Date:   Thu, 15 Jun 2017 18:18:00 +0200
From:   Jerome Brunet <jbrunet@...libre.com>
To:     Marc Zyngier <marc.zyngier@....com>,
        Jason Cooper <jason@...edaemon.net>,
        Thomas Gleixner <tglx@...utronix.de>,
        Kevin Hilman <khilman@...libre.com>
Cc:     Jerome Brunet <jbrunet@...libre.com>,
        Carlo Caione <carlo@...one.org>,
        linux-amlogic@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v3 2/6] irqchip: meson: add support for gpio interrupt controller

Add support for the interrupt gpio controller found on Amlogic's meson
SoC family.

Unlike what the IP name suggest, it is not directly linked to the gpio
subsystem. This separate controller is able to spy on the SoC pad. It is
essentially a 256 to 8 router with a filtering block to select level or
edge and polarity. The number of actual mappable inputs depends on the
SoC.

Signed-off-by: Jerome Brunet <jbrunet@...libre.com>
---
 drivers/irqchip/Kconfig          |   8 +
 drivers/irqchip/Makefile         |   1 +
 drivers/irqchip/irq-meson-gpio.c | 407 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 416 insertions(+)
 create mode 100644 drivers/irqchip/irq-meson-gpio.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 478f8ace2664..be577a7512cc 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -301,3 +301,11 @@ config QCOM_IRQ_COMBINER
 	help
 	  Say yes here to add support for the IRQ combiner devices embedded
 	  in Qualcomm Technologies chips.
+
+config MESON_IRQ_GPIO
+       bool "Meson GPIO Interrupt Multiplexer"
+       depends on ARCH_MESON || COMPILE_TEST
+       select IRQ_DOMAIN
+       select IRQ_DOMAIN_HIERARCHY
+       help
+         Support Meson SoC Family GPIO Interrupt Multiplexer
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index b64c59b838a0..95bf2715850e 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -76,3 +76,4 @@ obj-$(CONFIG_EZNPS_GIC)			+= irq-eznps.o
 obj-$(CONFIG_ARCH_ASPEED)		+= irq-aspeed-vic.o
 obj-$(CONFIG_STM32_EXTI) 		+= irq-stm32-exti.o
 obj-$(CONFIG_QCOM_IRQ_COMBINER)		+= qcom-irq-combiner.o
+obj-$(CONFIG_MESON_IRQ_GPIO)		+= irq-meson-gpio.o
diff --git a/drivers/irqchip/irq-meson-gpio.c b/drivers/irqchip/irq-meson-gpio.c
new file mode 100644
index 000000000000..3b6d0ffec357
--- /dev/null
+++ b/drivers/irqchip/irq-meson-gpio.c
@@ -0,0 +1,407 @@
+/*
+ * Copyright (c) 2015 Endless Mobile, Inc.
+ * Author: Carlo Caione <carlo@...lessm.com>
+ * Copyright (c) 2016 BayLibre, SAS.
