[PATCH 02/16] irqchip: tegra: add DT-based support for legacy interrupt controller

[marc.zyngier@arm.com (Marc Zyngier)]

Tegra's LIC (Legacy Interrupt Controller) has been so far only
supported as a weird extension of the GIC, which is not exactly
pretty.

The stacked irq domain framework fits this pretty well, and allows
the LIC code to be turned into a standalone irqchip. In the process,
make the driver DT aware, something that was sorely missing from
the mach-tegra implementation.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/Makefile    |   1 +
 drivers/irqchip/irq-tegra.c | 335 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 336 insertions(+)
 create mode 100644 drivers/irqchip/irq-tegra.c

diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 983634d..0fd9c7d 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -6,6 +6,7 @@ obj-$(CONFIG_ARCH_HIP04)		+= irq-hip04.o
 obj-$(CONFIG_ARCH_MMP)			+= irq-mmp.o
 obj-$(CONFIG_ARCH_MVEBU)		+= irq-armada-370-xp.o
 obj-$(CONFIG_ARCH_MXS)			+= irq-mxs.o
+obj-$(CONFIG_ARCH_TEGRA)		+= irq-tegra.o
 obj-$(CONFIG_ARCH_S3C24XX)		+= irq-s3c24xx.o
 obj-$(CONFIG_DW_APB_ICTL)		+= irq-dw-apb-ictl.o
 obj-$(CONFIG_METAG)			+= irq-metag-ext.o
diff --git a/drivers/irqchip/irq-tegra.c b/drivers/irqchip/irq-tegra.c
new file mode 100644
index 0000000..b4fc2e3
--- /dev/null
+++ b/drivers/irqchip/irq-tegra.c
@@ -0,0 +1,335 @@
+/*
+ * Driver code for Tegra's Legacy Interrupt Controller
+ *
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * Heavily based on the original arch/arm/mach-tegra/irq.c code:
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * Author:
+ *	Colin Cross <ccross@android.com>
+ *
+ * Copyright (C) 2010,2013, NVIDIA Corporation
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+#include <linux/syscore_ops.h>
+
+#include "irqchip.h"
+
+#define ICTLR_CPU_IEP_VFIQ	0x08
+#define ICTLR_CPU_IEP_FIR	0x14
+#define ICTLR_CPU_IEP_FIR_SET	0x18
+#define ICTLR_CPU_IEP_FIR_CLR	0x1c
+
+#define ICTLR_CPU_IER		0x20
+#define ICTLR_CPU_IER_SET	0x24
+#define ICTLR_CPU_IER_CLR	0x28
+#define ICTLR_CPU_IEP_CLASS	0x2C
+
+#define ICTLR_COP_IER		0x30
+#define ICTLR_COP_IER_SET	0x34
+#define ICTLR_COP_IER_CLR	0x38
+#define ICTLR_COP_IEP_CLASS	0x3c
+
+#define TEGRA_MAX_NUM_ICTLRS	5
+
+static int num_ictlrs;
+
+struct tegra_ictlr_info {
+	void __iomem *ictlr_reg_base[TEGRA_MAX_NUM_ICTLRS];
+#ifdef CONFIG_PM_SLEEP
+	u32 cop_ier[TEGRA_MAX_NUM_ICTLRS];
+	u32 cop_iep[TEGRA_MAX_NUM_ICTLRS];
+	u32 cpu_ier[TEGRA_MAX_NUM_ICTLRS];
+	u32 cpu_iep[TEGRA_MAX_NUM_ICTLRS];
+
+	u32 ictlr_wake_mask[TEGRA_MAX_NUM_ICTLRS];
+#endif
+};
+
+static struct tegra_ictlr_info *tegra_ictlr_info;
+
+static inline void tegra_ictlr_write_mask(struct irq_data *d, unsigned long reg)
+{
+	void __iomem *base = d->chip_data;
+	u32 mask;
+
+	mask = BIT(d->hwirq % 32);
+	writel_relaxed(mask, base + reg);
+}
+
+static void tegra_mask(struct irq_data *d)
+{
+	tegra_ictlr_write_mask(d, ICTLR_CPU_IER_CLR);
+	irq_chip_mask_parent(d);
+}
+
+static void tegra_unmask(struct irq_data *d)
+{
+	tegra_ictlr_write_mask(d, ICTLR_CPU_IER_SET);
+	irq_chip_unmask_parent(d);
+}
+
+static void tegra_eoi(struct irq_data *d)
+{
+	tegra_ictlr_write_mask(d, ICTLR_CPU_IEP_FIR_CLR);
+	irq_chip_eoi_parent(d);
+}
+
+static int tegra_retrigger(struct irq_data *d)
+{
+	tegra_ictlr_write_mask(d, ICTLR_CPU_IEP_FIR_SET);
+	return irq_chip_retrigger_hierarchy(d);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int tegra_set_wake(struct irq_data *d, unsigned int enable)
+{
+	u32 irq = d->hwirq;
+	u32 index, mask;
+
+	index = (irq / 32);
+	mask = BIT(irq % 32);
+	if (enable)
+		tegra_ictlr_info->ictlr_wake_mask[index] |= mask;
+	else
+		tegra_ictlr_info->ictlr_wake_mask[index] &= ~mask;
+
+	/*
+	 * Do *not* call into the parent, as the GIC doesn't have any
+	 * wake-up facility...
