[PATCH v2 03/13] irqchip: Add a driver for the Microsemi Ocelot controller

[Alexandre Belloni <alexandre.belloni@free-electrons.com>]

The Microsemi Ocelot SoC has a pretty simple IRQ controller in its ICPU
block. Add a driver for it.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
---
 drivers/irqchip/Kconfig           |   5 ++
 drivers/irqchip/Makefile          |   1 +
 drivers/irqchip/irq-mscc-ocelot.c | 109 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 115 insertions(+)
 create mode 100644 drivers/irqchip/irq-mscc-ocelot.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index c70476b34a53..9605a872da1c 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -286,6 +286,11 @@ config IRQ_MXS
        select IRQ_DOMAIN
        select STMP_DEVICE
 
+config MSCC_OCELOT_IRQ
+       bool
+       select IRQ_DOMAIN
+       select GENERIC_IRQ_CHIP
+
 config MVEBU_GICP
        bool
 
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index d2df34a54d38..dc549701782d 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -72,6 +72,7 @@ obj-$(CONFIG_ARCH_SA1100)             += irq-sa11x0.o
 obj-$(CONFIG_INGENIC_IRQ)              += irq-ingenic.o
 obj-$(CONFIG_IMX_GPCV2)                        += irq-imx-gpcv2.o
 obj-$(CONFIG_PIC32_EVIC)               += irq-pic32-evic.o
+obj-$(CONFIG_MSCC_OCELOT_IRQ)          += irq-mscc-ocelot.o
 obj-$(CONFIG_MVEBU_GICP)               += irq-mvebu-gicp.o
 obj-$(CONFIG_MVEBU_ICU)                        += irq-mvebu-icu.o
 obj-$(CONFIG_MVEBU_ODMI)               += irq-mvebu-odmi.o
diff --git a/drivers/irqchip/irq-mscc-ocelot.c 
b/drivers/irqchip/irq-mscc-ocelot.c
new file mode 100644
index 000000000000..c2cf46758a59
--- /dev/null
+++ b/drivers/irqchip/irq-mscc-ocelot.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/*
+ * Microsemi Ocelot IRQ controller driver
+ *
+ * License: Dual MIT/GPL
+ * Copyright (c) 2017 Microsemi Corporation
+ */
+#include <linux/bitops.h>
+#include <linux/irq.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/interrupt.h>
+
+#define ICPU_CFG_INTR_INTR_STICKY      0x10
+#define ICPU_CFG_INTR_INTR_ENA         0x18
+#define ICPU_CFG_INTR_INTR_ENA_CLR     0x1c
+#define ICPU_CFG_INTR_INTR_ENA_SET     0x20
+#define ICPU_CFG_INTR_DST_INTR_IDENT(x)        (0x38 + 0x4 * (x))
+#define ICPU_CFG_INTR_INTR_TRIGGER(x)  (0x5c + 0x4 * (x))
+
+#define OCELOT_NR_IRQ 24
+
+static void ocelot_irq_unmask(struct irq_data *data)
+{
+       struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
+       struct irq_chip_type *ct = irq_data_get_chip_type(data);
+       unsigned int mask = data->mask;
+       u32 val;
+
+       irq_gc_lock(gc);
+       val = irq_reg_readl(gc, ICPU_CFG_INTR_INTR_TRIGGER(0)) |
+             irq_reg_readl(gc, ICPU_CFG_INTR_INTR_TRIGGER(1));
+       if ((val & mask) == 0)
+               irq_reg_writel(gc, mask, ICPU_CFG_INTR_INTR_STICKY);
+
+       *ct->mask_cache &= ~mask;
+       irq_reg_writel(gc, mask, ICPU_CFG_INTR_INTR_ENA_SET);
+       irq_gc_unlock(gc);
+}
+
+static void ocelot_irq_handler(struct irq_desc *desc)
+{
+       struct irq_chip *chip = irq_desc_get_chip(desc);
+       struct irq_domain *d = irq_desc_get_handler_data(desc);
+       struct irq_chip_generic *gc = irq_get_domain_generic_chip(d, 0);
+       u32 reg = irq_reg_readl(gc, ICPU_CFG_INTR_DST_INTR_IDENT(0));
+
+       chained_irq_enter(chip, desc);
+
+       while (reg) {
+               u32 hwirq = __fls(reg);
+
+               generic_handle_irq(irq_find_mapping(d, hwirq));
+               reg &= ~(BIT(hwirq));
+       }
+
+       chained_irq_exit(chip, desc);
+}
+
+static int __init ocelot_irq_init(struct device_node *node,
+                                 struct device_node *parent)
+{
+       struct irq_domain *domain;
+       struct irq_chip_generic *gc;
+       int parent_irq, ret;
+
+       domain = irq_domain_add_linear(node, OCELOT_NR_IRQ,
+                                      &irq_generic_chip_ops, NULL);
+       if (!domain) {
+               pr_err("%s: unable to add irq domain\n", node->name);
+               return -ENOMEM;
+       }
+
+       ret = irq_alloc_domain_generic_chips(domain, OCELOT_NR_IRQ, 1,
+                                            "icpu", handle_level_irq,
+                                            0, 0, 0);
+       if (ret) {
+               pr_err("%s: unable to alloc irq domain gc\n", node->name);
+               return ret;
+       }
+
+       gc = irq_get_domain_generic_chip(domain, 0);
+       gc->reg_base = of_iomap(node, 0);
+       if (!gc->reg_base) {
+               pr_err("%s: unable to map resource\n", node->name);
+               return -ENOMEM;
+       }
+
+       gc->chip_types[0].regs.ack = ICPU_CFG_INTR_INTR_STICKY;
+       gc->chip_types[0].regs.mask = ICPU_CFG_INTR_INTR_ENA_CLR;
+       gc->chip_types[0].chip.irq_ack = irq_gc_ack_set_bit;
+       gc->chip_types[0].chip.irq_mask = irq_gc_mask_set_bit;
+       gc->chip_types[0].chip.irq_unmask = ocelot_irq_unmask;
+
+       irq_reg_writel(gc, 0, ICPU_CFG_INTR_INTR_ENA); /* Mask all */
+       irq_reg_writel(gc, 0xffffffff, ICPU_CFG_INTR_INTR_STICKY); /* Ack 
pending */
+
+       parent_irq = irq_of_parse_and_map(node, 0);
+       if (!parent_irq)
+               return -EINVAL;
+
+       irq_set_chained_handler_and_data(parent_irq, ocelot_irq_handler,
+                                        domain);
+
+       return 0;
+}
+IRQCHIP_DECLARE(ocelot_icpu, "mscc,ocelot-icpu-intr", ocelot_irq_init);
-- 
2.15.1