irqchip/meson: Add support for gpio interrupt controller

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

This controller is a separate controller from the gpio controller. It 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.

Cc: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

3 files changed, 423 insertions, 0 deletions

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 77df38ed0050..1cb39405d7f8 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -324,4 +324,12 @@ config IRQ_UNIPHIER_AIDET
 	help
 	  Support for the UniPhier AIDET (ARM Interrupt Detector).
 
+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
+
 endmenu
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 845abc107ad5..065adf4102c9 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -79,3 +79,4 @@ obj-$(CONFIG_ARCH_ASPEED)		+= irq-aspeed-vic.o irq-aspeed-i2c-ic.o
 obj-$(CONFIG_STM32_EXTI) 		+= irq-stm32-exti.o
 obj-$(CONFIG_QCOM_IRQ_COMBINER)		+= qcom-irq-combiner.o
 obj-$(CONFIG_IRQ_UNIPHIER_AIDET)	+= irq-uniphier-aidet.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..c7cc7e37a23c
--- /dev/null
+++ b/drivers/irqchip/irq-meson-gpio.c
@@ -0,0 +1,414 @@
+/*
+ * Copyright (c) 2015 Endless Mobile, Inc.
+ * Author: Carlo Caione <carlo@endlessm.com>
+ * Copyright (c) 2016 BayLibre, SAS.
+ * Author: Jerome Brunet <jbrunet@baylibre.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_CHANNEL 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 channel_irqs[NUM_CHANNEL];
+	DECLARE_BITMAP(channel_map, NUM_CHANNEL);
+	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 unsigned int meson_gpio_irq_channel_to_reg(unsigned int channel)
+{
+	return (channel < 4) ? REG_PIN_03_SEL : REG_PIN_47_SEL;
+}
+
+static int
+meson_gpio_irq_request_channel(struct meson_gpio_irq_controller *ctl,
+			       unsigned long  hwirq,
+			       u32 **channel_hwirq)
+{
+	unsigned int reg, idx;
+
+	spin_lock(&ctl->lock);
+
+	/* Find a free channel */
+	idx = find_first_zero_bit(ctl->channel_map, NUM_CHANNEL);
+	if (idx >= NUM_CHANNEL) {
+		spin_unlock(&ctl->lock);
+		pr_err("No channel available\n");
+		return -ENOSPC;
+	}
+
+	/* Mark the channel as used */
+	set_bit(idx, ctl->channel_map);
+
+	/*
+	 * Setup the mux of the channel to route the signal of the pad
+	 * to the appropriate input of the GIC
+	 */
+	reg = meson_gpio_irq_channel_to_reg(idx);
+	meson_gpio_irq_update_bits(ctl, reg,
+				   0xff << REG_PIN_SEL_SHIFT(idx),
+				   hwirq << REG_PIN_SEL_SHIFT(idx));
+
+	/*
+	 * Get the hwirq number assigned to this channel through
+	 * a pointer the channel_irq table. The added benifit of this
+	 * method is that we can also retrieve the channel index with
+	 * it, using the table base.
+	 */
+	*channel_hwirq = &(ctl->channel_irqs[idx]);
+
+	spin_unlock(&ctl->lock);
+
+	pr_debug("hwirq %lu assigned to channel %d - irq %u\n",
+		 hwirq, idx, **channel_hwirq);
+
+	return 0;
+}
+
+static unsigned int
+meson_gpio_irq_get_channel_idx(struct meson_gpio_irq_controller *ctl,
+			       u32 *channel_hwirq)
+{
+	return channel_hwirq - ctl->channel_irqs;
+}
+
+static void
+meson_gpio_irq_release_channel(struct meson_gpio_irq_controller *ctl,
+			       u32 *channel_hwirq)
+{
+	unsigned int idx;
+
+	idx = meson_gpio_irq_get_channel_idx(ctl, channel_hwirq);
+	clear_bit(idx, ctl->channel_map);
+}
+
+static int meson_gpio_irq_type_setup(struct meson_gpio_irq_controller *ctl,
+				     unsigned int type,
+				     u32 *channel_hwirq)
+{
+	u32 val = 0;
+	unsigned int idx;
+
+	idx = meson_gpio_irq_get_channel_idx(ctl, channel_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(idx);
+
+	if (type & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_EDGE_FALLING))
+		val |= REG_EDGE_POL_LOW(idx);
+
+	spin_lock(&ctl->lock);
+
+	meson_gpio_irq_update_bits(ctl, REG_EDGE_POL,
+				   REG_EDGE_POL_MASK(idx), val);
+
+	spin_unlock(&ctl->lock);
+
+	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 *channel_hwirq = irq_data_get_irq_chip_data(data);
+	int ret;
+
+	ret = meson_gpio_irq_type_setup(ctl, type, channel_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 *channel_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, &channel_hwirq);
+	if (ret)
+		return ret;
+
+	ret = meson_gpio_irq_allocate_gic_irq(domain, virq,
+					      *channel_hwirq, type);
+	if (ret < 0) {
+		pr_err("failed to allocate gic irq %u\n", *channel_hwirq);
+		meson_gpio_irq_release_channel(ctl, channel_hwirq);
+		return ret;
+	}
+
+	irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
+				      &meson_gpio_irq_chip, channel_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 *channel_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);
+	channel_hwirq = irq_data_get_irq_chip_data(irq_data);
+
+	meson_gpio_irq_release_channel(ctl, channel_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,channel-interrupts",
+						  ctl->channel_irqs,
+						  NUM_CHANNEL,
+						  NUM_CHANNEL);
+	if (ret < 0) {
+		pr_err("can't get %d channel interrupts\n", NUM_CHANNEL);
+		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;
+	}
+
+	ret = meson_gpio_irq_parse_dt(node, ctl);
+	if (ret)
+		goto free_channel_irqs;
+
+	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_channel_irqs;
+	}
+
+	pr_info("%d to %d gpio interrupt mux initialized\n",
+		ctl->nr_hwirq, NUM_CHANNEL);
+
+	return 0;
+
+free_channel_irqs:
+	iounmap(ctl->base);
+free_ctl:
+	kfree(ctl);
+
+	return ret;
+}
+
+IRQCHIP_DECLARE(meson_gpio_intc, "amlogic,meson-gpio-intc",
+		meson_gpio_irq_of_init);