MPA_GPIO_OUT_ADDR, NULL,
@@ -97,36 +334,34 @@ static int xgene_gpio_sb_probe(struct platform_device *pdev)
         if (ret)
                 return ret;
 
-	priv->gc.to_irq = apm_gpio_sb_to_irq;
-	priv->gc.ngpio = XGENE_MAX_GPIO_DS;
-
-	priv->nirq = XGENE_MAX_GPIO_DS_IRQ;
+	priv->gc.to_irq = xgene_gpio_sb_to_irq;
+	priv->gc.ngpio = NGPIO_MAX(priv);
 
-	priv->irq = devm_kzalloc(&pdev->dev, sizeof(u32) * XGENE_MAX_GPIO_DS,
-				   GFP_KERNEL);
-	if (!priv->irq)
-		return -ENOMEM;
+	platform_set_drvdata(pdev, priv);
 
-	for (i = 0; i < priv->nirq; i++) {
-		priv->irq[default_lines[i]] = platform_get_irq(pdev, i);
-		xgene_gpio_set_bit(&priv->gc, regs + MPA_GPIO_SEL_LO,
-                                   default_lines[i] * 2, 1);
-		xgene_gpio_set_bit(&priv->gc, regs + MPA_GPIO_INT_LVL, i, 1);
-	}
+	priv->irq_domain = irq_domain_create_hierarchy(parent_domain,
+					0, NIRQ_MAX(priv),
+					of_node_to_fwnode(pdev->dev.of_node),
+					&xgene_gpio_sb_domain_ops, priv);
+	if (!priv->irq_domain)
+		return -ENODEV;
 
-	platform_set_drvdata(pdev, priv);
+	priv->gc.irqdomain = priv->irq_domain;
 
 	ret = gpiochip_add_data(&priv->gc, priv);
-	if (ret)
-		dev_err(&pdev->dev, "failed to register X-Gene GPIO Standby driver\n");
-	else
-		dev_info(&pdev->dev, "X-Gene GPIO Standby driver registered\n");
-
-	if (priv->nirq > 0) {
-		/* Register interrupt handlers for gpio signaled acpi events */
-		acpi_gpiochip_request_interrupts(&priv->gc);
+	if (ret) {
+		dev_err(&pdev->dev,
+			"failed to register X-Gene GPIO Standby driver\n");
+		if (priv->irq_domain)
+			irq_domain_remove(priv->irq_domain);
+		return ret;
 	}
 
+	dev_info(&pdev->dev, "X-Gene GPIO Standby driver registered\n");
+
+	/* Register interrupt handlers for gpio signaled acpi events */
+	acpi_gpiochip_request_interrupts(&priv->gc);
+
 	return ret;
 }
 
@@ -134,28 +369,14 @@ static int xgene_gpio_sb_remove(struct platform_device *pdev)
 {
 	struct xgene_gpio_sb *priv = platform_get_drvdata(pdev);
 
-	if (priv->nirq > 0) {
-		acpi_gpiochip_free_interrupts(&priv->gc);
-	}
+	acpi_gpiochip_free_interrupts(&priv->gc);
+
+	irq_domain_remove(priv->irq_domain);
 
 	gpiochip_remove(&priv->gc);
 	return 0;
 }
 
-static const struct of_device_id xgene_gpio_sb_of_match[] = {
-	{.compatible = "apm,xgene-gpio-sb", },
-	{},
-};
-MODULE_DEVICE_TABLE(of, xgene_gpio_sb_of_match);
-
-#ifdef CONFIG_ACPI
-static const struct acpi_device_id xgene_gpio_sb_acpi_match[] = {
-	{"APMC0D15", 0},
-	{},
-};
-MODULE_DEVICE_TABLE(acpi, xgene_gpio_sb_acpi_match);
-#endif
-
 static struct platform_driver xgene_gpio_sb_driver = {
 	.driver = {
 		   .name = "xgene-gpio-sb",
-- 
1.7.12.4

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