Interrupts Disabled After First Context Switch

[Kirspel, Kevin {Engineering - Osmetech CCD}]

1) Renesas SH-3 but it's pretty much the same as the SH-4.

2) the rtems_interrupt_disable() routine returns the value in the SR
register of the sh-3/4.  The SR register contains a BL bit that masks
interrupts.  It also contains an interrupt level mask that prevents any
interrupt lower than the level in the SR register from executing.  The
SH4 port sets the interrupt level to 15 to mask all interrupts (
rtems_interrupt_disable ).  Upon the printf statement below, the
interrupt level in the SR register is set to 15 masking all interrupts.

3)Yes.

Case 1: using interrupt mask level 15 to disable interrupts. ( interrupt
masks bits are bits 4-7 which is 0 before and F after).
INT BEFORE: 0x40001000
INT AFTER:  0x400011F1

Case 2: using interrupt BL bit to disable interrupts. ( interrupt BL bit
is bit 28 which is 0 before and 1 after).
INT BEFORE: 0x40001000
INT AFTER:  0x50001101

Kevin Kirspel
Osmetech 
235 Hembree Park Drive
Roswell GA, 30076
770-510-4444 x4568


-----Original Message-----
From: Joel Sherrill <joel at OARcorp.com>
[mailto:joel.sherrill at OARcorp.com] 
Sent: Thursday, January 05, 2006 11:20 AM
To: Kirspel, Kevin {Engineering - Osmetech CCD}
Cc: rtems-users at rtems.com
Subject: Re: Interrupts Disabled After First Context Switch

Kirspel, Kevin {Engineering - Osmetech CCD} wrote:
> Upon entering a task, the interrupts at the hardware level are
enabled.
> After a call to rtems_task_wake_after() the interrupts are disabled
and
> remain disabled while the task is running.  What part of the code
should
> I look at to diagnose this issue? It seems that interrupts get
disabled
> before the task switch is performed.
> 
> The code sample below illustrates what I am doing. At the first
> printf(), the interrupts are enabled.  After the second printf(), the
> interrupts are disabled.
> 
> rtems_task GUITask ( rtems_task_argument ignored )
> {
>   //Local Varaibles
>   rtems_interrupt_level level;
> 
>   /* Wait 100ms til everyone is up and running */
>   rtems_interrupt_disable(level);
>   rtems_interrupt_enable(level);
>   printf( "\r\nINT BEFORE: %08lX", level );
>   rtems_task_wake_after( 10 );
>   rtems_interrupt_disable(level);
>   rtems_interrupt_enable(level);
>   printf ( "\r\nINT AFTER: %08lX", level );
> }

I have more questions than answers.

rtems_interrupt_enable/disable are implemented as inline assembly 
language routines.  They are port specific which leads to

(1) Which CPU are you using?

There is no guarantee on the contents of level after calling enable
so

(2) are you sure they are really off?

(3) can you print out the status register or whatever it is on this CPU 
and we really check?

> Kevin Kirspel
> Osmetech 
> 235 Hembree Park Drive
> Roswell GA, 30076
> 770-510-4444 x4568
> 
> 


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