[PATCH v3 1/3] pmdomain: rockchip: remove subdomain links before the domains on error

[Arun Iyengar via B4 Relay <devnull+aiyengar1990.gmail.com@kernel.org>]

From: Arun Iyengar <aiyengar1990@gmail.com>

When probe fails after some domains were registered, the cleanup calls
pm_genpd_remove() in domain id order. That fails with -EBUSY for every
domain that is still a parent. Reversing the order does not help: on
RK3588 RKVDEC0/1 have a parent with a lower and one with a higher id.
devm then frees those domains while they are still on gpd_list.

Remove the parent/child links first, depth first over the DT nodes.

Fixes: 79d12b7a7f22 ("soc: rockchip: power-domain: use pm_genpd_remove in error cleanup")
Cc: stable@vger.kernel.org
Signed-off-by: Arun Iyengar <aiyengar1990@gmail.com>
---
 drivers/pmdomain/rockchip/pm-domains.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/drivers/pmdomain/rockchip/pm-domains.c b/drivers/pmdomain/rockchip/pm-domains.c
index 86b5074b0469..df3f43d0c01b 100644
--- a/drivers/pmdomain/rockchip/pm-domains.c
+++ b/drivers/pmdomain/rockchip/pm-domains.c
@@ -955,12 +955,45 @@ static void rockchip_pm_remove_one_domain(struct rockchip_pm_domain *pd)
 	/* devm will free our memory */
 }
 
+static struct generic_pm_domain *
+rockchip_pm_node_to_genpd(struct rockchip_pmu *pmu, struct device_node *node)
+{
+	u32 id;
+
+	if (of_property_read_u32(node, "reg", &id) ||
+	    id >= pmu->genpd_data.num_domains)
+		return NULL;
+
+	return pmu->genpd_data.domains[id];
+}
+
+/* Remove the links depth first, so each child has no subdomains left. */
+static void rockchip_pm_remove_subdomains(struct rockchip_pmu *pmu,
+					  struct device_node *parent)
+{
+	struct generic_pm_domain *parent_domain, *child_domain;
+
+	parent_domain = rockchip_pm_node_to_genpd(pmu, parent);
+
+	for_each_child_of_node_scoped(parent, np) {
+		rockchip_pm_remove_subdomains(pmu, np);
+
+		child_domain = rockchip_pm_node_to_genpd(pmu, np);
+		if (parent_domain && child_domain)
+			pm_genpd_remove_subdomain(parent_domain, child_domain);
+	}
+}
+
 static void rockchip_pm_domain_cleanup(struct rockchip_pmu *pmu)
 {
 	struct generic_pm_domain *genpd;
 	struct rockchip_pm_domain *pd;
 	int i;
 
+	/* pm_genpd_remove() refuses a domain that still has subdomains */
+	for_each_available_child_of_node_scoped(pmu->dev->of_node, np)
+		rockchip_pm_remove_subdomains(pmu, np);
+
 	for (i = 0; i < pmu->genpd_data.num_domains; i++) {
 		genpd = pmu->genpd_data.domains[i];
 		if (genpd) {

-- 
2.55.0