[PATCH RFC 21/27] drivers: cpu-pd: Parse topology to setup CPU PM domains

[Lina Iyer <lina.iyer@linaro.org>]

Architectures that support CPU domain control in the firmware specify
the domain heirarchy as part of the topology nodes. Parse and initialize
domains from the topology node for such architectures.

Cc: Rob Herring <robherring2@gmail.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 drivers/base/power/cpu-pd.c | 76 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/cpu-pd.h      |  1 +
 2 files changed, 77 insertions(+)

diff --git a/drivers/base/power/cpu-pd.c b/drivers/base/power/cpu-pd.c
index e331ae6..2872c18 100644
--- a/drivers/base/power/cpu-pd.c
+++ b/drivers/base/power/cpu-pd.c
@@ -429,3 +429,79 @@ int of_attach_cpu_pm_domain(struct device_node *dn)
 	return 0;
 }
 EXPORT_SYMBOL(of_attach_cpu_pm_domain);
+
+static int of_parse_cpu_pd(struct device_node *cluster,
+		const struct cpu_pd_ops *ops)
+{
+	struct device_node *domain_node;
+	struct generic_pm_domain *genpd;
+	char name[10];
+	struct device_node *c;
+	int i, ret;
+
+	for (i = 0; ; i++) {
+		snprintf(name, sizeof(name), "cluster%d", i);
+		c = of_get_child_by_name(cluster, name);
+		if (!c)
+			break;
+
+		domain_node = of_parse_phandle(c, "cluster", 0);
+		if (!domain_node)
+			return -1;
+
+		/* Initialize CPU PM domain domain at this level */
+		genpd = of_init_cpu_pm_domain(domain_node, ops);
+		if (IS_ERR(genpd))
+			return -1;
+
+		/* Initialize and attach child domains */
+		ret = of_parse_cpu_pd(c, ops);
+
+		/*
+		 * Attach the domain to its parent after reading
+		 * the children, so the mask of CPUs in this domain
+		 * are setup correctly.
+		 */
+		if (!ret)
+			of_attach_cpu_pm_domain(domain_node);
+
+		of_node_put(c);
+		if (ret != 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * of_setup_cpu_domain_topology() - Setup the CPU domains from the CPU
+ * topology node in DT.
+ *
+ * @ops: The PM domain suspend/resume ops for all the domains in the topology
+ */
+int of_setup_cpu_domain_topology(const struct cpu_pd_ops *ops)
+{
+	struct device_node *cn, *map;
+	int ret = 0;
+
+	cn = of_find_node_by_path("/cpus");
+	if (!cn) {
+		pr_err("No CPU information found in DT\n");
+		return 0;
+	}
+
+	map = of_get_child_by_name(cn, "cpu-map");
+	if (!map)
+		goto out;
+
+	ret = of_parse_cpu_pd(map, ops);
+	if (ret != 0)
+		goto out_map;
+
+out_map:
+	of_node_put(map);
+out:
+	of_node_put(cn);
+	return ret;
+}
+EXPORT_SYMBOL(of_setup_cpu_domain_topology);
diff --git a/include/linux/cpu-pd.h b/include/linux/cpu-pd.h
index 489ee2f..e8290db 100644
--- a/include/linux/cpu-pd.h
+++ b/include/linux/cpu-pd.h
@@ -32,4 +32,5 @@ struct cpu_pm_domain {
 struct generic_pm_domain *of_init_cpu_pm_domain(struct device_node *dn,
 		const struct cpu_pd_ops *ops);
 int of_attach_cpu_pm_domain(struct device_node *dn);
+int of_setup_cpu_domain_topology(const struct cpu_pd_ops *ops);
 #endif /* __CPU_PD_H__ */
-- 
2.1.4