+ * Author: Jerome Brunet <jbrunet@...libre.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ * The full GNU General Public License is included in this distribution
+ * in the file called COPYING.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/irqchip.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#define NUM_UPSTREAM_IRQ 8
+#define MAX_INPUT_MUX 256
+
+#define REG_EDGE_POL	0x00
+#define REG_PIN_03_SEL	0x04
+#define REG_PIN_47_SEL	0x08
+#define REG_FILTER_SEL	0x0c
+
+#define REG_EDGE_POL_MASK(x)	(BIT(x) | BIT(16 + (x)))
+#define REG_EDGE_POL_EDGE(x)	BIT(x)
+#define REG_EDGE_POL_LOW(x)	BIT(16 + (x))
+#define REG_PIN_SEL_SHIFT(x)	(((x) % 4) * 8)
+#define REG_FILTER_SEL_SHIFT(x)	((x) * 4)
+
+struct meson_gpio_irq_params {
+	unsigned int nr_hwirq;
+};
+
+static const struct meson_gpio_irq_params meson8b_params = {
+	.nr_hwirq = 119,
+};
+
+static const struct meson_gpio_irq_params gxbb_params = {
+	.nr_hwirq = 133,
+};
+
+static const struct meson_gpio_irq_params gxl_params = {
+	.nr_hwirq = 110,
+};
+
+static const struct of_device_id meson_irq_gpio_matches[] = {
+	{ .compatible = "amlogic,meson8b-gpio-intc", .data = &meson8b_params },
+	{ .compatible = "amlogic,meson-gxbb-gpio-intc", .data = &gxbb_params },
+	{ .compatible = "amlogic,meson-gxl-gpio-intc", .data = &gxl_params },
+	{ }
+};
+
+struct meson_gpio_irq_controller {
+	unsigned int nr_hwirq;
+	void __iomem *base;
+	u32 upstream_irq[NUM_UPSTREAM_IRQ];
+	DECLARE_BITMAP(map, NUM_UPSTREAM_IRQ);
+	spinlock_t lock;
+};
+
+static void meson_gpio_irq_update_bits(struct meson_gpio_irq_controller *ctl,
+				       unsigned int reg, u32 mask, u32 val)
+{
+	u32 tmp;
+
+	tmp = readl_relaxed(ctl->base + reg);
+	tmp &= ~mask;
+	tmp |= val;
+	writel_relaxed(tmp, ctl->base + reg);
+}
+
+static int
+meson_gpio_irq_request_channel(struct meson_gpio_irq_controller *ctl,
+			       unsigned long  hwirq,
+			       u32 **parent_hwirq)
+{
+	unsigned int reg, channel;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ctl->lock, flags);
+
+	/* Find a free channel */
+	channel = find_first_zero_bit(ctl->map, NUM_UPSTREAM_IRQ);
+	if (channel >= NUM_UPSTREAM_IRQ) {
+		spin_unlock_irqrestore(&ctl->lock, flags);
+		pr_err("No channel available\n");
+		return -ENOSPC;
+	}
+
+	/* Mark the channel as used */
+	set_bit(channel, ctl->map);
+
+	/*
+	 * Setup the mux of the channel to route the signal of the pad
+	 * to the appropriate input of the GIC
+	 */
+	reg = (channel < 4) ? REG_PIN_03_SEL : REG_PIN_47_SEL;
+	meson_gpio_irq_update_bits(ctl, reg,
+				   0xff << REG_PIN_SEL_SHIFT(channel),
+				   hwirq << REG_PIN_SEL_SHIFT(channel));
+
+	/* Get the parent hwirq number assigned to this channel */
+	*parent_hwirq = &(ctl->upstream_irq[channel]);
+
+	spin_unlock_irqrestore(&ctl->lock, flags);
+
+	pr_debug("hwirq %lu assigned to channel %d - parent %u\n",
+		 hwirq, channel, **parent_hwirq);
+
+	return 0;
+}
+
+static unsigned int
+meson_gpio_irq_get_channel(struct meson_gpio_irq_controller *ctl,
+			   u32 *parent_hwirq)
+{
+	return parent_hwirq - ctl->upstream_irq;
+}
+
+static void
+meson_gpio_irq_release_channel(struct meson_gpio_irq_controller *ctl,
+			       u32 *parent_hwirq)
+{
+	unsigned int channel;
+
+	channel = meson_gpio_irq_get_channel(ctl, parent_hwirq);
+	clear_bit(channel, ctl->map);
+}
+
+static int meson_gpio_irq_type_setup(struct meson_gpio_irq_controller *ctl,
+				     unsigned int type,
+				     u32 *parent_hwirq)
+{
+	u32 val = 0;
+	unsigned int channel;
+	unsigned long flags;
+
+	channel = meson_gpio_irq_get_channel(ctl, parent_hwirq);
+
+	/*
+	 * The controller has a filter block to operate in either LEVEL or
+	 * EDGE mode, then signal is sent to the GIC. To enable LEVEL_LOW and
+	 * EDGE_FALLING support (which the GIC does not support), the filter
+	 * block is also able to invert the input signal it gets before
+	 * providing it to the GIC.
