greybus: svc: add interface resume operation

Add the AP implementation for the Greybus SVC Interface Resume
Operation. This operation allows the AP to request the SVC to resume an
Interface which was previously SUSPENDED, allowing it to later be
ENUMERATED.
Signed-off-by: David Lin <dtwlin@google.com>
Reviewed-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Alex Elder <elder@linaro.org>

drivers/staging/greybus/greybus_protocols.h

@@ -1001,6 +1001,7 @@ struct gb_spi_transfer_response {
 #define GB_SVC_TYPE_INTF_UNIPRO_ENABLE		0x25
 #define GB_SVC_TYPE_INTF_UNIPRO_DISABLE		0x26
 #define GB_SVC_TYPE_INTF_ACTIVATE		0x27
+#define GB_SVC_TYPE_INTF_RESUME			0x28
 #define GB_SVC_TYPE_INTF_MAILBOX_EVENT		0x29
 
 /* Greybus SVC protocol status values */
@@ -1321,6 +1322,14 @@ struct gb_svc_intf_activate_response {
 	__u8	intf_type;
 } __packed;
 
+struct gb_svc_intf_resume_request {
+	__u8	intf_id;
+} __packed;
+
+struct gb_svc_intf_resume_response {
+	__u8	status;
+} __packed;
+
 #define GB_SVC_INTF_MAILBOX_NONE		0x00
 #define GB_SVC_INTF_MAILBOX_AP			0x01
 #define GB_SVC_INTF_MAILBOX_GREYBUS		0x02

drivers/staging/greybus/svc.c

@@ -14,6 +14,7 @@
 
 #define SVC_INTF_EJECT_TIMEOUT		9000
 #define SVC_INTF_ACTIVATE_TIMEOUT	6000
+#define SVC_INTF_RESUME_TIMEOUT	3000
 
 struct gb_svc_deferred_request {
 	struct work_struct work;
@@ -354,6 +355,34 @@ int gb_svc_intf_activate(struct gb_svc *svc, u8 intf_id, u8 *intf_type)
 	return 0;
 }
 
+int gb_svc_intf_resume(struct gb_svc *svc, u8 intf_id)
+{
+	struct gb_svc_intf_resume_request request;
+	struct gb_svc_intf_resume_response response;
+	int ret;
+
+	request.intf_id = intf_id;
+
+	ret = gb_operation_sync_timeout(svc->connection,
+					GB_SVC_TYPE_INTF_RESUME,
+					&request, sizeof(request),
+					&response, sizeof(response),
+					SVC_INTF_RESUME_TIMEOUT);
+	if (ret < 0) {
+		dev_err(&svc->dev, "failed to send interface resume %u: %d\n",
+			intf_id, ret);
+		return ret;
+	}
+
+	if (response.status != GB_SVC_OP_SUCCESS) {
+		dev_err(&svc->dev, "failed to resume interface %u: %u\n",
+			intf_id, response.status);
+		return -EREMOTEIO;
+	}
+
+	return 0;
+}
+
 int gb_svc_dme_peer_get(struct gb_svc *svc, u8 intf_id, u16 attr, u16 selector,
 			u32 *value)
 {

drivers/staging/greybus/svc.h

@@ -71,6 +71,8 @@ int gb_svc_intf_vsys_set(struct gb_svc *svc, u8 intf_id, bool enable);
 int gb_svc_intf_refclk_set(struct gb_svc *svc, u8 intf_id, bool enable);
 int gb_svc_intf_unipro_set(struct gb_svc *svc, u8 intf_id, bool enable);
 int gb_svc_intf_activate(struct gb_svc *svc, u8 intf_id, u8 *intf_type);
+int gb_svc_intf_resume(struct gb_svc *svc, u8 intf_id);
+
 int gb_svc_dme_peer_get(struct gb_svc *svc, u8 intf_id, u16 attr, u16 selector,
 			u32 *value);
 int gb_svc_dme_peer_set(struct gb_svc *svc, u8 intf_id, u16 attr, u16 selector,