1 files changed, 100 insertions, 0 deletions
diff --git a/sos-code-article6.5/hwcore/irq.c b/sos-code-article6.5/hwcore/irq.c
new file mode 100644
index 0000000..6722027
--- /dev/null
+++ b/sos-code-article6.5/hwcore/irq.c
@@ -0,0 +1,100 @@
+/* Copyright (C) 2004  David Decotigny
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License
+   as published by the Free Software Foundation; either version 2
+   of the License, or (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+   USA. 
+*/
+#include "idt.h"
+#include "i8259.h"
+
+#include "irq.h"
+
+/** array of IRQ wrappers, defined in irq_wrappers.S */
+extern sos_vaddr_t sos_irq_wrapper_array[SOS_IRQ_NUM];
+
+/** arrays of IRQ handlers, shared with irq_wrappers.S */
+sos_irq_handler_t sos_irq_handler_array[SOS_IRQ_NUM] = { NULL, };
+
+/** Number of interrupt handlers that are currently executing */
+sos_ui32_t sos_irq_nested_level_counter;
+
+sos_ret_t sos_irq_subsystem_setup(void)
+{
+  sos_irq_nested_level_counter = 0;
+  return sos_i8259_subsystem_setup();
+}
+
+
+sos_ret_t sos_irq_set_routine(int irq_level,
+			      sos_irq_handler_t routine)
+{
+  sos_ret_t retval;
+  sos_ui32_t flags;
+  
+  if ((irq_level < 0) || (irq_level >= SOS_IRQ_NUM))
+    return -SOS_EINVAL;
+  
+  sos_disable_IRQs(flags);
+
+  retval = SOS_OK;
+
+  /* Set the irq routine to be called by the IRQ wrapper */
+  sos_irq_handler_array[irq_level] = routine;
+
+  /* If the irq is to be enabled, update the IDT with the IRQ
+     wrapper */
+  if (routine != NULL)
+    {
+      retval
+	= sos_idt_set_handler(SOS_IRQ_BASE + irq_level,
+			      (sos_vaddr_t) sos_irq_wrapper_array[irq_level],
+			      0 /* CPL0 routine */);
+      /* A problem occured */
+      if (retval != SOS_OK)
+	sos_irq_handler_array[irq_level] = NULL;
+    }
+  else /* Disable this idt entry */
+    {
+      retval
+	= sos_idt_set_handler(SOS_IRQ_BASE + irq_level,
+			      (sos_vaddr_t)NULL /* Disable IDTE */,
+			      0  /* Don't care */);
+    }
+
+  /* Update the PIC only if an IRQ handler has been set */
+  if (sos_irq_handler_array[irq_level] != NULL)
+    sos_i8259_enable_irq_line(irq_level);
+  else
+    sos_i8259_disable_irq_line(irq_level);
+    
+  sos_restore_IRQs(flags);
+  return retval;
+}
+
+
+sos_irq_handler_t sos_irq_get_routine(int irq_level)
+{
+  if ((irq_level < 0) || (irq_level >= SOS_IRQ_NUM))
+    return NULL;
+  
+  /* Expected to be atomic */
+  return sos_irq_handler_array[irq_level];
+}
+
+
+sos_ui32_t sos_irq_get_nested_level()
+{
+  /* No need to disable interrupts here */
+  return sos_irq_nested_level_counter;
+}