Merge tag 'gcc-plugins-v5.2-rc1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel...

[linux-2.6-microblaze.git] / drivers / dma / amba-pl08x.c

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index fc8c2ba..8cfc753 100644 (file)
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -254,6 +254,7 @@ enum pl08x_dma_chan_state {
  * @slave: whether this channel is a device (slave) or for memcpy
  * @signal: the physical DMA request signal which this channel is using
  * @mux_use: count of descriptors using this DMA request signal setting
+ * @waiting_at: time in jiffies when this channel moved to waiting state
  */
 struct pl08x_dma_chan {
        struct virt_dma_chan vc;
@@ -267,6 +268,7 @@ struct pl08x_dma_chan {
        bool slave;
        int signal;
        unsigned mux_use;
+       unsigned long waiting_at;
 };
 
 /**
@@ -875,6 +877,7 @@ static void pl08x_phy_alloc_and_start(struct pl08x_dma_chan *plchan)
        if (!ch) {
                dev_dbg(&pl08x->adev->dev, "no physical channel available for xfer on %s\n", plchan->name);
                plchan->state = PL08X_CHAN_WAITING;
+               plchan->waiting_at = jiffies;
                return;
        }
 
@@ -913,22 +916,29 @@ static void pl08x_phy_free(struct pl08x_dma_chan *plchan)
 {
        struct pl08x_driver_data *pl08x = plchan->host;
        struct pl08x_dma_chan *p, *next;
-
+       unsigned long waiting_at;
  retry:
        next = NULL;
+       waiting_at = jiffies;
 
-       /* Find a waiting virtual channel for the next transfer. */
+       /*
+        * Find a waiting virtual channel for the next transfer.
+        * To be fair, time when each channel reached waiting state is compared
+        * to select channel that is waiting for the longest time.
+        */
        list_for_each_entry(p, &pl08x->memcpy.channels, vc.chan.device_node)
-               if (p->state == PL08X_CHAN_WAITING) {
+               if (p->state == PL08X_CHAN_WAITING &&
+                   p->waiting_at <= waiting_at) {
                        next = p;
-                       break;
+                       waiting_at = p->waiting_at;
                }
 
        if (!next && pl08x->has_slave) {
                list_for_each_entry(p, &pl08x->slave.channels, vc.chan.device_node)
-                       if (p->state == PL08X_CHAN_WAITING) {
+                       if (p->state == PL08X_CHAN_WAITING &&
+                           p->waiting_at <= waiting_at) {
                                next = p;
-                               break;
+                               waiting_at = p->waiting_at;
                        }
        }