mei: rx flow control counter

Use RX flow control counter in the host client structure to
track the number of simultaneous outstanding reads.
This eliminates search in queues and makes ground for
enabling for parallel read.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/mei/amthif.c b/drivers/misc/mei/amthif.c
index 26568c5beb25e75f9ef7ea268dacb2ee8b1652cb..227fd5a816a6f70d5bcaebea5cfb9d5517dce409 100644 (file)
--- a/drivers/misc/mei/amthif.c
+++ b/drivers/misc/mei/amthif.c
@@ -202,6 +202,7 @@ static int mei_amthif_read_start(struct mei_cl *cl, const struct file *file)
                return -ENOMEM;
 
        list_add_tail(&cb->list, &dev->ctrl_wr_list.list);
+       cl->rx_flow_ctrl_creds++;
 
        dev->iamthif_state = MEI_IAMTHIF_READING;
        cl->fp = cb->fp;

diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index 05cacc3e718f888395054b686875cf40e7c93a61..ded11de90a2671dec238397217269c2d9e6602e9 100644 (file)
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -735,6 +735,7 @@ void mei_cl_set_disconnected(struct mei_cl *cl)
        mei_io_list_flush(&dev->ctrl_wr_list, cl);
        mei_cl_wake_all(cl);
        cl->mei_flow_ctrl_creds = 0;
+       cl->rx_flow_ctrl_creds = 0;
        cl->timer_count = 0;
 
        if (!cl->me_cl)
@@ -1408,25 +1409,6 @@ out:
        return 0;
 }
 
-/**
- * mei_cl_is_read_fc_cb - check if read cb is waiting for flow control
- *                        for given host client
- *
- * @cl: host client
- *
- * Return: true, if found at least one cb.
- */
-static bool mei_cl_is_read_fc_cb(struct mei_cl *cl)
-{
-       struct mei_device *dev = cl->dev;
-       struct mei_cl_cb *cb;
-
-       list_for_each_entry(cb, &dev->ctrl_wr_list.list, list)
-               if (cb->fop_type == MEI_FOP_READ && cb->cl == cl)
-                       return true;
-       return false;
-}
-
 /**
  * mei_cl_read_start - the start read client message function.
  *
@@ -1450,10 +1432,6 @@ int mei_cl_read_start(struct mei_cl *cl, size_t length, const struct file *fp)
        if (!mei_cl_is_connected(cl))
                return -ENODEV;
 
-       /* HW currently supports only one pending read */
-       if (!list_empty(&cl->rd_pending) || mei_cl_is_read_fc_cb(cl))
-               return -EBUSY;
-
        if (!mei_me_cl_is_active(cl->me_cl)) {
                cl_err(dev, cl, "no such me client\n");
                return  -ENOTTY;
@@ -1462,12 +1440,18 @@ int mei_cl_read_start(struct mei_cl *cl, size_t length, const struct file *fp)
        if (mei_cl_is_fixed_address(cl))
                return 0;
 
+       /* HW currently supports only one pending read */
+       if (cl->rx_flow_ctrl_creds)
+               return -EBUSY;
+
        /* always allocate at least client max message */
        length = max_t(size_t, length, mei_cl_mtu(cl));
        cb = mei_cl_alloc_cb(cl, length, MEI_FOP_READ, fp);
        if (!cb)
                return -ENOMEM;
 
+       list_add_tail(&cb->list, &dev->ctrl_wr_list.list);
+
        rets = pm_runtime_get(dev->dev);
        if (rets < 0 && rets != -EINPROGRESS) {
                pm_runtime_put_noidle(dev->dev);
@@ -1475,16 +1459,15 @@ int mei_cl_read_start(struct mei_cl *cl, size_t length, const struct file *fp)
                goto nortpm;
        }
 
+       rets = 0;
        if (mei_hbuf_acquire(dev)) {
                rets = mei_hbm_cl_flow_control_req(dev, cl);
                if (rets < 0)
                        goto out;
 
-               list_add_tail(&cb->list, &cl->rd_pending);
-       } else {
-               rets = 0;
-               list_add_tail(&cb->list, &dev->ctrl_wr_list.list);
+               list_move_tail(&cb->list, &cl->rd_pending);
        }
+       cl->rx_flow_ctrl_creds++;
 
 out:
        cl_dbg(dev, cl, "rpm: autosuspend\n");
@@ -1732,6 +1715,9 @@ void mei_cl_complete(struct mei_cl *cl, struct mei_cl_cb *cb)
 
        case MEI_FOP_READ:
                list_add_tail(&cb->list, &cl->rd_completed);
+               if (!mei_cl_is_fixed_address(cl) &&
+                   !WARN_ON(!cl->rx_flow_ctrl_creds))
+                       cl->rx_flow_ctrl_creds--;
                if (!mei_cl_bus_rx_event(cl))
                        wake_up_interruptible(&cl->rx_wait);
                break;

diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index aaefbc87c2fc66c8ac60cf0f8d83cb7a9333d250..8bdb280544237bcef9dd5011e36a762a17b1c684 100644 (file)
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -203,8 +203,8 @@ struct mei_cl_cb {
  * @fp: file associated with client
  * @host_client_id: host id
  * @mei_flow_ctrl_creds: transmit flow credentials
+ * @rx_flow_ctrl_creds: receive flow credentials
  * @timer_count:  watchdog timer for operation completion
- * @reserved: reserved for alignment
  * @notify_en: notification - enabled/disabled
  * @notify_ev: pending notification event
  * @writing_state: state of the tx
@@ -227,8 +227,8 @@ struct mei_cl {
        const struct file *fp;
        u8 host_client_id;
        u8 mei_flow_ctrl_creds;
+       u8 rx_flow_ctrl_creds;
        u8 timer_count;
-       u8 reserved;
        u8 notify_en;
        u8 notify_ev;
        enum mei_file_transaction_states writing_state;