irqchip: tegra: Add DT-based support for legacy interrupt controller

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>
Link: https://lkml.kernel.org/r/1426088583-15097-3-git-send-email-marc.zyngier@arm.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

2 files changed, 372 insertions, 0 deletions

diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 42965d2476bb..c6d607f1ec50 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 000000000000..d919ecf29cf4
--- /dev/null
+++ b/drivers/irqchip/irq-tegra.c
@@ -0,0 +1,371 @@
+/*
+ * 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,
+#ifdef CONFIG_SMP
+        .irq_set_affinity       = irq_chip_set_affinity_parent,
+#endif
+};
+
+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);