irqchip/gic-v3: Dynamically allocate PPI partition descriptors

Again, PPIs are becoming a variable set. Let's hack the PPI partition
code to make the top-level array dynamically allocated.
Signed-off-by: Marc Zyngier <maz@kernel.org>

drivers/irqchip/irq-gic-v3.c

@@ -52,7 +52,7 @@ struct gic_chip_data {
 	u64			flags;
 	bool			has_rss;
 	unsigned int		ppi_nr;
-	struct partition_desc	*ppi_descs[16];
+	struct partition_desc	**ppi_descs;
 };
 
 static struct gic_chip_data gic_data __read_mostly;
@@ -1354,7 +1354,8 @@ static int gic_irq_domain_select(struct irq_domain *d,
 	 * then we need to match the partition domain.
 	 */
 	if (fwspec->param_count >= 4 &&
-	    fwspec->param[0] == 1 && fwspec->param[3] != 0)
+	    fwspec->param[0] == 1 && fwspec->param[3] != 0 &&
+	    gic_data.ppi_descs)
 		return d == partition_get_domain(gic_data.ppi_descs[fwspec->param[1]]);
 
 	return d == gic_data.domain;
@@ -1375,6 +1376,9 @@ static int partition_domain_translate(struct irq_domain *d,
 	struct device_node *np;
 	int ret;
 
+	if (!gic_data.ppi_descs)
+		return -ENOMEM;
+
 	np = of_find_node_by_phandle(fwspec->param[3]);
 	if (WARN_ON(!np))
 		return -EINVAL;
@@ -1531,6 +1535,10 @@ static void __init gic_populate_ppi_partitions(struct device_node *gic_node)
 	if (!parts_node)
 		return;
 
+	gic_data.ppi_descs = kcalloc(gic_data.ppi_nr, sizeof(*gic_data.ppi_descs), GFP_KERNEL);
+	if (!gic_data.ppi_descs)
+		return;
+
 	nr_parts = of_get_child_count(parts_node);
 
 	if (!nr_parts)
@@ -1582,7 +1590,7 @@ static void __init gic_populate_ppi_partitions(struct device_node *gic_node)
 		part_idx++;
 	}
 
-	for (i = 0; i < 16; i++) {
+	for (i = 0; i < gic_data.ppi_nr; i++) {
 		unsigned int irq;
 		struct partition_desc *desc;
 		struct irq_fwspec ppi_fwspec = {