[v13,8/8] interconnect: Revert to previous config if any request fails

Message ID 20190116161103.6937-9-georgi.djakov@linaro.org
State Accepted
Commit dce6d406669b56506192e726ffbb238e409a7120
Headers show
Series
  • Untitled series #17882
Related show

Commit Message

Georgi Djakov Jan. 16, 2019, 4:11 p.m.
When consumers report their bandwidth needs with icc_set_bw(), it's
possible that the requested amount of bandwidth is not available or just
the new configuration fails to apply on some path. In this case revert to
the previous configuration and propagate the error back to the consumers
to let them know that bandwidth is not available, hardware is busy or
whatever error is returned by the interconnect platform driver.

Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>

---
 drivers/interconnect/core.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

Patch

diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c
index 8091d998549a..6005a1c189f6 100644
--- a/drivers/interconnect/core.c
+++ b/drivers/interconnect/core.c
@@ -414,14 +414,18 @@  EXPORT_SYMBOL_GPL(of_icc_get);
 int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw)
 {
 	struct icc_node *node;
+	u32 old_avg, old_peak;
 	size_t i;
 	int ret;
 
-	if (!path)
+	if (!path || !path->num_nodes)
 		return 0;
 
 	mutex_lock(&icc_lock);
 
+	old_avg = path->reqs[0].avg_bw;
+	old_peak = path->reqs[0].peak_bw;
+
 	for (i = 0; i < path->num_nodes; i++) {
 		node = path->reqs[i].node;
 
@@ -434,10 +438,19 @@  int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw)
 	}
 
 	ret = apply_constraints(path);
-	if (ret)
+	if (ret) {
 		pr_debug("interconnect: error applying constraints (%d)\n",
 			 ret);
 
+		for (i = 0; i < path->num_nodes; i++) {
+			node = path->reqs[i].node;
+			path->reqs[i].avg_bw = old_avg;
+			path->reqs[i].peak_bw = old_peak;
+			aggregate_requests(node);
+		}
+		apply_constraints(path);
+	}
+
 	mutex_unlock(&icc_lock);
 
 	return ret;