Fix access to ez80 I/O address space

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@748 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 19 insertions, 2 deletions

diff --git a/nuttx/include/nuttx/arch.h b/nuttx/include/nuttx/arch.h
index 7f054e088..40667b077 100644
--- a/nuttx/include/nuttx/arch.h
+++ b/nuttx/include/nuttx/arch.h
@@ -379,7 +379,18 @@ EXTERN boolean up_interrupt_context(void);
  * Name: up_enable_irq
  *
  * Description:
- *   Enable the IRQ specified by 'irq'
+ *   On many architectures, there are three levels of interrupt enabling: (1)
+ *   at the global level, (2) at the level of the interrupt controller,
+ *   and (3) at the device level.  In order to receive interrupts, they
+ *   must be enabled at all three levels.
+ *
+ *   This function implements enabling of the device specified by 'irq'
+ *   at the interrupt controller level if supported by the architecture
+ *   (irqsave() supports the global level, the device level is hardware
+ *   specific).
+ *
+ *   Since this API is not supported on all architectures, it should be
+ *   avoided in common implementations where possible.
  *
  ****************************************************************************/
 
@@ -389,7 +400,13 @@ EXTERN void up_enable_irq(int irq);
  * Name: up_disable_irq
  *
  * Description:
- *   Disable the IRQ specified by 'irq'
+ *   This function implements disabling of the device specified by 'irq'
+ *   at the interrupt controller level if supported by the architecture
+ *   (irqsave() supports the global level, the device level is hardware
+ *   specific).
+ *
+ *   Since this API is not supported on all architectures, it should be
+ *   avoided in common implementations where possible.
  *
  ****************************************************************************/