irqchip/mvebu-pic: New driver for Marvell Armada 7K/8K PIC

The Marvell Armada 7K/8K integrates a secondary interrupt controller
very originally named "PIC". It is connected to the main GIC via a
PPI. Amongst other things, this PIC is used for the ARM PMU.

This commit adds a simple irqchip driver for this interrupt
controller. Since this interrupt controller is not needed early at boot
time, we make the driver a proper platform driver rather than use the
IRQCHIP_DECLARE() mechanism.

Signed-off-by: Yehuda Yitschak <yehuday@marvell.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Link: https://lkml.kernel.org/r/1470408921-447-3-git-send-email-thomas.petazzoni@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

drivers/irqchip/Kconfig

@@ -251,6 +251,9 @@ config IRQ_MXS
 config MVEBU_ODMI
 	bool
 
+config MVEBU_PIC
+	bool
+
 config LS_SCFG_MSI
 	def_bool y if SOC_LS1021A || ARCH_LAYERSCAPE
 	depends on PCI && PCI_MSI

drivers/irqchip/Makefile

@@ -68,6 +68,7 @@ obj-$(CONFIG_INGENIC_IRQ)		+= irq-ingenic.o
 obj-$(CONFIG_IMX_GPCV2)			+= irq-imx-gpcv2.o
 obj-$(CONFIG_PIC32_EVIC)		+= irq-pic32-evic.o
 obj-$(CONFIG_MVEBU_ODMI)		+= irq-mvebu-odmi.o
+obj-$(CONFIG_MVEBU_PIC)			+= irq-mvebu-pic.o
 obj-$(CONFIG_LS_SCFG_MSI)		+= irq-ls-scfg-msi.o
 obj-$(CONFIG_EZNPS_GIC)			+= irq-eznps.o
 obj-$(CONFIG_ARCH_ASPEED)		+= irq-aspeed-vic.o

