128 inputs, 24 outputs (to GIC SPI 0-23)
---
There might be a few things wrong with this driver.
When I cat /proc/interrupts the interrupt count appears
to be bogus (as if level IRQ counts are added to edge
IRQ counts). Did I mess something up with the IRQ domains?
---
 .../interrupt-controller/sigma,smp8759-intc.txt    |  18 ++
 drivers/irqchip/Makefile                           |   2 +-
 drivers/irqchip/irq-smp8759.c                      | 203 +++++++++++++++++++++
 3 files changed, 222 insertions(+), 1 deletion(-)
 create mode 100644 
Documentation/devicetree/bindings/interrupt-controller/sigma,smp8759-intc.txt
 create mode 100644 drivers/irqchip/irq-smp8759.c

diff --git 
a/Documentation/devicetree/bindings/interrupt-controller/sigma,smp8759-intc.txt 
b/Documentation/devicetree/bindings/interrupt-controller/sigma,smp8759-intc.txt
new file mode 100644
index 000000000000..9ec922f3c0a4
--- /dev/null
+++ 
b/Documentation/devicetree/bindings/interrupt-controller/sigma,smp8759-intc.txt
@@ -0,0 +1,18 @@
+Sigma Designs SMP8759 interrupt router
+
+Required properties:
+- compatible: "sigma,smp8759-intc"
+- reg: address/size of register area
+- interrupt-controller
+- #interrupt-cells: <2>  (hwirq and trigger_type)
+- interrupt-parent: parent phandle
+
+Example:
+
+       interrupt-controller@6f800 {
+               compatible = "sigma,smp8759-intc";
+               reg = <0x6f800 0x430>;
+               interrupt-controller;
+               #interrupt-cells = <2>;
+               interrupt-parent = <&gic>;
+       };
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index e4dbfc85abdb..013104923b71 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -47,7 +47,7 @@ obj-$(CONFIG_VERSATILE_FPGA_IRQ)      += irq-versatile-fpga.o
 obj-$(CONFIG_ARCH_NSPIRE)              += irq-zevio.o
 obj-$(CONFIG_ARCH_VT8500)              += irq-vt8500.o
 obj-$(CONFIG_ST_IRQCHIP)               += irq-st.o
-obj-$(CONFIG_TANGO_IRQ)                        += irq-tango.o
+obj-$(CONFIG_TANGO_IRQ)                        += irq-tango.o irq-smp8759.o
 obj-$(CONFIG_TB10X_IRQC)               += irq-tb10x.o
 obj-$(CONFIG_TS4800_IRQ)               += irq-ts4800.o
 obj-$(CONFIG_XTENSA)                   += irq-xtensa-pic.o
diff --git a/drivers/irqchip/irq-smp8759.c b/drivers/irqchip/irq-smp8759.c
new file mode 100644
index 000000000000..ec7fee4574ef
--- /dev/null
+++ b/drivers/irqchip/irq-smp8759.c
@@ -0,0 +1,203 @@
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
+
+#define IRQ_MAX                128
+#define SPI_MAX                24 /* 24 output lines routed to SPI 0-23 */
+#define LEVEL_SPI      17
+#define IRQ_ENABLE     BIT(31)
+
+/*
+ * 128 inputs mapped to 24 outputs
+ * LEVEL_HIGH IRQs are muxed on output line 'LEVEL_SPI'
+ * EDGE_RISING IRQs get a dedicated output line
+ * gic_spi_to_tango_hwirq array maps GIC SPI hwirq to tango hwirq
+ */
+struct tango_intc {
+       DECLARE_BITMAP(enabled, IRQ_MAX);
+       spinlock_t lock;
+       void __iomem *config;
+       void __iomem *status;
+       struct irq_domain *dom;
+       u8 gic_spi_to_tango_hwirq[SPI_MAX];
+};
+
+static void tango_level_isr(struct irq_desc *desc)
+{
+       unsigned int pos, virq;
+       struct irq_chip *chip = irq_desc_get_chip(desc);
+       struct tango_intc *intc = irq_desc_get_handler_data(desc);
+       DECLARE_BITMAP(status, IRQ_MAX);
+
+       chained_irq_enter(chip, desc);
+
+       memcpy_fromio(status, intc->status, IRQ_MAX / BITS_PER_BYTE);
+       spin_lock(&intc->lock);
+       bitmap_and(status, status, intc->enabled, IRQ_MAX);
+       spin_unlock(&intc->lock);
+       for_each_set_bit(pos, status, IRQ_MAX) {
+               virq = irq_find_mapping(intc->dom, pos);
+               generic_handle_irq(virq);
+       }
+
+       chained_irq_exit(chip, desc);
+}
+
+static void tango_edge_isr(struct irq_desc *desc)
+{
+       unsigned int virq;
+       struct irq_data *d = &desc->irq_data;
+       struct irq_chip *chip = irq_desc_get_chip(desc);
+       struct tango_intc *intc = irq_desc_get_handler_data(desc);
+
+       /* I don't know how to get the SPI number, d->hwirq - 32 is a hack */
+       int hwirq = intc->gic_spi_to_tango_hwirq[d->hwirq - 32];
+       //printk("%s: SPI=%lu hwirq=%d\n", __func__, d->hwirq, hwirq);
+
+       chained_irq_enter(chip, desc);
+       virq = irq_find_mapping(intc->dom, hwirq);
+       generic_handle_irq(virq);
+       chained_irq_exit(chip, desc);
+}
+
+static void tango_mask(struct irq_data *data)
