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path: root/drivers/dma/amba-pl08x.c
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Diffstat (limited to 'drivers/dma/amba-pl08x.c')
-rw-r--r--drivers/dma/amba-pl08x.c22
1 files changed, 16 insertions, 6 deletions
diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index fc8c2bab563c..8cfc753ad4b0 100644
--- 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;
}
}