+	 */
+	type &= IRQ_TYPE_SENSE_MASK;
+
+	if (type == IRQ_TYPE_EDGE_BOTH)
+		return -EINVAL;
+
+	if (type & (IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING))
+		val |= REG_EDGE_POL_EDGE(channel);
+
+	if (type & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_EDGE_FALLING))
+		val |= REG_EDGE_POL_LOW(channel);
+
+	spin_lock_irqsave(&ctl->lock, flags);
+
+	meson_gpio_irq_update_bits(ctl, REG_EDGE_POL,
+				   REG_EDGE_POL_MASK(channel), val);
+
+	spin_unlock_irqrestore(&ctl->lock, flags);
+
+	return 0;
+}
+
+static unsigned int meson_gpio_irq_type_output(unsigned int type)
+{
+	unsigned int sense = type & IRQ_TYPE_SENSE_MASK;
+
+	type &= ~IRQ_TYPE_SENSE_MASK;
+
+	/*
+	 * The polarity of the signal provided to the GIC should always
+	 * be high.
+	 */
+	if (sense & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW))
+		type |= IRQ_TYPE_LEVEL_HIGH;
+	else if (sense & (IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING))
+		type |= IRQ_TYPE_EDGE_RISING;
+
+	return type;
+}
+
+static int meson_gpio_irq_set_type(struct irq_data *data, unsigned int type)
+{
+	struct meson_gpio_irq_controller *ctl = data->domain->host_data;
+	u32 *parent_hwirq = irq_data_get_irq_chip_data(data);
+	int ret;
+
+	ret = meson_gpio_irq_type_setup(ctl, type, parent_hwirq);
+	if (ret)
+		return ret;
+
+	return irq_chip_set_type_parent(data,
+					meson_gpio_irq_type_output(type));
+}
+
+static struct irq_chip meson_gpio_irq_chip = {
+	.name			= "meson-gpio-irqchip",
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_set_type		= meson_gpio_irq_set_type,
+	.irq_retrigger		= irq_chip_retrigger_hierarchy,
+#ifdef CONFIG_SMP
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+#endif
+	.flags			= IRQCHIP_SET_TYPE_MASKED,
+};
+
+static int meson_gpio_irq_domain_translate(struct irq_domain *domain,
+					   struct irq_fwspec *fwspec,
+					   unsigned long *hwirq,
+					   unsigned int *type)
+{
+	if (is_of_node(fwspec->fwnode) && fwspec->param_count == 2) {
+		*hwirq	= fwspec->param[0];
+		*type	= fwspec->param[1];
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int meson_gpio_irq_allocate_gic_irq(struct irq_domain *domain,
+					   unsigned int virq,
+					   u32 hwirq,
+					   unsigned int type)
+{
+	struct irq_fwspec fwspec;
+
+	fwspec.fwnode = domain->parent->fwnode;
+	fwspec.param_count = 3;
+	fwspec.param[0] = 0;	/* SPI */
+	fwspec.param[1] = hwirq;
+	fwspec.param[2] = meson_gpio_irq_type_output(type);
+
+	return irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
+}
+
+static int meson_gpio_irq_domain_alloc(struct irq_domain *domain,
+				       unsigned int virq,
+				       unsigned int nr_irqs,
+				       void *data)
+{
+	struct irq_fwspec *fwspec = data;
+	struct meson_gpio_irq_controller *ctl = domain->host_data;
+	unsigned long hwirq;
+	u32 *parent_hwirq;
+	unsigned int type;
+	int ret;
+
+	if (WARN_ON(nr_irqs != 1))
+		return -EINVAL;
+
+	ret = meson_gpio_irq_domain_translate(domain, fwspec, &hwirq, &type);
+	if (ret)
+		return ret;
+
+	ret = meson_gpio_irq_request_channel(ctl, hwirq, &parent_hwirq);
+	if (ret)