drivers/irqchip/irq-mvebu-pic.c

@@ -0,0 +1,197 @@
+/*
+ * Copyright (C) 2016 Marvell
+ *
+ * Yehuda Yitschak <yehuday@marvell.com>
+ * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+
+#define PIC_CAUSE	       0x0
+#define PIC_MASK	       0x4
+
+#define PIC_MAX_IRQS		32
+#define PIC_MAX_IRQ_MASK	((1UL << PIC_MAX_IRQS) - 1)
+
+struct mvebu_pic {
+	void __iomem *base;
+	u32 parent_irq;
+	struct irq_domain *domain;
+	struct irq_chip irq_chip;
+};
+
+static void mvebu_pic_reset(struct mvebu_pic *pic)
+{
+	/* ACK and mask all interrupts */
+	writel(0, pic->base + PIC_MASK);
+	writel(PIC_MAX_IRQ_MASK, pic->base + PIC_CAUSE);
+}
+
+static void mvebu_pic_eoi_irq(struct irq_data *d)
+{
+	struct mvebu_pic *pic = irq_data_get_irq_chip_data(d);
+
+	writel(1 << d->hwirq, pic->base + PIC_CAUSE);
+}
+
+static void mvebu_pic_mask_irq(struct irq_data *d)
+{
+	struct mvebu_pic *pic = irq_data_get_irq_chip_data(d);
+	u32 reg;
+
+	reg =  readl(pic->base + PIC_MASK);
+	reg |= (1 << d->hwirq);
+	writel(reg, pic->base + PIC_MASK);
+}
+
+static void mvebu_pic_unmask_irq(struct irq_data *d)
+{
+	struct mvebu_pic *pic = irq_data_get_irq_chip_data(d);
+	u32 reg;
+
+	reg = readl(pic->base + PIC_MASK);
+	reg &= ~(1 << d->hwirq);
+	writel(reg, pic->base + PIC_MASK);
+}
+
+static int mvebu_pic_irq_map(struct irq_domain *domain, unsigned int virq,
+			     irq_hw_number_t hwirq)
+{
+	struct mvebu_pic *pic = domain->host_data;
+
+	irq_set_percpu_devid(virq);
+	irq_set_chip_data(virq, pic);
+	irq_set_chip_and_handler(virq, &pic->irq_chip,
+				 handle_percpu_devid_irq);
+	irq_set_status_flags(virq, IRQ_LEVEL);
+	irq_set_probe(virq);
+
+	return 0;
+}
+
+static const struct irq_domain_ops mvebu_pic_domain_ops = {
+	.map = mvebu_pic_irq_map,
+	.xlate = irq_domain_xlate_onecell,
+};
+
+static void mvebu_pic_handle_cascade_irq(struct irq_desc *desc)
+{
+	struct mvebu_pic *pic = irq_desc_get_handler_data(desc);
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	unsigned long irqmap, irqn;
+	unsigned int cascade_irq;
+
+	irqmap = readl_relaxed(pic->base + PIC_CAUSE);
+	chained_irq_enter(chip, desc);
+
+	for_each_set_bit(irqn, &irqmap, BITS_PER_LONG) {
+		cascade_irq = irq_find_mapping(pic->domain, irqn);
+		generic_handle_irq(cascade_irq);
+	}
+
+	chained_irq_exit(chip, desc);
+}
+
+static void mvebu_pic_enable_percpu_irq(void *data)
+{
+	struct mvebu_pic *pic = data;
+
+	mvebu_pic_reset(pic);
+	enable_percpu_irq(pic->parent_irq, IRQ_TYPE_NONE);
+}
+
+static void mvebu_pic_disable_percpu_irq(void *data)
+{
+	struct mvebu_pic *pic = data;
+
+	disable_percpu_irq(pic->parent_irq);
+}
+
+static int mvebu_pic_probe(struct platform_device *pdev)
+{
+	struct device_node *node = pdev->dev.of_node;
+	struct mvebu_pic *pic;
+	struct irq_chip *irq_chip;
+	struct resource *res;
+
+	pic = devm_kzalloc(&pdev->dev, sizeof(struct mvebu_pic), GFP_KERNEL);
+	if (!pic)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	pic->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(pic->base))
+		return PTR_ERR(pic->base);
+
+	irq_chip = &pic->irq_chip;
+	irq_chip->name = dev_name(&pdev->dev);
+	irq_chip->irq_mask = mvebu_pic_mask_irq;
+	irq_chip->irq_unmask = mvebu_pic_unmask_irq;
+	irq_chip->irq_eoi = mvebu_pic_eoi_irq;
+
+	pic->parent_irq = irq_of_parse_and_map(node, 0);
+	if (pic->parent_irq <= 0) {
+		dev_err(&pdev->dev, "Failed to parse parent interrupt\n");
+		return -EINVAL;
+	}
+
+	pic->domain = irq_domain_add_linear(node, PIC_MAX_IRQS,
+					    &mvebu_pic_domain_ops, pic);
+	if (!pic->domain) {
+		dev_err(&pdev->dev, "Failed to allocate irq domain\n");
+		return -ENOMEM;
+	}
+
+	irq_set_chained_handler(pic->parent_irq, mvebu_pic_handle_cascade_irq);
+	irq_set_handler_data(pic->parent_irq, pic);
+
+	on_each_cpu(mvebu_pic_enable_percpu_irq, pic, 1);
+
+	platform_set_drvdata(pdev, pic);
+
+	return 0;
+}
+
+static int mvebu_pic_remove(struct platform_device *pdev)
+{
+	struct mvebu_pic *pic = platform_get_drvdata(pdev);
+
+	on_each_cpu(mvebu_pic_disable_percpu_irq, pic, 1);
+	irq_domain_remove(pic->domain);
+
+	return 0;
+}
+
+static const struct of_device_id mvebu_pic_of_match[] = {
+	{ .compatible = "marvell,armada-8k-pic", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mvebu_pic_of_match);
+
+static struct platform_driver mvebu_pic_driver = {
+	.probe  = mvebu_pic_probe,
+	.remove = mvebu_pic_remove,
+	.driver = {
+		.name = "mvebu-pic",
+		.of_match_table = mvebu_pic_of_match,
+	},
+};
+module_platform_driver(mvebu_pic_driver);
+
+MODULE_AUTHOR("Yehuda Yitschak <yehuday@marvell.com>");
+MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:mvebu_pic");
+