[PATCH v3 2/2] irqchip: add driver for imx-irqsteer controller

[Lucas Stach]

The irqsteer block is a interrupt multiplexer/remapper found on the
i.MX8 line of SoCs.

Signed-off-by: Fugang Duan <fugang.duan@xxxxxxx>
Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
---
v2:
 - use raw_spinlock
 - add proper clk error handling
 - align register offset calculation with reality
 - use correct SPDX identifier
 - simplify DT configuration
v3:
 - switch to onecell IRQ handle
 - fix channel register save/restore in PM calls
---
 drivers/irqchip/Kconfig            |   8 +
 drivers/irqchip/Makefile           |   1 +
 drivers/irqchip/irq-imx-irqsteer.c | 261 +++++++++++++++++++++++++++++
 3 files changed, 270 insertions(+)
 create mode 100644 drivers/irqchip/irq-imx-irqsteer.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 51a5ef0e96ed..25607a002bf1 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -391,6 +391,14 @@ config CSKY_APB_INTC
 	  by C-SKY single core SOC system. It use mmio map apb-bus to visit
 	  the controller's register.
 
+config IMX_IRQSTEER
+	bool "i.MX IRQSTEER support"
+	depends on ARCH_MXC || COMPILE_TEST
+	default ARCH_MXC
+	select IRQ_DOMAIN
+	help
+	  Support for the i.MX IRQSTEER interrupt multiplexer/remapper.
+
 endmenu
 
