soc: qcom: subsystem_notif_virt: Add waitqueue support for SSR

Add blocking support for SSR on the GHS platform. SSR will
block until receiving acknowledgment.

Change-Id: I549908f702318fc9e9dca5cdb12ad353881b6991
Signed-off-by: Anant Goel <anantg@codeaurora.org>

diff --git a/drivers/soc/qcom/subsystem_notif_virt.c b/drivers/soc/qcom/subsystem_notif_virt.c
index cfeebed..2adbf1d 100644 (file)
--- a/drivers/soc/qcom/subsystem_notif_virt.c
+++ b/drivers/soc/qcom/subsystem_notif_virt.c
@@ -77,17 +77,36 @@ static struct workqueue_struct *ssr_wq;
 
 
 #ifdef CONFIG_GHS_VMM
+enum subsys_payload_type {
+       SUBSYS_CHANNEL_SEND = 100,
+       SUBSYS_CHANNEL_RECV,
+       SUBSYS_CHANNEL_SEND_ACK,
+       SUBSYS_CHANNEL_RECV_ACK
+};
+
 struct ghs_vdev {
        void *read_data; /* buffer to receive from gipc */
        size_t read_size;
        int read_offset;
        GIPC_Endpoint endpoint;
        spinlock_t io_lock;
+       wait_queue_head_t rx_queue;
+       int xfer_state;
        char name[32];
 };
 
 static char dt_gipc_path_name[SSR_VIRT_DT_PATHLEN];
 
+static int ssrvirt_channel_ack(struct ghs_vdev *dev)
+{
+       int ret = 0;
+
+       ret = wait_event_interruptible(dev->rx_queue, ((dev->read_size != 0) ||
+                               (dev->xfer_state == SUBSYS_CHANNEL_SEND_ACK)));
+
+       return ret;
+}
+
 static int ssrvirt_channel_send(struct ghs_vdev *dev, void *payload,
                size_t size)
 {
@@ -109,6 +128,8 @@ static int ssrvirt_channel_send(struct ghs_vdev *dev, void *payload,
                return -ENOMEM;
        }
 
+       dev->xfer_state = SUBSYS_CHANNEL_SEND;
+
        if (size)
                memcpy(msg, payload, size);
 
@@ -122,6 +143,8 @@ static int ssrvirt_channel_send(struct ghs_vdev *dev, void *payload,
                return -EAGAIN;
        }
 
+       ssrvirt_channel_ack(dev);
+
        return 0;
 }
 
@@ -171,6 +194,14 @@ static void ssrvirt_channel_rx_dispatch(struct subsystem_descriptor *subsystem,
                                subsystem_handle =
                                        subsys_notif_add_subsys(
                                                        subsystem->name);
+
+                               if (state == SUBSYS_CHANNEL_SEND_ACK) {
+                                       dev->xfer_state =
+                                               SUBSYS_CHANNEL_SEND_ACK;
+                                       wake_up_interruptible(&dev->rx_queue);
+                                       continue;
+                               }
+
                                subsys_notif_queue_notification(
                                                subsystem_handle, state, NULL);
                        }
@@ -209,6 +240,7 @@ static int ssrvirt_commdev_alloc(void *dev_id, const char *name)
 
        memset(dev, 0, sizeof(*dev));
        spin_lock_init(&dev->io_lock);
+       init_waitqueue_head(&dev->rx_queue);
 
        gvh_dn = of_find_node_by_path("/aliases");
        if (gvh_dn) {