powerpc/virtex: Fix duplicate level irq events.

The interrupt controller was not handling level interrupts correctly
such that duplicate interrupts were happening. This fixes the problem
and adds edge type interrupts which are needed in Xilinx hardware.

Signed-off-by: John Linn <john.linn@xilinx.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 107 insertions, 10 deletions

diff --git a/arch/powerpc/sysdev/xilinx_intc.c b/arch/powerpc/sysdev/xilinx_intc.c
index a22e1a2df1af..c658b413c9b4 100644
--- a/arch/powerpc/sysdev/xilinx_intc.c
+++ b/arch/powerpc/sysdev/xilinx_intc.c
@@ -41,8 +41,32 @@
 
 static struct irq_host *master_irqhost;
 
+#define XILINX_INTC_MAXIRQS     (32)
+
+/* The following table allows the interrupt type, edge or level,
+ * to be cached after being read from the device tree until the interrupt
+ * is mapped
+ */
+static int xilinx_intc_typetable[XILINX_INTC_MAXIRQS];
+
+/* Map the interrupt type from the device tree to the interrupt types
+ * used by the interrupt subsystem
+ */
+static unsigned char xilinx_intc_map_senses[] = {
+        IRQ_TYPE_EDGE_RISING,
+        IRQ_TYPE_EDGE_FALLING,
+        IRQ_TYPE_LEVEL_HIGH,
+        IRQ_TYPE_LEVEL_LOW,
+};
+
 /*
- * IRQ Chip operations
+ * The interrupt controller is setup such that it doesn't work well with
+ * the level interrupt handler in the kernel because the handler acks the
+ * interrupt before calling the application interrupt handler. To deal with
+ * that, we use 2 different irq chips so that different functions can be
+ * used for level and edge type interrupts.
+ *
+ * IRQ Chip common (across level and edge) operations
  */
 static void xilinx_intc_mask(unsigned int virq)
 {
@@ -52,15 +76,54 @@ static void xilinx_intc_mask(unsigned int virq)
         out_be32(regs + XINTC_CIE, 1 << irq);
 }
 
-static void xilinx_intc_unmask(unsigned int virq)
+static int xilinx_intc_set_type(unsigned int virq, unsigned int flow_type)
+{
+        struct irq_desc *desc = get_irq_desc(virq);
+
+        desc->status &= ~(IRQ_TYPE_SENSE_MASK | IRQ_LEVEL);
+        desc->status |= flow_type & IRQ_TYPE_SENSE_MASK;
+        if (flow_type & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW))
+                desc->status |= IRQ_LEVEL;
+        return 0;
+}
+
+/*
+ * IRQ Chip level operations
+ */
+static void xilinx_intc_level_unmask(unsigned int virq)
 {
         int irq = virq_to_hw(virq);
         void * regs = get_irq_chip_data(virq);
         pr_debug("unmask: %d\n", irq);
         out_be32(regs + XINTC_SIE, 1 << irq);
+
+        /* ack level irqs because they can't be acked during
+         * ack function since the handle_level_irq function
+         * acks the irq before calling the inerrupt handler
+         */
+        out_be32(regs + XINTC_IAR, 1 << irq);
 }
 
-static void xilinx_intc_ack(unsigned int virq)
+static struct irq_chip xilinx_intc_level_irqchip = {
+        .typename = "Xilinx Level INTC",
+        .mask = xilinx_intc_mask,
+        .mask_ack = xilinx_intc_mask,
+        .unmask = xilinx_intc_level_unmask,
+        .set_type = xilinx_intc_set_type,
+};
+
+/*
+ * IRQ Chip edge operations
+ */
+static void xilinx_intc_edge_unmask(unsigned int virq)
+{
+        int irq = virq_to_hw(virq);
+        void *regs = get_irq_chip_data(virq);
+        pr_debug("unmask: %d\n", irq);
+        out_be32(regs + XINTC_SIE, 1 << irq);
+}
+
+static void xilinx_intc_edge_ack(unsigned int virq)
 {
         int irq = virq_to_hw(virq);
         void * regs = get_irq_chip_data(virq);
@@ -68,27 +131,60 @@ static void xilinx_intc_ack(unsigned int virq)
         out_be32(regs + XINTC_IAR, 1 << irq);
 }
 
-static struct irq_chip xilinx_intc_irqchip = {
-        .typename = "Xilinx INTC",
+static struct irq_chip xilinx_intc_edge_irqchip = {
+        .typename = "Xilinx Edge  INTC",
         .mask = xilinx_intc_mask,
-        .unmask = xilinx_intc_unmask,
-        .ack = xilinx_intc_ack,
+        .unmask = xilinx_intc_edge_unmask,
+        .ack = xilinx_intc_edge_ack,
+        .set_type = xilinx_intc_set_type,
 };
 
 /*
  * IRQ Host operations
  */
+
+/**
+ * xilinx_intc_xlate - translate virq# from device tree interrupts property
+ */
+static int xilinx_intc_xlate(struct irq_host *h, struct device_node *ct,
+                                u32 *intspec, unsigned int intsize,
+                                irq_hw_number_t *out_hwirq,
+                                unsigned int *out_flags)
+{
+        if ((intsize < 2) || (intspec[0] >= XILINX_INTC_MAXIRQS))
+                return -EINVAL;
+
+        /* keep a copy of the interrupt type til the interrupt is mapped
+         */
+        xilinx_intc_typetable[intspec[0]] = xilinx_intc_map_senses[intspec[1]];
+
+        /* Xilinx uses 2 interrupt entries, the 1st being the h/w
+         * interrupt number, the 2nd being the interrupt type, edge or level
+         */
+        *out_hwirq = intspec[0];
+        *out_flags = xilinx_intc_map_senses[intspec[1]];
+
+        return 0;
+}
 static int xilinx_intc_map(struct irq_host *h, unsigned int virq,
                                   irq_hw_number_t irq)
 {
         set_irq_chip_data(virq, h->host_data);
-        set_irq_chip_and_handler(virq, &xilinx_intc_irqchip, handle_level_irq);
-        set_irq_type(virq, IRQ_TYPE_NONE);
+
+        if (xilinx_intc_typetable[irq] == IRQ_TYPE_LEVEL_HIGH ||
+            xilinx_intc_typetable[irq] == IRQ_TYPE_LEVEL_LOW) {
+                set_irq_chip_and_handler(virq, &xilinx_intc_level_irqchip,
+                        handle_level_irq);
+        } else {
+                set_irq_chip_and_handler(virq, &xilinx_intc_edge_irqchip,
+                        handle_edge_irq);
+        }
         return 0;
 }
 
 static struct irq_host_ops xilinx_intc_ops = {
         .map = xilinx_intc_map,
+        .xlate = xilinx_intc_xlate,
 };
 
 struct irq_host * __init
@@ -116,7 +212,8 @@ xilinx_intc_init(struct device_node *np)
         out_be32(regs + XINTC_MER, 0x3UL); /* Turn on the Master Enable. */
 
         /* Allocate and initialize an irq_host structure. */
-        irq = irq_alloc_host(np, IRQ_HOST_MAP_LINEAR, 32, &xilinx_intc_ops, -1);
+        irq = irq_alloc_host(np, IRQ_HOST_MAP_LINEAR, XILINX_INTC_MAXIRQS,
+                             &xilinx_intc_ops, -1);
         if (!irq)
                 panic(__FILE__ ": Cannot allocate IRQ host\n");
         irq->host_data = regs;