greybus: interface: Add quirk for no PM for S2 Loader

S2 Loader doesn't support runtime PM operations currently and we will
fail to suspend/resume the bundle for firmware management protocols.

Once that happens, the bundle and its connections will be pretty much
useless as we would have tried to disable/enable all connections during
such an operation and the S2 loader doesn't expect the connections to go
away during normal operation (except in the case of mode-switch).

This patch defines a new quirk GB_INTERFACE_QUIRK_NO_PM and uses a new
interface init status value (GB_INIT_S2_LOADER_INITIALIZED) which will
be advertised by S2 Loader now in the init status.

After detecting the currently running stage as S2 Loader, the kernel
wouldn't attempt suspending or resuming the bundle.

Reviewed-by: David Lin <dtwlin@google.com>
Reviewed-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/fw-core.c

@@ -228,7 +228,9 @@ static int gb_fw_core_probe(struct gb_bundle *bundle,
 
 	greybus_set_drvdata(bundle, fw_core);
 
-	gb_pm_runtime_put_autosuspend(bundle);
+	/* FIXME: Remove this after S2 Loader gets runtime PM support */
+	if (!(bundle->intf->quirks & GB_INTERFACE_QUIRK_NO_PM))
+		gb_pm_runtime_put_autosuspend(bundle);
 
 	return 0;
 
@@ -251,9 +253,12 @@ static void gb_fw_core_disconnect(struct gb_bundle *bundle)
 	struct gb_fw_core *fw_core = greybus_get_drvdata(bundle);
 	int ret;
 
-	ret = gb_pm_runtime_get_sync(bundle);
-	if (ret)
-		gb_pm_runtime_get_noresume(bundle);
+	/* FIXME: Remove this after S2 Loader gets runtime PM support */
+	if (!(bundle->intf->quirks & GB_INTERFACE_QUIRK_NO_PM)) {
+		ret = gb_pm_runtime_get_sync(bundle);
+		if (ret)
+			gb_pm_runtime_get_noresume(bundle);
+	}
 
 	gb_fw_mgmt_connection_exit(fw_core->mgmt_connection);
 	gb_cap_connection_exit(fw_core->cap_connection);

drivers/staging/greybus/greybus_protocols.h

@@ -1145,6 +1145,7 @@ struct gb_svc_dme_peer_set_response {
 #define GB_INIT_UNTRUSTED_SPI_BOOT_FINISHED		0x04
 #define GB_INIT_BOOTROM_UNIPRO_BOOT_STARTED		0x06
 #define GB_INIT_BOOTROM_FALLBACK_UNIPRO_BOOT_STARTED	0x09
+#define GB_INIT_S2_LOADER_BOOT_STARTED			0x0D
 
 struct gb_svc_route_create_request {
 	__u8	intf1_id;

drivers/staging/greybus/interface.c

@@ -363,6 +363,7 @@ static int gb_interface_read_and_clear_init_status(struct gb_interface *intf)
 {
 	struct gb_host_device *hd = intf->hd;
 	unsigned long bootrom_quirks;
+	unsigned long s2l_quirks;
 	int ret;
 	u32 value;
 	u16 attr;
@@ -413,13 +414,22 @@ static int gb_interface_read_and_clear_init_status(struct gb_interface *intf)
 				GB_INTERFACE_QUIRK_FORCED_DISABLE |
 				GB_INTERFACE_QUIRK_LEGACY_MODE_SWITCH |
 				GB_INTERFACE_QUIRK_NO_BUNDLE_ACTIVATE;
+
+	s2l_quirks = GB_INTERFACE_QUIRK_NO_PM;
+
 	switch (init_status) {
 	case GB_INIT_BOOTROM_UNIPRO_BOOT_STARTED:
 	case GB_INIT_BOOTROM_FALLBACK_UNIPRO_BOOT_STARTED:
 		intf->quirks |= bootrom_quirks;
 		break;
+	case GB_INIT_S2_LOADER_BOOT_STARTED:
+		/* S2 Loader doesn't support runtime PM */
+		intf->quirks &= ~bootrom_quirks;
+		intf->quirks |= s2l_quirks;
+		break;
 	default:
 		intf->quirks &= ~bootrom_quirks;
+		intf->quirks &= ~s2l_quirks;
 	}
 
 	/* Clear the init status. */

drivers/staging/greybus/interface.h

@@ -24,6 +24,7 @@ enum gb_interface_type {
 #define GB_INTERFACE_QUIRK_FORCED_DISABLE		BIT(3)
 #define GB_INTERFACE_QUIRK_LEGACY_MODE_SWITCH		BIT(4)
 #define GB_INTERFACE_QUIRK_NO_BUNDLE_ACTIVATE		BIT(5)
+#define GB_INTERFACE_QUIRK_NO_PM			BIT(6)
 
 struct gb_interface {
 	struct device dev;