2 files changed, 32 insertions, 6 deletions

diff --git a/arch/powerpc/platforms/85xx/Kconfig b/arch/powerpc/platforms/85xx/Kconfig
index 99bb74da0760..f58184086c8c 100644
--- a/arch/powerpc/platforms/85xx/Kconfig
+++ b/arch/powerpc/platforms/85xx/Kconfig
@@ -18,6 +18,7 @@ config MPC8560_ADS
 config MPC85xx_CDS
         bool "Freescale MPC85xx CDS"
         select DEFAULT_UIMAGE
+        select PPC_I8259
         help
           This option enables support for the MPC85xx CDS board
 
diff --git a/arch/powerpc/platforms/85xx/mpc85xx_cds.c b/arch/powerpc/platforms/85xx/mpc85xx_cds.c
index 71200bdce05a..81b70628df75 100644
--- a/arch/powerpc/platforms/85xx/mpc85xx_cds.c
+++ b/arch/powerpc/platforms/85xx/mpc85xx_cds.c
@@ -24,6 +24,7 @@
 #include <linux/seq_file.h>
 #include <linux/initrd.h>
 #include <linux/module.h>
+#include <linux/interrupt.h>
 #include <linux/fsl_devices.h>
 
 #include <asm/system.h>
@@ -119,16 +120,30 @@ DECLARE_PCI_FIXUP_EARLY(0x3fff, 0x1957, skip_fake_bridge);
 DECLARE_PCI_FIXUP_EARLY(0xff3f, 0x5719, skip_fake_bridge);
 
 #ifdef CONFIG_PPC_I8259
-#warning The i8259 PIC support is currently broken
-static void mpc85xx_8259_cascade(unsigned int irq, struct irq_desc *desc)
+static void mpc85xx_8259_cascade_handler(unsigned int irq,
+                                         struct irq_desc *desc)
 {
         unsigned int cascade_irq = i8259_irq();
 
         if (cascade_irq != NO_IRQ)
+                /* handle an interrupt from the 8259 */
                 generic_handle_irq(cascade_irq);
 
-        desc->chip->eoi(irq);
+        /* check for any interrupts from the shared IRQ line */
+        handle_fasteoi_irq(irq, desc);
 }
+
+static irqreturn_t mpc85xx_8259_cascade_action(int irq, void *dev_id)
+{
+        return IRQ_HANDLED;
+}
+
+static struct irqaction mpc85xxcds_8259_irqaction = {
+        .handler = mpc85xx_8259_cascade_action,
+        .flags = IRQF_SHARED,
+        .mask = CPU_MASK_NONE,
+        .name = "8259 cascade",
+};
 #endif /* PPC_I8259 */
 #endif /* CONFIG_PCI */
 
@@ -137,7 +152,7 @@ static void __init mpc85xx_cds_pic_init(void)
         struct mpic *mpic;
         struct resource r;
         struct device_node *np = NULL;
-#ifdef CONFIG_PPC_I8259
+#if defined(CONFIG_PPC_I8259) && defined(CONFIG_PCI)
         struct device_node *cascade_node = NULL;
         int cascade_irq;
 #endif
@@ -165,7 +180,7 @@ static void __init mpc85xx_cds_pic_init(void)
 
         mpic_init(mpic);
 
-#ifdef CONFIG_PPC_I8259
+#if defined(CONFIG_PPC_I8259) && defined(CONFIG_PCI)
         /* Initialize the i8259 controller */
         for_each_node_by_type(np, "interrupt-controller")
                 if (of_device_is_compatible(np, "chrp,iic")) {
@@ -187,7 +202,17 @@ static void __init mpc85xx_cds_pic_init(void)
         i8259_init(cascade_node, 0);
         of_node_put(cascade_node);
 
-        set_irq_chained_handler(cascade_irq, mpc85xx_8259_cascade);
+        /*
+         *  Hook the interrupt to make sure desc->action is never NULL.
+         *  This is required to ensure that the interrupt does not get
+         *  disabled when the last user of the shared IRQ line frees their
+         *  interrupt.
+         */
+        if (setup_irq(cascade_irq, &mpc85xxcds_8259_irqaction))
+                printk(KERN_ERR "Failed to setup cascade interrupt\n");
+        else
+                /* Success. Connect our low-level cascade handler. */
+                set_irq_handler(cascade_irq, mpc85xx_8259_cascade_handler);
 #endif /* CONFIG_PPC_I8259 */
 }