+{
+       unsigned long flags;
+       struct tango_intc *intc = data->chip_data;
+
+       spin_lock_irqsave(&intc->lock, flags);
+       __clear_bit(data->hwirq, intc->enabled);
+       writel_relaxed(0, intc->config + data->hwirq * 4);
+       spin_unlock_irqrestore(&intc->lock, flags);
+}
+
+static void tango_unmask(struct irq_data *data)
+{
+       unsigned long flags;
+       struct tango_intc *intc = data->chip_data;
+
+#if 0
+       if (!in_irq() && !in_interrupt()) {
+               printk("HWIRQ=%lu mask=%u\n", data->hwirq, data->mask);
+               dump_stack();
+       }
+#endif
+
+       spin_lock_irqsave(&intc->lock, flags);
+       __set_bit(data->hwirq, intc->enabled);
+       writel_relaxed(IRQ_ENABLE | data->mask, intc->config + data->hwirq * 4);
+       spin_unlock_irqrestore(&intc->lock, flags);
+}
+
+static int find_free_output_line(struct tango_intc *intc)
+{
+       int spi;
+
+       for (spi = 0; spi < SPI_MAX; ++spi)
+               if (intc->gic_spi_to_tango_hwirq[spi] == 0)
+                       return spi;
+
+       return -ENOSPC;
+}
+
+int tango_set_type(struct irq_data *data, unsigned int flow_type)
+{
+       struct tango_intc *intc = data->chip_data;
+       printk("%s: IRQ=%lu type=%x\n", __func__, data->hwirq, flow_type);
+       dump_stack();
+       if (flow_type & IRQ_TYPE_LEVEL_HIGH) {
+               data->mask = LEVEL_SPI;
+               return 0;
+       }
+
+       if (flow_type & IRQ_TYPE_EDGE_RISING) {
+               int res = find_free_output_line(intc);
+               if (res < 0)
+                       return res;
+               data->mask = res;
+               intc->gic_spi_to_tango_hwirq[res] = data->hwirq;
+               printk("Map tango hwirq %lu to GIC SPI %d\n", data->hwirq, res);
+               return 0;
+       }
+
+       /* LEVEL_LOW and EDGE_FALLING are not supported */
+       return -ENOSYS;
+}
+
+static struct irq_chip tango_chip = {
+       .name           = "tango",
+       .irq_mask       = tango_mask,
+       .irq_unmask     = tango_unmask,
+       .irq_set_type   = tango_set_type,
+};
+
+static int tango_map(struct irq_domain *dom, unsigned int virq, 
irq_hw_number_t hw)
+{
+       struct tango_intc *intc = dom->host_data;
+       struct irq_desc *desc = irq_to_desc(virq);
+       printk("%s: dom=%p virq=%u hwirq=%lu desc=%p\n", __func__, dom, virq, 
hw, desc);
+       irq_domain_set_info(dom, virq, hw, &tango_chip, intc, 
handle_simple_irq, NULL, NULL);
+       return 0;
+}
+
+static void tango_unmap(struct irq_domain *d, unsigned int virq)
+{
+       printk("%s: dom=%p virq=%u\n", __func__, d, virq);
+       dump_stack();
+}
+
+struct irq_domain_ops dom_ops =
+{
+       .map    = tango_map,
+       .unmap  = tango_unmap,
+       .xlate  = irq_domain_xlate_twocell,
+};
+
+#include <dt-bindings/interrupt-controller/arm-gic.h>
+
+static int __init map_irq(struct device_node *gic, int irq, int type)
+{
+       struct of_phandle_args irq_data = { gic, 3, { GIC_SPI, irq, type }};
+       return irq_create_of_mapping(&irq_data);
+}
+
+static int __init tango_irq_init(struct device_node *node, struct device_node 
*parent)
+{
+       int spi, virq;
+       struct irq_domain *irq_dom;
+       void __iomem *base;
+       struct tango_intc *intc = kzalloc(sizeof(*intc), GFP_KERNEL);
+
+       base = of_iomap(node, 0);
+       if (!base)
+               panic("%s: of_iomap failed", node->name);
+
+       virq = map_irq(parent, LEVEL_SPI, IRQ_TYPE_LEVEL_HIGH);
+       if (!virq)
+               panic("%s: Failed to map IRQ %d\n", node->name, LEVEL_SPI);
+
+       irq_set_chained_handler_and_data(virq, tango_level_isr, intc);
+
+       for (spi = 0; spi < SPI_MAX; ++spi) {
+               if (spi == LEVEL_SPI)
+                       continue;
+
+               virq = map_irq(parent, spi, IRQ_TYPE_EDGE_RISING);
+               if (!virq)
+                       panic("%s: Failed to map IRQ %d\n", node->name, spi);
+
+               irq_set_chained_handler_and_data(virq, tango_edge_isr, intc);
+       }
+
+       irq_dom = irq_domain_add_linear(node, IRQ_MAX, &dom_ops, intc);
+
+       spin_lock_init(&intc->lock);
+       intc->config = base;
+       intc->status = base + 0x420;
+       intc->dom = irq_dom;
+       intc->gic_spi_to_tango_hwirq[LEVEL_SPI] = ~0;
+
+       return 0;
+}
+IRQCHIP_DECLARE(tango_intc, "sigma,smp8759-intc", tango_irq_init);

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