+		return ret;
+
+	ret = meson_gpio_irq_allocate_gic_irq(domain, virq,
+					      *parent_hwirq, type);
+	if (ret < 0) {
+		pr_err("failed to allocate gic irq %u\n", *parent_hwirq);
+		return ret;
+	}
+
+	irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
+				      &meson_gpio_irq_chip, parent_hwirq);
+
+	return 0;
+}
+
+static void meson_gpio_irq_domain_free(struct irq_domain *domain,
+				       unsigned int virq,
+				       unsigned int nr_irqs)
+{
+	struct meson_gpio_irq_controller *ctl = domain->host_data;
+	struct irq_data *irq_data;
+	u32 *parent_hwirq;
+
+	if (WARN_ON(nr_irqs != 1))
+		return;
+
+	irq_domain_free_irqs_parent(domain, virq, 1);
+
+	irq_data = irq_domain_get_irq_data(domain, virq);
+	parent_hwirq = irq_data_get_irq_chip_data(irq_data);
+
+	meson_gpio_irq_release_channel(ctl, parent_hwirq);
+}
+
+static const struct irq_domain_ops meson_gpio_irq_domain_ops = {
+	.alloc		= meson_gpio_irq_domain_alloc,
+	.free		= meson_gpio_irq_domain_free,
+	.translate	= meson_gpio_irq_domain_translate,
+};
+
+static int __init meson_gpio_irq_parse_dt(struct device_node *node,
+					  struct meson_gpio_irq_controller *ctl)
+{
+	const struct of_device_id *match;
+	const struct meson_gpio_irq_params *params;
+	int ret;
+
+	match = of_match_node(meson_irq_gpio_matches, node);
+	if (!match)
+		return -ENODEV;
+
+	params = match->data;
+	ctl->nr_hwirq = params->nr_hwirq;
+
+	ret = of_property_read_variable_u32_array(node,
+						  "amlogic,upstream-interrupts",
+						  ctl->upstream_irq,
+						  NUM_UPSTREAM_IRQ,
+						  NUM_UPSTREAM_IRQ);
+	if (ret < 0) {
+		pr_err("can't get %d upstream interrupts\n", NUM_UPSTREAM_IRQ);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int __init meson_gpio_irq_of_init(struct device_node *node,
+					 struct device_node *parent)
+{
+	struct irq_domain *domain, *parent_domain;
+	struct meson_gpio_irq_controller *ctl;
+	int ret;
+
+	if (!parent) {
+		pr_err("missing parent interrupt node\n");
+		return -ENODEV;
+	}
+
+	parent_domain = irq_find_host(parent);
+	if (!parent_domain) {
+		pr_err("unable to obtain parent domain\n");
+		return -ENXIO;
+	}
+
+	ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
+	if (!ctl)
+		return -ENOMEM;
+
+	spin_lock_init(&ctl->lock);
+
+	ctl->base = of_iomap(node, 0);
+	if (!ctl->base) {
+		ret = -ENOMEM;
+		goto free_ctl;
+	}
+
+	bitmap_zero(ctl->map, NUM_UPSTREAM_IRQ);
+
+	ret = meson_gpio_irq_parse_dt(node, ctl);
+	if (ret)
+		goto free_upstream_irq;
+
+	domain = irq_domain_create_hierarchy(parent_domain, 0, ctl->nr_hwirq,
+					     of_node_to_fwnode(node),
+					     &meson_gpio_irq_domain_ops,
+					     ctl);
+	if (!domain) {
+		pr_err("failed to add domain\n");
+		ret = -ENODEV;
+		goto free_upstream_irq;
+	}
+
+	pr_info("%d to %d gpio interrupt mux initialized\n",
+		ctl->nr_hwirq, NUM_UPSTREAM_IRQ);
+
+	return 0;
+
+free_upstream_irq:
+	iounmap(ctl->base);
+free_ctl:
+	kfree(ctl);
+
+	return ret;
+}
+
+IRQCHIP_DECLARE(meson_gpio_intc, "amlogic,meson-gpio-intc",
+		meson_gpio_irq_of_init);
-- 
2.9.4

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