Coldfire: Fix the modification of IMR. Interrupts must be masked at the core level at at least the level of the interrupt being masked. Not following the datasheet and relying strictly on and/or_l causes unhandled 'Levelx' exceptions (showing itself quite often in PCM mixer work which more greatly stresses PCM lockout).

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30009 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 11 insertions, 1 deletions

diff --git a/firmware/target/coldfire/system-coldfire.c b/firmware/target/coldfire/system-coldfire.c
index 61a5da98cd..1fbd00825a 100644
--- a/firmware/target/coldfire/system-coldfire.c
+++ b/firmware/target/coldfire/system-coldfire.c
@@ -268,7 +268,7 @@ void system_init(void)
        will do. */
     coldfire_set_macsr(EMAC_FRACTIONAL | EMAC_SATURATE);
     
-    IMR = 0x3ffff;
+    coldfire_imr_mod(0x3ffff, 0x3ffff);
     INTPRI1 = 0;
     INTPRI2 = 0;
     INTPRI3 = 0;
@@ -365,6 +365,16 @@ void coldfire_set_pllcr_audio_bits(long bits)
     PLLCR = (PLLCR & ~0x70400000) | (bits & 0x70400000);
 }
 
+/* Safely modify the interrupt mask register as the core interrupt level is
+   required to be at least as high as the level interrupt being
+   masked/unmasked */
+void coldfire_imr_mod(unsigned long bits, unsigned long mask)
+{
+    unsigned long oldlevel = set_irq_level(DISABLE_INTERRUPTS);
+    IMR = (IMR & ~mask) | (bits & mask);
+    restore_irq(oldlevel);
+}
+
 /* Set DATAINCONTROL without disturbing FIFO reset state */
 void coldfire_set_dataincontrol(unsigned long value)
 {