diff mbox

[v4,02/21] irqchip: tegra: add DT-based support for legacy interrupt controller

Message ID 1421660655-21394-3-git-send-email-marc.zyngier@arm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Marc Zyngier Jan. 19, 2015, 9:43 a.m. UTC
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 | 368 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 369 insertions(+)
 create mode 100644 drivers/irqchip/irq-tegra.c

Comments

Peter De Schrijver Jan. 20, 2015, 7:51 a.m. UTC | #1
On Mon, Jan 19, 2015 at 09:43:56AM +0000, Marc Zyngier wrote:
> 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.
> 

Note that the GIC isn't really stacked on top of the LIC. Each IRQ is
presented to both the LIC and the GIC (as an SPI). The LIC is only used
to wakeup the CPU in case the GIC is not powered. The LIC can also
generate interrupts towards the AVP/ARM7, but that's outside the scope
of Linux ofcourse. The LIC can also be used to force an IRQ and that
forced IRQ will be propagated to the GIC. (see also figure 2, page 36
of the Tegra K1 TRM)

Cheers,

Peter.

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diff mbox

Patch

diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 9516a32..59f34be 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..e1ac65e
--- /dev/null
+++ b/drivers/irqchip/irq-tegra.c
@@ -0,0 +1,368 @@ 
+/*
+ * 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 <dt-bindings/interrupt-controller/arm-gic.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 unsigned int num_ictlrs;
+
+struct tegra_ictlr_soc {
+	unsigned int num_ictlrs;
+};
+
+static const struct tegra_ictlr_soc tegra20_ictlr_soc = {
+	.num_ictlrs = 4,
+};
+
+static const struct tegra_ictlr_soc tegra30_ictlr_soc = {
+	.num_ictlrs = 5,
+};
+
+static const struct of_device_id ictlr_matches[] = {
+	{ .compatible = "nvidia,tegra30-ictlr", .data = &tegra30_ictlr_soc },
+	{ .compatible = "nvidia,tegra20-ictlr", .data = &tegra20_ictlr_soc },
+	{ }
+};
+
+struct tegra_ictlr_info {
+	void __iomem *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 *lic;
+
+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)
+		lic->ictlr_wake_mask[index] |= mask;
+	else
+		lic->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;
+	unsigned int i;
+
+	local_irq_save(flags);
+	for (i = 0; i < num_ictlrs; i++) {
+		void __iomem *ictlr = lic->base[i];
+
+		/* Save interrupt state */
+		lic->cpu_ier[i] = readl_relaxed(ictlr + ICTLR_CPU_IER);
+		lic->cpu_iep[i] = readl_relaxed(ictlr + ICTLR_CPU_IEP_CLASS);
+		lic->cop_ier[i] = readl_relaxed(ictlr + ICTLR_COP_IER);
+		lic->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(lic->ictlr_wake_mask[i], ictlr + ICTLR_CPU_IER_SET);
+	}
+	local_irq_restore(flags);
+
+	return 0;
+}
+
+static void tegra_ictlr_resume(void)
+{
+	unsigned long flags;
+	unsigned int i;
+
+	local_irq_save(flags);
+	for (i = 0; i < num_ictlrs; i++) {
+		void __iomem *ictlr = lic->base[i];
+
+		writel_relaxed(lic->cpu_iep[i],
+			       ictlr + ICTLR_CPU_IEP_CLASS);
+		writel_relaxed(~0ul, ictlr + ICTLR_CPU_IER_CLR);
+		writel_relaxed(lic->cpu_ier[i],
+			       ictlr + ICTLR_CPU_IER_SET);
+		writel_relaxed(lic->cop_iep[i],
+			       ictlr + ICTLR_COP_IEP_CLASS);
+		writel_relaxed(~0ul, ictlr + ICTLR_COP_IER_CLR);
+		writel_relaxed(lic->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 void tegra_ictlr_syscore_init(void)
+{
+	register_syscore_ops(&tegra_ictlr_syscore_ops);
+}
+#else
+#define tegra_set_wake	NULL
+static inline void tegra_ictlr_syscore_init(void) {}
+#endif
+
+static struct irq_chip tegra_ictlr_chip = {
+	.name		= "LIC",
+	.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] != GIC_SPI)
+		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;
+	unsigned int i;
+
+	if (args->args_count != 3)
+		return -EINVAL;	/* Not GIC compliant */
+	if (args->args[0] != GIC_SPI)
+		return -EINVAL;	/* No PPI should point to this domain */
+
+	hwirq = args->args[1];
+	if (hwirq >= (num_ictlrs * 32))
+		return -EINVAL;
+
+	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->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)
+{
+	unsigned 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 const 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;
+	const struct of_device_id *match;
+	const struct tegra_ictlr_soc *soc;
+	unsigned int i;
+	int err;
+
+	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;
+	}
+
+	match = of_match_node(ictlr_matches, node);
+	if (!match)		/* Should never happen... */
+		return -ENODEV;
+
+	soc = match->data;
+
+	lic = kzalloc(sizeof(*lic), GFP_KERNEL);
+	if (!lic)
+		return -ENOMEM;
+
+	for (i = 0; i < TEGRA_MAX_NUM_ICTLRS; i++) {
+		void __iomem *base;
+
+		base = of_iomap(node, i);
+		if (!base)
+			break;
+
+		lic->base[i] = base;
+
+		/* Disable all interrupts */
+		writel_relaxed(~0UL, 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;
+	}
+
+	WARN(num_ictlrs != soc->num_ictlrs,
+	     "%s: Found %u interrupt controllers in DT; expected %u.\n",
+	     node->full_name, num_ictlrs, soc->num_ictlrs);
+
+
+	domain = irq_domain_add_hierarchy(parent_domain, 0, num_ictlrs * 32,
+					  node, &tegra_ictlr_domain_ops,
+					  lic);
+	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(lic->base[i]);
+out_free:
+	kfree(lic);
+	return err;
+}
+
+IRQCHIP_DECLARE(tegra20_ictlr, "nvidia,tegra20-ictlr", tegra_ictlr_init);
+IRQCHIP_DECLARE(tegra30_ictlr, "nvidia,tegra30-ictlr", tegra_ictlr_init);