+	 */
+	return 0;
+}
+
+static int tegra_ictlr_suspend(void)
+{
+	unsigned long flags;
+	int i;
+
+	local_irq_save(flags);
+	for (i = 0; i < num_ictlrs; i++) {
+		void __iomem *ictlr = tegra_ictlr_info->ictlr_reg_base[i];
+		/* Save interrupt state */
+		tegra_ictlr_info->cpu_ier[i] = readl_relaxed(ictlr + ICTLR_CPU_IER);
+		tegra_ictlr_info->cpu_iep[i] = readl_relaxed(ictlr + ICTLR_CPU_IEP_CLASS);
+		tegra_ictlr_info->cop_ier[i] = readl_relaxed(ictlr + ICTLR_COP_IER);
+		tegra_ictlr_info->cop_iep[i] = readl_relaxed(ictlr + ICTLR_COP_IEP_CLASS);
+
+		/* Disable COP interrupts */
+		writel_relaxed(~0ul, ictlr + ICTLR_COP_IER_CLR);
+
+		/* Disable CPU interrupts */
+		writel_relaxed(~0ul, ictlr + ICTLR_CPU_IER_CLR);
+
+		/* Enable the wakeup sources of ictlr */
+		writel_relaxed(tegra_ictlr_info->ictlr_wake_mask[i], ictlr + ICTLR_CPU_IER_SET);
+	}
+	local_irq_restore(flags);
+
+	return 0;
+}
+
+static void tegra_ictlr_resume(void)
+{
+	unsigned long flags;
+	int i;
+
+	local_irq_save(flags);
+	for (i = 0; i < num_ictlrs; i++) {
+		void __iomem *ictlr = tegra_ictlr_info->ictlr_reg_base[i];
+		writel_relaxed(tegra_ictlr_info->cpu_iep[i],
+			       ictlr + ICTLR_CPU_IEP_CLASS);
+		writel_relaxed(~0ul, ictlr + ICTLR_CPU_IER_CLR);
+		writel_relaxed(tegra_ictlr_info->cpu_ier[i],
+			       ictlr + ICTLR_CPU_IER_SET);
+		writel_relaxed(tegra_ictlr_info->cop_iep[i],
+			       ictlr + ICTLR_COP_IEP_CLASS);
+		writel_relaxed(~0ul, ictlr + ICTLR_COP_IER_CLR);
+		writel_relaxed(tegra_ictlr_info->cop_ier[i],
+			       ictlr + ICTLR_COP_IER_SET);
+	}
+	local_irq_restore(flags);
+}
+
+static struct syscore_ops tegra_ictlr_syscore_ops = {
+	.suspend	= tegra_ictlr_suspend,
+	.resume		= tegra_ictlr_resume,
+};
+
+static int tegra_ictlr_syscore_init(void)
+{
+	register_syscore_ops(&tegra_ictlr_syscore_ops);
+
+	return 0;
+}
+#else
+#define tegra_set_wake	NULL
+static inline void tegra_ictlr_syscore_init(void) {}
+#endif
+
+static struct irq_chip tegra_ictlr_chip = {
+	.name		= "ICTLR",
+	.irq_eoi	= tegra_eoi,
+	.irq_mask	= tegra_mask,
+	.irq_unmask	= tegra_unmask,
+	.irq_retrigger	= tegra_retrigger,
+	.irq_set_wake	= tegra_set_wake,
+	.flags		= IRQCHIP_MASK_ON_SUSPEND,
+};
+
+static int tegra_ictlr_domain_xlate(struct irq_domain *domain,
+				    struct device_node *controller,
+				    const u32 *intspec,
+				    unsigned int intsize,
+				    unsigned long *out_hwirq,
+				    unsigned int *out_type)
+{
+	if (domain->of_node != controller)
+		return -EINVAL;	/* Shouldn't happen, really... */
+	if (intsize != 3)
+		return -EINVAL;	/* Not GIC compliant */
+	if (intspec[0] != 0)
+		return -EINVAL;	/* No PPI should point to this domain */
+
+	*out_hwirq = intspec[1];
+	*out_type = intspec[2];
+	return 0;
+}
+
+static int tegra_ictlr_domain_alloc(struct irq_domain *domain,
+				    unsigned int virq,
+				    unsigned int nr_irqs, void *data)
+{
+	struct of_phandle_args *args = data;
