irqchip: irq-dove: Add PMU interrupt controller.

Dove has a Power Management Unit with its own interrupt
controller. This is chained on the main interrupt controller.  Add a
driver, making use of generic chip where possible.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>

cc: devicetree@vger.kernel.org
cc: pawel.moll@arm.com
cc: mark.rutland@arm.com
cc: swarren@wwwdotorg.org
cc: ian.campbell@citrix.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

3 files changed, 144 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/interrupt-controller/marvell,dove-pmu-intc.txt b/Documentation/devicetree/bindings/interrupt-controller/marvell,dove-pmu-intc.txt
new file mode 100644
index 000000000000..1feb5825d372
--- /dev/null
+++ b/Documentation/devicetree/bindings/interrupt-controller/marvell,dove-pmu-intc.txt
@@ -0,0 +1,17 @@
+Marvell Dove Power Management Unit interrupt controller
+
+Required properties:
+- compatible: shall be "marvell,dove-pmu-intc"
+- reg: base address of PMU interrupt registers starting with CAUSE register
+- interrupts: PMU interrupt of the main interrupt controller
+- interrupt-controller: identifies the node as an interrupt controller
+- #interrupt-cells: number of cells to encode an interrupt source, shall be 1
+
+Example:
+        pmu_intc: pmu-interrupt-ctrl@d0050 {
+                compatible = "marvell,dove-pmu-intc";
+                interrupt-controller;
+                #interrupt-cells = <1>;
+                reg = <0xd0050 0x8>;
+                interrupts = <33>;
+        };
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index c60b9010b152..f743006ce7ad 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -1,6 +1,7 @@
 obj-$(CONFIG_IRQCHIP)                   += irqchip.o
 
 obj-$(CONFIG_ARCH_BCM2835)              += irq-bcm2835.o
+obj-$(CONFIG_ARCH_DOVE)                 += irq-dove.o
 obj-$(CONFIG_ARCH_EXYNOS)               += exynos-combiner.o
 obj-$(CONFIG_ARCH_MMP)                  += irq-mmp.o
 obj-$(CONFIG_ARCH_MVEBU)                += irq-armada-370-xp.o
diff --git a/drivers/irqchip/irq-dove.c b/drivers/irqchip/irq-dove.c
new file mode 100644
index 000000000000..788acd89848a
--- /dev/null
+++ b/drivers/irqchip/irq-dove.c
@@ -0,0 +1,126 @@
+/*
+ * Marvell Dove SoCs PMU IRQ chip driver.
+ *
+ * Andrew Lunn <andrew@lunn.ch>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <asm/exception.h>
+#include <asm/mach/irq.h>
+
+#include "irqchip.h"
+
+#define DOVE_PMU_IRQ_CAUSE      0x00
+#define DOVE_PMU_IRQ_MASK       0x04
+
+static void dove_pmu_irq_handler(unsigned int irq, struct irq_desc *desc)
+{
+        struct irq_domain *d = irq_get_handler_data(irq);
+        struct irq_chip_generic *gc = irq_get_domain_generic_chip(d, 0);
+        u32 stat = readl_relaxed(gc->reg_base + DOVE_PMU_IRQ_CAUSE) &
+                   gc->mask_cache;
+
+        while (stat) {
+                u32 hwirq = ffs(stat) - 1;
+
+                generic_handle_irq(irq_find_mapping(d, gc->irq_base + hwirq));
+                stat &= ~(1 << hwirq);
+        }
+}
+
+static void pmu_irq_ack(struct irq_data *d)
+{
+        struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+        struct irq_chip_type *ct = irq_data_get_chip_type(d);
+        u32 mask = ~d->mask;
+
+        /*
+         * The PMU mask register is not RW0C: it is RW.  This means that
+         * the bits take whatever value is written to them; if you write
+         * a '1', you will set the interrupt.
+         *
+         * Unfortunately this means there is NO race free way to clear
+         * these interrupts.
+         *
+         * So, let's structure the code so that the window is as small as
+         * possible.
+         */
+        irq_gc_lock(gc);
+        mask &= irq_reg_readl(gc->reg_base +  ct->regs.ack);
+        irq_reg_writel(mask, gc->reg_base +  ct->regs.ack);
+        irq_gc_unlock(gc);
+}
+
+static int __init dove_pmu_irq_init(struct device_node *np,
+                                    struct device_node *parent)
+{
+        unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
+        struct resource r;
+        struct irq_domain *domain;
+        struct irq_chip_generic *gc;
+        int ret, irq, nrirqs = 7;
+
+        domain = irq_domain_add_linear(np, nrirqs,
+                                       &irq_generic_chip_ops, NULL);
+        if (!domain) {
+                pr_err("%s: unable to add irq domain\n", np->name);
+                return -ENOMEM;
+        }
+
+        ret = irq_alloc_domain_generic_chips(domain, nrirqs, 1, np->name,
+                             handle_level_irq, clr, 0, IRQ_GC_INIT_MASK_CACHE);
+        if (ret) {
+                pr_err("%s: unable to alloc irq domain gc\n", np->name);
+                return ret;
+        }
+
+        ret = of_address_to_resource(np, 0, &r);
+        if (ret) {
+                pr_err("%s: unable to get resource\n", np->name);
+                return ret;
+        }
+
+        if (!request_mem_region(r.start, resource_size(&r), np->name)) {
+                pr_err("%s: unable to request mem region\n", np->name);
+                return -ENOMEM;
+        }
+
+        /* Map the parent interrupt for the chained handler */
+        irq = irq_of_parse_and_map(np, 0);
+        if (irq <= 0) {
+                pr_err("%s: unable to parse irq\n", np->name);
+                return -EINVAL;
+        }
+
+        gc = irq_get_domain_generic_chip(domain, 0);
+        gc->reg_base = ioremap(r.start, resource_size(&r));
+        if (!gc->reg_base) {
+                pr_err("%s: unable to map resource\n", np->name);
+                return -ENOMEM;
+        }
+
+        gc->chip_types[0].regs.ack = DOVE_PMU_IRQ_CAUSE;
+        gc->chip_types[0].regs.mask = DOVE_PMU_IRQ_MASK;
+        gc->chip_types[0].chip.irq_ack = pmu_irq_ack;
+        gc->chip_types[0].chip.irq_mask = irq_gc_mask_clr_bit;
+        gc->chip_types[0].chip.irq_unmask = irq_gc_mask_set_bit;
+
+        /* mask and clear all interrupts */
+        writel(0, gc->reg_base + DOVE_PMU_IRQ_MASK);
+        writel(0, gc->reg_base + DOVE_PMU_IRQ_CAUSE);
+
+        irq_set_handler_data(irq, domain);
+        irq_set_chained_handler(irq, dove_pmu_irq_handler);
+
+        return 0;
+}
+IRQCHIP_DECLARE(dove_pmu_intc,
+                "marvell,dove-pmu-intc", dove_pmu_irq_init);