 config SIFIVE_PLIC
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 794c13d3ac3d..8ef99b3f7e4e 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -91,3 +91,4 @@ obj-$(CONFIG_QCOM_PDC)			+= qcom-pdc.o
 obj-$(CONFIG_CSKY_MPINTC)		+= irq-csky-mpintc.o
 obj-$(CONFIG_CSKY_APB_INTC)		+= irq-csky-apb-intc.o
 obj-$(CONFIG_SIFIVE_PLIC)		+= irq-sifive-plic.o
+obj-$(CONFIG_IMX_IRQSTEER)		+= irq-imx-irqsteer.o
diff --git a/drivers/irqchip/irq-imx-irqsteer.c b/drivers/irqchip/irq-imx-irqsteer.c
new file mode 100644
index 000000000000..5b3f1d735685
--- /dev/null
+++ b/drivers/irqchip/irq-imx-irqsteer.c
@@ -0,0 +1,261 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2017 NXP
+ * Copyright (C) 2018 Pengutronix, Lucas Stach <kernel@xxxxxxxxxxxxxx>
+ */
+
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/of_platform.h>
+#include <linux/spinlock.h>
+
+#define CTRL_STRIDE_OFF(_t, _r)	(_t * 8 * _r)
+#define CHANCTRL		0x0
+#define CHANMASK(n, t)		(CTRL_STRIDE_OFF(t, 0) + 0x4 * (n) + 0x4)
+#define CHANSET(n, t)		(CTRL_STRIDE_OFF(t, 1) + 0x4 * (n) + 0x4)
+#define CHANSTATUS(n, t)	(CTRL_STRIDE_OFF(t, 2) + 0x4 * (n) + 0x4)
+#define CHAN_MINTDIS(t)		(CTRL_STRIDE_OFF(t, 3) + 0x4)
+#define CHAN_MASTRSTAT(t)	(CTRL_STRIDE_OFF(t, 3) + 0x8)
+
+struct irqsteer_data {
+	void __iomem		*regs;
+	struct clk		*ipg_clk;
+	int			irq;
+	raw_spinlock_t		lock;
+	int			irq_groups;
+	int			channel;
+	struct irq_domain	*domain;
+	u32			*saved_reg;
+};
+
+static int imx_irqsteer_get_reg_index(struct irqsteer_data *data,
+				      unsigned long irqnum)
+{
+	return (data->irq_groups * 2 - irqnum / 32 - 1);
+}
+
+static void imx_irqsteer_irq_unmask(struct irq_data *d)
+{
+	struct irqsteer_data *data = d->chip_data;
+	int idx = imx_irqsteer_get_reg_index(data, d->hwirq);
+	unsigned long flags;
+	u32 val;
+
+	raw_spin_lock_irqsave(&data->lock, flags);
+	val = readl_relaxed(data->regs + CHANMASK(idx, data->irq_groups));
+	val |= BIT(d->hwirq % 32);
+	writel_relaxed(val, data->regs + CHANMASK(idx, data->irq_groups));
+	raw_spin_unlock_irqrestore(&data->lock, flags);
+}
+
+static void imx_irqsteer_irq_mask(struct irq_data *d)
+{
+	struct irqsteer_data *data = d->chip_data;
+	int idx = imx_irqsteer_get_reg_index(data, d->hwirq);
+	unsigned long flags;
+	u32 val;
+
+	raw_spin_lock_irqsave(&data->lock, flags);
+	val = readl_relaxed(data->regs + CHANMASK(idx, data->irq_groups));
+	val &= ~BIT(d->hwirq % 32);
+	writel_relaxed(val, data->regs + CHANMASK(idx, data->irq_groups));
+	raw_spin_unlock_irqrestore(&data->lock, flags);
+}
+
+static struct irq_chip imx_irqsteer_irq_chip = {
+	.name		= "irqsteer",
+	.irq_mask	= imx_irqsteer_irq_mask,
+	.irq_unmask	= imx_irqsteer_irq_unmask,
+};
+
+static int imx_irqsteer_irq_map(struct irq_domain *h, unsigned int irq,
+				irq_hw_number_t hwirq)
+{
+	irq_set_status_flags(irq, IRQ_LEVEL);
+	irq_set_chip_data(irq, h->host_data);
+	irq_set_chip_and_handler(irq, &imx_irqsteer_irq_chip, handle_level_irq);
+
+	return 0;
+}
+
+static const struct irq_domain_ops imx_irqsteer_domain_ops = {
+	.map		= imx_irqsteer_irq_map,
+	.xlate		= irq_domain_xlate_onecell,
+};
+
+static void imx_irqsteer_irq_handler(struct irq_desc *desc)
+{
+	struct irqsteer_data *data = irq_desc_get_handler_data(desc);
+	int i;
+
+	chained_irq_enter(irq_desc_get_chip(desc), desc);
+
+	for (i = 0; i < data->irq_groups * 64; i += 32) {
+		int idx = imx_irqsteer_get_reg_index(data, i);
+		unsigned long irqmap;
+		int pos, virq;
+
+		irqmap = readl_relaxed(data->regs +
+				       CHANSTATUS(idx, data->irq_groups));
+
+		for_each_set_bit(pos, &irqmap, 32) {
+			virq = irq_find_mapping(data->domain, pos + i);
+			if (virq)
+				generic_handle_irq(virq);
+		}
+	}
+
+	chained_irq_exit(irq_desc_get_chip(desc), desc);
+}
+
+static int imx_irqsteer_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct irqsteer_data *data;
+	struct resource *res;
+	int ret;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	data->regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(data->regs)) {
+		dev_err(&pdev->dev, "failed to initialize reg\n");
+		return PTR_ERR(data->regs);
+	}
+
+	data->irq = platform_get_irq(pdev, 0);
+	if (data->irq <= 0) {
+		dev_err(&pdev->dev, "failed to get irq\n");
+		return -ENODEV;
+	}
+
+	data->ipg_clk = devm_clk_get(&pdev->dev, "ipg");
+	if (IS_ERR(data->ipg_clk)) {
+		ret = PTR_ERR(data->ipg_clk);
+		if (ret != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "failed to get ipg clk: %d\n", ret);
+		return ret;
+	}
+
+	raw_spin_lock_init(&data->lock);
+
+	of_property_read_u32(np, "fsl,irq-groups", &data->irq_groups);
+	of_property_read_u32(np, "fsl,channel", &data->channel);
+
+	if (IS_ENABLED(CONFIG_PM_SLEEP)) {
+		data->saved_reg = devm_kzalloc(&pdev->dev,
+					sizeof(u32) * data->irq_groups * 2,
+					GFP_KERNEL);
+		if (!data->saved_reg)
+			return -ENOMEM;
+	}
+
+	ret = clk_prepare_enable(data->ipg_clk);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to enable ipg clk: %d\n", ret);
+		return ret;
+	}
+
+	/* steer all IRQs into configured channel */
+	writel_relaxed(BIT(data->channel), data->regs + CHANCTRL);
+
+	data->domain = irq_domain_add_linear(np, data->irq_groups * 64,
+					     &imx_irqsteer_domain_ops, data);
+	if (!data->domain) {
+		dev_err(&pdev->dev, "failed to create IRQ domain\n");
+		clk_disable_unprepare(data->ipg_clk);
+		return -ENOMEM;
+	}
+
+	irq_set_chained_handler_and_data(data->irq, imx_irqsteer_irq_handler,
+					 data);
+
+	platform_set_drvdata(pdev, data);
+
+	return 0;
+}
+
+static int imx_irqsteer_remove(struct platform_device *pdev)
+{
+	struct irqsteer_data *irqsteer_data = platform_get_drvdata(pdev);
+
+	irq_set_chained_handler_and_data(irqsteer_data->irq, NULL, NULL);
+	irq_domain_remove(irqsteer_data->domain);
+
+	clk_disable_unprepare(irqsteer_data->ipg_clk);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static void imx_irqsteer_save_regs(struct irqsteer_data *data)
+{
+	int i;
+
+	for (i = 0; i < data->irq_groups * 2; i++)
+		data->saved_reg[i] = readl_relaxed(data->regs +
+						CHANMASK(i, data->irq_groups));
+}
+
+static void imx_irqsteer_restore_regs(struct irqsteer_data *data)
+{
+	int i;
+
+	writel_relaxed(BIT(data->channel), data->regs + CHANCTRL);
+	for (i = 0; i < data->irq_groups * 2; i++)
+		writel_relaxed(data->saved_reg[i],
+			       data->regs + CHANMASK(i, data->irq_groups));
+}
+
+static int imx_irqsteer_suspend(struct device *dev)
+{
+	struct irqsteer_data *irqsteer_data = dev_get_drvdata(dev);
+
+	imx_irqsteer_save_regs(irqsteer_data);
+	clk_disable_unprepare(irqsteer_data->ipg_clk);
+
+	return 0;
+}
+
+static int imx_irqsteer_resume(struct device *dev)
+{
+	struct irqsteer_data *irqsteer_data = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_prepare_enable(irqsteer_data->ipg_clk);
+	if (ret) {
+		dev_err(dev, "failed to enable ipg clk: %d\n", ret);
+		return ret;
+	}
+	imx_irqsteer_restore_regs(irqsteer_data);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops imx_irqsteer_pm_ops = {
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx_irqsteer_suspend, imx_irqsteer_resume)
+};
+
+static const struct of_device_id imx_irqsteer_dt_ids[] = {
+	{ .compatible = "fsl,imx-irqsteer", },
+	{},
+};
+
+static struct platform_driver imx_irqsteer_driver = {
+	.driver = {
+		.name = "imx-irqsteer",
+		.of_match_table = imx_irqsteer_dt_ids,
+		.pm = &imx_irqsteer_pm_ops,
+	},
+	.probe = imx_irqsteer_probe,
+	.remove = imx_irqsteer_remove,
+};
+builtin_platform_driver(imx_irqsteer_driver);
-- 
2.19.1