+	struct of_phandle_args parent_args;
+	struct tegra_ictlr_info *info = domain->host_data;
+	irq_hw_number_t hwirq;
+	int i;
+
+	if (args->args_count != 3)
+		return -EINVAL;	/* Not GIC compliant */
+	if (args->args[0] != 0)
+		return -EINVAL;	/* No PPI should point to this domain */
+
+	hwirq = args->args[1];
+	if (hwirq >= (num_ictlrs * 32))
+		return -EINVAL;	/* Can't deal with this */
+
+	for (i = 0; i < nr_irqs; i++) {
+		int ictlr = (hwirq + i) / 32;
+
+		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
+					      &tegra_ictlr_chip,
+					      &info->ictlr_reg_base[ictlr]);
+	}
+
+	parent_args = *args;
+	parent_args.np = domain->parent->of_node;
+	return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, &parent_args);
+}
+
+
+static void tegra_ictlr_domain_free(struct irq_domain *domain,
+				    unsigned int virq,
+				    unsigned int nr_irqs)
+{
+	int i;
+
+	for (i = 0; i < nr_irqs; i++) {
+		struct irq_data *d = irq_domain_get_irq_data(domain, virq + i);
+		irq_domain_reset_irq_data(d);
+	}
+}
+
+static struct irq_domain_ops tegra_ictlr_domain_ops = {
+	.xlate	= tegra_ictlr_domain_xlate,
+	.alloc	= tegra_ictlr_domain_alloc,
+	.free	= tegra_ictlr_domain_free,
+};
+
+static int __init tegra_ictlr_init(struct device_node *node,
+				   struct device_node *parent)
+{
+	struct irq_domain *parent_domain, *domain;
+	int err;
+	int i;
+
+	if (!parent) {
+		pr_err("%s: no parent, giving up\n", node->full_name);
+		return -ENODEV;
+	}
+
+	parent_domain = irq_find_host(parent);
+	if (!parent_domain) {
+		pr_err("%s: unable to obtain parent domain\n", node->full_name);
+		return -ENXIO;
+	}
+
+	tegra_ictlr_info = kzalloc(sizeof(*tegra_ictlr_info), GFP_KERNEL);
+	if (!tegra_ictlr_info)
+		return -ENOMEM;
+
+	for (i = 0; i < TEGRA_MAX_NUM_ICTLRS; i++) {
+		void __iomem *base;
+
+		base = of_iomap(node, i);
+		if (!base)
+			break;
+
+		tegra_ictlr_info->ictlr_reg_base[i] = base;
+
+		/* Disable all interrupts */
+		writel_relaxed(~0, base + ICTLR_CPU_IER_CLR);
+		/* All interrupts target IRQ */
+		writel_relaxed(0, base + ICTLR_CPU_IEP_CLASS);
+
+		num_ictlrs++;
+	}
+
+	if (!num_ictlrs) {
+		pr_err("%s: no valid regions, giving up\n", node->full_name);
+		err = -ENOMEM;
+		goto out_free;
+	}
+
+	domain = irq_domain_add_hierarchy(parent_domain, 0, num_ictlrs * 32,
+					  node, &tegra_ictlr_domain_ops,
+					  tegra_ictlr_info);
+	if (!domain) {
+		pr_err("%s: failed to allocated domain\n", node->full_name);
+		err = -ENOMEM;
+		goto out_unmap;
+	}
+
+	tegra_ictlr_syscore_init();
+
+	pr_info("%s: %d interrupts forwarded to %s\n",
+		node->full_name, num_ictlrs * 32, parent->full_name);
+
+	return 0;
+
+out_unmap:
+	for (i = 0; i < num_ictlrs; i++)
+		iounmap(tegra_ictlr_info->ictlr_reg_base[i]);
+out_free:
+	kfree(tegra_ictlr_info);
+	return err;
+}
+
+IRQCHIP_DECLARE(tegra_ictlr, "nvidia,tegra-ictlr", tegra_ictlr_init);
-- 
2.1.3