[POWERPC] mpic: Deal with bogus NIRQ in Feature Reporting Register
Kumar Gala [Wed, 21 May 2008 20:59:23 +0000 (06:59 +1000)]
Some chips (like the SoCs from Freescale) report the wrong value in NIRQ
and this causes issues if its doesn't match or exceed the value of
irq_count.

Add a flag that board code can set to just use irq_count instead of
FRR[NIRQ].  Eventually we'll add a device tree property with the number
of sources.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/sysdev/mpic.c
include/asm-powerpc/mpic.h

index 8619f2a..466e218 100644 (file)
@@ -1144,9 +1144,12 @@ struct mpic * __init mpic_alloc(struct device_node *node,
        mpic->num_cpus = ((greg_feature & MPIC_GREG_FEATURE_LAST_CPU_MASK)
                          >> MPIC_GREG_FEATURE_LAST_CPU_SHIFT) + 1;
        if (isu_size == 0)
-               mpic->num_sources =
-                       ((greg_feature & MPIC_GREG_FEATURE_LAST_SRC_MASK)
-                        >> MPIC_GREG_FEATURE_LAST_SRC_SHIFT) + 1;
+               if (flags & MPIC_BROKEN_FRR_NIRQS)
+                       mpic->num_sources = mpic->irq_count;
+               else
+                       mpic->num_sources =
+                               ((greg_feature & MPIC_GREG_FEATURE_LAST_SRC_MASK)
+                                >> MPIC_GREG_FEATURE_LAST_SRC_SHIFT) + 1;
 
        /* Map the per-CPU registers */
        for (i = 0; i < mpic->num_cpus; i++) {
index 943c5a3..6802570 100644 (file)
@@ -353,6 +353,8 @@ struct mpic
 #define MPIC_ENABLE_MCK                        0x00000200
 /* Disable bias among target selection, spread interrupts evenly */
 #define MPIC_NO_BIAS                   0x00000400
+/* Ignore NIRQS as reported by FRR */
+#define MPIC_BROKEN_FRR_NIRQS          0x00000800
 
 /* MPIC HW modification ID */
 #define MPIC_REGSET_MASK               0xf0000000