viafb: Add a simple interrupt management infrastructure

[deliverable/linux.git] / drivers / video / via / via-core.c

diff --git a/drivers/video/via/via-core.c b/drivers/video/via/via-core.c
index 5a78ef9cb382e1244317d021648237fa1a61522f..701b95575747ea00f7dfd26d85166fa5a97028e6 100644 (file)
--- a/drivers/video/via/via-core.c
+++ b/drivers/video/via/via-core.c
@@ -34,6 +34,65 @@ static struct via_port_cfg adap_configs[] = {
 static struct viafb_dev global_dev;
 
 
+/*
+ * Basic register access; spinlock required.
+ */
+static inline void viafb_mmio_write(int reg, u32 v)
+{
+       iowrite32(v, global_dev.engine_mmio + reg);
+}
+
+static inline int viafb_mmio_read(int reg)
+{
+       return ioread32(global_dev.engine_mmio + reg);
+}
+
+/* ---------------------------------------------------------------------- */
+/*
+ * Interrupt management.  We have a single IRQ line for a lot of
+ * different functions, so we need to share it.  The design here
+ * is that we don't want to reimplement the shared IRQ code here;
+ * we also want to avoid having contention for a single handler thread.
+ * So each subdev driver which needs interrupts just requests
+ * them directly from the kernel.  We just have what's needed for
+ * overall access to the interrupt control register.
+ */
+
+/*
+ * Which interrupts are enabled now?
+ */
+static u32 viafb_enabled_ints;
+
+static void viafb_int_init(void)
+{
+       viafb_enabled_ints = 0;
+
+       viafb_mmio_write(VDE_INTERRUPT, 0);
+}
+
+/*
+ * Allow subdevs to ask for specific interrupts to be enabled.  These
+ * functions must be called with reg_lock held
+ */
+void viafb_irq_enable(u32 mask)
+{
+       viafb_enabled_ints |= mask;
+       viafb_mmio_write(VDE_INTERRUPT, viafb_enabled_ints | VDE_I_ENABLE);
+}
+EXPORT_SYMBOL_GPL(viafb_irq_enable);
+
+void viafb_irq_disable(u32 mask)
+{
+       viafb_enabled_ints &= ~mask;
+       if (viafb_enabled_ints == 0)
+               viafb_mmio_write(VDE_INTERRUPT, 0);  /* Disable entirely */
+       else
+               viafb_mmio_write(VDE_INTERRUPT,
+                               viafb_enabled_ints | VDE_I_ENABLE);
+}
+EXPORT_SYMBOL_GPL(viafb_irq_disable);
+
+
 /*
  * Figure out how big our framebuffer memory is.  Kind of ugly,
  * but evidently we can't trust the information found in the
@@ -275,8 +334,10 @@ static int __devinit via_pci_probe(struct pci_dev *pdev,
        if (ret)
                goto out_disable;
        /*
-        * Create our subdevices.  Continue even if some things fail.
+        * Set up interrupts and create our subdevices.  Continue even if
+        * some things fail.
         */
+       viafb_int_init();
        via_setup_subdevs(&global_dev);
        /*
         * Set up the framebuffer.
@@ -284,6 +345,7 @@ static int __devinit via_pci_probe(struct pci_dev *pdev,
        ret = via_fb_pci_probe(&global_dev);
        if (ret)
                goto out_subdevs;
+
        return 0;
 
 out_subdevs: