firmware: psci: register PSCI power domains to stub driver

On some SoCs, like Qualcomm SoCs, the PSCI cluster power domain
is used by system-wide firmware interfaces to make sure none
of the CPUs are suspended before submitting requests.

While on U-boot we only use the first core and we never
suspend it, the Device Tree still references it and blocks
those nodes to be probed.

Simply bind the PSCI power-domain subnoded to a stub power
domain driver in order to solve the runtime dependencies.

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>

diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
index c32c3f5c6a54fc8cea0a55ba5bc08675d4347ce4..2e3223e1c32a0f7cbdd13debea4cb1a090e0b3eb 100644 (file)
--- a/drivers/firmware/psci.c
+++ b/drivers/firmware/psci.c
@@ -22,6 +22,7 @@
 #include <linux/libfdt.h>
 #include <linux/printk.h>
 #include <linux/psci.h>
+#include <power-domain-uclass.h>
 
 #define DRIVER_NAME "psci"
 
@@ -171,6 +172,10 @@ static int bind_smccc_features(struct udevice *dev, int psci_method)
 
 static int psci_bind(struct udevice *dev)
 {
+#if IS_ENABLED(CONFIG_POWER_DOMAIN)
+       ofnode node;
+#endif
+
        /* No SYSTEM_RESET support for PSCI 0.1 */
        if (device_is_compatible(dev, "arm,psci-0.2") ||
            device_is_compatible(dev, "arm,psci-1.0")) {
@@ -187,6 +192,16 @@ static int psci_bind(struct udevice *dev)
        if (IS_ENABLED(CONFIG_ARM_SMCCC_FEATURES) && device_is_compatible(dev, "arm,psci-1.0"))
                dev_or_flags(dev, DM_FLAG_PROBE_AFTER_BIND);
 
+       /* Bind power-domain subnodes */
+#if IS_ENABLED(CONFIG_POWER_DOMAIN)
+       dev_for_each_subnode(node, dev) {
+               if (device_bind_driver_to_node(dev, "psci_power_domain",
+                                              ofnode_get_name(node),
+                                              node, NULL))
+                       pr_warn("failed to bind %s\n", ofnode_get_name(node));
+       }
+#endif
+
        return 0;
 }
 
@@ -323,3 +338,29 @@ U_BOOT_DRIVER(psci) = {
 #endif
        .flags = DM_FLAG_PRE_RELOC,
 };
+
+#if IS_ENABLED(CONFIG_POWER_DOMAIN)
+/* Accept #power-domain-cells == 0 */
+static int psci_power_domain_xlate(struct power_domain *power_domain,
+                                  struct ofnode_phandle_args *args)
+{
+       return args->args_count == 0 ? 0 : -EINVAL;
+}
+
+static const struct power_domain_ops psci_power_ops = {
+       .of_xlate = psci_power_domain_xlate,
+};
+
+static int psci_power_domain_probe(struct udevice *dev)
+{
+       return 0;
+}
+
+U_BOOT_DRIVER(psci_power_domain) = {
+       .name = "psci_power_domain",
+       .id = UCLASS_POWER_DOMAIN,
+       .ops = &psci_power_ops,
+       .probe = psci_power_domain_probe,
+       .flags = DM_FLAG_PRE_RELOC,
+};
+#endif