powerpc/pseries: Check for GIQ indicator before calling set-indicator

Since "Factor out cpu joining/unjoining the GIQ"
(b4963255ad5a426f04a0bb15c4315fa4bb40cde9) the WARN_ON in
xics_set_cpu_giq() is being triggered during boot on JS20 because the
GIQ indicator is not available on that platform.  While the warning is
harmless and the system runs normally, it's nicer to check for the
existence of the indicator before trying to manipulate it.

Implement rtas_indicator_present(), which searches the
/rtas/rtas-indicators property for the given indicator token, and use
this function in xics_set_cpu_giq().

Also use a WARN statement in xics_set_cpu_giq to get better
information on failure.

Signed-off-by: Nathan Lynch <ntl@pobox.com>
Acked-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 26 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 1f8505c..fdfe14c 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -566,6 +566,32 @@ int rtas_get_sensor(int sensor, int index, int *state)
 }
 EXPORT_SYMBOL(rtas_get_sensor);
 
+bool rtas_indicator_present(int token, int *maxindex)
+{
+	int proplen, count, i;
+	const struct indicator_elem {
+		u32 token;
+		u32 maxindex;
+	} *indicators;
+
+	indicators = of_get_property(rtas.dev, "rtas-indicators", &proplen);
+	if (!indicators)
+		return false;
+
+	count = proplen / sizeof(struct indicator_elem);
+
+	for (i = 0; i < count; i++) {
+		if (indicators[i].token != token)
+			continue;
+		if (maxindex)
+			*maxindex = indicators[i].maxindex;
+		return true;
+	}
+
+	return false;
+}
+EXPORT_SYMBOL(rtas_indicator_present);
+
 int rtas_set_indicator(int indicator, int index, int new_value)
 {
 	int token = rtas_token("set-indicator");