/* 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;
 }