Blackfin: enable support for nested interrupts

During cpu init, make sure we initialize the CEC properly so that
interrupts can fire and be handled while U-Boot is running.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

diff --git a/cpu/blackfin/start.S b/cpu/blackfin/start.S
index 8303292..c4d52b4 100644 (file)
--- a/cpu/blackfin/start.S
+++ b/cpu/blackfin/start.S
@@ -75,7 +75,7 @@ ENTRY(_start)
 
        serial_early_puts("Init Registers");
 
 
        serial_early_puts("Init Registers");
 

-       /* Disable nested interrupts and enable CYCLES for udelay() */
+       /* Disable self-nested interrupts and enable CYCLES for udelay() */

        R0 = CCEN | 0x30;
        SYSCFG = R0;
 
        R0 = CCEN | 0x30;
        SYSCFG = R0;
 


@@ -180,7 +180,7 @@ ENTRY(_start)
 
        /* Now lower ourselves from the highest interrupt level to
         * the lowest.  We do this by masking all interrupts but 15,
 
        /* Now lower ourselves from the highest interrupt level to
         * the lowest.  We do this by masking all interrupts but 15,

-        * setting the 15 handler to "board_init_f", raising the 15
+        * setting the 15 handler to ".Lenable_nested", raising the 15

         * interrupt, and then returning from the highest interrupt
         * level to the dummy "jump" until the interrupt controller
         * services the pending 15 interrupt.
         * interrupt, and then returning from the highest interrupt
         * level to the dummy "jump" until the interrupt controller
         * services the pending 15 interrupt.


@@ -190,8 +190,8 @@ ENTRY(_start)
        r1 = r6;
        p0.l = LO(EVT15);
        p0.h = HI(EVT15);
        r1 = r6;
        p0.l = LO(EVT15);
        p0.h = HI(EVT15);

-       p1.l = _cpu_init_f;
-       p1.h = _cpu_init_f;
+       p1.l = .Lenable_nested;
+       p1.h = .Lenable_nested;

        [p0] = p1;
        p2.l = LO(IMASK);
        p2.h = HI(IMASK);
        [p0] = p1;
        p2.l = LO(IMASK);
        p2.h = HI(IMASK);


@@ -204,6 +204,12 @@ ENTRY(_start)
        reti = p4;
        rti;
 
        reti = p4;
        rti;
 

+       /* Enable nested interrupts before continuing with cpu init */
+.Lenable_nested:
+       cli r7;
+       [--sp] = reti;
+       jump.l _cpu_init_f;
+

 .LWAIT_HERE:
        jump .LWAIT_HERE;
 ENDPROC(_start)
 .LWAIT_HERE:
        jump .LWAIT_HERE;
 ENDPROC(_start)